Ultrasound use during cardiopulmonary resuscitation is associated with delays in chest compressions

Does use of point-of-care ultrasound (POCUS) in cardiopulmonary resuscitation lengthen the duration of pulse checks beyond the guideline recommendation of 10 seconds?

• Design
  • Prospective cohort study
• Population
  • This was a single center study performed at an adult, urban, tertiary care, academic medical center
  • All patients, 18 years of age or older, who presented to the emergency department (ED) in cardiac arrest or in whom cardiac arrest occurred while in the ED were eligible for enrollment
• Exclusion criteria 
  • No documentation of a pulse check
  • Not placed in one of three designated resuscitation rooms with continuous video monitoring capability
  • Video monitoring obtained was not available or image quality was too poor for extraction of data
• Intervention
  • All cardiac arrest resuscitations were recorded by video camera
    • Researchers recorded the duration of pulse checks (in milliseconds) and whether POCUS was used
• Outcomes
  • Duration of pulse checks with the use of POCUS

• • 23 patients enrolled
  • 123 individual rhythm checks
  • The use of POCUS significantly increased the pulse-check duration by 8.4 seconds (95% CI, 6.7-10.0 [p<0.0001])
  • Age and BMI did not affect the duration of pulse checks or CPR interruptions
  • No findings on any of the POCUS images prompted a procedure
  • Survival to ED discharge/hospital admission: 35% (8/23)
  • Survival to hospital discharge: 4% (1/23)
  • Survival at 30 days: 4% (1/23)

• Strengths
  • Data collected directly from video which removes any bias on recall of events that occurred during cardiopulmonary resuscitation
• Limitations
  • Small number of patients included in the study
  • Single center study reduces its external validity
  • No information of level of training of US operators
  • No commentary on the impact of POCUS on mortality or neurologic outcomes

"The use of POCUS during cardiac arrest resuscitation was associated with an increase in the duration of pulse checks by 8.4 seconds, causing interruptions in high-quality chest compressions nearly double the 10-second duration recommended by current international cardiopulmonary resuscitation guidelines. It is critical for acute care providers to pay close attention to the duration of CPR interruptions when using POCUS during cardiac arrest resuscitation."

With the introduction of novel indications for POCUS, we need to be aware of both the benefits and harms. This is an important study that identifies a potential harm of POCUS during CPR. There is no doubt from this data that POCUS did result in prolonged pulse checks above the guideline recommended 10 seconds. While this study does not directly tell us that POCUS increases mortality in cardiac arrest (as it is much too small), there is clear evidence that increased interruptions in chest compressions during CPR leads to worse outcomes.

The utility of this study is that it identifies a problem with POCUS in which there are clear solutions. With this new evidence, we must take a thoughtful approach to use of POCUS during CPR. Some proposed solutions to address this problem include:

• • Identifying personnel during CPR who can verbalize the time spent during pulse check to make providers acutely aware of when CPR should be resumed ("10, 9, 8, 7...")
  • Recording a POCUS clip for 5 seconds, then reviewing the stored images while CPR is resumed
  • Having a care provider ready to perform POCUS exam with probe on chest just before chest compressions are withheld
  • Use of transesophageal (TEE) POCUS which allows for image acquisition during ongoing CPR

The findings of this paper are definitely not the end of POCUS in CPR, as I find that there are numerous reasons that it is useful (i.e. monitoring of proper chest compression location, identification of reversible etiology of cardiac arrest, prognostication, closure for health care providers during end of resuscitations...), however I would like to see larger studies on this topic as well as quality improvement and awareness of this potential harm of prolonged pulse checks secondary to POCUS utilization.

This post was written by Michael Macias, MD, Ultrasound Fellow at UCSD.

1. 1. Gaspari R, e. (2017). Emergency department point-of-care ultrasound in out-of-hospital and in-ED cardiac arrest. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 8 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/27693280

   2. Link MS et al. Part 7: Adult Advanced Cardiovascular Life Support: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2015 Nov 3;132(18 Suppl 2):S444-64.

   3. Huis In 't Veld MA, e. (2017). Ultrasound use during cardiopulmonary resuscitation is associated with delays in chest compressions. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 8 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/28754527