The effect of anaesthetic agents on induction, recovery and patient preferences in adult day case surgery: a 7-day follow-up randomized controlled trial.

BACKGROUND AND OBJECTIVE: To compare induction, pre- and post-discharge recovery characteristics and patient preferences between four anaesthetic regimens in adult day-surgery. METHODS: Randomized controlled trial. In all, 1158 adults assigned to: propofol induction and maintenance, propofol induction with isoflurane/N2O, or sevoflurane/N2O maintenance, or sevoflurane/N2O alone. We prospectively recorded induction and pre-discharge recovery characteristics, collected 7-day post-discharge recovery characteristics using patient diaries and patient preferences by telephone follow-up. RESULTS: Recruitment rate was 73%--of the 425 refusals, 226 were not willing to risk a volatile induction. During induction, excitatory movements and breath holding were more common with sevoflurane only (P < 0.01). Injection pain and hiccup were more common with propofol induction (P < 0.01). In the recovery room and the postoperative ward, both nausea and vomiting were more common with sevoflurane only (P < 0.01). This difference disappeared within 48 h. There was no difference between groups in the mental state on awakening, recovery time, time to discharge or overnight admissions; then was also no difference in pain between the four groups for each of the seven postoperative days (P < 0.01), nor any differences in concentration or forgetfulness. Patients took 6.5 days (95% CI: 6.0-7.0, n = 693) to resume normal activities. Patients who received sevoflurane only were more likely to recall an unpleasant induction and least likely to want the same induction method again (P < 0.01). CONCLUSION: Differences in outcome between the four regimens are transient; sevoflurane is not an ideal sole agent for adult day case anaesthesia and, in this setting, patients base their preferences for future anaesthetics on the method of induction.

Clinical and economic choices in anaesthesia for day surgery: a prospective randomised controlled trial.

We compared the cost-effectiveness of general anaesthetic agents in adult and paediatric day surgery populations. We randomly assigned 1063 adult and 322 paediatric elective patients to one of four (adult) or two (paediatric) anaesthesia groups. Total costs were calculated from individual patient resource use to 7 days post discharge. Incremental cost-effectiveness ratios were expressed as cost per episode of postoperative nausea and vomiting (PONV) avoided. In adults, variable secondary care costs were higher for propofol induction and propofol maintenance (propofol/propofol; p < 0.01) than other groups and lower in propofol induction and isoflurane maintenance (propofol/isoflurane; p < 0.01). In both studies, predischarge PONV was higher if sevoflurane/sevoflurane (p < 0.01) was used compared with use of propofol for induction. In both studies, there was no difference in postdischarge outcomes at Day 7. Sevoflurane/sevoflurane was more costly with higher PONV rates in both studies. In adults, the cost per extra episode of PONV avoided was pound 296 (propofol/propofol vs. propofol/ sevoflurane) and pound 333 (propofol/sevoflurane vs. propofol/isoflurane).

Anaesthesia for day case surgery: a survey of adult clinical practice in the UK.

BACKGROUND AND OBJECTIVE: In October 2000, we conducted a national postal survey of consultant day case anaesthetists in the UK to explore the range and variation in the practice of anaesthetizing a patient for day case surgery (paediatrics, urology and orthopaedics). The survey was carried out as part of a larger study that comprised a major two-centre randomized controlled trial designed to investigate the costs and outcome of several anaesthetic techniques during day care surgery in paediatric and adult patients (cost-effectiveness study of anaesthesia in day case surgery). We report the findings of this national survey of adult urology and orthopaedic day case anaesthetic practice in the UK. METHODS: The survey used a structured postal questionnaire and collected data on the duration of the surgical procedure; the use of premedication; the anaesthetic agents used for induction and maintenance; the fresh gas flows used for anaesthesia; the use of antiemetics; and the administration of local anaesthesia and analgesia. RESULTS: The overall response rate for the survey was 74% (63% for urology, 67% for orthopaedics). The survey indicated the following practice in adult urology and adult orthopaedic day case surgery: 6 and 12% used premedication; propofol was the preferred induction agent (96 and 97%) and isoflurane the preferred maintenance agent (56 and 58%); 32 and 41% used prophylactic antiemetics; 86 and 93% used a laryngeal mask. CONCLUSIONS: This survey identifies the variation in current clinical practice in adult day surgery anaesthesia in the UK and discusses this variation in the context of current published evidence.

Anaesthetic agents in adult day case surgery.

This study reports a review of all comparative published studies of adult day case anaesthesia in the English language up to December 2000. Ten databases were searched using appropriate keywords and data were extracted in a standardized fashion. One hundred-and-one published studies were examined. Recovery measurements were grouped as early, intermediate, late, psychomotor and adverse effects. With respect to induction of anaesthesia, propofol was superior to methohexital, etomidate and thiopental, but equal to sevoflurane and desflurane. Desflurane and sevoflurane were both superior to thiopental. There was no detectable difference between sevoflurane and isoflurane. With respect to the maintenance of anaesthesia, isoflurane and halothane were the worst. There were no significant differences between propofol, desflurane, sevoflurane and enflurane. Propofol is the induction agent of choice in day case patients. The use of a propofol infusion and avoidance of nitrous oxide may help to reduce postoperative nausea and vomiting.

Anaesthetic agents in paediatric day case surgery: do they affect outcome?

Both the numbers of children undergoing day case surgery and the type of procedures performed in this way are increasing. This expansion will only be beneficial if anaesthesia and surgery are provided with minimal post-operative morbidity e.g. postoperative delirium or nausea and vomiting. The choice of anaesthetic technique is considered critical to optimizing the service provided to patients and for this reason much research has addressed this question. This review considers the effect of anaesthetic technique on postoperative outcome in paediatric day case surgery. The outcome measures reviewed by this article are induction of anaesthesia, effects on the cardiovascular system, recovery from anaesthesia and postoperative nausea and vomiting. In each section both quantitative and qualitative outcome measures are discussed. Comparisons are made between sevoflurane and halothane, sevoflurane and propofol, propofol and halothane, desflurane and halothane and the presence or absence of nitrous oxide.

Anaesthesia clinical directors in the United Kingdom: organisation, objectives and support needs.

A postal survey of all 269 acute hospital trusts identified in the United Kingdom was carried out to study the work of Clinical Directors of anaesthesia. Initial responses from 163 Clinical Directors and 129 completed questionnaires were analysed. Four main areas of concern revealed by the survey were contracts and objectives, funding of managerial sessions, access to information and perceived need for support. Most Clinical Directors had no job description and most had no formal written objectives, despite a substantial body of advice that these should be provided. There was generally substantial underfunding of managerial hours compared with those actually worked and approximately 20% of Clinical Directors surveyed had no funding for managerial duties. Clinical Directors' ratings of the information available to assist their decision making were also a cause of concern. Clinical Directors perceived that they need better networking, more training particularly on human resource management and improved management information.

Anaesthesia for assisted conception: a survey of UK practice.

A telephone survey was undertaken of all UK centres (total 70) licensed for performing in vitro fertilization (IVF) and gamete intra-fallopian transfer (GIFT) by the Human Fertilisation and Embryology Authority (HFEA). The survey was carried out during the months of November and December 1997. Thirty-seven (52.1%) centres were in the NHS sector and 33 (47.8%) in the private sector. A response was available from 60 (84%) centres. A standard questionnaire was used which requested information about the procedures carried out, anaesthetic technique and pharmacological agents used. Forty-seven centres carried out IVF, two centres GIFT and 11 centres both. Out of 58 centres carrying out IVF, sedation was used in 28, general anaesthesia in 17, sedation combined with regional anaesthesia in seven and regional anaesthesia in one. Five centres gave a choice. Out of 22 centres using general anaesthesia for IVF, 12 used inhalational agents (isoflurane eight, enflurane four, sevoflurane two), eight used total intravenous anaesthesia (TIVA) with propofol and two centres inhalational agents or TIVA. Propofol was the induction agent in all but two centres. For IVF under sedation, 18 centres used midazolam, five used diazepam, three used opioids, one used entonox and the remaining ones a combination. When sedation was combined with regional anaesthesia, four centres used midazolam, two used propofol, one used midazolam with propofol, one used opioids and one used entonox. The regional technique in the 11 centres was either paracervical block with lignocaine (eight) or subarachnoid block with bupivacaine (three). Systemic analgesia was secured with fentanyl (22), pethidine (16), alfentanil (15), diclofenac (14), piroxicam (two), ketorolac (one) and ibuprofen (one). Five centres did not use any opioids; 40 centres did not use any nonsteroidal agents (NSAIDs). Out of the 13 centres that carried out GIFT, 12 used general anaesthesia while the thirteenth gave the patient a choice between general or regional anaesthesia. 11 centres used inhalational agents (isoflurane nine, enflurane two) while two used TIVA with propofol; propofol was the induction agent used in six centres while thiopentone was used in five. The range of analgesics was wide--fentanyl in six centres, alfentanil in three, morphine in two, diclofenac in five and ketorolac in one. Two centres did not use any opioids and seven centres did not use an NSAID. The only agreement at present appears to be that halothane is an unwise choice for IVF. No other technique has yet been proven to be either advantageous or detrimental.

Antagonism of rapacuronium using edrophonium or neostigmine: pharmacodynamics and pharmacokinetics.

We have studied the pharmacodynamics and pharmacokinetics of rapacuronium (Org 9487) in 70 healthy patients. Neuromuscular transmission was monitored using TOF stimulation of the ulnar nerve and mechanomyography of the adductor pollicis muscle. Half of the patients were given a single dose of rapacuronium 1.5 mg kg-1 and the remainder rapacuronium 1.5 mg kg-1 with three incremental doses of 0.5 mg kg-1, each given when T1/T0 had recovered to 25%. In all patients, neuromuscular block was antagonized using neostigmine 0.05 mg kg-1 or edrophonium 1.0 mg kg-1 (allocated randomly), 2 min after the final dose of rapacuronium. All patients developed complete block after rapacuronium 1.5 mg kg-1. Mean onset time was 66 (SD 24) s. In patients who received an antagonist 2 min after the first dose of rapacuronium, time to recovery of T1/T0 to 25% was similar after neostigmine (9.8 (3.8) min) and edrophonium (10.3 (4.3) min): in patients who received incremental doses of rapacuronium, spontaneous recovery of T1/T0 to 25% after the first dose was 18.9 (4.7) min. In those who received an antagonist 2 min after the first dose of rapacuronium, times to recovery of T4/T1 to 0.7 were also similar after neostigmine (23.7 (7.7) min) and edrophonium (29.1 (10.7) min). After three incremental doses of rapacuronium, there was a longer time to recovery of T1/T0 = 25% after neostigmine compared with edrophonium (5.1 (1.0) vs 3.3 (1.3) min; P < 0.05) but more rapid recovery to T1/T0 = 75% (10.1 (2.9) vs 16.8 (10.1) min; P < 0.05) and T4/T1 = 0.7 (19.8 (6.3) vs 35.1 (10.4) min; P < 0.05). A three-compartment pharmacokinetic model was justified. Typical values for clearance and initial volume of distribution (V1) were 4.4 ml kg-1 min-1 and 94.8 ml kg-1, respectively. In females, clearance was decreased by 38.5% compared with males and V1 was decreased by 25% in patients aged more than 65 yr.

The influence of premedication on heart rate variability.

Analysis of heart rate variability has been used to study the effects of midazolam, morphine and clonidine on the autonomic nervous system, when administered to patients for premedication. Ninety-five patients were studied 60 min before and 60 min after premedication. Normal saline (n = 25), midazolam 0.08 mg.kg-1 (n = 24), morphine 0.15 mg.kg-1 (n = 23), or clonidine 2 micrograms.kg-1 (n = 23) were administered intramuscularly by random allocation. A Holter device was connected to the patient during the study period. Using power spectral analysis the low-frequency and high-frequency components were calculated from the Holter recordings. These are markers for sympathetic and parasympathetic activity respectively; the low- to high-frequency ratio was also calculated, a ratio of > 1 signifying sympathetic dominance. A significant reduction was noticed in both low-frequency and high-frequency power in the three premedicated groups, whereas no changes were observed in the normal saline group. In the case of midazolam, both the low and high frequencies were decreased but the low- to high-frequency ratio did not change significantly. Morphine and clonidine depressed the low-frequency component more than the high-frequency component and the low- to high-frequency ratio was decreased, suggesting parasympathetic dominance. We conclude that heart rate variability may be a useful tool for investigating the effect of drugs on the autonomic nervous system.

A comparison of cisatracurium (51W89) and atracurium by infusion in critically ill patients.

OBJECTIVE: To evaluate and compare the safety and efficacy of cisatracurium (51W89) and atracurium administered by continuous infusion to critically ill patients requiring neuromuscular blocking agents to facilitate mechanical ventilation. DESIGN: Open, randomized, multicenter study of patients receiving cisatracurium or atracurium infusion to facilitate mechanical ventilation. SETTING: Five university teaching hospital intensive care units in the United Kingdom. PATIENTS: Sixty-one adult patients requiring neuromuscular blocking agents to facilitate mechanical ventilation. INTERVENTIONS: Bolus doses followed by continuous infusions of cisatracurium or atracurium were administered. Onset, maintenance, and recovery of neuromuscular blockade were measured, using transcutaneous ulnar nerve stimulation and an accelerometer. MEASUREMENTS AND MAIN RESULTS: Forty patients received cisatracurium (mean duration 48.1 +/- 4.2 [SEM] hrs), and 21 patients received atracurium (mean duration 46.1 +/- 5.8 hrs). The infusion rate for patients receiving cisatracurium was 3.1 +/- 0.2 microg/kg/min, and for patients receiving atracurium 10.4 +/- 0.9 microg/kg/min. There were no significant differences in mean times to 70% recovery of Train-of-Four ratio (cisatracurium 60 mins, atracurium 57 mins), although there was considerable interpatient variation (20 to 175 mins with cisatracurium vs. 35 to 85 mins with atracurium). One patient who received cisatracurium exhibited intermittent bronchospasm during and after the study period. CONCLUSIONS: Cisatracurium, an isomer of atracurium, appears to be a suitable agent for providing muscle relaxation in critically ill patients.

Rocuronium and cisatracurium.

Rocuronium and cisatracurium are the two most recent muscle relaxant additions to our pharmacopocia. These two drugs are significant advances and are likely to have an increasingly important role in clinical anaesthesia in the future.

Mivacurium or vecuronium for muscular relaxation in day-case surgery.

Anaesthetic agents for day-case surgery ideally should have a short duration of action. This study was designed to compare the efficacy and safety of mivacurium and vecuronium for healthy adults undergoing dental day-case surgery. Thirty fit healthy adult patients (ASA I or II) randomly received either mivacurium 0.15 mg kg-1 (n = 15) or vecuronium 0.1 mg kg-1 (n = 15). Anaesthesia included propofol, fentanyl, nitrous oxide and isoflurane. Maximum depression of T1 was greater in the vecuronium group (99.8%) than in the mivacurium group (98.3%). There was no difference between grade of intubation at 2 min between the two groups, although patients receiving vecuronium had a more profound block at the time of intubation than those who received mivacurium (89.2% vs. 78.9%). Recovery to 10% T1 was faster in the mivacurium group (11.2 min vs. 33.1 min). All patients in the vecuronium group received neostigmine at the termination of surgery. The neostigmine evoked recovery index in the vecuronium group (4.39 min) was less than the spontaneous recovery index in the mivacurium group (6.78 min). One patient in the mivacurium group had a low plasma cholinesterase concentration (0.43 ku L-1); recovery times however, fell within the 95% confidence intervals (CI) for the group. There was no correlation between cholinesterase levels and recovery time. Mivacurium may be the more appropriate agent for dental day-case surgery because it has a shorter duration of action and does not generally require antagonism with an anticholinesterase.

The effects of midazolam or propofol followed by suxamethonium on the QT interval in humans.

Prolongation of the QT interval may produce potentially hazardous arrhythmias. The effects of midazolam or propofol, followed by suxamethonium on the QT interval have been investigated. Thirty patients, ASA I or II, without cardiovascular disease, electrolyte abnormalities or receiving any medication were studied. All patients were premedicated with midazolam 0.08 mg kg-1 i.m., 30-60 min prior to surgery. Anaesthesia was induced with either midazolam 0.4 mg kg-1 i.v., (15 patients) or propofol 1 mg kg-1 i.v. bolus, followed by a continuous infusion (15 patients). ECG, heart rate and arterial pressure were measured before induction of anaesthesia and at 1 and 3 min after the bolus of midazolam or propofol. Further recordings were obtained at 1 and 3 min after a bolus of suxamethonium 1.5 mg kg-1 i.v. and also immediately after tracheal intubation and 1 min later. Neither midazolam nor propofol had any significant effect on QTc interval. Prolongation of QTc was observed in both groups after suxamethonium and this was further prolonged following intubation. Heart rate and arterial pressure were also increased significantly in both groups following intubation.