|Year : 2018 | Volume
| Issue : 10 | Page : 759-764
Comparing epidural and wound infiltration analgesia for total abdominal hysterectomy: A randomised controlled study
Pooja Lal Ammianickal1, Chitra Rajeswari Thangaswamy1, Hemavathi Balachander1, Murali Subbaiah2, N C Pankaj Kumar1
1 Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
2 Department of Obstetric and Gynaecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
|Date of Web Publication||9-Oct-2018|
Dr. Chitra Rajeswari Thangaswamy
Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry
Source of Support: None, Conflict of Interest: None
Background and Aims: Continuous wound infiltration (CWI) is emerging as an alternative to continuous epidural infusion (CEI). This study compared postoperative pain scores of CEI with CWI in patients undergoing total abdominal hysterectomy (TAH). Methods: This prospective randomised controlled trial included 102 patients planned for TAH who were randomised into either Group E (CEI) or Group L (CWI). The catheter (epidural/wound infiltration) was inserted in Group E before induction) and Group L at the end of surgery. General anaesthesia was administered according to standard protocol. At the end of surgery, both groups received 10 mL bolus of 0.2% ropivacaine followed by infusion at 6 mL/h through the respective catheters. They also received intravenous patient-controlled analgesia with morphine. The primary outcome was the visual analogue score at rest (VASR) and at deep breathing (VASDB) post-operatively. Secondary outcomes were post-operative morphine consumption, side effects and patient satisfaction. Results: The mean VASR between two groups were comparable up to 8 h. Group E showed significantly reduced VASR compared to Group L at 12 h (2.32 ± 0.59 vs 2.62 ± 0.67, P = 0.019) and 24 h (2.30 ± 0.58 vs 2.62 ± 0.57, P = 0.006). Group E showed significantly reduced VASDB compared to Group L at 5 min and from 4 to 24 h. Total morphine consumption, side effects and patient satisfaction were comparable. Conclusion: We conclude that CEI is a superior analgesic technique compared to CWI in total abdominal hysterectomy in terms of reduced pain scores.
Keywords: Epidural analgesia, hysterectomy, infiltration anaesthesia, patient-controlled analgesia
|How to cite this article:|
Ammianickal PL, Thangaswamy CR, Balachander H, Subbaiah M, Kumar N C. Comparing epidural and wound infiltration analgesia for total abdominal hysterectomy: A randomised controlled study. Indian J Anaesth 2018;62:759-64
|How to cite this URL:|
Ammianickal PL, Thangaswamy CR, Balachander H, Subbaiah M, Kumar N C. Comparing epidural and wound infiltration analgesia for total abdominal hysterectomy: A randomised controlled study. Indian J Anaesth [serial online] 2018 [cited 2019 Oct 20];62:759-64. Available from: http://www.ijaweb.org/text.asp?2018/62/10/759/242876
| Introduction|| |
Pain after gynaecological surgeries is often undertreated as it is assumed to be associated with lower pain intensity. This under treatment of pain leads to patient dissatisfaction and other complications. The patient mobility, length of hospital stay and recovery can be hastened by using effective analgesic methods.,, Different modalities of pain management have been effectively used and compared with each other. Among these modalities, regional anaesthetic techniques have proven to be superior in providing satisfactory pain control.
While epidural infusion with local anaesthetics could provide adequate analgesia, it is also associated with complications such as hypotension, motor blockade, epidural haematoma and epidural abscess. Local wound infiltration catheter has been used frequently in the management of post-operative analgesia. It is found to be an effective method for early recovery of bowel function, reduced opioid consumption and home readiness. It has also been shown that wound infusion of local anaesthetics at the surgical site has an anti-inflammatory effect.
The continuous wound infiltration (CWI) catheter technique has been found to be effective in many surgeries including abdominal hysterectomy. Although the CWI catheter could be placed in several planes, we had planned to use it in the preperitoneal plane. If the preperitoneal plane CWI catheter technique could be proven as equally efficacious as epidural technique, it could be used as an alternative method in patients undergoing total abdominal hysterectomy (TAH) for post-operative analgesia. Hence, we designed this study to compare the analgesic efficacy of CWI with continuous epidural infusion (CEI) technique.
| Methods|| |
This study was conducted in a tertiary care teaching hospital over a period of 18 months. After obtaining Institute Ethics Committee approval and written informed consent from the patients, we included 106 patients aged 30–60 years belonging to the American Society of Anaesthesiologists physical Status 1 and 2. All participants were planned to undergo TAH through Pfannenstiel incision. Patients who had a history of allergy to local anaesthetics, contraindication to regional anaesthesia and surgical incision other than Pfannenstiel incision were excluded from our study.
Patients were recruited by convenient sampling method. They were randomized using computer-generated random numbers. Allocation concealment was done using serially numbered opaque-sealed envelope technique. The use of intravenous patient-controlled analgesia (PCA) was explained to all patients on the day before surgery. All patients were orally premedicated with tablets 20 mg famotidine, 10 mg metoclopramide and 5 mg diazepam on the morning of the surgery.
On the day of surgery, randomisation was done in the preoperative patient waiting area and explained about the procedure again. Then, patients were shifted inside the operating room. The electrocardiogram, pulse oximeter, non-invasive blood pressure, end-tidal carbon dioxide and temperature were monitored for all patients. After securing intravenous line, Ringer lactate was infused. In Group E, before induction of general anaesthesia (GA), an epidural catheter (Smiths Medical™ India Pvt Ltd) was inserted in L3–L4 level by standard technique. After ruling out the intravascular and intrathecal placement of the epidural catheter by a test dose (3 mL of 1.5% lignocaine with 5 μg/mL of adrenaline), GA was induced.
GA was administered to all the patients according to standard protocol. Morphine 0.1 mg/kg was administered intravenously (IV) 10 min before induction. GA was induced with thiopentone 5 mg/kg IV and muscle paralysis was achieved with vecuronium 0.1 mg/kg IV. After direct laryngoscopy, tracheal intubation was performed with an appropriate size endotracheal tube. Anaesthesia was maintained with oxygen in air and isoflurane. A bolus of 3 mg morphine was administered intravenously if analgesia was required.
Toward the end of the surgical procedure, in Group L, wound infiltration catheter (Pajunk Infiltra Long™, Medizintechnologie, Germany) was placed in the preperitoneal plane along the entire length of the wound by the gynaecologist. Wound infiltration catheter was placed in all patients after ensuring watertight closure of peritoneum. The catheter was fixed to the anterior abdominal wall using the fixation device provided with the set.
After skin closure, Group L received a bolus of 10 mL of ropivacaine 0.2% through the wound infiltration catheter followed by an infusion of 6 mL/h for 24 h. In Group E, 10 mL of 0.2% ropivacaine was given through the epidural catheter followed by an infusion of 6 mL/h for 24 h. Post-operatively, all patients were connected to intravenous PCA pump. The PCA was setup to deliver a bolus of 1 mg of morphine IV per actuation, lockout interval of 10 min and a 4 h limit of 10 mg of morphine.
Pulse rate, blood pressure and oxygen saturation were monitored every 5 min for the first 30 min, every 10 min for next 30 min and thereafter at 2, 4, 8, 12 and 24 h. The pain scores were assessed using the VAS at rest (VASR) and at deep breathing (VASDB) ranging from 0 to 10 (0 - no pain and 10 - worst pain ever) recorded in the immediate post-operative period and then at 1, 2, 4, 8, 12 and 24 h. The anaesthesiologist who was not involved in the intraoperative management only assessed the post-operative VAS score. The abdomen of the patient was covered to blind the observer. The infusion line was kept under the dress in such a way that the anaesthesiologist was able to see the infusion line emerging at the right shoulder in both the groups. Both VASR and VASDB were assessed by the same anaesthesiologist. The first request of PCA morphine and total 24 h morphine consumption was noted. The catheter was removed post-operatively at 24 h. The patient satisfaction score (assessed by Likert's score) at the end of 24 h and duration of hospital stay were noted. Post-operative complications such as nausea, vomiting (post-operative nausea and vomiting [PONV] assessed by PONV impact score), local complications such as bleeding and catheter displacement were all noted. Wound infection was noted by the gynecologist at the time of suture removal.
The primary outcome was to compare the visual analogue scale (VAS) scores at rest and deep breathing between the groups. The secondary aim was to compare the first request of analgesia, total post-operative morphine consumption, length of hospital stay, patient satisfaction and side effect profiles between these two analgesic methods.
The sample size was estimated using the statistical formula for comparing two independent means. The minimum expected mean difference in pain score at rest and deep breathing between the groups is 1.8 with a standard deviation (SD) of 2.7 and the sample size was estimated using 5% level of significance and 90% power. The sample size was 50 per group. The data obtained was subjected to standard statistical analysis using SPSS software version 22, IBM SPSS software base (SPSS South Asia Pvt., Ltd., Bengaluru, Karnataka, India). The demographic variables such as age, weight, height and body mass index were expressed as mean with SD The distribution of data on categorical variables such as PONV status and patient's satisfaction scale was expressed as frequency and percentages. The comparison of these variables between the groups was carried out using Chi-square or Fisher's exact test. The discrete/continuous variables such as pain score, the first request of analgesia and total post-operative morphine consumption were expressed as mean with SD The comparison of these variables between the groups was carried out using independent Student's t-test. All statistical analysis was carried out at 5% level of significance.
| Results|| |
A total of 106 patients were enrolled in this study. After excluding four patients, 102 patients were randomised into two groups. During the post-operative follow-up, one patient from each group was excluded from the study [Figure 1]. A total of 100 patients completed the study. There was no significant difference in the demographic profile between the two groups studied [Table 1].
The VASR scores were comparable between groups up to 8 h post-operatively. The VASR score was significantly less in Group E than Group L at 12 h (2.32 ± 0.59 vs 2.62 ± 0.67, P = 0.019) and 24 h (2.30 ± 0.58 vs. 2.62 ± 0.57, P = 0.006) [Table 2] The VASDB score was significantly less in Group E than Group L at 5 min and 4–24 h. At other time points, VASDB score was comparable [Table 3].
Both the groups had received only the initial bolus dose of morphine at the time of induction. No patient required any rescue dose of morphine. The time for the first request of PCA morphine bolus was comparable between Group E and Group L (42.60 ± 92.52 vs 37.80 ± 37.36 min, P = 0.734). The total post-operative morphine consumption was comparable between Group E and Group L (8.22 ± 3.98 vs 8.68 ± 3.86 mg, P = 0.558). The mean duration of hospital stay was 3.32 ± 0.51 day in Group E and 3.20 ± 0.40 days in Group L which was comparable (P = 0.197) [Table 4].
The mean blood pressure was significantly less in Group E than Group L from 30 min onward till 24 h. One patient from Group E was withdrawn from the study due to refractory hypotension. There was no catheter displacement in both groups which was noted at the time of removal of the catheter. There was a pericatheter leak in one patient in Group L who was excluded from further study. Comparison of patient satisfaction using Likert's score was comparable between the two groups. The incidence of PONV and wound complications were also comparable between the two groups [Table 4].
| Discussion|| |
In our study, we found that the mean VASR scores between the two groups of patients studied were comparable till 8 h. VASR score at 12 h and 24 h were significantly lower in Group E compared to Group L. Our methodology was similar to Bertoglio et al. in evaluating the efficacy of the wound infiltration catheter. Mean VAS scores at rest and coughing between the two groups were comparable at 2, 6, 12 and 24 h in their study. In contrast, our study had comparable VASR up to 8 h and VASDB up to 4 h. In addition, they had observed that the CWI provided superior analgesia compared to the epidural group at 48 h and 72 h after surgery whereas, in our study, CWI had inferior analgesia at 12 and 24 h. In their study, the superiority of the CWI could be due to continuous local anaesthetic inhibition of the local nociceptive pain receptors leading to superior blunting of the pain response. This may also be due to the fact that local anaesthetics have prolonged local anti-inflammatory effect which can contribute to improved pain scores with time. However, our study duration was only 24 h post-operatively which was the limitation.
Effective management of post-operative pain is a major concern in the perioperative management of patients undergoing abdominal surgeries. Continuous instillation of local anaesthetic into the wound has proven to be efficacious in providing analgesia in gynaecological surgeries. Local anaesthetic infiltration into the wound site has an anti-inflammatory response apart from blocking the painful nociceptive signals to provide effective longer lasting pain relief.
We found that the mean VASDB score at 5 min was significantly lower in Group E. It was comparable between Group E and Group L up to 2 h. Later from 4 to 24 h, patients in group E had a significantly lower mean VASDB scores compared to Group L. This could be due to lower volume of local anaesthetic infused per hour in the Group L. Previous studies showed no difference in the mean VAS scores on activity between epidural and CWI group. This could be due to the higher volume per hour infusion of the local anaesthetic in the CWI group. Bertoglio et al. had used an infusion rate of 10 mL/h of 0.2% ropivacaine in the wound infiltration group which is slightly higher than the infusion rate which we had used in our study. We planned to infuse the same infusion rate to both groups to eliminate observer bias. If we could have used 10 mL/h as previous studies, we could have observed better pain relief with CWI.
Post-operative pain after abdominal surgeries is contributed by sensitisation of nociceptive receptors in the abdominal wall. The major contribution of pain is from skin incision which is supplied by superficial pain receptors. However, blocking only these superficial receptors will not provide effective analgesia. Pain from deep muscle layers and peritoneum should also be taken care of. Hence, in our study, we decided to place the wound infiltration catheter in the preperitoneal layer. Two studies have demonstrated that preperitoneal infiltration of local anaesthetics has improved pain scores., Rackelboom et al. have compared patients undergoing caesarean section by infiltration of local anaesthetic below the transversalis fascia and above the fascia and found that wound infusion below the fascia is better on comparing morphine consumption and VAS score at rest. Few studies using wound infiltration placed subcutaneously have failed to provide any positive result.,
Wound infusion in preperitoneal layer will also take care of the visceral pain component to a certain extent. It was found that the somatic nociceptors can influence or modify the spinal component of visceral pain pathway. Hence, blockade of these receptors will automatically contribute to the blocking of the visceral pain component. Various radiological studies have shown that the drug deposited below the fascia remains deep providing blockade of local parietal and fascial nociceptors whereas, in subcutaneous plane, it spreads over the superficial layers sparing the deep layers.,
In our study, we compared the time for the first request of PCA morphine bolus after surgery between the two groups. We found that the time for the first request of PCA morphine bolus was 42.60 ± 92.52 min in Group E and 37.80 ± 37.36 min in Group L which was comparable. The total post-operative morphine consumption by the patients in the two groups studied was also comparable at the end of 24 h after surgery.
The PONV scores were also comparable between the two groups. We found that the mean duration of hospital stay was comparable. Thus, the time required for the patients to be ready for hospital discharge was similar in both the groups. We compared the patient satisfaction between the two groups of patients studied using the Likert scale. We found that the patients in both the groups were equally satisfied, and the results were comparable.
The limitation of our study was that the sensory level was not assessed as it may lead to observer bias due to segmental epidural analgesia. In addition, the anaesthesiologist could identify the presence of wound infiltration catheter fixed in the abdomen while testing for the sensory level. We need future research should be done on long-term follow-up and the impact of the analgesic technique on chronic pain conditions.
| Conclusion|| |
Continuous epidural analgesia is better than continuous wound infiltration catheter technique in terms of superior pain scores at rest and deep breathing.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]