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CBF and CBF/PCO2 reactivity in childhood strangulation
S Ashwal1, R M Perkin, J R Thompson
1Department of Pediatrics, Loma Linda University School of Medicine, California 92350.
Insights
Cerebral blood flow (CBF) was normal in children with strangulation injuries, but their response to hyperventilation was impaired. This variability in CBF/PCO2 reactivity may worsen brain injury.
Area of Science:
- Pediatric neurology
- Neurocritical care
- Cerebral blood flow dynamics
Background:
- Strangulation injuries in children can lead to severe hypoxic-ischemic brain injury.
- Assessing cerebral blood flow (CBF) is crucial for managing these patients.
- Stable xenon computed tomography (XeCTCBF) is a method for determining CBF.
Observation:
- Four children with strangulation injuries underwent XeCTCBF within 24 hours of admission.
- All patients exhibited signs of severe hypoxic-ischemic cerebral injury, including apnea and bradyarrhythmias.
- Initial blood glucose and cardiac index values differed between survivors and non-survivors.
Findings:
- Total CBF was normal in all four children, with regional variations present.
- PCO2 reactivity, assessed via hyperventilation, showed marked regional variability.
- The CBF/PCO2 response was reduced in the two non-survivors compared to the survivors.
Implications:
- Despite normal CBF, impaired and variable PCO2 reactivity suggests potential for further brain injury.
- These findings highlight the importance of assessing CBF/PCO2 response in managing strangulation injuries.
- Understanding these dynamics is critical for determining the clinical utility of hyperventilation therapy.
Abstract:
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)