List the indications for and contraindications to the use of non-invasive ventilation in acute respiratory failure.
Non-invasive ventilation usually encompasses face mask (full or nasal) CPAP with or without additional ventilatory support
Indications can be based on physiology or on specific aetiological cause:
1. Desire to provide increased respiratory support without the need for endotracheal intUbation.
The respiratory support make take the form of: ·
• increased FI(closed circuit)
• increased End Expiratory Pressure, or
• increased inspiratory pressure (as continuous positive airway pressure or additional inspiratory support in the form of pressure or volume assisted breaths)
2. Desire to. delay or prevent the complications and morbidity associated with mechanical ventilatory support via an endotracheal tube.
The specific types of respiratory failure that may benefit from Non-Invasive Ventilation should be listed (ideally with some indication of the level of evidence in the published literature to support the approach).
Conditions that may benefit include:
• Hypercapnic respiratory failure:
- . acute exacerbation of COPD, post-extubation acute respiratory failure, respiratory failure in patients with cystic fibrosis, patients awaiting lung-transplantation, patients who are not candidates for intubation (eg. DNR?, terminal illness).
• Hypoxaemic respiratory failure
- cardiogenic pulmonary oedema, postoperative respiratory failure, post-traumatic respiratory failure, respiratory failure in AIDS, patients who are not candidates for intubation.
A list of contraindications should include those situations that make the potential disadvantages or complications of non invasive ventilation worse. Differentiation into absolute and relative is arbitrary.
• lack of experience in technique (technical & mechanical problems), intubation required for other reasons including airway protection and sputum clearance, uncooperative patients (confused, comatose, reluctant), full stomach (risks of aspiration), local trauma (nose/face),
fractured base of skull, oesophageal surgery (risks of gastric/oesophageal insufflation)
A model answer might benefit from point form:
- Pulmonary oedema
- Lung infection in the neutropenic patient
- weaning from invasive ventilation
- prevention/avoidance of intubation
- decreased level of consciousness
- vomiting, high aspiration risk
- facial trauma
- hemodynamic instability, particularly poor preload states