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The efficiency of different adjunct techniques for regional anesthesia |
Pongraweewan O, Lertakyamanee J, Luangnateethep U, Pooviboonsuk P, Nanthaniran M, Sathanasaowapak P, Chainchop P |
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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 The following five different adjunct techniques for regional anaesthesia were examined.
Explanation and music: the patients listened to music and an explanation about the benefits and care during regional anaesthesia, via an earphone during the perioperative period. The explanation took 2 minutes and was repeated twice after which there was music. The patients set the volume of the music.
Subliminal audiotape: the patients listened to music with a subliminal message. The message contained suggestions about six different areas of well-being. The patients set the volume of the music.
Propofol patient-controlled sedation (PCS): the patients were instructed on how to use the PCS device and were given an explanation about the sedation properties of its content. The PCS was set to deliver propofol at a dose of 0.3 mg/kg for patients older than 60 years and 0.6 mg/kg for those in a younger age group, with a 3-minute lock-out interval.
Midazolam: the patients received a midazolam 0.05 mg/kg bolus. If the patient complained of discomfort or anxiety after the first dose of midazolam, midazolam 0.02 mg/kg or narcotics could be given.
Control: the patients received no adjunct techniques. Anxiolytic or analgesic drugs could be given by the attending anaesthesiologist if the patient complained of being anxious.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised adult patients with an ASA rating of I or II who were scheduled to undergo total knee replacement, or open reduction with internal fixation for fractured lower extremities, under regional anaesthesia. Patients with mental illness or with documented hearing loss were excluded, as were those having any contraindication to regional anaesthesia.
Setting The setting was a hospital. The economic study was carried out in Thailand.
Dates to which data relate The dates to which the effectiveness and resource use data referred were not reported. The price year was 2002.
Source of effectiveness data The effectiveness evidence was derived from a single study.
Link between effectiveness and cost data The costing was carried out prospectively on the same sample of patients as that used in the clinical study.
Study sample Power calculations were not reported. A sample of 110 eligible patients was enrolled in the study. There were 22 patients in each of the five groups. The mean age of the participants was 38.9 (+/- 18.5) years in the explanation and music group, 49.1 (+/- 22.1) years in the subliminal sound group, 43.9 (+/- 18.1) years in the propofol group, 45.9 (+/- 21.7) years in the midazolam group and 48.9 (+/- 21.8) years in the control group. The numbers of females were 9 (explanation and music), 12 (subliminal sound), 10 (propofol), 10 (midazolam) and 10 (control), respectively. It was not stated whether some patients refused to participate.
Study design This was a prospective, randomised controlled trial that was carried out at a single centre, the Siriraj Hospital in Bangkok, Thailand. Patient allocation to study groups was based on a random number table in an opaque envelope, which was opened after an adequate dermatomal level of anaesthesia for the particular procedure was confirmed and cardiorespiratory stability was ensured. The patients were followed for a maximum of 36 hours postoperatively. No patient was lost to the follow-up assessment. Nurse anaesthetists, who were blinded to the adjunct technique the patient had received, assessed satisfaction postoperatively.
Analysis of effectiveness The analysis of the clinical study was conducted on an intention to treat basis. The outcome measures used were sedation score, anxiety score and satisfaction score. Complications, including haemodynamic instability, were also evaluated.
Haemodynamic instability defined hypotension as a systolic blood pressure (BP) <30% of baseline value, hypertension as a systolic BP>30% of baseline values, bradycardia as a heart rate <60 beats/minute, tachycardia as a heart rate >120 beats/minute, and hypoxemia as an oxygen saturation of <92% for more than 5 seconds. Anxiety was assessed by a verbal analogue score (visual analogue scale, VAS) ranging from 0 (complete relaxation) to 100 (the worst feeling of anxiety possible). Sedation was measured using an alertness/sedation scale. The sedation score and anxiety VAS were obtained 1 hour into the operation and at the end of the operation. Sedation scores were also obtained at 10 minutes, 15 minutes and 24 hours postoperatively. The satisfaction score was determined using a verbal analogue score (VAS), with 0 meaning totally unsatisfied and 100 the highest satisfaction that is possible at the end of the operation, 30 minutes, and 24 to 36 hours postoperatively.
The study groups were comparable at baseline in terms of their demographic characteristics, duration of adjunct technique, type of operation, method of regional anaesthesia and drugs received.
Effectiveness results Anxiety scores were not significantly different between the groups at any time.
Differences in the sedation score reached statistical significance only at 1 hour into the operation. The average (min; max) values were 5 (4; 5) in the explanation and music group, 5 (4; 5) in the subliminal sound group, 5 (2; 5) in the propofol group, 4 (2; 5) in the midazolam group and 5 (4; 5) in the control group. Thus, the sedation score in the midazolam group was significantly lower than that in the control group, (p=0.000).
The satisfaction scores at end of the operation were 79.56 (+/- 22.57) in the explanation and music group, 83.64 (+/- 21.72) in the subliminal sound group, 96.82 (+/- 7.16) in the propofol group, 97.27 (+/- 11.93) in the midazolam group and 88.18 (+/- 18.16) in the control group, (p=0.012).
The satisfaction scores at 30 minutes postoperatively were 81.36 (+/- 20.31) in the explanation and music group, 82.73 (+/- 19.32) in the subliminal sound group, 96.36 (+/- 7.27) in the propofol group, 93.14 (+/- 11.68) in the midazolam group and 88.64 (+/- 18.07) in the control group, (p=0.009). Thus, the satisfaction score in the explanation and music group was significantly lower than that in the propofol group.
Eight patients in the propofol group and five in the midazolam group became hypoxemic and were treated with oxygen via a facemask. Three patients in each group needed airway adjuncts to maintain the airway patency.
Clinical conclusions The effectiveness analysis showed that patients in the midazolam group were significantly more sedated than the control group at 1 hour into the operation. The group that listened to an explanation and music were significantly less satisfied than the propofol group at the end of the operation and 30 minutes postoperatively. However, the authors argued that such statistical differences were not clinically relevant.
Measure of benefits used in the economic analysis The summary benefit measure was the satisfaction score. This was derived directly from the effectiveness analysis.
Direct costs The perspective adopted in the study was unclear. The health services included in the economic evaluation were labour and material (monitoring equipment), resources associated with the adjunct technique (earphones, tape cassette and drugs), and rescue drugs. The unit costs were presented separately from the quantities of resources used for some items. The labour costs were derived from a published study that used salary and fringe benefits. The other costs were presumably derived from the authors' institution. The resource use data were estimated from the sample of patients included in the clinical trial. Discounting was not relevant as the costs were incurred during a short timeframe. The price year was 2002, and a 5% inflation rate was used to update costs estimated in previous years.
Statistical analysis of costs The costs were treated deterministically.
Indirect Costs The indirect costs were not considered in the economic evaluation.
Sensitivity analysis Sensitivity analyses were not carried out.
Estimated benefits used in the economic analysis See the 'Effectiveness Results' section.
Cost results The estimated per patient costs were THB 385.06 in the explanation and music group, THB 590.87 in the subliminal sound group, THB 684.59 in the propofol group, THB 557.69 in the midazolam group and THB 509.34 in the control group.
Synthesis of costs and benefits An incremental cost-effectiveness ratio was calculated to combine the costs and benefits of the explanation and music group in comparison with the propofol group.
The cost per patient in the explanation and music group was THB 299.53 lower than that in the propofol group. However, the satisfaction score was 17.26 lower in the explanation and music group. Thus, if propofol was preferred to explanation and music in 100 patients, then THB 29,953 more would be needed. This would enable the satisfaction score to be increased from 79.6 to 96.8 at the end of the operation and from 81.4 to 96.4 at 30 minutes after the operation. However, this would not increase satisfaction at 24 to 36 hours postoperatively.
Authors' conclusions The use of explanation and music as an adjunct technique for patients undergoing orthopaedic procedures under regional anaesthesia in Thailand was cost-effective. Although propofol patients were significantly more satisfied, such differences were not clinically relevant.
CRD COMMENTARY - Selection of comparators The selection of the comparators appears to have been appropriate, as several strategies for the sedation of patients during regional anaesthesia were considered in the analysis. You should decide whether they are valid comparators in your own setting.
Validity of estimate of measure of effectiveness The use of a clinical trial was appropriate for the study question. Information on the approaches used to select the sample and to randomise patients to the study groups was reported. However, it was not stated whether some patients refused to participate in the study. Similarly, the period during which the clinical outcomes were gathered was not reported. The patient groups were comparable at baseline. A nurse, blinded to the adjunct technique the patients received, assessed the main clinical outcome, which further enhances the robustness of the analysis. Patient satisfaction was evaluated using validated instruments. Some limitations to the validity of the study should be noted. No evidence on the appropriateness of the sample size was provided and the use of power calculations was not reported. The evidence came from a single institution, thus caution is required when extrapolating the results of the analysis to other centres.
Validity of estimate of measure of benefit The summary benefit measure was specific to the interventions examined in the study. It is not comparable with the benefits of other health technologies. The impact of the interventions on quality of life was not assessed.
Validity of estimate of costs The perspective adopted in the study was not explicitly stated, although it might have been that of the authors' institution. The unit costs were reported for almost all items, but the quantities of resources used were provided only for a few resources. With the exception of labour costs, which were derived from a published study, the source of the cost data was not reported. The price year was provided, which will facilitate reflation exercises in other settings. No statistical analyses of the costs were performed. The cost estimates were specific to the study setting.
Other issues The authors reported the results of other studies in a narrative way. The issue of the generalisability of the study results to other settings was not explicitly addressed and sensitivity analyses were not performed. Thus, the external validity of the analysis was low. The study referred to patients undergoing orthopaedic surgery under regional anaesthesia, and this was reflected in the authors' conclusions.
Implications of the study The authors recommended explanation and music as an adjunct technique for patients undergoing orthopaedic procedures under regional anaesthesia. It was also suggested that the patients should choose the music.
Bibliographic details Pongraweewan O, Lertakyamanee J, Luangnateethep U, Pooviboonsuk P, Nanthaniran M, Sathanasaowapak P, Chainchop P. The efficiency of different adjunct techniques for regional anesthesia. Journal of the Medical Association of Thailand 2005; 88(3): 371-376 Other publications of related interest Gan TJ. Patient controlled antiemesis: a randomized, double-blinded comparison of two dose of propofol versus placebo. Anesthesiology 1999;90:1564-70.
Lepage C, Drolet P, Girard M, Degagne R. Music decreases sedative requirements during spinal anesthesia. Anesth Analg 2001;93:912-6.
Ganapathy S, Herrick IA, Gelb AW, Kirkby J. Propofol patient-controlled sedation during hip or knee arthroplasty in elderly patients. Can J Anaesth 1997;44:385-9.
Indexing Status Subject indexing assigned by NLM MeSH Adult; Anesthesia, Conduction /economics /methods; Cost-Benefit Analysis; Female; Humans; Hypnotics and Sedatives /economics /therapeutic use; Male; Midazolam /economics /therapeutic use; Middle Aged; Music Therapy /economics /methods; Orthopedic Procedures; Preoperative Care; Propofol /economics /therapeutic use; Prospective Studies; Tape Recording AccessionNumber 22005006291 Date bibliographic record published 31/03/2006 Date abstract record published 31/03/2006 |
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