- 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?
“ATLS Paradigm Fails” 
- 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” 
What they did: In 20 pts with hypovolemic shock and arterial lines, pulses were palpated by an observer blinded to BP readings.
- 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.
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
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