As early airway support is pivotal for stabilization of a child after TBI, the control of ventilation has been the subject of controversy for many years. Fundamentally, hyperventilation leads to decreased CBF (1 mmHg change in partial pressure of carbon dioxide in the arterial blood [PaCO2] decreases CBF by 3% in regions of intact autoregulation), which ultimately leads to decreased cerebral blood volume (and decreased ICP based on the Munro–Kellie doctrine). However, the determination of the balance between adequate blood flow (and blood volume) to support neurological function while minimizing excessive flow has been very difficult over the past several decades. Bruce and colleagues demonstrated that a protocol that included aggressive hyperventilation led to good neurological outcome in children after TBI, with the rationale for this approach that excessive CBF (or hyperemia) was common. Contradicting this assumption, Adelson and colleagues reported that a significant percentage of children had cerebral hypoperfusion (CBF < 20 ml/100g/min) early after injury, and others demonstrated that routine hyperventilation could induce brain ischemia.[24–27] As a result, brief periods of hyperventilation are now recommended to treat acute neurologic deterioration, including signs of impending brain herniation (pupillary dilation, hypertension and/or bradycardia) as other therapies are being instituted. In addition, longer periods of aggressive hyperventilation may be appropriate for refractory intracranial hypertension when CBF is known to be increased or when all other therapies have failed. However, routine, severe hyperventilation seems to represent a significant risk for brain hypoxia. In summary, it appears clear that acute hyperventilation (of duration substantial enough to allow interventions to treat a catastrophic event) is occasionally warranted, while routine hyperventilation has substantial risks and limited defined benefit.
Pediatr Health. 2009;3(6):533-541. © 2009 Future Medicine Ltd.
Cite this: Emergency Treatment Options for Pediatric Traumatic Brain Injury - Medscape - Dec 01, 2009.