Successful vasoconstrictor therapy of anaphylactoid reactions during induction of anaesthesia. A report of two cases.

Anaphylactoid reactions were evoked during intravenous induction of anaesthesia in two patients on three occasions. In the first patient the reaction occurred during the first anaesthetic on propranolol and hydrochlorthiazide medication due to hypertension. Since the major target organ for the anaphylactoid reaction in this patient was the pulmonary circulation, the cardiovascular collapse at his first anaesthetic was misinterpreted as a nonspecific reaction to anaesthesia reinforced by the beta-receptor blocking therapy. At the second anaesthetic central haemodynamics, plasma adrenaline (A) and noradrenaline (NA) were measured. Following injection of thiopentone sudden decreases of mean arterial blood pressure (60%), cardiac output (60%), and systemic vascular resistance (20%) were observed. Thirty minutes later, still during circulatory shock, the concentration of A had increased whereas that of NA was normal. In the second patient the anaphylactogenic drug was supposed to be thiopentone, suxamethonium or alcuronium. In this patient, the fall in arterial blood pressure was associated with bronchospasm and the sudden appearance of peripheral oedema. In both cases initial resuscitation comprised volume replacement and beta 1-agonist therapy but the cardiovascular state was not normalized until vasoconstricting agents were infused.