Showing papers in "BJA: British Journal of Anaesthesia in 1970"
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TL;DR: In this (unpremedicated) group of patients nearly half described waiting for surgery as the most unpleasant feature of their surgical experience, and postoperative pain was the major complaint in a further 20 per cent.
Abstract: SUMMARY An investigation is described into the problems of recall and dreaming under light anaesthesia with nitrous oxide, muscle relaxation being provided by tubocurarine, and the anaesthetic technique being, as far as possible, standardized. Tape-recorded music of two types was used to test the patient's ability to hear and, in addition, the nature and quality of dreams was investigated. There was no evidence that patients were able to hear the tape-recordings and there was no evidence of "awareness" during the operative procedure. Dreaming occurred in 44 per cent of the patients and details of the dreams were recalled in some two-thirds of these. Hypocapnia did not protect against dreaming. Patients who showed marked movement during the operative procedure were more liable to dream than those who did not; the significance of this movement is discussed. In this (unpremedicated) group of patients nearly half described waiting for surgery as the most unpleasant feature of their surgical experience, and postoperative pain was the major complaint in a further 20 per cent. The third commonest of the major complaints was related to requests to lift the head, etc., when unable to do so in the time immediately after operation, and this finding would seem to have some minor practical significance. Unpleasant dreams were the fourth commonest major complaint.
388 citations
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TL;DR: In twenty-two normotensive patients anaesthesia was induced with thiopentone, nitrous oxide and oxygen, suxamethonium, and endotracheal intubation, an average rise in mean arterial pressure of 25 mm Hg was observed.
Abstract: SUMMARY In twenty-two normotensive patients anaesthesia was induced with thiopentone, nitrous oxide and oxygen, suxamethonium, and endotracheal intubation. Laryngoscopy and insertion of an endotracheal tube were immediately followed by an average rise in mean arterial pressure of 25 mm Hg (SE 2.2, range 2–45). There was no significant difference in this response between groups premedicated with morphine and with amylobarbitone. There was no evidence that this effect caused lasting damage in normotensive patients. The possible cardiac or cerebral complications which might result in hypertensive patients are discussed.
285 citations
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TL;DR: It is suggested that the amplitude of the twitch response at a higher frequency expressed as a percentage of that at the slower rate may be useful in measuring degree of neuromuscular block in man.
Abstract: SUMMARY Study of the literature on the physiology of neuromuscular transmission suggested two new methods of assessing the degree of neuromuscular block in the human subject. These were, first, a comparison of the height of the recorded twitch tensions developed in response to repeated single stimuli applied at differing frequencies and, second, examination of the extent of reduction in amplitude of twitch tensions developed in response to a short train of four stimuli. In assessing the first method the use of three frequencies of stimulation was tried (i.e., 0.1 Hz (c.p.s.), 0.3 Hz and 1.0 Hz). It was found that as the frequency of stimulation was increased there was reduction in the amplitude of the recorded twitch response in curarized subjects, and that this reduction appeared to depend on the degree of curarization. In assessing the second method a short train of four stimuli at 2 Hz was used, and it was found that there was a progressive fade of successive recorded mechanical twitch responses in curarized subjects which again appeared to depend on the degree of curarization. It is suggested that the amplitude of the twitch response at a higher frequency expressed as a percentage of that at the slower rate, and the last response of the train of four expressed as a percentage of the first may be useful in measuring degree of neuromuscular block in man.
263 citations
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TL;DR: It is considered that the memory difficulties were not due to serious reduction of level of consciousness but do focus on the input or “consolidation” processes rather than on retrieval.
Abstract: SUMMARY A double-blind trial of intravenous diazepam (0.24 mg/kg) versus saline was carried out on twelve young intelligent male volunteers to examine the amnesic effect of the drug. Complex psychological testing extended over a 2-hour period. Dense anterograde amnesia was found for approximately 10 minutes with a less severe impairment of memory persisting at least half an hour after injection. It is considered that the memory difficulties were not due to serious reduction of level of consciousness but do focus on the input or “consolidation” processes rather than on retrieval. Further studies are needed to define more clearly the nature of the deficit.
177 citations
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TL;DR: In patients anaesthetized primarily with thiopentone there was no significant rise without surgery and the rise was, in general, proportional to the stress of surgery, the largest being during intra-abdominal operations.
Abstract: SUMMARY The rise in blood sugar during anaesthesia without surgery and during surface, thoracic and intra-abdominal surgery, was measured. In patients anaesthetized primarily with thiopentone there was no significant rise without surgery and the rise was, in general, proportional to the stress of surgery, the largest being during intra-abdominal operations. Findings were similar in another series of patients anaesthetized primarily with propanidid. Five anaesthetic techniques were also compared during intra-abdominal surgery. In all nitrous oxide and tubocurarine were used and there was a bigger rise in patients in whom anaesthesia was induced with propanidid than in those who had thiopentone. The addition of 1 per cent halothane or phenoperidine 5 mg to the thiopentone/nitrous oxide/tubocurarine technique, led to a significantly smaller response. When a technique using droperidol/fentanyl/tubocurarine was employed the hyperglycaemic response was similar to that with thiopentone induction.
154 citations
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TL;DR: The pressures exerted on the tracheal wall by cuffed endotracheal tubes were measured in patients on intermittent positive pressure ventilation and it was found that these pressures can easily be made excessive and sufficient to encouragetracheal necrosis.
Abstract: SUMMARY The pressures exerted on the tracheal wall by cuffed endotracheal tubes were measured in patients on intermittent positive pressure ventilation. It was found that these pressures can easily be made excessive and sufficient to encourage tracheal necrosis. These pressures exerted by the cuffs were not equally distributed around the tracheal circumference and varied also with the position of the head and with the level of consciousness.
139 citations
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TL;DR: The plasma cortisol level of patients anaesthetized for 1 hour with thiopentone and nitrous oxide was found to remain unchanged during body surface surgery, and during intra-abdominal surgery it rose to more than double the resting value.
Abstract: SUMMARY The plasma cortisol level of patients anaesthetized for 1 hour with thiopentone and nitrous oxide was found to remain unchanged. During body surface surgery it rose slightly, and during intra-abdominal surgery it rose to more than double the resting value. The blood sugar under the same circumstances changed in a qualitatively similar manner and the free fatty acids appeared to fall during anaesthesia without surgery, changed little during body surface surgery, and rose during intra-abdominal surgery. Plasma insulin during both types of surgery showed no significant change.
123 citations
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TL;DR: The addition of 0.5 per cent of halothane vapour to a basic thiopentone, nitrous oxide, muscle relaxant anaesthetic technique does not increase blood loss at Caesarean section, does not affect the incidence of hypotension, and is likely to ensure unconsciousness.
Abstract: SUMMARY The addition of 0.5 per cent of halothane vapour to a basic thiopentone, nitrous oxide, muscle relaxant anaesthetic technique does not increase blood loss at Caesarean section, does not affect the incidence of hypotension, and is likely to ensure unconsciousness. By permitting the administration of 50 per cent of oxygen with nitrous oxide, the condition of the newborn infant is likely to be improved. The use of 0.8 per cent of halothane vapour does not increase blood loss but is associated with a high incidence of hypotension and for this reason is not advisable.
123 citations
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TL;DR: Sodium nitroprusside given by intravenous drip has been used to control hypertensive crises since 1929 and its evanescent action makes it suitable for controlled hypotension during general anaesthesia.
Abstract: SUMMARY Sodium nitroprusside given by intravenous drip has been used to control hypertensive crises since 1929. Its evanescent action makes it suitable for controlled hypotension during general anaesthesia. Experience of its use in eighty-three cases is described, the drug being used during general anaesthesia with halothane. The patients were all undergoing surgery with the operating microscope, twenty-eight for hypophysectomy for secondary carcinoma. One death occurred in a severely ill patient with carcinomatosis which did not appear to be specifically related to the use of nitroprusside. In the other patients no adverse effects were seen and recovery to normal levels of blood pressure was rapid. The method of preparing the drug is described and it is suggested that it warrants further study in those cases where hypotensive anaesthesia is indicated.
94 citations
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TL;DR: The intravenous anaesthetic ketamine has been given to patients undergoing minor gynaecological surgery after atropine prcmedication in initial doses ranging from 1.0 to 3.0 mg/kg, with a high incidence of delirium at all dose levels.
Abstract: SUMMARY The intravenous anaesthetic ketamine has been given to patients undergoing minor gynaecological surgery after atropine prcmedication in initial doses ranging from 1.0 to 3.0 mg/kg. The chief induction complications were hypertension and hypertonus, the incidence of which was only broadly related to dosage. Recovery of consciousness was rapid, though marred by a high incidence of delirium at all dose levels. This delirium was sometimes sufficiently severe and prolonged as to necessitate tranquillization with diazepam. Hallucinations at this stage were so unpleasant that patient acceptance was much lower than with the barbiturates.
89 citations
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TL;DR: A brief consideration of the innervation of the larynx is presented as a prelude to a discussion of the significance in man of studies on laryngospasm in experimental animals.
Abstract: SUMMARY A brief consideration of the innervation of the larynx is presented as a prelude to a discussion of the significance in man of studies on laryngospasm in experimental animals. Particular attention has been paid to the forms of stimulation which lead to restriction of the airway in laryngospasm. Evidence implicating smell, nasal (trigeminal) irritation, buccal, pharyngeal, laryngeal and upper abdominal stimulation or manipulation has been reviewed. Both, the clinical significance of laryngospasm and conditions predisposing towards its occurrence have been discussed. Means of avoiding the occurrence of laryngospasm and methods of overcoming it once it has occurred have been reviewed.
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TL;DR: The effects of altering end-expiratory inflation pressure were studied in mechanically ventilated dogs in the normo, hypo- and hypervolaemic state, finding that the mean fall in cardiac output was smaller in the hyperVolaemic group than in the other two groups.
Abstract: SUMMARY The effects of altering end-expiratory inflation pressure were studied in mechanically ventilated dogs in the normo-, hypo- and hypervolaemic state. The mean fall in cardiac output resulting from an increase in end-expiratory pressure was smaller in the hypervolaemic group than in the other two groups. A positive end-expiratory pressure increased the mean deadspace/tidal volume ratio in all groups. A negative end-expiratory pressure increased venous admixture, particularly in the over-transfused animals, but the increase was not significant in the hypovolaemic group. A negative end-expiratory pressure did not affect deadspace/tidal volume ratio.
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TL;DR: The serum creatine phosphokinase levels have helped to establish the genetically-determined myopathic background of malignant hyperpyrexia.
Abstract: SUMMARY The familial aspects of malignant hyperpyrexia, are discussed and a method for identifying the asymptomatic carriers of this disorder presented. The serum creatine phosphokinase levels have helped to establish the genetically-determined myopathic background of this disorder. Ninety-nine members over four generations have so far been studied and data concerning sixty-nine are presented in this paper.
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TL;DR: The duration of analgesia and of hypoaesthesia produced by a variety of solutions has been examined by skin weal testing and bupivacaine was found to give significantly longer analgesia than prilocaine and significantly longer Hypoaesthesia than both the other agents.
Abstract: SUMMARY The duration of analgesia and of hypoaesthesia produced by a variety of solutions has been examined by skin weal testing; each separate study was carried out in twenty female volunteers under double-blind conditions. First, bupivacaine, lignocaine and prilocaine were compared with and without 1 in 200,000 adrenaline. Bupivacaine was found to give significantly longer analgesia than prilocaine and significantly longer hypoaesthesia than both the other agents. Adrenaline significantly lengthened the action of all three drugs, this prolongation being greatest with lignocaine. The second part of the trial compared the duration of action of hospital-prepared and commercially prepared solutions of the three local analgesics plus adrenaline. The commercial ampoule preparations provided significantly longer action than the corresponding drugs in hospital-prepared multidose vials. The third group of experiments studied the effect of doubling the concentrations of the solutions; there was no great increase in duration of analgesia but the duration of hypoaesthesia was lengthened, significantly so with bupivacaine. Throughout all the above studies the individual results with bupivacaine showed a greater range of variation than those with the other agents. Finally the analgesic effect of saline (with and without adrenaline) was investigated; it was found that both agents generally produced a similar brief period of hypoaesthesia. The findings and their practical implications are discussed.
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TL;DR: It is concluded that verapamil may be used safely for the control of supraventricular and ventricular dysrhythmias in lightly anaesthetized patients and its use is contraindicated in patients with atrioventricular block of any grade and in undigitalized patients with heart failure.
Abstract: SUMMARY The antidysrhythmic action of verapamil 20 mg was studied in 383 patients lightly anaesthetized with halothane in oxygen. The drug effectively inhibited ventricular and supraventricular dysrhythmias and was without effect on sinus tachycardia of adrenergic origins. Its possible modes of action have been discussed. It is suggested that it acts by preventing the function of calcium ions, thereby causing a non-specific inhibition of the cardiac dysrhythmic reactions to sympathetic overactivity. It is concluded that verapamil may be used safely for the control of supraventricular and ventricular dysrhythmias in lightly anaesthetized patients. Its use is contraindicated in patients with atrioventricular block of any grade and in undigitalized patients with heart failure.
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TL;DR: The mass factor of the enlarged uterus elevating the diaphragm appears to be the main cause for the antepartum decreases in total and chest wall compliance.
Abstract: SUMMARY Static total and lung compliance measurements were made in five healthy term-pregnant women immediately before and after vaginal delivery using a super-syringe and oesophageal balloon. Chest wall compliance was calculated from the formula of Comroe and associates (1962). The influence of supine recumbent v. lithotomy position was also evaluated and compared to five non-pregnant women. Following parturition, total and chest wall compliances increased significantly while lung compliance changes were variable and of smaller magnitude. In most patients, recumbent total and chest wall compliances were higher than lithotomy position values. The difference was greatest in the antepartum group and smallest in the control group. The mass factor of the enlarged uterus elevating the diaphragm appears to be the main cause for the antepartum decreases in total and chest wall compliance.
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TL;DR: The patient was treated successfully with aspiration of air, oxygen and positive pressure ventilation and the importance of a central venous catheter and an oesophageal stetho-scope is stressed.
Abstract: SUMMARY A case is reported of venous air embolism occurring during cervical laminectomy in the sitting position. The patient was treated successfully with aspiration of air, oxygen and positive pressure ventilation. The diagnostic features, prevention and treatment are discussed, and the importance of a central venous catheter and an oesophageal stetho-scope is stressed.
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TL;DR: Evidence has been presented to show that a second dose of suxamethonium is capable of producing a severe bradycardia in man, which may be effectively prevented by the prior administration of certain non-depolarizing muscle relaxants namely tubocurarine, alcuronium, c -toxiferine and pancuronium.
Abstract: SUMMARY Evidence has been presented to show that a second dose of suxamethonium is capable of producing a severe bradycardia in man. This response may be effectively prevented by the prior administration of certain non-depolarizing muscle relaxants namely tubocurarine, alcuronium, c -toxiferine and pancuronium in quantities of one-quarter or less of their muscle relaxant level. It is suggested that suxamethonium causes altered cardiac rhythm by stimulation of afferent vagal receptors, which action may be blocked by tubocurarine and similar drugs.
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TL;DR: Foetal Po2 was positively correlated with maternal Pao2 within the range 78 to 200–300 mm Hg, but was not correlated with further elevation of maternal P Sao2 from 200 to 500 mm HG.
Abstract: SUMMARY Fifteen cases of elective Caesarean section at term were studied under general anaesthesia. Maternal carbon dioxide tensions were controlled by adjusting the minute ventilation volume; Paco2 ranged from 13 to 80 mm Hg. Maternal oxygen tensions were controlled by changing the inspired oxygen concentrations (20, 33.3, 50, or 100 per cent); Pao2 ranged from 78 to 500 mm Hg. Umbilical vein Po2 and Pco2 of the newborn varied according to the maternal level. Foetal Pco2 was always higher than maternal Paoo2; the mean maternal-foetal gradient was 11.3 mm Hg (SD 4.7). Foetal Po2 was positively correlated with maternal Pao2 within the range 78 to 200–300 mm Hg, but was not correlated with further elevation of maternal Pao2 from 200 to 500 mm Hg. This might be attributed to the shape of Hbo2 dissociation curve.
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TL;DR: The decline in the total number of anaesthetic deaths during the previous decade has been abruptly reversed, in contrast to the continued overall decline in maternal mortality.
Abstract: Triennially, since 1954, the Ministry of Health has issued a Report concerning maternal deaths which occurred in England and Wales during the previous three years. The current Report on Confidential Enquiries into Maternal Deaths in England and Wales, 1964-66* makes depressing reading for anaesthetists. Virtually alone of the factors associated with maternal deaths, the number applied to anaesthesia was greater in 1964-66 than in 1961-63, and this rise was "proportionally greater than the increase in the number of births during the same period". It was also proportionally greater than the increase in the number of Caesarean sections (approximately 17 per cent). The decline in the total number of anaesthetic deaths during the previous decade has been abruptly reversed, in contrast to the continued overall decline in maternal mortality (table I).
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TL;DR: Investigations with chloroform anaesthesia in rats pretreated with phenobarbitone indicate that the hepatotoxic action of chloroforms is directly related to the activity of the microsomal drug-metabolizing enzymes.
Abstract: SUMMARY Investigations with chloroform anaesthesia in rats pretreated with phenobarbitone indicate that the hepatotoxic action of chloroform is directly related to the activity of the microsomal drug-metabolizing enzymes. Pretreatment with disulfiram, an inhibitor of the enzymes in man and rats, completely prevents the hepatotoxicity of chloroform in rats. It would seem that the toxic effects of chloroform on the liver are due to toxic metabolites, the nature of which remains unknown. The enzymes responsible for the production of the toxins appear to be located in the centre of the hepatic acinus.
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TL;DR: Pentazocine, pethidine and fentanyl exert different haemodynamic effects in conscious and anaesthetized subjects, and all three analgesics caused a 20–25 per cent fall in blood pressure and heart rate in anaesthenized patients.
Abstract: SUMMARY The cardiovascular responses to five sequential intravenous injections of pentazocine (5×0.6 mg/kg), fentanyl (5×0.001 mg/kg) and pethidine (5×1.0 mg/kg) were assessed in conscious and anaesthetized subjects. In conscious volunteers pentazocine raised the systolic pressure by 30 per cent. Pentazocine and pethidine raised the diastolic pressure by 10 per cent and the heart rate by 15 per cent; with pethidine the increases were not sustained but tended to fluctuate. Fentanyl did not affect the pressure or heart rate. In anaesthetized patients, all three analgesics caused a 20–25 per cent fall in blood pressure and heart rate, fluctuations in pressures occurring in the pentazocine and pethidine group. No changes of e.c.g. pattern were observed. Pentazocine, pethidine and fentanyl thus exert different haemodynamic effects in conscious and anaesthetized subjects.
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TL;DR: There was no significant change of mean arterial pressure in either series of patients; therefore the fall of cardiac output was accompanied by a compensatory increase of total peripheral resistance.
Abstract: SUMMARY We have investigated the effects of alcuronium (0.15 mg/kg body weight) on heart rate, stroke volume, cardiac output, mean arterial blood pressure and total peripheral resistance in 22 artificially ventilated patients anaesthetized with 60 per cent nitrous oxide in oxygen, plus either tubocurarine (25–35 mg, according to body weight) and 0.2 per cent methoxyflurane—series I—or phenoperidine (1 mg/15 kg body weight)—series II. End-tidal Pco2 was maintained constant. The most striking effect was a significant increase of heart rate in the series II patients, accompanied by a significant fall of cardiac output and of stroke volume. There was no significant change of mean arterial pressure in either series of patients; therefore the fall of cardiac output was accompanied by a compensatory increase of total peripheral resistance.
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TL;DR: Droperidol caused less hypnosis than either morphine or diazepam, and its use was associated with a much higher incidence of anxiety among patients than was observed in the group who had received saline only, but there was no evidence of any gross effect on cardiovascular system stability.
Abstract: SUMMARY Droperidol 5 mg and 10 mg and diazepam 10 mg were compared in premedication studies with morphine 10 mg and saline. Droperidol caused less hypnosis than either morphine or diazepam, and its use was associated with a much higher incidence of anxiety among patients than was observed in the group who had received saline only. Dizziness and restlessness were also significant features of the action of droperidol. There was no evidence of any gross effect on cardiovascular system stability. The incidence of sickness following droperidol was similar to that in the saline and diazepam groups.
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TL;DR: Changes in cardiorespiratory function resulting from haemorrhage and overtransfusion were measured in dogs during controlled ventilation and there were significant reductions in arterial Pco2, carbon dioxide output and oxygen consumption, cardiac output and total venous admixture.
Abstract: SUMMARY Changes in cardiorespiratory function resulting from haemorrhage and overtransfusion were measured in forty-seven dogs during controlled ventilation. In the animals bled to a mean arterial pressure of 70 mm Hg there were significant reductions in arterial Pco2, carbon dioxide output and oxygen consumption, cardiac output and total venous admixture. In the animals transfused to a mean central venous pressure of 15 mm Hg there was a significant fall in total thoracic compliance and arterial Po3 and significant increases in the alveolar-arterial Po3, difference and carbon dioxide output.
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TL;DR: The maintenance of normal pH during the operation, or the inclusion of a period of normothermia before cooling, had no measurable effect on the postoperative acid-base state or clinical course as compared with the usual routine of bypass in respiratory alkalosis and with immediate cooling.
Abstract: SUMMARY Twenty-two patients undergoing open-heart surgery with cardiopulmonary bypass have been studied to define acid-base changes associated with anaesthesia, bypass, hypothermia and recovery. The maintenance of normal pH during the operation, or the inclusion of a period of normothermia before cooling, had no measurable effect on the postoperative acid-base state or clinical course as compared with the usual routine of bypass in respiratory alkalosis and with immediate cooling. Lactate and pyruvate increased slowly throughout anaesthesia and bypass to combined levels not exceeding 5 m.equiv/1. Rapid metabolic acid-base shifts of at least equal magnitude, not due to lactic or pyruvic acids, were apparently associated mainly with temperature changes. Acidosis has not been found severe enough to need routine administration of bicarbonate at any stage.
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TL;DR: The neuromuscular blocking action of pancuronium bromide was investigated in anaesthetized patients and it was found that during recovery from the action of the drug a respiratory acidaemia reduced and a respiratory alkalaemia increased the rate of recovery.
Abstract: SUMMARY The neuromuscular blocking action of pancuronium bromide was investigated in anaesthetized patients. Pancuronium resembles tubocurarine in producing a competitive type block but is about five times as potent as tubocurarine. With a small dose (0.02 mg/kg) the onset of action of the drug was slow, with the time to its maximum effect averaging 4.5 minutes. The maximum effect was, on average, a reduction in twitch height of 69 per cent. With larger doses of the agent (0.05 mg/kg and 0.1 mg/kg) the onset was more rapid and usually a complete block was achieved. The recovery from 0.02 mg/kg and 0.05 mg/kg to 50 per cent of the initial twitch height averaged 12.2 minutes and 36.8 minutes respectively. Repeated doses of the drug produced a greater duration of action with a somewhat greater intensity of block. During recovery from the action of the drug a respiratory acidaemia reduced and a respiratory alkalaemia increased the rate of recovery.
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TL;DR: The metoclopramide-treated group had significantly less nausea, retching and vomiting than the perphenazine- treated group in a double-blind trial on 188 women undergoing planned gynaecological laparotomies.
Abstract: SUMMARY Metoclopramide 10 mg and perphenazine 5 mg were compared in a double-blind trial on 188 women undergoing planned gynaecological laparotomies. Metoclopramide or perphenazine was given intramuscularly at the end of the operation, and the patients were observed for 6 hours in the recovery ward. The metoclopramide-treated group had significantly less nausea, retching and vomiting than the perphenazine-treated group. The difference was significant at the 0.5 per cent level when comparing the “nausea-score” of the two groups by a Wilcoxon-Mann-Whitney test, at the 2.5 per cent level when comparing the incidence of retching and vomiting in the two groups by a λ2 test. The awakening time was slightly longer in the metoclopramide-treated group than in the perphenazine-treated group. There was no significant effect on blood pressure or pulse rate in either group. A significantly lower incidence of pethidine injections was noted in the metoclopramide-treated group than in the perphenazine-treated group. This has no effect on the conclusion that metoclopramide 10 mg is more effective in preventing postoperative nausea and vomiting than perphenazine 5 mg.