Isoflurane Adrenaline

Enflurane produces a dose-related decrease in systemic arterial blood pressure secondary to reductions in cardiac output and systemic vascular resistance. There is evidence that cardiac output is partially maintained by a compensatory increase in heart rate. This effect seems dependent on a degree of hypercardia and does not occur during controlled ventilation. Enflurane and halothane depress myocardial contractility to a similar extent and less than isoflurane. Enflurane does not sensitise the heart to the effects of catecholamines to any significant extent and adrenaline (epinephrine) may be given subcutaneously for control of bleeding. 

A 65-year-old man undergoing elective sternal debridement and rewiring was given a prophylactic infusion of vancomycin 1 g preoperatively. Anesthesia was induced with thiopental, suxamethonium, and fentanyl, and maintained with fentanyl, vecuronium, and isoflurane. A few minutes after wound irrigation with bacitracin (about 25U/ml), his blood pressure fell precipitously, necessitating intravenous fluids and adrenaline. His face and arms were flushed. Afterwards, he reported having had a rash several years before after the use of an over-the-counter ointment composed of polymyxin B, bacitracin, and neomycin. 

Sevoflurane has a similar effect on regional blood flow to other halogenated anesthetics, although it is perhaps slightly less of a coronary artery vasodilator than isoflurane. It reduces myocardial contractility and does not potentiate adrenaline-induced cardiac dysrhythmias (5). 

Isoflurane ha.s similar actions to halothane but is less cardiodepre.s-sant and doe.s not sensitize the heart to epinephrine (adrenaline). It causes dose-related hypotension by decreasing systemic vascular resistance. Only 0.2%i of the absorbed dose is metabolized and so isoflurane Ls very unlikely to cause hepatotoxiciiy,... 

Patients anaesthetised with inhalational anaesthetics (particularly cyclopropane and halothane, and to a lesser extent desflurane, enflurane, ether, isoflurane, methoxyflurane, and sevoflurane) can develop cardiac arrhythmias if they are given adrenaline (epinephrine) or noradrenaline (norepinephrine), unless the dosages are very low. Children appear to be less susceptible to this interaction. file addition of adrenaline to intrathecal tetracaine enhances the sedative effects of propofol. 

A 22-year-old woman in good health was anaesthetised for surgery with nitrous oxide/oxygen and isoflurane. Twenty minutes after induction she was given an injeetion of 0.2 units of vasopressin into the eervix. Within seeonds she developed severe hypotension and bradycardia, and over the next 30 minutes blood pressures as low as 70/35 mmHg and heart rates as low as 38 bpm were recorded. She was treated with atropine and adrenaline (epinephrine), and eventually made a full recovery. This patient was wearing a transdermal nicotine patch. ... 

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