Clinical physiology (Oxford, England)
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In a prospective study, heart rate and mean arterial pressure were related to estimated blood loss in 34 consecutive patients aged 23-92 years during resuscitation from haemorrhagic shock. Eighteen patients with a blood loss of less than 31 (1.9 [0.9-3.0] l) (median and range), corresponding to 34 (16-46) % of estimated blood volume, had a heart rate of 83 (60-160) beats min-1 and a mean arterial pressure of 62 (35-73) mmHg. ⋯ It is concluded that reversible hypovolaemic shock is associated with a relatively low heart rate (approximately 80 beats min-1) and that tachycardia (approximately 120 beats min-1) is associated with profound bleeding. Hypovolaemic shock with tachycardia may represent a transition to an irreversible stage.