The Pre-brief
Not to be too obvious, but one of the most important aspects of running a cardiac arrest is to determine if your patient has obtained a return of spontaneous circulation (ROSC). The palpation of pulses over the femoral or carotid artery has been a mainstay for decades. However, this method has proven to be inaccurate and should go the way of the rotary phone.
There are several viable methods of determining if your patient has a pulse:
- The Palpation Method: This is the method that most clinicians are familiar with. The rescuer would place their index and middle finger over the carotid or femoral artery during a pause in Cardiopulmonary Resuscitation (CPR) to see if they could palpate a pulse. While this method may be easy if your patient has great blood pressure, little soft tissue over the vessels, and you are truly placing your finger over the blood vessel, even then it is still highly inaccurate. Studies have shown how seasoned health care professionals take a significant time to identify a pulse during a pause in CPR and even then, they may not feel a pulse when there is cardiac activity.1,2
- Point-of-care Ultrasound (POCUS) Pulse Check: This is a newer concept in the past few years that replaces the rescuer’s fingers with an ultrasound probe. Essentially, the linear probe is placed over the groin or neck before the pause in compressions to identify the femoral or carotid arteries. Once located, CPR can be briefly paused (<5 sec), and you can look for pulsatile movement. The advantage is greater accuracy in identification of the vessels rather than guessing the location of the vessels with palpation. The pulsatile motion of the artery during a pause in CPR can be visualized rather than relying on the tactile sense of your fingers.3 This is an amazingly fast and efficient way of identifying a pulse but still has limitations of not being able to see cardiac activity that may not generate a significant pulse wave.
- Transthoracic echocardiogram (TTE): This method of identifying ROSC is highly specific/sensitive. Essentially, if you see cardiac activity and it’s organized, then you have ROSC. However, the patient may still be in cardiogenic shock and not have a distal pulse. Many rescuers use the subcostal approach to obtain the cardiac view. This method requires a brief <5-10 sec pause in compressions to capture the view. So as not to delay the resumption of CPR, take a video clip for examination during the next code cycle. If a subcostal view is difficult to obtain, a long parasternal look can be achieved instead – this can sometimes be a more challenging view to get quickly and should not delay the resumption of CPR.4
- Transesophageal echocardiogram (TEE): a newer player to resuscitation. While it is not commonly available, it is starting to make an appearance in some EDs and ICUs for arrest management. This modality is amazingly fast to apply and can be placed while compressions are in progress. It gives a great view of the heart with little technical difficulty (usually). Mainly, the TEE probe is placed in the esophagus in an intubated patient. The probe cannot be used with bag valve mask ventilation and is not ideal with supraglottic airways. Once in the esophagus, the probe is advanced until the heart is visualized. A mid esophageal 4-chamber or mid esophageal long-axis view is obtained. This can provide an enormous amount of information, including appropriate depth of compressions, correct hand placement for compressions (over the left ventricular outflow tract), and of course, cardiac activity. Additionally, TEE allows for assessment of potential causes of arrest/shock such as left ventricular failure, right ventricular failure, pulmonary embolism, pericardial tamponade, and hypovolemia. Chest compressions do not need to be paused to obtain views, and the probe can be left in place throughout the resuscitation as it does not obstruct access to the chest for compressions.5,6The challenge with TEE is the availability of the probes and credentialing/training of providers.
- Arterial line: Arterial lines are fantastic for cardiac arrest. They provide many of the essential physiologic components of resuscitation: quality of compressions, diastolic blood pressure, and once we have ROSC, it can help guide hemodynamic support. The challenge with arterial lines is the time and technical aspects of placing a line during CPR. In experienced hands, with good resource availability, arterial lines are invaluable and should be utilized whenever possible.
- End Tidal CO2 Monitoring (ETCO2): ETCO2 is probably the most practical adjunct for resuscitation, as it is typically available in most EDs and ICUs and is less invasive than an arterial line. This modality is best used with intubated patients but is also possible with supraglottic airways. Once an airway is placed, an ETCO2 waveform (not colorimetric) detector is applied to the advanced airway to allow continuous sampling of expired air. Chest compression effectiveness is confirmed by an appropriate capnographic waveform with ETCO2 values between 10–20 mmHg or higher, corresponding to the artificial circulation generated by closed chest compressions. ETCO2 values < 10 mm Hg indicate suboptimal compression quality and correlate with poor outcomes and mortality. EtCO2 <10 – 15mmHg at 20 minutes predicted a 0.8% chance of survival.7 A sudden rise in ETCO2 can correspond to ROSC and should prompt the team to assess this.
The Debrief
- Palpation: should go the way of the rotary phone
- ETCO2: most practical with few limitations
- POCUS Pulse Check: Newcomer on the block with some limitations
- TTE: Gold standard but has limitations
- TEE: Awesome when used appropriately and available
- Arterial line: Great if you have the time
References
Ochoa FJ, Ramalle-Gómara E, Carpintero JM, García A, Saralegui I. Competence of health professionals to check the carotid pulse. Resuscitation. 1998;37(3):173-175. doi:10.1016/s0300-9572(98)00055-0. PMID: 9715777.
Zengin S, Gümüşboğa H, Sabak M, Eren ŞH, Altunbas G, Al B. Comparison of manual pulse palpation, cardiac ultrasonography and Doppler ultrasonography to check the pulse in cardiopulmonary arrest patients. Resuscitation. 2018;133:59-64. doi:10.1016/j.resuscitation.2018.09.018. PMID: 30253230.
Simard RD, Unger AG, Betz M, Wu A, Chenkin J. The POCUS Pulse Check: A Case Series on a Novel Method for Determining the Presence of a Pulse Using Point-of-Care Ultrasound. J Emerg Med. 2019;56(6):674-679. doi:10.1016/j.jemermed.2019.02.013. PMID: 31003817.
- Hussein L, Rehman MA, Sajid R, Annajjar F, Al-Janabi T. Bedside ultrasound in cardiac standstill: a clinical review. Ultrasound J. 2019;11(1):35. Published 2019 Dec 30. doi:10.1186/s13089-019-0150-7. PMID: 31889224.
van der Wouw PA, Koster RW, Delemarre BJ, de Vos R, Lampe-Schoenmaeckers AJ, Lie KI. Diagnostic accuracy of transesophageal echocardiography during cardiopulmonary resuscitation. J Am Coll Cardiol. 1997;30(3):780-783. doi:10.1016/s0735-1097(97)00218-0. PMID: 9283540.
- Ahrens T, Schallom L, Bettorf K, et al. End-tidal carbon dioxide measurements as a prognostic indicator of outcome in cardiac arrest. Am J Crit Care. 2001;10(6):391-398. PMID: 11688606.
