Isobaric Bupivacaine Research Articles

Hyperbaric Versus Isobaric Bupivacaine for Spinal Anesthesia: Systematic Review and Meta-analysis for Adult Patients Undergoing Noncesarean Delivery Surgery

It is widely believed that the choice between isobaric bupivacaine and hyperbaric bupivacaine formulations alters the block characteristics for the conduct of surgery under spinal anesthesia. The aim of this study was to systematically review the comparative evidence regarding the effectiveness and safety of the 2 formulations when used for spinal anesthesia for adult noncesarean delivery surgery. Key electronic databases were searched for randomized controlled trials, excluding cesarean delivery surgeries under spinal anesthesia, without any language or date restrictions. The primary outcome measure for this review was the failure of spinal anesthesia. Two independent reviewers selected the studies and extracted the data. Results were expressed as relative risk (RR) or mean differences (MDs) with 95% confidence intervals (CIs). Seven hundred fifty-one studies were identified between 1946 and 2016. After screening, there were 16 randomized controlled clinical trials, including 724 participants, that provided data for the meta-analysis. The methodological reporting of most studies was poor, and appropriate judgment of their individual risk of bias elements was not possible. There was no difference between the 2 drugs regarding the need for conversion to general anesthesia (RR, 0.60; 95% CI, 0.08-4.41; P = .62; I = 0%), incidence of hypotension (RR, 1.15; 95% CI, 0.69-1.92; P = .58; I = 0%), nausea/vomiting (RR, 0.29; 95% CI, 0.06-1.32; P = .11; I = 7%), or onset of sensory block (MD = 1.7 minutes; 95% CI, -3.5 to 0.1; P = .07; I = 0%). The onset of motor block (MD = 4.6 minutes; 95% CI, 7.5-1.7; P = .002; I = 78%) was significantly faster with hyperbaric bupivacaine. Conversely, the duration of motor (MD = 45.2 minutes; 95% CI, 66.3-24.2; P < .001; I = 87%) and sensory (MD = 29.4 minutes; 95% CI, 15.5-43.3; P < .001; I = 73%) block was longer with isobaric bupivacaine. Both hyperbaric bupivacaine and isobaric bupivacaine provided effective anesthesia with no difference in the failure rate or adverse effects. The hyperbaric formulation allows for a relatively rapid motor block onset, with shorter duration of motor and sensory block. The isobaric formulation has a slower onset and provides a longer duration of both sensory and motor block. Nevertheless, the small sample size and high heterogeneity involving these outcomes suggest that all the results should be treated with caution.

Hyperbaric vs. isobaric bupivacaine for spinal anaesthesia for elective caesarean section: a Cochrane systematic review.

Both isobaric and hyperbaric bupivacaine have been used for spinal anaesthesia for elective caesarean section, but it is not clear if one is better than the other. The primary objective of this systematic review was to determine the effectiveness and safety of hyperbaric bupivacaine compared with isobaric bupivacaine administered during spinal anaesthesia for elective caesarean section. We included 10 studies with 614 subjects in the analysis. There was no evidence of differences either in the risk of conversion to general anaesthesia, with a relative risk (95%CI) of 0.33 (0.09-1.17) (very low quality of evidence), or in the need for supplemental analgesia, the relative risk (95%CI) being 0.61 (0.26-1.41) (very low quality of evidence). There was also no evidence of a difference in the use of ephedrine, the amount of ephedrine used, nausea and vomiting, or headache. Hyperbaric bupivacaine took less time to reach a sensory block height of T4, with a mean difference (95%CI) of -1.06 min (-1.80 to -0.31). Due to the rarity of some outcomes, dose variability, use of adjuvant drugs and spinal technique used, future clinical trials should look into using adequate sample size to investigate the primary outcome of the need for supplemental analgesia.

Spinal Anesthesia for Hip Fracture Surgery in an Elderly Patient with Acute Hypertensive Lung Edema

Background: Nowadays, fracture surgery represents a big part of the orthopedic surgeon workload, and usually has associated major clinical and social cost implications. We report a patient case of hip fracture with acute pulmonary edema treated with inguinal lumbar plexus block for analgesia and spinal anesthesia with low dose of isobaric bupivacaine for surgery. Case Report: A 85-year-old female was admitted with fracture of the hip. Echocardiography was performed, which found respiratory auscultation with crepitates rules in both lungs, associated with blood pressure of 205x 108 mmHg. Chest radiographs showed a bilateral alveolar infiltrate. After discussion with the surgical team and family members, previous analgesia was proposed for lumbar plexus block via inguinal and spinal anesthesia with low dose of isobaric bupivacaine. The surgery lasted 110 min. In the PACU, the vital signs were blood pressure 140x73 mmHg, heart rate 80 bpm and with 98% oxygen saturation in the nasal catheter, and diuresis of 2,400 mL, as well as cardiac enzymes are normal. Received 200 mL of a drink with high energy and transferred to infirmary. The patient was discharged to her home on the third postoperative day asymptomatic. Conclusions: The most important fact of this case is that the 85-years old patient with acute lung edema improved considerably after lumbar plexus block and spinal anesthesia with low doses and returned to her home on the third postoperative day.

Continuous femoral nerve blockade and single-shot sciatic nerve block promotes better analgesia and lower bleeding for total knee arthroplasty compared to intrathecal morphine: a randomized trial

BackgroundKnee arthroplasty leads to postoperative pain. This study compares analgesia and postoperative bleeding achieved by intrathecal morphine with a continuous femoral plus single-shot sciatic nerve block.MethodsA randomized non-blinded clinical trial enrolled patients aged over 18 years old, ASA I to III who underwent total knee arthroplasty. All patients underwent spinal anesthesia with isobaric bupivacaine, 20 mg. One group received 100 mcg of intrathecal morphine (M group), and the other received a femoral nerve block by continuous infusion plus a "single shot" block of the sciatic nerve at the end of the surgery (FI group). Pain score from verbal numeric rating scale (VNRS) and morphine consumption during the first 72 h, as well as motor blockade, adverse effects, and postoperative bleeding were recorded. Analysis of variance of repeated measures with Bonferroni post-test, t-test and Fisher exact test were used for statistical analysis.ResultsThirty nine patients completed the study (M = 20; FI = 19 patients) and were similar except for higher age in the FI group. Motor blockade as well as movement pain during postanesthesia care unit (PACU) staying were not different between the groups, but movement pain was significantly lower in FI group after 24 h. Postoperative bleeding (ml) was lower in FI group.ConclusionsContinuous femoral nerve block combined with sciatic nerve block provides effective for postoperative analgesia in patients undergoing total knee arthroplasty, with lower pain scores after 24 h and a lower incidence of adverse effects and bleeding compared to intrathecal morphine.Trial registrationRetrospectively registered on https://clinicaltrials.gov/ under identifier NCT02882152, 23rd December, 2016.

The improved quality of postoperative analgesia after intrathecal morphine does not result in improved recovery and quality of life in the first 6 months after orthopedic surgery: a randomized controlled pilot study.

ObjectiveIn orthopedic surgery, it is well known that the use of intrathecal morphine (ITM) leads to an improved quality of postoperative analgesia. Little is known how this improved analgesia affects the long-term course after surgery.Study designA randomized, double-blind trial.SettingAcademic medical center.SubjectsForty-nine patients undergoing total hip or knee replacement surgery in spinal anesthesia.MethodsPatients were randomly assigned to receive either 0.1 mg (n=16) or 0.2 mg (n=16) morphine sulfate intrathecally or physiological saline (n=17) added to 3 mL 0.5% isobaric bupivacaine for spinal anesthesia. As a function of the quality of the short-term postoperative analgesia, the effect on recovery and quality of life was evaluated at various time points up to 26 weeks after surgery.ResultsIn both ITM groups, the additionally required postoperative systemic morphine dose was significantly reduced compared with the placebo group (P=0.004). One week after operation, patients with ITM reported significantly less pain at rest (P=0.01) compared to the placebo group. At discharge, in comparison with the 0.1 mg ITM and placebo group, the 0.2 mg ITM group showed a higher degree of impairment regarding pain, stiffness, and physical function of the respective joint (P=0.02). Over the further follow-up period of 6 months after surgery, recovery and the quality of life did not differ significantly between the three study groups (P>0.2).ConclusionMorphine (0.1 mg) as adjunct to 0.5% bupivacaine for spinal anesthesia is effective to produce a pronounced postoperative analgesia with a beneficial analgesic effect up to 1 week after surgery. With this study design, the different quality of postoperative analgesia had no effect on quality of life and recovery in patients over the 6-month follow-up period. In the medium term, ITM may induce hyperalgesic effects.

Ultrasound-guided ilioinguinal, iliohypogastric, and genitofemoral nerve block versus spinal subarachnoid blockade for inguinal hernia repair

Introduction All anesthetic methods have been used for inguinal hernia repair surgeries. The use of local anesthesia (LA) techniques such as the ilioinguinal iliohypogastric nerve block (IHNB) may be the most convenient method for patients who are unfit for general anesthesia or spinal anesthesia (SA). The use of ultrasound (US)-guided techniques increases the success rate of the IHNB. The use of intravenous sedation increases the acceptability of LA techniques. Aim The aim of this study was to evaluate the effectiveness, safety, and complications of US-guided IHNB and genital branch of genitofemoral nerve (GF) block in comparison with SA for inguinal hernia repair surgeries. Patients and methods The current study was carried out on 42 patients of American Stroke Association classes I and II. Patients with recurrent, bilateral, irreducible, or large scrotal hernias were excluded. The patients were randomly divided into two equal groups using the closed envelope method, groups 1 and 2. Group 1 included 21 patients who were anesthetized using US-guided IHNB with 25 ml of 0.5% isobaric bupivacaine and genital branch of GF nerve block with 10 ml of 0.5% isobaric bupivacaine. Group 2 included 21 patients who received SA using 3 ml of 0.5% hyperbaric bupivacaine and 25 μg fentanyl. All patients received sedation as continuous propofol infusion. The propofol infusion dose was titrated until the sedation score was 4 using Ramsay Sedation Score. Result Patients receiving IHNB had better hemodynamic stability when compared with the SA group. The total postoperative analgesia was significantly lower and the first dose of postoperative analgesia was significantly delayed in the IHNB group. Postoperative ambulation was significantly early in the IHNB group. Conclusion US-guided IHNB and genital branch of GF nerve block under sedation are good anesthetic techniques for inguinal hernia repair surgeries.

A Prospective Comparative Observational Study of Clinical Efficacy of Isobaric Ropivacaine 0.75% with of Isobaric Bupivacaine 0.5% Intrathecally in Elective Inguinal Hernia Repair Surgeries.

Aims:To evaluate the efficacy of intrathecal isobaric Ropivacaine and its comparison with intrathecal isobaric Bupivacaine in elective inguinal hernia repair surgeries.Settings and Design:A prospective, randomized study was conducted in a tertiary care hospital with 80 patients of ASA grade I-III undergoing elective inguinal hernia repair surgery under spinal anaesthesia. Ethical committee clearance and written consent taken. The patients were randomly divided into two equal groups to the Ropivicaine group (Group R) and to theBupivicaine group (Group B). Parameters observed were onset and duration of sensory and motor block, maximum sensory level achieved degree of motor blockade, two segment regression, and haemodynamic changes.Results:The development of sensory block was faster with Isobaric Ropivicaine (12.1 ± 4.9 minutes) as than isobaric Bupivicaine (13.94 ± 4.52 minutes) but the difference was not statistically significant. Onset of Grade III Motor block was longer with Isobaric Ropivicaine (8.51 ± 3.39 minutes) as compared to isobaric Bupivicaine (8.51 ± 3.39 minutes), but the difference was not statistically significant. Time of Complete Sensory Regression was significantly shorter with Isobaric Ropivicaine (212.69 ± 27.31 minutes) with statistical significance. Time to complete motor recovery was significantly shorter in Ropivacaine group (253.38 ± 27.13 minutes)as compared to Bupivacaine group (258.55 ± 35.81min), with statistical significance. Time to achieve discharge criteria was relatively shorter with Isobaric Ropivicaine. Haemodynamic Parameters did not differ significantly in both the groups during the entire study period.Conclusion:Intrathecal administration of isobaric Ropivacaine (0.75%) 15 mg provides similar quality of spinal anaesthesia but of significantly shorter duration, maintaining similar hemodynamic stability and discharge criteria without significant adverse effects when compared to isobaric Bupivicaine (0.5%) 10 mg.

Epidural analgesia in 20 parturients at the Sylvanus Olympio University Hospital Center in Lomé (Togo)

Etude prospective et descriptive sur la pratique de l’analgésie péridurale (APD) obstétricale au CHU Sylvanus Olympio (CHU SO) de Lomé. Etude menée de février à juin 2014. Après accord des gestantes choisies au hasard et en l’absence de contre-indication à l’issue de la consultation d’anesthésie, faite au 8ème mois de la grossesse, des femmes ont été retenues pour l’étude. Sur 29 gestantes retenues, 20 (69%) ont bénéficiées de l’APD. Age moyen 30,6±6,6 ans, primigestes : 35%, multipares 50%, Obèses (BMI>30): 25%. Nombre moyen de ponctions: 1,2±0,5; reflux de sang dans le cathéter: 5%, brèche dure-mérienne : 0. Délai moyen d’installation: 8,5 ±2,2mn. Quantité moyenne de bupivacaine isobare à 0,125%: 28,8±8ml; Echelle Numérique à T10min < 3 pour toutes les parturientes. Bloc moteur: 0. Hypotension: 1cas (5%). Mode d’accouchement: voie basse: 19 (95%), césarienne: 1 (5%). Détresse respiratoire à la naissance du nouveau né: 0. Note de satisfaction: 9,8±0,5 /10. L’APD obstétricale est possible au CHU Sylvanus Olympio de Lomé. En attendant sa vulgarisation à toutes les parturientes par la disponibilité des moyens humains et matériels, la réaliser pour ses indications médicales serait un premier pas.

Comparison of Efficacy and Safety of Unilateral Spinal Anaesthesia with Sequential Combined Spinal Epidural Anaesthesia for Lower Limb Orthopaedic Surgery.

Orthopaedic anaesthesia plan requires customi-zation as per patient's need for safe outcome. Sequential Combined Spinal Epidural Anaesthesia (Sequential CSEA) and Unilateral Single Shot Spinal anaesthesia (Unilateral SA), both have advantages over conventional spinal anaesthesia that they provide longer lasting block with less hypotension. To compare safety and efficacy of unilateral spinal anaesthesia with sequential combined spinal epidural anaesthesia for lower limb orthopaedic surgery . This prospective randomized study was conducted on sixty ASA I-III patients aged 18- 65 years undergoing lower limb orthopaedic surgeries of approximately two hours duration. Sequential CSE group received spinal with 5 mg of 0.5 hyperbaric bupivacaine followed by incremental epidural top up of 2 cc of 0.5% isobaric bupivacaine to achieve and maintain T10 level. In unilateral SA group, unilateral spinal anaesthesia was given with 10 mg of 0.5% hyperbaric bupivacaine. Haemodynamic parameter, anaesthesia readiness time and block characteristics were recorded and results were analysed using unpaired Student's t-test. There was no failure of block, surgical anaesthesia with T10 sensory level and bromage score three motor block was achieved by all patients in both groups. Anaesthesia readiness time was less in unilateral SA (p<0.001) Incidences of hypotension (p-value 0.0059) and mean ephedrine dose were significantly less in sequential CSEA. Five patients of unilateral SA required supplementation with general anaesthesia. Thus, our study concludes that unilateral SA is a cost-effective and rapidly performed anaesthetic technique. Unilateral SA with 10 mg bupivacaine and sequential CSEA with 5 mg spinal and incremental epidural top up, both provide good quality sensory and motor block for lower limb orthopaedic surgery but sequential CSEA provides significantly more stable haemodynamics with feasibility to prolong block. Thus sequential CSEA should be preferred over unilateral SA in high risk patients especially for major lower limb orthopaedic surgeries.

Epidural Dexmedetomidine and Clonidine as a adjunct with Bupivacaine in patients undergoing lower limb orthopedic Surgeries. A Clinical Study.

Background and Aims: Alpha (α-2) adrenergic agonists have both analgesic and sedative properties when used as an adjuvant in regional anesthesia. A prospective randomized double-blind study was carried out to evaluate the efficacy of epidural route and to compare the efficacy and clinical profile of dexmedetomidine and clonidine as an adjuvant to bupivacaine with special emphasis on their quality of analgesia, sedation and the ability to provide the smooth intra -operative and postoperative course. Material and Methods: The study was conducted in prospective, randomized and double-blind manner. It included 60 American Society of Anesthesiologists Class I and II patients undergoing lower limb surgery under epidural anesthesia. Patients were randomly divided into Group A receiving 0.5% isobaric bupivacaine 15 ml with dexmedetomidine 1 μg/kg and Group B receiving 0.5% isobaric bupivacaine 15 ml with clonidine 2 μg/kg epidurally. Onset and duration of sensory and motor blocks, duration of analgesia, sedation, and adverse effects were assessed . Results: Demographic data, surgical characteristics cardio -respiratory parameters, side-effect profile were comparable and statistically not significant in both the groups. However, sedation scores with dexmedetomidine were better than clonidine and turned out to be statistically significant. The onset times for sensory and motor blocks were significantly shorter in Group A as compared to Group B. The duration of analgesia and motor block was significantly longer in A Group as compared to Group B. Conclusion: Dexmedetomidine is a superior neuraxial adjuvant to bupivacaine when compared to clonidine for early onset of analgesia, superior intra -operative analgesia, stable cardio -respiratory parameters, prolonged postoperative analgesia and providing patient comfort.

Hyperbaric versus isobaric bupivacaine for spinal anaesthesia for caesarean section.

Bupivacaine is an amide local anaesthetic used in hyperbaric and isobaric forms. These are administered intrathecally into the spine to provide regional anaesthesia for caesarean section. Several trials have compared hyperbaric and isobaric bupivacaine but none have conclusively shown the benefit of either. This review was first published in 2013 and updated in 2016. Our objectives were to:1. Determine the effectiveness of hyperbaric bupivacaine compared to isobaric bupivacaine for spinal anaesthesia in women undergoing caesarean section;2. Determine the safety of hyperbaric bupivacaine compared to isobaric bupivacaine for spinal anaesthesia in women undergoing caesarean section. We originally searched the following databases to January 2011: CENTRAL, MEDLINE and Embase.For this update, we reran our search in the above databases from January 2011 to March 2016; two studies are awaiting a response from authors for assessment and will be dealt with when we next update the review.We imposed no language restriction. We included all randomized controlled trials (RCTs) involving parturients undergoing spinal anaesthesia for elective caesarean section that compared the use of hyperbaric with isobaric bupivacaine. Two authors independently extracted the data. The data that were extracted included the number of events and the sample sizes in both the intervention and control groups. For continuous outcomes, we extracted mean and standard deviation.We reported odds ratios (ORs) and risk ratios (RRs) for binary outcomes, and mean differences (MDs) for continuous outcomes. We included three new RCTs in this update, which now comprises 10 studies with a total of 614 participants. We judged most trials as having uncertain risk of bias regarding randomization. Other than this, the overall risk of bias was low. Most included trials had small sample sizes. All of the trials assessed the primary outcome of conversion to general anaesthesia. Ten trials comparing anaesthesia performed with hyperbaric and isobaric bupivacaine failed to show any difference in need for conversion to general anaesthesia (RR 0.33, 95% CI 0.09 to 1.17, 614 participants, very low quality of evidence). Nine trials also failed to show a difference in the need for supplemental analgesics (RR 0.61, 95% CI 0.26 to 1.41, 554 participants, very low quality of evidence). Four trials comparing requirement for ephedrine did not show any difference (RR 0.89, 95% CI 0.57 to 1.38, 256 participants, very low quality of evidence). Seven trials did not provide convincing evidence of difference in nausea and vomiting (RR 0.99, 95% CI 0.57 to 1.72, 433 participants, low quality of evidence). Three trials failed to show a difference in headache (OR 1.82, 95% CI 0.47 to 6.99, 234 participants, low quality of evidence). Two trials showed that the time until sensory block to the thoracic 4th (T4) spinal level was shorter with hyperbaric bupivacaine (MD -1.06 minutes, 95% CI -1.80 to -0.31, 128 participants, moderate quality of evidence). Six trials showed no difference in the amount of ephedrine used (RR 0.23, 95% CI -1.65 to 2.12, 386 participants, moderate quality of evidence). Three trials failed to show any difference in high block (RR 0.88, 95% CI 0.16 to 4.90, 205 participants). Data are limited for some of the outcomes. Reporting of the included trials is less than optimal. For these reasons the overall quality of evidence is low or very low for most of the outcomes, based on the GRADE method of assessment. This review found that intrathecal hyperbaric bupivacaine had a more rapid onset of sensory blockade at the 4th thoracic vertebra (T4) level than isobaric bupivacaine. Hower, despite incorporating more data in the analysis, we found little evidence that the need for conversion to general anaesthesia and supplemental analgesia differed between the hyperbaric or isobaric bupivacaine groups. This is mainly due to the rarity of these outcomes, variability in the dose, use of adjuvant drugs and differences in the technique used for regional anaesthesia. There were no differences in the adverse effects studied. Any possible advantage of hyperbaric bupivacaine needs to be confirmed in larger randomized trials. In future research, criteria for conversion to general anaesthesia need to be defined objectively and applied uniformly.

Prophylactic phenylephrine infusion for the prevention of hypotension after spinal anesthesia in the elderly: a randomized controlled clinical trial

Study objectiveHypotension frequently occurs during spinal anesthesia (SA), especially in the elderly. Phenylephrine is effective to prevent SA-induced hypotension during cesarean delivery. The objective of this study was to evaluate the efficacy and safety of prophylactic infusion of phenylephrine after SA for orthopedic surgery in the elderly. DesignThis prospective, randomized, double-blind, and placebo-controlled study included 54 patients older than 60 years undergoing elective lower limb surgery under SA (injection of 10 mg of isobaric bupivacaine with 5 μg of sufentanyl). InterventionPatients were randomized to group P (100-μg/mL solution of phenylephrine solution at 1 mL/min after placement of SA) or the control group C (0.9% isotonic sodium chloride solution). The flow of the infusion was stopped if the mean arterial blood pressure (MAP) was higher than the baseline MAP and maintained or restarted at 1 mL/min if MAP was equal to or lower than the baseline MAP. Heart rate and MAP were collected throughout the case. MeasurementsHypotension was defined by a 20% decrease and hypertension as a 20% increase from baseline MAP. Bradycardia was defined as a heart rate lower than 50 beats per minute. Main resultsTwenty-eight patients were randomized to group P and 26 patients to group C. MAP was higher in group P than in group C (92 ± 2 vs 82 ± 2 mm Hg, mean ± SD, P< .001). The number of hypotensive episodes per patient was higher in group C compared with group P (9 [0-39] vs 1 [0-10], median [extremes], P< .01), but the number of hypotensive patients was similar between groups (19 [73%] vs 20 [71%], P= 1). The time to onset of the first hypotension was shorter in group C (3 [1-13] vs 15 [1-95] minutes, P= .004). The proportion of patients without hypotension (cumulative survival) was better in group P (P= .04). The number of hypertensive episodes per patient and the number of bradycardic episodes per patient were similar between groups (P= not significant). ConclusionProphylactic phenylephrine infusion is an effective method of reducing SA-induced hypotension in the elderly. Compared with a control group, it delays the time to onset of hypotension and decreases the number of hypotensive episodes per patient. More data are needed to evaluate clinical outcomes of such a strategy.

Intrathecal hyperbaric versus isobaric bupivacaine for adult non-caesarean-section surgery: systematic review protocol

IntroductionBupivacaine is the most commonly used local anaesthetic for spinal anaesthesia (SA). There are two forms of commercially available bupivacaine; isobaric bupivacaine (IB): a formulation with a specific gravity or...

Secondary analysis of outcomes after 11,085 hip fracture operations from the prospective UK Anaesthesia Sprint Audit of Practice (ASAP-2).

We re-analysed prospective data collected by anaesthetists in the Anaesthesia Sprint Audit of Practice (ASAP-1) to describe associations with linked outcome data. Mortality was 165/11,085 (1.5%) 5 days and 563/11,085 (5.1%) 30 days after surgery and was not associated with anaesthetic technique (general vs. spinal, with or without peripheral nerve blockade). The risk of death increased as blood pressure fell: the odds ratio (95% CI) for mortality within five days after surgery was 0.983 (0.973-0.994) for each 5 mmHg intra-operative increment in systolic blood pressure, p = 0.0016, and 0.980 (0.967-0.993) for each mmHg increment in mean pressure, p = 0.0039. The equivalent odds ratios (95% CI) for 30-day mortality were 0.968 (0.951-0.985), p = 0.0003 and 0.976 (0.964-0.988), p = 0.0001, respectively. The lowest systolic blood pressure after intrathecal local anaesthetic relative to before induction was weakly correlated with a higher volume of subarachnoid bupivacaine: r(2) -0.10 and -0.16 for hyperbaric and isobaric bupivacaine, respectively. A mean 20% relative fall in systolic blood pressure correlated with an administered volume of 1.44 ml hyperbaric bupivacaine. Future research should focus on refining standardised anaesthesia towards administering lower doses of spinal (and general) anaesthesia and maintaining normotension.

SPINAL ANESTHESIA

Objective: The purpose of the study is to compare and assess the sensoryand motor block along with the associated hemodynamic changes that occur in the patientpopulation operated for a lower segment cesarean section (LSCS), when they are given 0.5%hyperbaric bupivacaine versus 0.5% isobaric bupivacaine as used for spinal anesthesia.Study Design: Prospective double blind randomized trial. Period: 6 months duration fromApril 2014 to September 2014. Setting: A tertiary care hospital in the city of Karachi, Pakistan.Method: The study population consisted of 60 patients belonging to the ASA 1 and ASA 2category, who underwent a lower segment cesarean section, and comparative analysis ofthe efficacy and associated hemodynamic changes of hyperbaric with isobaric bupivacaine.The patient population was segmented into two groups both groups containing 30 patients,group A receiving hyperbaric bupivacaine 0.5% as 2.5ml ( 12.5mg dose ) and the secondgroup designated as, group B receiving isobaric bupivacaine 0.5% as 2.5ml ( 12.5mg dose)intrathecally. The resultant sensory and motor blockade was determined using pin prick andbromage scale respectively. Results: There was a significant difference found among the twogroups under study, when compared at 3min interval regarding the sensory blockade. The levelof T6 block was reached in 33.33% (n=10) patients belonging to group A and 56.66% (n= 17)patients in group B. It was observed that there was no significant change among the two groupsat 5min interval regarding sensory and motor blockade respectively. The immediate sensoryblockade with isobaric bupivacaine in group B produced greater decrease in the systolic andmean arterial blood pressure when contrasted with hyperbaric bupivacaine in group A at 5mininterval, but after time interval of 45min there was no statistically significant change observed.Conclusions: According to our study the effects of isobaric bupivacaine were more significantlypredictable; hence have a higher efficacy, when contrasted against hyperbaric bupivacainein lower section cesarean section spinal anesthesia. Quick sensory blockade with isobaricbupivacaine was associated with more decrease in blood pressures when contrasted with thehyperbaric bupivacaine, but this result is not statistically significant.

English

Objective: The purpose of the study is to compare and assess the sensory and motor block along with the associated hemodynamic changes that occur in the patient population operated for a lower segment cesarean section (LSCS), when they are given 0.5% hyperbaric bupivacaine versus 0.5% isobaric bupivacaine as used for spinal anesthesia. Study Design: Prospective double blind randomized trial. Period: 6 months duration from April 2014 to September 2014. Setting: A tertiary care hospital in the city of Karachi, Pakistan. Method: The study population consisted of 60 patients belonging to the ASA 1 and ASA 2 category, who underwent a lower segment cesarean section, and comparative analysis of the efficacy and associated hemodynamic changes of hyperbaric with isobaric bupivacaine. The patient population was segmented into two groups both groups containing 30 patients, group A receiving hyperbaric bupivacaine 0.5% as 2.5ml ( 12.5mg dose ) and the second group designated as, group B receiving isobaric bupivacaine 0.5% as 2.5ml ( 12.5mg dose) intrathecally. The resultant sensory and motor blockade was determined using pin prick and bromage scale respectively. Results: There was a significant difference found among the two groups under study, when compared at 3min interval regarding the sensory blockade. The level of T6 block was reached in 33.33% (n=10) patients belonging to group A and 56.66% (n= 17) patients in group B. It was observed that there was no significant change among the two groups at 5min interval regarding sensory and motor blockade respectively. The immediate sensory blockade with isobaric bupivacaine in group B produced greater decrease in the systolic and mean arterial blood pressure when contrasted with hyperbaric bupivacaine in group A at 5min interval, but after time interval of 45min there was no statistically significant change observed. Conclusions: According to our study the effects of isobaric bupivacaine were more significantly predictable; hence have a higher efficacy, when contrasted against hyperbaric bupivacaine in lower section cesarean section spinal anesthesia. Quick sensory blockade with isobaric bupivacaine was associated with more decrease in blood pressures when contrasted with the hyperbaric bupivacaine, but this result is not statistically significant.

A randomized controlled study comparing intrathecal hyperbaric bupivacaine-fentanyl mixture and isobaric bupivacaine-fentanyl mixture in common urological procedures.

Background and Aims:Bupivacaine is available in isobaric and hyperbaric forms for intrathecal use and opioids are used as additives to modify their effects. The aim of this study was to compare the efficacy and haemodynamic effect of intrathecal isobaric bupivacaine-fentanyl mixture and hyperbaric bupivacaine-fentanyl mixture in common urological procedures.Methods:One hundred American Society of Anesthesiologists physical status 1 and 2 patients undergoing urological procedures were randomized into two groups. Group 1 received 3 ml of 0.5% isobaric bupivacaine with 25 μg fentanyl while Group 2 received 3 ml of 0.5% hyperbaric bupivacaine with 25 μg fentanyl. The parameters measured include heart rate, blood pressure, respiratory rate, onset and duration of motor and sensory blockade. Student's unpaired t-test and the χ2 test were used to analyse the results, using the SPSS version 11.5 software.Results:The haemodynamic stability was better with isobaric bupivacaine fentanyl mixture (Group 1) than with hyperbaric bupivacaine fentanyl mixture (Group 2). The mean onset time in Group 1 for both sensory block (4 min) and motor block (5 min) was longer compared with Group 2. The duration of sensory block (127.8 ± 38.64 min) and motor block (170.4 ± 27.8 min) was less with isobaric bupivacaine group compared with hyperbaric bupivacaine group (sensory blockade 185.4 ± 16.08 min and motor blockade 201.6 ± 14.28 min). Seventy percent of patients in Group 2 had maximum sensory block level of T6 whereas it was 53% in Group 1. More patients in Group 1 required sedation compared to Group 2.Conclusion:Isobaric bupivacaine fentanyl mixture was found to provide adequate anaesthesia with minimal incidence of haemodynamic instability.

Stress-related biomarkers in dogs administered regional anaesthesia or fentanyl for analgesia during stifle surgery

ObjectivesTo compare the effects of regional anaesthesia and opioid administration on adrenocortical and glycaemic responses, postoperative pain and recovery quality in dogs undergoing stifle surgery. Study designProspective, blinded clinical study. AnimalsForty-five dogs anaesthetized for tibial tuberosity advancement or tibial plateau levelling osteotomy, and 15 healthy dogs undergoing non-invasive orthopaedic diagnostic procedures. MethodsThe baseline behaviour of each dog was classified on a descriptive scale before anaesthesia. Dogs were anaesthetized using a standard protocol. Those undergoing surgery were randomly assigned to one of three intraoperative analgesia protocols: 1) peripheral (femoral and sciatic) nerve block (bupivacaine 0.5%; 0.15 mL kg−1 in each nerve; group PNB); 2) spinal anaesthesia (isobaric bupivacaine 0.5%; 0.05 mL kg−1; group SPI); and 3) intravenous fentanyl variable rate infusion and postoperative methadone (0.2 mg kg−1; group FEN). Blood samples were collected for measurement of cortisol and glucose concentrations on arrival (TAR), at induction (TIND), at tracheal extubation (TEXT), and 1 hour post-extubation (TPEX). After extubation, a researcher unaware of the dog’s group assignment evaluated pain and recovery quality using the Glasgow Composite Measure Pain Scale (Short-Form) and a descriptive scale, respectively. ResultsMedian recovery quality was significantly worse in group FEN (p < 0.0001) compared with all other groups. Postoperative pain scores were lower in group PNB compared with groups SPI and FEN. Cortisol and glucose concentrations increased significantly from TAR at TEXT and TPEX (p < 0.0001) in group FEN, and were unchanged from TAR in the other groups. Conclusions and clinical relevanceAnalgesia with a peripheral nerve block or spinal anaesthesia prevented the glycaemic and cortisol responses to surgery, promoted better recovery quality, and decreased postoperative pain scores compared with FEN. In the present study, the regional anaesthesia techniques used were found to be excellent alternatives to fentanyl administration.

Transient loss of voice during labour analgesia.

Sir, A 30-year-old full term American Society of Anesthesiologists 1 primigravida patient was administered labour analgesia (LA) on demand at 4-5 cm cervical dilation employing combined spinal epidural (CSE) technique. In sitting position, assuring asepsis, 18 g epidural catheter was sited in L2-3 space threaded up to 10 cm, checked and fixed. After that, 1cc of 0.125% preservative free isobaric bupivacaine (1cc of 0.25% preservative free bupivacaine double diluted with sterile normal saline) and 10 μg fentanyl was injected intrathecally via 26 g Quincke needle at L3-4 space. Maternal and foetal vital parameters remained stable. She had satisfactory pain relief in 10 min and was chatting comfortably when suddenly after 12 min, we noticed loss of voice (she was unable to talk). Other than that there was no neurodeficit or dyspnoea. Spinal level was limited to T6. She was fully awake, oriented and continued communication with us by writing. All maternal and foetal vital parameters remained normal. She was pain free and her labour progressed normally. She was worried but not hysterical. No further abnormality was revealed in neurology consultation. As no further deterioration was noted, we counselled the patient and relatives regarding this event being a rare but reversible drug side effect and reassured them about both maternal and foetal well-being. Epidural bolus was held off, which otherwise would be given at 30 min after spinal injection. By 45 min of the event the phonation started returning and by 1 h she was able to speak normally. Simultaneously cervix was found to be fully dilated and she went on to have a normal vaginal delivery. Ten millilitre 0.25% bupivacaine was given epidurally for episiotomy suturing. The epidural catheter was removed after suturing. The post-operative recovery, hospital stay and follow up for 3 months was uneventful. Cerebral complications of preeclampsia, thrombo-embolic phenomena, absence seizure or high spinal can mimic symptoms of transient ischaemic attack in a parturient. However, our patient did not fit into any of these categories. Kuczkowski and Goldsworthy[1] reported a case of a previously healthy parturient who received 10 μg of fentanyl combined with 2.5 mg of bupivacaine intrathecally as a part of CSE technique for LA and At 4 min after intrathecal injection she suddenly developed transient aphonia and aphagia. The pinprick sensory level of analgesia was found to be at T3 and her symptoms resolved in 20 min. Gupta et al.[2] reported aphonia and aphagia in a male patient posted for lower limb debridement at 3 min after receiving 12.5 mg heavy bupivacaine with 25 μg fentanyl intrathecally which recovered spontaneously in 10-15 min. In both cases the authors believe extensive cephalad spread of fentanyl through the Cerebrospinal fluid (CSF) as the cause for neurological symptoms. There has been a study which noted rapid cephalad spread of fentanyl in the cervical CSF after lumbar administration.[3] Sudden onset, life-threatening respiratory depression have been reported following administration of intrathecal fentanyl for labour analgesia which suggest that lipophilic opioids may move rapidly from lumbar cistern to brainstem level via CSF.[4] There may be more rapid rise in CSF concentrations of drug due to pregnancy related changes. Rapid clearance of fentanyl from the CSF might explain the transient nature of symptoms. Some cases have been reported where similar side effects were noted to be reversed using opioid antagonists naloxone and nalbuphine[5] supporting the cause to be the opioid. Many similar unreported incidences may have been attributed to over anxious and hysterical nature of patients. CSE using fentanyl is one of the established techniques for labour analgesia with minimal side effects. It is necessary to be aware of this rare side effect and maintain composure, provide reassurance to patient and reverse drug effect if needed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Comparison of spinal anesthesia dosage based on height and weight versus height alone in patients undergoing elective cesarean section.

BackgroundSpinal anesthesia with bupivacaine, typically used for elective and emergency cesarean section, is associated with a significant incidence of hypotension resulting from sympathetic blockade. A variety of dosing regimens have been used to administer spinal anesthesia for cesarean section. The objective of this study was to compare the incidence of hypotension following two different fixed dosing regimens.MethodsThis was a randomized double-blind clinical trial with a two-sided design, 5% significance level and 80% power. After approval of the hospital ethics review committee, 60 patients were divided randomly into two groups. In one group, the local anesthetic dose was adjusted according to height and weight, and in the other, the dose was adjusted according to height only.ResultsSixty women with a singleton pregnancy were included. Of the factors that could affect dose and blood pressure, including age, weight, height, and dose, only height differed between the groups. Mean heart rate was similar between the groups. Hypotension was significantly more frequent with dosage based on height alone than with two-factor dose calculation (56.7% vs. 26.7%; P = 0.018).ConclusionsAdjusting the dose of isobaric bupivacaine to a patient's height and weight provides adequate anesthesia for elective cesarean section and is associated with a decreased incidence and severity of maternal hypotension and less use of ephedrine.