Riya, - (2013) A Randomised Control Trial comparing Plain Ropivacaine with Ropivacaine mixed with Adjuvant Dexamethasone in Scalp Nerve Blocks in patients undergoing Supratentorial Craniotomy under General Anaesthesia. Masters thesis, Christian Medical College, Vellore.
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Abstract
INTRODUCTION: Anaesthesia for neurosurgical procedures entails a prudent balance of various factors that determine intracranial tension, cerebral metabolic rate and blood supply. The prolonged duration of meticulous surgical technique, need for placement of invasive arterial and central and venous catheters, requirement of sound knowledge of various pharmacodynamics properties of anaesthetic and non-anaesthetic drugs to manipulate intracranial pressure-volume relationships present an enormous challenge to the perioperative physician. The need for tailoring anaesthetic techniques to optimise monitoring of motor or sensory evoked potentials during surgery, cautious fluid management to minimise rise in intracranial blood volume while promptly replacing losses owing to osmotic agent-induced diuresis and blood loss as well as devising a strategy for post-operative pain management that balances optimal analgesia with minimal sedation, nausea and respiratory depression pose a tremendous task to the neuroanaesthesiologist involved in the perioperative care of the patient. The non-uniform distribution of pain fibres in the central nervous system causes large fluctuations in blood pressure and heart rate during intracranial surgery. Since pain experienced during craniotomy and in the postoperative period are due to a large extent from the scalp and the pericranial muscles, blocking the sensory nerve fibres supplying these could reduce the total anaesthetic requirement enabling early recovery. Scalp nerve block using local anaesthetics along with mild sedation is routinely used for awake craniotomy. This has also been studied as an adjunct for treatment of post-operative craniotomy pain and has been found to be effective in increasing the time interval between extubation and the first dose of post-operative rescue analgesic with lower pain scores similar to that of intravenous morphine. Many pharmacological agents have been added to local anaesthetics and their efficacy to prolong the duration of analgesia have been evaluated. In this dissertation we aspire to explore the role of adding dexamethasone as an adjuvant to local anaesthetic ropivacaine in pre-induction scalp nerve blocks in patients undergoing supratentorial craniotomy for space-occupying lesions under general anaesthesia. AIMS AND OBJECTIVES: AIMS: To study the effect of adding dexamethasone as adjuvant to local anaesthetic ropivacaine in scalp nerve blocks in patients undergoing supratentorial craniotomy under general anaesthesia. OBJECTIVES: 1. To compare duration of post-operative analgesia afforded by addition of dexamethasone as adjuvant to local anaesthetic ropivacaine in scalp nerve blocks with plain ropivacaine in patients undergoing supratentorial craniotomy 2. To evaluate the following parameters in the patients who receive plain ropivacaine in the scalp nerve block and those who receive ropivacaine as well as dexamethasone in the scalp block: • intra-operative anaesthetic requirement. • time to emergence from general anaesthesia, • incidence of post-operative nausea and vomiting. HYPOTHESIS: Addition of dexamethasone to ropivacaine in scalp nerve blocks given to patients undergoing supratentorial craniotomy under general anaesthesia prolongs the duration of post-operative analgesia, decreases intra-operative anaesthetic requirement, shortens time to emergence from general anaesthesia and decreases post-operative nausea and vomiting. MATERIALS AND METHODS: Settings: This study was carried out in the three neurosurgery operating theatres and neurosurgery intensive care unit of Christian Medical College and Hospital, Vellore, which is a two thousand bedded tertiary care hospital that caters to 90, 000 in-patients and 1.5 million outpatients annually. The twelve bedded neuro intensive care unit, four bedded neurotrauma ICU and ten bedded neuro high dependency unit (HDU) cater to the needs of pre-operative, post-operative and neurotrauma patients. Given the tremendous load of patients who need intensive care, these ICU‟s are equipped with state-of-the-art ventilators and monitors to adapt to the special needs of those who are critically ill. About 400 to 500 craniotomies are performed each year in our institution, of which more than 70% are supratentorial craniotomies. PATIENT SELECTION: Inclusion Criteria: 1. Adult patients (age more than 18 years) diagnosed with intracranial space-occupying lesions scheduled for elective supratentorial craniotomy. 2. ASA I to III. 3. Pre-operative GCS 15/15. Exclusion Criteria: 1. Patients who have undergone previous craniotomy, 2. Hypertensive patients on beta blockers, 3. Patients diagnosed with diabetes mellitus, 4. Pre-operative Glasgow Coma Scale (GCS) less than 15, 5. Pregnant patients, 6. Patients with known allergy to local anaesthetics, 7. Patients with peptic ulcer disease, 8. Patients with coagulopathy, 9. Patients with scalp infection, 10. Patients who refused to give consent to participate in the study. METHODOLOGY: The study recruited 90 consecutive patients who fulfilled the inclusion criteria between March 2012 and September 2012 after informed consent was obtained. The study protocol received approval from the Institutional Review Board and Ethics Committee of the Christian Medical College, Vellore, and was funded by the fluid research grant of the Christian Medical College. All patients were educated regarding the ten point Visual Analogue Scale (VAS) score the day prior to scheduled surgery. A score of zero indicated „no pain‟ while a score of ten implied „worst imaginable pain‟. A pre-op VAS score was determined for each patient recruited into the study using a sphygmomanometer inflated to 250 mmHg for 5 minutes, with patients asked to quantify the pain of the inflated cuff. On the day of surgery, patients were premedicated with oral diazepam and metoclopramide and wheeled into the operating theatre. RESULTS: A total of 90 patients were recruited in this study between March 2012 and September 2012, 45 patients in each Group. Group 1 patients received 0.2% ropivacaine with 8 mg dexamethasone in the scalp nerve block after induction of general anaesthesia and Group 2 patients received plain 0.2% ropivacaine in the scalp nerve block. Six out of 45 scalp blocks were inadequate to obtund heart rate and blood pressure response to cranial pins. Of these 6 failed blocks, 5 patients belonged to Group 2 and 1 patient to Group 1. Block duration could not be assessed in another 13 patients due to various reasons: 1 patient in Group 1 was not extubated, 1 patient in Group 2 had a post-op seizure, 1 patient in Group 2 underwent a re-craniotomy 4 hours post-op for raised ICP, 1 patient in Group 1 had features of raised ICP post-op and was conservatively managed and 9 patients (5 patients in Group 1 and 4 patients in Group 2) were inadvertently administered routine first dose analgesic on admission to the neuro-ICU without determining the VAS score. Hence, the block duration could be computed only for 38 (out of 45) patients in Group 1 and 33 (out of 45 patients) in Group 2. CONCLUSIONS: 1. Addition of 8 mg of dexamethasone to 0.2% ropivacaine in scalp nerve blocks performed after induction of general anaesthesia for patients undergoing supratentorial craniotomies for intra-cranial space-occupying lesions does not prolong the duration of the scalp nerve block when compared to using plain 0.2% ropivacaine in the block. 2. Intra-operative fentanyl requirements appear similar in patients who received ropivacaine with dexamethasone in the scalp nerve block compared to those who received plain ropivacaine. 3. Intra-operative propofol requirements were significantly greater in patients who received dexamethasone in the scalp nerve block when compared to those who received plain ropivacaine. 4. There was no difference in the time to emergence from general anaesthesia between patients who received dexamethasone as adjuvant to ropivacaine in the scalp nerve block when compared to those who did not. 5. There was no difference in the incidence of post-operative nausea and vomiting between the patients who received dexamethasone as adjuvant in the scalp nerve block and those who received plain ropivacaine in the block. 6. There is no significant difference in the median VAS score prior to administration of first rescue analgesic between the two groups. 7. There was no significant correlation between a higher pre-op VAS as estimated with a sphygmomanometer inflated to 250 mmHg for 5 minutes and a shorter block duration across both groups of patients. 8. There was a statistically significant association between failed scalp blocks and temporal site of craniotomy in patients in whom plain 0.2% ropivacaine was used in the scalp nerve block. 9. There was no significant association between failed scalp nerve blocks and higher patient weight in both groups of patients. 10. There was no major complication associated with addition of dexamethasone as adjuvant to scalp nerve block.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Plain Ropivacaine ; Ropivacaine ; Adjuvant Dexamethasone ; Scalp Nerve Blocks ; patients ; undergoing Supratentorial Craniotomy ; General Anaesthesia ; Randomised Control trial. |
| Subjects: | MEDICAL > Anaesthesiology |
| Depositing User: | Subramani R |
| Date Deposited: | 30 Apr 2018 02:55 |
| Last Modified: | 30 Apr 2018 02:55 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/7336 |
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