Background:Tracheal intubation is a common procedure performed on critically ill patients. In these patients, there is a high risk of life-threatening complications associated with the procedure, with severe hypoxemia being one of the more common. Development of severe hypoxemia, in turn, increases the risk of post-intubation cardiac arrest. Therefore, optimal preoxygenation is an essential part of tracheal intubation to help stave off subsequent complications.
Both NIV and HFNC can provide a higher fraction of inspired oxygen than standard oxygen therapies. HFNC can provide continuous oxygen up to 70L/min via nasal prongs with the potential advantage of remaining in place for apneic oxygenation. NIV can also provide high flow oxygen but must be removed during the apneic phase of intubation. To date there has not been a study comparing NIV vs HFNC to reduce the incidence of severe hypoxemia during intubation until now; the FLORALI-2 trial....Read More
Background: Rapid Sequence Intubation (RSI) is a common procedure performed by both emergency clinicians and intensivists. Although the procedure is complex, the major pieces are pre-oxygenation, administration of a sedative agent in close proximity with a paralytic, laryngoscopy and placement of an endotracheal tube without the provision of any ventilations during the process. The avoidance of bag-mask ventilations (BMV), or any positive pressure breaths, rests on the belief that those breaths can distend the stomach and lead to regurgitation and aspiration. For this to happen, the force of the breath must exceed the pressure of the lower esophageal sphincter (~ 20 mm Hg). Critically ill patients presenting with airway compromise cannot be guaranteed to have a fasting state, regurgitation and aspiration is a major concern.
However, there’s another side to this. Many of our patients who are critically ill have intrapulmonary shunting; portions of the lung are atelectatic, filled with fluid, blood, or pus and not being oxygenated though they are being perfused. Blood running through these portions of the lung will be deoxygenated and will lower the overall O2 content of blood entering the systemic circulation after mixing with blood coming from ventilated regions. This shunting at least partially explains why we see patients rapidly desaturating during intubation. Positive pressure can recruit atelectatic portions of the lung that are not involved in gas exchange thus decreasing the physiologic shunt and increasing the patient’s oxygen reserve.
Despite decades of experience with RSI we continue to look for better approaches since the procedure still poses serious risks to the patient. Recent modifications that have seen wide adoption include using the bed-up-head-elevated (BUHE) position, suction assisted laryngoscopy for airway decontamination (SALAD) and bougie first intubation, though there are many more. Now, a publication in the NEJM makes us question the core principle of BMV during RSI....Read More