Haemodynamic Responses to Enflurane Anaesthesia and Hypovolaemia in the Dog, and Their Modification by Propranolol

Horan, Brian; Prys‐Roberts, C.; Roberts, John G.; Bennett, Malcolm J.; Foëx, P.

doi:10.1093/bja/49.12.1189

Cited by 70 publications

(17 citation statements)

References 18 publications

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“…One may encounter a limited reduction in LV function and mean arterial blood pressure, but negligible change in heart rate or cardiac output. 10 Indeed, the introduction of esmolol, with its rapid onset and truncated half-life, offered anesthesiologists a valuable adjuvant therapy to treat intraoperative hypertension, tachycardia, and myocardial ischemia. Esmolol given immediately before the induction of anesthesia and laryngoscopy has proven efficacious in blunting untoward hemodynamic responses to endotracheal intubation.…”

Section: Beta Blockersmentioning

confidence: 99%

Cardiovascular Pharmacotherapeutic Considerations in Patients Undergoing Anesthesia

Wolf

McGoldrick

2011

Cardiology in Review

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Demographic shifts toward an increasingly older population have resulted in a high prevalence of persons taking cardiovascular medication. Many patients on cardiovascular medications will require surgical intervention for conditions often unrelated to their cardiovascular pathology. Cardiologists and anesthesiologists alike must be knowledgeable about the potential interactions between cardiovascular drugs and anesthetics agents or adjuvant therapies administered perioperatively. Current recommendations suggest that beta blockers, calcium channel blockers, amiodarone, and alpha2 agonists should be continued throughout the perioperative period, whereas angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and diuretics should be discontinued on the morning of surgery and resumed in the immediate postoperative period, unless contraindicated.

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Section: Beta Blockersmentioning

confidence: 99%

Cardiovascular Pharmacotherapeutic Considerations in Patients Undergoing Anesthesia

Wolf

McGoldrick

2011

Cardiology in Review

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“…Another assumption may be that the enhancement of PRA results partly from the renal sympathetic stimulation and the centrally released catecholamines, as supported by other studies (25,26). Even though several groups of investigators (3, [27][28][29][30] have assessed the effects of isoflurane on autonomic function, comparison of the various results is difficult due to differences in experimental protocols such as duration of procedure, dosing regimen, presence or severity of cardiovascular disease, and the methods used to assess autonomic function. One should point out with determination that the nature and the potency of narcotic analgesia as well as the magnitude of the stress response is frequently unfocused.…”

Section: 1-03 Mg/kg Of Phenoperidine During Isoflurane-in-mentioning

confidence: 99%

Impact of surgical stress on the haemodynamic profile of isoflurane–induced hypotension

Bernard¹,

Pinaud²,

Macquin‐Mavier³

et al. 1988

Acta Anaesthesiol Scand

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It has been suggested that stimulation of adrenoreceptors could be responsible for some of the haemodynamic effects of isoflurane. But there are no solid data demonstrating the role of sympatho-adrenal stimulation induced by pain during isoflurane administration. The impact of surgical stress on the haemodynamic profile of isoflurane-induced hypotension has been investigated in 28 patients (47-76 years), scheduled for total hip arthroplasty. After premedication with morphine hydrochloride (0.1 mg/kg), patients were randomly assigned to receive either no fentanyl (control group) or fentanyl (5 micrograms/kg before tracheal intubation, 5 micrograms/kg before skin incision, and 2 micrograms/kg each 15 min during the 1st hour). Isoflurane was given to maintain mean arterial blood pressure in the range 6.7-8 kPa in both groups. Haemodynamic data and blood samples for determination of plasma renin activity (PRA) and epinephrine (E) and norepinephrine (NE) levels were collected before and during hypotension. The fentanyl group and the control group differed significantly during hypotension: heart rate, cardiac index, oxygen consumption and E, NE and PRA were lower (P less than 0.01) in the fentanyl group than in control group. Fentanyl lowered the required concentration of isoflurane to achieve the same degree of hypotension (end-tidal concentration: 0.8 +/- 0.2% in the fentanyl group and 1.4 +/- 0.15% in the control group; P less than 0.001). Our results demonstrate that the cardiovascular effects of higher isoflurane concentrations in the absence of narcotic analgesia are counterbalanced by adrenergic stress stimulation of released epinephrine and norepinephrine. Among the likely reasons for catecholamine release during isoflurane administration, inadequate analgesia may be considered.

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“…Catecholamine increases are well tolerated (Johnston et al 1976) allowing enflurane anaesthesia in patients with phaeochromocytoma. The haemodynamic effects of enflurane are marked following administration of propranolol in dogs, and a withdrawal of 20% of blood volume is poorly tolerated (Horan et al 1977).…”

Section: Circulationmentioning

confidence: 99%

Clinical Pharmacokinetics of the Inhalational Anaesthetics

Dale

Brown

1987

Clinical Pharmacokinetics

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At present, the most widely used inhalational anaesthetics are the halogenated, inflammable vapours halothane, enflurane, isoflurane and the gas nitrous oxide. The anaesthetic effect of these agents is related to their tension or partial pressure in the brain, represented at equilibrium by the alveolar concentration. The minimum alveolar concentration for a specific agent is remarkably constant between individuals. The uptake and distribution of inhalational anaesthetics depends on inhaled concentration, pulmonary ventilation, solubility in blood, cardiac output and tissue uptake. Inhalational anaesthetics are mainly eliminated by pulmonary exhalation, but significant amounts of halothane are removed by hepatic metabolism. Inhalational agents currently in use have acceptable pharmacokinetic characteristics, and clinical acceptance depends on their potential for adverse effects. Induction of anaesthesia with halothane is rapid and relatively pleasant and it is the agent of choice for paediatric anaesthesia. Between 20 and 50% is metabolised, and the parent drug is a potent inhibitor of drug metabolism. Post-operatively enzyme induction may follow. The major disadvantages of halothane are myocardial depression, propensity to evoke cardiac arrhythmias and the rare but serious halothane hepatitis. Induction and recovery from enflurane anaesthesia is rapid. Metabolism accounts for 5 to 9% of the elimination. The metabolic product inorganic fluoride may in rare cases cause renal toxicity. Enflurane is a weak inhibitor of drug metabolism at anaesthetic concentrations. Enflurane depresses circulation more than halothane by reducing both myocardial contractility and systemic vascular resistance, but cardiac rhythm is stable. Enflurane anaesthesia may, unlike the other agents, induce epileptic activity. Enflurane is widely used as replacement for halothane in adults. Despite its low blood-gas solubility, the airway irritability of isoflurane precludes a faster induction of anaesthesia than with halothane. Isoflurane is almost resistant to biodegradation. Myocardial contractility is maintained during isoflurane anaesthesia and cardiac rhythm is stable except for the occurrence of tachycardia in some patients. Isoflurane is the inhalational agent of choice for neurosurgical operations. Sevoflurane is an experimental ether vapour: induction and recovery is fast and pleasant. It is metabolised to the same extent as enflurane and subnephrotoxic concentrations of inorganic fluoride may result. Sevoflurane has fewer respiratory and cardiovascular depressant effects than halothane and may be a future alternative for paediatric anaesthesia.(ABSTRACT TRUNCATED AT 400 WORDS)

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Haemodynamic Responses to Enflurane Anaesthesia and Hypovolaemia in the Dog, and Their Modification by Propranolol

Cited by 70 publications

References 18 publications

Cardiovascular Pharmacotherapeutic Considerations in Patients Undergoing Anesthesia

Cardiovascular Pharmacotherapeutic Considerations in Patients Undergoing Anesthesia

Impact of surgical stress on the haemodynamic profile of isoflurane–induced hypotension

Clinical Pharmacokinetics of the Inhalational Anaesthetics

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