Welcome to “Next Gen Shorts”, where we look to take a recent study focused on military and prehospital medicine, and condense it into a quick manageable read to ensure you get what’s most important for your practice.

Today’s paper is on the utility of radial pulse palpation for estimating systolic blood pressure.

The Background:

Blood pressure (BP) assessment is an essential part of initial vital signs (VS) measurement, as well as overall evaluation of most patients, especially trauma.  Additionally, it is taught as part of foundational training for medical providers of all levels, including medics.  BP is generally measured using a sphygmomanometer, better known as a “blood pressure cuff”, or “BP cuff”.  Historically, numerous courses, to include prior iterations of Advanced Trauma Life Saver (ATLS) and military instruction endorsed approximating a patient’s systolic blood pressure (SBP) using a palpable pulse at one of 3 sites to effectively estimate what could be obtained with a BP cuff.1-3  Despite its widespread use in both civilian and military medical practice, only a few studies have evaluated utilization of palpable pulse to estimate SBP, with poor results for its use.2,3  Perhaps in part due to these findings and other criticism, ATLS notably removed the inclusion of palpable pulse to estimate SBP from its latest teachings.1

However, anyone who has discussed combat trauma assessments has likely heard of this dogma, and knows someone who advocates for it.  But little to no research has sought to evaluate the use of pulse palpation in the combat setting.

The Paper:

Naylor JF, Fisher AD, April MD, Schauer SG. An analysis of radial pulse strength to record blood pressure in the Department of Defense Trauma Registry.  Mil Med. 2020 Aug 5:usaa197.  PMID: 32754740.

The Question:

Is radial pulse strength palpation correlated with SBP in the battlefield setting?

What the Researchers Did:

  • A retrospective search of the Department of Defense Trauma Registry (DoDTR) records from January 2007 to August 2016
  • Included all casualties with at least 1 documented SBP reading and a recorded corresponding pulse quality
  • If casualties had more than 1 documented unique SBP with a recorded corresponding pulse quality, all paired recordings were included for analysis
  • Subjects were stratified to SBP > 80 mmHg and < 80 mmHg

Demographic Results:

  • 38,769 encounters in the DODTR; 28,222 included for review based on diagnosis criteria
  • 22,192 had at least 1 radial pulse strength documented with a corresponding SBP
  • 27,366 total SBP measurements were documented in the DoDTR during this time
  • Most (55.8%) were injured by explosive
  • Median injury severity score (ISS) = 9

Research Question Results:

In patients with a documented SBP < 80 mmHg:

  • 55.6% of patients had documented strong radial pulse
    • 29.3% of patients had a documented weak radial pulse
    • 15.1% of patients had a documented absent radial pulse

These findings were statistically significant (p < 0.001)

Conclusion:

Characterization of the radial pulse using the historical binary measurement of > or < 80 mmHg is NOT a reliable indicator of hypotension.

Medic Bottom Line:
Prior civilian-based studies have demonstrated that the palpable pulse method is unreliable, and accuracy worsens with decreasing SBP.  This unique battlefield-based study corroborates these findings to at the very least warn medical providers at all levels not to rely solely upon palpation as a substitution for device measurement.  In the end, bring your BP cuff.

References:

  1. Deakin CD et al. Accuracy of the Advanced Trauma Life Support Guidelines for Predicting Systolic Blood Pressure Using Carotid, Femoral, and radial Pulses: Observational Study. BMJ 2000
  2. Poulton TJ et al. ATLS Paradigm Fails. Ann Emerg Med 1988.
  3. Salim Rezaie, “Is Advanced Trauma Life Support (ATLS) Wrong About Palpable Blood Pressure Estimates?”, REBEL EM blog, November 1, 2013. Available at: https://rebelem.com/atls-wrong-palpable-blood-pressure-estimates/.