Early worst central venous oxygen saturation is predictive of mortality in severe head trauma but not in moderate head trauma

Abstract

Introduction The aim of the present study was to evaluate the mortality prediction power of central venous oxygen saturation (ScVO2) in critically ill patients suffering from major trauma and head trauma. Methods In an ED, eight-bed, ICU of a teaching hospital from January 2004 to November 2007, all patients with major trauma (RTS < 10) and head trauma were included in the study. On the basis of the severity of head trauma the patients were divided into two groups: severe (GCS ≤ 8; n = 91) and moderate head trauma (GCS > 8 ≤ 12; n = 116). Each group was in turn divided into two other groups: patient survivors and dead patients. In each subgroup, the age, sex, ISS, SAPS II, worst ScVO2 on the first day from trauma (emogasanalysis of venous blood sampled by a catheter inserted in the superior vena cava 2 hours from trauma), and worst lactate level in circulating blood on the first day from trauma were compared. Statistics were performed with the Student t test and the χ2 test. Results The results showing a significant difference are summarized in Table 1. Table 1 Severe head trauma Moderate head trauma Survivors (n = 76) Dead (n = 15) Survivors (n = 99) Dead (n = 17) ISS (pt) 30.3 ± 10.7 43.4 ± 18° 27.9 ± 16 41.1 ± 16.3° 71 ± 7 62 ± 9* 73 ± 7 75 ± 7 ScVO2 (%) Lactate (mmol/l) 3.5 ± 1.9 9 ± 5.4° 2.9 ± 1.6 6.1 ± 4° Data presented as the mean ± SD. *P < 0.05, °P < 0.01. Conclusion ScVO2 seems to be predictive of major outcome in severe head trauma but not in moderate head trauma. Venous mixing of the superior vena cava could play a role in this difference.