A comparison of midazolam co-induction with propofol predosing for induction of anaesthesia

In a double-blind, placebo-controlled study of 90 ASA 1 and 2 patients scheduled for elective surgery we compared the effect of pre-administering midazolam 2 mg or propofol 30 mg on the dose of propofol subsequently required to induce anaesthesia. Using loss of response to verbal command and tolerance to placement of a facemask as end-points, the dose of propofol required to induce anaesthesia was significantly smaller in the patients given propofol (1.87 mg.kg-1) or midazolam (1.71 mg.kg-1) when compared to the control group (2.38 mg.kg-1). Although the decrease in blood pressure following induction was no difference between the two study groups and the decrease was felt not to be of clinical significance in this group of patients. As propofol is presented ' ... for use in a single patient only' and the technique of predosing with propofol allowed induction of all patients with less than 200 mg (a single ampoule), we question on a cost basis whether midazolam co-induction is necessary to reduce propofol induction doses.     

Ambulatory anesthesia and induced abortion. Comparative study of propofol-alfentanyl and ketamine-midazolam combinations

The use of propofol alone or with alfentanil in the day-case anaesthesia for abortion was compared with that of ketamine with midazolam. Two hundred young women were assigned to two successive series of two groups each. The four groups were: group 1 (2 mg . kg-1 propofol only); group II (0.5 mg . kg-1 ketamine with 0.25 mg . kg-1 midazolam); group III (2 mg . kg-1 propofol with 4 micrograms . kg-1 alfentanil); group IV (1 mg . kg-1 ketamine with 0.1 mg . kg-1 midazolam). All the patients were premedicated one hour before anaesthesia with 0.25 mg . kg-1 midazolam orally. All the patients were asleep at the end of the propofol injection (60 s), and 10 to 15 s later for the ketamine-midazolam groups. The haemodynamic parameters did not vary much during induction with ketamine-midazolam. In the propofol groups, the heart rate remained steady, with an 8 to 12% fall in blood pressure. A fall of the mandible was seen in 40 and 84% of the patients in the propofol groups, with a short apnoea in 32 and 48% of these same patients. Clinical recovery was very quick, less than 12 min for all groups. The four psychomotor and sensory tests were carried out at the 30th min by 95% of the patients in the propofol groups, whereas only 50% of those in the ketamine-midazolam groups did so. Speed and quality were significantly better in the propofol groups. The most frequent adverse effect of propofol was pain during injection in 32 and 14% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of propofol, propofol-nitrous oxide and midazolam on cortical somatosensory evoked potentials during sufentanil anaesthesia for major spinal surgery

Recording of cortical somatosensory evoked potentials (CSEP) enables monitoring of spinal cord function. We studied the effects of propofol, propofol-nitrous oxide or midazolam during sufentanil anaesthesia on CSEP monitoring during major spinal surgery. Thirty patients with normal preoperative CSEP were allocated randomly to one of the following anaesthesia regimens: propofol (2.5 mg kg-1 followed by 10-6 mg kg-1 h-1) with or without nitrous oxide, or midazolam (0.3 mg kg-1 followed by 0.15 mg kg-1 h-1) combined with sufentanil 0.5 microgram kg- 1 h-1 in the propofol and midazolam groups, or 0.25 microgram kg-1 h-1 in the propofol-nitrous oxide group. CSEP were elicited by alternate right and left tibial posterior nerve stimulation and recorded before and after induction (15 min, 1, 2 and 3 h), and during skin closure. CSEP latencies were not significantly modified in the three groups. CSEP amplitude decreased significantly in the propofol-nitrous oxide group (from mean 2.0 (SEM 0.3) to 0.6 (0.1) microV; P < 0.05) but not in the propofol (from 1.8 (0.6) to 2.2 (0.3) microV) or midazolam (1.7 (0.5) to 1.6 (0.5) microV) groups. The time to the first postoperative voluntary motor response (recovery) delay was significantly greater in the midazolam group (115 (19) min) compared with the propofol and propofol-nitrous oxide groups (43 (8) and 41 (3) min, respectively). Consequently, the use of propofol without nitrous oxide can be recommended during spinal surgery when CSEP monitoring is required.      

Effects of speed of injection on anesthesia induction with propofol and fentanyl]

We examined the effects of injection rate of propofol on injection pain and postinduction hypotension and bradycardia when fentanyl was administrated before propofol. Fifty-five patients premedicated with midazolam and atropine were randomly allocated to two groups. Three minutes after administration of fentanyl 100 micrograms, propofol 1.5 mg.kg-1 was injected to a forearm vein at a rate of 800 ml.hr-1 in Group FS or 1 ml.s-1 in Group FR. Anesthesia was maintained with 67% nitrous oxide in oxygen and supplemental propofol infusion. The incidence and severity of pain on injection were not influenced with injection speed. The rapid rate of injection significantly shortened the induction time. The decrease in systolic and diastolic blood pressures and heart rate after induction were not affected by injection speed. In conclusion, rapid injection of propofol after fentanyl was effective to shorten the induction time without increasing the postinduction hypotension and bradycardia.     

Target-controlled propofol requirements at induction of anaesthesia: effect of remifentanil and midazolam

BACKGROUND AND OBJECTIVE: Target-controlled infusions of anaesthetic agents have become increasingly available. They can involve the use of propofol in combination with an opioid or a benzodiazepine. The effect site concentration of propofol infusions has been advocated as a method of estimating drug distribution. We investigated the influence of co-induction with remifentanil and midazolam on effect site propofol requirements at induction of anaesthesia using target-controlled infusions. METHODS: Sixty-six consenting adult patients were randomly allocated to three treatment groups. Each group received induction of anaesthesia with a different total intravenous technique. One group was induced with target-controlled propofol alone; another received target-controlled propofol and target-controlled remifentanil (3 ng mL-1); and the last received midazolam (0.03 mg kg-1), target-controlled remifentanil (3 ng mL-1) and target-controlled propofol. Computer simulation was used to calculate effect site concentrations. We recorded propofol dose and effect site concentration at loss of verbal response. RESULTS: The effect site concentration (Ce50) of propofol alone was 2.19 micrograms mL-1. This was reduced to 1.55 micrograms mL-1 during co-induction with remifentanil and further reduced to 0.64 microgram mL-1 with midazolam premedication (P < 0.001; ANOVA). CONCLUSIONS: We conclude that co-induction with remifentanil alone or with midazolam can be used to reduce propofol doses at induction of anaesthesia using target-controlled infusions. We believe that using effect site concentration may prove a useful tool in routine clinical practice.     

Recovery and discharge of patients after long propofol infusion vs isoflurane anaesthesia for ambulatory surgery

Fifty unpremedicated patients scheduled for outpatient restorative dentistry and/or oral surgery lasting 2 to 4 h were anaesthetized with either propofol infusion or isoflurane inhalation. Before induction of anaesthesia with propofol (2.5 mg.kg-1), all patients were given 75 mg of diclofenac and 0.01 mg.kg-1 vecuronium intravenously. Intubation was facilitated with suxamethonium (1.5 mg.kg-1) and anaesthesia was maintained in random order either with propofol infusion (12 mg.kg-1.h-1 for the first 20 min, 9 mg.kg-1.h-1 for the next 20 min, and 6 mg.kg-1.h-1 for the rest of the anaesthesia) or with isoflurane (inspired concentration 1-2.5%), both with nitrous oxide and oxygen (30%). The patients breathed spontaneously using a non-rebreathing circuit. Patients given propofol infusion became re-orientated faster (11.0 +/- 5.5 min vs. 16.5 +/- 7.5 min; P less than 0.01) and at 30 min walked along a straight line better (P less than 0.01). At 60 min, none of the propofol patients displayed an unsteady gait, whereas 11 of the 25 isoflurane patients did (P less than 0.001). None of the patients receiving propofol had emesis at the clinic, compared with 10 of the 25 patients receiving isoflurane (P less than 0.001). The overall incidence of emesis was 2 of 25 and 14 of 25 in the propofol and isoflurane groups, respectively (P less than 0.01). Patients receiving propofol were discharged home earlier than patients receiving isoflurane (80 +/- 14 min and 102 +/- 32 min, respectively; P less than 0.01). It is concluded that propofol allows early discharge of patients, even after long anaesthesias.     

A comparison between midazolam co-induction and propofol predosing for the induction of anaesthesia in the elderly

In a prospective, double-blind, randomised, placebo-controlled trial, we have compared the effects of midazolam co-induction with propofol predosing on the induction dose requirements of propofol in elderly patients. We enrolled 60 patients aged > 70 years, attending for urological surgery. The patients were allocated randomly to one of three groups, to receive either midazolam 0.02 mg.kg(-1), propofol 0.25 mg.kg(-1), or normal saline 2 ml (placebo) 2 min prior to induction of anaesthesia using propofol 1% infusion at 300 ml.h(-1). The propofol dose requirements for induction were recorded for two end-points (loss of verbal contact and insertion of an oropharyngeal airway). Cardiovascular parameters were recorded at 1-min intervals for each patient until induction was complete. The midazolam group showed a significant reduction in propofol dose requirements for induction (p = 0.05) compared to the placebo group. The propofol group did not show a significant dose reduction compared to placebo. There were no demonstrable differences in terms of improved cardiovascular stability between groups. We conclude that propofol predosing does not significantly reduce the induction dose of propofol required in the elderly, and there were no cardiovascular benefits to either midazolam co-induction or propofol predosing in the elderly.     

Midazolam/propofol but not propofol alone reversibly depress the swallowing reflex

General anaesthetics depress swallowing and this is a reason to delay oral intake after general anaesthesia. The swallowing reflex was studied 2 h after general anaesthesia for patients undergoing colonoscopy. Forty–one patients were anaesthetized with midazolam 75 μgkg^-1 followed by a continuous infusion of propofol and 39 patients with propofol 1.5 mgkg^-1 bolus followed by an infusion. Swallowing reflex was measured by electromyography 2 h after induction of anaesthesia, before and 5 min after the administration of flumazenil (0.2 mg) or placebo. Two h after anaesthesia, the state of consciousness was almost normal in all patients and did not change after flumazenil. At two hours, the latency times for the swallowing reflex in patients treated with propofol alone were of 1.4 ± 0.4 s and were significantly shorter ( P < 0.05) than the value of 1.9 ± 0.8 s observed in patients who received midazolam with propofol. In the latter group the latency time of the swallowing reflex was significantly reduced following the administration of flumazenil but not placebo. In patients who received propofol without midazolam, the administration of flumazenil or placebo was not associated with significant changes in the latency times. There were also no significant differences in the latency times in the subgroup that received midazolam followed by flumazenil and the propofol alone groups that did or did not receive flumazenil. These results suggest that midazolam still exerts a depressive effect on the swallowing reflex 2 h after its administration despite the recovery of normal consciousness.     

Small dose midazolam or droperidol reduces the hypnotic dose of propofol at the induction of anaesthesia

We investigated the effect of a small dose of midazolam, ketamine, droperidol or lidocaine on the propofol dose required for hypnosis during induction of general anaesthesia. These drugs were randomly administered to 100 patients about to undergo scheduled surgery. Propofol was then infused at a rate of 250 microg kg-1 min-1 and the hypnotic dose to produce hypnosis was evaluated. Midazolam (20 microg kg-1) and droperidol (20 microg kg-1) significantly reduced the mean hypnotic dose of propofol (mean) S.D.) compared with the placebo (43.7 +/- 17.8 mg, 61.9 +/- 10.6 mg and 72.5 +/- 27.7 mg after pretreatment with midazolam, droperidol and placebo, respectively), whereas ketamine (0.1 mg kg-1) and lidocaine (1 mg kg-1) did not significantly affect the hypnotic dose of propofol (63. 1 +/- 25.6 mg and 65.1 +/- 24.8 mg, respectively). Only midazolam when compared with saline administration, (176 +/- 66 s and 298 +/- 126 s, respectively), shortened the time to achieve hypnosis. The changes in blood pressure (non-invasive) and heart rate were not significantly different in all groups during the induction of anaesthesia and oro-tracheal intubation. These results raise the possibility that new combinations of central nervous system drugs, such as droperidol and propofol, have a potential to reduce the dose of intravenous anaesthetics, including propofol, that produce hypnosis without significant adverse effects.     

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.     

Total intravenous anaesthesia with propofol,alfentanil, and oxygen-air: three different dosage schemes

Three different dosage schemes of propofol infusions combined with a fixed-rate alfentanil infusion were investigated in total intravenous anaesthesia. In 30 premedicated patients, divided at random into three groups, anaesthesia was induced with propofol 2 mg.kg-1 immediately followed by an alfentanil infusion 10 micrograms.kg-1.min-1 as a loading dose which was decreased after ten minutes to a maintenance dose of 1 microgram.kg-1.min-1. Vecuronium bromide 0.1 mg.kg-1 was used as the muscle relaxant. After induction of anaesthesia a propofol infusion 2 mg.kg-1.hr-1 was started in group A, 3 mg.kg-1.hr-1 in group B and 4 mg.kg-1 hr-1 in group C. At signs of light anaesthesia supplementary bolus doses of 20 mg propofol and 1 mg alfentanil were given. The patients' lungs were ventilated with air-oxygen (FIO2 0.35). The mean systolic and diastolic blood pressures showed no statistical significant differences between the three groups. A significant (P less than 0.01) decrease of the mean systolic and diastolic blood pressures was present after induction of anaesthesia and tracheal intubation. Recovery was uneventful in all but one patient, who had ventilatory depression that responded to naloxone (0.2 mg IV). Awareness did not occur in any patient. The only difference between the three groups was the higher number of supplementary bolus doses of propofol and alfentanil needed in group A (P less than 0.01). In total intravenous anaesthesia propofol 3 and 4 mg.kg-1.hr-1 as a maintenance dose combined with a two-step fixed-rate alfentanil infusion provided smooth anaesthesia and uneventful rapid recovery.     

Continuous propofol infusion versus enflurane in children operated on for strabismus. Comparison of the quality of anesthesia and recovery conditions

In children, the use of a continuous infusion of propofol has not yet been reported. A study was therefore designed to compare the characteristics of anaesthesia and recovery when either propofol or enflurance was used as the main anaesthetic agent. All 42 children (14 girls, 28 boys), ASA I and scheduled for corrective squint surgery under general anaesthesia, received 350 micrograms.kg-1 midazolam and 40 micrograms.kg-1 atropine intrarectally 20 min before induction, which was carried out with 3 mg.kg-1 propofol intravenously in 20 s. The patients were then randomly assigned to two groups, according to the drug used for maintenance: group P (n = 21) received a continuous intravenous infusion of propofol, 18 mg.kg-1.h-1 for the first 30 min and 15 mg.kg-1.h-1 thereafter; group E (n = 21) received 2.5%, then, after 30 min, 2% enflurane. Both groups were given 15 micrograms.kg-1 dextromoramide and 0.09 mg.kg-1 vecuronium. During anaesthesia, the following parameters were monitored: systolic (Pasys), diastolic (Padia) and mean arterial (Pa) pressures, heart rate (fc), the presence or not of an oculocardiac reflex with or without a 20% fall in fc which responded to 10-15 micrograms.kg-1 atropine, the appearance of a cardiac dysrhythmia, duration of anaesthesia and the delay before extubation. Recovery was assessed 1, 2, 4 and 6 h postoperatively by using both clinical and psychomotor criteria, the latter being adapted to children having one or both eyes occluded.(ABSTRACT TRUNCATED AT 250 WORDS)     

A combination of fentanyl-midazolam-propofol provides better intubating conditions than fentanyl-lignocaine-propofol in the absence of neuromuscular blocking agents

BACKGROUND: The use of propofol and adjuvants such as opioids, benzodiazepines and local anaesthetic agents, may provide adequate conditions for tracheal intubation without the need for neuromuscular blocking agents. In this randomized, double-blind study, intubating conditions after induction of anaesthesia with propofol, midazolam and fentanyl were compared with those after propofol, lignocaine and fentanyl. METHODS: In 80 ASA I/II adult patients undergoing elective gynaecological surgery, intubating conditions were compared after induction of anaesthesia with a fentanyl 2 microg/kg, midazolam 0.03 mg/kg, propofol 2.5 mg/kg combination (group FMP) vs. a fentanyl 2 microg/kg, lignocaine 1.5 mg/kg, propofol 2.5 mg/kg combination (group FLP). Intubating conditions were assessed using a qualitative scoring system. RESULTS: Intubation was successful in all patients in group FMP and in 87.5% of patients in group FLP; (P= 0.021). Overall, intubating conditions were clinically acceptable in 77.5% and 55% of patients in group FMP and group FLP, respectively (P= 0.033). CONCLUSION: We conclude that the fentanyl, midazolam, propofol combination more reliably provides acceptable conditions for intubation than the fentanyl, lignocaine, propofol combination. Intubation was successful in all patients receiving the fentanyl, midazolam, propofol combination.     

Cerebrospinal fluid concentrations of propofol during anaesthesia in humans

The concentration of propofol in and surrounding the human brain during propofol anaesthesia is unknown. We measured simultaneously the concentration of propofol in cerebrospinal fluid (CSF) from an indwelling intraventricular catheter and the concentration in arterial blood in five neurosurgical patients before, during induction (at 2.5 and 5 min) and during a maintenance propofol infusion (at 15 and 30 min). After induction of anaesthesia with propofol 2 mg kg-1, anaesthesia was maintained with an infusion of 8 mg kg-1 h-1 for 15 min and then reduced to 6 mg kg-1 h-1. The plasma concentration of propofol increased rapidly during induction and reached a plateau concentration of mean 2.24 (SD 0.66) micrograms ml-1 after 5 min. The concentration of propofol in CSF showed a slower increase during induction and remained almost constant at 35.5 (19.6) ng ml-1 at 15-30 min after induction. The CSF concentration of propofol that we measured was 1.6% of the plasma concentration and consistent with the high protein binding of the drug in plasma.      

Effective time to satisfactory intubation conditions after administration of rocuronium in adults. Comparison of propofol and thiopentone for rapid sequence induction of anaesthesia

We determined the effective time to satisfactory intubation conditions after the administration of rocuronium 0.6 mg.kg-1 to 120 unpremedicated adult patients anaesthetised with propofol 2.5 mg.kg-1 or thiopentone 5 mg.kg-1. Intubation conditions were assessed in 10 subgroups of 12 patients at 30, 40, 50, 60 and 70 s. The effective times to satisfactory intubation conditions in 50 and 90% of patients were obtained by the method of maximum likelihood after log time-probit response transformations. Intubation conditions after induction of anaesthesia with propofol were satisfactory in 5/12 patients at 30 s, 7/12 at 40 s, 10/12 at 50 s, 11/12 at 60 s and 11/12 at 70 s compared with 1/12 patients at 30 s, 2/12 at 40 s, 5/12 at 50 s, 7/12 at 60 s and 8/12 at 70 s after induction with thiopentone. The effective times to satisfactory intubation conditions in 50% and 90% (95% confidence intervals) of patients after rocuronium 0.6 mg.kg-1 were 34 (26-40) s and 61 (50-81) s in patients given propofol compared with 57 (48-69) s and 101 (79-167) s in patients given thiopentone. We conclude that rocuronium 0.6 mg.kg-1 may be a suitable alternative to suxamethonium during rapid sequence induction of anaesthesia with propofol in situations where suxamethonium is contraindicated.     

Anesthesia for arthroscopy of the knee: propofol versus thiopental and halothane

Sixty ASA I or II patients, who underwent general anaesthesia for arthroscopy of the knee, were separated into two groups. Induction was performed either with thiopentone 7 mg . kg-1 (group I) or with propofol 2.5 mg . kg-1 (group II). All patients were intubated and ventilated. Dextromoramide was used as analgesic. Maintenance of anaesthesia was obtained with halothane inhalation (group I) or by continuous automatic injection of propofol at a dose of 9 mg . kg-1 . h-1 (group II). Induction and maintenance were satisfactory in both groups. Pulse rate was stable at induction and intubation for the propofol group, whereas it increased at both stages of anaesthesia with thiopentone; it fell moderately in both groups afterwards. Systolic and diastolic blood pressures dropped more in the propofol group after induction, with a maximum decrease of 20%. Recovery was significantly more rapid and comfortable with propofol than with thiopentone.     

Premedication with intramuscular midazolam: effect on induction time with intravenous midazolam compared to intravenous thiopentone or ketamine

Our study sought to determine whether premedication with intramuscular midazolam would decrease the time to induction of anaesthesia with intravenous midazolam, and if so whether induction of anaesthesia would be as rapid as with thiopentone or ketamine, intravenously. Eight-nine patients, ASA physical status I or II, received midazolam 0.2 mg X kg-1, thiopentone 3.0 mg X kg-1, or ketamine 2.0 mg X kg-1 intravenously 60-90 min after intramuscular injection of either midazolam 0.07 mg X kg-1 or matching placebo. Time to induction of anaesthesia or the dose required to induce anaesthesia with intravenous midazolam was not decreased by midazolam premedication. Both with or without premedication, midazolam induction time was longer than with thiopentone or ketamine. Midazolam induction was associated with a lower incidence of blood pressure increase than with ketamine induction, and a lower incidence of apnea than that with either thiopentone or ketamine.     

Comparison of midazolam and propofol in combination with alfentanil for total intravenous anesthesia

Hemodynamic function during induction of anesthesia, the alfentanil and naloxone requirements, and the speed of recovery from total intravenous anesthesia with alfentanil/midazolam (group M, n = 10) or alfentanil/propofol (group P, n = 10) were compared in patients undergoing lower limb surgery. Twenty patients were randomly assigned to receive either 2 mg/kg propofol in 5 min followed by 9 mg.kg-1.h-1 for 30 min and 4.5 mg.kg-1.h-1 until skin closure, or 0.42 mg/kg midazolam in 5 min followed by 0.125 mg.kg-1.h-1 until skin closure. Simultaneously, a variable-rate infusion of alfentanil was given. Patients were ventilated with 30% oxygen in air. In both groups blood pressure and heart rate decreased significantly (P less than 0.02) and to a similar extent during induction. The total dose of alfentanil was similar in both groups. No patient in group P and nine patients in group M needed naloxone (average dose 130 +/- 70 micrograms, P less than 0.001). Recovery, as judged by psychomotor tests (90% score was reached at 1 h in the P group and at about 4 h in the M group, P less than 0.001), sedative scores, and orientation in time and place, was shorter in group P than in group M. The conclusion is reached that propofol is superior to midazolam in total intravenous anesthesia with alfentanil.     

Midazolam-flumazenil vs. propofol in ambulatory ENT endoscopic procedures.

Two total intravenous anaesthesia techniques were compared in an open study of 80 ambulatory patients undergoing ENT endoscopic procedures randomly assigned to two groups: Group I midazolam-flumazenil n = 40, Group II propofol n = 40. The mean doses including induction were 0.75 +/- 0.31 mg kg-1 h-1 for midazolam and 171 +/- 64 micrograms kg-1 min-1 for propofol for 46.3 +/- 17.7 min and 50.3 +/- 24.8 min respectively. At the end of the procedure flumazenil 8.1 +/- 1.9 micrograms kg-1 was administered to Group I patients followed by a flumazenil continuous infusion at a minimal arousal rate (MAR) of 0.24 +/- 0.1 micrograms kg-1 min-1, and propofol discontinued in Group II patients. Baseline mean arterial pressure (MAP) and heart rate (HR) were similar in both groups and remained so during the procedure and recovery. In patients with cardiovascular disease, large variations (greater than or equal to 40% of baseline values) occurred more frequently in the propofol group whereas large variations in patients with no cardiovascular disease occurred more frequently in the midazolam group (P less than 0.05). Early recovery was more rapid after midazolam (P less than 0.05) whereas late criteria for recovery (maze and ambulation tests) were met more rapidly after propofol (P less than 0.05). It is concluded that with the midazolam-flumazenil sequence, early recovery is faster and haemodynamic stability better maintained in poor cardiovascular risk patients, whereas with propofol, street-fitness is more rapidly obtained, and haemodynamic stability better maintained in good risk patients.     

Randomized comparison of recovery after propofol-nitrous oxide versus thiopentone-isoflurane-nitrous oxide anaesthesia in patients undergoing ambulatory surgery

A randomized, prospective study was performed to compare recovery characteristics in 41 ASA physical status I-II patients scheduled for ambulatory surgery with either propofol or thiopentone-isoflurane anaesthesia. Particular attention was focused on the recovery time needed to meet discharge criteria. The propofol group received propofol 2 mg.kg-1 for induction followed by propofol infusion (6-9 mg.kg-1.h-1) 1 min after intubation. The thiopentone-isoflurane group received thiopentone 4 mg.kg-1 for induction followed by isoflurane (0.5-2%) 1 min after endotracheal intubation. Other drugs administered during or after anaesthesia were similar between the groups. The propofol group had significantly (P less than 0.05) faster clinical recovery than the isoflurane group with respect to times to response to commands, eye opening, orientation, ability to stand and void, tolerance to oral fluids, "home-readiness", and recovery of perceptual speed. Patients in the propofol group had significantly less (P less than or equal to 0.05) emesis than the patients given isoflurane. We conclude that in patients undergoing ambulatory surgery propofol infusion is preferable to thiopentone-isoflurane anaesthesia, because it may allow faster discharge home.