By Joshua Guttman, MD
Clattenburg EJ, Wroe P, Brown S, et al. Point-of-care ultrasound use in patients with cardiac arrest is associated prolonged cardiopulmonary resuscitation pauses: A prospective cohort study. Resuscitation. 2018 Jan;122:65-68.
Point of Care Ultrasound (POCUS) has become standard during cardiac arrest in order to diagnose reversible conditions such as pericardial tamponade or to prognosticate such as evaluation of cardiac standstill. Because adequate views are difficult to obtain with ongoing chest compressions, the POCUS is generally performed during pauses for pulse and rhythm checks. Previous small studies suggested that performance of POCUS leads to prolonged CPR pauses which may be of detriment to the patient. The authors performed a prospective observational study on patients presenting to a single urban ED in cardiac arrest or who experienced cardiac arrest in the ED, who had video recordings of the resuscitation. Exclusions included traumatic arrests and patients who had less than 2 CPR pauses performed. Authors analyzed the video recordings to determine length of pauses, who was performing the POCUS, reason for pause, if POCUS was performed during the pause and who was the code leader. The primary outcome was the difference in length of pause between pauses that had POCUS performed and pauses without POCUS.
The authors analyzed 24 videos. They found that pauses with POCUS were a mean of 19 seconds and pauses without POCUS were a mean of 14 seconds. The authors considered pauses over 3 seconds significant, based on previous research. The authors found that if the same person leading the code also performed the POCUS, then pause was even more prolonged (6 seconds). If the physician performing the POCUS was ultrasound fellowship trained, then the pause was 4 seconds shorter than physicians without ultrasound fellowship training. The authors conclude by suggesting that timers be utilized to limit pause duration.
This was a small but well performed study examining a common scenario in every ED. Utilization video review is likely the most feasible way of reviewing CPR pauses and the authors took adequate steps to ensure that there was consensus among multiple video reviewers for all their outcome measures. The data is consistent with previous research on the topic. It is probably of no surprise to those of us who witness POCUS being performed during real time cardiac arrest, especially when residents perform the POCUS. At this point, despite the low volume of patients in these studies, given the plausibility and consistency of the results, research efforts should move towards evaluating methods of reducing pauses associated with POCUS. The authors' suggestion of timers is easy to implement. Other methods may include empowering the code timer to stop the POCUS after a predetermined amount of time and limiting the number of POCUS exams performed throughout the cardiac arrest to one near the beginning and others when there would reasonably be determined to change management. Transesophageal echocardiogram requires no CPR pauses and therefore may make this discussion moot when it becomes readily available in all EDs.