Comparison of two different doses of Epidural Butorphanol in Lower Limb Orthopedic Surgery

Kujur S.¹, Kosam D.²

¹Dr. Shweta Kujur, Assistant Professor, Department of Anesthesiology and Critical Care, Chhattisgarh Institute of Medical Sciences, Bilaspur (C.G), ²Dr. Durga Kosam, Associate Professor, Department of Anesthesiology, Government Medical College, Rajnandgaon (C.G.) India.

Corresponding Author: Dr. Durga Kosam, Associate Professor, Department of Anesthesiology, Government Medical College, Rajnandgaon (C.G.) India. E-mail: kosamdurga@gmail.com

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Abstract

Introduction: Epidural and spinal anaesthesia both are effective alternative to general anaesthesia when surgical site is located in lower extremities. When post operative analgesia is required epidural anaesthesia is the choice. This study was conducted to assess the effect of Butorphanol added to local anaesthetic via epidural route and to optimize the dose of Butorphanol via epidural route i.e. 2mg and 3 mg and to observe the duration of postoperative analgesia with two different doses. Methodology: A randomized control study was conducted on 40 ASA I & II patients of either sex aged 18-60 yrs undergoing lower limb orthopedic surgery under epidural anesthesia. The patients were randomly allocated into two equal groups. Group A received 2 mg of Butorphanol along with local anaesthetic solution and Group B received 3mg of Butorphanol along with local anaesthetic. The onset and peak effect of sensoryand motor block, level of sedation, hemodynamic changes and duration of postoperative analgesia and complications, if any were observed. Results: For sensory effect, onset was 25±7.07 sec and peak effect 312.5±12.4 sec in Group A patients as compared to Group B where it was 12.81±21.68 sec and 162.8±21.68 sec respectively, which is statistically significant (P<0.05). For motor effect onset was 3.5±1.01 min and peak effect 11.4±3.91 min in Group A patients as compared to Group B patients where it was 2.7±0.67 min and 6.09±0.97 min (P<0.05). Hemodynamics remained stable and comparable in both the groups (P>0.05). Duration of postoperative analgesia according to VAS, pain relief in Group A patients was up to 8 hrs and in Group B it was up to 12 hours and rescue analgesia required only after 12hrs (P<0.05). Conclusion: Newer synthetic opioid- Butorphanol can be used along with local anaestheticsolution via epidural route in lower limb surgeries with effective intraoperative sedation and prolonged postoperative analgesia without fear of nausea/vomiting and respiratory depression.

Key words: Butorphanol, Epidural anesthesia, Local anesthetics, Orthopedic surgery

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Manuscript received: 27th September 2018 Reviewed: 7th October 2018 

Author Corrected: 15th October 2018 Accepted for Publication: 20th October 2018

Introduction

Epidural anaesthesia provides early postoperative mobilization and rehabilitation with minimal pain and discomfort. This advantage of epidural anaesthesia is needed in modern orthopedic surgery.

It has properties of central neuraxial blockade. It abolishes stress response to surgery, requires least manpower, reduced incidence of nausea and vomiting, decreased bleeding during sur­gery, deceased incidence of thrombo-embolic events and decrease use of postoperative analgesia [1].

Butorphanol, synthetic opioid is a strong k recep­tor agonist, a weak µreceptor agonist-antagonist and is relatively lipid soluble. It produces less respiratory depression and a reduced incidence of pruritus, nausea and vomiting which is a common phenomenon with morphine [2]. In this study we added Butorphanol to local anestheticsto assess the efficacy of Butorphanol and to optimize the dose ofButorphanol via epidural route i.e. 2 and 3 mg and toobserve the duration of postoperative analgesia with two different doses.

Methodology

This ran­domized prospective study was carried out at department of Anaesthesiology Chhattisgarh Institute of Medical Sciences, Bilaspur (C.G.). 40 patients of either sex, aged 18-60 yrs of ASA (American society of anesthesiologist) grade I or II undergoing lower limb orthopedic surgery were enrolled for study.

Exclusion criteria: Patients with history of drug abuse, respiratory and neurological disor­der, bleeding disorder, patients on MAO inhibitors were excluded from the study.

All patients were thoroughly examined during pre anaesthetic check up and investigated. Patients were randomly allocated to one of the following two groups in a double blind fashion based on a computer generated code. Group A received 2mg of injection Butorphenol along with local anaesthetic solution. Group B received 3mg of injection Butorphenol along with local anaesthetic solution .Patients were kept nil orally 8 hours prior to induction. In the operating room, monitoring devices were attached which included heart rate, electrocardiograph (ECG), pulse oximeter (SPO2), non invasive blood pressure (NIBP), respiratory rate. Baseline parameters were recorded, an intravenous line was secured and pre loading was done with Ringer lactate 10ml/kg.

Patients were administered epidural block with 18 gauge Touhy needle and catheter was secured 3-4 cm into the epidural space and test dose of 3ml of 2% Lignocaine hydrochloride solution containing adrenaline 1:200,000 was injected. After 4-6 minutes of administering the test dose epidural block was obtained with the local anaesthetic solution, which consisted of 20 ml of equal volume of Lignocaine 2% with Adrenaline (1:200,000) and injection Bupivacaine 5%. In group A along with local anaesthetic solution 2 mg of injection Butorphenol was added while in group B along with local anaesthetic solution 3mg of injection Butorphenol was added.

Patients were observed for onset (dull sensation to pin prick or decreased pain at injury site) and peak effect (no sensation felt) of sensory and motor block­ade, level of sedation (Table-1), time for maximum level achieved, duration of surgery and postoperative analge­sia. Top up dose was given after 1.5 hrs as half the initial dose. Sensory effect was observed at intervals of 30sec, 1, 3, 6,9,12 and 15 minutes after completing the drug injection. Sedation was graded as shown in (Table-1). For the motor effect Bromage's criteria [3] were used at intervals of 5, 10,15,20,30 minutes. Onset was consid­ered when there was grade 1 blockade and peak effect when the blockade was of grade 3.

Time for maximum level achieved was also noted. Patients were monitored for hemodynamics, RR and SpO₂ at 5, 10,15,30,60 minutes interval. Postoperatively patients were observed for pulse, B.P., VAS (visual ana­logue scale), analgesia score (Table 1) and complica­tions if any at intervals of 2, 4,6,8,10,12 hrs. The data was complied systematically and analyzed using Analysis of variance and chi –square test .To compare the continuous variables between two groups SPSS version was used.

Table-1: Scores for sedation, motor and analgesia

Sedation score

0 = No sedation.

1= Drowsy.

2= Asleep but arousable.

3= Asleep and not arousable.

Bromage's criteria

0 = No motor block.

1= Partial block, able to flex knees.

2- Acceptable, unable to flex knees.

3 = Unable to move legs.

Analgesia score (AS)

1 = No pain

2 = No pain at rest but duringvoluntary movement.

3= Pain at rest but tolerable

4= Intolerable pain

Results

In our study, the demographic data (Table-2) of the both groups were comparable (p>0.05).

 

Table-2:Demographic data.

Onset time for sensory effect (sec) in group A was 25±7.07; while in group B it was faster i.e.12.81±21.68 (p<0.05) (Table-3). Peak effect in group A was 312.5±12.4 sec, while in-group B it was 162.8±21.68 (sec) (p<0.05). For the motor blockade onset time (minutes) and peak effect in-group A was 3.5±1.01 and 11.4±3.91 respectively while in group B it was 2.7±0.67 and 6.09+0.97 (p<0.05). Thus, we observed faster onset as well as peak effect of both sensory and motor effect in group B patients as compared to group A patients.

Table- 3: Sensory and Motor Blockade

Table-4 shows the volume of drug (ml) required, time for maximum level of sensory blockade achieved (minutes), duration of surgery (hrs) and top up dose requirement in both the groups and they were compa­rable (P>0.05).

Table-4: Volume of drug and maximum sensory blockade

Table 5 shows sedation score. In group A 80% of patients and ingroup B 85% of patients had sedation score of 2 (asleep but arousable) (p>0.05).

Table- 5: Sedation Score

Graph 1 and 2 shows changes in pulse, sys­tolic blood pressure and diastolic blood pressure of both the groups and it was not significant. Respiratory parameters (Graph 3) shows that there was significant fall in respiratory rate in both the groups, but it was never <10/min (a sign for respiratory de­pression) (P<0.05). Reading on pulse-oximetry as shown in graph4 further supported this.

 

Evaluating the postoperative analgesia, according to visual analogue scale (graph 5), in group A 70% of patients had visual analogue scale of 3-5 up to 8 hrs and 30% of patients had visual analogue scale of 6-8. In group B 80% of patients had visual analogue scale of 3-5 up to 12hrs and 20% of patients had visual analogue scale of 6-8.

 

Discussion

Central neuraxial blockade is an important tool in the armamentarium of the anesthesiologists as the al­terations in physiology and biochemistry and thereby morbidity and mortality brought about by central neuraxial blockade are minimal as compared to general anaesthe­sia. Subarachnoid block is the most popular and widely practiced technique all over the world. But there has been resurgence of interest even in the epidural block­ade as it can be used alone or in combination with general anaesthesia and can be used for postoperative analgesia [1].

Opioids acting on spinal cord receptors provide dis­tinct advantage over its systemic administration like the quality of analgesia is better, sedation is less, function is preserved and outcome is improved. Side effects are no more frequent or severe as compared to systemic opio­ids required to produce equivalent analgesia [4].

For epidural anaesthesia, we have used com­bination of local anesthetics and opioid. Local anesthetics act by producing a reversible blockade of so­dium channels in nervous tissue preventing the trans­mission of electrical impulses and produce sympathetic blockade, while epidural opioids have their major site of action on pre- and post-synaptic receptors in the substantia gelatinosa of the dorsal horn producing se­lective block of nociceptive pathways. Studies have reported obtaining effective analgesia from the con­comitant use of Morphine-Bupivacaine and Fentanyl-Bupivacaine continuous epidural infusions. Another rational for these combinations is to reduce dosage of the individual agents with concomitant reduction in the incidence and severity of side effects[4]. Earlier studies have advocated routine combination of long and short acting local anesthetics together, as it significantly attenuated the 1-hour rebound increase in pain scores seen after short acting anaesthesia alone [5].