Haemodynamic responses to induced arterial hypotension in children.

Cardiovascular measurements were made in 12 children in whom arterial hypotension was induced with pentolinium and halothane. Propranolol was given to five patients who exhibited tachycardia. Measurements were made at the following stages: before induction of hypotension, 5 min after the administration of pentolinium, when a "dry" opening field was obtained, at the time of maximum hypotension and when arterial pressure had returned to 90% of the control values. The decrease in arterial pressure 5 min after the administration of pentolinium was accompanied by tachycardia, but there was no significant change in cardiac index and the operative field was congested. A substantial decrease in cardiac output occurred when a "dry" field was obtained.