CBF and CBF/PCO2 reactivity in childhood strangulation

Four children with self-inflicted strangulation injuries had cerebral blood flow determined by stable xenon computed tomography (XeCTCBF) within 24 hours of admission. All had suffered a severe hypoxic-ischemic cerebral injury; 3 initially had fixed pupils, all were apneic with varying bradyarrhythmias, and the initial mean arterial pH was 7.26 (+/- 0.18). The initial blood glucose values were greater than 300 mg/dl (334 and 351 mg/dl) in the 2 patients who died compared to the 2 who survived (104 and 295 mg/dl). The cardiac index was depressed during the first several days of hospitalization in the 2 patients who died (less than 2.0 L/min/m2) compared to the 2 who survived. Total CBF was normal (63 +/- 8 ml/min/100 gm) and local variations in CBF were present. PCO2 reactivity was determined by hyperventilating the 4 patients for 20 min from an end tidal PCO2 of 39 +/- 3 torr to 29 +/- 1 torr and then repeating the XeCTCBF study. Marked regional variability in the CBF/PCO2 response was observed, ranging from 0.5-5.5 ml/min/100 gm/torr PCO2. In the 2 patients who died, the CBF/PCO2 was decreased (1.2 ml/min/100 gm/torr PCO2) compared to the 2 patients who survived (2.1 ml/min/100 gm/torr PCO2). Although CBF was normal in these 4 children, the hyperventilation response was depressed, variable, and even paradoxical which may be important in the evolution of further brain injury and is a critical factor in deciding whether hyperventilation may be of clinical benefit.(ABSTRACT TRUNCATED AT 250 WORDS)