A randomized comparison of onset of anesthesia between spinal bupivacaine 5 mg with immediate epidural 2% lidocaine 5 mL and bupivacaine 10 mg for cesarean delivery

BackgroundPrevious studies using low-dose spinal anesthesia for cesarean delivery have focused on hypotension and efficacy. This study evaluated whether, using a combined spinal–epidural technique, there was a difference in onset of anesthesia for cesarean delivery between low-dose spinal with an immediate epidural local anesthetic bolus, and conventional-dose spinal anesthesia.MethodsForty healthy term nulliparous women undergoing elective cesarean delivery with a combined spinal–epidural technique were enrolled into this prospective, randomized, double-blind study. Patients were randomly allocated to the low-dose (Group L) or conventional-dose group (Group C). Patients in Group L received intrathecal isobaric bupivacaine 5 mg with sufentanil 2.5 μg followed by epidural 2% lidocaine 5 mL; patients in Group C received intrathecal isobaric bupivacaine 10 mg with sufentanil 2.5 μg followed by epidural saline 5 mL. The onset of anesthesia (defined as the time from spinal injection to a block to T6), incidence of hypotension, maximal sensory block, epidural supplementation and side effects were recorded.ResultsAll blocks reached T6 within 11 min except for one patient in Group L. There were no differences in onset of anesthesia (9.9 ± 3.2 min in Group L vs. 8.5 ± 1.2 min in Group C, P = 0.08), maximal block level and the number of patients who required epidural supplementation in both groups. Hypotension occurred in 8 patients (40%) in Group L and 15 patients (75%) in Group C (P = 0.02).ConclusionsIntrathecal bupivacaine 5 mg with immediate 2% epidural lidocaine 5 mL provided comparable onset and efficacy of anesthesia as bupivacaine 10 mg with immediate epidural normal saline 5 mL for cesarean delivery.     

A comparison of epidural magnesium and/or morphine with bupivacaine for postoperative analgesia after cesarean section

BackgroundMagnesium can potentiate the antinociceptive effect of morphine. This prospective randomized double-blinded study was undertaken to establish the analgesic effect of adding magnesium to epidural morphine during cesarean section.MethodsTwo hundred patients undergoing cesarean section under combined spinal–epidural anesthesia were recruited. After administration of intrathecal bupivacaine 10 mg, patients were randomly assigned to receive one of four epidural study solutions: 0.1% bupivacaine 10 mL (Group B); 0.1% bupivacaine 10 mL and morphine 1.5 mg (Group B+Mor); 0.1% bupivacaine 10 mL and magnesium 500 mg (Group B+Mg); or 0.1% bupivacaine 10 mL morphine 1.5 mg and magnesium 500 mg (Group B+Mor+Mg). The primary outcome was the area under the curve for visual analog scale pain scores during 36 h postoperatively. Secondary outcomes included time to the use of rescue analgesics, patient satisfaction and side effects.ResultsPatients in Group B+Mor+Mg had lower for pain scores and area under the curve pain scores both at rest and on movement, increased time for first analgesic request, and increased satisfaction score at 24 h after surgery.ConclusionAddition of magnesium 500 mg and morphine 1.5 mg to epidural 0.1% bupivacaine 10 mL reduced postoperative pain compared with addition of morphine or magnesium alone or no additive.     

A comparison between post-operative analgesia after intrathecal nalbuphine with bupivacaine and intrathecal fentanyl with bupivacaine after cesarean section

BackgroundAdding intrathecal opioids to intrathecal local anesthetics to decrease their doses and provide hemodynamic stability are major goals during spinal anesthesia in cesarean section. Different opioids were used to select the one with the longest duration of analgesia and the least side effects. In this study, intrathecal nalbuphine was compared with intrathecal fentanyl as an adjuvant to hyperbaric bupivacaine in cesarean section.Patients and methodsSixty female patients of ASA grades I and II presented for elective cesarean deliveries with spinal anesthesia were randomly allocated to 2 equal groups; Group F: 30 patients received intrathecal injection of 2 ml of 0.5% hyperbaric bupivacaine plus 0.5 ml fentanyl (25 μg); Group N: 30 patients received intrathecal injection of 2 ml of 0.5% hyperbaric bupivacaine plus 0.5 ml nalbuphine (0.8 mg). The onset of sensory and complete motor blockade, time of sensory blockade, duration of analgesia and motor blockade, fetal Apgar score, visual analog scale score, oxygen saturation, adverse effects and hemodynamic parameters were recorded intra-operatively and up to 4 h post-operatively. The effective analgesic time was recorded.ResultsThe onset of complete motor block was significantly more rapid in fentanyl group than in nalbuphine group. The duration of post-operative analgesia was more prolonged in nalbuphine group but the difference was insignificant. No significant difference was found between both groups as regards the duration of sensory block, motor block, duration of analgesia, fetal Apgar score, visual analog scale score, hemodynamic parameters and oxygen saturation. Adverse effects were less common in nalbuphine group but the difference was insignificant.ConclusionEither intrathecal nalbuphine 0.8 mg or intrathecal fentanyl 25 μg combined with 10 mg bupivacaine provides good intra-operative and early post-operative analgesia in cesarean section.     

Neuraxial opioids for post-cesarean delivery analgesia: can hydromorphone replace morphine? A retrospective study

BackgroundCesarean delivery is the most common surgical procedure performed in the USA. We evaluated the postoperative analgesic properties of neuraxial hydromorphone compared to neuraxial morphine for post-cesarean delivery analgesia.MethodsA retrospective chart review was performed of women who underwent cesarean delivery and received neuraxial anesthesia from March to November 2011 and from March to November 2012. A total of 450 patients received intrathecal morphine 200 μg and 387 patients received intrathecal hydromorphone 60 μg. Eighty-one patients received epidural morphine 3 mg and 102 patients received epidural hydromorphone 0.6 mg.ResultsMedian time to first opioid after intrathecal morphine was 17.0 h versus 14.6 h after intrathecal hydromorphone (P <0.0001). Patients who received intrathecal hydromorphone consumed more opioids in the first 24 h; 37.0 mg versus 26.4 mg oral morphine equivalents (P <0.001). The side effect profile between the intrathecal groups was similar. Median time to first opioid with epidural morphine was 20.1 h versus 13.0 h with epidural hydromorphone (P=0.0007). Total opioid consumption was not significantly different between the epidural groups. The side effect profiles were similar.ConclusionsHydromorphone is a reasonable alternative to morphine for post-cesarean delivery analgesia. With the dosing used in our study, analgesia from morphine lasted longer than hydromorphone via intrathecal and epidural routes; however, neuraxial hydromorphone remains a reasonable option for long-acting analgesia post cesarean delivery.     

Evaluation of levobupivacaine passage to breast milk following epidural anesthesia for cesarean delivery

BackgroundFollowing maternal administration, local anesthetics pass into breast milk. In the present study, we aimed to compare the passage of levobupivacaine and bupivacaine into breast milk following epidural anesthesia for cesarean delivery.MethodsA total of 20 women undergoing elective cesarean delivery under epidural anesthesia were randomized to receive either 0.5% levobupivacaine or 0.5% racemic bupivacaine via an epidural catheter. Immediately before and 30 min, 1 h, 2 h, 6 h, 12 h and 24 h after administration of epidural local anesthetic, maternal blood and breast milk samples were taken simultaneously. Drug concentrations in plasma and milk were determined via high-performance liquid chromatography. The infant’s drug exposure was determined by calculating milk/plasma ratios of levobupivacaine and bupivacaine.ResultsBoth levobupivacaine and bupivacaine were detected in breast milk 30 min after epidural administration. Concentrations of both agents showed constant and similar decreases in milk and plasma and were nearly undetectable at 24 h. The milk/plasma ratios were 0.34 ± 0.13 for levobupivacaine and 0.37 ± 0.14 for bupivacaine.ConclusionsBoth levobupivacaine and bupivacaine pass into breast milk following epidural administration. The concentration of both drugs was approximately three times lower in breast milk than in maternal plasma.     

Risk factors for failed conversion of labor epidural analgesia to cesarean delivery anesthesia: a systematic review and meta-analysis of observational trials

BackgroundThis systematic review and meta-analysis evaluates evidence for seven risk factors associated with failed conversion of labor epidural analgesia to cesarean delivery anesthesia.MethodsOnline scientific literature databases were searched using a strategy which identified observational trials, published between January 1979 and May 2011, which evaluated risk factors for failed conversion of epidural analgesia to anesthesia or documented a failure rate resulting in general anesthesia.Results1450 trials were screened, and 13 trials were included for review (n = 8628). Three factors increase the risk for failed conversion: an increasing number of clinician-administered boluses during labor (OR = 3.2, 95% CI 1.8–5.5), greater urgency for cesarean delivery (OR = 40.4, 95% CI 8.8–186), and a non-obstetric anesthesiologist providing care (OR = 4.6, 95% CI 1.8–11.5). Insufficient evidence is available to support combined spinal–epidural versus standard epidural techniques, duration of epidural analgesia, cervical dilation at the time of epidural placement, and body mass index or weight as risk factors for failed epidural conversion.ConclusionThe risk of failed conversion of labor epidural analgesia to anesthesia is increased with an increasing number of boluses administered during labor, an enhanced urgency for cesarean delivery, and care being provided by a non-obstetric anesthesiologist. Further high-quality studies are needed to evaluate the many potential risk factors associated with failed conversion of labor epidural analgesia to anesthesia for cesarean delivery.     

Effects of intravenous ondansetron and granisetron on hemodynamic changes and motor and sensory blockade induced by spinal anesthesia in parturients undergoing cesarean section

BackgroundSpinal anesthesia has many advantages for cesarean section parturients, but hypotension is considered the most frequent complication and can be managed by different interventions. One of these interventions is to give a serotonin receptor antagonist prior to spinal anesthesia.ObjectivesTo compare between two serotonin receptor antagonists on the hemodynamics, sensory, and motor blockade induced by intrathecal bupivacaine in parturients undergoing cesarean section.Patients and methodsSixty patients undergoing elective cesarean section under spinal anesthesia by intrathecal bupivacaine were randomly divided into three groups (20 pregnant females of ASA I–II physical status in each group). Group O received intravenous 4 mg ondansetron diluted in 10 ml normal saline and injected over 1 min, 5 min before spinal anesthesia, group G given intravenous 1 mg granisetron by the same route and group S given 10 ml normal saline. Mean arterial blood pressure, heart rate, vasopressor use, sensory, and motor blockade were assessed.ResultsDecreases in mean arterial pressure were significantly lower in group O than groups G and S with lower vasopressor use (P < 0.05), while there was significant faster sensory recovery in group G than groups O and S (P < 0.05). Actually, there were significant decrease in the incidence of nausea in groups O and G than group S (P = 0.008).ConclusionIn parturient females undergoing elective cesarean section, intravenous 4 mg ondansetron before subarachnoid block significantly decreased both the hypotension and the doses of vasopressor used, while intravenous 1 mg granisetron prior to subarachnoid block induced faster sensory recovery compared to both the ondansetron and the saline groups, with no significant differences between the later two groups.     

Comparison of the ED50 of intrathecal hyperbaric ropivacaine co-administered with or without intrathecal dexmedetomidine for cesarean section: A prospective,double-blinded,randomized dose-response trial using up-down sequential allocation method

Study objectiveStudies have showed that intrathecal dexmedetomidine as supplements to local anesthetics can improve the quality of the spinal anesthesia and reduce the local anesthetic requirement of spinal anesthesia for cesarean section. However, the magnitude of this effect has not been fully quantified. Therefore, we conducted the present study to investigate the ED₅₀ of intrathecal hyperbaric ropivacaine with or without dexmedetomidine for cesarean section in healthy parturients. ED₅₀ values obtained were compared to estimate the effect of intrathecal dexmedetomidine versus placebo on ropivacaine requirement.DesignSingle-blinded, prospective, randomized study.SettingDepartment of Anesthesia, Women's Hospital, Zhejiang University School of Medicine.PatientsSixty healthy parturients under elective cesarean section with combined spinal-epidural anesthesia were randomized into Group C (intrathecal ropivacaine alone) and Group D (intrathecal ropivacaine + 5 μg dexmedetomidine).InterventionsThe dose of intrathecal ropivacaine for the first parturient in both groups was 11 mg. An increment or decrement of 0.5 mg intrathecal ropivacaine was made for the subsequent parturient based on the effective or ineffective response of the previous parturient. Effective dose was defined as a bilateral T6 or above sensory block level was achieved within 15 min after induce of spinal anesthesia and no additional epidural anesthetics was required during surgery. The Dixon and Massay sequential method and Probit regression were applied to calculate the ED₅₀ of intrathecal ropivacaine in both groups.MeasurementsCharacteristics of spinal anesthesia and side effects were recorded.Main resultsThe ED₅₀ of hyperbaric ropivacaine calculated by Dixon and Massay formula was 11.4 mg (95% CI, 11.1–11.7 mg) in Group C, and 9.4 mg (95% CI, 9.0–9.7 mg) in Group D (P < 0.05). While using the Probit regression, the ED₅₀ of intrathecal hyperbaric ropivacaine was 11.1 mg (95% CI, 10.7–11.6 mg) in Group C, and 9.1 mg (95% CI, 8.6–9.5 mg) in Group D. Shivering was less observed in Group D than in Group C (P < 0.05). There was no significant difference in the onset time of sensory block or motor block, the incidence of hypotension, bradycardia, nausea and vomiting, sedation and pruritus between the two groups.ConclusionUnder the conditions of the present study, intrathecal dexmedetomidine (5 μg) reduced the ED₅₀ of intrathecal hyperbaric ropivacaine by approximately 18% for cesarean section in healthy parturients under combined spinal-epidural anesthesia.     

Analgesic requirements and postoperative recovery after scheduled compared to unplanned cesarean delivery: a retrospective chart review

BackgroundStudies examining the effects of various analgesics and anesthetics on postoperative pain following cesarean delivery conventionally use the scheduled cesarean population. This study compares postoperative analgesic requirements and recovery profiles in women undergoing scheduled cesarean compared to unplanned cesarean delivery following labor. We postulated that unplanned cesarean deliveries may increase postoperative analgesic requirements.MethodsWe conducted a retrospective chart review of 200 cesarean deliveries at Lucile Packard Children’s Hospital, California. We examined the records of 100 patients who underwent scheduled cesarean delivery under spinal anesthesia (hyperbaric bupivacaine 12 mg with intrathecal fentanyl 10 μg and morphine 200 μg) and 100 patients that following a trail of labor required unplanned cesarean under epidural anesthesia (10–25 mL 2% lidocaine top-up with epidural morphine 4 mg after clamping of the umbilical cord). We recorded pain scores, analgesic consumption, time to first analgesic request, side effects, and length of hospital stay.ResultsWe found no differences in postoperative pain scores and analgesic consumption between scheduled and unplanned cesarean deliveries for up to five days postoperatively. There were no differences in treatment of side effects such as nausea, vomiting, or pruritus (P > 0.05).ConclusionThe results indicate that women experience similar pain and analgesic requirements after scheduled compared to unplanned cesarean delivery. This suggests that the non-scheduled cesarean population may be a suitable pain model to study pain management strategies; and that alterations in pain management are not necessary for the unplanned cesarean delivery population.     

Pencil-point needle bevel direction influences ED50 of isobaric ropivacaine with fentanyl in spinal anesthesia for cesarean delivery: a prospective,double-blind sequential allocation study

BackgroundThere is little evidence on the influence of bevel direction of a pencil-point needle on the median effective dose (ED50) of isobaric ropivacaine and fentanyl in spinal anesthesia for cesarean delivery.MethodsIn this prospective, double-blind, sequential allocation study, 82 parturients scheduled for elective cesarean delivery under combined spinal-epidural anesthesia were included. We sought to determine the median effective dose of intrathecal 0.75% isobaric ropivacaine plus fentanyl 15 μg with two different bevel directions of a 26-gauge Whitacre needle using up-down sequential allocation. Parturients were randomly allocated to either Group Ce (needle aperture oriented in a cephalad direction) or Group Ca (aperture directed caudally). The initial dose was 0.75% ropivacaine 11.25 mg plus fentanyl 15 μg in both groups. Each dose was classified as effective if, after 15 min and during the next 60 min, there was inability to appreciate pin-prick as sharp at T4, a visual analogue pain score <2 and no requirement for an epidural rescue bolus.ResultsEighty patients were included in the analysis. The ED50 in group Ca was significantly higher (13.09 mg, 95% CI 12.19–14.00) than in group Ce (10.10 mg, 95% CI 9.54–10.65, P <0.001).ConclusionThe orientation of the distal aperture of a 26-gauge Whitacre needle during induction of spinal anesthesia for cesarean delivery influences the ED50 of 0.75% ropivacaine.     

Postural change from lateral to supine is an important mechanism enhancing cephalic spread after injection of intrathecal 0.5% plain bupivacaine for cesarean section

BackgroundSpinal anesthesia is widely used for cesarean section, but the factors that affect the spread of the block in pregnant patients are still not fully explained. This study was designed to investigate the effect of postural changes on sensory block level.MethodsThirty patients scheduled for elective cesarean section under combined spinal–epidural anesthesia were randomly allocated into three groups. After intrathecal injection of 0.5% plain bupivacaine 7.5 mg, patients in group S were immediately placed in the supine position with left tilt, patients in group L5 were kept lateral for 5 min and then turned to the supine position with left tilt, and patients in group L10 were kept lateral for 10 min and then turned to the supine position with left tilt.ResultsAt 5 min, median cephalad level of sensory block was lower in groups L5 and L10 compared with group S (corrected P<0.001); at 10 min, median cephalad sensory block level was lower in group L10 compared with group S (corrected P<0.001) and group L5 (corrected P<0.001), and lower in group L5 compared with group S (corrected P=0.033); at 15 min, median cephalad level of sensory block was lower in group L10 compared with group S (corrected P=0.003) and group L5 (corrected P=0.015).ConclusionsIn our population, using 0.5% plain bupivacaine 7.5 mg, postural change from the lateral position to the supine position is an important mechanism enhancing cephalic spread of spinal anesthesia during late pregnancy.     

Pharmacokinetics of bupivacaine after bilateral ultrasound-guided transversus abdominis plane block following cesarean delivery under spinal anesthesia

BackgroundTransversus abdominis plane block is an effective method of post-cesarean analgesia. There are no data available about plasma bupivacaine levels after this block in adults. This study aimed to assess bupivacaine pharmacokinetic parameters after ultrasound-guided transversus abdominis plane blocks following cesarean delivery under spinal anesthesia.MethodsA prospective observational study in parturients undergoing elective cesarean delivery under hyperbaric bupivacaine spinal anesthesia was conducted. After surgery, patients received bilateral transversus abdominis plane block (50 mg bupivacaine each side). Venous blood samples were collected immediately before performing the block and at 10, 20, 30, 45, 60, 90, 120, 180, 240, 720 and 1440 minutes. High performance liquid chromatography was used to measure total plasma bupivacaine concentrations. Mean bupivacaine area under the curve (AUC) was calculated from 0 to 24 hours.ResultsData were collected from 17 parturients. Mean age and body mass index were 31 ± 6 y and 30 ± 4 kg/m² respectively. Mean plasma bupivacaine concentration before the block was 171 ng/mL. Mean peak concentration was 802.36 ng/mL (range 231.8 to 3504.5 ng/mL). Mean time to peak concentration was 30 min and mean area-under-the-curve (0–24 h) was 4505.4 h.ng/mL. Mean elimination half-life was 8.75 h. Three subjects had concentrations above the quoted toxic threshold and mild symptoms suggestive of neurotoxicity were reported by two subjects, but no treatment was required.ConclusionSingle-dose bilateral transversus abdominis plane block using 100 mg of bupivacaine, after spinal anesthesia for cesarean delivery, can result in toxic plasma bupivacaine concentrations.     

Study of equivalence: spinal bupivacaine 15 mg versus bupivacaine 12 mg with fentanyl 15 μg for cesarean delivery

BackgroundA safe and effective intrathecal dose of bupivacaine alone for cesarean delivery has not yet been established. This study tested the hypothesis that an intrathecal dose of hyperbaric bupivacaine 15 mg would produce equivalent spinal anesthesia for cesarean delivery as the combination of hyperbaric bupivacaine 12 mg and fentanyl 15 μg.MethodsThis was a single center, double-blind, randomized clinical trial of equivalence. One hundred and thirty-eight healthy parturients scheduled for elective cesarean delivery were randomized to receive either intrathecal hyperbaric bupivacaine 15 mg (Group B) or hyperbaric bupivacaine 12 mg with fentanyl 15 μg (Group BF). Parturients where asked to describe their degree of sensation during surgery using a four-point scale 20 min after spinal injection. Secondary outcomes included the incidence of maternal side effects, maternal hemodynamics and the need for supplemental analgesia.ResultsThere was no difference in the quality of anesthesia between the two groups. Sixty-eight of 69 and 69/69 patients in Group B and Group BF, respectively had anesthesia classified as successful (RR = 1.01; 95% CI 0.85, 1.22). The only two secondary outcomes that were different between the groups were the largest change in mean arterial pressure (decrease of 40 mmHg and 34 mmHg for Group B and Group BF, respectively; P = 0.004) and the incidence of nausea (59% and 35% for Group B and Group BF, respectively; P = 0.006).ConclusionThere was no difference in the degree of sensation at 20 min between Group B and Group BF. The only significant differences between the two techniques were a higher incidence of nausea and decrease in maternal blood pressure in Group B.     

Determination of the median effective dose (ED50) of bupivacaine and ropivacaine unilateral spinal anesthesia

Background

Unilateral spinal anesthesia (USpA) has been reported to potentiate spinal anaesthesia and is used in geriatric patients. The purpose of this study was to determine the median effective dose (ED₅₀) of 0.5% hypobaric bupivacaine and 0.5% hypobaric ropivacaine USpA for geriatric patients (age ≥ 70 years) undergoing elective hip replacement surgery.

Methods

A total of 60 geriatric patients (age ≥ 70 years) undergoing elective hip replacement surgery were enrolled in this study. The patients were randomized into 2 groups to receive either intrathecal 0.5% hypobaric bupivacaine USpA (group B) or 0.5% hypobaric ropivacaine USpA (group R). Effective anesthesia was defined as a T10 sensory blockade level maintained for more than 60 min, and a Bromage score of 3 on the operation side within 10 min after injection with no additional epidural anesthetic required during surgery. The ED₅₀ of 0.5% hypobaric bupivacaine and 0.5% hypobaric ropivacaine was calculated using the Dixon and Massey formula.

Results

No significant differences were found between the two groups in terms of demographic data. The ED₅₀ of 0.5% hypobaric bupivacaine USpA was 4.66 mg (95% confidence interval CI 4.69–4.63 mg) mg and that of 0.5% hypobaric ropivacaine USpA was 6.43 mg (95% CI 6.47–6.39 mg) for geriatric patients undergoing hip replacement surgery.

Conclusion

We find the ED₅₀ were lower, and the ED50 of 0.5% hypobaric bupivacaine and ropivacaine was 4.66 mg (95% CI 4.69–4.63 mg) and 6.43 mg (95% CI 6.47–6.39 mg), respectively, for USpA in geriatric patients (age ≥ 70 years) undergoing elective hip replacement surgery.

     

A new modality for improving the efficacy of intrathecal injection for cesarean section

BackgroundIntrauterine resuscitation (IUR) is to improve O2 delivery to the placenta and umbilical blood flow, for reversal of foetal hypoxia and acidosis. We evaluated whether maintaining a lateral position after an intrathecal injection of a relatively low dose of hyperbaric bupivacaine and high dose of fentanyl improving the efficacy of spinal anaesthesia, IUR and preventing hypotension during cesarean delivery.MethodsOne hundred and seventy two healthy women undergoing elective cesarean delivery were enrolled in a double blind prospective randomized study. Spinal anesthesia was conducted in the right lateral position which maintained for 6 min for all the patients participated in the study, and then the subjects were turned supine. Patients were randomly allocated to two groups: low-dose spinal bupivacaine (LD) group (n = 86) patients received 6 mg of hyperbaric bupivacaine 0.5% and 15 μg of fentanyl, high-dose spinal bupivacaine (HD) group (n = 86) patients received 10 mg of hyperbaric bupivacaine and 15 μg of fentanyl. The incidence of hypotension and nausea, ephedrine requirement, maximal block height, and Apgar score at 1 and 5 min.ResultsThe authors found significant decrease in MAP in the group that was given the high dose of bupivacaine the incidence of hypotension was 80% but the LD spinal bupivacaine group was hemodynamically stable. The lowest blood pressure, boluses of inj. ephedrine used, or nausea were more significant in the HD group than in LD group. Onset of hypotension was more rapid (8 ± 3 vs. 16 ± 6 min, P < 0.001), and the sensory block level was more cephalad in HD group than in LD group (T2 [C8–T5] vs. T4 [T1–T6], P = 0.001). Apgar scores did not differ between the groups.ConclusionMaintaining the lateral position for 6 min after an intrathecal injection of a relatively low dose of hyperbaric bupivacaine and high dose of fentanyl resulted in improving the efficacy of spinal anaesthesia, IUR by more gradual and higher cephalad sensory block, without an increase in the incidence of maternal hypotension.     

A comparative study of general anesthesia versus combined spinal–epidural anesthesia on the fetus in cesarean section

BackgroundObstetric anesthesia guidelines recommend regional over general anesthesia for most caesarean sections to decrease the risk for both fetus and mother.Aim of the workTo determine the effects of combined spinal epidural anesthesia and general anesthesia on the newborns and the mother undergoing elective cesarean section.SubjectsA total of 60 consecutive women with uncomplicated singleton pregnancies at term and scheduled to undergo elective cesarean section at Kasr Al-Aini obstetric hospital participated in this prospective study. The women were divided into 2 groups (each 30), a general anesthesia group (A) and combined spinal–epidural anesthesia group (B).MethodsUmbilical artery blood gas analysis and Apgar scores were assessed at 1 and 5 min after delivery in the newborn while systolic and diastolic blood pressure, heart rate, oxygen saturation and (capnography in general anesthesia) were measured preoperative and after 5, 10 and 15 min of induction of anesthesia in the mothers. In addition, the time from induction of anesthesia till delivery of the fetus and duration in operative room were measured.ResultsApgar score recorded statistically significant differences between the 2 groups at 1 min and 5 min, where with combined spinal–epidural anesthesia the Apgar score readings were higher than with general anesthesia. HCO₃ readings showed a statistically significant difference between the 2 groups after 1 and 5 min, where the newborns in general anesthesia group had a statistically significant lower HCO₃ compared to the newborns in combined spinal–epidural group. Patients in general anesthesia group were significantly more tachycardic compared to patients in combined spinal–epidural group.ConclusionCombined spinal–epidural anesthesia is safer on the newborn than general anesthesia regarding the APGAR scores and acid–base balance.     

Observational study of continuous spinal anesthesia with the catheter-over-needle technique for cesarean delivery

BackgroundFew studies have assessed the efficacy and safety of continuous spinal anesthesia in obstetrics, although placement of a catheter in the intrathecal space theoretically offers advantages in these patients.MethodsNinety-two women scheduled for elective cesarean delivery using continuous spinal anesthesia with the catheter-over-needle technique (22- or 24-gauge Spinocath^®) were included in the study. The doses of local anesthetic used, hemodynamic variables, use of ephedrine and other drugs, and incidence of complications such as technical failure and postdural puncture headache (PDPH) were recorded.ResultsThe mean (±SD) dose of hyperbaric bupivacaine used was 8.2 ± 1.8 mg. The incidence of hypotension was 30% and the mean total dose of ephedrine was 4 ± 7 mg. The continuous spinal anesthetic technique failed in 18 women (20%). The overall incidence of post-dural-puncture headache was 29%; 18% of patients with post-dural-puncture headache required a blood patch.ConclusionsCompared to previous reports, the incidence of block failure and PDPH in this study was unacceptably high and therefore the risks of the technique appear to outweigh the advantages of continuous spinal anesthesia in obstetric practice.     

Determination of ED50 of hydromorphone for postoperative analgesia following cesarean delivery

BackgroundMorphine is the most common opioid injected into the intrathecal space for postoperative analgesia following cesarean delivery, but ongoing medication shortages have resulted in limited availability. One proposed morphine alternative is hydromorphone. Studies investigating its use in post-cesarean analgesia are limited. This study was conducted to determine the median effective dose of intrathecal hydromorphone 12 h postpartum.MethodsTwenty healthy women undergoing elective cesarean delivery were recruited into this study. Hydromorphone doses were determined using the up-down sequential method. The study dose of hydromorphone started at 6 μg and was raised or lowered by 2 μg depending on the 12-h efficacy of the preceding participant’s dose. Pain scores of <3/10 were considered successful and the subsequent patient received a lower dose. Participants received 0.5% bupivacaine 12.5 mg, fentanyl 25 μg, and the study dose of hydromorphone as a single intrathecal injection.ResultsTen of 20 participants reported an effective hydromorphone dosage 12 h post-injection. The median effective hydromorphone dosage was 4.6 μg (95% CI 3.72 to 5.48 μg) based on participants’ reported visual analog pain scores of <3/10. No significant side effects or adverse outcomes were observed.ConclusionIntrathecal hydromorphone may be an effective alternative to morphine for post-cesarean pain management. The amount of intrathecal hydromorphone necessary to provide analgesia at 12 h postoperatively may be significantly lower than doses currently in use. Further research should be performed to identify the optimal dose of intrathecal hydromorphone for post-surgical pain relief.     

Comparative dose-response study of hyperbaric ropivacaine for spinal anesthesia for cesarean delivery in singleton versus twin pregnancies

Study objectiveIt is controversial whether local anesthetic dose requirement for spinal anesthesia for cesarean delivery differs between patients with singleton and patients with multiple gestation pregnancies. The aim of this study was to determine and compare the ED₅₀ and ED₉₀ for hyperbaric ropivacaine used for spinal anesthesia for cesarean delivery in patients with singleton pregnancies versus patients with twin pregnancies.DesignProspective, randomized, comparative dose-finding study.SettingOperating room, Women's Hospital, Zhejiang University School of Medicine.Patients100 patients with singleton pregnancies (Group S) and 100 patients with twin pregnancies (Group T) presenting for scheduled cesarean delivery under combined spinal-epidural anesthesia were enrolled in the study.InterventionsPatients in Group S or Group T were randomly allocated to receive 9.5, 11, 12.5, 14 or 15.5 mg of hyperbaric ropivacaine intrathecally. A dose was considered effective when it achieved a bilateral sensory block level at the T6 dermatome or above within 10 min after intrathecal injection, there was no numerical rating scale (NRS) pain score ≥ 3 intraoperatively, and there was no requirement for epidural supplementation at any time during anesthesia and operation. Values for ED₅₀ and ED₉₀ for ropivacaine were determined using probit regression. The difference in ropivacaine dose requirement between patients with singleton pregnancies and patients with twin pregnancies was assessed by calculating relative median potency.MeasurementsSuccess rates for different intrathecal doses of ropivacaine, side effects and neonatal outcomes were recorded.Main resultsThe estimated (95% confidence interval) values for ED₅₀ and ED₉₀ of intrathecal ropivacaine in patients with singleton pregnancies were 11.2 (10.2 to 12.0) mg and 15.7 (14.4 to 18.3) mg, respectively. The values for ED₅₀ and ED₉₀ in patients with twin pregnancies were 10.5 (9.5 to 11.3) mg and 14.8 mg (13.6 to 17.0) mg, respectively. The estimate of relative median potency for ropivacaine between patients with singleton and twin pregnancies was 0.94 (95% confidence interval 0.83 to 1.04).ConclusionPatients with singleton and twin pregnancies have similar dose requirement for hyperbaric ropivacaine used for spinal anesthesia for cesarean delivery in the setting of combined spinal-epidural (CSE) anesthesia, no opioids, low weight cohort, insertion with the patients in the right lateral position, and norepinephrine boluses.     

Epinephrine decreases the dose of hyperbaric bupivacaine necessary for tourniquet pain blockade during spinal anesthesia for total knee replacement arthroplasty

Purpose

We quantified the dose-sparing effect of epinephrine by comparing the median effective dose (ED₅₀) of intrathecal hyperbaric bupivacaine co-administered with epinephrine with the ED₅₀ of intrathecal hyperbaric bupivacaine alone.

Methods

Three groups were randomly generated from 162 patients undergoing total knee replacement arthroplasty under combined spinal and epidural anesthesia: Group B (bupivacaine), Group BE1 (bupivacaine plus epinephrine 100 μg), and Group BE2 (bupivacaine plus epinephrine 200 μg). Each group was further divided by bupivacaine doses of 6, 7, 8, 9, 10, or 11 mg. The anesthesia was defined as successful if a bilateral T12 sensory block occurred within 15 min, and no intraoperative epidural supplement was required. The ED₅₀ and ED₉₅ for successful anesthesia and successful tourniquet pain blockade were determined separately by probit regression analysis.

Results

The ED₅₀ and ED₉₅ of intrathecal hyperbaric bupivacaine for successful anesthesia were not different among the groups: the ED₅₀ values were 7.1 mg [95 % confidence interval (95 % CI) 6.0–8.0 mg] in Group B, 6.2 mg (95 % CI 4.8–7.2 mg) in Group BE1, and 6.3 mg (95 % CI 4.9–7.2 mg) in Group BE2. However, the ED₅₀ and ED₉₅ values for tourniquet pain control were significantly smaller in Groups BE1 and BE2 than in Group B: the ED₅₀ values were 7.2 mg (95 % CI 6.3–7.9 mg), 5.5 mg (95 % CI 4.1–6.3 mg), and 5.3 mg (95 % CI 3.7–6.2 mg) in Groups B, BE1, and BE2, respectively. The incidence of tourniquet pain was significantly lower in Groups BE1 and BE2 than in Group B. The time to patients’ requests for supplemental analgesia was significantly longer in Groups BE1 and BE2 than in Group B.

Conclusions

Intrathecal epinephrine did not decrease the dose of intrathecal hyperbaric bupivacaine required for successful anesthesia. However, it reduced the dose required for tourniquet pain blockade.