Dose Of Intrathecal Bupivacaine Research Articles

Height Adjusted Dose versus Height-Weight Adjusted Dose of Intrathecal Hyperbaric Bupivacaine for Caesarean Delivery for Preventing Maternal Hypotension: A Prospective, Double-Blinded, Randomized Controlled Study

Background: Spinal anesthesia for cesarean section is associated with significant hypotension due to sympathetic blockade and can cause adverse maternal and fetal outcomes. Although hypotension is considered to be dose-dependent, choosing a dose of bupivacaine to achieve an adequate level of blockade without causing hypotension is a challenge. Methods: Ninety-six eligible parturients posted for elective cesarean section under spinal anesthesia were divided into two groups. Group H received intrathecal bupivacaine dose calculated as per patients’ height and Group HW received intrathecal bupivacaine dose calculated as per patients’ height and weight chart. Heart rate and mean blood pressure were monitored in both groups. Time required to achieve sensory block up to T6, complete motor block, the dose of ephedrine required to treat hypotension, the incidence of complications, and neonatal appearance, pulse, grimace, activity, respiration (APGAR) scores were noted. Results: Hypotension occurred in 35.56% of parturients in Group H and 16.28% of parturients in Group HW, which was statistically significant. The mean dose of 0.5% bupivacaine was 9.12 mg in Group HW and 9.4 mg in Group H (P value = 0.02). The mean dose of Ephedrine was 12 ± 5.8 mg in Group H compared to 6.0 mg in Group HW, which was statistically significant. The time needed to achieve sensory and complete motor block were comparable in both groups. Conclusion: Height-weight-adjusted intrathecal hyperbaric bupivacaine achieved comparable sensory and motor block with lesser incidence and severity of hypotension compared to height-adjusted dose.

Randomized Double-Blind Study of the Effect of Injectate Temperature on Intrathecal Bupivacaine Dose Requirement in Spinal Anesthesia for Cesarean Delivery.

Increasing the temperature of intrathecal local anesthetics has been shown to increase the speed of onset and block height of spinal anesthesia. However, how this influences dose requirement has not been fully quantified. The aim of this study was to determine and compare the effective dose for anesthesia for cesarean delivery in 50% of patients (ED50) of intrathecal bupivacaine given at temperatures of 37 °C (body temperature) or 24 °C (room temperature). Eighty healthy parturients having elective cesarean delivery under combined spinal-epidural anesthesia were randomly assigned to receive intrathecal hyperbaric bupivacaine stored at 37 °C (body temperature group) or 24 °C (room temperature group). The first subject in each group received a bupivacaine dose of 10 mg. The dose for each subsequent subject in each group was varied with an increment or decrement of 1 mg based on the response (effective or noneffective) of the previous subject. Patients for whom the dose was noneffective received epidural supplementation after data collection with lidocaine 2% as required until anesthesia was sufficient for surgery. Values for ED50 were calculated using modified up-down sequential analysis with probit analysis applied as a backup sensitivity analysis. These values were compared and the relative mean potency was calculated. The ED50 (mean [95% confidence interval, CI]) of intrathecal hyperbaric bupivacaine was lower in the body temperature group (6.7 [5.7-7.6] mg) compared with the room temperature group (8.1 [7.7-8.6] mg) (P < .05). The relative potency ratio for intrathecal bupivacaine for the room temperature group versus the body temperature group was 0.84 (95% CI, 0.77-0.93). Warming hyperbaric bupivacaine to body temperature reduced the dose requirement for spinal anesthesia for cesarean delivery by approximately 16% (95% CI, 7%-23%).

Height-adjusted dose of intrathecal bupivacaine on surgical anesthesia for the cesarean section

Background: In the spinal anesthetic technique, local anesthetic dose (concentration and volume) is the main determinant of its adequacy and success of block to be achieved. The lack of pain during surgical intervention rather than on dermatome sensory block level is considered to be an appropriate indicator of surgical anesthesia. Spinal anesthesia is the most common anesthetic technique to provide anesthesia for the elective or emergent cesarean section (CS). However, spinal block-induced maternal hypotension is the most common adverse effect during single-shot spinal anesthesia. In our study, we aim to study the height-adjusted dose of 0.5% Bupivacaine Heavy (BH) in achieving surgical anesthesia and its effect on maternal hypotension. Participants and Method: One hundred parturients scheduled for elective CS were enrolled and were compared to the parallel arms of parturients receiving conventional BH. Fifty parturients in each group were included. In the conventional group (B), participants received spinal block with 12 mg of 0.5% BH, and in the height adjusted-dose group (H), participants received a dose of 0.5% BH in 0.06 mg per centimetre height. A sensory block level of T6 dermatome or higher was consider adequate to start surgery. The adequate surgical anesthesia is considered to be achieved if cesarean delivery can be performed without supplementary analgesia. The need of supplementary analgesia, conversion to general anesthesia, or no block till 15 min of intrathecal BH is considered spinal failure. Results: 4% of the height-adjusted dose group have a low block level. Two cases complained of pain, and of them, one received supplementary analgesia and one was converted to general anesthesia. Systolic hypotension of a maternal blood pressure of less than 90 mm Hg was found in 19 (38%) and 10 (20%) in the conventional group and HAD group, respectively, which was highly significant statistically (p value 0.001%). Conclusion: Intrathecal hyperbaric bupivacaine in height adjusted 0.06 mg per cm height of patient can achieve surgical anesthesia with maintainance of systolic blood pressure. However, low dosing of intrathecal BH has higher cases of block failure in comparison to the conventional fixed dose regime of spinal anesthesia.

Synergistic effect of inthrathecal fentanyl and bupivacaine in spinal anesthesia for cesarean section in Baghdad city

Background: Potentiating the effect of intrathecal local anesthetics drugs by addition of intrathecal opiods for intra-abdominal surgeries had been used lately. In this study by addition of fentanyl, we tried to minimize the dose of bupivacaine thereby reducing the side effect caused by higher doses of intrathecal bupivacaine in cesarean section, and to improve the quality of block.Methods: Study was performed on sixty patients underwent cesarean section they were divided into 6 groups as B10, B 12.5, B15 mg of bupivacaine and FB10, FB12.5, FB15 received a combination of 25 µg intrathecal fentanyl respectively, the parameter taken into consideration were visceral pain, hemodynamic stability (hypotension and bradycardia) intra operative sedation, nausea, vomiting and post-operative pain. Results: Onset of sensory block to T6 occurred faster with increasing bupivacaine doses in bupivacaine only groups and bupivacaine fentanyl combination groups. Alone lower concentration of bupivacaine could not completely remove the visceral pain. Blood pressure declined with increasing the concentration of bupivacaine and fentanyl. The incidence of nausea and vomiting was reduced significantly while post-operative pain relief and hemodynamics stability increased by adding fentanyl. Pruritis, maternal respiratory depression and changes in APGAR score of babies did not occur with fentanyl. Conclusions: Spinal anesthesia among the neuro axial blocks in obstetric patients’ needs strict dose calculation because minimal dose changes results in more complications and side effects Here the synergistics potentiating effects of fentanyl (an opiod) on bupivicaine (local anesthetic) in spinal anesthesia for cesarean section is presented. Fentanyl is able to reduce a dose of bupivicaine and therefore its harmful effect.

Analgesic Outcomes in Opioid Use Disorder Patients Receiving Spinal Anesthesia with or without Intrathecal Clonidine for Cesarean Delivery: A Retrospective Investigation.

BackgroundIntrathecal (IT) clonidine has been observed to reduce 24-hour opioid requirements and time to first analgesic request after cesarean delivery, but has not been specifically studied in patients with opioid use disorder (OUD).MethodsPatients with OUD undergoing cesarean delivery under spinal or combined spinal-epidural (CSE) anesthesia at our institution from 2011 to 2020 were identified, and only patients with OUD were included in this study. Subjects that received IT clonidine were compared to a control group that did not receive IT clonidine to observe potential differences in analgesic outcomes (24-hour opioid requirements, pain scores and time to first post-operative pain medication) or side-effects (hypotension, vasopressor dosing and bradycardia).ResultsA total of 160 patients were included (clonidine n = 22, controls n = 138). For the clonidine group, the median IT clonidine dose was 30µg. Clonidine group patients were observed to have greater dose of IT bupivacaine (12 vs 12.75mg; p = 0.01) and IT morphine (100 vs 200µg; p < 0.001). The clonidine group was also observed to have greater incidence of intraoperative hypotension (20% vs 45%; p = 0.01) and maximum phenylephrine dose (50 vs 57.5 µg/min; p < 0.001). The time to first analgesic request (minutes) after surgery was significantly longer for the clonidine group (153.5 vs 207 min; p < 0.001). The average oral oxycodone equivalents taken per 24 hours of hospital admission were significantly less in the clonidine group (82.36 vs 41.67mg; p < 0.001), and the clonidine group also had significantly less oxycodone equivalents taken for each post-operative day.ConclusionIT clonidine was observed to result in reduced 24-hour opioid consumption in patients with OUD and may be useful as part of a multimodal analgesic regimen. The incidence of hypotension and vasopressor doses were greater in patients receiving IT clonidine, and this should be anticipated if IT clonidine is being administered.

A prediction model using machine-learning algorithm for assessing intrathecal hyperbaric bupivacaine dose during cesarean section

BackgroundThe intrathecal hyperbaric bupivacaine dosage for cesarean section is difficult to predetermine. This study aimed to develop a decision-support model using a machine-learning algorithm for assessing intrathecal hyperbaric bupivacaine dose based on physical variables during cesarean section.MethodsTerm parturients presenting for elective cesarean section under spinal anaesthesia were enrolled. Spinal anesthesia was performed at the L3/4 interspace with 0.5% hyperbaric bupivacaine at dosages determined by the anesthesiologist. A spinal spread level between T4-T6 was considered the appropriate block level. We used a machine-learning algorithm to identify relevant parameters. The dataset was split into derivation (80%) and validation (20%) cohorts. A decision-support model was developed for obtaining the regression equation between optimized intrathecal 0.5% hyperbaric bupivacaine volume and physical variables.ResultsA total of 684 parturients were included, of whom 516 (75.44%) and 168 (24.56%) had block levels between T4 and T6, and less than T6 or higher than T4, respectively. The appropriate block level rate was 75.44%, with the mean bupivacaine volume [1.965, 95%CI (1.945,1.984)]ml. In lasso regression, based on the principle of predicting a reasonable dose of intrathecal bupivacaine with fewer physical variables, the model is “Y=0.5922+ 0.055117* X1-0.017599*X2” (Y: bupivacaine volume; X1: vertebral column length; X2: abdominal girth), with λ 0.055, MSE 0.0087, and R2 0.807.ConclusionsAfter applying a machine-learning algorithm, we developed a decision model with R2 0.8070 and MSE due to error 0.0087 using abdominal girth and vertebral column length for predicting the optimized intrathecal 0.5% hyperbaric bupivacaine dosage during term cesarean sections.

Comparison of two low dose local anesthetics in combination with morphine for spinal anesthesia for total knee arthroplasty

There is a lack of consensus on the combination doses of local anesthetics and opioids for spinal anesthesia in patients undergoing total knee arthroplasty (TKA) surgery. Opioids and local anesthetic combinations are associated with many postoperative side effects at high doses. We aimed to assess the use of the lowest possible doses of intrathecal bupivacaine and morphine for TKA.

Minimal Local Analgesic Dose of Intrathecal Bupivacaine and Ropivacaine in Patients Undergoing Cesarean Section: A Comparative Study

Introduction: Spinal anesthesia is a reasonable option for cesarean section. Bupivacaine and ropivacaine have been used as intrathecal drugs alone or in combination with various opiods. Ropivacaine is considered a valid and safe alternative to bupivacaine for intrathecal anesthesia. This study aims to determine the median effective dose (ED50) of intrathecal bupivacaine and ropivacaine for cesarean section and defines this as the minimum local anesthetic dose (MLAD). Methods: Forty pregnant women undergoing elective cesarean section were allocated and randomized into two groups. The initial dose was 13mg for both ropivacaine and bupivacaine groups and was increased or decreased of 0.3mg, using the up-down sequential allocation technique. Efficacy was accepted if adequate sensory dermatomal anesthesia to pinprick to T6 was attained within 20 minutes after intrathecal injection and required no supplemental epidural injection for procedure until at least 50 minutes after the intrathecal injection of test drugs. The MLAD for both bupivacaine and ropivacaine was calculated with 95% confidence interval using the formula of Dixon and Massey. Comparison of different variables between the groups was done using t-test with significant p value at &lt; 0.05. Results: The two groups were comparable in terms of demographic profile and clinical characteristics. The MLAD of ropivacaine and bupivacaine were 11.63 mg (95% CI, 11.5-12.92) and 10.459 mg (95% CI, 10.12-10.87) respectively. The potency ratio between spinal ropivacaine and bupivacaine was 0.89. Conclusion: Ropivacaine provided clinically surgical anaesthesia of shorter duration without compromising neonatal outcome and can be used as a safe alternative to bupivacaine.

Combined spinal and general anaesthesia in 58 cats undergoing various surgical procedures: description of technique and retrospective perioperative evaluation.

The aim of this retrospective study was to describe the spinal anaesthesia (SA) technique and evaluate the incidence of perioperative complications in cats. The anaesthetic records of cats of American Society of Anaesthesiologists physical status I, II and III, which received general and SA for different surgeries between 2012 and 2016, were examined. SA was administered through a 25 G Quincke needle, using an isobaric solution of bupivacaine and morphine at the level of either the L7-S1 interspaces (sternal recumbency) or the L5-6/L6-7 interspaces (lateral recumbency). Procedural failure rate (PFR), drugs and dose used, heart rate (HR), arterial blood pressure, incidence of bradycardia (HR <100 bpm) and hypotension (mean arterial pressure [MAP] <60 mmHg for at least 5 mins), intraoperative rescue analgesia (iRA) and any other detrimental events and their treatment until discharge were recorded. Abdominal surgery cases were excluded from the intraoperative evaluation. A total of 58 anaesthetic records met the inclusion criteria and were analysed. PFR related to the space of injection (L7-S1 vs L5-6/L6-7) was 3/11 (27%) and 1/47 (2%), respectively (P = 0.017). The total median dose of intrathecal bupivacaine and morphine was 0.8 (range 0.5-1.6 mg/kg) and 0.10 (0.05-0.18 mg/kg), respectively. Nine of 46 (20%) cats received iRA, and no iRA cases were reported with a dose of bupivacaine higher than 0.8 mg/kg. Median HR and MAP before intrathecal injection (T0) and 10 mins after (T1) were, respectively, 118 bpm (range 74-190 bpm) and 106 bpm (67-160 bpm) (P = 0.005), and 65 mmHg (range 50-94 mmHg) and 52 mmHg (range 35-85 mmHg) (P = 0.003). Bradycardia was reported in 18/46 (39%) cats and hypotension in 23/46 (50%) cats. No complications were recorded during the observation period. SA was characterised by a low PFR when performed at the L5-6/L6-7 interspaces and low postoperative complications. Hypotension and bradycardia were the most common side effects.

Effect of Intrathecal Bupivacaine Dose on the Success of External Cephalic Version for Breech Presentation: A Prospective, Randomized, Blinded Clinical Trial

(Anesthesiology 2017;127:625–632) Increased rate of cesarean delivery without measurable improvements in maternal or neonatal outcomes is a major public health problem. Breech presentation is a major contributor to the incidence of cesarean delivery and can be prevented by external cephalic version (ECV). Neuraxial blockade for ECV improves maternal satisfaction and procedural success and decreases maternal pain. Meta-analysis of randomized controlled trials suggests that administering higher doses of local anesthetic (LA) for neuraxial block leads to increased ECV success, although the protocol for providing neuraxial blockade for this procedure has not yet been standardized.

Prophylactic infusion of phenylephrine increases the median effective dose of intrathecal hyperbaric bupivacaine in cesarean section: A prospective randomized study.

Background:Phenylephrine infusion to prevent spinal-induced hypotension can attenuate cephalic spread of intrathecal bupivacaine. Therefore, we suspected the intrathecal dose requirement for bupivacaine may differ when using phenylephrine infusion to prevent spinal-induced hypotension in cesarean section. We designed a prospective, randomized study to determine the ED50 of hyperbaric bupivacaine for cesarean section under combined spinal-epidural anesthesia in healthy parturients with and without prophylactic phenylephrine infusion to prevent spinal-induced hypotension.Methods:Sixty healthy parturients rated American Society for Anesthesiology status I/II undergoing elective cesarean section were enrolled in this study, which was conducted July 2016 to February 2017 in the labor and delivery department of Jiaxing University Affiliated Women and Children Hospital. After enrollment, patients were randomized into 2 groups of 30 by blinded opaque envelopes sorted by computer-generated random allocation. Solutions were prepared by an anesthesiologist not involved in outcome measurement. Patients and anesthesiologists collecting data were blinded to group allocation. Group P (phenylephrine group) parturients received prophylactic infusion of phenylephrine at the time of intrathecal injection. Group S (saline group) parturients receive the same volume of saline. Doses of intrathecal bupivacaine for each patient were determined using an up-down allocation method; initial dose was 7 mg. Effective dose was defined as bilateral T6 or above sensory block level achieved within 10 minutes of intrathecal drug administration and no additional epidural lidocaine required for intraoperative pain. The Dixon and Massey formula was used to calculate ED50 values.Results:The ED50 values for hyperbaric bupivacaine were 7.0 mg (95% confidence interval [CI]: 6.6–7.4 mg) and 4.9 mg (95% CI: 4.4–5.4 mg) for groups P and S, respectively (P < .001). There were significant differences in incidence of hypotension and pH of umbilical arterial blood between groups S and P (60% vs 10%, P = .04 and 7.31 ± 0.04 vs 7.28 ± 0.06, P = .003, respectively).Conclusion:The ED50 of intrathecal hyperbaric bupivacaine is higher when phenylephrine infusion is used to prevent spinal-induced hypotension than when it is not used.

Combined spinal epidural for labor analgesia comparison of two different doses of intrathecal bupivacaine 1.25 mg and fentanyl 25 µg with bupivacaine 2.5 mg and fentanyl 25 µg

Combined spinal epidural for labor analgesia comparison of two different doses of intrathecal bupivacaine 1.25 mg and fentanyl 25 µg with bupivacaine 2.5 mg and fentanyl 25 µg

Comparison of two Different Low Doses of Intrathecal Bupivacaine &amp; Fentanyl Mixture in Caesarean Section &amp; to see the Relevance of Preloading in Them

Comparison of two Different Low Doses of Intrathecal Bupivacaine &amp; Fentanyl Mixture in Caesarean Section &amp; to see the Relevance of Preloading in Them

Effect of Intrathecal Bupivacaine Dose on the Success of External Cephalic Version for Breech Presentation: A Prospective, Randomized, Blinded Clinical Trial.

Breech presentation is a leading cause of cesarean delivery. The use of neuraxial anesthesia increases the success rate of external cephalic version procedures for breech presentation and reduces cesarean delivery rates for fetal malpresentation. Meta-analysis suggests that higher-dose neuraxial techniques increase external cephalic version success to a greater extent than lower-dose techniques, but no randomized study has evaluated the dose-response effect. We hypothesized that increasing the intrathecal bupivacaine dose would be associated with increased external cephalic version success. We conducted a randomized, double-blind trial to assess the effect of four intrathecal bupivacaine doses (2.5, 5.0, 7.5, 10.0 mg) combined with fentanyl 15 μg on the success rate of external cephalic version for breech presentation. Secondary outcomes included mode of delivery, indication for cesarean delivery, and length of stay. A total of 240 subjects were enrolled, and 239 received the intervention. External cephalic version was successful in 123 (51.5%) of 239 patients. Compared with bupivacaine 2.5 mg, the odds (99% CI) for a successful version were 1.0 (0.4 to 2.6), 1.0 (0.4 to 2.7), and 0.9 (0.4 to 2.4) for bupivacaine 5.0, 7.5, and 10.0 mg, respectively (P = 0.99). There were no differences in the cesarean delivery rate (P = 0.76) or indication for cesarean delivery (P = 0.82). Time to discharge was increased 60 min (16 to 116 min) with bupivacaine 7.5 mg or higher as compared with 2.5 mg (P = 0.004). A dose of intrathecal bupivacaine greater than 2.5 mg does not lead to an additional increase in external cephalic procedural success or a reduction in cesarean delivery.

Abdominal girth and vertebral column length aid in predicting intrathecal hyperbaric bupivacaine dose for elective cesarean section.

Currently, there is no consensus on how to determine the optimal dose of intrathecal bupivacaine for an individual undergoing an elective cesarean section. In this study, we developed a regression equation between intrathecal 0.5% hyperbaric bupivacaine volume and abdominal girth and vertebral column length, to determine a suitable block level (T5) for elective cesarean section patients.In phase I, we analyzed 374 parturients undergoing an elective cesarean section that received a suitable dose of intrathecal 0.5% hyperbaric bupivacaine after a combined spinal-epidural (CSE) was performed at the L3/4 interspace. Parturients with T5 blockade to pinprick were selected for establishing the regression equation between 0.5% hyperbaric bupivacaine volume and vertebral column length and abdominal girth. Six parturient and neonatal variables, intrathecal 0.5% hyperbaric bupivacaine volume, and spinal anesthesia spread were recorded. Bivariate line correlation analyses, multiple line regression analyses, and 2-tailed t tests or chi-square test were performed, as appropriate. In phase II, another 200 parturients with CSE for elective cesarean section were enrolled to verify the accuracy of the regression equation.In phase I, a total of 143 parturients were selected to establish the following regression equation: YT5 = 0.074X1 − 0.022X2 − 0.017 (YT5 = 0.5% hyperbaric bupivacaine volume for T5 block level; X1 = vertebral column length; and X2 = abdominal girth). In phase II, a total of 189 participants were enrolled in the study to verify the accuracy of the regression equation, and 155 parturients with T5 blockade were deemed eligible, which accounted for 82.01% of all participants.This study evaluated parturients with T5 blockade to pinprick after a CSE for elective cesarean section to establish a regression equation between parturient vertebral column length and abdominal girth and 0.5% hyperbaric intrathecal bupivacaine volume. This equation can accurately predict the suitable intrathecal hyperbaric bupivacaine dose for elective cesarean section.

Intrathecal analgesia by bupivacaine is not enhanced by coadministration of morphine in patients with severe cancer-related pain: a randomized double-blind cross-over study.

These results suggest that patients with cancer-related pain treated with high doses of systemic opioids, may start IT treatment with an optimal dose of IT bupivacaine without morphine. .

Comparative Study of Low Doses of Intrathecal Bupivacaine Admixed With Fentanyl Citrate in Caesarean Section Deliveries

Comparative Study of Low Doses of Intrathecal Bupivacaine Admixed With Fentanyl Citrate in Caesarean Section Deliveries

Clinical Study to Determine the Efficacy of Clonidine as an Adjuvant to Intrathecal Bupivacaine in Patients Undergoing Cesarean Section.

Introduction:Spinal anesthesia with bupivacaine is associated with hypotension and inadequate postoperative analgesia. The addition of clonidine as an adjuvant to intrathecal bupivacaine is beneficial in reducing the dose of the local anesthetic and also provides prolonged postoperative analgesia.Methodology:One hundred and five American Society of Anesthesiologists physical status Classes 1 and 2 parturient women undergoing elective cesarean section were randomly divided into three groups. Patients in Group C (control) received 2 ml of 0.5% of heavy bupivacaine (10 mg) with 0.5 ml of 0.9% saline to a total volume of 2.5 ml, those in Group H (high dose of bupivacaine) received 2 ml of 0.5% of heavy bupivacaine (10 mg) with 1 μg/kg of clonidine and 0.9% saline to make a total volume of 2.5 ml, and those in Group L (low dose of bupivacaine) received 1.5 ml of 0.5% of heavy bupivacaine (7.5 mg) with 1 μg/kg clonidine and 0.9% saline to make a total volume of 2.5 ml. Patients were observed for onset and duration of sensory and motor block and for postoperative analgesia.Results:Patients who received clonidine as adjuvant had effective prolonged postoperative analgesia (Group H – 480 ± 40 min, Group L – 480 ± 34 min) as compared to control group (180 ± 19 min).Conclusion:The dose of intrathecal bupivacaine 0.5% was effectively reduced to 7.5 mg by adding 1 μg/kg of clonidine as adjuvant in patients undergoing elective cesarean section.

Dexmedetomidine as Adjuvant to Lower Doses of Intrathecal Bupivacaine for Lower Limb Orthopedic Surgeries.

Background:Dexmedetomidine, an α2 adrenergic agonist, has been found to be a useful adjuvant to local anesthetics. It has been found to produce satisfactory block with lower doses of spinal bupivacaine.Aim:The aim of this study is to compare the difference in spinal block characteristics and hemodynamic effects of 7, 8, and 9 mg hyperbaric bupivacaine combined with 5 μg dexmedetomidine and to find out the optimum dose that would provide satisfactory block and hemodynamic stability for lower limb orthopedic surgeries.Settings and Study Design:This was a prospective, observational study.Materials and Methods:Ninety patients undergoing lower limb orthopedic surgeries were allocated to three groups of thirty each. Group A received 7 mg, Group B 8 mg and Group C 9 mg 0.5% hyperbaric bupivacaine along with dexmedetomidine 5 μg. The spinal block characteristics, hemodynamic stability, and side effects were compared.Statistical Analysis:The quantitative variables were compared using ANOVA test and the qualitative variables using Chi-square test.Results:All three groups had satisfactory anesthesia and analgesia. The onset of analgesia was slower and peak sensory level lower in Group A. The onset of motor block, time to attain peak sensory levels, duration of analgesia, maximum pain scores, and requirement of rescue analgesics were comparable among groups. Duration of motor block and time of regression of sensory level were more in Group C. Hemodynamics and sedation scores were comparable.Conclusion:Dexmedetomidine with lower doses of bupivacaine produces satisfactory anesthesia without hemodynamic instability. A dose of 7 mg bupivacaine with 5 μg dexmedetomidine may be sufficient for orthopedic surgeries.

Primary Hydromorphone-Related Intrathecal Catheter Tip Granulomas: Is There a Role for Dose and Concentration?

Intrathecal drug delivery therapy has been used effectively in treating patients with intractable chronic pain. The development of an intrathecal catheter tip granuloma (ICTG) related to delivery of intrathecal opiates is a relatively infrequent, but potentially devastating complication. While there are many morphine-related ICTG cases described, reports of hydromorphone-related ICTG are limited. In addition, studies suggest a strong correlation between the use of higher doses and concentrations of intrathecal opiates and ICTG formation. The objective of this study is to determine the incidence and the association of intrathecal hydromorphone dose, concentration, duration of treatment and concomitant agents with ICTG formation. This is a retrospective analysis of 101 consecutive patients implanted with intrathecal infusion delivery devices. Data were collected from chart review, and records of pump refills from the division of Pain Medicine of University Hospitals or outsourced to a home pump refill service. From a cohort of 101 consecutively implanted patients, 69 were treated with intrathecal hydromorphone and followed up postimplant for an average of 33.5 ± 24 months (range 0-93 months; 95% CI of 27-39 months). The incidence of ICTG in our patient population was 8.7% during this period of time postimplant with mean time to granuloma detection 35.1 ± 7.9 months. Patients developing granuloma (n = 6) were treated with a combination of intrathecal hydromorphone and bupivacaine infusion. Exposure time to intrathecal agents was not different between the granuloma and nongranuloma group. Monthly dose increase of hydromorphone was higher in granuloma group vs. non-granuloma group (58 ± 34 mcg/month n = 6 vs. 25 ± 8 mcg/month n = 63). Four out of six granuloma cases occurred with low dose and concentration of IT hydromorphone (160-370 mcg/day; 0.75-1.0 mg/mL concentration). Intrathecal bupivacaine dose was not different between groups. A subset of patients was treated with intrathecal fentanyl and bupivacaine. No intrathecal granulomas occurred in this patient cohort. This is the first clinical report demonstrating an association of hydromorphone with intrathecal granulomas, particularly at low doses and concentrations of hydromorphone. This study supports the notion that using low dose of IT opioids might not protect against ICTG development but that the level of exposure and type of opioid used in IT space might be highly correlated with ICTG development. Further research and recommendations related to chronic intrathecal opioid infusions are necessary to raise awareness of significant incidence of ICTG and development of tests to isolate patient populations at high risk.