Transcutaneous oxygen and CO2 as early warning of tissue hypoxia and hemodynamic shock in critically ill emergency patients.

Abstract

Although cardiac and pulmonary function can be measured precisely, evaluation of tissue perfusion remains elusive because it usually is inferred from subjective symptoms and imprecise signs of shock. The latter are indirect criteria used to assess the overall circulatory status as well as tissue perfusion but are not direct quantitative measures of perfusion. However, noninvasive transcutaneous oxygen (PtcO2) and carbon dioxide (PtcCO2) tensions, which directly measure skin oxygenation and CO2 retention, may be used to objectively evaluate skin oxygenation and perfusion in emergency patients beginning with resuscitation immediately after hospital admission. This study was a preliminary evaluation of tissue oxygenation and perfusion by objective PtcO2 and PtcCO2 patterns in severely injured surviving and nonsurviving patients; specifically, the aim was to describe time patterns that may be used as early warning signs of circulatory dysfunction and death. Prospective descriptive study of a consecutive series of severely injured emergency patients. University-affiliated Level I trauma center and intensive care unit. Forty-eight consecutive severely injured patients were prospectively monitored by PtcO2 and PtcCO2 sensors immediately after emergency admission. Compared with survivors, patients who died had significantly lower PtcO2 and higher PtcCO2 values beginning with the early stage of resuscitation. All patients who maintained PtcO2 >150 torr (19.99 kPa) throughout monitoring survived. Periods of PtcO2 <50 torr (6.66 kPa) for >60 mins or PtcCO2 >60 torr (8.00 kPa) for >30 mins were associated with 90% mortality and 100% morbidity. PtcO2 and PtcCO2 monitoring continuously evaluate tissue perfusion and serve as early warning in critically injured patients during resuscitation immediately after hospital admission.