Efficacy of transdermal buprenorphine patch on post-operative pain relief after elective spinal instrumentation surgery.

BACKGROUND AND AIMS: Transdermal buprenorphine patch (TDB) is increasingly used for chronic pain management because of non-invasive dosing, longer duration of action and minimal side effects. However its role in acute post-operative pain management for spinal instrumentation surgery is not well established. The aim of this study was to evaluate the analgesic efficacy of buprenorphine patch for postoperative pain relief in patients undergoing spinal instrumentation surgery. METHODS: In this randomised, placebo-controlled, double-blinded, prospective study, 70 adult patients undergoing elective spinal instrumentation surgery were randomly allocated into two groups-TDB Group (buprenorphinepatch) and TDP Group (placebo patch). Time to first rescue analgesic requirement was the primary outcome. All patients also were monitored for total rescue analgesic requirement, drug-related adverse effect and haemodynamic status till 48 h after surgery. Statistical analysis was carried out using student independent t-test if normally distributed or with Mann-Whitney U-test if otherwise. RESULTS: Time to first post-operative rescue analgesic (tramadol) requirement was much delayed in TDB Group than TDP Group (708.0 ± 6.98 min vs 54 ± 0.68 min, P < 0.001) and the total tramadol requirement was higher in TDB Group (490.60 ± 63.09 averagevs. 162.93 ± 63.91 mg, P < 0.001). Intra-and post-operative haemodynamic status was also stable in TDB Group without any adverse event. CONCLUSION: A TDB patch (10 µg/hour) applied 24 hours before surgery can be used as a postoperative analgesic for lumber fixation surgery without any drug-related adverse effect.

Anaesthetic management of a child with large occipital meningomyelocele.

A meningomyelocele is herniation of meninges along with neural elements through a congenital defect in the cranium or vertebral column. Reported incidence of occipital meningomyelocele is 1 in 5000 live births. Children with meningomyelocele may have varying degrees of sensory and motor deficits and other important associated congenital defects with clinical features of brain stem compression. The major anaesthetic challenges associated with myelomeningocoele repair includes difficulty in securing airway, intra-operative prone positioning, accurate assessment of blood loss and prevention of hypothermia.

The effect of dexmedetomidine infusion on propofol requirement for maintenance of optimum depth of anaesthesia during elective spine surgery.

BACKGROUND: Maintenance of adequate depth of anaesthesia in spine surgery is vital to prevent awareness, to reduce stress response and possible autonomic instability frequently associated with spine surgery. Dexmedetomidine, a α2-adrenoceptor agonist with analgesic and sedative adjuvant property has been found to reduce dose requirement of multiple anaesthetic agents both for induction and during the maintenance of anaesthesia. AIM: The aim of this study is to observe the effect of dexmedetomidine, on the requirement of propofol for induction and maintenance of adequate depth of anaesthesia during spine surgery. METHODS: It was a prospective, randomised, double-blinded, parallel group, placebo controlled and open-lebel study in tertiary care hospital. A total of 70 patients aged 20-60 years, American Society of Anaesthesiologists GradeI and II, scheduled for elective spine surgery were randomly allocated into two groups. Each patient of Group D (n=35) received an initial loading dose of dexmedetomidine at 1 µg/kg over 10 min, started 15 min before induction of anaesthesia followed by an infusion at a rate of 0.2 µg/kg/h. Patients of Group P (n=35) received the same volume of 0.9% normal saline solution as placebo. Requirement of propofol at induction and during maintenance was calculated maintaining bispectral index between 40 and 60. P<0.05 was considered to be statistically significant. RESULTS: Mean requirement of propofol was found to be lessened by 48.08% and 61.87% for induction and maintenance of anaesthesia respectively while using dexmedetomidine. CONCLUSION: Administration of dexmedetomidine significantly reduces the requirement of propofol while maintaining desired depth of anaesthesia without any significant complication.

Anaesthetic management of a patient with motor neuron disease posted for microlaryngeal surgery.

Motor neuron disease (MND) typically affects upper and lower motor neurons without any sensory involvement. Regional anaesthesia is preferred in motor neuron disease patients to avoid aspiration and possibility of prolonged postoperative ventilation following general anaesthesia. As microlaryngeal surgery in a motor neuron disease patient needed airway protection, it was decided to perform the surgery under general anaesthesia with awake intubation following airway block and avoiding muscle relaxant agents completely to minimise unnecessary complications. The patient was allowed spontaneous breathing while maintaining anaesthesia and stable haemodynamic condition with combination of anaesthetic and analgesic agents accordingly throughout the operation.

A comparative study of duration of postoperative analgesia between epidural bupivacaine and epidural clonidine plus bupivacaine in lumbar laminectomy surgery under general anaesthesia.

A randomised prospective double-blind placebo controlled study was undertaken in 60 patients of ASA-I and II, scheduled for lumbar laminectomy under general anaesthesia using thiopentone, fentanyl, artracurium, N2O/O2 and isoflurane. After obtaining written Informed consent from all patients, they were randomly allocated to two equal groups ie, group A (n = 30) and group B (n = 30). Group A patients received clonidine 0.5 ml (75 microg) plus 5 ml 0.25% bupivacaine and group B patients received 5 ml 0.25% bupivacaine plus 0.5 ml of normal saline (NS) as a control through epidural route placed by the surgeon at the closure of the surgery. All the vital parameters were recorded at the time of epidural catheter placement and administering drugs and at 10 minutes interval thereafter till the patients were reversed with neostigmine and glycopyrrolate and then in the postanaesthetic care unit (PACU) at 15 minutes interval till the end of the study. All patients received injection diclofenac 75 mg IM as soon as they complained of pain or when the VAS score became > or = 4cm. The study ended when patients received injection diclofenac 75 mg IM as rescue analgesic. Any feature of motor block, sedation score and event of urinary retention were recorded in the PACU. Duration of postoperative analgesia was taken as the primary outcome and measured from the time of regaining full consciousness following surgery till receiving first injection of rescue analgesic in the PACU. Duration of postoperative analgesia was (546.36 +/- 11.55 minutes) in group A compared to (240.15 +/- 07.32 minutes) in group B. No clinically significant difference was found in heart rate, blood pressure, respiratory rate, oxygen saturation and motor blockade. Sedation score was slightly higher in group A, which was not significant. So small dose of clonidine (75 microg) as an adjuvant to 5 ml 0.25% bupivacaine in epidural route following lumbar laminectomy significantly prolonged postoperative analgesia and improved patient satisfaction without any clinically significant adverse reaction.

Peri-operative flexometallic endotracheal tube malfunction--an unusual complication.

Increased difficulty was encountered during manual ventilation following change of position from supine to prone in a patient intubated with a fresh flexometallic cuffed endotracheal tube, posted for elective lumbar discectomy. Prompt Identification of the problem was made and managed with replacement of the damaged tube with a new endotracheal tube in supine position. Following proper securing of the airway and repositioning of the patient, rest of the surgery and anaesthetic maintenance were uneventful. The cause of this unusual complication was ultimately found to be an obstruction along the length of lumen of the culprit endotracheal tube which was maximum at its proximal end by herniation of the deformed channel of the cuff with filled air generated due to backpressure from the tracheal cuff that might have been produced due to manufacturing defect.

Subdural pressure and brain condition during propofol vs isoflurane - nitrous oxide anaesthesia in patients undergoing elective supratentorial tumour surgery.

SUMMARY: Total intravenous anaesthesia has received much importance than inhalational anaesthesia in neuroanaesthetic practice. In an effort to determine whether any important clinical differences occur, studies concerning intracranial pressure (ICP), degree of dural tension and degree of brain swelling during intravenous and inhalational based anaesthesia are warranted like the present one. A total of 68 patients were assigned randomly to one of two groups. In Group-I(n=34), anaesthesia was induced with propofol (1-3mg.kg(-1)) and maintained with propofol (6-10mg.kg(-1).hr(-1)) and fentanyl (2-3mcg.kg(-1).hr(-1)). In Group-II (n=34), anaesthesia was induced with propofol (1-3mg.kg(-1)) but maintained with isoflurane, nitrous oxide and fentanyl (2-3mcg.kg(-1).hr(-1)). Moderate hypocapnia was applied to maintain arterial carbon dioxide around 30mmHg. Mean arterial blood pressure was stabilized with phenylephrine whenever necessary. Subdural intracranial pressure, mean arterial pressure, cerebral perfusion pressure were monitored before and after 10min period of hyperventilation. Furthermore, the tension of dura before and after of hyperventilation and the degree of brain swelling after opening of dura were also estimated by the neurosurgeon. No differences were found between the groups with regards to demographics, neuroradiologic diagnosis, position of head and time of ICP measurement. Before hyperventilation, both ICP and dural tension were significantly lower in Group I compared with Group-II (P<0.05). But after hyperventilation there was no significant difference of ICP and dural tension in between groups. The degree of brain swelling after opening of dura was similar in both groups. There was a positive correlation between measured ICP and brain swelling score.