From the Guidelines
A bag-valve mask (BVM) should not be used for patients with suspected herniation as it can worsen the condition. When managing a patient with a suspected herniation, it is crucial to prioritize proper airway management and ventilation techniques to prevent further complications. According to the American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1, if the airway cannot be opened with a jaw thrust, a head tilt–chin lift should be used to establish a patent airway. However, in cases of suspected herniation, controlled ventilation with specific parameters is recommended to prevent hyperventilation and provide adequate oxygenation.
- Key considerations include:
- Respiratory rate of 10-12 breaths per minute
- Tidal volume of 6-8 mL/kg
- Maintaining PaCO2 between 30-35 mmHg This approach is supported by the guidelines, which advise against routine hyperventilation, even in cases of head injury, and suggest that intentional brief hyperventilation may be used as a temporizing rescue therapy if there are signs of impending brain herniation 1. Manual ventilation with a BVM often leads to inconsistent volumes and rates, making it difficult to maintain the precise ventilation needed for these critical patients. Endotracheal intubation should be performed before initiating controlled ventilation in herniation cases to ensure proper airway management.
From the Research
Bad Valve Mask for Herniation
- The use of a bad valve mask can lead to increased intracranial pressure, which may result in herniation 2.
- Studies have shown that mannitol is effective in reducing intracranial pressure, and its effectiveness is proportional to the degree of intracranial hypertension 3, 4.
- However, the use of a bad valve mask is not directly related to the treatment of intracranial hypertension or herniation.
- A study on the effects of face mask ventilation in apneic patients found that a resuscitation ventilator is at least as effective as traditional bag-valve-mask or face mask resuscitation in controlled elective surgery patients 5.
- In the context of herniation, it is crucial to maintain or re-establish adequate cerebral blood flow, and osmotherapy, such as mannitol, is considered the mainstay of medical therapy 2.
- The dose-response relationship between mannitol and intracranial pressure is not fully understood, and more research is needed to determine the optimal dosage 4.
- Other therapies, such as hyperventilation and ventriculostomy drainage, may also be used to lower intracranial pressure after traumatic brain injury 6.