Bag-Mask Ventilation vs Intubation During Cardiopulmonary Resuscitation
Several large studies have demonstrated increased mortality with endotracheal intubation (ETI) during cardiopulmonary resuscitation (CPR). Ventilation by bag valve mask (BVM) is purported to possess certain advantages, namely, being easier to initiate, interfering less with cardiac massage, and appearing to be associated with few significant complications.
A recent and succinctly named study published in JAMA in February of 2018 titled “Effect of Bag-Mask Ventilation vs Endotracheal Intubation During Cardiopulmonary Resuscitation on Neurological Outcome After Out-of-Hospital Cardiorespiratory Arrest A Randomized Clinical Trial” attempted to delineate whether BVM was not inferior to ETI during CPR using favorable neurological outcomes at 28 days as a primary endpoint.
Using a multicenter non-inferiority randomized design, Jabre et al. enrolled twenty physician-staffed pre-hospital emergency medical services (EMS) located throughout France and Belgium. Patients were enrolled if they were eighteen years of age or older with an out of hospital cardiac arrest and excluded if pregnant, incarcerated or if massive gastric aspiration was suspected. Once the physician staffed EMS crews arrived on scene, patients in cardiac arrest were randomized to the BVM group or ETI group and treatment was initiated. Importantly, physicians could intervene at anytime during the airway procedure and patients were intubated once return of spontaneous circulation (ROSC) was achieved.Over a period of 22 months, 2043 patients were enrolled and randomized to either BVM or ETI groups. After randomization, patients were followed for 28 days and neurological outcome was measured by the Glasgow Pittsburgh Cerebral Performance Categories scale. Several secondary endpoints were recorded including survival at hospital admission/discharge/28 days, difficulty of intubation, rates of ROSC, complications of BVM and interruption of chest compressions.
With respect to the primary endpoint, favorable neurologic outcome at 28 days was found to be 4.3% in the BVM group and 4.2% in the ETI group, falling far short of the assigned non-inferiority margin. A subsequent test of difference did not demonstrate inferiority of BVM when compared with ETI. Notable secondary endpoints included higher rates of ROSC in the ETI group (38.9% vs. 34.2%) and higher rates of complications in the BVM group, 15.2% of patients regurgitated compared to a 7.7% in the ETI group.
In other words, BVM was not inferior but was also not non-inferior to ETI making this an inconclusive study. So what can the average emergency physician practicing in the U.S. take away from this publication? I would argue very little. Aside from possible under-powering (which was virtually unavoidable), this was a well-designed and executed study. However, in the event the non-inferiority margin was achieved, vast differences in EMS systems would severely limited generalization to an EMS system without a physician. This study also includes only patients in cardiac arrest which comprise only a portion of patients requiring positive pressure ventilation in the field. In summary, while this paper is not a practice altering publication, it contributes to a growing body of literature favoring less invasive treatment modalities in the pre-hospital setting. In EMS, there is a colloquial dichotomy of “stay and play” or “load and go”. In resource rich settings with short transport times, I would argue that getting the patient to definitive care quickly should take priority over intubating in a cramped bathroom or at the bottom of a dark basement stairwell.