Research and Opinion in Anesthesia & Intensive Care

ORIGINAL ARTICLE
Year
: 2015  |  Volume : 2  |  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

Correspondence Address:
Eslam N Nada
Moahada Street, El Hedaya Tower, El Sharkia, Zagazig, 44519
Egypt

Abstract

Background 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«SQ» 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. Results 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. Conclusion 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.



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 Jun 2 ];2:96-100
Available from: http://www.roaic.eg.net/text.asp?2015/2/4/96/178899


Full Text

 Introduction



Postoperative pain control after surgery, especially cardiac, thoracic, and abdominal, is important to reduce morbidity and hospital length of stay (LOS) [1].

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 [2],[3].

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 [4].

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 [5].

Variable results from wound irrigation using local anesthetics may result from the difference in the site of catheter placement and type of local anesthetic [6],[7]. 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 [8],[9].

It is well known that the maximum total dose of both bupivacaine and levobupivacaine per day is 5.5 mg/kg [10].

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.

Statistical analysis

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].{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].{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].{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].{Table 4}{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}

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].{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 [11],[12]. It also lowers hospital LOS [13].

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 [14],[15],[16],[17], with no incidence of increased wound complications. Moreover, a study by Rosenberg and Renkonen [18] 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) [16] after cardiac surgery, by Deneuvile et al. (1993) [17] after thoracotomy, and by Fredman et al. (2000) [14] after cesarean delivery.

In contrast, Trotter et al. (1991) [19] 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) [7] 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

None declared.

References

1Roberge CW, McEwen M. The effects of local anesthetics on postoperative pain. AORN J 1998; 68:1003-1012.
2Scott NB, Turfrey DJ, Ray DA, et al. A prospective randomized study of the potential benefits of thoracic epidural anesthesia and analgesia in patients undergoing coronary artery bypass grafting. Anesth Analg 2001; 93:523-525
3Gust R, Pecher S, Gust A, et al. Effect of patient-controlled analgesia on pulmonary complications after coronary artery bypass grafting. Crit Care Med 1999; 27:2314-2316.
4Mehta Y, Juneja R, Madhok H, et al. Lumbar versus thoracic epidural buprenorphine for postoperative analgesia following coronary artery bypass graft surgery. Acta Anaesthesiol Scand 1999; 43:388-393.
5Cheong W, Seow-Choen F, Eu K, et al. Randomized clinical trial of local bupivacaine perfusion versus parenteral morphine infusion for pain relief after laparotomy. Br J Surg 2001; 80:519-520.
6Vintar N, Pozlep G, Rawal N, et al. Incision self-administration of bupivacaine or ropivacaine provides effective analgesia after inguinal hernia repair. Can J Anaesth 2002; 49:481-486.
7Yndgaard S, Holst P, Bjerre-Jepsen K, et al. Subcutaneously versus subfascially administered lidocaine in pain treatment after inguinal herniotomy. Anesth Analg 1994; 79:324-327.
8Huang YF, Pryor ME, Mather LE, et al. Cardiovascular and central nervous system effects of intravenous levobupivacain and bupivacaine in sheep. Anesth Analg 1998; 86:797-804.
9McClellan KJ, Spencer CM Levobupivacaine. Drugs. 1998; 56:355-362.
10Cox. B, Durieux ME, Marcus MAE. Toxicity of local anesthetics. Best Pract Res Clin Anesthesiol 2003; 17:111-136.
11Hopf HW, Hunt TK, West JM, et al. Wound tissue oxygen tension predicts the risk of wound infection in surgical patients. Arch Surg 1997; 132:997-1004.
12Page GG, Blakely WP, Ben-Eliyahu S. Evidence that postoperative pain is a mediator of the tumor-promoting effects of surgery in rats. Pain 2001; 90:191-199.
13Gold BS, Kitz DS, Lecky JH, et al. Unanticipated admission to the hospital following ambulatory surgery.JAMA 1989; 262:3008-3010
14Fredman B, Shapiro A, Zohar E, et al. The analgesic efficacy of patient-controlled ropivacaine instillation after cesarean delivery. Anesth Analg 2000; 91:1436-1440.
15Klein S, Grant S, Greengrass R, et al. Interscalene brachial plexus block with a continuous catheter insertion system and a disposable infusion pump. Anesth Analg 2000; 91:1473-1478.
16Dowling R, Thielmeier K, Ghaly A, et al. Improved pain control after cardiac surgery: results of a randomized, double-blind, clinical trial. J Thorac Cardiovasc Surg 2003; 126:1271-1278.
17Deneuvile M, Bisserier A, Regnard J, et al. Continuous intercostal analgesia with 0.5% bupivacaine after thoracotomy: a randomized study. Ann Thorac Surg 1993; 55:381-385.
18Rosenberg H, Renkonen OV. Antimicrobial activity of bupivacaine and morphine. Anesthesiology 1985; 62:178-179.
19Trotter TN, Hayes-Gregson P, Robinson S, et al. Wound infiltration of local anaesthetic after lower segment Caesarean section. Anaesthesia 1991; 46:404-407.