NEW YORK (Reuters Health) – Interruption of cardiopulmonary resuscitation (CPR) compressions is common and prolonged when paramedics attempt to perform endotracheal intubation at the same time, research indicates.
Decreased interruption of chest compressions in out-of-hospital cardiac arrest is strongly associated with increased survival, the study authors note in the Annals of Emergency Medicine for November.
“Animal studies suggest that even brief pauses (3 to 5 seconds) may impair CPR coronary perfusion,” they write. Pauses to insert an endotracheal tube – not always the easiest maneuver – may therefore increase mortality.
Still, paramedics in the U.S. perform endotracheal intubation in almost all cases of out-of-hospital cardiopulmonary arrest.
“While we teach paramedics to intubate quickly and with a single attempt, we had no objective observations of intubation efforts,” lead author Dr. Henry E. Wang told Reuters Health. “Similarly, while there is emphasis on maintaining continuous CPR chest compressions, there were no studies identifying the causes of CPR interruptions. This study represented a ‘perfect scientific storm,’ enabling us to simultaneously shed light on both important questions.”
In cooperation with 2 EMS agencies (1 urban and 1 rural), the research team set up portable cardiac monitors to record clinical and digital audio data during 100 resuscitations of adult patients. Paramedics used conventional endotracheal intubation-based advanced airway management strategies.
Dr. Wang, who is now at the University of Alabama at Birmingham, and associates at the University of Pittsburgh report that compressions were interrupted by a median of 2 attempts (range 1 to 9) at tracheal intubation for a median of 110 seconds. Almost one-third of pauses exceeded one minute, and more than 25% exceeded 3 minutes. In some cases, the interruptions accounted for as much as 7 minutes.
CPR pauses related to intubation attempts accounted for approximately 23% of all CPR interruptions.
The authors suggest that one way to reduce CPR interruptions would be to alter out-of-hospital airway management techniques.
Dr. Wang explained: “Intubation involves the use of a metal laryngoscope to open the mouth and expose the vocal cords; the paramedic then tries to insert a plastic breathing tube ‘bulls-eye’ through the vocal cords. In contrast, the King LT and Combitube are inserted blindly into the mouth without visualizing the vocal cords. Most experts think that King LTs and Combitubes are easier to learn and insert. They also appear to provide comparable ventilation.”
“We need a randomized trial comparing endotracheal intubation with King/Combitube insertion in cardiac arrest,” he added. “We continue to seek a network of EMS agencies brave enough to take on this tough question.”
Another potential strategy is to delay intubation until later in resuscitation attempts.
Editorialists from the University of Arizona in Tucson, Drs. Bentley J. Bobrow and Daniel W. Spaite, recommend: “For at least the first 5 to 10 minutes of resuscitation, providers should prevent interruptions of chest compressions for anything other than single defibrillatory attempts and intentionally delay tracheal intubation before return of spontaneous circulation.”
Ann Emerg Med 2009;54:645-655.