Comparison of Haemodynamic, block level and patient comfort by using 0.75% & 0.5% Hyperbaric Bupivacaine in Caesarean Section

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1 Original Article Comparison of Haemodynamic, block level and patient comfort by using.75% &.5% Hyperbaric Bupivacaine in Caesarean Section Objective: To compare the haemodynamic stability, level of block and patients comfort using 12 mg of.75% &.5% hyperbaric Bupivacaine in caesarean section. Study Design: A Randomized Control Trial Place and Duration of Study: Department of Anaesthesia, Mother and Child Health Center, PIMS from September 29 to December 29. Materials and Methods: Thirty patients for each group (Total 6) of ASA 1 & 11 aged between twenty to forty years, scheduled for Elective Caesarian Operation were included in this study. They were allocated groups randomly to.75% Bupivacaine hyperbaric or.5% Bupivacaine hyperbaric, 12 mg, by lumbar puncture using L3/4 space. All patients were not preloaded but had two 18 gauge IV cannula and co loading was done after giving SAB with lactated Ringers. Haemodynamics were noted two utes apart and level of block to cold was assessed after five ute of Sub arachnoid block. Need for rescue ephedrine, tachycardia, bradycardia, pain/uneasiness, nausea/vomiting and incidence of high spinal was noted. Total duration of surgery was also noted. Results: age was 28 years in both groups. weight was 71 kg in group 1 and 73 kg in group 2 (P=.175). Total duration of surgery was 64 utes in group 1 and 57 in group 2 (P=.85). There was no statistically significant difference between the haemodynamics of two groups. Six patients of group 2 had block level of T2 as compared to none from group 1 (P=.3). Rescue ephedrine was given to 17 patients from group 1 as compared to 9 patients from group 2 (P=.34). statistically significant tachycardia or bradycardia. Four patients from group 1 had pain and uneasiness during surgery (P=.5). Seven patients from group 1 had nausea and vomiting (P=.11). One patient from group 1 had high spinal while 4 patients from group 2 had high spinal (P=.353). Conclusion: There was no statistically significant difference but.5% Hyperbaric Bupivacaine is statistically superior in respect of need of rescue ephedrine, appropriate level of block for C Section and less incidence of nausea/ vomiting and pain/uneasiness adding to patient comfort during C Section. Key Words: Level of block, C Section, Bupivacaine. Rana Imran Sikander* Safder Ali** Shoaib Haider*** Malik Sheryar Khan**** Mohammad Hassan Farooq **** Mohammad Jameel**** Humaira Jadoon**** *Assistant Professor **Senior Registrar ***Associate Professor ****Postgraduate trainees Address for Correspondence: Dr. Rana Imran Sikander Assistant Professor In charge Anaesthetist MCH center Department of Anaesthesia ranaimransikander@hotmail.com Introduction Regional anaesthesia is associated with less maternal morbidity and mortality than general anaesthesia. 1 Hypotension and bradycardia are most common complications due to sympathetic block which is further worsened by aortocaval compression caused by gravid uterus. The incidence of hypotension and bradycardia are as high as 9%. 2 This hypotension and bradycardia is treated by giving intravenous fluids and reversing decreased systemic vascular resistance by different drugs. Ephedrine is vasopressor of choice in parturients as it maintains uteroplacental circulation. 3 Bupivacaine.75% hyperbaric and.5% isobaric are available in Pakistan since long and is most commonly used drug in regional anaesthesia. Currently.5% hyperbaric Bupivacaine is also available and is being used but no local publications are available. In this study we compared two different concentrations of Bupivacaine of same baricity, dose and injection site, using co loading technique in obstetric Ann. Pak. Inst. Med. Sci. 29; 5(4):

2 patients. We studied haemodynamics, level of block, patient comfort and complications in these two groups. As two different concentrations of Bupivacain are available in Pakistan, rationale of this study was to find out which concentration gives more haemodynamic stability, achieves adequate block for C Section with less complications, thereby adding to patients comfort. Materials and Methods This study was conducted from Sep 29 to Dec 29 in the department of Anaesthesiology, Mother and Child Heath Center, Pakistan Institute of M and & II, (3 for each group) aged 2-4, scheduled for elective Caesarean section were included in this study. These women were randomly assigned groups by lottery method. All emergency Caesarean sections, parturients with gestational diabetes and PIH, all diabetic and hypertensive patients, patients with valvular lesions and Coagulopathies were excluded from the study. After approval of hospital ethical committee and consent from patients, inclusion and exclusion criteria were met. Women were randomly assigned to groups 1 & 2 by lottery method. On arrival to Operation Theater, two large bored IV cannula (18G) were passed and attached with lactated Ringer s solution. Each patient was monitored with ECG, Pulse Oximeter and non invasive blood pressure. Baseline readings were recorded in lying position. Under aseptic measures lumber puncture was done in L3/4 space using 25 G Quincke Babcock cutting needle in sitting position. Bupivacain.75% hyperbaric 12 mg was given to group 1 and Bupivacain.5% hyperbaric 12 mg was given to group 2 at an injection rate of 1ml/1s. Patients were made to lie down immediately after injecting drug with 5-1 degree head down position and wedge under right hip to facilitate left lateral uterine displacement. Two lactated ringers solutions were opened to flow through 18G IV cannula at full flow immediately after giving SAB. Systolic pressure, diastolic pressure, Arterial Pressure (MAP) and heart rate were recorded at two ute interval for ten and later at 5. Level of block was assessed by using cold spirit swab after five utes as the drug gets fixed in 3-5 utes in SAB. Each patient had oxygen inhalation with face mask during the course of surgery. Patients whose systolic BP dropped below 9 or MAP less than 6 mm of Hg were given rescue ephedrine 3-5 mg IV. Increase in heart rate more than 2 % of base line was labeled as tachycardia and a similar drop was labeled as bradycardia. Patients were monitored for tachycardia, bradycardia, hypotension, nausea/vomiting, and uneasiness/pain through out the procedure. Total duration of procedure was also noted. All data collected were entered in a well structured Proforma. SPSS version1 was used to analyze the data. Age, weight, duration of surgery and haemodynamics were analyzed for mean and SD. T test was used to compare their means. Chi-Square test was used to analyze level of block, rescue ephedrine, tachycardia, bradycardia, pain/uneasiness, nausea/vomiting and high spinal. P value of.5 or less was considered to be statistically significant. Results In the year 28 total number of surgeries done were 543. Out of these 314 were Caesarean sections (8 elective and 2214 emergencies). 372 caesarean sections were done under GA (13%) while 2642 (87%) were done under regional anaesthesia (259 SAB-98% and 52 epidural-2%). age of the patients in group 1 was 28.4 with SD of 3.96 while in group 2 it was 28.7 with SD of Levenes test was applied and P=.844. Minimum age was 21 years and maximum age was 39 years. weight of patients in group 1 was 71.1 kg with SD of while in group 2 mean weight was 73.4 with SD of Levenes test showed P=.175. Minimum weight was 47 kg and maximum weight was 95 kg. Total duration of surgery in group 1 was 64 with SD of while in group 2 it was 57 with SD of Levenes test showed a P=.85. Minimum surgical time was 45 and maximum time was 13 table I. Table I: Correlation of age, weight and duration in the two groups (n=3) Variables Groups Std. P value Deviation Age in Group (years) Group Weight in Group ((Kg) Group Duration in Group (s) Group Baseline mean systolic BP was 129 with SD of in group 1 while it was 13 with SD of in group 2 (P=.664). systolic BP remained similar in the two groups table II. Table II: Correlation of haemodynamics in two groups (n=3) variable Groups Std. Deviation P value Systolic Group BP at Group Systolic Group Ann. Pak. Inst. Med. Sci. 29; 5(4):

3 BP at 4 Systolic BP at 1 BP at BP at 4 BP at Group Group Group Group Group Group Group Group Group Group Group Group Group Group Group Table III: Correlation of different variables (n=3 each group) Sr Variables Group I Group II P value 1 Level of block T2 T Need of rescue Ephedrine T6 Yes 3 Tachycardia Yes 4 Bradycardia Yes 5 Pain/ Yes Uneasiness 6 Nausea/ Yes Vomiting Level of block to cold table III at T2 was achieved in 6 patients in group 2 while T4 block was gained in 15 patients in group 1 and 19 in group patients from group 1and 5 patients from group 2 had T6 (P=.1). Rescue ephedrine (table III) was given to 17 patients from group 1 and 9 from group 2 (P=.34). Tachycardia (table III) was found in 12 patients from group 1 and 7 from group2 (P=.133). Four patients had event of bradycardia (table III) in group1 while only 3 had from group2 (P=.5). Four patients from group1 had pain and uneasiness (table III) during the course of surgery as compared to none from group2 (P=..5). Nausea and vomiting (table III) occurred in 7 patients from group1 while no patient experienced it from group2 (P=.5). One patient from group1 and 4 patients from group2 suffered higher blocks (P=.177). Discussion As we all know that multiple factors affect the physiology of SAB and it s very difficult to control these factors while comparing the two drugs. There is always some element of bias. In our study we tried our maximum to control these factors in order to reduce the bias but there are still some limitations of our study which I will discuss in cog paragraphs. Factors affecting the physiology of SAB are age of the patients and height of block. Again there is a list of factors which can affect the height of block like baricity, total dose, volume of drug, site of injection, speed of injection and patient s position. Do not forget that pregnancy is itself a physiological state which affect the height of block and may show unpredictable results. In our study we included young healthy parturients between 2-4 years of age. Weight is yet another factor which may affect the physiology of SAB. As age and weight are important factors affecting physiology of spinal anaesthesia so we included patients who were comparable in both respects as can be seen from our results (P=.844 and.175). All patients had same 5-1 degree head down and wedge under right hip. Nishikawa 4 and Desalu 5 showed that preloading with crystalloids does not prevent hypotension and prophylactic treatment with ephedrine is not a guarantee to prevent hypotension and bradycardia. We used co loading technique in which we pushed 5-1ml of crystalloid within ten after SAB and still if hypotension occurred; it was treated with 3-5mg of ephedrine. It was our conflicting finding that total dose of ephedrine never exceeded from 6mg contrary to Kee 1 who used 5mg of ephedrine. Yet in other studies imum dose of ephedrine was 3 mg but still there was significant incidence of hypotension contrary to our findings showing no incidence of hypotension after ephedrine and delivery of neonate. As speed of injection and site of injection may affect height of block, we used constant speed of 1ml/1s and L3/4 site in every patient. We also kept baricity constant as it may affect the height of block. 9 We used same dose i.e. 12mg of Bupivacaine in each patient but volume of injection can not be kept constant which was limitation of our study (1.6 ml for.75% and 2.4ml for.5%). In this study we found that parturients who were given.5% hyperbaric Bupivacaine experienced higher level of block as compared to those who received.75% hyperbaric Bupivacaine without adding to the complications (P=.1). Although we didn t find statistically significant difference between the haemodynamics of two groups but those who were given.75% hyperbaric Bupivacaine required more rescue ephedrine. Moreover there was statistically less incidence of nausea/vomiting and pain/uneasiness during C Section in parturients receiving.5% hyperbaric Bupivacaine (P=.5 and.5). Ann. Pak. Inst. Med. Sci. 29; 5(4):

4 Duration of surgery was also comparable as it is known to affect the pain or comfort during spinal anaesthesia. In order to see the effect of only concentration of hyperbaric Bupivacaine on haemodynamics and height of block we tried to keep constant all other factors that are known to affect the outcome like spinal needle, intervertebral space, baricity, speed of injection, patient position12,13. But as dose, volume and concentration of a drug has an inseparable relation and we kept the dose constant because dose is known to effect height of block more, so we had to vary the volume. The difference in volume was.8 cc that could affect the spread of intrathecal Bupivacaine but that was limitation of our study. Studies by Somboonviboon and Kyokong 11,14,15 showed that the incidence of hypotension and bradycardia is greater if analgesic level > or = T4 dermatome. But contradictory to our study although level of block was higher in parturients receiving.5% hyperbaric Bupivacaine but that higher block was not associated with higher incidence of hypotension and bradycardia in our study. Moreover rescue ephedrine was used more in.75% group and the comparative results were significant in this respect which indirectly indicates that these ladies developed more hypotension which is not explained by our results which showed no statistically significant haemodynamics at,2,4,6,8 and 1 utes in both the groups. One possible explanation of comparable haemodynamics is the use of ephedrine. Ephedrine was used only when ever there was hypotension. Over all incidence of hypotension was 43% (57% in.75% Group and 3% in.5% Group) which is far less as compared to Mercier. 2,16,17 The incidence of hypotension is significantly low in.5% group (P=.34). Duration of surgery was also comparable as it is known to affect the pain or comfort during spinal anaesthesia. In order to see the effect of only concentration of hyperbaric Bupivacaine on haemodynamics and height of block we tried to keep constant all other factors that are known to affect the outcome like spinal needle, intervertebral space, baricity, speed of injection, patient position. But as dose, volume and concentration of a drug has an inseparable relation and we kept the dose constant because dose is known to effect height of block more, so we had to vary the volume. The difference in volume was.8 cc that could affect the spread of intrathecal Bupivacaine but that was limitation of our study. Studies by Somboonviboon and Kyokong 11 showed that the incidence of hypotension and bradycardia is greater if analgesic level > or = T4 dermatome. But contradictory to our study although level of block was higher in parturients receiving.5% hyperbaric Bupivacaine but that higher block was not associated with higher incidence of hypotension and bradycardia in our study. Moreover rescue ephedrine was used more in.75% group and the comparative results were significant in this respect which indirectly indicates that these ladies developed more hypotension which is not explained by our results which showed no statistically significant haemodynamics at,2,4,6,8 and 1 utes in both the groups. One possible explanation of comparable haemodynamics is the use of ephedrine. Ephedrine was used only when ever there was hypotension. Over all incidence of hypotension was 43% (57% in.75% Group and 3% in.5% Group) which is far less as compared to Mercier. 2 The incidence of hypotension is significantly low in.5% group (P=.34). Conclusion There was no statistically significant difference but.5% Hyperbaric Bupivacaine is statistically superior in respect of need of rescue ephedrine, appropriate level of block for C Section and less incidence of nausea/ vomiting and pain/uneasiness adding to patient comfort during C Section. References 1. 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