Prehospital Trauma Life Support (PHTLS) Practice Test

What is the best ventilation rate for a patient demonstrating decerebrate posturing with a GCS score of 4?

1. 10 breaths per minute

2. 20 breaths per minute

3. 30 breaths per minute

4. 35 breaths per minute

The correct answer is: 20 breaths per minute

In managing a patient with a Glasgow Coma Scale (GCS) score of 4, which indicates a severe impairment of consciousness and significant neurological compromise, it is critical to ensure adequate ventilation. Decerebrate posturing, characterized by extension of the arms and legs, may accompany serious brain injury or dysfunction, necessitating the need for aggressive airway management and controlled ventilation. The best ventilation rate in this situation is aimed at ensuring sufficient oxygenation and preventing hypercapnia (excessive carbon dioxide), which can further exacerbate neurological injury. A rate of 20 breaths per minute is generally considered a balanced approach, providing adequate minute ventilation while avoiding the risks associated with excessive ventilation, which can lead to respiratory alkalosis and potential worsening of cerebral perfusion by constricting cerebral blood vessels. A ventilation rate of 10 breaths per minute would likely be insufficient to maintain adequate oxygenation in such a compromised patient, while rates of 30 or 35 breaths per minute may cause overventilation, adversely affecting the patient's overall condition. Thus, 20 breaths per minute strikes the right balance between adequate ventilation and the prevention of potential complications associated with rapid ventilation.