The predictive value of the ratio of neck circumference to thyromental distance in comparison with four predictive tests for difficult laryngoscopy in obstetric patients scheduled for caesarean delivery
Identifieur interne : 002807 ( Pmc/Corpus ); précédent : 002806; suivant : 002808The predictive value of the ratio of neck circumference to thyromental distance in comparison with four predictive tests for difficult laryngoscopy in obstetric patients scheduled for caesarean delivery
Auteurs : Anahita Hirmanpour ; Mohammadreza Safavi ; Azim Honarmand ; Mitra Jabalameli ; Golnaz BanisadrSource :
- Advanced Biomedical Research [ 2277-9175 ] ; 2014.
Abstract
Preoperative assessment of anatomical landmarks andclinical factors help detect potentially difficult laryngoscopies. The aim of the present study was to compare the ability to predict difficult visualization of the larynx from thefollowing preoperative airway predictive indices, in isolation and combination: Neck circumference to thyromental distance (NC/TMD), neck circumference (NC), modified Mallampatitest (MMT), the ratio of height to thyromental distance (RHTMD), and the upper-lip-bite test (ULBT).
We collected data on657 consecutive patients scheduled for elective caesarean delivery under general anesthesia requiring endotracheal intubation and then evaluated all five factors before caesarean. An experienced anesthesiologist, not informed of the recorded preoperative airway evaluation, performed the laryngoscopy and grading (as per Cormack and Lehane's classification). Sensitivity, specificity, and positive and negative predictive values for each airway predictor in isolation and in combination were determined.
Difficult laryngoscopy (Grade 3 or 4) occurred in 53 (8.06%) patients. There were significant differences in thyromental distance (TMD), RHTMD, NC, and NC/TMD between difficult visualization of larynx and easy visualization of larynx patients (
The NC/TM Discomparable with NC, RHTMD, and ULBT for the prediction of difficult laryngoscopy in caes are an delivery.
Url:
DOI: 10.4103/2277-9175.142045
PubMed: 25337530
PubMed Central: 4202503
Links to Exploration step
PMC:4202503Le document en format XML
<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en">The predictive value of the ratio of neck circumference to thyromental distance in comparison with four predictive tests for difficult laryngoscopy in obstetric patients scheduled for caesarean delivery</title><author><name sortKey="Hirmanpour, Anahita" sort="Hirmanpour, Anahita" uniqKey="Hirmanpour A" first="Anahita" last="Hirmanpour">Anahita Hirmanpour</name><affiliation><nlm:aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</nlm:aff></affiliation></author><author><name sortKey="Safavi, Mohammadreza" sort="Safavi, Mohammadreza" uniqKey="Safavi M" first="Mohammadreza" last="Safavi">Mohammadreza Safavi</name><affiliation><nlm:aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</nlm:aff></affiliation></author><author><name sortKey="Honarmand, Azim" sort="Honarmand, Azim" uniqKey="Honarmand A" first="Azim" last="Honarmand">Azim Honarmand</name><affiliation><nlm:aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</nlm:aff></affiliation></author><author><name sortKey="Jabalameli, Mitra" sort="Jabalameli, Mitra" uniqKey="Jabalameli M" first="Mitra" last="Jabalameli">Mitra Jabalameli</name><affiliation><nlm:aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</nlm:aff></affiliation></author><author><name sortKey="Banisadr, Golnaz" sort="Banisadr, Golnaz" uniqKey="Banisadr G" first="Golnaz" last="Banisadr">Golnaz Banisadr</name><affiliation><nlm:aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</nlm:aff></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">PMC</idno><idno type="pmid">25337530</idno><idno type="pmc">4202503</idno><idno type="url">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4202503</idno><idno type="RBID">PMC:4202503</idno><idno type="doi">10.4103/2277-9175.142045</idno><date when="2014">2014</date><idno type="wicri:Area/Pmc/Corpus">002807</idno><idno type="wicri:explorRef" wicri:stream="Pmc" wicri:step="Corpus" wicri:corpus="PMC">002807</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a" type="main">The predictive value of the ratio of neck circumference to thyromental distance in comparison with four predictive tests for difficult laryngoscopy in obstetric patients scheduled for caesarean delivery</title><author><name sortKey="Hirmanpour, Anahita" sort="Hirmanpour, Anahita" uniqKey="Hirmanpour A" first="Anahita" last="Hirmanpour">Anahita Hirmanpour</name><affiliation><nlm:aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</nlm:aff></affiliation></author><author><name sortKey="Safavi, Mohammadreza" sort="Safavi, Mohammadreza" uniqKey="Safavi M" first="Mohammadreza" last="Safavi">Mohammadreza Safavi</name><affiliation><nlm:aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</nlm:aff></affiliation></author><author><name sortKey="Honarmand, Azim" sort="Honarmand, Azim" uniqKey="Honarmand A" first="Azim" last="Honarmand">Azim Honarmand</name><affiliation><nlm:aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</nlm:aff></affiliation></author><author><name sortKey="Jabalameli, Mitra" sort="Jabalameli, Mitra" uniqKey="Jabalameli M" first="Mitra" last="Jabalameli">Mitra Jabalameli</name><affiliation><nlm:aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</nlm:aff></affiliation></author><author><name sortKey="Banisadr, Golnaz" sort="Banisadr, Golnaz" uniqKey="Banisadr G" first="Golnaz" last="Banisadr">Golnaz Banisadr</name><affiliation><nlm:aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</nlm:aff></affiliation></author></analytic><series><title level="j">Advanced Biomedical Research</title><idno type="ISSN">2277-9175</idno><idno type="eISSN">2277-9175</idno><imprint><date when="2014">2014</date></imprint></series></biblStruct></sourceDesc></fileDesc><profileDesc><textClass></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en"><sec id="st1"><title>Background:</title><p>Preoperative assessment of anatomical landmarks andclinical factors help detect potentially difficult laryngoscopies. The aim of the present study was to compare the ability to predict difficult visualization of the larynx from thefollowing preoperative airway predictive indices, in isolation and combination: Neck circumference to thyromental distance (NC/TMD), neck circumference (NC), modified Mallampatitest (MMT), the ratio of height to thyromental distance (RHTMD), and the upper-lip-bite test (ULBT).</p></sec><sec id="st2"><title>Materials and Methods:</title><p>We collected data on657 consecutive patients scheduled for elective caesarean delivery under general anesthesia requiring endotracheal intubation and then evaluated all five factors before caesarean. An experienced anesthesiologist, not informed of the recorded preoperative airway evaluation, performed the laryngoscopy and grading (as per Cormack and Lehane's classification). Sensitivity, specificity, and positive and negative predictive values for each airway predictor in isolation and in combination were determined.</p></sec><sec id="st3"><title>Results:</title><p>Difficult laryngoscopy (Grade 3 or 4) occurred in 53 (8.06%) patients. There were significant differences in thyromental distance (TMD), RHTMD, NC, and NC/TMD between difficult visualization of larynx and easy visualization of larynx patients (<italic>P</italic> < 0.05). The main end-point area under curve (AUC) of the receiver-operating characteristic (ROC) was lower for MMT (AUC = 0.497; 95% Confidence Interval = CI,0.045-0.536) and ULBT (AUC = 0.500, 95% CI, 0.461-0.539) compared to RHTMD, NC, TMD, and NC/TMD score ([AUC = 0.627, 95% CI, 0.589-0.664], [AUC = 0.691; 95% CI, 0.654-0.726], [AUC = 0.606; 95% CI, 0.567-0.643], [AUC = 0.689;95% CI, 0.625-0.724], respectively), and the differences of six ROC curves were statistically significant (<italic>P</italic> < 0.05).</p></sec><sec id="st4"><title>Conclusion:</title><p>The NC/TM Discomparable with NC, RHTMD, and ULBT for the prediction of difficult laryngoscopy in caes are an delivery.</p></sec></div></front><back><div1 type="bibliography"><listBibl><biblStruct><analytic><author><name sortKey="Hawkins, Jl" uniqKey="Hawkins J">JL Hawkins</name></author><author><name sortKey="Koonin, Lm" uniqKey="Koonin L">LM Koonin</name></author><author><name sortKey="Palmer, Sk" uniqKey="Palmer S">SK Palmer</name></author><author><name sortKey="Gibbs, Cp" uniqKey="Gibbs C">CP Gibbs</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Palanisamy, A" uniqKey="Palanisamy A">A Palanisamy</name></author><author><name sortKey="Mitni, Aa" uniqKey="Mitni A">AA Mitni</name></author><author><name sortKey="Tsen, Lc" uniqKey="Tsen L">LC Tsen</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Randell, T" uniqKey="Randell T">T Randell</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Henderson, Jj" uniqKey="Henderson J">JJ Henderson</name></author><author><name sortKey="Popat, Mt" uniqKey="Popat M">MT Popat</name></author><author><name sortKey="Latto, Ip" uniqKey="Latto I">IP Latto</name></author><author><name sortKey="Pearce, Ac" uniqKey="Pearce A">AC Pearce</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Merah, Na" uniqKey="Merah N">NA Merah</name></author><author><name sortKey="Foullkes Crabbe, Dj" uniqKey="Foullkes Crabbe D">DJ Foullkes-Crabbe</name></author><author><name sortKey="Kushimo, Ot" uniqKey="Kushimo O">OT Kushimo</name></author><author><name sortKey="Ajayi, Pa" uniqKey="Ajayi P">PA Ajayi</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Boutonnet, M" uniqKey="Boutonnet M">M Boutonnet</name></author><author><name sortKey="Faitot, V" uniqKey="Faitot V">V Faitot</name></author><author><name sortKey="Keita, H" uniqKey="Keita H">H Keita</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Rao, Dp" uniqKey="Rao D">DP Rao</name></author><author><name sortKey="Rao, Va" uniqKey="Rao V">VA Rao</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Farcon, El" uniqKey="Farcon E">EL Farcon</name></author><author><name sortKey="Kim, Mh" uniqKey="Kim M">MH Kim</name></author><author><name sortKey="Marx, Gf" uniqKey="Marx G">GF Marx</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Arne, J" uniqKey="Arne J">J Arné</name></author><author><name sortKey="Descoins, P" uniqKey="Descoins P">P Descoins</name></author><author><name sortKey="Fusciardi, J" uniqKey="Fusciardi J">J Fusciardi</name></author><author><name sortKey="Ingrand, P" uniqKey="Ingrand P">P Ingrand</name></author><author><name sortKey="Ferrier, B" uniqKey="Ferrier B">B Ferrier</name></author><author><name sortKey="Boudigues, D" uniqKey="Boudigues D">D Boudigues</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Oates, Jd" uniqKey="Oates J">JD Oates</name></author><author><name sortKey="Macleod, Ad" uniqKey="Macleod A">AD Macleod</name></author><author><name sortKey="Oates, Pd" uniqKey="Oates P">PD Oates</name></author><author><name sortKey="Pearsall, Fj" uniqKey="Pearsall F">FJ Pearsall</name></author><author><name sortKey="Howie, Jc" uniqKey="Howie J">JC Howie</name></author><author><name sortKey="Murray, Gd" uniqKey="Murray G">GD Murray</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="El Ganzouri, Ar" uniqKey="El Ganzouri A">AR El-Ganzouri</name></author><author><name sortKey="Mccarthy, Rj" uniqKey="Mccarthy R">RJ McCarthy</name></author><author><name sortKey="Tuman, Kl" uniqKey="Tuman K">KL Tuman</name></author><author><name sortKey="Tanck, En" uniqKey="Tanck E">EN Tanck</name></author><author><name sortKey="Ivankovich, Ad" uniqKey="Ivankovich A">AD Ivankovich</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Naguib, M" uniqKey="Naguib M">M Naguib</name></author><author><name sortKey="Scamman, Fl" uniqKey="Scamman F">FL Scamman</name></author><author><name sortKey="O Ullivan, C" uniqKey="O Ullivan C">C O’sullivan</name></author><author><name sortKey="Aker, J" uniqKey="Aker J">J Aker</name></author><author><name sortKey="Ross, Af" uniqKey="Ross A">AF Ross</name></author><author><name sortKey="Kosmach, S" uniqKey="Kosmach S">S Kosmach</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Wilson, Me" uniqKey="Wilson M">ME Wilson</name></author><author><name sortKey="Spiegelhalter, D" uniqKey="Spiegelhalter D">D Spiegelhalter</name></author><author><name sortKey="Robertson, Ja" uniqKey="Robertson J">JA Robertson</name></author><author><name sortKey="Lesser, P" uniqKey="Lesser P">P Lesser</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Gonzalez, H" uniqKey="Gonzalez H">H Gonzalez</name></author><author><name sortKey="Minville, V" uniqKey="Minville V">V Minville</name></author><author><name sortKey="Delanoue, K" uniqKey="Delanoue K">K Delanoue</name></author><author><name sortKey="Mazerolles, M" uniqKey="Mazerolles M">M Mazerolles</name></author><author><name sortKey="Concina, D" uniqKey="Concina D">D Concina</name></author><author><name sortKey="Fourcade, O" uniqKey="Fourcade O">O Fourcade</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Khan, Zh" uniqKey="Khan Z">ZH Khan</name></author><author><name sortKey="Kashfi, A" uniqKey="Kashfi A">A Kashfi</name></author><author><name sortKey="Ebrahimkhani, E" uniqKey="Ebrahimkhani E">E Ebrahimkhani</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Eberhart, Lh" uniqKey="Eberhart L">LH Eberhart</name></author><author><name sortKey="Arndt, C" uniqKey="Arndt C">C Arndt</name></author><author><name sortKey="Cierpka, T" uniqKey="Cierpka T">T Cierpka</name></author><author><name sortKey="Schwanekamp, J" uniqKey="Schwanekamp J">J Schwanekamp</name></author><author><name sortKey="Wulf, H" uniqKey="Wulf H">H Wulf</name></author><author><name sortKey="Putzke, C" uniqKey="Putzke C">C Putzke</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Shiga, T" uniqKey="Shiga T">T Shiga</name></author><author><name sortKey="Wajima, Z" uniqKey="Wajima Z">Z Wajima</name></author><author><name sortKey="Inoue, T" uniqKey="Inoue T">T Inoue</name></author><author><name sortKey="Sakamoto, A" uniqKey="Sakamoto A">A Sakamoto</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Turkan, S" uniqKey="Turkan S">S Türkan</name></author><author><name sortKey="Ate, Y" uniqKey="Ate Y">Y Ateş</name></author><author><name sortKey="Cuhruk, H" uniqKey="Cuhruk H">H Cuhruk</name></author><author><name sortKey="Tekdemir, I" uniqKey="Tekdemir I">I Tekdemir</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Salimi, A" uniqKey="Salimi A">A Salimi</name></author><author><name sortKey="Farzanegan, B" uniqKey="Farzanegan B">B Farzanegan</name></author><author><name sortKey="Rastegarpour, A" uniqKey="Rastegarpour A">A Rastegarpour</name></author><author><name sortKey="Kolahi, Aa" uniqKey="Kolahi A">AA Kolahi</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Honarmand, A" uniqKey="Honarmand A">A Honarmand</name></author><author><name sortKey="Safavi, Mr" uniqKey="Safavi M">MR Safavi</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Safavi, M" uniqKey="Safavi M">M Safavi</name></author><author><name sortKey="Honarmand, A" uniqKey="Honarmand A">A Honarmand</name></author><author><name sortKey="Zare, N" uniqKey="Zare N">N Zare</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Samsoon, Gl" uniqKey="Samsoon G">GL Samsoon</name></author><author><name sortKey="Young, Jr" uniqKey="Young J">JR Young</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Savva, D" uniqKey="Savva D">D Savva</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Kim, Wh" uniqKey="Kim W">WH Kim</name></author><author><name sortKey="Ahn, Hj" uniqKey="Ahn H">HJ Ahn</name></author><author><name sortKey="Lee, Cj" uniqKey="Lee C">CJ Lee</name></author><author><name sortKey="Shin, Bs" uniqKey="Shin B">BS Shin</name></author><author><name sortKey="Ko, Js" uniqKey="Ko J">JS Ko</name></author><author><name sortKey="Choi, Sj" uniqKey="Choi S">SJ Choi</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Lewis, M" uniqKey="Lewis M">M Lewis</name></author><author><name sortKey="Keramati, S" uniqKey="Keramati S">S Keramati</name></author><author><name sortKey="Benumof, Jl" uniqKey="Benumof J">JL Benumof</name></author><author><name sortKey="Berry, Cc" uniqKey="Berry C">CC Berry</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Mallampati, Sr" uniqKey="Mallampati S">SR Mallampati</name></author><author><name sortKey="Gatt, Sp" uniqKey="Gatt S">SP Gatt</name></author><author><name sortKey="Gugino, Ld" uniqKey="Gugino L">LD Gugino</name></author><author><name sortKey="Desai, Sp" uniqKey="Desai S">SP Desai</name></author><author><name sortKey="Waraksa, B" uniqKey="Waraksa B">B Waraksa</name></author><author><name sortKey="Freiberger, D" uniqKey="Freiberger D">D Freiberger</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Birnbach, Dj" uniqKey="Birnbach D">DJ Birnbach</name></author><author><name sortKey="Browne, Im" uniqKey="Browne I">IM Browne</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Sellick, Ba" uniqKey="Sellick B">BA Sellick</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Cormack, Rs" uniqKey="Cormack R">RS Cormack</name></author><author><name sortKey="Lehane, J" uniqKey="Lehane J">J Lehane</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Krage, R" uniqKey="Krage R">R Krage</name></author><author><name sortKey="Van Rijn, C" uniqKey="Van Rijn C">C van Rijn</name></author><author><name sortKey="Van Groeningen, D" uniqKey="Van Groeningen D">D van Groeningen</name></author><author><name sortKey="Loer, Sa" uniqKey="Loer S">SA Loer</name></author><author><name sortKey="Schwarte, La" uniqKey="Schwarte L">LA Schwarte</name></author><author><name sortKey="Schober, P" uniqKey="Schober P">P Schober</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Schniederjans, Mj" uniqKey="Schniederjans M">MJ Schniederjans</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Hanley, Ja" uniqKey="Hanley J">JA Hanley</name></author><author><name sortKey="Mcneil, Bj" uniqKey="Mcneil B">BJ McNeil</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Calder, I" uniqKey="Calder I">I Calder</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Brodsky, Jb" uniqKey="Brodsky J">JB Brodsky</name></author><author><name sortKey="Lemmens, Hj" uniqKey="Lemmens H">HJ Lemmens</name></author><author><name sortKey="Brock Utne, Jg" uniqKey="Brock Utne J">JG Brock-Utne</name></author><author><name sortKey="Vierra, M" uniqKey="Vierra M">M Vierra</name></author><author><name sortKey="Saidman, Lj" uniqKey="Saidman L">LJ Saidman</name></author></analytic></biblStruct></listBibl></div1></back></TEI><pmc article-type="research-article"><pmc-dir>properties open_access</pmc-dir>
<front><journal-meta><journal-id journal-id-type="nlm-ta">Adv Biomed Res</journal-id><journal-id journal-id-type="iso-abbrev">Adv Biomed Res</journal-id><journal-id journal-id-type="publisher-id">ABR</journal-id><journal-title-group><journal-title>Advanced Biomedical Research</journal-title></journal-title-group><issn pub-type="ppub">2277-9175</issn><issn pub-type="epub">2277-9175</issn><publisher><publisher-name>Medknow Publications & Media Pvt Ltd</publisher-name><publisher-loc>India</publisher-loc></publisher></journal-meta><article-meta><article-id pub-id-type="pmid">25337530</article-id><article-id pub-id-type="pmc">4202503</article-id><article-id pub-id-type="publisher-id">ABR-3-200</article-id><article-id pub-id-type="doi">10.4103/2277-9175.142045</article-id><article-categories><subj-group subj-group-type="heading"><subject>Original Article</subject></subj-group></article-categories><title-group><article-title>The predictive value of the ratio of neck circumference to thyromental distance in comparison with four predictive tests for difficult laryngoscopy in obstetric patients scheduled for caesarean delivery</article-title></title-group><contrib-group><contrib contrib-type="author"><name><surname>Hirmanpour</surname><given-names>Anahita</given-names></name><xref ref-type="aff" rid="aff1"></xref></contrib><contrib contrib-type="author"><name><surname>Safavi</surname><given-names>Mohammadreza</given-names></name><xref ref-type="aff" rid="aff1"></xref><xref ref-type="corresp" rid="cor1"></xref></contrib><contrib contrib-type="author"><name><surname>Honarmand</surname><given-names>Azim</given-names></name><xref ref-type="aff" rid="aff1"></xref></contrib><contrib contrib-type="author"><name><surname>Jabalameli</surname><given-names>Mitra</given-names></name><xref ref-type="aff" rid="aff1"></xref></contrib><contrib contrib-type="author"><name><surname>Banisadr</surname><given-names>Golnaz</given-names></name><xref ref-type="aff" rid="aff1"></xref></contrib></contrib-group><aff id="aff1">Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</aff><author-notes><corresp id="cor1"><bold>Address for correspondence:</bold> Associate Prof. Mohammadreza Safavi, Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. E-mail: <email xlink:href="safavi@med.mui.ac.ir">safavi@med.mui.ac.ir</email></corresp></author-notes><pub-date pub-type="collection"><year>2014</year></pub-date><pub-date pub-type="epub"><day>30</day><month>9</month><year>2014</year></pub-date><volume>3</volume><elocation-id>200</elocation-id><history><date date-type="received"><day>08</day><month>10</month><year>2012</year></date><date date-type="accepted"><day>25</day><month>12</month><year>2012</year></date></history><permissions><copyright-statement>Copyright: © 2014 Hirmanpour.</copyright-statement><copyright-year>2014</copyright-year><license license-type="open-access" xlink:href="http://creativecommons.org/licenses/by-nc-sa/3.0"><license-p>This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.</license-p></license></permissions><abstract><sec id="st1"><title>Background:</title><p>Preoperative assessment of anatomical landmarks andclinical factors help detect potentially difficult laryngoscopies. The aim of the present study was to compare the ability to predict difficult visualization of the larynx from thefollowing preoperative airway predictive indices, in isolation and combination: Neck circumference to thyromental distance (NC/TMD), neck circumference (NC), modified Mallampatitest (MMT), the ratio of height to thyromental distance (RHTMD), and the upper-lip-bite test (ULBT).</p></sec><sec id="st2"><title>Materials and Methods:</title><p>We collected data on657 consecutive patients scheduled for elective caesarean delivery under general anesthesia requiring endotracheal intubation and then evaluated all five factors before caesarean. An experienced anesthesiologist, not informed of the recorded preoperative airway evaluation, performed the laryngoscopy and grading (as per Cormack and Lehane's classification). Sensitivity, specificity, and positive and negative predictive values for each airway predictor in isolation and in combination were determined.</p></sec><sec id="st3"><title>Results:</title><p>Difficult laryngoscopy (Grade 3 or 4) occurred in 53 (8.06%) patients. There were significant differences in thyromental distance (TMD), RHTMD, NC, and NC/TMD between difficult visualization of larynx and easy visualization of larynx patients (<italic>P</italic> < 0.05). The main end-point area under curve (AUC) of the receiver-operating characteristic (ROC) was lower for MMT (AUC = 0.497; 95% Confidence Interval = CI,0.045-0.536) and ULBT (AUC = 0.500, 95% CI, 0.461-0.539) compared to RHTMD, NC, TMD, and NC/TMD score ([AUC = 0.627, 95% CI, 0.589-0.664], [AUC = 0.691; 95% CI, 0.654-0.726], [AUC = 0.606; 95% CI, 0.567-0.643], [AUC = 0.689;95% CI, 0.625-0.724], respectively), and the differences of six ROC curves were statistically significant (<italic>P</italic> < 0.05).</p></sec><sec id="st4"><title>Conclusion:</title><p>The NC/TM Discomparable with NC, RHTMD, and ULBT for the prediction of difficult laryngoscopy in caes are an delivery.</p></sec></abstract><kwd-group><kwd>Caesarean delivery</kwd><kwd>difficult laryngoscopy</kwd><kwd>modified Mallampati test</kwd><kwd>neck circumference</kwd><kwd>neck circumference to thyromental distance</kwd><kwd>ratio of height to thyromental distance</kwd><kwd>upper-lip-bite test</kwd></kwd-group></article-meta></front><body><sec sec-type="intro" id="sec1-1"><title>INTRODUCTION</title><p>Although the use of general anesthesia for cesarean delivery has declined in these decades in parturient, it is still inevitable for management in several situations such as maternal hemorrhage, overt coagulopathy, fetal compromise (which is life-threatening), and patient refusal for regional anesthesia.[<xref rid="ref1" ref-type="bibr">1</xref>] Unanticipated difficulties with tracheal intubation in obstetrics remain a true challenge for anesthesiologists. Complications from general anesthesia for cesarean delivery are a leading cause of anesthesia-related mortality.[<xref rid="ref2" ref-type="bibr">2</xref>] The incidence of difficult larygoscopy or endothracheal intubation varies from 1.5% to 13% in patients undergoing general anesthesia.[<xref rid="ref2" ref-type="bibr">2</xref><xref rid="ref3" ref-type="bibr">3</xref><xref rid="ref4" ref-type="bibr">4</xref><xref rid="ref5" ref-type="bibr">5</xref><xref rid="ref6" ref-type="bibr">6</xref><xref rid="ref7" ref-type="bibr">7</xref>]</p><p>Most airway difficulties occur when they are not recognized before induction of anesthesia. Therefore, anesthesiologists must use their clinical skills to determine which patient will present difficulties with airway management.[<xref rid="ref8" ref-type="bibr">8</xref>] Many investigations have explained prediction criteria by applying single or multifactorial indexes.[<xref rid="ref9" ref-type="bibr">9</xref><xref rid="ref10" ref-type="bibr">10</xref><xref rid="ref11" ref-type="bibr">11</xref><xref rid="ref12" ref-type="bibr">12</xref><xref rid="ref13" ref-type="bibr">13</xref>]</p><p>Recently, Gonzalez <italic>et al</italic>.[<xref rid="ref14" ref-type="bibr">14</xref>] have demonstrated that the assessment of neck circumference (NC) preoperatively is defined as an important predicting factor for difficult intubation that measured the level of thyroid cartilage. Moreover, upper-lip-bite test (ULBT), which evaluates the possibility of a patient to cover the mucosa of the upper lip with the lower incisors, is an acceptable option for predicting difficult intubation as a simple, single test.[<xref rid="ref15" ref-type="bibr">15</xref><xref rid="ref16" ref-type="bibr">16</xref><xref rid="ref17" ref-type="bibr">17</xref><xref rid="ref18" ref-type="bibr">18</xref><xref rid="ref19" ref-type="bibr">19</xref>]</p><p>Another test for difficult laryngoscopy is the ratio of height to thyromental distance (RHTMD = Height [cm]/TMD[cm]). RHTMD measurement has high sensitivity than other tests and is sufficiently sensitive to detect possible difficulties with laryngoscopy and intubation.[<xref rid="ref20" ref-type="bibr">20</xref><xref rid="ref21" ref-type="bibr">21</xref>]</p><p>The Mallampati classification of mouth opening and the Samsoon and Young modified system[<xref rid="ref22" ref-type="bibr">22</xref>] have been shown to change during pregnancy. A pre-pregnancy classification of I-II may advance one or two classes due to changes in pregnancy.[<xref rid="ref23" ref-type="bibr">23</xref>] In addition, Savva[<xref rid="ref23" ref-type="bibr">23</xref>] showed that), modified Mallampatitest (MMT) was neither sensitive nor specific enough as a single test in predicting difficult intubation in parturient patients.</p><p>Another study by Kim <italic>et al</italic>.[<xref rid="ref24" ref-type="bibr">24</xref>] has demonstrated that the ratio of neck circumference to thyromental distance (NC/TMD) was a better indicator than the other established methods for predicting difficult laryngoscopy in obese patients.</p><p>No published study has compared NC with ULBT, RHTMD, MMT, and NC/TMD by their sensitivity, specificity, and positive and negative predictive values for prediction of difficult laryngoscopy in pregnant patients.</p><p>Therefore, this study was designed to develop predictors for difficult intubation and to compare these indices with established indices in parturient candidates for cesarean delivery.</p></sec><sec sec-type="materials|methods" id="sec1-2"><title>MATERIALS AND METHODS</title><p>This prospective observational study was approved by an institutional Ethics Committee of our university and all patients provided informed and written consent. A total of 657 consecutive American Society of Anesthesiologists (ASA) physical status I and II adult patients who were undergoing cesarean delivery under general anesthesia with tracheal intubation during the 18-month period were enrolled.</p><p>Patients with a history of trauma to the airway or cranial, cervical and facial regions, or were edentulous or requiring awake intubation, patients with restricted motility of the neck and mandible (e.g., cervical disc disorders or rheumatoid arthritis) and inability to sit were not included in the study.</p><p>Patients’ data collected included age, weight, height, and body mass index (BMI). A senior anesthesiologist with at least 8-year experience in anesthesia, who was not informed of the preoperative classes carried out laryngoscopy and evaluated difficulty at intubation.</p><p>The subsequent five predictive test measurements were performed on all patients:</p><p><list list-type="bullet"><list-item><p>NC: NC was determined at the level of thyroid cartilage in cm[<xref rid="ref14" ref-type="bibr">14</xref><xref rid="ref22" ref-type="bibr">22</xref>]</p></list-item><list-item><p>ULBT: ULBT was introduced according to the following criteria: Class I if the incisors can bite the upper lip above the vermilion line, class II if the lower incisors could bite the upper lip below the vermilion line, and class III if the lower incisors could not bite the upper lip[<xref rid="ref15" ref-type="bibr">15</xref>]</p></list-item><list-item><p>RHTMD: Thyromental distance (TMD) was measured from the bony point of the mentum while the head was extended completely with closed mouth.[<xref rid="ref25" ref-type="bibr">25</xref>] Then the ratio of height to TMD was calculated</p></list-item><list-item><p>MMT: Samsoon and Young's modification of Mallampati test[<xref rid="ref22" ref-type="bibr">22</xref>] showed oropharyngeal structures visible upon maximal mouth opening. Each patient was asked to open her mouth maximally and to protrude the tongue without phonation while she was seated.[<xref rid="ref26" ref-type="bibr">26</xref>] The view was classified as follows: Class I: Good visualization of the soft palate, fauces, uvula, and tonsillar pillars; class II: Pillars obscured by the base of the tongue but soft palate, fauces, and uvula visible; class III: Soft palate and base of uvula visible; and class IV: Soft palate not visible[<xref rid="ref22" ref-type="bibr">22</xref>]</p></list-item><list-item><p>NC/TMD: This is a new predictor of difficult intubation in obese patients[<xref rid="ref24" ref-type="bibr">24</xref>] where in the neck was measured at the level of cricoid cartilage and TMD is the distance from the thyroid notch to the mentum in centimeter.</p></list-item></list></p><p>In the operating theatre, each patient was monitored routinely with an electrocardiogram, noninvasive arterial blood pressure, and peripheral oxygen saturation. Patients breathed high-flow oxygen through a facemask for about 3-5 min or four vital capacity breaths.[<xref rid="ref27" ref-type="bibr">27</xref>] Anesthesia was then induced with sodium thiopental (5 mg/kg) i.v., and suxamethonium chloride (2 mg/kg) i.v. was administered for facilitating endothracheal intubation. During loss of consciousness, cricoids pressure as described by Sellick[<xref rid="ref28" ref-type="bibr">28</xref>] was applied to the patients. Whenever the fasciculations disappeared, the parturient head was placed in the ‘sniffing position’. All tracheal intubations were performed by an 8-year experienced anesthesiologist who was not informed of the preoperative classes and assessed the difficulty of laryngoscopy at intubation. For the first laryngoscopy in each case, a size three Macintosh laryngoscope blade was used.</p><p>The laryngoscopic view was classified according to the Cormack and Lahane scale as follows:[<xref rid="ref29" ref-type="bibr">29</xref><xref rid="ref30" ref-type="bibr">30</xref>] grade I: Vocal cords were completely visible; grade II: only the arythnoids were visible; grade III: Only the epiglottis was visible; and grade IV: The epiglottis was not visible.</p><p>Difficult larygoscopy or difficult visualization of larynx (DVL) has been defined as the visibility of the larynx corresponding to grades III and IV in classification of Cormack and Lehane, and grades I and II on direct laryngoscopy are defined as easy visualization of larynx (EVL). The Sellick maneuver was maintained until the trachea was intubated and the cuff inflated and confirmed successful intubation by bilateral auscultation of lungs and capnography.</p><p>A prospective power analysis showed that assuming an incidence of DVL of 5%, 600 patients provided a power of more than 80% to detect an improvement of discriminating power measured by the area under curve (AUC) of the appropriate receiver-operating characteristic (ROC) curve of an absolute value of 15% (e.g. from 50% to 65%) with a type I error of 5% and using a two-sided alternative hypothesis.</p><p>A list of these measures is provided in the <xref ref-type="app" rid="App1">Appendix</xref> together with a short description and instructions on how to perform the calculations. The AUC was used as themain end-point of the study to decide whether the score was clinically useful. An ROC plot was obtained by calculating the sensitivity (true-positive fraction) and specificity (true-negative fraction) of every observed data value (cut-off value), and plotting sensitivity against 1-specificity (false-positive fraction). A value of 0.5 under the ROC curve indicated that the variable performs no better than chance and a value of 1.0 indicates perfect discrimination. A larger area under the ROC curve represents more reliability[<xref rid="ref31" ref-type="bibr">31</xref><xref rid="ref32" ref-type="bibr">32</xref>] and good discrimination of the scoring system. Differences between the AUC values of all predictive tests were calculated, and a <italic>P</italic> value of 0.05 was defined as statistically significant.</p><p>Patient data were presented as mean ± SD BMI, determined from weight (kg)/height 2(m). Patient data and value of the airway predictors were compared using <italic>t</italic>-tests for continuous variables and U-test for MMT or ULBT. Sensitivity, specificity, and Positive predictive value PPV were obtained and compared amongst predictors. The data were analyzed using SPSS version 18.0.</p></sec><sec sec-type="results" id="sec1-3"><title>RESULTS</title><p>A total of 657 parturient patients were included in this study. Patients’ age, height, weight, and BMI are shown in <xref ref-type="table" rid="T1">Table 1</xref>. There were 596 ASA I and 61 ASA II patients. DVL was observed in 53 (8.6%) patients. There was no failed intubation. There were significant differences in weight and BMI between DVL and ELV patients [<xref ref-type="table" rid="T1">Table 1</xref>].</p><table-wrap id="T1" position="float"><label>Table 1</label><caption><p>Patient characteristics</p></caption><graphic xlink:href="ABR-3-200-g001"></graphic></table-wrap><p>The distributions of ASA, MMT, ULBT, and the Cormack and Lehane grades are presented in <xref ref-type="table" rid="T2">Table 2</xref>.</p><table-wrap id="T2" position="float"><label>Table 2</label><caption><p>Distribution of American Society of Anesthesiologists, modified mallampati class, upper lip bite test, and laryngoscopic view of all patients</p></caption><graphic xlink:href="ABR-3-200-g002"></graphic></table-wrap><p>Significant differences were observed in TMD, RHTMD, NC, and NC/TMD between DVL and EVL patients using the U-test [<xref ref-type="table" rid="T3">Table 3</xref>]. The measures used to explain the predictive properties of the four models are shown in <xref ref-type="table" rid="T4">Table 4</xref>.</p><table-wrap id="T3" position="float"><label>Table 3</label><caption><p>Demographic data of patients in difficult and easy laryngoscopic view groups</p></caption><graphic xlink:href="ABR-3-200-g003"></graphic></table-wrap><table-wrap id="T4" position="float"><label>Table 4</label><caption><p>Predictive value for modified mallampati test, upper lip bite test, ratio of height to thyromental distance, neck circumference, and neck circumference to thyromental distance to predict the occurrence of a grade 3 or 4 intubation according to the modified cormack-lehane classification</p></caption><graphic xlink:href="ABR-3-200-g004"></graphic></table-wrap><p>The main end-point of this study, the AUC of the ROC, was lower for MMT (AUC = 0.497; 95% CI,0.045-0.536) and ULBT (AUC = 0.500, 95% CI, 0.461-0.539) compared to RHTMD, NC, TMD, and NC/TMD scores ([AUC = 0.627, 95% CI, 0.589-0.664], [AUC = 0.691; 95% CI, 0.654-0.726], [AUC = 0.606; 95% CI, 0.567-0.643], [AUC = 0.689;95% CI, 0.625-0.724], respectively), and the differences of six ROC curves were statistically significant (<italic>P</italic> < 0.05). Predictive values of the six single or combined predictors are shown in Tables <xref ref-type="table" rid="T4">4</xref> and <xref ref-type="table" rid="T5">5</xref>.</p><table-wrap id="T5" position="float"><label>Table 5</label><caption><p>Comparison of receiver-operating characteristic curves</p></caption><graphic xlink:href="ABR-3-200-g005"></graphic></table-wrap><p>Using discrimination analysis, MMT grade > I, ULBT ≥ grade 2, RHTMD > 28.83, NC > 39.5, TMD ≥ 5, and NC/TMD > 5.6 were considered as the cut-off points for predicting difficulty in laryngoscopy. The RHTMD was the least sensitive of the single tests with a sensitivity of 26.4%. ULBT and NC/TMD had the highest sensitivities amongst single predictors (100% and 71.1%, respectively). After RHTMD, NC and NC/TMD had the highest accuracy and positive predictive values. The multivariate analysis odds ratio (95% CI) of MMT, ULBT, RHTMD, NC, and NC/TMD were 0.67, (0.36-1.23) 1.01, (0.55-1.84) 6.41, (3.16-13.01) 7.85 (4.32-14.24), and 5.96 (3.20-11.12), respectively.</p></sec><sec sec-type="discussion" id="sec1-4"><title>DISCUSSION</title><p>In this study, the incidence of DVL was found to be 8.6%. Honarmand <italic>et al</italic>.[<xref rid="ref20" ref-type="bibr">20</xref>] showed a similar incidence of DVL in obstetrics (8.7%). In another recent literature by Boutonnet <italic>et al</italic>.,[<xref rid="ref6" ref-type="bibr">6</xref>] performed to evaluate the anesthetic practices in obstetrics, the incidence of difficult intubation was found to be 3.3%. Another study by Merah <italic>et al</italic>.[<xref rid="ref5" ref-type="bibr">5</xref>] showed an incidence of 10% in difficult laryngoscopy in a Nigerian parturient. We can describe this variation in incidence of DVL to factors such as different anthropometric features among the population, cricoids pressure application, head position, or degree of muscle relaxation.[<xref rid="ref33" ref-type="bibr">33</xref>] In parturient patients, because of the gaining weight associated with pregnancy, the visibility of observing the larynx reduces.[<xref rid="ref34" ref-type="bibr">34</xref>] This fact is supported by our finding of a relation between reduced laryngoscopic view and weight and NC.</p><p>Failed tracheal intubation with inability to maintain an open airway and adequate oxygenation is one of the main and most frequent causes of anesthesia-related maternal mortality and morbidity.[<xref rid="ref4" ref-type="bibr">4</xref>] Thus, studies for predictive test that has accuracy and applicability for prediction difficult intubation continue. Not only RHTMD, but also NC and NC/TMD seem to have these quality factors and they are easy to perform as a bedside test.</p><p>Analysis of our data showed that the AUC of ROC for RHTMD, NC, and NC/TMD were 0.627, 0.691, and 0.689, respectively, whereas the AUC for MMT and ULBT were only 0.497 and 0.500, respectively. The accuracy of NC and NC/TMD for preoperative prediction of difficult laryngoscopy in non-obstetric patients was documented by Gonzalez[<xref rid="ref14" ref-type="bibr">14</xref>] and Kim <italic>et al</italic>.,[<xref rid="ref24" ref-type="bibr">24</xref>] studies. In this study, we found that RHTMD, NC, and NC/TMD were the most useful predictors with specificities of 95.2, 89.07, and 70.2 and accuracies of 89.2, 85.8, and 70.3, respectively. The advantage of NC/TMD is its higher sensitivity than the other two tests, thus minimizing false-negative (3.4%) predictions. Because difficult laryngoscopy is infrequent, the incidence of false negative is also small.</p><p>Moreover, the likelihood ratio (LR+) for a positive test result may be a useful measure to judge the usefulness of a predictive tool in practice.[<xref rid="ref33" ref-type="bibr">33</xref>] This measure is the number of times more likely that a patient with a positive test result will present with difficult intubation. The LR+ was 5.5 for RHTMD, 4.49 for NC, and 2.41 for NC/TMD, whereas it was 1.14 and 1 for MMT and ULBT, respectively.</p><p>Using the multivariate analysis, we found that NC, RHTMD, and NC/TMD have the highest odds ratio for prediction of difficult laryngoscopy. We found that NC > 39.5, RHTMD > 28.83, and NC/TMD > 5.6 were determining factors in predicting a poor laryngeal view for parturient patients. Our result confirms the Gonzalez[<xref rid="ref14" ref-type="bibr">14</xref>] and Brodsky[<xref rid="ref34" ref-type="bibr">34</xref>] study that NC at the level of thyroid cartilage is a valuable predictor of difficult laryngoscopy in obese patients, as shown in the parturient in our study. Gonzalez[<xref rid="ref14" ref-type="bibr">14</xref>] showed NC > 43 is an important predicting factor for determining difficult intubation in obese patients (males and females); our results showed NC >39.5 to be an indicator of difficult larygoscopy in obstetrics. This difference in our study is because patients BMI that BMI = 46 ± 12 in defined for obese patients with intubation difficulty scale (IDS >5); however, in our study, BMI = 32.2 ± 5.5 was defined for DVL in obstetrics (<italic>P</italic> = 0.017).</p><p>RHTMD > 28.83 (sensitivity = 26.42%, specificity = 95.2%) was considered as a predictor for difficult intubation in our study; however, in Honarmand's[<xref rid="ref20" ref-type="bibr">20</xref>] study it was considered to be >21.24 (sensitivity = 71.4, specificity = 98.1%). This difference can be due to the RHTMD calculation on accurate measurement of patients’ TMD and height made by variation in observers.[<xref rid="ref10" ref-type="bibr">10</xref>]</p><p>This study was designed to develop a predictor for difficult intubation that is simple and easy to use at the bedside compared with established indices; we found that NC/TMD >5.6 (sensitivity = 71.7%, specificity = 70.2%) showed a moderate to fair sensitivity, specificity, negative predictive value, and a relatively large AUC on the ROC curve, which revealed that NC/TMD is highly predictive. A study by Kim <italic>et al</italic>.[<xref rid="ref24" ref-type="bibr">24</xref>] found NC/TMD ≥5 to be a good predictor of difficult intubation; however, their study had some limitations. We included only elective surgical patients while excluding emergency cases in our study. Moreover, our conclusion is not applicable to all subgroups of the general population, such as obeseor tooth less patients.</p></sec><sec sec-type="conclusion" id="sec1-5"><title>CONCLUSION</title><p>We found that difficult intubation was associated with TMD, increasing NC, RHTMD, and the ratio of NC/TMD. This study supports the use of assessing NC/TMD preoperatively to predict a potentially difficult intubation as an easy and simple test.</p></sec></body><back><ack><title>ACKNOWLEDGMENT</title><p>The authors wish to sincerely thank the support of all the colleagues in Beheshti Hospital Medical Center affiliated to Isfahan University of Medical Sciences in Isfahan, Iran. Furthermore, our special thanks go to the patients, who whole heartedly and actively assisted us in carrying out this research. No conflict of interest existed. This prospective randomized observational study was approved by the Ethics Committee of our university (Isfahan University of Medical Sciences) and all patients gave written, informed consent.</p></ack><fn-group><fn fn-type="supported-by"><p><bold>Source of Support:</bold> Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran</p></fn><fn fn-type="conflict"><p><bold>Conflict of Interest:</bold> None declared.</p></fn></fn-group><app-group><app id="App1"><title>APPENDIX</title><sec id="sec1-6"><title>STATISTICAL TERMS AND DEFINITIONS</title><p><list list-type="bullet"><list-item><p>True positive: A difficult laryngoscopy that had been predicted to be difficult (A)</p></list-item><list-item><p>False positive: An easy laryngoscopy that had been predicted to be difficult (B)</p></list-item><list-item><p>True negative: An easy laryngoscopy that had been predicted to be easy (D)</p></list-item><list-item><p>False negative: A difficult laryngoscopy that had been predicted to be easy (C)</p></list-item><list-item><p>Sensitivity: The percentage of correctly predicted difficult laryngoscopies as a proportion of all laryngoscopies that were truly difficult (A/(A + C))</p></list-item><list-item><p>Specificity: The percentage of correctly predicted easy laryngoscopies as a proportion of all laryngoscopies that were truly easy (D/(B + D)</p></list-item><list-item><p>Positive predictive value: The percentage of correctly predicted difficult laryngoscopies as a proportion of all predicted difficult laryngoscopies (A/(A + B))</p></list-item><list-item><p>Negative predictive value: The percentage of correctly predicted easy laryngoscopies as a proportion of all predicted easy laryngoscopies (D/(C + D))</p></list-item><list-item><p>Accuracy: The percentage of correctly predicted easy or difficult laryngoscopies as a proportion of all laryngoscopies (A + D)/(A + B + C + D)</p></list-item><list-item><p>Likelihood ratio of a positive test result (LR+): The number of times more likely that a patient with positive test result will have a difficult airway; it is calculated by sensitivity divided by 1-specificity.’ AUC of an ROC-curve (area under a receiver operating characteristic curve): The probability of the correct classification using the test in a sample pair of two patients (one with an easy airway, one with a difficult airway). In this specialized case the AUC= (sensitivity* (1-specificity)/2) + (sensitivity* specificity) + ((1-sensitivity)* specificity/2)</p></list-item></list></p></sec></app></app-group><ref-list><title>REFERENCES</title><ref id="ref1"><label>1</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Hawkins</surname><given-names>JL</given-names></name><name><surname>Koonin</surname><given-names>LM</given-names></name><name><surname>Palmer</surname><given-names>SK</given-names></name><name><surname>Gibbs</surname><given-names>CP</given-names></name></person-group><article-title>Anesthesia-related deaths during obstetric delivery in the United States, 1979-1990</article-title><source>Anesthesiology</source><year>1997</year><volume>86</volume><fpage>277</fpage><lpage>84</lpage><pub-id pub-id-type="pmid">9054245</pub-id></element-citation></ref><ref id="ref2"><label>2</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Palanisamy</surname><given-names>A</given-names></name><name><surname>Mitni</surname><given-names>AA</given-names></name><name><surname>Tsen</surname><given-names>LC</given-names></name></person-group><article-title>General anesthesia for cesarean delivery at a tertiary care hospital from 2000 to 2005: A retrospective analysis and 10-year update</article-title><source>Int J Obstet Anesth</source><year>2011</year><volume>20</volume><fpage>6</fpage><lpage>10</lpage></element-citation></ref><ref id="ref3"><label>3</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Randell</surname><given-names>T</given-names></name></person-group><article-title>Prediction of difficult intubation</article-title><source>Acta Anesthesiol Scand</source><year>1996</year><volume>40</volume><fpage>1016</fpage><lpage>23</lpage></element-citation></ref><ref id="ref4"><label>4</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Henderson</surname><given-names>JJ</given-names></name><name><surname>Popat</surname><given-names>MT</given-names></name><name><surname>Latto</surname><given-names>IP</given-names></name><name><surname>Pearce</surname><given-names>AC</given-names></name></person-group><collab>Difficult Airway Society</collab><article-title>Difficult Airway Society guidelines for management of the unanticipated difficult intubation</article-title><source>Anaesthesia</source><year>2004</year><volume>59</volume><fpage>675</fpage><lpage>94</lpage><pub-id pub-id-type="pmid">15200543</pub-id></element-citation></ref><ref id="ref5"><label>5</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Merah</surname><given-names>NA</given-names></name><name><surname>Foullkes-Crabbe</surname><given-names>DJ</given-names></name><name><surname>Kushimo</surname><given-names>OT</given-names></name><name><surname>Ajayi</surname><given-names>PA</given-names></name></person-group><article-title>Prediction of difficult laryngoscopy in a population of Nigerian obstetric patients</article-title><source>West Afr J Med</source><year>2004</year><volume>23</volume><fpage>38</fpage><lpage>41</lpage><pub-id pub-id-type="pmid">15171524</pub-id></element-citation></ref><ref id="ref6"><label>6</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Boutonnet</surname><given-names>M</given-names></name><name><surname>Faitot</surname><given-names>V</given-names></name><name><surname>Keita</surname><given-names>H</given-names></name></person-group><article-title>Airway management in obstetrics</article-title><source>Ann Fr Anesth Reanim</source><year>2011</year><volume>30</volume><fpage>651</fpage><lpage>64</lpage><pub-id pub-id-type="pmid">21705176</pub-id></element-citation></ref><ref id="ref7"><label>7</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Rao</surname><given-names>DP</given-names></name><name><surname>Rao</surname><given-names>VA</given-names></name></person-group><article-title>Morbidly obese parturient: Challenges for the anaesthesiologist, including managing the difficult airway in obstetrics. What is new?</article-title><source>Indian J Anaesth</source><year>2010</year><volume>54</volume><fpage>508</fpage><lpage>21</lpage><pub-id pub-id-type="pmid">21224967</pub-id></element-citation></ref><ref id="ref8"><label>8</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Farcon</surname><given-names>EL</given-names></name><name><surname>Kim</surname><given-names>MH</given-names></name><name><surname>Marx</surname><given-names>GF</given-names></name></person-group><article-title>Changing Mallampati score during labour</article-title><source>Can J Anaesth</source><year>1994</year><volume>41</volume><fpage>50</fpage><lpage>1</lpage><pub-id pub-id-type="pmid">8111943</pub-id></element-citation></ref><ref id="ref9"><label>9</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Arné</surname><given-names>J</given-names></name><name><surname>Descoins</surname><given-names>P</given-names></name><name><surname>Fusciardi</surname><given-names>J</given-names></name><name><surname>Ingrand</surname><given-names>P</given-names></name><name><surname>Ferrier</surname><given-names>B</given-names></name><name><surname>Boudigues</surname><given-names>D</given-names></name><etal></etal></person-group><article-title>Preoperative assessment for difficult intubation in general and ENT surgery: Predictive value of a clinical multivariate risk index</article-title><source>Br J Anaesth</source><year>1998</year><volume>80</volume><fpage>140</fpage><lpage>6</lpage><pub-id pub-id-type="pmid">9602574</pub-id></element-citation></ref><ref id="ref10"><label>10</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Oates</surname><given-names>JD</given-names></name><name><surname>Macleod</surname><given-names>AD</given-names></name><name><surname>Oates</surname><given-names>PD</given-names></name><name><surname>Pearsall</surname><given-names>FJ</given-names></name><name><surname>Howie</surname><given-names>JC</given-names></name><name><surname>Murray</surname><given-names>GD</given-names></name></person-group><article-title>Comparison of two methods for predicting difficult intubation</article-title><source>Br J Anaesth</source><year>1991</year><volume>66</volume><fpage>305</fpage><lpage>9</lpage><pub-id pub-id-type="pmid">2015145</pub-id></element-citation></ref><ref id="ref11"><label>11</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>El-Ganzouri</surname><given-names>AR</given-names></name><name><surname>McCarthy</surname><given-names>RJ</given-names></name><name><surname>Tuman</surname><given-names>KL</given-names></name><name><surname>Tanck</surname><given-names>EN</given-names></name><name><surname>Ivankovich</surname><given-names>AD</given-names></name></person-group><article-title>Preoperative airway assessment: Predictive value of a multivariative risk index</article-title><source>Anesth Analg</source><year>1997</year><volume>84</volume><fpage>419</fpage><lpage>21</lpage><pub-id pub-id-type="pmid">9024040</pub-id></element-citation></ref><ref id="ref12"><label>12</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Naguib</surname><given-names>M</given-names></name><name><surname>Scamman</surname><given-names>FL</given-names></name><name><surname>O’sullivan</surname><given-names>C</given-names></name><name><surname>Aker</surname><given-names>J</given-names></name><name><surname>Ross</surname><given-names>AF</given-names></name><name><surname>Kosmach</surname><given-names>S</given-names></name><etal></etal></person-group><article-title>Predictive performance of three multivariate difficult tracheal intubation models: A double-blind, case-controlled study</article-title><source>Anesth Analg</source><year>2006</year><volume>102</volume><fpage>818</fpage><lpage>24</lpage><pub-id pub-id-type="pmid">16492835</pub-id></element-citation></ref><ref id="ref13"><label>13</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Wilson</surname><given-names>ME</given-names></name><name><surname>Spiegelhalter</surname><given-names>D</given-names></name><name><surname>Robertson</surname><given-names>JA</given-names></name><name><surname>Lesser</surname><given-names>P</given-names></name></person-group><article-title>Predicting difficult intubation</article-title><source>Br J Anaesth</source><year>1988</year><volume>61</volume><fpage>211</fpage><lpage>6</lpage><pub-id pub-id-type="pmid">3415893</pub-id></element-citation></ref><ref id="ref14"><label>14</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Gonzalez</surname><given-names>H</given-names></name><name><surname>Minville</surname><given-names>V</given-names></name><name><surname>Delanoue</surname><given-names>K</given-names></name><name><surname>Mazerolles</surname><given-names>M</given-names></name><name><surname>Concina</surname><given-names>D</given-names></name><name><surname>Fourcade</surname><given-names>O</given-names></name></person-group><article-title>The importance of increased neck circumference to intubation difficulties in obese patients</article-title><source>Anesth Analg</source><year>2008</year><volume>106</volume><fpage>1132</fpage><lpage>6</lpage><pub-id pub-id-type="pmid">18349184</pub-id></element-citation></ref><ref id="ref15"><label>15</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Khan</surname><given-names>ZH</given-names></name><name><surname>Kashfi</surname><given-names>A</given-names></name><name><surname>Ebrahimkhani</surname><given-names>E</given-names></name></person-group><article-title>A comparison of the upper lip bite test (a simple new technique) with modified Mallampati classification in predicting difficulty in endotracheal intubation: A prospective blinded study</article-title><source>Anesth Analg</source><year>2003</year><volume>96</volume><fpage>595</fpage><lpage>9</lpage><pub-id pub-id-type="pmid">12538218</pub-id></element-citation></ref><ref id="ref16"><label>16</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Eberhart</surname><given-names>LH</given-names></name><name><surname>Arndt</surname><given-names>C</given-names></name><name><surname>Cierpka</surname><given-names>T</given-names></name><name><surname>Schwanekamp</surname><given-names>J</given-names></name><name><surname>Wulf</surname><given-names>H</given-names></name><name><surname>Putzke</surname><given-names>C</given-names></name></person-group><article-title>The reliability and validity of the upper lip bite test compared with the Mallampati classification to predict difficult laryngoscopy: An external prospective evaluation</article-title><source>Anesth Analg</source><year>2005</year><volume>101</volume><fpage>284</fpage><lpage>9</lpage><pub-id pub-id-type="pmid">15976247</pub-id></element-citation></ref><ref id="ref17"><label>17</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Shiga</surname><given-names>T</given-names></name><name><surname>Wajima</surname><given-names>Z</given-names></name><name><surname>Inoue</surname><given-names>T</given-names></name><name><surname>Sakamoto</surname><given-names>A</given-names></name></person-group><article-title>Predicting difficult intubation in apparently normal patients: A meta-analysis of bedside screening test performance</article-title><source>Anesthesiology</source><year>2005</year><volume>103</volume><fpage>429</fpage><lpage>37</lpage><pub-id pub-id-type="pmid">16052126</pub-id></element-citation></ref><ref id="ref18"><label>18</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Türkan</surname><given-names>S</given-names></name><name><surname>Ateş</surname><given-names>Y</given-names></name><name><surname>Cuhruk</surname><given-names>H</given-names></name><name><surname>Tekdemir</surname><given-names>I</given-names></name></person-group><article-title>Should we reevaluate the variables for predicting the difficult airway in anesthesiology?</article-title><source>Anesth Analg</source><year>2002</year><volume>94</volume><fpage>1340</fpage><lpage>4</lpage><pub-id pub-id-type="pmid">11973217</pub-id></element-citation></ref><ref id="ref19"><label>19</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Salimi</surname><given-names>A</given-names></name><name><surname>Farzanegan</surname><given-names>B</given-names></name><name><surname>Rastegarpour</surname><given-names>A</given-names></name><name><surname>Kolahi</surname><given-names>AA</given-names></name></person-group><article-title>Comparison of the upper lip bite test with measurement of thyromental distance for prediction of difficult intubations</article-title><source>Acta Anaesthesiol Taiwan</source><year>2008</year><volume>46</volume><fpage>61</fpage><lpage>5</lpage><pub-id pub-id-type="pmid">18593650</pub-id></element-citation></ref><ref id="ref20"><label>20</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Honarmand</surname><given-names>A</given-names></name><name><surname>Safavi</surname><given-names>MR</given-names></name></person-group><article-title>Prediction of difficult laryngoscopy in obstetric patients scheduled for Caesarean delivery</article-title><source>Eur J Anaesthesiol</source><year>2008</year><volume>25</volume><fpage>714</fpage><lpage>20</lpage><pub-id pub-id-type="pmid">18471331</pub-id></element-citation></ref><ref id="ref21"><label>21</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Safavi</surname><given-names>M</given-names></name><name><surname>Honarmand</surname><given-names>A</given-names></name><name><surname>Zare</surname><given-names>N</given-names></name></person-group><article-title>A comparison of the ratio of patient's height to thyromental distance with the modified Mallampati and the upper lip bite test in predicting difficult laryngoscopy</article-title><source>Saudi J Anaesth</source><year>2011</year><volume>5</volume><fpage>258</fpage><lpage>63</lpage><pub-id pub-id-type="pmid">21957403</pub-id></element-citation></ref><ref id="ref22"><label>22</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Samsoon</surname><given-names>GL</given-names></name><name><surname>Young</surname><given-names>JR</given-names></name></person-group><article-title>Difficult tracheal intubation: A retrospective study</article-title><source>Anaesthesia</source><year>1987</year><volume>42</volume><fpage>487</fpage><lpage>90</lpage><pub-id pub-id-type="pmid">3592174</pub-id></element-citation></ref><ref id="ref23"><label>23</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Savva</surname><given-names>D</given-names></name></person-group><article-title>Prediction of difficult tracheal intubation</article-title><source>Br J Anaesth</source><year>1994</year><volume>73</volume><fpage>149</fpage><lpage>53</lpage><pub-id pub-id-type="pmid">7917726</pub-id></element-citation></ref><ref id="ref24"><label>24</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Kim</surname><given-names>WH</given-names></name><name><surname>Ahn</surname><given-names>HJ</given-names></name><name><surname>Lee</surname><given-names>CJ</given-names></name><name><surname>Shin</surname><given-names>BS</given-names></name><name><surname>Ko</surname><given-names>JS</given-names></name><name><surname>Choi</surname><given-names>SJ</given-names></name><etal></etal></person-group><article-title>Neck circumference to thyromental distance ratio: A new predictor of difficult intubation in obese patients</article-title><source>Br J Anaesth</source><year>2011</year><volume>106</volume><fpage>743</fpage><lpage>8</lpage><pub-id pub-id-type="pmid">21354999</pub-id></element-citation></ref><ref id="ref25"><label>25</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Lewis</surname><given-names>M</given-names></name><name><surname>Keramati</surname><given-names>S</given-names></name><name><surname>Benumof</surname><given-names>JL</given-names></name><name><surname>Berry</surname><given-names>CC</given-names></name></person-group><article-title>What is the best way to determine oropharyngeal classification and mandibular space length to predict difficult laryngoscopy?</article-title><source>Anesthesiology</source><year>1994</year><volume>81</volume><fpage>69</fpage><lpage>75</lpage><pub-id pub-id-type="pmid">8042812</pub-id></element-citation></ref><ref id="ref26"><label>26</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Mallampati</surname><given-names>SR</given-names></name><name><surname>Gatt</surname><given-names>SP</given-names></name><name><surname>Gugino</surname><given-names>LD</given-names></name><name><surname>Desai</surname><given-names>SP</given-names></name><name><surname>Waraksa</surname><given-names>B</given-names></name><name><surname>Freiberger</surname><given-names>D</given-names></name><etal></etal></person-group><article-title>A clinical sign to predict difficult tracheal intubation: A prospective study</article-title><source>Can Anaesth Soc J</source><year>1985</year><volume>32</volume><fpage>429</fpage><lpage>34</lpage><pub-id pub-id-type="pmid">4027773</pub-id></element-citation></ref><ref id="ref27"><label>27</label><element-citation publication-type="book"><person-group person-group-type="author"><name><surname>Birnbach</surname><given-names>DJ</given-names></name><name><surname>Browne</surname><given-names>IM</given-names></name></person-group><person-group person-group-type="editor"><name><surname>Miller</surname><given-names>RD</given-names></name></person-group><article-title>Anesthesia for obstetrics</article-title><source>Textbook of Anesthesia</source><year>2010</year><publisher-loc>Philadelphia</publisher-loc><publisher-name>Churchil Livingstone Co</publisher-name><fpage>2221</fpage></element-citation></ref><ref id="ref28"><label>28</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Sellick</surname><given-names>BA</given-names></name></person-group><article-title>Cricoid pressure to control regurgitation of stomach contents during induction of anaesthesia</article-title><source>Lancet</source><year>1961</year><volume>2</volume><fpage>404</fpage><lpage>6</lpage><pub-id pub-id-type="pmid">13749923</pub-id></element-citation></ref><ref id="ref29"><label>29</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Cormack</surname><given-names>RS</given-names></name><name><surname>Lehane</surname><given-names>J</given-names></name></person-group><article-title>Difficult tracheal intubation in obstetrics</article-title><source>Anaesthesia</source><year>1984</year><volume>39</volume><fpage>1105</fpage><lpage>11</lpage><pub-id pub-id-type="pmid">6507827</pub-id></element-citation></ref><ref id="ref30"><label>30</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Krage</surname><given-names>R</given-names></name><name><surname>van Rijn</surname><given-names>C</given-names></name><name><surname>van Groeningen</surname><given-names>D</given-names></name><name><surname>Loer</surname><given-names>SA</given-names></name><name><surname>Schwarte</surname><given-names>LA</given-names></name><name><surname>Schober</surname><given-names>P</given-names></name></person-group><article-title>Cormack-Lehane classification revisited</article-title><source>Br J Anaesth</source><year>2010</year><volume>105</volume><fpage>220</fpage><lpage>7</lpage><pub-id pub-id-type="pmid">20554633</pub-id></element-citation></ref><ref id="ref31"><label>31</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Schniederjans</surname><given-names>MJ</given-names></name></person-group><article-title>Mathematical partitioning of the receiver operating curve: A diagnostic tool for medical decision making</article-title><source>Socioecon Plann Sci</source><year>1985</year><volume>19</volume><fpage>125</fpage><lpage>35</lpage></element-citation></ref><ref id="ref32"><label>32</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Hanley</surname><given-names>JA</given-names></name><name><surname>McNeil</surname><given-names>BJ</given-names></name></person-group><article-title>The meaning and use of the area under a receiver operating characteristic (ROC) curve</article-title><source>Radiology</source><year>1982</year><volume>143</volume><fpage>29</fpage><lpage>36</lpage><pub-id pub-id-type="pmid">7063747</pub-id></element-citation></ref><ref id="ref33"><label>33</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Calder</surname><given-names>I</given-names></name></person-group><article-title>Useless ritual?</article-title><source>Anaesthesia</source><year>2002</year><volume>57</volume><fpage>612</fpage><pub-id pub-id-type="pmid">12071167</pub-id></element-citation></ref><ref id="ref34"><label>34</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Brodsky</surname><given-names>JB</given-names></name><name><surname>Lemmens</surname><given-names>HJ</given-names></name><name><surname>Brock-Utne</surname><given-names>JG</given-names></name><name><surname>Vierra</surname><given-names>M</given-names></name><name><surname>Saidman</surname><given-names>LJ</given-names></name></person-group><article-title>Morbid obesity and tracheal intubation</article-title><source>Anesth Analg</source><year>2002</year><volume>94</volume><fpage>732</fpage><lpage>6</lpage><pub-id pub-id-type="pmid">11867407</pub-id></element-citation></ref></ref-list></back></pmc></record>Pour manipuler ce document sous Unix (Dilib)
EXPLOR_STEP=$WICRI_ROOT/Wicri/Santé/explor/EdenteV2/Data/Pmc/Corpus
HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 002807 | SxmlIndent | more
Ou
HfdSelect -h $EXPLOR_AREA/Data/Pmc/Corpus/biblio.hfd -nk 002807 | SxmlIndent | more
Pour mettre un lien sur cette page dans le réseau Wicri
{{Explor lien
|wiki= Wicri/Santé
|area= EdenteV2
|flux= Pmc
|étape= Corpus
|type= RBID
|clé= PMC:4202503
|texte= The predictive value of the ratio of neck circumference to thyromental distance in comparison with four predictive tests for difficult laryngoscopy in obstetric patients scheduled for caesarean delivery
}}
Pour générer des pages wiki
HfdIndexSelect -h $EXPLOR_AREA/Data/Pmc/Corpus/RBID.i -Sk "pubmed:25337530" \
| HfdSelect -Kh $EXPLOR_AREA/Data/Pmc/Corpus/biblio.hfd \
| NlmPubMed2Wicri -a EdenteV2
| This area was generated with Dilib version V0.6.32. |  |