title: Metabolic and hormonal responses to induced hypotension for middle ear surgery.
abstract: We have investigated in 30 patients the metabolic and hormonal responses to middle ear surgery using induced hypotension to a mean arterial pressure of 55 mm Hg. A standardized anaesthetic technique of propranolol, thiopentone-vecuronium-isoflurane was used in all patients and hypotension induced with sodium nitroprusside, trimetaphan camsylate or additional isoflurane. All patients showed a classic stress response with an increase in circulating blood glucose, cortisol and growth hormone concentrations. Blood lactate and plasma uric acid concentrations changed little during operation, suggesting that tissue oxygenation was adequate. However, the former declined after operation, possibly as a result of the concomitant use of propranolol. There were no significant differences between the three hypotensive techniques in their effects on the hormonal and metabolic response, although the increase in blood glucose concentration in the trimetaphan group was obtunded. We conclude that induced hypotension for middle ear surgery induced an endocrine and metabolic response of small magnitude and short duration.
authors.affiliation: Department of Anaesthesia, Royal National Throat, Nose and Ear Hospital, London.
authors.forename: M C
authors.initials: MC
authors.lastname: Newton
authors.forename: G D
authors.initials: GD
authors.lastname: Chadd
authors.forename: B
authors.initials: B
authors.lastname: O'Donoghue
authors.forename: S M
authors.initials: SM
authors.lastname: Sapsed-Byrne
authors.forename: G M
authors.initials: GM
authors.lastname: Hall
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D004432:Ear, Middle / Q000601:surgery*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006728:Hormones / Q000097:blood*; D006801:Humans; D007023:Hypotension, Controlled; D007530:Isoflurane / Q000494:pharmacology; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D008875:Middle Aged; D009599:Nitroprusside / Q000494:pharmacology; D011773:Pyruvates / Q000097:blood; D019289:Pyruvic Acid; D014294:Trimethaphan / Q000494:pharmacology; D014527:Uric Acid / Q000097:blood; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D006728:Hormones; D007773:Lactates; D011773:Pyruvates; D014665:Vasodilator Agents; D009599:Nitroprusside; D014527:Uric Acid; D019344:Lactic Acid; D014294:Trimethaphan; D019289:Pyruvic Acid; C017774:trimethaphan camsylate; D007530:Isoflurane