Does tachycardia correlate with hypotension after trauma?
BACKGROUND
Tachycardia is believed to be closely associated with hypotension and is often listed as an important sign in the initial diagnosis of hemorrhagic shock, but the correlation between heart rate and hypotension remains unproved.


METHODS
Data were collected from all trauma patients, 16 to 49 years old, presenting to our university-based trauma center between July 1988 and January 1997. Moribund patients with a systolic blood pressure < or =50 or heart rate < or = 40 and patients with significant head or spinal cord injuries were excluded. Tachycardia was defined as a heart rate >or= 90 and hypotension as a systolic blood pressure < 90.


RESULTS
Hypotension was present in 489 of the 14,325 admitted patients that met the entry criteria. Of the hypotensive patients, 35% (169) were not tachycardic. Tachycardia was present in 39% of patients with systolic blood pressure 120 mmHg. Hypotensive patients with tachycardia had a higher mortality (15%) compared with hypotensive patients who were not tachycardic (2%, P = 0.003). Logistic regression analysis revealed tachycardia to be independently associated with hypotension (p = 0.0004), but receiver operating curve analysis demonstrated that the sensitivity and specificity of heart rate for predicting hypotension is poor.


CONCLUSIONS
Tachycardia is not a reliable sign of hypotension after trauma. Although tachycardia was independently associated with hypotension, its sensitivity and specificity limit its usefulness in the initial evaluation of trauma victims. Absence of tachycardia should not reassure the clinician about the absence of significant blood loss after trauma. Patients who are both hypotensive and tachycardic have an associated increased mortality and warrant careful evaluation.
Department of Surgery, University of California, San Francisco-East Bay, Oakland, California 94602, USA.
Gregory P
GP
Victorino
Felix D
FD
Battistella
David H
DH
Wisner
D000328:Adult; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007022:Hypotension / Q000150:complications*; D016015:Logistic Models; D008297:Male; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013610:Tachycardia / Q000150:complications*; D015599:Trauma Severity Indices; D014947:Wounds and Injuries / Q000150:complications*