Is Advanced Trauma Life Support (ATLS) Wrong About Palpable Blood Pressure Estimates?

In Advanced Trauma Life Support (ATLS), we learned that a carotid, femoral, and radial pulse correlates to a certain systolic blood pressure (SBP) in hypotensive trauma patients.  Specifically ATLS stated:
  •  Carotid pulse only = SBP 60 – 70 mmHg
  •  Carotid & Femoral pulse only = SBP 70 – 80 mmHg
  •  Radial pulse present = SBP >80 mmHg

Is this true or a myth?  There were two studies that evaluated this paradigm.

“ATLS Paradigm Fails” [1]

 What they did: In 20 hypovolemic trauma patients with SBP
  •  5/20 (25%) pts were correctly predicted by ATLS guidelines
  • 10/20 (50%) pts had false overestimation of BP by ATLS guidelines
  •  False overestimation of BP was greatest in pts with lowest BPs
  • Mean difference of actual and estimated BP using ATLS was 34 mmHg

Conclusion:  Radial pulses are often present in severely hypotensive hypovolemic patients, meaning the ATLS paradigm is invalid.

“Accuracy of ATLS guidelines for predicting SBP” [2]

What they did: In 20 pts with hypovolemic shock and arterial lines, pulses were palpated by an observer blinded to BP readings.

What they found: The disappearance of pulse always occurred in the following order radial > femoral > carotid pulse. There were 4 subgroups:
  • Group 1: Radial, femoral, and carotid pulses present
    • 10/12 (83%) had SBP< 80 mm Hg
  • Group 2: Femoral and carotid pulses only
    • 10/12 (83%) had SBP < 70 mm Hg
  • Group 3: Carotid pulse only
    • 0/4 (0%) had SBP >60 mmHg
  • Group 4: Radial, femoral, and carotid pulses absent
    • 2/3 (67%) had SBP < 60 mm Hg

Conclusion: ATLS guidelines for assessing SBP are inaccurate and generally overestimate the patient’s SBP.

CLINICAL BOTTOM LINE:

Although very small studies, they were done by two different authors, using different methods (BP cuff vs arterial line).  Both came to the same conclusion: ATLS overestimates SBP based on palpation of radial, femoral, & carotid pulses. Another way to state this is, if using ATLS guidelines to guestimate BP, we are grossly underestimating the degree of hypovolemia our patients have.

UPDATE: These recommendations have now been removed from the 8th and 9th edition of ATLS

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. PMID: 10987771
  2. Poulton TJ et al. ATLS Paradigm Fails. Ann Emerg Med 1988. PMID: 3337405
Cite this article as: 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/.

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