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.

Remifentanil and controlled hypotension; comparison with nitroprusside or esmolol during tympanoplasty

“…Controlled hypotension with either remifentanil, or esmolol, or nitroprusside ensured "good operative conditions". The hemodynamic data for nitroprusside and esmolol are in agreement with those previously reported in middle ear surgery 3,5,7 and in other surgery. 11,[20][21][22] Advantages and disadvantages of sodium nitroprusside for deliberate hypotension which include potency and short duration of action, and reflex tachycardia, tachyphylaxis, rebound hypertension, potential for cyanide toxicity, have been discussed several previous studies.…”

“…Lack of relationships between hypotension, heart rate and middle ear blood flow observed in the present study and in a previous one 4 could be explained by autoregulation, 2 8 altered baroreceptor activation, 3 0 enhanced sympathetic nerve activity 6 and/or renin angiotensin secretion. 5 Reduction of heart rate and hypotension with remifentanil and esmolol could account for the impairment of baroreflex regulatory mechanisms caused by propofol.…”

“…Since then, various drugs have been used to facilitate the induction of controlled hypotension for middle ear surgery including vasodilators such as sodium nitroprusside, [3][4][5][6] nicardipine, 4 nitroglycerin, 4 beta-adrenergic antagonists such as propranolol, 5 esmolol, 7 alpha and beta-adrenergic antagonist such as labetalol, 8 and high doses of potent inhaled anesthetics such as halothane. 3,5 Some disadvantages have been reported for these techniques including long postanesthetic recovery for halothane, 3 resistance to vasodilators, 4 tachyphylaxis 9 and cyanide toxicity 1 0 for nitroprusside, or possibility of myocardial depression for esmolol. 11 Remifentanil hydrochloride, a new ultra-short-acting µ-opioid receptor agonist, is now currently used in propofol total intravenous anesthesia (propofol-TIVA).…”

Anaesthetic Concerns in Functional Endoscopic Sinus Surgery

“…19,20 Tranexamic acid also has been used topically for control of bleeding in FESS. 23 Ethamsylate is haemostatic drug used for control of dysfunctional uterine bleeding 8,9 and periventricular haemorrhage in children. 24 Oral route has been used to control bleeding in dacryocystorhinostomy surgery and for control of epistaxis.…”

“…23,25 Gelatin thrombin matrix: It stops bleeding on an average of 2 minutes. 26 Some studies reported its adverse effect, 27,28,29 but one study evaluated its efficiency without complications.…”