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Three Part Question

In [the adult trauma patient] is [the presence of a radial pulse] an [indicator of a blood pressure of at least 80mmHg]?

Clinical Scenario

You heard from a colleague that "if there is a radial pulse, then the SBP is at least 80mmHg", you wonder if this is actually true in the trauma patient.

Search Strategy

PubMed http://www.ncbi.nlm.nih.gov

((radial[All Fields] AND ("pulse"[MeSH Terms] OR "pulse"[All Fields] OR "heart rate"[MeSH Terms] OR ("heart"[All Fields] AND "rate"[All Fields]) OR "heart rate"[All Fields])) AND ("injuries"[Subheading] OR "injuries"[All Fields] OR "trauma"[All Fields] OR "wounds and injuries"[MeSH Terms] OR ("wounds"[All Fields] AND "injuries"[All Fields]) OR "wounds and injuries"[All Fields])) AND ("blood pressure"[MeSH Terms] OR ("blood"[All Fields] AND "pressure"[All Fields]) OR "blood pressure"[All Fields] OR "blood pressure determination"[MeSH Terms] OR ("blood"[All Fields] AND "pressure"[All Fields] AND "determination"[All Fields]) OR "blood pressure determination"[All Fields] OR ("blood"[All Fields] AND "pressure"[All Fields]) OR "blood pressure"[All Fields] OR "arterial pressure"[MeSH Terms] OR ("arterial"[All Fields] AND "pressure"[All Fields]) OR "arterial pressure"[All Fields] OR ("blood"[All Fields] AND "pressure"[All Fields]))

Search Outcome

This search returned 29 results of which only two were relevant

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
McManus et al October - December 2005 United states	18 to 50 year old trauma patients. 342 sets of patient data analysed, medical records that did not describe pulse characters were not considered.	Retrospective study and data review.	difference in SBP	The SBP taken at the scene was a mean of 26 mm Hg lower in those patients with weak radial pulse characters (102 mm Hg versus 128 mm Hg). Similarly, the lowest mean SBPs recorded in the field between the normal- and weak-pulse-character groups were 112 mm Hg and 99 mm Hg, respectively.	No mention of other influences of radial pulse character such as blood loss, injuries or environmental. No description of blood pressure monitoring equipment (cuff sizes, manual or automatic etc).
			difference in mortality	Patient mortality increased with weak pulse character such that the mortality rates were 3% for the normal-pulse-character group and 29% for the weak-pulse-character-group (odds ratio = 15.2).
Deakin & Low September 2000 United Kingdom	20 adults between 18 - 79 who had hypotension secondary to hypovolaemic shock and in whom invasive arterial blood pressure monitoring had been established.	Clinical data collection and statistical analysis	Group 1 all pulses present	10/12 (83%) subjects had a systolic blood pressure <80 mm Hg (mean 72.5 mm Hg (reference range 55.3-89.7 mm Hg)).	Patients included in study where in the operating theatre. There was no mention of anaesthetic drugs that could influence radial pulse pressure. Very small study, not all pulses were palpable due to sterile drapes.
			Group 2 femoral and carotid pulses present only	10/12 (83%) subjects had a systolic blood pressure <70 mm Hg (mean 66.4 mm Hg (50.9-81.9 mm Hg)
			Group 3 carotid pulse only	none of the four patients had a systolic blood pressure >60 mm Hg as predicted by the advanced trauma life support guidelines.
			Group 4 radial, femoral and carotid pulses absent	2/3 patients had a systolic blood pressure <60 mm Hg

Comment(s)

Deakin & Low indicate that the estimation of blood pressure by palpitation is unreliable. Whereas McManus et al demonstrated that the lowest mean SBP for a palpable but weak radial pulse was 99 mmHg indicating possible hypoperfusion

Clinical Bottom Line

Many guidelines and consensus papers suggest that fluid therapy should be guided to the PRESENCE of a radial pulse which is used as an indicator of flow as opposed to a specific SBP. Relying on a radial pulse to indicate a specific blood pressure is unreliable and should not guide treatment (i.e SBP >110 mmHg in head injuries) but it may be a useful indicator of fluid responsiveness.

References

1. McManus J, Yershov AL, Ludwig D, Holcomb JB, Salinas J, Dubick MA, Convertino VA, Hinds D, David W, Radial pulse character relationships to systolic blood pressure and trauma outcomes.
2. Charles D Deakin, J Lorraine Low, Accuracy of the advanced trauma life support guidelines for predicting systolic blood pressure using carotid, femoral, and radial pulses: observational study BMJ 673–674 september 2000