Table of Content - Volume 16 Issue 3 - December 2020
Comparative study of dexmeditomedine and fentanyl as adjuvant to bupivacaine in spinal anaesthesia
Dhivya S1*, Dhakshinamoorthy M2, Sittaramane S3
1Pg Student, ²Professor, ³Assistant Professor, Department of Anaesthesiology, Rajah Muthaiah Medical College, Annamalai University, Chidambaram, Tamilnadu, INDIA. Email: dhivyavsm@gmail.com
Abstract Background: In this emerging anaesthesia , so many drugs like benzodiazepines, opioids , alpha agonist and many where used as an adjuvant to Bupivacaine in spinal anaesthesia , In this study dexmeditomedine which is an highly selective alpha 2 agonist and fentanyl are used as an adjuvant in intrathecal anaesthesia , The aim of this study is to evaluate intraoperative hemodynamic stablity , sedative effect, post operative duration of analgesia and side effects caused by fentanyl and dexmeditomedine Materials and Methods: In this study sixty patients who where randomly allocated in two groups as follows Group D: (n=30) thirty patients in this group receive 5mcg dexmeditomedine (0.5ml with non preservative normal saline ) with 15 mg (3cc) hyperbaric bupivacaine Group F: (n=30 ) thirty patients in this group receive 25 mcg fentanyl with 15 mg (3cc) hyperbaric bupivacaine Result: The thirty patients in Group D who received dexmeditomedine have prolonged sensory and motor block compared to patients received fentanyl , there is slower regression of sensory and motor in group D patients Conclusion: Thus in this study it is concluded that the patients received dexmeditomedine intrathecally have prolonged motor and sensory blockade and slower regression of spinal level and good intraoperative hemodynamic stablity and prolonged post operative analgesia compared to fentanyl. Key Words: Dexmeditomedine, Fentanyl, Hyperbaric bupivacaine , spinal anaesthesia
INTRODUCTION Spinal anaesthesia is the preferred technique for most of the lower abdomen and lower limb surgeries . It allows the patient to remain awake, minimize or completely avoid the problem associated with airway management. The technique is simple to perform as it reduces surgical stress and attenuates the increase in plasma catecholamine's and other hormones . Regional anaesthesia gives intra and post operative pain relief with full preservation of mental status and normal reflexes. with spinal anaesthesia , the onset of anaesthesia is more rapid and also provides post operative analgesia . post operative pain relief is a growing concern for an anaesthesiologist , as an uneventful post operative period makes surgery a comfortable proposition for surgical patients . : In this emerging anaesthesia , so many drugs like benzodiazepines, opioids , alpha agonist and many where used as an adjuvant to Bupivacaine in spinal anaesthesia The major issue in a lower abdominal surgery is when patient complains about pain either during handling the visceral organ or when there is no adequate analgesia given to the patients , Thus addition of fentanyl to hyperbaric bupivacaine improves the intraoperative analgesic effect of the patient and addition of dexmeditomedine to hyperbaric bupivacaine can improve the intraoperative sedative effect of the patient while maintaining the hemodynamic stablity of the patient and also addition of dexmeditomedine has prolonged post operative analgesia compared to other adjuvants.Dexmeditomedine is an good sedative drug used in intensive care unit in intubated patients and gives sedation and analgesic effect without disturbing the circadian rhythm of the patient
MATERIALS AND METHODS This study was conducted on sixty patients after getting ethical committee recognition , who where pre operatively assessed thoroughly regarding their physical status, General examination and systemic examination and pre operative investigations where assessed properly then patients categorsied in to American society of anaesthesiology 1 and 2 where taken for this study, All the patients where received T.Rantac 150 mg stat and T. diazepam 0.2mg/kg orally given , They where preloaded with intravenous fluid 10 to 15 ml/kg ringer lactate ,The inclusion criteria where patient between 18-50 years , presenting to lower abdominal and lower limb surgeries , exclusion criteria where patient with comorbities which are life threatening , uncontrolled diabetes or hypertensive then they where randomly allocated into two groups as follows GROUP D: (n=30) Thirty patients where given intrathecal 5 mcg dexmeditomedine (diluted in non preservative added normal saline )along with 15 mg hyperbaric bupivacaine (3cc) GROUP F: (n=30) In this group thirty patients where given 25mcg fentanyl along with 15 mg hyperbaric bupivacaine (3cc) Intrathecal injection was given in sitting position around 15 secs and then immediately after giving intrathecal injection patient was made to lie in supine position . Patient was carefully monitored and hypotension ie) 30% fall of systolic blood pressure from basal level is treated with inj ephedrine and adequate intravenous fluid replacement is done for hypotension , Bradycardia ie) fall in heart rate less than 50 is treated with inj . Atropine . 0.3 to 0.6 mg IV . Then further occurrence of symptoms such as nausea , vomiting, pruritis, respiratory depression are documented and treated symptomatically , oxygen 2 to 4 L/min is given in case there is fall in saturation to less than 90 %. Once the level is adequately reached surgeon is informed to start the surgery, Sensory level is checked by pin prick and motor level is assessed by modified bromage scale. The intra op monitoring regarding time of intrathecal injection to time taken to reach maximum sensory level and time of regression of sensory level beyond S1 is documented, and also hemodynamic status during intraoperative period and occurrence of any symptoms are recorded. During intraoperative period sedation was measured by modified ramsay sedation score which is as follows
Figure 1: RAMSAY sedation scale[14] Post operatively pain was monitored using visual analog scale (VAS ) . Hourly monitoring was done for first 2 hours followed by second houly monitoring for every four hours and then eighth hourly monitoring was done for next 24 hours . Intramuscular injection of diclofenac is given when VAS score reaches more than 5. Further case was followed up a week later for any symptoms of headache and dysasthesia.
Figure 2: VAS SCALE – 0- NO PAIN , 10- VERY SEVERE PAIN
RESULTS Regarding age , height , weight and ASA status patients where compared and there was no statistical significant difference in onset of motor and sensory block and there was no significant difference in duration taken to attain the highest level of sensory and motor level but in turn patients who where given intrathecal dexmeditomedine have slower regression of sensory level to S1 compared to patients given intrathecal fentanyl . The duration taken to reach highest sensory and motor level and time taken for regression of sensory and motor level are shown in the table below . There was no requirement of rescue analgesic in group D for first 24 hours compared to group F Table 1
Values given in above table are based on mean ±SD, ASA – American society of anaesthesiology , kg- kilograms , cm-centimeters , yrs –years , min -minutes
Types of surgery Table 2
Table 3
Eventhough hemodynamically both the groups where stable intra operatively , sedation score was more in group D patients , ie) the sedation score of group D patients where 4.0±2.0 and group F where 2.8±3.6, which is statistically significant .ie) P>0.05 There was no complications like nausea, vomiting, pruritis, respiratory depression in both groups and the requirement of vasopressor was more in group d compared to group f and one patient in group d had bradycardia (HR<50) which is managed by intravenous inj Atropine 0.3 mg and the following is the table regarding complications documented in both the groups.
Table 4
There was no neurological deficit or post dural puncture headache noted in any patients.
DISCUSSION Dexmeditomedine given intrathecally with local anaesthetic prolongs both motor and sensory block and this mechanism is not known clearly . By depression of release of C fibre transmitters and post synaptic dorsal horn neuron causing hyperpolarization results in analgesia .Synergesim occurring between local anaesthetics and alpha 2 adrenoceptor agonist may lead to prolongation of motor and sensory block . The antinociceptive action for visceral and somatic pain is due to intrathecal alpha 2 adrenoceptor agonist .Local anesthetic acts by sodium channel blocking effect. Fentanyl is a selective µ receptor agonist opioid , when given intrathecally it acts by binding with dorsal horn of spinal cord and shows supraspinal action and spread. There are so many animal studies where conducted with intrathecal dexmeditomedine dose ranging between 2.5 to 100 µgm and there was no neurological deficit recorded , In our study dose is decided based on numerous previous studies. In our study 5µg of dexmeditomedine added with intrathecal hyperbaric bupivacaine 15mg (3cc) and 25 µg of fentanyl added with hyperbaric bupivacaine 15mg (3cc) are compared each with thirty patients , the onset of sensory block , onset of motor block , heighest sensory level , heighest motor level where compared and all these where statistically insignificant as shown in the above table , ie) all where equal. The regression of sensory level and regression of motor level where slower in the dexmeditomedine added group compared to fentanyl group which were statistically significant . In conclusion addition of 5 µg dexmeditomedine is more effective than 25 µg fentanyl added intrathecally ie) dexmeditomedine group were intraoperatively hemodynamically stable , with minimal adverse effects and showed prolonged post operative analgesia adequate intra operative sedation which was more comfortable for patients.
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