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Cost-effectiveness of inhalational, balanced and total intravenous anaesthesia for ambulatory knee surgery |
Alhashemi J A, Miller D R, O'Brien H V, Hull K A |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology Inhalation, balanced and total intravenous anaesthesia for ambulatory knee surgery.
Economic study type Cost-effectiveness analysis.
Study population ASA Physical Status I-II patients undergoing arthroscopic knee surgery in an ambulatory care setting. Exclusion criteria were reported as follows: patient preference for regional anaesthesia; age less than 20 years or above 60 years; body mass index either less than 20 or above 30 kg
Setting Ambulatory care, hospital. The study was carried out in Ottawa, Ontario, Canada.
Dates to which data relate No dates for data collection were provided. The price year was not reported.
Source of effectiveness data Effectiveness data were derived from a single study.
Link between effectiveness and cost data The costing was undertaken prospectively on the same patient sample as that used in the effectiveness study.
Study sample A total of 93 patients (31 patients per group) was included in the study based on power calculations. No dropouts occurred.
Study design Randomized double-blind controlled trial performed in a single centre. A blinded observer recorded all post-operative data. The duration of follow-up was 36 hours postoperatively.
Analysis of effectiveness The analysis was based on the intention to treat principle. The primary health outcome was the recovery profile at the post anaesthetic care unit (PACU), which was assessed every 15 minutes using a modified Aldrete scoring system and the post-anaesthesia discharge scoring system (PADS). In addition, incidence of nausea and vomiting during hospital stay and until 24 hours after discharge were recorded. The patient satisfaction with the anaesthetic option was evaluated by means of a telephone interview at 24-36 hours postoperatively. Groups were shown to be comparable in terms of age, sex, weight, ASA status, and intraoperative measurements (HR, SBP values).
Effectiveness results The mean time to emergence (eye opening) and response to command were (SD) 2.2 minutes (+/- 1.5) and 3.0 (+/- 3.2) minutes, respectively in the BAL group, whereas the corresponding figures in the TIVA group were 8.8 (+/- 4.4) and 9.2 (+/- 4.5) minutes, and in the INH group 8.5 (+/- 4.8) and 8.9 (+/- 5.4) minutes, respectively. These two measures of recovery time were statistically significantly shorter in the BAL group that in the other two groups (p<0.0001). In the BAL group, 48% of patients experienced nausea and/or vomiting (although only half of those needed treatment with antiemetic medications) compared with 23% and 16% of patients in the INH and TIVA groups, respectively (p<0.02). Overall patient satisfaction and mean times to discharge from PACU and hospital were rapid and similar in all three groups. Intraoperatively, no patient experienced surgical or anaesthesia-related complications of 'clinical importance'.
Measure of benefits used in the economic analysis Since no differences were found in overall patient satisfaction or overall recovery time, the economic analysis was based on costs only.
Direct costs Cost estimates included anaesthetic and postoperativedrugs, and bedside nursing time. Quantities of resource use were not reported separately from the costs. The unit costs were based on the purchasing price of the anaesthetic drugs (as of 1995) and the average salary of middle rank nurses during the study (dates not specified). The costs associated with the expenditures on nitrous oxide and oxygen were excluded. The overall price year was not reported.
Sensitivity analysis No sensitivity analysis was performed.
Estimated benefits used in the economic analysis Cost results The mean total cost per patient (SD) was Can$36.4 (+/- 5.3), Can$66.5 (+/- 11.7), and Can$86.2 (+/- 20.6)for the INH, BAL and TIVA groups (p<0.001), respectively.
Synthesis of costs and benefits Authors' conclusions For arthroscopic knee surgery, INH anaesthesia with isoflurane/fentanyl/N2O (INH) is associated with similar hospital discharge times, and comparable levels of patient satisfaction as either BAL or TIVA. The BAL option results in the most rapid time to awakening, but has a higher incidence of postoperative nausea and vomiting. Overall, INH had the lowest anaesthetic costs, and similar nursing and extra in-hospital costs. Therefore, there appears to be a potential pharmacoeconomic benefit associated with theuse of a "standard" isoflurane/fentanyl/N2O anaesthetic for brief outpatient surgery.
CRD COMMENTARY - Selection of comparators A justification was given for comparator used. The isoflurane/fentanyl/N2O (INH) strategy was reported as the standard inhalational anaesthetic. You, as a user of this database, should consider whether these are widely used technologies in your own setting.
Validity of estimate of measure of benefit The estimates of effectiveness were based on a small randomised, double-blinded clinical trial. The sample size was determined using power calculation. The internal validity of such a study is generally considered high. The authors noted that different opioids were administered in different relative doses to the threegroups.
Validity of estimate of costs Quantities of resource use were not reported separately from the costs. However, adequate details of cost estimation were provided. The dates associated with the data collection or prices used were not provided. The cost associated with the expenditures on nitrous oxide and oxygen were omitted. Also, the cost of time spent in different units (operating room, PACU, DCU) was not accounted for.
Other issues The authors' conclusions are justified given the uncertainties in the data. Some reservations, however, are warranted considering the completeness of the cost estimation. The results obtained from a single hospital may not be generalisable to the other settings, or other countries. No sensitivity analysis was carried out in order to enhance generalisability.
Source of funding Supported by a research grant from Janssen-Ortho Inc, Canada.
Bibliographic details Alhashemi J A, Miller D R, O'Brien H V, Hull K A. Cost-effectiveness of inhalational, balanced and total intravenous anaesthesia for ambulatory knee surgery. Canadian Journal of Anesthesia 1997; 44(2): 118-125 Indexing Status Subject indexing assigned by NLM MeSH Adult; Aged; Anesthesia, Inhalation /economics; Anesthesia, Intravenous /economics; Cost-Benefit Analysis; Double-Blind Method; Female; Humans; Knee Prosthesis; Male; Middle Aged; Postoperative Care; Prospective Studies AccessionNumber 21997000343 Date bibliographic record published 31/01/1999 Date abstract record published 31/01/1999 |
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