Introduction
Anesthesia has become more safe and comfortable for patients in recent years thanks to newly developed drugs and procedures. Short-acting drugs, such as remifentanil and propofol, provide hemodynamic stability and rapid postanesthetic recovery [
1]. However, due to global cost sensitive healthcare environment nowadays, clinical practitioners have to pay more attention to the cost-effectiveness of these newly developed methods [
1,
2]. Especially, it is of extreme importance to balance cost and efficacy of new drugs and procedures for the limited health care budget in China [
3]. Evaluation of cost-effectiveness of anesthetics should take into consideration the cost of agents, potency, waste, recovery and postoperative complications [
4,
5]. Both beneficial parameters and cost analysis guidelines have been suggested by previous researchers [
1,
4,
5]. And comparisons of different anesthesia methods have also been extensively reported [
1,
4,
5], but cultural and economic differences between different countries and different setting may make these costs vary significantly. Thus, this study was designed as a cost-benefit analysis for three widely practiced general anesthesia in our department.
Methods
After obtaining the approval of Institutional Review Board and written informed consent of the patients, 60 female patients who were scheduled for elective gynecological laparoscopic surgery under general anesthesia were enrolled in this prospective, single-blind study from March 1, 2008 to March 1, 2010. All the patients were at the age of 18-65 years, ASA I or II. Exclusion criteria for this study were as follows: (1) history of allergy to any of the drugs used in this study; (2) mental diseases; (3) neuropathies; or (4) surgical procedures lasting less than one hour. Patients were randomly divided into three groups according to a computer-generated randomization schedule: group V, group I and group C.
Anesthesia methods
Patients received i.m. atropine 0.01 mg·kg
-1 and luminal 2 mg·kg
-1 30 min preoperatively. After the patients arrived in the operating room, intravenous access and standard monitoring were established (pulse oximetry, noninvasive blood pressure, electrocardiogram and BIS (bispectral index)). In group V, anesthesia was induced with midazolam 0.05 mg·kg
-1, remifentanil 1 µg·kg
-1, propofol 1.5 mg·kg
-1, vecuronium 0.1 mg·kg
-1, and maintained with propofol 5-10 mg·kg
-1·h
-1 and remifentanil 0.2-0.3 µg·kg
-1·min
-1 infusion, which were stopped 2-3 min before the end of surgery. In groups I and C, anesthesia was induced with fentanyl 4 µg·kg
-1 and the same doses of midazolam, propofol, vecuronium as those in group V. In group I, anesthesia was maintained with 1-2.5 MAC isoflurane which was stopped 8-15 min before the end of surgery, and a bonus of 1 µg·kg
-1 fentanyl was given each hour. In group C, anesthesia was maintained with 0.6-1 MAC isoflurane which was stopped 8-10 min before the end of surgery, combined with propofol 2-3 mg·kg
-1·h
-1 and remifentanil 0.1-0.15 µg·kg
-1·min
-1 infusion which were stopped just at the end of surgery. All patients received vecuronium for muscle relaxation. The depth of anesthesia was monitored by BIS, to keep the BIS between 40 to 60 [
6]. If the hemodynamic changes exceeded more than 20% of the preoperative baseline, the doses of anesthetic agents were adjusted. If the hemodynamic changes exceeded 50% of the baseline or could not be controlled simply by adjusting the doses of anesthetic agents within the above-mentioned ranges, vasoactive agents such as dopamine or nicardipine were used. When the patients breathed spontaneously, neuromuscular blockade was reversed with i.v. neostigmine 0.02 mg·kg
-1 and atropine 0.01 mg·kg
-1. Tracheal extubation was performed when the patients achieved a regular respiratory frequency of more than 10 times·min
-1 and the tidal volume exceeded 6-8 ml·kg
-1. No prophylactic antiemetics were administered during anesthetic period.
Drugs and their prices included in this study
Midazolam: 2 ml: 10 mg, Nhwa. Pharma. Co., Nanjing, China; ¥25.1 Yuan/Amp;
Fentanyl citrate: 10 ml: 0.5 mg, Humanwell Pharma. Co. LTD., Yichang, China; ¥19.265 Yuan/Amp;
Vecuronium bromide: 4 mg/Amp, N. V. Organon, Netherlands; ¥ 28.2 Yuan/Amp;
Propofol: 20 ml: 200 mg, AstraZeneca UK Limited, UK; ¥94.54 Yuan/Amp;
Isoflurane (Aerrane): Baxter Healthcare Co., USA; ¥6.6 Yuan/ml;
Remifentanil: 1 mg/Amp, Humanwell Pharma. Co. LTD., Yichang, China; ¥106.96 Yuan/Amp;
Atropine sulfate: 1 ml: 0.5 mg, Harvest Pharma. Co. LTD., Shanghai, China; ¥0.35 Yuan/Amp;
Nicardipine hydrochloride: 2 ml: 2 mg, Astellas Pharma. Inc., Japan; ¥22.4 Yuan/Amp;
Dopamine hydrochloride: 2 ml: 20 mg, Harvest Pharma. Co. LTD., Shanghai, China; ¥0.69 Yuan/Amp;
Neostigmine methulsulfate: 2 ml: 1 mg, Xinyin Jinzhu Pharma. Co. LTD., Shanghai, China; ¥1.06 Yuan/Amp;
Tropisetron hydrochloride: 2 mg/Amp, Luoxin Pharma. Stock Co. LTD., Shandong, China; ¥ 60.1 Yuan/Amp;
Clinical parameters
The following parameters were recorded and compared among the 3 groups: (1) the cardiovascular reactions as shown by changes in mean arterial pressure (MAP) and heart rate (HR) during induction, tracheal intubation and extubation; (2) the incidences of adverse effects during intubation, including movement, coughing, hiccup and laryngospasm; (3) recovery time of spontaneous breathing and tracheal extubation from the end of all surgical procedures; (4) the duration of stay in post-anesthesia care unit (PACU)(Patients were allowed to leave PACU when the Aldrete recovery score[
7] was≥9); (5) observer’s assessment of alertness/sedation scales (OAAS) and verbal rating scale (VRS) scores (immediately after extubation, 1 h, 3 h, 24 h postoperatively), and demands for analgesics after surgery; (6) complications such as awareness during operation, postoperative shivering, headache, nausea and vomiting during the first postoperative 24 h, etc.; (7) postoperative patient satisfaction (“more pleasant”, “as pleasant as” or “worse” than expected) 24 h after the operation. BIS was monitored and kept around 40 to 60 during anesthesia.
Cost analysis
Cost of drugs per case was recorded including all those consumed during the anesthesia plus the waste, and the treatment of postanesthesia complications in the first 24 h postoperatively. Theoretically, the cost for the whole anesthesia comprises not only consumption of the drugs but payments for medical supplies, such as syringes, cannulas, depreciation of anesthesia machines and monitors, and salaries for all staff involved in the individual case. However, according to mainland China medical costing system, the last three items are charged equally depending on the anesthesia time and the grade-rating of the hospital, no matter how many syringes are used or how many physicians and nurses are involved in the individual case. Thus, we chose to analyze only the costs of drugs in the study.
Statistical analysis
Our prior power analysis was based on data from a pilot study of 48 patients (the study was presented as an abstract poster in ASA annual meeting, 2008) [
8]. A minimum of 6 patients were needed to be enrolled in each group in order to provide 80% power to detect a cost difference of RMB 100 Yuan at α = 0.05 (two-tailed test). The quantitative data were expressed as mean and standard deviation, and analyzed with one-way ANOVA. Bonferroni’s Post Hoc test was used to compare the differences between every two groups. The qualitative data were analyzed with Kruskal-Wallis rank test.
P<0.05 was considered statistically significant.
Results
1. Sixty adults scheduled for elective gynecological laparoscopic surgery under general anesthesia participated in this study. The demographic characteristics and the operation time were similar among the groups (Table 1).
2. General conditions during the operation and anesthesia. No movement, coughing, hiccup or laryngospasm was observed during tracheal intubation in all the patients. Cardiovascular reactions during intubation and extubation (systolic pressure varying over 20 mmHg or the heart rate varying over 20% than the baseline) were similar among groups. Although some patients needed medications, there was no statistically significant difference among above-mentioned groups (Table 2).
3. Emergence and recovery period. The average time of recovery of spontaneous breathing and tracheal extubation from the end of all surgical procedures was comparable in all 3 groups. Patients were allowed to leave PACU when the Aldrete recovery score [
7] was≥9, and the duration of stay in PACU was also similar among groups (Table 3).
4. Post-anesthesia period. There was no patient who was able to recall any intraoperative event in the study. All the postoperative complications among the patients were carefully recorded, more patients in group C complained nausea and vomiting postoperatively, but all symptoms were relieved in 48 h. The incidence of shivering was higher in group V. More patients suffered from dizziness in group C. Postoperative restlessness was recorded only in group I. In group C, one patient complaining of 3 h postoperative chest distress and another patient complaining of headache had their individual postoperative symptom relieved in the next day after continued mask-oxygen inhalation without any other treatments. However, these differences were not statistically significant (Table 4). The OAAS scores seemed slightly lower in group I immediately after tracheal extubation. The VRS scores were higher in group V 1 h after the operation and more patients needed analgesic treatments. Statistical analysis showed no significant differences (Table 5).
5. Patient satisfaction. Anesthesia satisfaction rating was asked of each patient 24 h after the surgery (Table 6). One patient in group V felt worse than expected as a result of severe postoperative nausea and vomiting postoperatively. There was no statistical significant difference in the patient satisfaction.
6. Costs of the anesthesia. Costs of all the drugs per case used during the procedure were calculated (Fig. 1). The costs in group I were the lowest, whereas those of group V were the highest in this study. There were significant differences among the three groups (P<0.05).
Discussion
General anesthesia is one of the most common anesthesia methods for gynecological laparoscopic surgery, due to the possible cardiovascular and respiratory disturbances from open-surgical manipulations. Different balanced anesthesia techniques including inhalational agents, intravenous agents and a variety of muscle relaxants have been reported and comprehensively reviewed [
9]. In mainland China, most patients pay a certain percentage for healthcare services themselves [
3]. According to one oral survey, safety and costs are the top two important concerns for patients. This is consistent with the worldwide concept of “value-based anesthesia care.” That is, the increased value can be obtained by achieving either the same outcome at a lower cost or a better outcome at the same or higher total cost [
5,
10]. As declared a decade ago by Watcha
et al., “Anesthesiologist, like all other specialists, needs to examine carefully their clinical practices so that excessive costs and waste can be reduced without compromising patient care or safety.” [
5] The costs of the anesthetics must be taken into consideration when certain anesthesia method is chosen in cost sensitive healthcare environment nowadays [
5].
Our current study evaluated the induction, emergence and recovery profiles, the complications, the patient satisfaction, and the costs of drugs used for three different anesthesia methods, which have been widely practiced in our department. The costs in group I were the lowest in this study, and there was no significant difference in complications and patients’ satisfaction compared with the other groups. As shown in previous studies, TIVA with propofol and remifentanil was proved to be suited to gynecological laparoscopic surgery because of its hemodynamic stability, rapid post-anesthetic emergence and recovery, and exceptional acceptance by the patients [
11,
12]. The results of group V in our study indicating patients in group V felt more comfortable than the other two groups, differ from some previous reports [
1]. In addition, our results showed that inhalational anesthetics, somehow, were able to offer a relatively comfortable anesthesia to patients with lower cost. The difference more than likely came from the cost of work force, drug prices and different health care charge policies. In our anesthesia protocol, isoflurane inhalation is stopped 8-10 min before the predicted end of surgery while intravenous infusion of propofol and remifentanil are stopped 2-3 min before that. Using this maneuver, similar recovery time is achieved among all the three groups. Our patient’s recovery profile was as good as other groups and more rapid when we carefully managed the withdrawal time.
Many previous studies showed that there was a higher incidence of postoperative nausea and vomiting (PONV) after combined anesthesia with isoflurane and fentanyl in comparison to TIVA with propofol and remifentanil [
13]. The incidences of PONV were similar between group V and group I, but higher in group C in our study though the difference was not significant statistically. Because most patients in our study were young female without a history of smoking, the laparoscopic surgeries
per se are correlated with a high incidence of PONV. The choice of anesthetics may have been an attributing factor for the incidence of PONV perioperatively reported by previous study [
14], but our study didn’t show such tendency. This is likely due to the limited sample size and uniform gender. The reason for higher morbidity of nausea and vomiting in group C may also be due to their receipt of more kinds of anesthetic agents. A greater sample size should be included to detect the statistical difference with the nonparametric test.
Conclusions
We conclude that with careful management of the withdrawal time, the combination of isoflurane and fentanyl anesthesia could provide a safe and satisfactory anesthesia for gynecological laparoscopic surgery with less cost compared with total intravenous anesthesia (TIVA) with propofol and remifentanil or the combination of both aforementioned two methods.
Higher Education Press and Springer-Verlag Berlin Heidelberg
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