Research Article

Vagal slowing of the heart during haemorrhage: observations from 20 consecutive hypotensive patients.

Br Med J (Clin Res Ed) 1986; 292 doi: http://dx.doi.org/10.1136/bmj.292.6517.364 (Published 08 February 1986) Cite this as: Br Med J (Clin Res Ed) 1986;292:364
  1. K Sander-Jensen,
  2. N H Secher,
  3. P Bie,
  4. J Warberg,
  5. T W Schwartz

    Abstract

    Heart rate and arterial blood pressure were monitored in 20 consecutive patients during resuscitation from haemorrhagic shock. The mean blood loss (2.3 (SEM 0.3) 1) corresponded to 36(4)% of their estimated mean blood volume. During shock the mean blood pressure was 81/55 (3/2) mm Hg and heart rate 73 (3) beats/min. Administration of blood and crystalloids resulted in immediate increases to 111/72 (2/2) mm Hg and 102 (3) beats/min followed by steady state values of 131/79 (6/3) mm Hg and 82 (2) beats/min. In three otherwise healthy patients plasma concentrations of the vagally regulated hormone pancreatic polypeptide rose from resting values of 64-77 pmol/l (272-327 pg/ml) to 198-280 pmol/l (842-1190 pg/ml). These findings suggest that reversible hypotensive hypovolaemic shock is characterised by a decrease in heart rate conceivably reflecting an increase in vagal tone.