Evaluation of effect of adding dexmedetomidine to hyperbaric bupivacaine in spinal anaesthesia

Transcription

1 International Journal of Current Medical Research Vol. 4, No. 5, pp , May Full Length Research Article Evaluation of effect of adding dexmedetomidine to hyperbaric bupivacaine in spinal anaesthesia *,1Dr. Nazima Memon and 2 Dr. R. G.Pathak Department of Anaesthesiology, Dr. Shankarrao Chavan Government Medical College, Nanded, India Received 19 th April 2015; Published 31 st May 2015 Background and objectives: A number of adjuvants are added to local anaesthetic agents in spinal anaesthesia to increase the duration of the effects of local anaesthetic agents and improve the qualility of intraoperative and postoperative analgesia. Recently, Dexmedetomidine, the new highly selective alpha-2 agonist, is being used as adjuvant to local anaesthetic agent in spinal anaesthesia. The present study was designed to evaluate the effect of intrathecal dexmedetomidine on spinal anesthesia with 0.5% hyperbaric bupivacaine. Material and Methods: Eighty patients belonging to ASA Class I and II posted for lower abdominal surgeries. These Patient were randomly divided into 2 groups of 40 patients each: receiving 3 ml of hyperbaric bupivacaine plus 0.2ml normal saline and receiving 3ml of hyperbaric bupivacaine plus 0.2ml dexmedetomidine (10mcg diluted in ratio 1:2 with normal saline) Results: The duration of analgesia in was ± as compared to in which it was ± The difference was statistically significant (p <0.0001). Thus, Patient in receiving dexmedetomidine along with bupivacaine had prolonged effect not only intra operatively but extended into the postoperative period, reducing the requirement of rescue analgesics. Conclusion: Addition of dexmedetomidine to hyperbaric bupivacaine in spinal anaesthesia results in prolonged sensory and motor block, improves the quality of intraoperative as well as postoperative analgesia, with good hemodynamic stability and minimal side effects. Key words: Dexmedetomidine, Hyperbaric Bupivacaine, Spinal Anaesthesia. INTRODUCTION Spinal anaesthesia is most common regional anaesthesia technique used for below umbilical surgeries. Use of local anaesthetic agents alone is associated with a short period of sensory and motor blockade resulting in early demand of analgesics in postoperative period. To overcome this problem, a number of adjuvants from different pharmacologic classes have been studied and its effect on Spinal hyperbaric bupivacaine evaluated. Alpha (α)-2-adrenergic receptor agonists have provoked interest amongst anaesthetists for their sedative, analgesic, sympatholytic, anaesthetic sparing and haemodynamic-stabilizing operties (Anju Grewal, 2011). Dexmedetomidine, a highly selective α2- agonist with a relatively high ratio of α2/ α 1-activity (1620:1 as compared to 220:1 for clonidine), possesses all these properties without any significant reapiratory depression (Carollo et al., 2008; Hall et al., 2000). Making it a better and relatively safe adjunct in various clinical applications. *Corresponding author: Dr. Nazima Memon, Department of Anaesthesiology, Dr. Shankarrao Chavan Government Medical College, Nanded, India. Aims and Objectives To study effect of adding Dexmedetomidine to hyperbaric bupivacaine in spinal anaesthesia with respect to its effect on haemodynamics, prolongation of effect, quality of intraoperative and postoperative anaesthesia, sedation and incidence of complications if any. MATERIALS AND METHODS The study was carried out in a tertiary health care centre. A written and informed valid consent was obtained from all the patients. Inclusion criteria: ASA grade I & II Age years Either Sex, Male or female Elective Surgery Lower limb surgery lasting upto three hours. Exclusion Criteria ASA grade III, IV or V patients Hypotension. Patients Refusal

2 International Journal of Current Medical Research 356 Known Contraindication to spinal anaesthesia (Local infection, coagulopathy, pre-existing neurological disease) Emergency Surgery. Pregnant patient. Obese patient. All patients were examined a day before Surgery and were kept nil by mouth. Routine investigations like complete haemogram, Bleeding time, Clotting time, Kidney function tests, Liver function tests, Random blood sugar, Chest X-ray, ECG, HIV and HBsAg were done on all patients. All the patients received sedation night prior to Surgery. After taking patient inside operation theatre, intravenous line secured with 20 G venous cannula. Multipara monitor was attached. The monitoring parameters included Electrocardiography (ECG), Heart Rate, Systolic and Diastolic Blood pressure using Automated non invasive blood pressure monitoring, Respiratory rate (RR) and Oxygen saturation (S P O 2 ) which was done at a regular interval of 0, 1, 3, 5, 10, 20, 30, 45, 60, 75,90,1,120,135,150,165 and 180 minutes. Eighty patients of ASA I and II class were randomly allocated into two groups: : 40 patients receiving 3ml Hyperbaric bupivacaine + 0.2ml Normal Saline. : 40 patients receiving 3ml Hyperbaric bupivacaine + 0.2ml Dexmedetomidine (10mcg diluted in ratio 1:2 with normal saline). The study was double blind randomized controlled trial. The randomization was done by cards method picked up by a person not involved in the study. Both study person and patient were not aware of the drug administered. Spinal Anaesthesia was given in sitting position with 25G spinal needle in L 3 -L 4 interspace after which the patient was made supine. The sensory blockade was checked by 22G needle prick sensation at various dermatomes. postoperative analgesia using VAS score. Also the time noted as to when rescue analgesic i.e. intramuscular diclofenac was given. The sedation was assessed by Ramsay Sedation scale. (1 = Patient anxious, agitated or restless. 2 = Patient co-operative, oriented and tranquil alert. 3 = Patient responds to commands, 4 = Asleep but with brisk response to light glabellar tap or loud auditory stimulus, 5 = Asleep but with sluggish response to light glabellar tap or loud auditory stimulus, 6 = Asleep, no response) (Kiran Kumar et al., 2014). The incidence of complications like hypotension, bradycardia, nausea, vomiting, pruritis, urinary retention, respiratory depression etc was noted. Hypotension was considered as reading 30% less than preoperative level or systolic blood pressure less than 90mm Hg and Bradycardia was considered as Heart rate less than 60 and treated with intravenous atropine. Data was analyzed using statistical tests like chi square test and student s t test. The value of p<0. was considered statistically significant. OBSERVATION AND RESULTS The present study was carried out to study the effect of Dexmedetomidine as an additive to hyperbaric bupivacaine in spinal anaesthesia. A total of 80 patients undergoing elective lower limb surgeries under spinal anaesthesia were enrolled in our study. These patients were divided into 2 groups, namely. : 40 patients receiving 3ml Hyperbaric bupivacaine + 0.2ml Normal saline. : 40 patients receiving 3ml Hyperbaric bupivacaine + 0.2ml Dexmedetomidine (10mcg diluted in ratio 1:2 with normal saline) Sample size calculation was done using statistical software (Epi info software, version 6.04). Table 1. Demographic profile. (Values are mean ± SD ) p value Age (years) ± ± p = Not Significant Sex (male: female) 28:02 26:04 Height (cm) ± ± 5.10 p = 0.46 Not Significant ASA grading I:II 32:8 29: 11 Duration of surgery (min) ± ± p = 0.20 Not Significant Type of surgery: Surgery for vein Arthroscopy Tibia nailing Femur nailing Fracture patella Skin grafting Varicose The motor blockade was assessed by modified Bromage scale. (0 = Able to move the hip, knee and ankle, 1 = Unable to move the hip, but able to move the knee and ankle, 2 = Unable to move the hip and knee, but is able to move the ankle, 3 = Unable to move hip, knee and ankle) 10. The following parameters were noted: Onset of sensory blockade, Onset of motor blockade, Time to achieve maximum sensory level (minutes), Time for two segment regression (minutes) and intraoperative and The demographic profiles of both groups were comparable with respect to age, sex, height, ASA grading of the patient. The type and duration of surgery were also comparable (Table 1). In the present study, the following block parameters and observations were made as follows: (Table 2). Thus, addition of dexmedetomidine to hyperbaric bupivacaine in spinal anaesthesia leads to early onset of sensory block, prolonged duration of senory and motor blockade, prolonged postoperative

3 International Journal of Current Medical Research 357 Fig.1. Graph showing heart rate variation Fig. 2. Graph showing Variation in Systolic and Diastolic BP in and Fig. 3. Incidence of complications Table 2. Sedation Score (Ramsay Scale) Sedation Score analgesia and decreased requirement of analgesics in postoperative period. (as seen in Table 2). The hemodynamic profiles of both groups were studied. Fig 1 shows comparison of heart rate between two groups. Three patients in had bradycardia (Heart rate less than 60) and were treated with intravenous atropine 0.6mg. Similar effect was seen on Systolic and Diastolic blood pressure (Fig.2) There was a slight fall in both systolic and diastolic BP seen in as compared to. The fall in BP was managed by administration of crystalloids and one or two doses of IV Mephentermine 6 mg. The incidence of complications as seen in Fig 3 was noted. showed complications like bradycardia, hypotension but these were easily treatable with vigilant monitoring. Other complications like nausea, vomiting, pruritis, urinary retention and respiratory depression were not seen in both the groups. The maximum sedation score was 2 in majority of patients in, thus reducing anxiety of the patients. One of the patient in had sedation score 3, but it did not result in any complication. None of the patient in had sedation (Table 2). DISCUSSION Spinal Anaesthesia is most common regional anaesthesia technique used for lower limb surgeries. Local anaesthetic agent when used alone in spinal anaesthesia cannot meet the demand when surgery is prolonged and also in postoperative period. Various adjuvants have been tried for this purpose. Dexmedetomidine is a novel alpha- 2 agonist introduced recently and is being widely used as an adjuvant to local anaesthetic agent in spinal anaesthesia. Kalso et al reported that dexmedetomidine affinity to α 2 -adrenoceptor agonists is 10 times as compared to clonidine 4. As a neuraxial adjuvant - α2-ar

4 International Journal of Current Medical Research 358 agonists can activate a number of antinociceptive mechanisms depending on the dose; however, the main site for their antinociceptive effect in physiological pain conditions seems to be the spinal dorsal horn (Anju Grewal, 2011). given Bupivacaine 12.5mg with saline. 2 nd group 12.5mg Bupivacaine with 5µg Dexmedetomidine. 3 rd group 12.5mg Bupivacaine with 10µg Dexmedetomidine. He found that Dexmedetomidine has a dose dependent effect on the onset and regression of sensory and motor block The following were the main features of our study: (Values are mean ± SD) p value Significant/ Not Significant Onset of sensory block(min) 5.45 ± ± 0.37 p < Significant Time to achieve maximum block (min) ± ± 0.77 p < Significant Time of 2 segment regression from highest level (min) ± ± p < Significant Time of regression to S ± ± p < Significant Time of rescue analgesia(min) ± ± p < Significant Highest VAS Score 6.45 ± ± 0.53 p < Significant No. of doses of rescue analgesia (IM Diclofenac) in first 24 hrs ± ± 0.48 p < Significant Various doses of Dexmedetomidine are used in spinal anaesthesia, 3mcg, 5 mcg, 10 mcg and 15 mcg. Evidence indicates that neuraxial administration of dexmedetomidine produces spinal analgesia as efficiently as clonidine. Also Kalso et al 10 stated that subcutaneous atipamazole, a selective α-2 adrenoreceptor antagonist can reverse the effect produced by intrathecal dexmedetomidine. Dexmedetomidine has synergestic effect with local anaesthetic agents, as suggested by Salgado et al., They produce analgesia by depressing release of C-fiber transmitters and by hyperpolarization of post synaptic dorsal horn neurons. Thus both have dexmedetomidine and local anaesthetic have similar action with different mechanism (local anaesthetic agents block sodium channels), producing enhanced effect and prolongation of effect of spinal anaesthesia when given in combination intrathecally. Dexmedetomidine has gained popularity and it is replacing the use of intrathecal opioids which has a number of side effects like nausea, vomiting, pruritis, urinary retention, respiratory depression. The use of dexmedetomidine does not show this side effects. There are minimal changes in hemodynamics like bradycardia and hypotension which can be easily treated with good monitoring. The present study was designed to study the effect of dexmedetomidine when used as an additive to hyperbaric bupivacaine in spinal anaesthesia. The addition of dexmedetomidine increased the duration of hyperbaric bupivacaine in spinal anaesthesia to almost 2-3 times as compared to the use of hyperbaric bupivacaine alone. The duration of analgesia in was ± minutes and was ± minutes. The difference was statistically significant (p <0.0001). Thus the analgesia provided by addition of dexmedetomidine not only covered intraoperative period but also extended to postoperative period. The patients were painfree in postoperative period and demand of rescue analgesic in first 24 hours was much reduced. The quality of intraoperative anaesthesia as well as postoperative analgesia was better in study group (Group BD) than control group (). The VAS score was significantly reduced in than. (as shown in Table 2). Mahmoud M Al-Mustafa et al 1 and Hala EA Eid et al 8 studied the effect of Dexmedetomidine in different doses added to spinal isobaric Bupivacaine for Urological procedures. Sixty six patients were randomly assigned into 3 groups. 1 st group when used as an adjuvant to Bupivacaine in spinal anaesthesia. S.Chanda et al 13 compared the intrathecal dexmedetomidine, intrathecal clonidine and intrathecal normal saline added to hyperbaric bupivacaine, and found that dexmedetomidine was much more effective as an intrathecal additive to hyperbaric bupivacaine as compared to clonidine. This is because dexmedetomidine has more affinity for α2 receptors and is 8 to 10 times more potent than clonidine. Dinesh et al 5 showed prolongation of effect of hyperbaric bupivacaine used in spinal anaesthesia by intravenous administration of dexmedetomidine, which was probably due to its supraspinal action on locus ceruleus and dorsal raphe nucleus. Thus, Dexmedetomidine is used intrathecally as well as intravenously to prolong the effect of spinal anaesthesia with hyperbaric bupivacaine. Conclusion From the present study we conclude that use of dexmedetomidine as an adjuvant to hyperbaric bupivacaine in the dose of 10mcg provides a good alternative in prolonged surgery, avoiding general anaesthesia and also providing nearly 2-3 times to the analgesia provided by hyperbaric bupivacaine alone. The use of dexmedetomidine is associated with minimal haemodynamic changes and minimal sedation. REFERENCES Al Mustafa, M.M., Abu- Halaweh, S.A., Aloweidi, A.S., Murshidi, M.M., Ammari, B.A., Awward, Z.M, et al Effect of Dexmedetomidine added to spinal Bupivacaine for urological procedure. Saudi Med Journal., vol.30(3): Alka Shah, Ila Patel and Rachna Gandhi. Haemodynamic effects of intrathecal dexmedetomidine added to ropivacaine intraoperatively and for postoperative analgesia. International Journal of Basic and Clinical Pharmacology Volume 2; Issue 1.Page Anju Grewal Dexmedetomidine: new avenues. Journal of Anaesthesiology clinical pharmacology., 2011 Jul-Sep; 27(3): doi: / Carollo, D.S., Nossaman, B.D. and Ramadhyani, U Dexmedetomidine: A review of clinical applications. Curr Opin Anaesthesiol., 21:

5 International Journal of Current Medical Research 359 Chilkunda, N., Dinesh, N., A Sai Tej, Bevinaquddaiah Yatish, Vinayak, S., Pujari, R.M., Mohan Kumar, Chadalawada, V.R. and Mohan Effects of intravenous dexmedetomidine on hyperbaric bupivacaine spinal anaesthesia: A randomized study. Saudi journal of Anaesthesia., Volume 8, Issue-2, Page: Dr. Keshav Govind rao, Dr Manoj Kumar Chaurasiya, Dr Pawan Kumar and Dr. Aparna Shukla A randomized controlled double blind studyto compare dexmedetomidine 5 mcg and 10 mcg as an adjuvant to intrathecal bupivacaine. International journal of scientific research., vol 2, issue 12, dec 2013, pg Eisanach, J.C., De Kock, M. and Klimscha, W á2 adrenergic agonists for regional anesthesia. Anesthesiology., 85: Hala, E.A., Eid, Mohamed, A. and Shafie Dose related prolongation of hyperbaric bupivacaine spinal anaesthesia by dexmedetomidine. Ain Shams Journal of Anaesthesiology., 4 (2): Hall, J.E., Uhrich, T.D., Barney, J.A, Arain, S.A. and Ebert, T.J Sedative, amnestic, and analgesic properties of small-dose dexmedetomidine infusions. Anesth Analg., 90:699 7 Kalso, E.A., Poyhia, R. and Rosenberg, P.H Spinal antinociception by dexmedetomidine, a highly selective a2-adrenergic agonist. Pharmacol Toxicol. 68: Rajni Gupta, Jaishri Bogra, Reetu Verma, Monica Kohli, Jitendra Kumar Kushwaha, and Sanjiv Kumar Dexmedetomidine as an intrathecal adjuvant for postoperative analgesia Indian J Anaesth., 2011 Jul- Aug; 55(4): doi: / Kiran Kumar, S., Anand Kumar, C. and Murthy S.G.K A comparative, prospective, randomized Double blind study of the effect of IV Dexmedetomidine on subarachnoid block versus 0.9% Normal Saline as control. Scholars journal of Applied Medical Sciences. Sch. J. App.Med.Science., 2(5A); Salame Chanda, Bhure Anjali, Badawaik Gunjan, Marodkar Ketaki, Parate Sohal Comparative study of efficacy and safety of intrathecal dexmedetomidine versus intrathecal clonidine as an adjuvant with 0.5% hyperbaric bupivacaine total abdominal hysterectomy procedures. Journal of evolution of medical and dental sciences., vol 3; issue 16 Pg Salgado, P.F., Sabbaq, A.T., Silva, P.C., Brienze, S.L., Dalto, H.P., Modolo, N.S., Braz, J.R. and Nascimento, P Jr Synergestic effect between dexmedetomidine and 0.75% ropivacaine in epidural anaesthesia. Rev Assoc. Med Bras 2008; March-April 54(2); Vidhu Mahendru, Anurag Tiwari, Sunil Katyal, Anju Grewal, Rupinder Singh, M. and Roohi Katyal A comparison of intrathecal dexmedetomidine, clonidine and fentanyl as adjuvant to hyperbaric bupivacaine for lower limb surgery: A double blind controlled study. Journal of Anaesthesiology clinical pharmacology., Year 2013,volume 29, issue 4; pg *******