Recovery times following induction of anaesthesia with propofol, methohexitone, enflurane or thiopentone in children

We have measured the times to early recovery in forty children aged 3-14 years in whom anaesthesia was induced by intravenous propofol, methohexitone, thiopentone or inhalation of enflurane. Maintenance anaesthesia consisted of inhalation of nitrous oxide, oxygen and enflurane via a face mask. Early recovery, assessed by the Steward recovery score, was significantly faster after propofol, methohexitone or inhalation of enflurane compared with thiopentone (P < 0.01). There were no significant differences in recovery times between propofol, methohexitone or enflurane. We conclude that the use of propofol to induce anaesthesia does not hasten recovery in children undergoing short day-case procedures compared with methohexitone or inhalation of enflurane.     

Outpatient paediatric dental anaesthesia

One hundred and fifty unpremedicated children who presented for dental extractions were anaesthetised with nitrous oxide and halothane, enflurane or isoflurane. Ventricular arrhythmias occurred only in the halothane group (14%). Respiratory problems and desaturation were significantly more common in the isoflurane group. Induction times differed significantly between the groups halothane less than enflurane less than isoflurane, while recovery time and induction to recovery time were significantly shorter in the enflurane group. We suggest that enflurane is the most suitable agent for anaesthetising these patients.     

A comparison of alfentanil, halothane and enflurane as supplements for outpatient urological surgery

Seventy-seven patients presenting for outpatient cystoscopy participated in a trial to assess postoperative recovery when either alfentanil, halothane, or enflurane were used in combination with nitrous oxide/oxygen anaesthesia. Anaesthesia was uneventful in all cases. Apnoea occurred once with alfentanil, but naloxone was not required. Vomiting occurred once with alfentanil and once with enflurane. Anti-emetics were not required. Blood pressure and pulse rate variations from preoperative levels occurred with similar frequency in all groups. Times to open eyes, show left thumb, and give correct date of birth were significantly less with alfentanil than with the other agents tested. Trieger testing failed to demonstrate an advantage of alfentanil, although two patients in each of the halothane and enflurane groups were insufficiently recovered to complete the tests. As tested, alfentanil represents a useful alternative to halothane or enflurane as postoperative recovery of mental function is significantly more rapid than with the inhalational agents.     

回路内麻醉气体吸附器的临床应用

目的在吸入麻醉术后恢复阶段,观察回路内麻醉气体吸附器是否可缩短吸入麻醉的苏醒时间。方法在固定潮气量、每分通气量和新鲜气体流量的条件下,术毕关闭挥发罐后,比较使用回路内麻醉气体吸附装置对回路内麻醉气体浓度变化的影响。结果使用吸附器后,回路内麻醉气体浓度降至MAC0．3所需时间,异氟醚由20．0±0．3分钟降至3．3±0．5分钟(P＜0．01)。安氟醚由25．0±0．1分钟降至3．5±0．5分钟(P＜0．01)。结论应用回路内麻醉气体吸附器可显著缩短病人苏醒时间,并减少气源浪费和环境污染。     

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.     

Low-concentration enflurane:study of anesthetic stability and quality of recovery

The stability of anaesthesia and the quality of recovery obtained with low doses of enflurane were studied. Two groups of 20 patients operated for lumbar slipped disc were compared. The mean age and weight distribution of the two groups were not statistically different. Induction was the same in the two groups (diazepam, fentanyl, pancuronium and nitrous oxide). In one group, enflurane (0.4%) was added with controlled ventilation. Thiopentone was added if some spontaneous movements were observed, if arterial pressure and heart rate increased, and if the digital plethysmograph curve decreased. The quality of recovery was assessed by number-connection tests 1 and 2 h after the end of anaesthesia. Thiopentone was required five times in the group without enflurane, whilst it was never used in the group with enflurane. This difference was statistically significant (p less than 0.01) and showed a more important stability of anaesthesia when enflurane (0.4%) was used. No statistically significant difference was found in the recovery scores between the two groups 1 and 2 h after the end of anaesthesia. It was proposed that low doses of enflurane were sufficient to increase the effects of the other anaesthetic drugs without any residual effect on recovery. Low doses of enflurane could be used during anaesthesia induced with fentanyl and diazepam, giving better stability during anaesthesia without any pernicious effects on recovery.     

Comparative clinical study of induction and emergence time in sevoflurane and enflurane anaesthesia

The induction and emergence times in patients who received minor oral surgery under sevoflurane with nitrous oxide or enflurane with nitrous oxide were compared. The induction time required for the loss of eyelid reflex when using sevoflurane (1.6 +/- 0.2 min) was significantly shorter than that in the enflurane group (2.9 +/- 0.4 min). There was no significant difference in the recovery time in the two groups.     

Randomized comparison of outcome after propofol-nitrous oxide or enflurane-nitrous oxide anaesthesia in operations of long duration

A randomized, prospective, comparative study was performed to evaluate induction characteristics, haemodynamic changes and recovery in 60 ASA I-II patients undergoing mainly gynaecological laparotomies with either propofol or thiopentone-enflurane anaesthesia. The propofol group (n = 30) received 2 mg.kg-1 propofol for induction of anaesthesia followed by propofol infusion. The thiopentone-enflurane group (n = 30) received thiopentone 4 mg.kg-1 for induction followed by enflurane (0.5-2 per cent). All patients received nitrous oxide (66 per cent] in oxygen begun one minute after tracheal intubation, and fentanyl (1.5 micrograms.kg-1) four minutes prior to induction. Other drugs administered during or after anaesthesia were similar among the groups. Haemodynamic measurements were similar between propofol and enflurane groups except after tracheal intubation when the mean arterial pressure was lower in the propofol group (P less than 0.05). The propofol group had significantly less (P less than 0.01) emesis in the recovery room than the enflurane group. The propofol group experienced significantly less (P less than 0.05) dizziness, depression/sadness and hunger than the enflurane group in the postoperative period as assessed with a visual analogue questionnaire. We conclude that propofol provided better outcome than enflurane in terms of these nonvital but annoying outcome measures after relatively long intra-abdominal operations.     

Dreaming and anaesthesia: total i.v. anaesthesia with propofol versus balanced volatile anaesthesia with enflurane.

Sixty consecutive ASA Grades I and II patients scheduled for elective ear, nose and throat surgery were randomly assigned to receive either total i.v. anaesthesia with propofol ('propofol group') or 'balanced technique' with thiopentone induction followed by N2O and enflurane. Patients were asked whether they had experienced dreams immediately after extubation when verbal communication was established, in the recovery room and in the ward on the evening of the day of surgery. Thirteen patients in the propofol group (43%) and three patients in the enflurane group (10%) reported dreaming (P less than 0.05) when asked as soon as verbal communication was established. In the recovery room and in the ward only three patients of the propofol group (10%) and one patient in the enflurane group (3%) remembered that they had been dreaming (NS). To avoid underestimating the frequency of peri-operative dreaming, post-operative interviews should take place as soon as possible after conversing is possible.     

Recovery after General Anaesthesia for Laparoscopy

Recovery after two methods of light general anaesthesia for gynaecological laparoscopy was studied. For this purpose, 30 patients were divided into two equal groups (A and B). The patients in group A were anaesthetized with thiopentone, fentanyl and suxamethonium infusion, while the patients in group B received inhalation anaesthesia with enflurane and suxamethonium infusion. Both groups were normoventilated with nitrous-oxide and oxygen mixture. A battery of recovery tests was applied in the recovery room. The patients who received inhalation anaesthesia with enflurane scored better in the recovery tests, and reached preoperative values after 3 h in the recovery room. Inhalation anaesthesia with enflurane was accepted well by the patients and provided good working conditions for the surgeons. It is suitable for outpatient gynaecological laparoscopy because it ensures rapid recovery.     

Enflurane enhances postischemic functional recovery in the isolated rat heart

Enflurane is a direct myocardial depressant and may act as a myocardial protective agent during ischemia. The authors studied the effects of enflurane on myocardial high-energy phosphates and tolerance to ischemia in the normothermic, isolated rat heart. After isolation and perfusion with Krebs-Henseleit buffer, the hearts were perfused with either buffer (control) or buffer gassed with 2% enflurane for 10 minutes. Thereafter, hearts were made globally ischemic and elapsed times to initiation of ischemic contracture (IC) were determined. ATP and creatine phosphate (CP) were measured at the conclusion of control and enflurane administration and at IC. Ten hearts per group were reperfused with buffer following IC for 20 min; peak pressure and ATP and CP were determined. Administration of 2% enflurane significantly decreased peak pressure by 20% but did not alter baseline high-energy phosphate levels nor did it prolong time to IC. However, enflurane-treated hearts exhibited significantly greater (P less than 0.01) recovery of function as defined by per cent return of peak pressure (67% +/- 3%) when compared with those hearts not treated with enflurane preischemically (44% +/- 5%). Also, enflurane-treated hearts had significantly higher (P less than 0.01) ATP levels at the conclusion of reperfusion than hearts not perfused with enflurane (12.2 +/- .8 mumol/g dry weight vs. 9.0 +/- 0.8 mumol/g dry weight). These findings suggest that enflurane administered prior to an ischemic interval enhances postischemic myocardial recovery.     

Recovery of respiratory ciliary function after depression by inhalation anaesthetic agents: an in vitro study using nasal turbinate explants

We have developed a human tissue preparation suitable for measurement of cilia beat frequency derived from nasal turbinates. Cilia beat frequency of turbinate explants from 11 patients did not change significantly over a 10-day observation period while maintained in an incubator, with mean cilia beat frequency of 13.1 (SEM 0.3) Hz to 14.4 (0.2) Hz (ANOVA for repeated measures, P = 0.168). We have used this preparation to investigate recovery of ciliary function after depression by inhalation anaesthetic agents. Eight or nine turbinate explants were exposed to three times the minimum alveolar concentration (MAC) of halothane, enflurane or isoflurane for a period of 1 h and thereafter to a period of air washout. After exposure to the inhalation agent there was a significant reduction in cilia beat frequency with all three agents: halothane 14.3 (0.4) Hz to 9.5 (0.3) Hz; enflurane 13.7 (0.6) Hz to 10.5 (0.5) Hz;isoflurane 15.9 (0.6) Hz to 10.6 (0.3) Hz. Cilia beat frequency returned to values after air washout that were not significantly different from baseline after 90 min of washout of halothane and 60 min of washout of enflurane and isoflurane (repeated measures ANOVA, unpaired t test; P = 0.01 at 60 min and P = 0.31 at 90 min washout for halothane; P = 0.83 at 60 min washout for enflurane; P = 0.26 at 60 min washout for isoflurane).      

A multicentre trial in spontaneously breathing patients. A comparison of recovery following alfentanil or enflurane

Recovery from anesthesia and the effect of premedication, induction agent and the individual anesthetist on the measure of recovery was assessed in 707 patients scheduled to undergo short surgical procedures. Patients were randomly allocated to receive either alfentanil or enflurane as a supplement to an induction agent, nitrous oxide/oxygen anesthetic technique with or without premedication. Patients who received alfentanil had a faster immediate recovery than those who received enflurane (p less than 0.001). Total anesthetic time was shorter in the alfentanil group (p = 0.02). For 36 of 37 anesthetists recovery was faster in the alfentanil group compared to the enflurane group. Choice of premedication and induction agent had a significant effect on recovery, thiopentone or lorazepam prolonged recovery time in each group. Although the alfentanil group had a higher incidence of apnoea, movement and vomiting (p less than 0.001), the enflurane group had a higher incidence of coughing (p less than 0.001) and shivering (p = 0.004). Overall the anesthetists assessed the alfentanil technique as excellent or good in more patients than the enflurane technique.     

EFFECTS OF ENFLURANE AND ISOFLURANE IN AIR-OXYGEN ON CHANGES IN THERMAL BALANCE DURING AND AFTER SURGERY

The temperatures in the aural canal (core), skeletal muscleand skin surface were measured during anaesthesia and surgeryin 32 healthy females undergoing total abdominal hysterectomyand for 4 h after operation. The patients were allocated randomlyto one of four groups according to the end-tidal concentrationof volatile anaesthetic: 1 MAC isoflurane, 1 MAC enflurane,1.8 MAC isoflurane and 1.8 MAC enflurane. The lungs were ventilatedwith an air-oxygen mixture. Neuromuscular block was producedwith pancuronium. Room temperature and i.v. fluid administrationwere standardized. Aural canal, muscle and mean skin temperaturesdecreased significantly in all groups during surgery (P <0.001). The decrease in core and muscle temperatures, and meanbody heat was significantly greater in the 1.8 MAC groups thanin the 1 MAC groups for both volatile agents (P < 0.001).However, there was a significantly greater decrease in coretemperature and mean body heat in the isoflurane compared withthe enflurane group (P < 0.026). Body temperature returnedto preoperative values during the recovery period. There wasa significantly greater rate of rewarming during the first 1h of recovery in the 1.8 MAC groups compared with the 1 MACequivalent (P < 0.001), and this was independent of the volatileagent used. The present results are compared with those reportedpreviously in which nitrous oxide was added to the volatileagents. The decrease in body temperature depends upon the concentrationof vapour used. However, it appears that isoflurane, withoutnitrous oxide, caused greater loss of body heat than enflurane.     

Left ventricular oxygen tensions in dogs during coronary vasodilation by enflurane, isoflurane and dipyridamole

The purpose of this study was to investigate the effects of the anesthetics enflurane and isoflurane and of the coronary vasodilator dipyridamole on myocardial oxygen balance and myocardial tissue oxygen tensions. The studies were performed in 24 open-chest dogs during basal anesthesia with a narcotic. Myocardial blood flow (MBF) was measured using radioactive microspheres, myocardial surface tissue PO2 by means of a platinum multiwire surface electrode. One control group and three experimental groups were studied: enflurane (1.1 vol%), isoflurane (0.7 vol%, both end-tidal concentrations), and dipyridamole (0.4 mg/kg). Mean arterial pressure significantly decreased to an average of 70 mm Hg in all three experimental groups. Although MBF was unchanged during enflurane (-18%) and isoflurane (+20%), it increased during dipyridamole (+304% p less than 0.05 vs baseline and control, enflurane, and isoflurane groups). Myocardial oxygen consumption decreased significantly during enflurane and isoflurane but remained unchanged during dipyridamole. Thus, the ratio between myocardial oxygen delivery and consumption increased 6% with enflurane (p less than 0.05 vs baseline), 47% with isoflurane (p less than 0.05 vs baseline and control group) and 280% with dipyridamole (p less than 0.05 vs baseline and control, enflurane, and isoflurane groups). Coronary venous PO2 remained unchanged during enflurane but increased significantly during isoflurane and dipyridamole. Left ventricular surface tissue PO2 was unchanged in enflurane and isoflurane animals and decreased slightly, yet significantly, during dipyridamole. All variables remained unchanged in the control group. Thus, isoflurane and dipyridamole interfered with MBF autoregulation and increased myocardial oxygen delivery out of proportion to myocardial demands.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of recovery times of isoflurane and enflurane as a sole anesthetic agent for outpatient oral surgery

Patients' abilities to complete the Trieger modification of the Bender Motor Gestalt Test as an indicator of recovery time were compared following outpatient general anesthesia, using either enflurane or isoflurane on 100 patients who had their third molars removed. The time required for patients who received enflurane to satisfactorily complete the test averaged 32.7 minutes, compared with 34.6 minutes for patients who received isoflurane. Statistical analysis indicated that there was no significant difference in recovery time in this particular setting between enflurane and isoflurane.     

Vomiting, retching, headache and restlessness after halothane-, isoflurane- and enflurane-based anaesthesia: An analysis of pooled data following ear, nose, throat and eye surgery

Background: Isoflurane has exceeded halothane and enflurane in usage. A literature search, however, revealed no data comparing the effects on emesis, headache and restlessness of these three agents.
Methods: With hospital ethics committee approval and patient consent, a prospective, randomised, double-blind study of 556 patients undergoing ENT and eye surgery was undertaken to evaluate the effects of halothane, isoflurane and enflurane on vomiting, retching, headache and restlessness until 24 h after anaesthesia. Balanced general anaesthesia was administered comprising benzodiazepine premedication, induction with thiopentone-atracurium-morphine (ENT patients) or fentanyl (eye patients), controlled ventilation and maintenance with either halothane 0.4–0.6 vol% (n = 186), isoflurane 0.6–0.8 vol% (n = 184) or enflurane 0.8–1 vol% (n=186) in nitrous oxide 67% and oxygen.
Results: The three study groups were comparable, and comprised comparable subgroups having ear, nose, throat, intraocular and non-intraocular surgery. During early recovery from anaesthesia, the respective requirements for halothane, isoflurane and enflurane for analgesia (7%, 9% and 10%), frequency of emesis (6%, 8% and 8%), antiemetic requirements (1%, 1% and 2%), restlessness-pain scores and time spent in the recovery ward (27 SD 10, 31 SD 12 and 26 SD 9 min) were similar. During the ensuing 24-h postoperative period, patients who had isoflurane experienced emesis less often than those who had halothane (36% vs 46%, P <0.025) but did so with similar frequency to those who had enflurane (46% vs 41%). Antiemetic requirements were least in those given isoflurane (isoflurane 12%, halothane and enflurane 23% each, P <0.005), but headache and analgesic requirements were similar.
Conclusion: Isoflurane induces less postoperative emesis than halothane, but headache is similarly frequent after anaesthesia with any of these agents.     

ENFLURANE IN OUTPATIENT PAEDIATRIC DENTAL ANAESTHESIA: A comparison with halothane

Enflurane and halothane were compared as volatile supplementsto nitrous oxide anaesthesia for 80 children presenting foroutpatient dental extractions. Induction and maintenance ofanaesthesia were comparable and satisfactory with both agents,but recovery of consciousness was significantly quicker followingenfiurane anaesthesia. Full recovery from either enflurane orhalothane was of similar duration. Present address: Wycombe General Hospital, High Wycombe, Bucks     

A comparison of anaesthesia using remifentanil combined with either isoflurane, enflurane or propofol in patients undergoing gynaecological laparoscopy, varicose vein or arthroscopic surgery

BACKGROUND: Anaesthesia comprising remifentanil plus isoflurane, enflurane or propofol was randomly evaluated in 285, 285 and 284 patients, respectively, undergoing short-procedure surgery. METHODS: Anaesthesia was induced with propofol (0.5 mg x kg(-1) and 10 mg x 10 s(-1)), and a remifentanil bolus (1 microg x kg(-1)) and infusion at 0.5 microg x g(-1) x min(-1). Five minutes after intubation, remifentanil infusion was halved and 0.5 MAC of isoflurane or enflurane, or propofol at 100 microg x kg(-1) x min(-1) were started and titrated for maintenance. RESULTS: Patient demography and anaesthesia duration were similar between the groups. Surgery was performed as daycases (52%) or inpatients (48%). The median times (5-7 min) to extubation and postoperative recovery were similar between the groups. Responses to tracheal intubation (15% vs 8%) and skin incision (13% vs 7%) were significantly greater in the total intravenous anaesthesia (TIVA) group (P<0.05). Fewer patients given remifentanil and isoflurane (21%) or enflurane (19%) experienced > or =1 intraoperative stress response compared to the TIVA group (28%) (P<0.05). Median times to qualification for and actual recovery room discharge were 0.5-0.6 h and 1.1-1.2 h, respectively. The most common remifentanil-related symptoms were muscle rigidity (6-7%) at induction, hypotension (3-5%) and bradycardia (1-4%) intraoperatively and, shivering (6-7%), nausea and vomiting postoperatively. Nausea (7%) and vomiting (3%) were significantly lower with TIVA compared with inhaled anaesthetic groups (14-15% and 6-8%, respectively; P<0.05). CONCLUSION: Anaesthesia combining remifentanil with volatile hypnotics or TIVA with propofol was effective and well tolerated. Times of extubation, postanaesthesia recovery and recovery room discharge were rapid, consistent and similar for all three regimens.     

MAC-AWAKE OF ISOFLURANE, ENFLURANE AND HALOTHANE EVALUATED BY SLOW AND FAST ALVEOLAR WASHOUT

End-tidal anaesthetic concentrations at first eye opening inresponse to a verbal command during recovery from anaesthesia(MAC-awake), were measured for isoflurane (n = 16), enflurane(n = 16) and halothane (n = 14). MAC-awake was measured duringeither slow or fast alveolar washout. Slow washout was obtainedby decreasing anaesthetic concentrations in predetermined stepsof 15min, assuming equilibration between brain and alveolarpartial pressures. Fast alveolar washout was obtained by discontinuationof the inhalation anaesthetic, which had been maintained at1 MAC for at least 15 min. Mean MAC-awake obtained with slowalveolar washout was similar for isoflurane (0.25 (SD 0.03)MAC), and enflurane (0.27 (0.04) MAC) and significantly greaterthan values obtained by fast alveolar washout (isoflurane: 0.19(0.03) MAC; enflurane: 0.20 (0.03) MAC). The MAC-awake of isofluraneand enflurane was significantly less than that of halothane,which was 0.59 (0.10) MAC as evaluated by the slow and 0.50(0.05) MAC as evaluated by the fast alveolar washout method.Recovery time from anaesthesia with fast alveolar washout was8.8 (4.0) min for halothane, which was not different from isoflurane(15 (2.5) min), but significantly shorter than for enflurane(22 (10) min), reflecting differences in the anaesthetic concentrationgradient between MAC and MAC-awake values. These data do notsupport the hypothesis of a uniform ratio between MAC and MAC-awakevalues.