Could ephedrine replace meperidine for prevention of shivering in women undergoing Cesarean Section under spinal anesthesia? A randomized study

PurposeTo compare possible unlabeled effect of ephedrine, as shivering prophylaxis, with meperidine during spinal anesthesia for Cesarean Section.MethodsAfter institutional ethical committee approval, 96 parturients scheduled for elective cesarean delivery under spinal anesthesia were randomly allocated according to shivering prophylaxis to receive either 15 mg meperidine (group M, n = 48) or 6 mg ephedrine (group E, n = 48) intravenously before spinal block. Incidence and intensity of shivering as well as side effects of either drug were assessed.ResultsThe incidence shivering in meperidine and ephedrine groups in women undergoing Cesarean Section under spinal anesthesia was comparable (27%, 29% respectively, P = 0.06). Also, intensity of shivering was not different between two groups. Moreover, phenylephrine requirement and incidence of nausea and vomiting were significantly less in ephedrine group (121 ± 2.2% and 4.1% respectively) relative to meperidine group (168 ± 3.2% and 16.6% respectively).ConclusionThe prophylactic use of a low dose ephedrine is effective as meperidine for shivering prophylaxis in women undergoing Cesarean Section under spinal anesthesia as meperidine. Moreover, it is associated with less hypotension, nausea and vomiting.     

The effects of a resistive warming mattress during caesarean section: a randomised,controlled trial

BackgroundThe adverse effects of inadvertent perioperative hypothermia in the surgical population are well established. The aim of this study was to investigate whether a resistive warming mattress would reduce the incidence of inadvertent perioperative hypothermia in patients undergoing elective caesarean section.MethodsA total of 116 pregnant women booked for elective caesarean section were randomised to either intraoperative warming with a mattress or control. The primary outcome was the incidence of inadvertent perioperative hypothermia, defined as a temperature <36.0°C on admission to the recovery room. Shivering in the perioperative period, severity of shivering and the need for treatment, total blood loss, fall in haemoglobin, incidence of blood transfusion, immediate health of baby, and length of hospital stay were also recorded.ResultsThe incidence of inadvertent perioperative hypothermia in the mattress-warmed group was significantly lower than in the control group (5.2% vs. 19.0%, P = 0.043); mean temperatures differed between the two groups, 36.5°C and 36.3°C, respectively (P = 0.046). There was also a significantly lower mean (± SD) haemoglobin change in the mattress-warmed group at −1.1 ± 0.9 g/dL versus −1.6 ± 0.9 g/dL in the control group (P = 0.007). There was no difference in shivering (P = 0.798).ConclusionsA resistive warming mattress reduced the incidence of inadvertent perioperative hypothermia and attenuated the fall in haemoglobin. The use of resistive mattress warming should be considered during caesarean section.     

Factors influencing cesarean delivery operative times: a prospective observational cohort study

BackgroundThis study aimed to determine the distribution of operative delivery times for uncomplicated parturients undergoing elective cesarean delivery with neuraxial anesthesia. A secondary aim was to explore patient and surgical factors associated with longer cesarean delivery times.MethodsA prospective observational study of 331 parturients undergoing elective cesarean delivery with neuraxial anesthesia was conducted. Factors examined included age, body mass index, ethnicity, number of previous cesarean deliveries, stretch mark and scar severity and surgical experience.ResultsOperative times ranged from 13 to 108 min with a mean (SD) of 43.4 (±15.7) min. Only 6 (1.8%) parturients had operative times >90 min and none were converted to general anesthesia. As the number of previous cesarean deliveries increased, the mean operative time increased linearly from 39.5 (±13.0) min in subjects with no previous cesarean deliveries to 52.8 (±18.1) min in subjects with 3 or 4 previous cesarean deliveries (P < 0.0005). For parturients with previous cesarean deliveries, operative times were longer for those with scar scores ?5 than for those with scores <5 (P < 0.01). Stretch mark scores were not associated with operative times. Tubal ligation prolonged the total operative time by a mean of 7 min (P < 0.0005), and attending staff required a mean of 6 more min than residents or fellows (P < 0.01). There was no correlation between operative times, age and body mass index and little variation with ethnicity.ConclusionsThese findings identify previous cesarean deliveries, increased scar intensity, tubal ligation and surgical experience as factors that increase operative times for cesarean delivery. The data also suggest that neuraxial anesthesia lasting 90 min should provide adequate analgesia for most uncomplicated parturients undergoing elective cesarean delivery.     

Prophylactic vs. therapeutic magnesium sulfate for shivering during spinal anesthesia

IntroductionShivering is one of the most common complications of neuraxial blockade. Some patients find shivering sensation worse than surgical pain. Therefore, both prevention and treatment of established shivering should be regarded as clinically relevant intervention in the perioperative period. The aim of our study is to compare the efficacy of magnesium sulfate when used for prevention or treatment of shivering following spinal anesthesia.MethodsIn this prospective, double blind, placebo controlled study, 120 ASA I, II patients undergoing surgery under spinal anesthesia were randomized into 3 groups. Following intrathecal injection, Group P (prophylactic) was given MgSO₄, 50 mg/kg I.V. bolus + 2 mg/kg/h infusion. Group T (therapeutic) was given MgSO₄ 50 mg/kg I.V. bolus as a therapy when shivering occurred. If shivering persisted, they received 25 mg/kg I.V. bolus. Group C (control) received saline at identical times. Meperidine was given as rescue if shivering persisted. Shivering grade 3/4 was regarded as significant. Core temperatures, incidence of shivering, and side effects were recorded.Main resultsTotal incidence of shivering, grade 3/4, was 15% in Group P, 45% in Group T, and 50% in Group C (p < 0.01). Magnesium sulfate significantly reduced the incidence and gain of shivering. The use of rescue meperidine was more in Group P (20%) and Group C (50%) compared to none in Group T (p < 0.05, p < 0.01, respectively). Significant reduction in core temperature occurred in the Mg groups compared to the control group p < 0.05. No correlation was found between patients who shivered and core temperature or ΔT. Hypotension was more frequent in Group P; nausea and vomiting were more in Mg groups than control group p < 0.05.ConclusionFollowing spinal anesthesia, prophylactic MgSO₄ infusion lowered incidence of shivering. When shivering did occur, MgSO₄ proved to be an effective treatment with minimal side effects.     

Anesthetic and obstetric outcomes in morbidly obese parturients: a 20-year follow-up retrospective cohort study

BackgroundIn 1993, Hood and Dewan published the results of a trial comparing obstetric and anesthetic outcomes of 117 morbidly obese parturients with matched controls. The authors demonstrated a higher initial epidural anesthesia failure rate, a higher cesarean delivery rate and an increased risk of obstetric complications. We replicated the previous study to provide updated information on outcomes in the morbidly obese pregnant population. We hypothesized that morbidly obese women would still have higher complication and failure rates compared to matched controls and that general anesthesia would be less commonly used than in the previous study.MethodsThe medical records of 230 patients weighing >136 kg (300 pounds) were compared to matched controls: the next patient delivered by the same obstetrician with a weight <113 kg (250 pounds).ResultsThe mean weight of the morbidly obese group was 53.4 ± 6.6 kg/m² compared to 31.1 ± 5.4 kg/m² in the control group. Fifty percent of morbidly obese women required cesarean delivery compared to 32% of controls (P <0.01). Morbidly obese patients had a longer first stage of labor (P <0.01), larger neonates (P <0.01), and were more likely to have a failed initial neuraxial technique for labor analgesia (P <0.01). The need for a replacement procedure for labor was 17%, significantly less than 20 years ago when 42% of catheters in morbidly obese women failed (P <0.01). Failure rates of neuraxial anesthesia for cesarean delivery were similar between groups. Neuraxial procedure times were greater in morbidly obese parturients (P <0.01). Morbidly obese women were less likely to receive general anesthesia compared to 20 years ago (3% vs. 24%, P <0.01).ConclusionsMorbidly obese parturients are still at increased risk for antenatal comorbidities, failed labor analgesia, longer first stage of labor and operative delivery. Replacement labor epidural catheters and general anesthesia for cesarean delivery are less commonly required anesthetic techniques compared to the original study.     

A randomized study of maternal serum cytokine levels following cesarean section under general or neuraxial anesthesia

BackgroundCytokines are significant mediators of the immune response to surgery and also play a role in parturition. The aim of the study was to investigate the impact of the anesthetic technique for cesarean section on plasma levels of cytokines IL-6 and TNF-α.MethodsThirty-five parturients scheduled for elective cesarean section were randomly assigned to general (n = 18) or neuraxial (n = 17) anesthesia. The general anesthesia group received thiopental 4 mg/kg, succinylcholine 1–1.5 mg/kg and 1% end-tidal concentration of sevoflurane in nitrous oxide and 50% oxygen. The neuraxial anesthesia group received intrathecal 0.5% levobupivacaine 1.8–2.2 mL and epidural fentanyl 1 μg/kg. Blood samples were taken for IL-6 and TNF-α immediately after positioning the parturient on the operating table, after uterine incision and before the umbilical cord clamping and 24 h after surgery (T₁, T₂ and T₃ respectively).ResultsThe two groups did not differ in IL-6 (P = 0.15) or TNF-α (P = 0.73) serum concentrations at any time point. In the general and neuraxial anesthesia groups, IL-6 serum concentrations were significantly higher in the third blood sample, T₃ (12.2 ± 5.0 and 15.2 ± 4.3 pg/mL), than in T₁ (0.41 ± 0.38 and 0.29 ± 0.10 pg/mL) and T₂ (0.37 ± 0.47 and 0.24 ± 0.05) respectively (P < 0.001). Within each group, serum TNF-α concentrations did not differ significantly over time (P = 0.44).ConclusionsUnder the present study design anesthetic technique did not affect IL-6 or TNF-α concentrations in parturients undergoing elective cesarean section. Serum IL-6 levels increased 24 h postoperatively independently of anesthetic technique.     

Serum uric acid as a novel marker for uterine atony and post-spinal vasopressor use during cesarean delivery

IntroductionSerum uric acid is a marker for oxidative stress in preeclampsia. Because oxidative stress can result in diminished uterine contractility and impaired vascular relaxation, we hypothesized that an elevated serum uric acid level in women undergoing neuraxial anesthesia for cesarean delivery would be associated with greater uterine atony, as measured by supplemental uterotonic agent use and blood loss, and less hypotension, as measured by total vasopressor use.MethodsAll records of patients (n = 2527) undergoing cesarean delivery in 2009 were reviewed. Serum uric acid was measured within 24 h of delivery in 509 patients; data from 345 patients with singleton pregnancies undergoing neuraxial anesthesia were analyzed. Demographic data, medical and obstetric history, anesthetic management and peripartum course were evaluated. ANOVA, Chi-square, and multivariate logistic and linear regression analyses were performed.ResultsIncreased serum uric acid correlated positively with preeclampsia and the need for supplemental uterotonic agents (odds ratio 1.53, 95%CI 1.2–2.0, P = 0.002), but not blood loss. The presence of preeclampsia also correlated with greater supplemental uterotonic agent use (P = 0.01). The correlation between serum uric acid and post-spinal vasopressor use (i.e., none, moderate, and high) was of borderline significance (P = 0.05). In patients without diabetes, serum uric acid levels correlated inversely with post-spinal vasopressor use (P = 0.04).ConclusionsElevated serum uric acid in parturients undergoing cesarean delivery with neuraxial anesthesia correlated with increased use of supplemental uterotonic agents and decreased use of post-spinal vasopressors. Further validation of this study is required to determine if serum uric acid in parturients can serve as a reliable predictor for higher and lower occurrences of uterine atony and spinal-induced hypotension, respectively.     

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.     

Role of pleth variability index for predicting hypotension after spinal anesthesia for cesarean section

BackgroundHypotension is frequently observed after spinal anesthesia for cesarean section and can be detrimental to both mother and baby. We investigated the role of the pleth variability index for predicting hypotension after spinal anesthesia for cesarean section.MethodsEighty-five parturients undergoing elective cesarean section under spinal anesthesia were enrolled. We recorded pleth variability index and perfusion index before anesthesia, and blood pressure, heart rate and pulse oxygen saturation before and after anesthesia. The association between baseline pleth variability index and perfusion index with hypotension after spinal anesthesia was explored using multivariate analysis.ResultsHypotension occurred in 42 parturients. Baseline pleth variability index was higher in parturients who experienced hypotension than in those who did not (P < 0.05), although there was no difference in baseline perfusion index. The area under the receiver operating characteristic curve was 0.66 for baseline pleth variability index for the prediction of hypotension (P < 0.05). Baseline pleth variability index was significantly related to the incidence of hypotension (P = 0.017), but was not significantly related to the magnitude of the decrease in systolic blood pressure. Baseline perfusion index was not significantly related to the magnitude of the decrease in systolic blood pressure.ConclusionGreater baseline pleth variability index was associated with hypotension after spinal anesthesia for cesarean section, but may not be a clinically useful predictor.     

Hetastarch co-loading is as effective as pre-loading for the prevention of hypotension following spinal anesthesia for cesarean delivery

BackgroundPre-loading with hetastarch decreases the incidence and severity of hypotension after spinal anesthesia for cesarean delivery. However, pharmacokinetic studies with crystalloid predict that fluid loading should be more efficacious if rapidly administered immediately after induction of spinal anesthesia. The aim of this study was to compare pre- and co-loading of hetastarch for the prevention of hypotension following spinal anesthesia for cesarean delivery.MethodsForty-six healthy term parturients scheduled for cesarean delivery were randomized to receive 500 mL of 6% hetastarch intravenously, either slowly before spinal anesthesia (pre-loading) or as quickly as possible immediately after spinal anesthesia (co-loading). Systolic blood pressure was maintained at or above 90% of baseline with intravenous vasopressor boluses (ephedrine 5 mg/mL + phenylephrine 25 μg/mL). The primary outcome was the volume of vasopressor mix required. Secondary outcomes included blood pressure and heart rate changes, time to first vasopressor use, nausea or vomiting, and neonatal outcomes (umbilical artery and vein pH, Apgar scores).ResultsThe pre-loading group used 3.5 ± 2 mL (mean ± SD) of vasopressor mixture compared with 3.2 ± 3 mL in the co-loading group (P = 0.6). There were no differences in any important maternal hemodynamic or neonatal outcome values between the two study groups.ConclusionHetastarch co-loading is as effective as pre-loading for the prevention of hypotension after spinal anesthesia for cesarean delivery. Surgery need not be delayed to allow a predetermined pre-load to be administered before induction of spinal anesthesia.     

Is this the time for Magnesium sulfate to replace Meperidine as an antishivering agent in spinal anesthesia?

Background & AimShivering is one of the serious complications during spinal anesthesia. Mepreidine is considered the most common drug used for control of shivering. The aim of this study is to detect if Magnesium sulfate can replace Mepreidine, in the prevention of shivering in patients undergoing spinal anesthesia during knee arthroscopy.MethodsThe study included 50 patients scheduled for elective knee arthroscopy, aged 20–50 years under spinal anesthesia. The patients were randomly divided into two equal groups. Patients in Group (M) (n = 25) received single intravenous bolus dose of Meperidine 0.5 mg/kg while patients in group (Mg) (n = 25) received intravenous (IV) MgSO₄ in a dose of 50 mg/kg over 20 min followed by 0.5 mg/kg/min both. The both test drugs were administered after establishment of spinal anesthesia. The incidence and severity of shivering were recorded during the operation and in the recovery room.ResultsShivering occurred in 68% of patients in group (M) when compared to group (Mg) where only 28% suffered from shivering. This difference in % was found to be statistically significant. Regarding the complications, local allergy significantly occurred in group (M) in five patients when compare to one patient in group (Mg). There was no significant difference between group (M) and group (Mg) regarding the body core temperature.ConclusionMgSO₄ was found to be an effective way for the control shivering and it could replace Meperidine in middle age patients under spinal anesthesia.     

The impact of gestational age and fetal weight on the risk of failure of spinal anesthesia for cesarean delivery

BackgroundThere are limited data about spinal dosing for cesarean delivery in preterm parturients. We investigated the hypothesis that preterm gestation is associated with an increased incidence of inadequate spinal anesthesia for cesarean delivery compared with term gestation.MethodsWe searched our perioperative database for women who underwent cesarean delivery under spinal or combined spinal-epidural anesthesia with hyperbaric bupivacaine ⩾10.5 mg. The primary outcome was the incidence of inadequate surgical anesthesia needing conversion to general anesthesia or repetition or supplementation of the block. We divided patients into four categories: <28, 28 to <32, 32 to <37 and ⩾37 weeks of gestation. The chi-square test was used to compare failure rates and a multivariable regression analysis was performed to investigate potential confounders of the relationship between gestational age and failure.ResultsA total of 5015 patients (3387 term and 1628 preterm) were included. There were 278 failures (5.5%). The incidence of failure was higher in preterm versus term patients (6.4% vs. 5.1%, P=0.02). Failure rates were 10.8%, 7.7%, 5.3% and 5% for <28, 28 to <32, 32 to <37 and ⩾37 weeks of gestation, respectively. In the multivariable model, low birth weight (P<0.0001), gestational age (P=0.03), ethnicity (P=0.02) and use of combined spinal-epidural anesthesia (P<0.0001) were significantly associated with failure.ConclusionsAt standard spinal doses of hyperbaric bupivacaine used in our practice (⩾10.5 mg), there were higher odds of inadequate surgical anesthesia in preterm parturients. When adjusting for potential confounders, low birth weight was the main factor associated with failure.     

Efficacy of prophylactic use of hydrocortisone and low dose ketamine for prevention of shivering during spinal anesthesia

BackgroundSpinal anesthesia is commonly associated with shivering. The aim of this study was to compare the efficacy of i.v. hydrocortisone with i.v. low dose ketamine or placebo for prevention of shivering during spinal anesthesia.MethodIn this prospective, randomized, double-blind study, 90 female patients ASA I–II age 30–60 years old, undergoing posterior vaginal repair surgeries under spinal anesthesia with 3 ml heavy bupivacaine 0.5% (15 mg), patients were randomly allocated into one of three groups, (Group S, n = 30) (control) received saline, (Group K, n = 30) received ketamine 0.25 mg kg^?1 or (Group H, n = 30) received hydrocortisone 2 mg kg^?1, the drugs were given i.v. just after spinal anesthesia with recording of vital signs, and core temperature every 15 min intraoperative and every 10 min in recovery room. The incidence and intensity of shivering, number of patients received meperidine, sensory level, motor block grade, and side effects (hypotension, hypertension, tachycardia, nausea and vomiting, sedation and hallucinations) were also recorded.ResultsIncidence of shivering were significantly reduced in k and H groups being 20% and 23.3% respectively compared to S group (p < 0.05). Patients received meperidine to control shivering were significantly low in Groups K and H compared to group S (p < 0.05), with no difference between Groups K and H.ConclusionsThe prophylactic administration of low dose ketamine (0.25 mg kg^?1) and hydrocortisone (2 mg kg^?1) were comparable in reducing the incidence of shivering and both had significant antishivering effect compared to placebo, in female patients under spinal anesthesia for posterior vaginal repair surgeries.     

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.     

Effect of low dose phenylephrine infusion on shivering and hypothermia in patients undergoing cesarean section under spinal anesthesia: a randomized clinical trial

BackgroundShivering is a common complication of spinal anesthesia. Phenylephrine, due to its peripheral vasoconstrictive effect, may limit the core to periphery redistribution of body temperature following spinal anesthesia, and reduce hypothermia and shivering. We hypothesized that prophylactic phenylephrine infusion would reduce shivering and hypothermia in women undergoing cesarean section under spinal anesthesia.MethodsA two-arm randomized, double-blind, placebo-controlled trial in term pregnant patients undergoing cesarean section. In the phenylephrine group (n=75) prophylactic phenylephrine infusion was administered at 25 µg/min immediately after initiation of spinal anesthesia and continued until the end of the operative period. In the placebo group (n=75) a normal saline infusion was administered during the same period. The primary outcome was the incidence of shivering; secondary outcomes were severity of shivering, changes in nasopharyngeal (core) temperature, and incidence of hypotension and bradycardia.ResultsThe incidence of shivering in the phenylephrine and control groups was 24.0% (95% CI 14.3% to 33.7%) and 53.3% (95% CI 42.0% to 64.6%), respectively. The severity of shivering was greater in the control group (P=0.002) and the mean (±SD) end of surgery core temperature was significantly higher in the phenylephrine group (35.84°C ± 0.60) compared with controls (35.61°C ± 0.48) (P=0.009). The incidence of hypotension was higher in controls (53.4% vs. 2.7%; P <0.001) but bradycardia more frequent in group P (P=0.023).ConclusionThe incidence of shivering and degree of hypothermia were significantly reduced by a prophylactic phenylephrine infusion during cesarean section under spinal anesthesia.     

Thermoregulatory effects of spinal and epidural anesthesia during cesarean delivery

Background and Objectives: Hypothermia is likely to develop faster during spinal anesthesia than epidural anesthesia. A natural consequence of the rapid temperature decrease during spinal anesthesia is that the shivering threshold will be reached sooner and that more shivering will be required to prevent further hypothermia. We tested the hypotheses that the onset of hypothermia is more rapid and the onset and intensity of shivering earlier during spinal than epidural anesthesia. Methods: Patients undergoing cesarean delivery were randomly assigned to spinal anesthesia or epidural anesthesia. Spinal anesthesia was induced by injecting 2 mL 0.5% dibucaine into the L4–L5 interspace. Epidural anesthesia was induced with 20 mL 2% mepivacaine injected into the L2–L3 interspace. Thermal comfort and shivering were scored by a blinded observer. Results: Fifteen patients given each type of anesthesia had upper sensory levels ≥T4 dermatome. Sensation was entirely absent from the leg during spinal anesthesia, but lower block levels were near S5 during epidural anesthesia. Tympanic membrane temperatures initially decreased faster during spinal anesthesia, but subsequently decreased at a rate of 0.5°C/h in both groups. The onset and incidence of shivering (detected qualitatively) did not differ significantly between the two groups, but shivering intensity was significantly reduced during spinal anesthesia. Furthermore, the shivering thresholds were 36.4 ± 0.3°C (mean ± SD) during spinal anesthesia versus 37.1 ± 0.4°C in those given epidural anesthesia (P = .006). There were no clinically important differences in thermal comfort with the two kinds of neuraxial anesthesia. Conclusions: We failed to confirm our hypothesis, but for an unexpected reason: Thermoregulation was impaired more by spinal anesthesia than epidural anesthesia. It seems likely that in our patients spinal anesthesia inhibited thermoregulatory control more than epidural anesthesia because it better blocked sensory input from the legs.     

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.     

The effect of bupivacaine with fentanyl temperature on initiation and maintenance of labor epidural analgesia: a randomized controlled study

BackgroundLabor epidural analgesia is highly effective, but can be limited by slow onset and incomplete blockade. The administration of warmed, compared to room temperature, bupivacaine has resulted in more rapid onset epidural anesthesia. We hypothesized that the administration of bupivacaine with fentanyl at 37°C versus 20°C would result in improved initial and ongoing labor epidural analgesia.MethodsIn this prospective, randomized, doubled blinded study, 54 nulliparous, laboring women were randomized to receive epidural bupivacaine 0.125% with fentanyl 2 μg/mL (20 mL initial and 6 mL hourly boluses) at either 37°C or 20°C. Pain verbal rating scores (VRS), sensory level, oral temperature, and side effects were assessed after epidural loading (time 0), at 5, 10, 15, 20, 30, 60 min, and at hourly intervals. The primary outcome was the time to achieve initial satisfactory analgesia (VRS ⩽3). Secondary outcomes included ongoing quality of sensory blockade, body temperature and shivering.ResultsThere were no differences between groups in patient demographics, initial pain scores, cervical dilatation, body temperature or mode of delivery. Epidural bupivacaine at 37°C resulted in shorter mean (±SD) analgesic onset time (9.2 ± 4.7 vs. 16.0 ± 10.5 min, P = 0.005) and improved analgesia for the first 15 min after initial bolus (P = 0.001–0.03). Although patient temperature increased during the study (P < 0.01), there were no differences between the groups (P = 0.09). Six (24%) and 10 (40%) patients experienced shivering in the 37°C and 20°C groups, respectively (P = 0.23).ConclusionsThe administration of epidural 0.125% bupivacaine with fentanyl 2 μg/mL at 37°C versus 20°C resulted in more rapid onset and improved labor analgesia for the first 15 min. There was no evidence of improved ongoing labor analgesia or differences in side effects between groups.     

Assessment of endothelial glycocalyx disruption in term parturients receiving a fluid bolus before spinal anesthesia: a prospective observational study

BackgroundFluid bolus administration is a standard treatment for hypotension. However, the effectiveness of the traditional prophylactic bolus in parturients undergoing spinal anesthesia for cesarean delivery has been questioned. One potential mechanism for the failure of a prophylactic fluid bolus to prevent hypotension is hypervolemia-induced destruction of the endothelial glycocalyx, a structure that plays a vital role in regulating intravascular fluid shifts.MethodsThirty healthy parturients undergoing elective cesarean delivery under spinal anesthesia were recruited. Known endothelial glycocalyx biomarkers, heparan sulfate and syndecan-1 along with atrial natriuretic peptide, were measured before and after a 750-mL crystalloid fluid bolus. Cardiac performance parameters, cardiac index and systemic vascular resistance, were monitored during the fluid bolus using thoracic-impedance cardiography.ResultsA significant increase in both heparan sulfate 96 ng/mg (P=0.0098) and syndecan-1 2.4 ng/mg (P=0.045) were observed after the fluid bolus. There was a non-significant increase in atrial natriuretic peptide 0.6 pg/mg (P=0.293). Cardiac parameters showed a small but significant change; over an average of 15 min, cardiac index increased by 0.1 L/min/m² (P=0.0005) and systemic vascular resistance decreased by 30.7 dyn.s/cm⁵ (P=0.0025).ConclusionsA prophylactic fluid bolus in parturients undergoing spinal anesthesia for cesarean delivery disrupts the endothelial glycocalyx, as noted by a statistically significant increase in post-bolus heparan sulfate and syndecan-1 levels. Although studied in the past, atrial natriuretic peptide could not explain this disruption. Our fluid bolus did not have a clinically relevant effect on cardiac performance.     

Comparison between colloid preload and crystalloid co-load in cesarean section under spinal anesthesia: a randomized controlled trial

BackgroundHypotension is a common problem during spinal anesthesia for cesarean delivery. Intravenous fluid loading is used to correct preoperative dehydration and reduce the incidence and severity of hypotension. Different fluid regimens have been studied but colloid preload and crystalloid co-load have not been compared.MethodsIn this randomized double-blind study, 210 patients scheduled for elective cesarean section under spinal anesthesia were randomly allocated to receive either 6% hydroxyethyl starch 130/0.4 500 mL before spinal anesthesia (colloid preload) or Ringer’s acetate solution 1000 mL administered rapidly starting with intrathecal injection (crystalloid co-load). Maternal hypotension (systolic blood pressure <80% of baseline or <90 mmHg) and severe hypotension (systolic blood pressure <80 mmHg) were treated with 5 and 10 mg ephedrine boluses, respectively. The primary outcome was the incidence of hypotension. Secondary outcomes included the incidence of severe hypotension, total ephedrine dose, nausea and vomiting and neonatal outcome assessed by Apgar scores and umbilical artery blood gas analysis.ResultsData analysis was performed on 205 patients; 103 in the colloid preload group and 102 in the crystalloid co-load group. There were no significant differences in the incidence of hypotension (52.4% vs. 42.2%; P=0.18) or severe hypotension (15.5% vs. 9.8%; P=0.31) between colloid preload and crystalloid co-load groups, respectively. The median [range] ephedrine dose was 5 [0–45] mg in the colloid preload group and 0 [0–35] mg in the crystalloid co-load group (P=0.065). There were no significant differences in maternal nausea or vomiting or neonatal outcomes between groups.ConclusionThe use of 1000 mL crystalloid co-load has similar effect to 500 mL colloid preload in reducing the incidence of hypotension after spinal anesthesia for elective cesarean delivery. Neither technique can totally prevent hypotension and should be combined with vasopressor use.