|Year : 2015 | Volume
| Issue : 4 | Page : 96-100
Continuous regional local anesthetic infusion for pain control after median sternotomy
Eslam N Nada1, Heba M El Aasr1, Ahmed M Bakry2
1 Department of Anaesthesia and Intensive Care, Faculty of Medicine, Zagazig University, Zagazig, Egypt
2 Department of Cardiothoracic Surgery, Faculty of Medicine, Zagazig University, Zagazig, Egypt
|Date of Submission||03-Sep-2015|
|Date of Acceptance||22-Nov-2015|
|Date of Web Publication||17-Mar-2016|
Eslam N Nada
Moahada Street, El Hedaya Tower, El Sharkia, Zagazig, 44519
Source of Support: None, Conflict of Interest: None
The use of continuous wound irrigation by local anesthetics has attracted considerable attention in many surgical specialties, including cardiac surgeries. The aim of this study was to evaluate the postoperative analgesic effect of local anesthetic infusion into the wound resulting from a standard median sternotomy using a catheter of surgical vacuum device of size 12 Fr in patients after coronary artery bypass graft operation in comparison with intravenous analgesia.
Patients and methods
This is a randomized clinical study conducted in Zagazig University Hospital. After obtaining approval and written consent, 40 patients who were enrolled for coronary artery bypass graft with standard median sternotomy incision were divided into two groups: in group 1 postoperative pain was managed according to the ordinary protocol of the cardiac ICU - that is, intravenous pethidine 50 mg/12 h and 1 g paracetamol/8 h with supplemental doses of 25 mg pethidine on patients' demand, with the total daily dose of pethidine not exceeding 400 mg. In group 2 postoperative pain was managed by continuous regional local anesthetic infusion of bupivacaine 0.25% at a rate of 4 ml/h for 48 h by means of a catheter inserted over the sternum. The following data were collected: the amount and time of analgesia given to the patients, data from pain assessment carried out after extubation and every 4 h until discharge from the ICU, heart rate, systolic blood pressure, forced vital capacity (FVC), forced expiratory volume in the first second (FEV 1 ) and FEV 1 /FVC ratio, time of weaning from the mechanical ventilator, and time of discharge from the ICU and discharge from hospital.
There was significant statistical difference between the two groups regarding all of the collected data, except demographic data, FEV 1 /FVC ratio, and length of stay in the ICU, which was 48 h for all patients in both groups.
Continuous local anesthetic infusion after standard median sternotomy resulted in lower pain scores, less need for narcotics, rapid weaning from the mechanical ventilation, better respiratory functions, and shorter hospital length of stay.
Keywords: local anesthetic, median sternotomy, pain control, wound infusion
|How to cite this article:|
Nada EN, El Aasr HM, Bakry AM. Continuous regional local anesthetic infusion for pain control after median sternotomy. Res Opin Anesth Intensive Care 2015;2:96-100
|How to cite this URL:|
Nada EN, El Aasr HM, Bakry AM. Continuous regional local anesthetic infusion for pain control after median sternotomy. Res Opin Anesth Intensive Care [serial online] 2015 [cited 2020 Sep 29];2:96-100. Available from: http://www.roaic.eg.net/text.asp?2015/2/4/96/178899
| Introduction|| |
Postoperative pain control after surgery, especially cardiac, thoracic, and abdominal, is important to reduce morbidity and hospital length of stay (LOS) .
Pain control with systemic opioid analgesics is standard but with many side effects such as nausea, vomiting, constipation, pruritus, and respiratory depression that can result in unfavorable outcome and increase in hospital LOS and costs ,.
A thoracic epidural is advocated in patients who is undergoing a median sternotomy but the potential risk of some respiratory complications and risk for epidural hematoma in patients who require full anticoagulation has limited its role .
Several studies using continuous infusion of a long-acting local anesthetic at the operative site have shown improved outcome in many cases with respect to pain control, early ambulation, and reduced hospital LOS .
Variable results from wound irrigation using local anesthetics may result from the difference in the site of catheter placement and type of local anesthetic ,. Bupivacaine is the commonly used local anesthetic, but because of the risk for neurotoxicity and cardiotoxicity it can be replaced by levobupivacaine, which is almost equipotent with bupivacaine but with lower toxicity ,.
It is well known that the maximum total dose of both bupivacaine and levobupivacaine per day is 5.5 mg/kg .
The aim of this study was to evaluate the postoperative analgesic effect of local anesthetic infusion into the wound from a standard median sternotomy using a catheter of surgical vacuum device of size 12 Fr in patients after coronary artery bypass graft operation in comparison with intravenous analgesia.
| Patients and methods|| |
This study was a randomized clinical study conducted in Zagazig University Hospitals. After obtaining approval from the hospital ethics committee, written informed consent was taken from 40 patients who were enrolled for coronary artery bypass graft operations with standard median sternotomy incision. The patients were divided randomly using closed envelops into two groups: in group 1 postoperative pain was managed according to the ordinary protocol of the cardiac ICU using systemic analgesia and in group 2 postoperative pain was managed by continuous regional local anesthetic infusion using a catheter inserted over the sternum.
Exclusion criteria were as follows: ejection fraction less than 40%; presence of pulmonary diseases (abnormal pulmonary function tests conducted at baseline for each patient using a portable spirometer); renal insufficiencies (creatinine>2 mg/dl); congestive heart failure; liver disease (bilirubin above upper normal); allergy to any of the used anesthetics; inability to sign the consent form; and incidence of intraoperative or postoperative complications (hemorrhage, ischemia, or heart failure).
Every patient was given a detailed explanation of the study and was introduced to the pain Numeric Rating Scale (NRS), which ranged from 0 (no pain) to 10 (worst possible pain), 1-3 (mild pain), 4-6 (moderate pain), and 7-9 (severe pain).
Anesthetic management was standardized. Patients were medicated on call in the operative room with intravenous 0.03 mg/kg midazolam.
Anesthesia was induced with 7 μg/kg fentanyl, 2 mg/kg thiopental sodium, and rocuronium 1 mg/kg for intubation.
Anesthesia was maintained before and after bypass with propofol 3-6 mg/kg/h, isoflurane, and with fentanyl 1-2 μg/kg at the time of maximum surgical stimulation. Top-up doses of rocuronium 0.3 mg/kg were given every 30 min.
During bypass, propofol 6-12 mg/kg/h was used for maintenance of anesthesia with additional doses of fentanyl 100 μg, midazolam 5 mg, and rocuronium 25 mg at the start of bypass and on rewarming.
At the end of the operation in group 2 a surgical vacuum device catheter size 12 Fr was inserted over the sternum after wiring. The catheter tip was closed with transfixed silk sutures, which were helpful as a sure mark for whole-catheter removal later.
After catheter insertion it was tested by checking the free release of the loading local anesthetic from its side holes. The loading local anesthetic dose was 20 ml of marcaine 0.25%.
Local anesthetic infusion was started immediately after the loading dose by means of a syringe pump at a rate of 4 ml/h for 48 h with bupivacaine 0.25%. After 48 h the catheter was removed.
All patients in both groups received propofol sedation 1.5-6 mg/kg/h while on the mechanical ventilator (MV).
Pethidine 50 mg intravenously was given to all patients by the intensivist before awakening and extubation.
After extubation patients in group 1 were given intravenous pethidine 50 mg/12 h and paracetamol 1 g/8 h.
All patients in both groups had also received 25 mg pethidine intravenously on demand without exceeding the total daily dose of pethidine (400 mg/day).
The following data were collected for all patients
- Time of weaning from the MV after ICU admission.
- Time of discharge from the ICU and discharge from the hospital.
- The total amount of analgesic given to the patients either by the doctor or on patient demand along with any related complications.
- Pain assessment every 4 h after extubation and throughout the duration of ICU stay using NRS; the highest pain score for each patient was used for the statistical analysis. On the other hand, supplemental analgesia (25 mg pethidine) was given when pain score was greater than or equal to 4.
- Heart rate (HR) and systolic blood pressure (SBP), measured continuously in the ICU. These parameters were recorded at the same time as pain assessment and the highest readings for each patient were considered in the statistical analysis.
- Forced vital capacity (FVC), forced expiratory volume in the first second (FEV 1 ), and FEV 1 /FVC ratio, recorded as percentages of predicted normal values for the same age, sex, and height measured by means of a portable spirometer after extubation and repeated twice on the first and second days of ICU stay; the values were compared between the two groups each time.
The primary outcome of the study was postoperative pethidine requirement in group 2 compared with group 1. A sample size of 15 patients was needed in each group to achieve 80% power to detect 50% difference in postoperative pethidine consumption between the two groups. Twenty patients were included per group to replace any dropouts and to increase power on secondary outcomes.
Student's t-test and the χ2 -test were used, and data were expressed as mean values (X̄) ±SD or numbers and percentages, with P value less than 0.05 considered statistically significant.
| Results|| |
Considering demographic data there was no statistically significant difference between the two groups in terms of age, sex, weight, and height [Table 1].
Patient's HR and SBP showed significant difference between the two groups (P < 0.0001) and the highest HR and SBP of each patient were used in the statistics [Table 2].
The time of weaning from MV varied from 5 to 7 h in group 1 and from 3 to 5 h in group 2, with significant statistical difference (P < 0.0001) [Table 3].
The two groups showed significant difference in pain, as assessed by NRS (P < 0.0001); the pain score in group 1 ranged from 3 to 5 and in group 2 from 1 to 3. Also there was significant difference in total narcotic dosage on the first and second day of ICU stay (P < 0.0001); on the first day in group 1 the total dose of pethidine ranged from 175 to 200 mg but in group 2 it was only 50 mg. On the second day it ranged from 175 to 225 mg in group1, whereas patients in group 2 did not need any narcotic analgesic [Table 4] and [Table 5].
FEV 1 , FVC, and FEV 1 /FVC percentage of predicted based on American Thoracic Society criteria for restrictive lung disease, as measured by means of a spirometer, showed the following:
There was significant difference in FEV 1 and FVC between the two groups (P < 0.0001) but nonsignificant difference in FEV 1 /FVC ratio, all of whose values were normal, indicating restrictive pattern of pulmonary function.
Immediately after extubation FEV 1 and FVC were moderately severely reduced than predicted (<60% and ≥50%) in group 1, whereas in group 2 they were moderately (<70% and ≥60%) to mildly (<80% and ≥70%) reduced. After 24 h, FEV 1 and FVC ranged from moderately severe to mildly reduced than predicted in group 1, whereas in group 2 they improved to be mildly reduced or normal values. After 48 h in group 1 the pulmonary functions improved to be moderately or mildly reduced values than predicted but did not reach the normal values, whereas in group 2 they were mildly reduced or normal with increasing percentage of normal values [Table 6].
|Table 6: Pulmonary function tests (FEV1, FVC, and FEV1/FVC) measured immediately after extubation and then after 24 and 48 h (percentage of predicted normal values)|
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All patients remained for 48 h in the ICU.
Hospital LOS after discharge from the ICU showed significant difference (P < 0.0001) between group 1 (5-8 days) and group 2 (3-6 days) [Table 7].
| Discussion|| |
Postoperative pain relief is of considerable importance for patients psychologically and physiologically and it helps to prevent postoperative pulmonary complications from restricted respiration ,. It also lowers hospital LOS .
The use of continuous wound irrigation with local anesthetics has attracted the interest of many surgical specialties and can be used instead of epidural anesthetics in heart operations with standard median sternotomy ,,,, with no incidence of increased wound complications. Moreover, a study by Rosenberg and Renkonen  revealed an antimicrobial action of bupivacaine that leads to lower incidence of wound infection.
In our study we used the continuous wound irrigation technique with bupivacaine in comparison with intravenous narcotic administration using catheters of surgical vacuum devices and an ordinary syringe pump.
Our technique of local anesthetic irrigation or infusion resulted in good pain control and less narcotic use.
This result concurs with those of pain control studied by Dowling et al. (2003)  after cardiac surgery, by Deneuvile et al. (1993)  after thoracotomy, and by Fredman et al. (2000)  after cesarean delivery.
In contrast, Trotter et al. (1991)  failed to prevent pain after cesarean delivery by subcutaneous wound infiltration of bupivacaine. However, they used a single bolus dose, which is not comparable to the continuous infusion technique and they did not use subfascial infiltration, which was proved by Yndgaard et al. (1994)  to be more efficient than subcutaneous administration of local anesthetics.
Further, in our study, time of weaning from MV and hospital LOS were significantly decreased in group 2, which was concurrent with the decrease in pain scores. Similar results were observed for the pulmonary function tests, which were significantly better in group 2, as proper pain control as we mentioned before decreases postoperative pulmonary complications.
| Conclusion|| |
Continuous local anesthetic wound infusion after standard median sternotomy resulted in good pain control, less need for narcotics, rapid weaning from MV, better respiratory functions, and shorter hospital LOS. This was achieved by using an available wide-bore catheter the side holes of which covered the whole surgical incision.
| Acknowledgements|| |
Conflicts of interest
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]