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Pharmacoeconomics of intravenous regional anaesthesia vs general anaesthesia for outpatient hand surgery |
Chilvers C R, Kinahan A, Vaghadia H, Merrick P M |
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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 Intravenous regional anaesthesia or general anaesthesia in outpatient hand surgery.
Economic study type Cost-effectiveness analysis.
Study population Patients undergoing hand or wrist surgery within an institutionand receiving either GA or IVRA.
Setting Hospital. The economic analysis was conducted in Vancouver, British Columbia, Canada.
Dates to which data relate Data on effectiveness and resources were collected in 1994. 1995 prices were used.
Source of effectiveness data Effectiveness data were taken from a single study.
Link between effectiveness and cost data Costing was undertaken retrospectively on the same patient sample as used in the effectiveness analysis.
Study sample 121 patients were retrospectively identified as having had appropriate IVRA or GA interventions within the time frame of the study. Initially 337 patients had been identified, but 152 were excluded:27 for having surgery which could only be performed by GA, 106 who had carpal tunnel release surgery, 10 who received a different type of anaesthetic and 9 for whom complete records were unavailable. The mean age of patients in the IVRA groups and the GA groups respectively were 45 (+/- 16) and 38 (+/- 13).54% of the IVRA group and 61% of the GA group were female. Power calculations were not used to determine the sample size and all patients meeting the criteria for the study were included in the analysis.
Study design The study was a single centre non-randomized controlled study with concurrent controls. The duration of follow up was to discharge from hospital. There was no loss to follow up.
Analysis of effectiveness The analysis of effectiveness was based on intention to treat. The primary health outcomes used in the analysis were adverse complications incurred. In addition, the level of unsuccessful IVRA procedures requiring readministration or switching to GA were also recorded. The IVRA and GA groups had no significant differences except in terms of age (see above), (P<0.001), and the number of operations undertaken for reduction and/or fixation of fracture and excision of lesion wrist joint, which were both higher in the GA group (P<0.05).
Effectiveness results There were significant differences in the rates of complications in terms of vomiting and dizziness: 0% in the IVRA group and 5% in the GA group, (P<0.05). There were no significant differences in the rate of complications for bronchospasms (IVRA: 0% and GA: 2%) and urticaria arm (IVRA: 2% and GA: 0%). IVRA was less successfully implemented than GA: 7% of the IVRA required local anaesthetic infiltration, 2% of blocks were redone and 2% were switched to GA. None of the GA patients required additional anaesthesia interventions (P<0.01).
Clinical conclusions IVRA was as effective as GA, although significantly less successful in administration and some complications such as vomiting and dizziness were more commonly associated with the GA group. No patient in either group required overnight admission. The time taken for recovery in the IVRA group was found to be lower than that for the GA group although there were more difficulties in administering anaesthetic using IVRA.
Measure of benefits used in the economic analysis Since the effectiveness analysis showed that IVRA was as effective as GA, the economic analysis was based on the difference in costs alone.
Direct costs Direct hospital costs of anaesthesia and recovery for both groups were estimated. Specifically these costs included anaesthesia (supplies, sterilization, drugs, gases) and recovery (supplies, drugs, and nursing time). Sterilization costs were calculated by the Sterile Supply Department. It was assumed that unused drugs in ampoules were wasted. Gas costs included the cost of isoflurane which was derived from a published formula. Oxygen and nitrous oxide costs were calculated using hospital cost estimates and the average cost of an hour of nursing time in the hospital's day care centre in 1995 was used for nursing time costs. Nursing time was based on the time spent in the post-anaesthesia recovery unit and additional time to discharge. Physician costs were not included in the analysis and nor were capital depreciation charges which were common to both interventions. 1995 prices were used. Resource quantities were not reported separately from costs.
Sensitivity analysis No sensitivity analysis was conducted.
Estimated benefits used in the economic analysis Cost results The median total costs of treatment in patients using IVRA and GA were Can$24.60 and Can$48.66 respectively, (P<0.00001). These costs included the costs of complications incurred in both groups and, where patients were switched from IVRA to GA, these costs were included in the total costs of the IVRA group. Costs were up to the point of discharge following surgery and no patient remained in hospital overnight.
Synthesis of costs and benefits Authors' conclusions The authors concluded that the costs of anaesthesia and recovery using IVRA were less than half those of general anaesthesia for patients undergoing hand surgery at the institution and that IVRA was associated with a shorter recovery time and fewer post operative complications, even though it was less effective in achieving satisfactory anaesthesia. The authors noted the limitations of their study but felt that the magnitude of the difference in costs between the GA and IVRA groups was similar to that demonstrated in other studies.
CRD COMMENTARY - Selection of comparators A justification was given for the comparators used. IVRA represents a low technology alternative technique to general anaesthesia, which is an accepted standard for hand surgery.
Validity of estimate of measure of benefit The study was based on a non-randomised trial in a single institution and did not use power tests to generate a significant sample size. Thus the sample may be biased, particularly as there were significant age differences between the two groups. The only health outcomes measured were complications incurred before discharge and it may be that post discharge complications should also have been considered.
Validity of estimate of costs Adequate details were provided of the source of costs and resources used in the analysis. Costs were estimated only from the perspective of the institution and excluded costs experienced by others in society such as patients and caregivers.
Other issues The cost data and resource use data, as the authors recognised, are not generalisable outside the institution, either to other parts of Canada or elsewhere. No sensitivity analysis was undertaken to examine the robustness of the costs. Although studies of this type are limited, another study in Canada demonstrated a similar differential between IVRA and GA. The results of the study would nevertheless have been strengthened by evidence of a systematic literature review.
Bibliographic details Chilvers C R, Kinahan A, Vaghadia H, Merrick P M. Pharmacoeconomics of intravenous regional anaesthesia vs general anaesthesia for outpatient hand surgery. Canadian Journal of Anesthesia 1997; 44(11): 1152-1156 Indexing Status Subject indexing assigned by NLM MeSH Adult; Ambulatory Surgical Procedures /adverse effects /economics; Anesthesia, General /adverse effects /economics; Anesthesia, Intravenous /adverse effects /economics; Costs and Cost Analysis; Female; Hand /surgery; Humans; Male; Middle Aged; Recovery Room /economics; Retrospective Studies; Time Factors AccessionNumber 21997001612 Date bibliographic record published 28/02/1999 Date abstract record published 28/02/1999 |
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