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© 2001 International Anesthesia Research Society
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Abstract |
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To assess the analgesic efficacy of patient-controlled bupivacaine wound instillation, 50 patients undergoing major intraabdominal surgery were enrolled into this prospective, placebo-controlled, double-blinded study. In all cases, a standard general anesthetic was administered. On completion of surgery, two multihole 20-gauge epidural catheters were tunneled through the proximal and distal apices of the surgical wound and placed above the fascia such that the tips were at the margin of the first and second thirds of the surgical wound, respectively. Postoperatively, a patient-controlled analgesia (PCA) device was connected to the instillation system. Either bupivacaine 0.25% (Bupivacaine Group) or an equal volume of sterile water (Control Group) was administered. The PCA device was programmed to deliver 9.0 mL with a 60-min lockout interval and no basal infusion. During the first six postoperative hours, a coinvestigator administered "rescue" morphine (2 mg IV). Thereafter, meperidine 1 mg/kg IM was administered on patient request for additional analgesia. Instillation attempts and actual number of injections were similar between the groups. The mean number of pump infusions and the mean "rescue" opioid requirements during the 24-h study period were similar between the groups. The total "rescue" morphine administered during the first six postoperative hours was 16 ± 17 mg vs 18 ± 14 mg for the Bupivacaine and Control Groups, respectively. The total meperidine administered during this period was 1.6 ± 1.4 mg/kg and 2 ± 1.2 mg/kg for the Bupivacaine and Control Groups, respectively. Preoperatively, hourly for the first six postoperative hours, and on removal of the instillation catheter, patient-generated visual analog scales for pain were similar at rest, on coughing, and after leg raise. In conclusion, bupivacaine wound instillation via an electronic PCA device and a double-catheter system does not decrease postoperative opioid requirements after surgery performed through a midline incision.
Implications: After major abdominal surgery performed through a 20-cm incision, repeated 0.25% bupivacaine wound instillation via an electronic patient-controlled analgesia device and a double-catheter system does not decrease postoperative pain or opioid requirements.
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Introduction |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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Patient-controlled local anesthetic wound instillation via an elastometric pump provides safe and effective postoperative analgesia after a variety of day-case operations (1). Similarly, after cesarean delivery performed through a Pfannenstiel incision, repeated ropivacaine instillation via an elastometric pump significantly decreased postoperative pain and opioid requirements (2). However, the analgesic efficacy of wound instillation after major abdominal surgery performed through a 20-cm midline incision is unknown. Furthermore, because of technical limitations, wound instillation via an elastometric pump may be unsuitable for more extensive inpatient surgery. Therefore, we modified the "classical" wound instillation system and performed a randomized, prospective, controlled, double-blinded study designed to assess the postoperative analgesic efficacy of bupivacaine wound instillation after major abdominal surgery performed through a 20-cm midline incision.
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Methods |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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Fifty ASA physical status I, II, III patients undergoing major intraabdominal surgery requiring a midline incision of
20 cm were enrolled into this IRB-approved, randomized, prospective, controlled, double-blinded study. Patients with a history of clinically significant cardiovascular, pulmonary, hepatic, renal, neurologic, psychiatric, or metabolic disease were excluded from the study. Patients with a history of chronic analgesic drug usage were also excluded from the study. All perioperative data were collected by a coinvestigator who was blinded as to the patient randomization. No preanesthetic medication was administered. Preoperatively, all patients were educated in the use of the patient-controlled analgesia (PCA) device. In the preanesthetic holding area, baseline 100-mm visual analog scales (VAS) (0 = minimal and 100 = maximal) were completed for pain, nausea, sleepiness, and anxiety.
On arrival in the operating room, monitoring equipment was applied and the following variables recorded at 1- to 5-min intervals throughout the operation: noninvasive blood pressure, electrocardiogram, and arterial hemoglobin oxygen saturation. Hemodynamic and anesthetic variables were recorded before anesthetic drug administration (baseline) and at 1-min intervals from the induction of anesthesia until 15 min after starting the procedure. Subsequent measurements were recorded at 3-min intervals until the end of the surgical procedure.
A standardized general anesthetic consisting of IV thiopental 3–5 mg/kg and fentanyl 7–10 µg/kg for the induction and 0.5%–1.5% isoflurane (end-tidal) and 70% nitrous oxide in oxygen for maintenance of anesthesia was administered. Tracheal intubation was facilitated by succinylcholine 1.0 mg/kg IV and surgical relaxation maintained (by using a peripheral nerve stimulator) with IV vecuronium. After the induction of anesthesia, end-tidal carbon dioxide concentration was monitored and the urinary bladder catheterized.
On completion of the operation, two multihole 20-gauge epidural catheters were tunneled by the surgeon 4–5 cm subcutaneously and secured on the skin by using a sterile tape. The catheters were placed above the fascia and lay along the length of the surgical wound. One catheter was tunneled through the proximal apex of the surgical incision. The second catheter was tunneled through the distal apex of the surgical incision. The wound was then divided into thirds (33%) and each catheter placed such that the catheter tip lay at the margin of the first and second third, respectively.
On arrival in the postanesthetic care unit (PACU), by using an aseptic technique, the catheter system was connected to a PCA device (GrasebyTM PCA Pump 3300, Graseby, Watford, Herts, UK). According to a computer generated randomization schedule the PCA device delivered either 0.25% bupivacaine (Bupivacaine Group) or water for injection (Control Group). In all cases, the PCA device was programmed to deliver 9.0 mL with a 60-min lockout interval and no basal infusion.
During the first 6 postoperative h "rescue" morphine 2 mg IV was administered by a coinvestigator who was blinded as to patient randomization. A VAS for pain >40 mm 20 min after initiating the PCA device constituted the trigger for "rescue" morphine administration. Thereafter, morphine 2 mg IV was administered at 10-min intervals until a pain score 
30 mm was recorded. Patients were discharged from the PACU 6 h postoperatively. After PACU discharge, meperidine 1 mg/kg IM was administered on patient request for additional analgesia.
An investigator blinded as to the study drug administered evaluated postoperative pain intensity at admission to the PACU, hourly for the first 6 postoperative h, and at 24 h postoperatively. At these time intervals, the following variables were recorded: PCA demands and actual instillations delivered; "rescue" analgesic drug requirements; and VAS for pain at rest, on coughing, and after a 20° leg raise, as well as for nausea, sleepiness, and anxiety.
Patients were interviewed 24 h postoperatively and (by using a scale of poor, satisfactory, good, or excellent) specifically asked to record their satisfaction with the analgesia provided. On completion of the postoperative interview, the catheters were removed, and the distal 5 cm was cultured for bacterial contamination. In addition, white blood cell count was monitored preoperatively and on the third postoperative day.
Prestudy power analysis determined a sample size of 25 patients per group to have a 80% chance (ß = 0.02) for detecting a 5-mg difference in "rescue" morphine requirements during the first 6 postoperative h at the 99% confidence interval limitations (
= 0.01) (2).
Data are expressed as mean values ± SD or SEM. In all cases, normality was assessed with the Kolmogorov-Smirnov test (by using the Lilliefors’ modification). Depending on the results of the Kolmogorov-Smirnov analysis, either parametric or nonparametric analysis was performed. Demographic and anesthetic data, as well as doses of drugs administered and white blood cell counts, were analyzed and compared by using the Student’s t-tests. Number of patients receiving "rescue" morphine, as well as patient satisfaction, was analyzed by using Fisher’s exact test or the 
2 test as appropriate. Patient-generated VAS was analyzed by using the Mann-Whitney U-test. P < 0.05 was considered statistically significant.
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Results |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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There were no differences between the groups with respect to age, weight, height, ASA physical status, length of surgical incision, and type of surgery (Table 1). Similarly, anesthetic time and surgery time, as well as PACU and hospital admission times, were comparable between the groups (Table 2). Intraoperative fentanyl administration was 8.7 ± 2.3 µg/kg vs 8.7 ± 2.7 µg/kg for the Bupivacaine and Control Groups, respectively.
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Instillation attempts and actual number of injections were similar between the groups (Fig. 1). The mean number of pump infusions during the 24-h study period were 13 ± 3 and 14 ± 4 for the Bupivacaine and Control Groups, respectively. During the first 6 postoperative h the number of patients requiring "rescue" morphine was similar between the groups. The total "rescue" morphine administered during the first 6 postoperative h was 16 ± 17 mg vs 18 ± 14 mg for the Bupivacaine and Control Groups, respectively (Table 3). During the 18 h after PACU discharge "rescue" meperidine was administered to 72% and 92% of patients in the Bupivacaine and Control Groups, respectively. The total meperidine administered during this period was 1.6 ± 1.4 mg/kg and 2 ± 1.2 mg/kg for the Bupivacaine and Control Groups, respectively (Table 3).
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Preoperatively, hourly for the first 6 postoperative h and on removal of the instillation catheter, patient-generated VAS for pain were similar at rest, on coughing, and after leg raise (Fig. 2). Throughout the study period, patient-generated VAS for nausea, sleepiness, and anxiety were unaffected by the treatment modality (Fig. 3).
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All patients stated that the PCA instillation system was easy to use. However, although patient satisfaction was unaffected by the randomization schedule, the majority of patients described their postoperative analgesia as satisfactory (Table 4).
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White blood cell counts before and after the study were similar between the groups. Finally, bacteriological culture of the catheter tip was negative in all cases.
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Discussion |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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Because of their analgesic properties and lack of opioid-induced adverse effects, local anesthetic drugs have become increasingly popular for treating surgical pain (3–6). However, as a result of their short duration of action and the consequent need for repeated drug administration, the widespread postoperative use of local anesthetic drugs has been limited. Despite these pharmacokinetic and pharmacodynamic limitations, local anesthetic wound instillation via an elastometric pump and indwelling catheter provides safe and effective analgesia after cesarean delivery and day-case procedures. However, in our opinion, technical considerations make this technique unsuitable after major inpatient surgery. First, because the elastometric pump is attached to a single instillation catheter and analgesia is dependent on local anesthetic spread, the length of the surgical incision will limit the efficacy of the local anesthetic-induced analgesia. Second, the central effects of residual anesthesia are greater in patients recovering from major surgery. Furthermore, opening and closing the pump clamp requires intact mental and psychomotor function. Therefore, local anesthetic toxicity may occur if, because of residual anesthesia, the patient accidentally fails to close the pump clamp and the entire volume of the balloon is delivered. To overcome these problems we have modified the classical wound instillation system. In an attempt to increase local anesthetic spread, the delivery device was connected via Y-connector to two instillation catheters that were placed within the surgical wound such that each catheter tip lay at a mark that demarcated the proximal and distal third of the surgical wound, respectively. In addition, because the electronic PCA device is easily programmed to deliver a predetermined volume and has a lockout time, after surgical procedures associated with delayed psychomotor recovery, this delivery system is likely safer than the elastometric pump.
The results of this study indicate that, in the volume and concentration administered, patient-controlled bupivacaine wound instillation does not decrease postoperative pain or opioid requirements after abdominal surgery performed through a 20-cm midline incision. This is supported by the fact that both objective indicators of pain intensity (number of patients requiring "rescue" morphine and actual morphine administration), as well as subjective pain assessment (patient-generated pain scores at rest and after coughing and leg raise), were not significantly improved in the Bupivacaine Group when compared with the Control Group. Furthermore, patient satisfaction with their postoperative analgesia was similar between the groups.
The failure to demonstrate bupivacaine-induced analgesia after major surgery is likely multifactorial. First, the factors determining the spread of the local anesthetic after wound instillation are unknown. Although our double-catheter system was designed to distribute local anesthetic evenly throughout the surgical wound, this assumption is difficult to verify. Second, when performing wound instillation, the ideal volume and drug concentration are likely dependent on the surgery performed. Therefore, after abdominal surgery performed through a 20-cm midline incision, it is possible that the volume of bupivacaine delivered after PCA activation was insufficient to achieve adequate analgesia. However, the PCA device (GrasebyTM PCA Pump 3300) used in this study has an infusion limit of 9.0 mL/activation. Furthermore, drug toxicity occurs in a dose-dependent manner. Because repeated local anesthetic administration is associated with systemic drug accumulation, a balance between therapeutic benefits of the local anesthetic administered and the associated toxic side effects must be sought (2).
Despite differences in dosage and volume of local anesthetic as well as surgical procedure, it is interesting to compare our results with those of previous investigations in which the analgesic efficacy of wound instillation was assessed. Although local anesthetic wound instillation via the elastometric pump is safe and effective after a variety of day-case procedures, a placebo-controlled, double-blinded study has not been performed (1). In contrast, in a randomized, placebo-controlled, double-blinded study designed to assess the analgesic efficacy of wound instillation after cesarean delivery, repeated ropivacaine (0.2%) instillation via an elastometric pump was associated with significant opioid sparing and improved patient comfort. Although toxic levels were not reached, systemic ropivacaine absorption occurred in a time-dependent manner (2). Furthermore, in a study performed by Horn et al. (7), ropivacaine infiltration followed by drain lavage (30 mL of a 7.5 mg/mL solution) significantly decreased postoperative pain and analgesic requirements after major shoulder surgery. However, in a study in which instillation catheters were placed between the muscle layer and peritoneum, bolus injections of bupivacaine 15 mL of a 2.5 mg/mL solution) did not decrease pain or analgesic requirements after abdominal hysterectomy performed through a Pfannenstiel incision (8).
We conclude that after major abdominal surgery performed through a 20-cm incision, repeated 0.25% bupivacaine wound instillation via an electronic PCA device (programmed to deliver 9.0 mL with a 60-min lockout interval and no basal infusion) and a double-catheter system does not decrease postoperative pain or opioid requirements. However, the efficacy of wound instillation by using alternate analgesic protocols requires further investigation.
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References |
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- Rawal N, Axelsson K, Hylander J, et al. Postoperative patient-controlled local anesthetic administration at home. Anesth Analg 1998; 86: 86–9.[Web of Science][Medline]
- Fredman B, Shapiro A, Zohar E, et al. The analgesic efficacy of patient controlled ropivacaine instillation following cesarean section. Anesth Analg. In press.
- Vater M, Wandless J. Caudal or dorsal nerve block? A comparison of two local anaesthetic techniques for postoperative analgesia following day case circumcision. Acta Anaesthesiol Scand 1985; 29: 175–9.[Web of Science][Medline]
- Brown AR, Weis R, Greenberg C, et al. Interscalene block for shoulder arthroscopy: comparison with general anesthesia. Arthroscopy 1993; 9: 295–300.[Web of Science][Medline]
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Malhotra V, Long CW, Meister MJ. Intercostal blocks with local infiltration anesthesia for extracorporeal shock wave lithotripsy. Anesth Analg 1987; 66: 85–8.
[Abstract/Free Full Text] -
Kehlet H, Dahl JB. The value of "multimodal" or "balanced analgesia" in postoperative pain management. Anesth Analg 1993; 77: 1048–56.
[Free Full Text] -
Horn E-P, Schroeder F, Wilhelm S, et al. Wound infiltration and drain lavage with ropivacaine after major shoulder surgery. Anesth Analg 1999; 89: 1461–6.
[Abstract/Free Full Text] - Kristensen BB, Christensen DS, Ostergaard M, et al. Lack of postoperative pain relief after hysterectomy using preperitoneally administered bupivacaine. Reg Anesth Pain Med 1999; 24: 576–80.[Web of Science][Medline]
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