INTRODUCTION:
Pain is one of the commonest and most unpleasant symptom that leads the patient to seek medical advice and whatever may be the cause it demands relief. Pain is a sensation which produces a reaction consisting of withdrawal response ,metabolic response, hormonal response and conscious aversion.
Pain has been defined by IASP [International association for study of pain] as an
unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage .The relief of post-operative pain is a subject which has been receiving an increasing amount of attention in the past few years.
Pain relief is necessary for 1.Humanitarian and 2. Therapeutic reasons. Pain relief must be 1.Effective 2.Safe 3.feasible Post operative pain relief is important in reducing the morbidity after surgery. Pain causes peripheral vasoconstriction, reduces functional residual capacity andsputum clearance.
Post operative pain relief has the following advantages-it can reduce the metabolic response to trauma, thus may prevent negative nitrogen balance. Moreover the pain relieved patient has better mobility with reduced incidence of chest infections and deep vein thrombosis. Patients with Hypertension and ischemic heart disease, when allowed to experience pain in the post operative period may develop a reactionary rise in blood pressure, tachycardia and may go for subendocardial ischemia, infarction, hence the need for post operative pain relief.
Spinal anaesthesia continues to be one of the commonest regional anaesthetic
techniques because of rapid onset, safety and simplicity. The use of neuraxial additive drugs with local anaesthetic agents has proved to exert synergistic action hence the various combinations have been tried.
Studies on tissue compatibility (eg.) CSF indicate that buprenorphine and Midazolammay safely be adminsiterd epidurally and intrathecally. The use of neuraxial additive drugs have shown that this method of Pain relief provide prolonged segmental analgesia without systemic side effects of narcotics or the sensory, motor or autonomic block seen with regional anaesthetic techniques for pain relief.
Since many Orthopaedic operations are performed frequently under sub arachnoid block it was decided to assess and compare the post-operative analgesia and side effects of buprenorphine and midazolam co-administered separately with subarachnoid anaesthetic agents like bupivacaine where longer duration of pain relief is required.
AIM OF THE STUDY:
To evaluate the Post –operative analgesic effects of Intrathecal Bupivacaine with
Buprenorphine and Intrathecal Bupivacaine with Midazolam following Orthopaedic Surgeries (lower limbs).
The parameters that were analysed are,
1. Duration of analgesia,
2. Quality and adequacy of analgesia as per the visual analog scale,
3. Effects of Drugs on Cardio-Respiratory and Central Nervous System,
4. Undesirable side effects like Motor Weakness, Urinary retention, nausea and
vomiting, Neurological dysfunction and allergic reaction(like pruritus).
MATERIALS AND METHODS:
The prospective clinical study was conducted at the Govt. Stanley Medical College Hospital, Chennai-1, in 75 adult patients undergoing elective Lower Limb Orthopaedic Surgery.
The hospital ethical committee approved this study and informed consent was obtained from each patient.
Study Design:
An open, randomised, comparative parallel group design was employed.
Inclusion criteria:
1. ASA 1 & II.
2. AGE 18-65.
3. Orthopaedic procedures of Lower Limbs.
Exclusion criteria:
1. ASA III & IV.
2. Bleeding diathesis.
3. Spinal Deformity.
4. Age 65 years.
5. CNS disorder.
6. Local anaesthetic sensitivity.
7. Local Sepsis.
SUMMARY:
A clinical study was undertaken to evaluate the efficacy, duration of pain relief and to know the quality of post-operative analgesia provided by neuraxial additives added to local anaesthetic agents.
The study was undertaken in 75 patients of ASA I and II posted for lower limb
orthopaedic surgery for post operative pain relief Group-A. 25 patients received only 3.0ml of hyperbaric 15mg (3ml) preservative free bupivacaine +0.4ml of 0.9% normal saline intrathecally.
Group B - 25 patients 3.0ml of 0.5% hyperbaric bupivacaine (Preservative free) +0.12 mg(0.4ml) of buprenorphine (Preservative free) given intrathecally.
Group C - 25 patients - 3.0ml of 0.5% hyperbaric bupivacaine (Preservative free) + 2mg (0.4ml) of Midazolam (Preservative free) given intrathecally.
The onset time of analgesia in all three groups was 2½ - 4 minutes. The highest level of analgesia in all three group was upto T6 level.
The motor blockade (Grade III) was upto three hours in these groups. The incidence of hypotension, bradycardia and pruitus were very low. The post-operative analgesia was upto 12 hours in Group B (S.D.59.46) and upto
6 hours in Group C (S.D.45.72).
Spinal buprenorphine is better than spinal midazolam in that it is useful for patients who require a longer period of pain relief in the Post-operative period and is not associated with significant Cardiovascular, Respiratory (or) Central Nervous system side effects.
Spinal opiate analgesia is better than parenteral opiates in that a smaller dose is
sufficient, thereby reducing the side effects and the patients are not unduly sedated and the duration of analgesia is much longer than the parenteral route thereby avoiding repeated injections.
Spinal opiates score over spinal local anaesthetics in that there is no motor block which is unwanted in post-operative patients. The sympathetic block they produce may result in hypotension and importantly the duration of action of spinal opiates is much longer than spinal local anaesthetics.
The best drug amongst the spinal opiates is yet to be defined. Most of the studies have been done with morphine which is a hydrophilic drug and a liphophilic drug like buprenorphine has a definite edge as better concentration are achieved in the spinal cord and very little is left in CSF curtailing its rostral spread and depression of vital centers.
The optimal dose for an intrathecal administration is lesser than the doses for epidural route.
The addition of buprenorphine to the local anaesthetic agent bupivacine has not
interfered with its action as for as duration of action, level of analgesia, the quality of the motor and sensory blockade (or) incidence of intra-operative complication like bradycardia, hypotension, nausea, vomiting etc. is considered.
A single intrathecal injection of buprenorphine with bupivacaine has produced not only a satisfactory anaesthesia but also a prolonged post operative analgesia upto 12 hours, thereby avoiding the repeated im or IV injections and also improving the morale of the patient.
Buprenorphine 0.12mg (Preservative free) with heavy bupivacaine 15mg (0.5%)
(Preservative free) is safe, cheap and provides good, and prolonged post operative analgesia without any significant side effects, compared to other available techniques. This correlates with the studies done by Sen Lipp M (1987).
CONCLUSION:
Buprenorphine 0.12mg (0.4 ml preservative free) with hyperbaric 0.5% bupivacaine 15mg (preservative free) given by intrathecal route is safe, cheap and provides good and prolonged postoperative analgesia without any significant side effects when compared to midazolam 2 mg (0.4 ml preservative free) with hyperbaric 0.5% bupivacaine 15mg (preservative free) given by intrathecal route. So this combination can be used for providing prolonged post-operative analgesia for lower
limb orthopaedic surgeries.
None of the patients had any respiratory depression, but few patients had nausea and vomiting in the intra and post-operative period which was not severe. Urinary Retention (8%) and Pruritus (4%) was reported in a small percentage of patients in Group B
