The Cardiovascular Responses to the Addition of Nitrous Oxide to Fluroxene in Man

Smith, N. Ty; Eger, Edmond I.; Cullen, Bruce F.; Sawyer, Donald C.; Gregory, George

doi:10.1093/bja/44.2.142

Cited by 6 publications

(2 citation statements)

References 4 publications

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“…Nitrous oxide in oxygen has been found by other authors to have a myocardial depressive action, either when used as the sole anaesthetic agent (23,24) or when administered as an adjunct to intravenous anaesthesia (25,26). During halothane anaesthesia similar findings have been made in the dog (27), but not in man (28,29). Bahlman et a1 (29) compared halothane and nitrous oxidelhalothane at the same anaesthetic levels, expressed in multiples of MAC, and found less cardiodepression with the combination than with halothane alone.…”

Section: Nitrous Oxidesupporting

confidence: 54%

Halothane‐Relaxant Anaesthesia in Elderly Patients

Tokics

Brismar

Hedenstierna

1985

Acta Anaesthesiol Scand

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Twenty-three elderly patients, scheduled for elective cholecystectomy, were studied during halothane-relaxant anaesthesia. Anaesthesia was induced with thiopentone and maintained with halothane in 12 patients, six of whom had also received premedication. Eleven patients were anaesthetized with halothane, without thiopentone induction and with no premedication. Measurements of central haemodynamics were performed awake and during anaesthesia at end-tidal halothane concentrations of 0.5 and 1.0%; at the lower concentration, measurements were also made after addition of nitrous oxide. Premedication and thiopentone had no influence on the subsequent halothane anaesthesia. Halothane caused reductions of cardiac index, mean arterial blood pressure and oxygen uptake. However, neither right atrial nor pulmonary capillary venous pressure increased and the arterio-venous oxygen content difference decreased. These findings differ from those made by others in younger subjects and are probably attributable to a dose-dependent reduction in systemic vascular resistance. The addition of nitrous oxide had only minor effects on central circulation. The results suggest that the age of the patients influences their reaction to halothane anaesthesia.

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Section: Nitrous Oxidesupporting

confidence: 54%

Halothane‐Relaxant Anaesthesia in Elderly Patients

Tokics

Brismar

Hedenstierna

1985

Acta Anaesthesiol Scand

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“…In contrast, Smith and colleagues [14] were unable to report similar differences in skin blood flow when nitrous oxide was added to enflurane. These authors concluded that nitrous oxide does not stimulate the cardiovascular system in the presence of enflurane as it does when added to other inhalation agents such as halothane [15], ether [16] or fluroxene [17].…”

Section: Discussionmentioning

confidence: 99%

Effects of Enflurane and Isoflurane in Air-Oxygen on Changes in Thermal Balance During and After Surgery

Smith

Wood

et al. 1990

British Journal of Anaesthesia

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The temperatures in the aural canal (core), skeletal muscle and skin surface were measured during anaesthesia and surgery in 32 healthy females undergoing total abdominal hysterectomy and for 4 h after operation. The patients were allocated randomly to one of four groups according to the end-tidal concentration of volatile anaesthetic: 1 MAC isoflurane, 1 MAC enflurane, 1.8 MAC isoflurane and 1.8 MAC enflurane. The lungs were ventilated with an air-oxygen mixture. Neuromuscular block was produced with pancuronium. Room temperature and i.v. fluid administration were standardized. Aural canal, muscle and mean skin temperatures decreased significantly in all groups during surgery (P less than 0.001). The decrease in core and muscle temperatures, and mean body heat was significantly greater in the 1.8 MAC groups than in the 1 MAC groups for both volatile agents (P less than 0.001). However, there was a significantly greater decrease in core temperature and mean body heat in the isoflurane compared with the enflurane group (P less than 0.026). Body temperature returned to preoperative values during the recovery period. There was a significantly greater rate of rewarming during the first 1 h of recovery in the 1.8 MAC groups compared with the 1 MAC equivalent (P less than 0.001), and this was independent of the volatile agent used. The present results are compared with those reported previously in which nitrous oxide was added to the volatile agents. The decrease in body temperature depends upon the concentration of vapour used. However, it appears that isoflurane, without nitrous oxide, caused greater loss of body heat than enflurane.

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The cardiovascular responses to the addition of nitrous oxide to diethyl ether in man

Smith

EceR

Gregory

et al. 1972

Canad. Anaesth. Soc. J.

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IN MAN, THE ADDITION OF nitrous oxide to halothane-oxygen anaesthesia produces vasoconstriction and other signs of sympathetic activation. 1 One cannot say that this sympathetic activation is an independent effect of NzO rather than the result of an interdependent action of halothane and N20. Nitrous oxide is rarely used as the sole anaesthetic agent, but is commonly used with other agents, including diethyl ether. Therefore, the study of the interaction of N._,O with several different anaesthetic agents assumes clinical as weI1 as theoretical importance. In this investigation, we examined the effect of the addition of N_,O to diethyI ether, an anaesthetic agent with an entirely different cardiovascular and sympathetic response from that of halothane. METHODSEight fasting, unpremedicated healthy male volunteers, aged 21 to 34 years were studied. The investigation was approved by the human study committees of both medical schools. A detailed informed consent was obtained from each subiect.Methods used in this study have been published previously, J.2 but a brief description follows. Studies were begun early in the morning, following a 12-hour fast. Under local anaesthesia, catheters were placed into the brachial or radial arteries and into the right atrium. The position of the right atrial catheter was confirmed by observing a right ventricular pressure trace and then withdrawing the catheter slightly until the recording returned to venous levels. The following variables were recorded continuously1.2: arterial and right atrial pressures; electrocardiogram; phonocardiogram and external carotid pulse by microphones; end-tidal CO., and ether concentrations by infra-red analyzers; and skin (hand) and oral or oesophageal temperatures by thermistors.

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The Cardiovascular Responses to the Addition of Nitrous Oxide to Fluroxene in Man

Cited by 6 publications

References 4 publications

Halothane‐Relaxant Anaesthesia in Elderly Patients

Halothane‐Relaxant Anaesthesia in Elderly Patients

Effects of Enflurane and Isoflurane in Air-Oxygen on Changes in Thermal Balance During and After Surgery

The cardiovascular responses to the addition of nitrous oxide to diethyl ether in man

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