Recent clinical studies have demonstrated that high blood lactate in the prehospital setting and poor lactate clearance in the emergency department are predictive of in-hospital mortality. This analysis of data collected from a swine model of hemorrhage and restricted volume resuscitation investigated the hypotheses that noninvasive muscle pH (pHm) and H⁺ clearance would predict mortality, and the responses would be similar between pHm and lactate. Data from a set of 57 swine were analyzed over the first 2 h after controlled hemorrhage and uncontrolled splenic bleeding. Surviving animals were ones that lived for the full 5-h experimental period. Venous lactate was determined at baseline, shock, and at 30, 60, and 120 min after injury. Spectra were collected continuously from the posterior thigh using a prototype CareGuide 1100 Oximeter and pHm calculated from the spectra; H⁺ concentration was determined from pHm. Lactate clearance rate was calculated from the difference in lactate concentration at 120 min and shock, and H⁺ clearance was calculated in a similar manner. Comparison of the area under the receiver operator characteristic curves was used to assess prediction of survival at 5 h after injury. At 120 min after injury, lactate, lactate clearance, noninvasive pHm, and noninvasive H⁺ clearance were equivalent predictors of mortality each with a receiver operator characteristic area under the curve of 0.87. Thresholds for single lactate (<3.8 mmol/L) or pHm (>7.30) determinations were found to be consistent with a resuscitation goal targeted to reverse acidosis. Continuous, noninvasive pHm monitoring may provide a substitute for lactate measurement in trauma patients, particularly in the prehospital and emergency department settings.