Abstract
Objectives
To compare the efficacy and side effects of epidural patient-controlled analgesia (EPCA) with those of intravenous patient-controlled analgesia (IVPCA) in fast-track video-assisted thoracoscopic (VATS) lobectomy.
Patients and methods
EPCA or IVPCA was chosen by patients and was started immediately following tracheal extubation in the wake of completion of VATS lobectomy. EPCA analgesia was carried out with the PCA device programmed to deliver a bolus dose of 3 mL of 0.1% bupivacaine combined with 1.2 μg/mL fentanyl, and continuous epidural infusion at a rate of 4 mL/hour through an epidural catheter placed at the T6-7 or T7-8 level. IVPCA was made possible by a patient controlled infusion pump programmed to deliver 0.1% morphine with a loading dose of 3 mg, and the controlled bolus of 1 mg, at a lockout interval of 5 minutes. A rescue dose of 5 mg intravenous morphine was available for all patients in postoperative care unit. Pain management was assessed with visual analog scale at rest (VAS-R) and during motion (VAS-M); side effects including nausea, vomiting, pruritus, dizziness and sleepiness were recorded and analyzed from postoperative Day 1 (POD1) to Day 3 (POD3).
Results
This study included 105 patients. Satisfactory pain control was achieved, although 9/70 patients in the EPCA group and 5/35 patients in the IVPCA group needed rescue morphine in the recovery room. The VAS-R was significantly higher on POD1 than on POD2 or POD3 in both groups (p < 0.001). The VAS-R and VAS-M were comparable in both groups on POD1 and POD3 but significant lower VAS-M was seen in the EPCA group on POD2 (p = 0.008). Higher incidence of dizziness was found in the IVPCA group on POD1 (p = 0.044) but the EPCA group had a higher incidence of pruritus on POD2 (p = 0.024) and POD3 (p = 0.03).
Conclusion
Our results indicated that the necessity of pain control was higher on POD1 for VATS lobectomy. Both EPCA and IVPCA can provide an adequate, continuous and effective means for postoperative pain management and a lower VAS-M was found in EPCA on POD2.
Keywords
analgesia, epidural: thoracic; analgesia, patient-controlled; thoracic surgery, video-assisted; thoracic surgical procedures: lobectomy;
1. Introduction
Video-assisted thoracic surgery (VATS) is rapidly gaining acceptance to supersede traditional thoracotomy, due to it having lower postoperative morbidity, and less postoperative pain, in addition to its lower cost. Although many previous studies showed that the need of epidural analgesia for pain after VATS surgery was decreased,1, 2, 3, 4 they also demonstrated that analgesia in VATS patients especially on postoperative Day 1 (POD1) was indispensable. However, most of the previous studies on pain management for VATS were carried out in patients bearing different surgical trauma5 such as lobectomy, wedge resection, or pleurodesis, who needed postoperative ventilator support. As the "fast-track" VATS, with limited compromise of lung function6, 7 and shorter hospitalization, has grown in popularity recently,8, 9, 10 continuous, adequate postoperative pain control should be started immediately following tracheal extubation in the operation room. However, there are few studies comparing the efficacy of epidural patient-controlled analgesia (EPCA)11 with that of intravenous PCA (IVPCA), although both of them are considered favorable and satisfied pain management individually following fast-track VATS surgery.
In our hospital, patients scheduled to receive thoracic surgery including thoracotomy, VATS lobectomy, and wedge resection were asked whether they would choose routine parenteral analgesia, EPCA, or IVPCA analgesia by the staff of the acute pain service (APS) team after thorough explanation. However, we found that the choice of analgesic was different in variable VATS surgeries (unpublished data). In consideration of the risk of the thoracic epidural technique, we ventured to carry out a retrospective study to compare the efficacy of pain relief and side effects of EPCA with that of IVPCA following fast-track VATS lobectomy.
2. Methods and patients
After approval was obtained from the institutional ethical review board, the retrospective study was conducted. We reviewed the anesthetic, surgical, and pain control records of all patients who completed 3-day postoperative analgesia via EPCA or IVPCA from January to June 2011. Patients who received VATS lobectomy and were extubated in the operation room were included for analyses. Exclusion criteria included emergency cases of American Society of Anesthesiologists physical status III or above.
2.1. Choices of EPCA or IVPCA for postoperative pain management
Thorough explanation to the patient by our staff of APS team of the particulars of EPCA or IVPCA analgesia, which the patient chose at will, regardless of details of the anesthesia and operation was carried out the day before operation. Preoperative assessment was completed by the anesthesiologists who conducted the anesthesia with or without placing epidural catheter dependent on the type of PCA used. The APS nurses were responsible for providing PCA immediately after tracheal extubation, and undertook postoperative assessment of pain management and side effects from POD0 to POD3.
2.2. Placement of epidural catheter, and EPCA application
The epidural catheter was placed before general anesthesia through the interspace between the sixth and seventh or seventh and eighth thoracic vertebral bodies using a loss of resistance to air for confirmation; the tip was anchored 4 cm upward. Intravascular or intrathecal catheter placement was excluded with a test dose of 3 ml lidocaine (2%) with 1:200,000 epinephrine. After confirming the right placement of the catheter and effectively providing analgesia, general anesthesia was induced, and the infusion of 2% lidocaine was started immediately at a rate of 60 mg/hour.
2.3. Fast-track VATS lobectomy
General anesthesia was induced with propofol, 2 to 5 μg/kg of fentanyl, and vecuronium or cisatracurium. Following tracheal intubation, anesthesia was maintained with sevoflurane or desflurane in O2. VATS lobectomy was performed with three surgical ports, each of which was about 12 mm. Upon completion of VATS lobectomy, the trachea was extubated right away after reversal of muscle relaxation. EPCA or IVPCA (with 0.1% morphine) was available. The infusion pump for EPCA or IVPCA was provided immediately upon admission to the postanesthetic care unit or intensive care unit. A rescue dose of 5 mg intravenous morphine was allowable and given by APS nurses for acute intractable pain. Criteria for discharge from the postanesthetic care unit were stable vital signs with pain response on a visual analog scale (VAS) <4.
2.4. Application of EPCA or IVPCA after VATS
Postoperative EPCA analgesia was started by the patient with a controlled 3 mL bolus dose of 0.1% bupivacaine combined with fentanyl 1.2 μg/mL, and continuous epidural infusion at a rate of 4 mL/hour. The patients choosing IVPCA received 0.1% morphine intravenously with the patient controlled infusion pump after emergence from anesthesia with cognitive power for self-analgesia. The loading dose was 3 mg morphine, and the patient controlled bolus dosage was 1 mg, with a lock-out interval of 5 minutes.
2.5. Postoperative assessment of pain management and side effects
Pain scores were assessed and recorded by the nurses of APS team at rest (VAS-R, 0–10) and during motion (including getting off from the bed and walking) (VAS-M, 0–10) for 3 days. Side effects were also recorded on each POD.
Data are expressed by mean ± standard deviation. The sequential changes of VAS-R, VAS-M, and (VAS-M – VAS-R) in each group from POD1 to POD3 were analyzed by two-way repeated ANOVA with all-pairwise multiple comparison procedure. The incidences of postoperative complications including nausea, vomiting, dizziness, sleepiness, and skin itching were compared with two-way ANOVA using categorical variable. A p < 0.05 was considered statistically significant. Power of performed test was designated with alpha = 0.05 was 0.9.
3. Results
In total, 105 VATS patients (70 with EPCA and 35 with IVPCA) who were extubated in the operation room were included in this retrospective study. The patients' characteristics and operation data are shown in Table 1. The total volume of anesthetic infused to the EPCA group in 3 days was 201 ± 52 ml. The total dose of morphine infused to the IVPCA group in 3 days was 35.5 ± 20.7 mg. The number of hospitalization days was comparable between groups. Nine and five patients received a dose of rescue morphine, respectively, in the EPCA and IVPCA groups in the recovery room (within 60 minutes after extubation).
3.1. The efficacy of pain management
The VAS-R in the IVPCA group appeared to be slightly higher than that in the EPCA group but the difference was not statistically significant (Table 2). As shown in Fig. 1, the VAS-R was significantly higher on POD1 than that on POD2 and POD 3 for each group (p < 0.001). VAS-M on POD1 was significantly higher than that on POD2 or POD3 in the EPCA group but was not statistically significant in the IVPCA group. The VAS-R and VAS-M did not differ significantly between groups on POD1 and POD 3, but the VAS-M was significantly lower on POD2 in the EPCA group (as Table 2). There were no significant differences in VAS-M and VAS-R between groups.
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3.2. Assessment of side effects
As shown in Table 3, significantly higher incidence of sleepiness was seen on POD1 in both groups. Comparing the side effects between groups, a higher incidence of dizziness was found in IVPCA group than in EPCA group on POD1 (p = 0.044) and EPCA group had a significantly higher incidence of pruritus on POD 2 and POD3.
4. Discussion
The main findings in this study were: (1) EPCA and IVPCA achieved comparable efficacy of pain control for fast-track VATS lobectomy; (2) the VAS was slightly but significantly higher on POD1 than on POD2 or POD3 in both groups; (3) the VAS at resting or during movement was comparable in both groups on POD1 but EPCA had significant lower VAS-M than the IVPCA group on POD 2; and (4) IVPCA had a higher incidence of dizziness on POD1 but EPCA group had a higher incidence of pruritus on POD2 and POD3.
Effective and continuous pain management is essential for early ambulation and smooth recovery after fast-track VATS-lobectomy. With the use of insignificantly different morphine for rescue in PACU, we considered that the pain management immediately after tracheal extubation was comparably good. In this study, it implied that IVPCA could work as effectively as did EPCA for patients undergoing VATS lobectomy. Unlike a previous report of patient-controlled analgesia for thoracotomy,12 EPCA seemed not superior to IVPCA in VATS lobectomy. The necessity of EPCA should be reconsidered in patients undergoing VATS lobectomy while considering the risks of inserting thoracic epidural catheter.13 Our results agreed with those of the prospective study of Kim et al14 in comparable postoperative pain control, but the incidences of side effects were different, in that our study had larger patient groups with different analgesic formulae.
The pattern and amplitude of VAS were comparable in EPCA and PCA groups. VAS-R and VAS-M started to go downgrade on POD2 in both groups. However, the VAS-M of EPCA was significantly lower on POD2 in comparison with that of the IVPCA group. The lower VAS-M with EPCA might be beneficial on rehabilitation and ambulation. However, as to hospitalization days, our data did not involve the costs of hospitalization. The different route and dosage of drugs may explain the different trends of VAS-M. As pain began to fade from POD2, continuous use of EPCA could be adequate but the patients of IVPCA would reduce the bolus rate by if they had satisfactory pain control. This phenomenon was also suggested by the steady VAS-M through POD1-3 in PCA group. In this study, the difference (VAS-M – VAS-R) may serve as an indicator of difficulties with ambulation. However, there were no significant difference in (VAS-M – VAS-R) between groups, with slightly lower VAS-R in EPCA group.
EPCA has been considered to have the benefits of reduction of the need of prolonged ventilation or reintubation, improving lung function and maintaining good oxygenation despite a higher risk of hypotension, urinary retention, and pruritus, and possible technical failure. Based on our results of fast-track VATS lobectomy, preoperative evaluation, ventilation training, early tracheal extubation, and ambulation in the EPCA group did not appear to be superior to the IVPCA However, patients who did not complete the 3-day IVPCA with morphine were not included in this study. EPCA may have some benefits such as better quality of activities11, 15 or less stress-induced immunosuppression,16which we did not investigated in this study.
Our results showed a higher incidence of sleepiness on POD1 in both groups, which might be due to the effects of general anesthesia as well as the application of the rescue intravenous morphine. Like the previous investigations, the incidences of different side effects also varied between EPCA and IVPCA. Dizziness was found more often in the patients receiving IVPCA on POD1, while in the EPCA group a higher incidence of pruritus was seen on POD2 and POD3. The incidences of nausea and vomiting were higher on POD2, disregarding the analgesic modality while the VAS scores were lower than that of POD1. Although we were concerned with urinary retention in EPCA or IVPCA, the data did not show different criteria on removing the Foley catheter at the desire of different surgeons.
There were limitations in this study. Firstly, this was a retrospective but not a double-blind prospective investigation; secondly, we could not measure the pain scores by the same method in early ambulation such as the same distance of walking or the same respiration practice. However, we still demonstrated that despite the different PCA modality, the pattern and the timing of analgesia were similar between IVPCA and PCEA.
Anesthetic techniques have always had to adapt to changing surgical interventions and recovery planning. For fast-track VATS lobectomy, EPCA and IVPCA can both provide adequate, continuous, and comparably effective postoperative pain management. As fast-track, minimally invasive thoracic surgery has become an established technique in the management of pulmonary lesions, the planning of pain management should be retailored.