Author: Matt Olocco, MD; Emergency Medicine Resident Physician, WashU School of Medicine
Editors: Alex Blau, DO, EMS Physician Fellow – ChristianaCare / Delaware Division of Public Health; Michael DeFilippo, DO, Assistant Professor of EM & EMS, WashU School of Medicine
Editors’ Introduction:
Accurate and timely pulse detection during cardiac arrest is critical for both guiding resuscitation efforts and minimizing interruptions in chest compressions. Current ACLS protocols rely primarily on manual palpation, yet emerging evidence suggests this method is often inaccurate and time-consuming, potentially lowering chest compression fraction (CCF) and impacting outcomes. Point-of-care ultrasound (POCUS) has been shown to improve accuracy and reduce pulse check duration in the emergency department, and growing literature supports its feasibility and potential benefits in the prehospital setting. This review examines the existing evidence for ultrasound use in pulse detection, highlights its impact on CCF, and explores the implications for EMS practice.
Case:
You are alerted to respond to a home where a 62 year old male had a witnessed loss of consciousness and collapse. Family members who witnessed the fall and collapse noted that they did not feel a pulse and have started compressions. Per family, he has a known cardiac history with prior coronary stents and reportedly does not take any of his prescribed medications. When you arrive at the scene, compressions have been ongoing for 7 minutes but you notice that the family have been checking pulses every 15 seconds. After taking over compressions and hooking him up to the monitor, you notice he has organized bradycardic electrical activity though you are unable to feel a pulse. You resume compressions and start transportation to the nearest cardiac center. En route you continue through the ACLS algorithm and continue to appreciate PEA. However, when feeling for a pulse you are unsure if you are feeling bumps in the road, a pulse, or nothing at all and you start to notice you are taking more time with each pulse check to try and differentiate this. You wonder if there are any other strategies you can employ to improve your detection of a pulse and cut down on the timing of your compression pauses.
Literature Review:
CCF Importance in Cardiac Arrest Outcomes
Reducing ‘time off the chest’ has been highly stressed as a vital aspect in high quality cardiopulmonary resuscitation (CPR). The American Heart Association (AHA) has published guidelines demonstrating that a higher chest compression fraction (CCF), defined as the proportion of time that compressions are conducted in a cardiac arrest, is directly related to improved clinical outcomes (1). A prospective observational cohort study by Christenson et al. has demonstrated increased CCF is predictive of improved survival in prehospital ventricular fibrillation/tachycardia arrest (2). An additional prospective cohort study by Vaillancourt et al. highlighted that increased CCF is also associated with increased likelihood of return of spontaneous circulation (ROSC) in prehospital non-ventricular fibrillation arrest (3). Per the AHA, an attainable CCF goal is at least 80% (1).
Common Barriers to Maintaining High CCF
For anyone who has been involved in a cardiac arrest resuscitation, you know it can be very challenging to find areas of improvement to keep that fraction high. Areas where CCF can be hindered include during pulse checks, charging and shocks, transfers, applying compression devices, etc. Pulse checks is of particular interest among this list as it is not only a point of improvement for CCF but also for appropriate rhythm detection.
Manual Palpation Versus Ultrasound in the ED
Manual pulse detection has been the mainstay for ACLS, however, evidence over the last decade has been consistently demonstrating that ultrasound can be a superior tool in comparison. When looking into Emergency Department cardiac arrests, doppler ultrasound has been shown to be more accurate than manual palpation in detecting femoral artery pulse, confirmed by arterial line measurements. Femoral artery doppler ultrasound also had the added benefit of detecting a systolic blood pressure of greater than or equal to 60mmHg when peak systolic velocity is greater than 20 cm/s compared to manual palpation (4). What was more jarring was that the accuracy of manual palpation of any pulse was only 54% while detection with doppler ultrasound was 95.3% (4). Along with this, sensitivity for manual palpation versus doppler ultrasound was 40% and 93.5%, respectively, while specificity was similar >90%, indicating manual technique introduces higher likelihood of false negatives (4).
Ultrasound’s Impact on Pulse Check Duration
Data has also demonstrated that ultrasound can be beneficial for increasing the CCF. In a prospective study conducted by Kang et al, carotid pulse detection by ultrasound (via pulsatility and compressibility) had a median time of 1.62 seconds compared to manual palpation of 3.5 seconds. This study included 25 patients and 155 pulse checks of which no pulse check with ultrasound exceeded 10 seconds while five cases with manual palpation did (5).
Emerging Prehospital Applications
How does this apply to pre-hospital cardiac arrest care? Emerging data from AHA Circulation has shown promise in paramedic performed point of care ultrasound in out of hospital cardiac arrest (OHCA) care. In this retrospective analysis, carotid and subxiphoid ultrasound was used for pulse detection in medical OHCA patients. Ninety-four patients were included with a total of 196 ultrasound recordings. Of the pulse checks, 73% were less than 10 seconds. Carotid assessment was more likely than subxiphoid to be of adequate views and more likely to be less than 10 seconds in duration (6).
Feasibility of Training Paramedics in Ultrasound
The data to support paramedic use of point of care ultrasound with just several hours of training is also favorable. In a prospective cohort study, paramedics performed a 4 hour training session on ultrasound use in prehospital cardiac arrest care and demonstrated ability to obtain adequate scans. The paramedics obtained scans for 49 patients and of these scans, 85.7% were considered adequate views and 87.7% had accurate interpretations per an expert ultrasound investigator. Additionally, 94.7% of the compression pauses were less than 10 seconds. The paramedics reported that 14 of these cases (28.6%) had changes in treatment or transport decisions as a direct result of ultrasound findings (7).
Future Directions and Research Needs
Data for in-hospital use of ultrasound in cardiac arrest care is robust and the data for prehospital use is quickly developing though more investigation is needed. More evidence to favor feasibility to train paramedics in ultrasound and investigation into how this implementation could affect patient-centered outcomes such as survival, neurologic outcomes, or hospital length of stay would be pivotal in determining indication for widespread adoption.
References
- Meaney PA, Bobrow BJ, Mancini ME, et al. Cardiopulmonary resuscitation quality: metrics to reflect effectiveness. Circulation. 2013;128(1):S89–S97. doi:10.1161/CIR.0b013e31829d8654
- Christenson J, Andrusiek D, Everson‑Stewart S, et al. Chest compression fraction determines survival in patients with out‑of‑hospital ventricular fibrillation. Circulation. 2009;120(13):1241–1247. doi:10.1161/CIRCULATIONAHA.109.852202
- Vaillancourt C, Everson‑Stewart S, Christenson J, et al. The impact of increased chest compression fraction on return of spontaneous circulation for out‑of‑hospital cardiac arrest patients not in ventricular fibrillation. Resuscitation. 2011;82(12):1501–1507. doi:10.1016/j.resuscitation.2011.07.011
- Cohen J, Smith K, Thompson J, et al. Femoral artery Doppler ultrasound is more accurate than manual palpation for pulse detection in cardiac arrest. Resuscitation. 2022;S0300‑9572(22)00032‑6. doi:10.1016/j.resuscitation.2022.03.026
- Thompson J, Lee R, Patel A, et al. Point‑of‑care ultrasound compression of the carotid artery for pulse detection during cardiac arrest. Resuscitation. 2022;S0300‑9572(22)00590‑1. doi:10.1016/j.resuscitation.2022.05.901
- Panchal AR, Wells L, Crocker K, et al. View adequacy and compression delays during resuscitation: a point‑of‑care ultrasound assessment (Abstract Sa306). Circulation. 2024;150(Suppl_1):Sa306. doi:10.1161/CIRC.150.suppl_1.Sa306
- Marin J, Barchitta M, Scorpiniti M, et al. Point‑of‑care ultrasound use by EMS providers in out‑of‑hospital cardiac arrest. Prehosp Disaster Med. 2021;36(5):606–613. doi:10.1017/S1049023X21001023
