Comparison of Electrocardiographic Changes during Microlaryngoscopy under Balanced Anaesthesia Induced by Althesin or Thiopentone

Electrocardiographic (ECG) changes during microlaryngoscopy were studied with three methods of anaesthesia. In the two main groups, balanced anaesthesia was induced by Althesin (=Althesin I group) in 98 patients or by thiopentone (=thiopentone group) in 68 patients. In 23 patients, halothane anaesthesia was induced by Althesin (= Althesin II group). During the procedure, the most common ECG changes in all groups were sinus tachycardia (54–78%), junctional rhythm (28–57%), ventricular ectopic beats (12–26%), T-wave changes (9–22 %) and supra ventricular ectopic beats (7–17%). There was no statistically significant difference in the total number of ECGchanges between the groups. There was, however, significantly more sinus tachycardia in the Althesin II group (78%) than in the thiopentone group (54%). Junctional rhythm occurred significantly more often in the Althesin II group (57%) than in the Althesin I group (31 % ) or in the thiopentone group (28%). Upper junctional rhythm was most common in the Althesin I group, whereas middle junctional rhythm dominated in the Althesin II group. Ischaemic S-T segment depression did not occur in the thiopentone group, whereas in the Althesin I and II groups its incidence ranged from 6 to 13%. In all patients ECG changes disappeared without any special treatment after the manipulation of the vocal cords. The results suggest that there is no decisive difference in the occurrence of ECG changes between the three methods of anaesthesia.     

Electrocardiographic Changes During Microlaryngoscopy Under Halothane Anaesthesia

An 82 nicht ausgewählten aufeinanderfolgenden Patienten wurde die Häufigkeit von EKG-Veränderungen während mikrolaryngoskopischer Eingriffe unter Halothannarkose untersucht. 12 Patienten hatten Coronarerkrankungen.
EKG-Veränderungen traten bei 42% aller Patienten auf. Die häufigsten EKG-Veränderungen in der coronar-gesunden Gruppe waren mit 20% ventrikuläre Extrasystolen. In der coronar-kranken Gruppe waren rasch ansteigende S-T-Strecken-Senkungen mit 33% am häufigsten. Andere Veränderungen, die während des Eingriffes bei den Coronar-Gesunden gesehen wur-den, waren verschiedene Typen von S-T-Senkungen, intraventrikulare Leitungsstörungen, Verflachung oder Umkehr der T-Welle, Sinusbradycardie und supra-ventrikuläre Tachycardie, sowie bei der Gruppe der Coronar-Kranken verschiedene Typen von S-T-Sen-kungen, T-Wellen-Verflachung oder -umkehr und supraventrikuläre oder ventrikuläre Extrasystolen. Bei den Patienten beider Gruppen lagen alle diese anderen Veränderungen unter 10%. Abgesehen von dem Eingriff wurden einige EKG-Veränderungen auch während der Intubation beobachtet. Die EKG-Veränderungen verschwanden nach den Manipulationen an den Stimmbändern oder nach der Intubation ohne besondere Behandlung.
EKG-Veränderungen, insbesondere Extrasystolen, könnten über das sympathische Nervensystem ausgelöst werden, da sie mit erhöhter Herzfrequenz einhergingen.     

Gastro‐Oesophageal Reflux during Thiopentone or Propofol Anaesthesia in the Cat

Lower oesophageal pH was monitored in 50 cats anaesthetized with either thiopentone or propofol. Gastro‐oesophageal reflux, as evidenced by a decrease in lower oesophageal pH to less than 4.0 or an increase to more than 7.5, occurred in 16 % (4/25) and 12 % (3/25) of the cats anaesthetized with thiopentone and propofol, respectively, the difference between the two groups being non‐significant. Reflux usually occurred shortly after the induction of anaesthesia and had a mean duration of about 23 min. The refluxate was always acidic (pH < 4.0). Gastric contents of pH below 2.5 were refluxed on three occasions, two in the thiopentone group and one in the propofol group. Regurgitation and flow of gastric contents from the mouth occurred in only one cat anaesthetized with propofol. None of the cats that exhibited reflux developed any signs of post‐anaesthetic oesophagitis or stricture formation.     

Psychological Changes in Children after Anaesthesia: A Comparison between Halothane and Ketamine

The psychological reactions to hospitalization, anaesthesia, and operation in a group of 107 children from 1 to 12 years old, anaesthetized with ketamine or halothane after randomization were investigated through questionnaires, which the parents answered 1 month postoperatively. The percentage of replies was 96.3%. Fifty-three children were anaesthetized with ketamine and 50 with halothane. Thirteen children in the ketamine group and nine in the halothane group reacted with negative personality changes; the reactions were of less than 1 month's duration and were most frequent in the youngest children. The parents' preparation of the children had no influence on the results. The number of personality changes caused by the two anaesthetic agents did not differ significantly. Furthermore, the investigation showed the nine children reacted for the better. Thirty-six per cent of the parents felt insufficiently informed of what the hospitalization implied for their child.     

Heart Rate Changes Caused by Enflurane and Halothane Anaesthesia in Man

Changes in heart rate and arterial pressure caused by enflurane and halothane anaesthesia were investigated in patients premedicated with diazepam and scopolamine. Enflurane caused a significant (12%) increase in heart rate and depression of arterial pressure (23%). Halothane depressed heart rate significantly (14%), whereas arterial pressure was unaffected. The authors conclude that enflurane possesses a positive chronotropic effect.     

Haemodynamic Changes during Sodium Nitroprusside Induced Hypotension and Halothane/Nitrous Oxide Anaesthesia

The haemodynamic effects of nitroprusside (SNP) were studied in six patients undergoing surgery for intracranial aneurysm under controlled hypotension in endotracheal anaesthesia with halothane-nitrous oxide during hypocapnia. Mean arterial pressure was reduced with SNP from mean 12.25 kPa to mean 8.29 kPa (32%). There were concomitant statistically significant decreases in systemic vascular resistance (-21%), cardiac index (-17%), stroke index (-23%), pulmonary arterial mean pressure (-27%) and pulmonary capillary wedge pressure (-27%). Heart rate, central venous pressure and pulmonary vascular resistance did not change significantly. After the infusion of SNP was discontinued all parameters, except cardiac index and heart rate, returned to values not significantly different from the control values. The hypotension induced by SNP resulted from reductions in cardiac index and systemic vascular resistance. The reduction in cardiac index did not reach a critical level in any of the patients.     

Midazolam for Induction of Anaesthesia in Outpatients: A Comparison with Thiopentone

Midazolam, a new water-soluble benzodiazepine, with an elimination half-life of approximately 2 h, was compared with thiopentone for induction of general Anaesthesia in a randomized, single-blind study. The patients were 60 healthy women undergoing legal abortion as outpatients. Midazolam provided smooth and reliable induction of Anaesthesia with few side-effects. However, the induction time was considerably longer in the midazolam group (82.3 + 6.1) than in the thiopentone group (45.9 ±1.7 s). The dose of midazolam required for induction was 0.36±0.01 mg/kg, while that of thiopentone was 6.43 ±0.21 mg/kg. Apnoea occurred with a frequency of 10 % in the midazolam group and 55 % in the thiopentone group, but was of equal duration in both groups. Circulatory conditions were more stable during induction with midazolam, with a slower fall in blood pressure and no change in heart rate. The patients were breathing O₂/N₂O in proportions of 1:2.
To ensure adequate surgical anaesthesia, it was necessary to add halothane for short periods for all patients in the midazolam group and for 79% of the thiopentone group. Postoperatively, all patients who had received midazolam, but none induced with thiopentone, had anterograde amnesia; this lasted for more than 1 h. All patients in both groups could leave the hospital after routine postoperative observation for 3–4 h. Venous tolerance was good for both drugs.     

The Potentiation of Halothane Anaesthesia by Clonidine

The antihypertensive agent, clonidine, has a marked sedative effect. We studied whether clonidine also deepens halothane anaesthesia. Eight rabbits were anaesthetized with and without clonidine premedication in a cross-over study. Clonidine premedication (50 microgram/kg subcutaneously) was administered three times daily for 3 days. Tolerance to pain during halothane anaesthesia was tested by compressing the ear with a vessel clamp. Halothane concentrations were determined by gas chromatography. The rabbits premedicated with clonidine tolerated painful stimuli without reactions at lower halothane concentrations in arterial blood and inspired air than unpremedicated rabbits. MAC calculated from blood concentrations was 1.29% for unpremedicated and 1.09% for clonidine-premedicated rabbits. The results suggest that clonidine diminishes the anaesthetic requirement in halothane anaesthesia.     

Comparison of Halothane and Enflurane Anaesthesia for Tonsillectomy in Adults

Halothane and enflurane in combination with N₂O/O₂ were compared in 103 adults undergoing tonsillectomy. Anaesthesia was induced with thiopental, and intubation was facilitated with suxamethonium. During halothane anaesthesia the mean heart rate ranged from 91 to 106 beats/min and the mean systolic arterial pressure from 111 to 127 mmHg. The values did not diifer significantly from the corresponding values during enflurane anaesthesia. Electrocardiographic changes occurred in 56% and 31% of the patients anaesthetized with halothane or enflurane, respectively. The incidence of junctional rhythm, the most common ECG change, was 46% in the halothane group and 29% in the enflurane group. 19% of the patients in the halothane group and 31% in the enflurane group responded to surgical stimulus by swallowing or coughing. The responses were mostly short-lasting and did not much disturb the surgeon. The incidence of laryngospasm was 6% after halothane and 2% after enflurane anaesthesia. The mean total recovery score (0—10) was 6.1 after halothane and 6.3 after enflurane at arrival in the recovery room and 9.8 in both groups 30 min later. After halothane, nausea and vomiting occurred in 8 and 12% of the patients, respectively. The corresponding figures after enflurane were 2 and 8%. It is concluded that both halothane and enflurane arc suitable anaesthetics for tonsillectomy in adults. The most striking difference between the anaesthetics was the significantly more common occurrence of ECG changes during halothane than enflurane anaesthesia.     

Comparison of Alfentanil and Fentanyl as Supplements to Induction of Anaesthesia with Thiopentone

In 120 premedicated patients undergoing general surgery, anaesthesia was induced with thiopentone 3 mg kg-1, preceded by alfentanil 4.5, 9.0 or 13.5 micrograms kg-1 or fentanyl 1.5 micrograms kg-1. The largest alfentanil dose attenuated the arterial blood pressure response to laryngoscopy and intubation better than the smaller doses of alfentanil. Changes in frontal muscle electromyogram or plasma cortisol and prolactin levels were not dependent on the adjuvant used. After thiopentone, 30, 7 and 17% of the patients given alfentanil 9.0 and 13.5 micrograms kg-1 and fentanyl 1.5 micrograms kg-1, respectively, reacted to pinching of the lower abdomen. Patients given alfentanil 4.5 micrograms kg-1 did not tolerate the endotracheal tube after recovery from suxamethonium block and their heart rate was increased 12 min after alfentanil administration. We conclude that the antinociceptive effect of alfentanil is distinctly shorter than that of fentanyl. The analgesic potency of alfentanil is between one sixth and one ninth of that of fentanyl.     

Comparison of Thiopentone and Diazepam as Induction Agents of Anaesthesia for Caesarean Section

Clinical effects of thiopentone (3 mg/kg body weight) and diazepam (0.3 mg/kg) were compared for elective caesarean sections in two groups of 43 and 39 women, respectively. They were given general anaesthesia in left lateral tilt. The systolic, diastolic and mean arterial pressures were moderately elevated at onset of surgery in both groups, probably indicating light anaesthesia. Later, a gradual decrease to the preinduction levels was observed. The mean injection-delivery (I-D) interval was 344 s in the thiopentone group and 339 s in the diazepam group. The I-D intervals were shorter than 10 min in 39 of the cases in the thiopentone group and 38 cases in the diazepam group. Low Apgar scores at 1 min (6 or less) occurred in five of the neonates in each group, while all had normal Apgar scores at 5 min (7 or more). Asjudged by the Apgar scores and the acid-base status of umbilical cord blood, the effects of the induction agents on the neonatal condition were indistinguishable in the two groups. In the thiopentone group, unpleasant recollections were reported in 5 out of 40 patients (12.5%), compared to none in the diazepam group. Diazepam-nitrous oxide anaesthesia is well accepted by the mothers and is an alternative to supplementing thiopentone induction with a volatile gas for patients who have previously experienced wakefulness or express fear of awareness. The main drawback with diazepam induction, however, is the slow induction of sleep. Harmful drug effects on the neonates must be expected if the dose has to be increased in order to ensure sleep.     

Cardiac Arrhythmias in Non-intubated Children during Adenoidectomy. A Comparison between Enflurane and Halothane Anaesthesia

The incidence of cardiac arrhythmias, heart rate, blood pressure, capillary perfusion and end-tidal CO2 tension were studied in 167 healthy children 1-12 years of age undergoing adenoidectomy (n = 82) and myringotomy (n = 85) during enflurane and halothane anaesthesia. The incidence of cardiac arrhythmias was significantly lower during myringotomy than during adenoidectomy. In children undergoing adenoidectomy the incidence of arrhythmias was 38.9% during enflurane anaesthesia and 86.6% during halothane anaesthesia (P less than 0.001). In the halothane group ventricular arrhythmias were observed in 19 patients (41.3%) but only in one child (2.8%) in the enflurane group. The ventricular arrhythmias seen during halothane anaesthesia were unifocal in six patients and multifocal in five and classified as ventricular tachycardia in eight children. Heart rate was increased by about 40% at the onset of ventricular arrhythmias. The heart rate remained unchanged with enflurane anaesthesia during surgery, which may reflect a decreased sympathomimetic activity. It is suggested that the low incidence of ventricular arrhythmias during enflurane anaesthesia may be explained by the combination of a reduced sympathomimetic activity and a lowered susceptibility of the myocardium to the actions of endogenous catecholamines.     

The Cardiovascular Effects of Pancuronium during Halothane and Cyclopropane Anaesthesia

The effects of pancuronium 0.1 mg/kg i.v. on heart rate (HR) and mean arterial blood pressure were investigated in two groups of eight patients, each receiving inhalational anaesthesia with either halothane or cyclopropane. A more pronounced effect on HR in the cyclopropane group with a mean increase of 104% occurred. The mean increase in the halothane group was 54%. There was a statistically significant difference (P<0.05) between the HR increases. The vagolytic effect of pancuronium and the influence of halothane and cyclopropane on the autonomic nervous system are discussed.     

Hepatic Effects of Halothane,Isoflurane or Sevoflurane Anaesthesia in Dogs

The effects of halothane, isoflurane and sevoflurane anaesthesia on hepatic function and hepatocellular damage were investigated in dogs, comparing the activity of hepatic enzymes and bilirubin concentration in serum. An experimental study was designed. Twenty‐one clinically normal mongrel dogs were divided into three groups and accordingly anaesthetized with halothane (n = 7), isoflurane (n = 7) and sevoflurane (n = 7). The dogs were 1–4 years old, and weighed between 13.5 and 27 kg (18.4 ± 3.9). Xylazine HCI (1–2 mg/kg) i.m. was used as pre‐anaesthetic medication. Anaesthesia was induced with propofol 2 mg/kg i.v. The trachea was intubated and anaesthesia maintained with halothane, isoflurane or sevoflurane in oxygen at concentrations of 1.35, 2 and 3%, respectively. Intermittent positive pressure ventilation (tidal volume, 15 ml/kg; respiration rate, 12–14/min) was started immediately after intubation and the anaesthesia lasted for 60 min. Venous blood samples were collected before pre‐medication, 24 and 48 h, and 7 and 14 days after anaesthesia. Serum level of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and gamma‐glutamyltransferase (GGT), lactate dehydrogenase (LDH GGT) activities and bilirubin concentration were measured. Serum AST, ALT and GGT activities increased after anaesthesia in all groups. In the halothane group, serum AST and ALT activities significantly increased all the time after anaesthesia compared with baseline activities. But in the isoflurane group AST and ALT activities increased only between 2 and 7 days, and in the sevoflurane group 7 days after anaesthesia. GGT activity was increased in the halothane group between 2 and 7 days, and in the isoflurane and sevoflurane groups 7 days after anaesthesia. All dogs recovered from anaesthesia without complications and none developed clinical signs of hepatic damage within 14 days. The results suggest that the use of halothane anaesthesia induces an elevation of serum activities of liver enzymes more frequently than isoflurane or sevoflurane from 2 to 14 days after anaesthesia in dogs. The effects of isoflurane or sevoflurane anaesthesia on the liver in dogs is safer than halothane anaesthesia in dogs.     

Circulatory Effects of Renin-Angiotensin System Antagonists during Halothane Anaesthesia in Hypertensive Rats

The circulatory effects of captopril, an angiotensin I-converting enzyme inhibitor, and saralasin, a competitive angiotensin II antagonist, were studied during halothane anaesthesia in spontaneously hypertensive (SH) rats. Captopril decreased blood pressure significantly in unanaesthetized rats. Pretreatment with indomethacin, a prostaglandin synthesis inhibitor, did not modify the antihypertensive action of captopril. During 1 MAC halothane anaesthesia, the mean arterial pressure (MAP) in unmedicated SH control rats was maintained at a relatively high level (16.2 ± 0.7 kPa, mean ± s.c. mean), while in captopril-treated rats MAP decreased to 8.8 ± 1.1 kPa. Indomethacin somewhat inhibited MAP decrease in the caplopril-medicated group. Saralasin infusion in halothane-anaesthetized rats decreased MAP in the same way as captopril alone. The tolerance to haemorrhagic shock was markedly impaired in rats receiving captopril or saralasin, compared to untreated controls. During halothane anaesthesia, the plasma renin activities in the captopril, captopril + indomethacin, and saralasin groups were significantly higher than in untreated animals. Plasma kininogen was unaffected by any of the medications. The results suggest that the renin-angiotensin system is important in maintaining blood pressure in halothane anaesthesia, and that the tolerance to haemorrhagic shock is particularly impaired by drugs inhibiting the renin-angiotensin system.     

Comparison of Fentanyl and Halothane as Supplement to Nitrous-Oxide-Oxygen Anaesthesia for Coronary Artery Surgery

Twenty unselected patients suffering from incapacitating angina, in spite of medication with nitrates, beta-blockers and calcium antagonists, were studied before and during coronary artery bypass surgery. Fentanyl or halothane was randomly used in combination with nitrous oxide for maintenance of anaesthesia in order to compare the haemodynamic response to surgery and cardiopulmonary bypass with these two anaesthetic regimens. Systemic and pulmonary artery pressure were kept within normal limits with the aid of volume replacement and/or nitroprusside. The haemodynamic response to surgery and bypass was benign and almost identical in the two groups. Cardiac index increased markedly after bypass (P less than 0.02-0.001) from 2.0 to 3.0 1 X min-1 X m-2 due to an increase in heart rate with no change in stroke index (40 ml X m-2). Oxygen delivery remained unchanged at 17 mmol X min-1 X m-2 in spite of a marked reduction in blood erythrocyte volume fraction (B-EVF), from 38% before bypass to 24% after bypass (P less than 0.001). Oxygen uptake remained unchanged until the end of surgery and did not differ between the groups. Systemic vascular resistance, corrected for the change in viscosity due to the altered B-EVF, was unchanged during the study. No difference was observed between the groups in the relation between pulmonary artery diastolic pressure and left ventricular stroke work index or stroke index, either before or at the end of cardiopulmonary bypass when the patients were transfused from the oxygenator.     

Maternal Haemodynamic Changes during Caesarean Section: A Comparison of Epidural and General Anaesthesia

Haemodynamic measurements were performed on 20 healthy women before and during elective caesarean section under epidural (10 women) or general anaesthesia (10 women). The influence of the two anaesthetic techniques on the haemodynamic changes associated with operative delivery was compared. The following haemodynamic variables were studied: cardiac output (CO), stroke volume (SV) determined non-invasively with impedance cardiography, heart rate (HR), systolic (SBP) and diastolic blood pressure (DBP), pulse pressure, mean arterial pressure (MAP) and total peripheral vascular resistance (TPR). During epidural anaesthesia, SV was largely unchanged before delivery but increased (P less than 0.05) following delivery. However, CO increased (P less than 0.05) prior to delivery due to an increase (P less than 0.01) in HR. A further increase (P less than 0.05) in CO was recorded following delivery. SBP, DBP, MAP and TPR decreased (P less than 0.01) during epidural anaesthesia. In the patients undergoing general anaesthesia, SV decreased (P less than 0.05) prior to delivery. However, CO remained largely unchanged due to an increase (P less than 0.01) in HR. Following delivery, CO (P less than 0.05) and SV (P less than 0.01) increased whereas HR decreased (P less than 0.01). SBP, DBP and MAP increased (P less than 0.01) prior to delivery, returning to the same level as prior to induction of anaesthesia following delivery. TPR was largely unchanged prior to delivery but decreased (P less than 0.01) following delivery.     

氟烷和氯胺酮麻醉下脑静脉血氧分压和氧含量的变化

本研究选择ＡＳＡＩ～Ⅱ级，行腹部手术的成年病人２５例，随机分为氟烷组（１４例）和氯胺酮组（１１例）分别于麻醉前，麻醉后３０ｍｉｎ和６０ｍｉｎ同时采取动脉血和颈内静脉血进行血气分析。结果：两组间动脉氧分压和氧含量无显著差异（Ｐ〉０．０５）；两组间颈内静脉血氧分压和氧含量在麻醉前差异不显著，在麻醉后差异显著（Ｐ〈０．０５）或十分显著（Ｐ〈０．０１）。说明氟烷可使脑耗量降低，而氯胺酮则否。