Shock Index, Serum Lactate Level, and Arterial-End Tidal Carbon Dioxide Difference as Hospital Mortality Markers and Guidelines of Early Resuscitation in Hypovolemic Shock

ABSTRACT

PURPOSE: To determine whether differences in arterial and end-tidal carbon dioxide [P(a-et)CO2], shock index, and serum lactate levels are helpful for predicting the outcome of resuscitation in hypovolemic shock patients in the emergency department. METHODS: A prospective study of end-tidal carbon dioxide (EtCO2)-derived variables and patient outcomes in hypovolemic shock was conducted in the emergency department of a university hospital from January 2005 to February 2006. A total of fifty-eight hypovolemic shock patients over 20 years old were included. During resuscitation, patients received volume replacement including blood transfusions, as well as vasopressor or inotropic therapy if needed. RESULTS: Twenty-one patients died in the hospital. At the time of admission (hour 0) and after resuscitation (hour 4), there were no differences related to age, respiration and heart rate, CVP, arterial blood gases, or EtCO2 between survivors and non-survivors. Non-survivors had significantly higher shock index scores, serum lactate levels, and P(a-et) CO2 than the survivors. The Receiver operator characteristic (ROC) curves at hour 4 hour for P(a-et)CO2 were as effective for predicting mortality as were the shock index and serum lactate levels. Shock index > 1.0, P(a-et)CO2 > 4 mmHg, and serum lactate > 5.0 mmol/L after resuscitation were all associated with a high early mortality rate (p=0.074, 0.001, 0.000, respectively). CONCLUSION: P(a-et)CO2, shock index, and serum lactate levels are predictive of in-hospital mortality and may be useful as guidelines in the resuscitation of hypovolemic shock patients in the emergency department.