The effects of prophylactic bolus phenylephrine on hypotension during low-dose spinal anesthesia for cesarean section

BackgroundContinuously infused phenylephrine is frequently used to reduce the incidence of hypotension in women undergoing cesarean section under spinal anesthesia, but less is known about the prophylactic bolus method. We evaluated three prophylactic bolus doses of phenylephrine during low-dose spinal anesthesia for cesarean section.MethodsOne-hundred-and-eighty-four patients were randomized to receive 0.9% saline 2 mL (Control Group) or phenylephrine 1.0 μg/kg (PHE1 Group), 1.5 μg/kg (PHE1.5 Group), or 2.0 μg/kg (PHE2 Group) immediately after induction of combined spinal-epidural anesthesia. Maternal blood pressure and heart rate were recorded at 1-min intervals until delivery. Hypotension, defined as systolic blood pressure <80% of baseline, was treated with rescue doses of phenylephrine 100 μg at 1-min intervals until hypotension resolved. The incidence of nausea, vomiting, bradycardia, and hypertension, as well as Apgar scores and umbilical blood gases, were recorded.ResultsThe incidence of hypotension was 71.7% (33/46) in the Control Group, 68.9% (31/45) in the PHE1 Group, 37.0% (17/46) in the PHE1.5 Group and 45.7% (21/46) in the PHE2 Group (P=0.001). The total rescue dose of phenylephrine was greater in the Control Group than those in the PHE1.5 Group (P <0.05) and PHE2 Group (P <0.05). The incidence of hypertension increased as the dose of prophylactic phenylephrine increased (P <0.001) and was highest in the PHE2 group (37%). Other variables did not differ among the four groups.ConclusionsUnder the conditions of this study, prophylactic bolus injection of phenylephrine 1.5 μg/kg was a suitable alternative method for reducing the incidence of hypotension during low-dose spinal anesthesia for cesarean section.     

The use of phenylephrine to obtund oxytocin-induced hypotension and tachycardia during caesarean section

BackgroundOxytocin causes clinically significant hypotension and tachycardia. This study examined whether prior administration of phenylephrine obtunds these unwanted haemodynamic effects.MethodsForty pregnant women undergoing elective caesarean section under spinal anaesthesia were randomised to receive either an intravenous 50 μg bolus of phenylephrine (Group P) or saline (Group S) immediately before oxytocin (3 U over 15 s). Systolic blood pressure, diastolic blood pressure, mean arterial pressure and heart rate were recorded using a continuous non-invasive arterial pressure device. Baseline values were averaged for 20 s post-delivery. Between-group comparisons were made of the mean peak changes in blood pressure and heart rate, and the mean percentage changes from baseline, during the 150 s after oxytocin administration.ResultsThe mean ± SD peak percentage change in systolic blood pressure was −16.9 ± 2% in Group P, and −19.0 ± 1.9% in Group S and the estimated mean difference was 2.1% (95% CI −3.5% to 7.8%; P=0.44); corresponding changes in heart rate were 13.5 ± 2.3% and 14.0 ± 1.5% and the mean estimated difference was 0.5% (95% CI −6.0% to 5%; P=0.87). The mean percentage change from the baseline measurements during the 150 s period of measurement was greater for Group S than Group P: systolic blood pressure −5.9% vs −3.4% (P=0.149); diastolic blood pressure −7.2% vs −1.5% (P=0.014); mean arterial pressure −6.8% vs −1.5% (P=0.007); heart rate 2.1% vs −2.4% (P=0.033).ConclusionIntravenous phenylephrine 50 μg immediately before 3 U oxytocin during elective caesarean section does not prevent maternal hypotension and tachycardia.     

Randomized double-blind comparison of ephedrine and phenylephrine for management of post-spinal hypotension in potential fetal compromise

BackgroundMost studies comparing phenylephrine and ephedrine have been conducted during elective caesarean sections in healthy mothers with no fetal compromise. The effect of vasopressors on fetal outcome may differ between healthy and compromised fetuses. There has been little research into the effect of phenylephrine and ephedrine, when used for management of post-spinal hypotension in the presence of potential fetal compromise.MethodsHealthy women with a singleton pregnancy undergoing emergency caesarean section for fetal compromise under spinal anaesthesia were studied. One-hundred-and-six consecutive subjects, who developed hypotension after spinal anaesthesia, were randomly allocated to two groups of 53 each, to receive either phenylephrine (Group P) or ephedrine (Group E). For every systolic blood pressure reading <100 mmHg patients received phenylephrine 100 μg or ephedrine 8 mg depending on group allocation. Umbilical blood gas parameters and Apgar scores were recorded.ResultsThere was no statistically significant difference in umbilical arterial pH (P=0.79), umbilical venous pH (P=0.98), other blood gas parameters, incidence of fetal acidosis (P=1.00) and Apgar scores. The number of hypotensive episodes, vasopressor doses for treatment of the first hypotensive episode and the total number of doses used during the study period were comparable. The median [IQR] total number of doses of phenylephrine and ephedrine used before delivery were 2 [1–2] and 2 [1–2], respectively (P=0.67). More patients receiving ephedrine (24.5%) developed tachycardia than those receiving phenylephrine (3.8%) (P=0.004). Bradycardia was more common with phenylephrine, with 39.6% of patients in Group P as compared to only 1.9% of patients in Group E developing a heart rate <60 beats/min after vasopressor administration (P=0.001).ConclusionsBoth phenylephrine 100 μg and ephedrine 8 mg boluses are equally efficacious when treating post-spinal hypotension in the presence of potential fetal compromise. However, phenylephrine may be a better choice in the presence of maternal tachycardia.     

A randomised comparison of bolus phenylephrine and ephedrine for the management of spinal hypotension in patients with severe preeclampsia and fetal compromise

BackgroundStudies in healthy patients undergoing elective caesarean delivery show that, compared with phenylephrine, ephedrine used to treat spinal hypotension is associated with increased fetal acidosis. This has not been investigated prospectively in women with severe preeclampsia.MethodsPatients with preeclampsia requiring caesarean delivery for a non-reassuring fetal heart tracing were randomised to receive either bolus ephedrine (7.5–15 mg) or phenylephrine (50–100 µg), to treat spinal hypotension. The primary outcome was umbilical arterial base excess. Secondary outcomes were umbilical arterial and venous pH and lactate concentration, venous base excess, and Apgar scores.ResultsAmong 133 women, 64 who required vasopressor treatment were randomised into groups of 32 with similar patient characteristics. Pre-delivery blood pressure changes were similar. There was no difference in mean [standard deviation] umbilical artery base excess (−4.9 [3.7] vs −6.0 [4.6] mmol/L for ephedrine and phenylephrine respectively; P=0.29). Mean umbilical arterial and venous pH and lactate concentrations did not significantly differ between groups (7.25 [0.08] vs 7.22 [0.10], 7.28 [0.07] vs 7.27 [0.10], and 3.41 [2.18] vs 3.28 [2.44] mmol/L respectively). Umbilical venous oxygen tension was higher in the ephedrine group (2.8 [0.7] vs 2.4 [0.62]) kPa, P=0.02). There was no difference in 1- or 5-min Apgar scores, numbers of neonates with 1-min Apgar scores <7 or with a pH <7.2.ConclusionsIn patients with severe preeclampsia and fetal compromise, fetal acid-base status is independent of the use of bolus ephedrine versus phenylephrine to treat spinal hypotension.     

Continuous infusion of magnesium–lidocaine mixture for prevention of ventricular arrhythmias during on-pump coronary artery bypass grafting surgery

BackgroundDuring on-pump coronary artery bypass grafting (CABG) surgery, the incidence of reperfusion ventricular fibrillation (VF) is high and post-bypass ventricular arrhythmias are common. Both reperfusion VF and ventricular arrhythmias can cause additional myocardial injury to the already ischemic myocardium. This trial aimed to test the assumption that continuous combined magnesium and lidocaine infusion would be efficient and long lasting for the prevention of post-myocardial vascularization ventricular arrhythmias including VF.MethodsEighty ASA III patients, who were candidates for CABG surgery, were randomly assigned into two groups: Group I (control group, n = 40) and Group II (Group ML, n = 40). After endotracheal intubation, patients of control group were infused with plain normal saline in a volume equivalent to study drugs’ mixture volume. Patients of Group ML were infused with magnesium–lidocaine mixture to achieve a bolus of magnesium sulfate 2 g and lidocaine 100 mg followed by continuous infusion of Mg sulfate 500 mg/h and lidocaine 1 mg/min. The initial cardiac rhythm after aortic cross clamp (ACC) release and the occurrence of post-CPB significant ventricular arrhythmias were recorded.ResultsThe incidences of reperfusion VF and post-CPB ventricular arrhythmias in Group ML were significantly lower than that in control group (22.5% vs. 72.5%) (P < 0.001) and (7.5% vs. 25%) (P < 0.05), respectively. However, in Group ML, this beneficial effect was associated with higher incidence of sinus bradycardia (72.5% vs. 17.5%) and hence pacing needs (22.5% vs. 0.0%) when compared with control group.ConclusionOur study concluded that, during on-pump CABG surgery, the combined administration of magnesium and lidocaine as a bolus dose starting after intubation followed by continuous infusion reduced the incidence of reperfusion VF by 62% and post-CPB ventricular arrhythmias by 70% on expense of increased the incidence of sinus bradycardia and pacing.     

The relationship between body mass index and post-dural puncture headache in obstetric patients

BackgroundDifficult epidural insertion and accidental dural puncture are more likely in the obese pregnant population. Low-level evidence suggests that the risk of post-dural puncture headache declines as body mass index increases.MethodsWe retrospectively reviewed prospective data on 18 315 obstetric epidural and combined spinal–epidural insertions, identifying 125 (0.7%) accidental dural punctures or post-dural puncture headaches between 2007 and 2012. The audit record and patient medical record were examined to determine patient body mass index, headache characteristics and use of a therapeutic epidural blood patch. Women were classified into two groups: non-obese (body mass index <30 kg/m², Group <30) or obese (body mass index ⩾30 kg/m², Group ⩾30). Statistical analysis was by chi-square or Fisher exact tests, with P < 0.05 considered significant.ResultsCompared to Group <30 (n = 65), women in Group ⩾30 (n = 60) did not significantly differ in the incidence of post-dural puncture headache (82% vs 80%, P = 0.83); its intensity (severe 36% vs. 23%, P = 0.34); or the need for epidural blood patch (57% vs. 54%, P = 0.81). Groups also did not differ significantly when confining analysis to those who had a witnessed accidental dural puncture (n = 93) or to women with a body mass index >40 kg/m² (n = 10) vs. Group <30.ConclusionThis retrospective study found no evidence that women of higher body mass index are less likely to develop a post-dural puncture headache or that the characteristics of the headache and use of epidural blood patch were different.     

Autoevaluación de una vía clínica para mejora del proceso quirúrgico carcinoma de recto

ObjectivesTo analyse whether the self-evaluation of a clinical pathway improves the results of rectal cancer (RC) treatment.Patients and methodPatients operated on for RC were divided into 3 groups according to biannual modifications of a clinical pathway analysing several indicators.Results166 patients: Group A: 2002 – 3 n=50, B: 2004 – 5 n=53 and C: 2006 – 7 n=63, without any differences in age, gender or comorbidity. Preoperative study improved with the introduction of CT scan: 76% in Group C vs. 6% in Group A (P<0.001). All Group C tumours were staged using MR, rectal ultrasound or both, compared to 84% in Group A (P<0.001). The rate of abdominal-perineal resections was reduced from 42% (Group A) to 17% (Group C); (P=0.007) and about 48% of surgeons in Group A vs. 94% in the C had a specific activity in coloproctology (P<0.001). The average lymph node count was: Group A=6.2±4.5 vs. 13±6.5 in the C and circumferential margin analysis was reported in 24% of Group A vs. 76% in Group C (P<0.001). Parameters such as perioperative blood transfusion, ICU admission, use of nasogastric tube, early feeding or epidural analgesia also improved progressively. Operative mortality decreased non-significantly to 4.7% and anastomotic leaks from 24% to 9.5% with a reduction in postoperative stay from 15 to 11 days during the period analysed (P=0.029).ConclusionsSeveral indicators have significantly improved in a relatively short period of time due to self-evaluations of the process.     

The effect of intravenous ondansetron on maternal haemodynamics during elective caesarean delivery under spinal anaesthesia: a double-blind,randomised, placebo-controlled trial

BackgroundSpinal anaesthesia for caesarean delivery is frequently associated with adverse effects such as maternal hypotension and bradycardia. Prophylactic administration of ondansetron has been reported to provide a protective effect. We studied the effect of different doses of ondansetron in obstetric patients.MethodsThis prospective double-blind, randomised, placebo-controlled study included 128 healthy pregnant women scheduled for elective caesarean delivery under spinal anaesthesia. Women were randomly allocated into four groups (n = 32) to receive either placebo or ondansetron 2, 4 or 8 mg intravenously before induction of spinal anaesthesia. Demographic, obstetric, intraoperative timing and anaesthetic variables were assessed at 16 time points. Anaesthetic variables assessed included blood pressure, heart rate, oxygen saturation, nausea, vomiting, electrocardiographic changes, skin flushing, discomfort or pruritus and vasopressor requirements.ResultsThere were no differences in the number of patients with hypotension in the placebo (43.8%) and ondansetron 2 mg (53.1%), 4 mg (56.3%) and 8 mg (53.1%) groups (P = 0.77), nor the percentage of time points with systolic hypotension (7.3% in the placebo group and 11.1%, 15.7% and 12.6% in the ondansetron 2, 4 and 8 mg groups, respectively, P = 0.32). There were no differences between groups in ephedrine (P = 0.11) or phenylephrine (P = 0.89) requirements and the number of patients with adverse effects.ConclusionsIn our study, prophylactic ondansetron had little effect on the incidence of hypotension in healthy parturients undergoing spinal anaesthesia with bupivacaine and fentanyl for elective caesarean delivery.     

Antenatal fibrinogen concentrations and postpartum haemorrhage

BackgroundIt is unclear whether antenatal fibrinogen concentrations are associated with postpartum haemorrhage.MethodsThis retrospective study included 871 women with a singleton pregnancy but no known risk factors for postpartum haemorrhage, in whom fibrinogen concentration was measured within the 21 days before delivery. Correlation between antenatal fibrinogen concentrations and estimated blood loss was analysed. We tested the hypothesis that the risk of postpartum haemorrhage was higher in women with antenatal fibrinogen concentrations of <3.3 g/L. Postpartum haemorrhage was defined as an estimated blood loss ⩾700 mL following vaginal delivery and ⩾1000 mL following caesarean delivery.ResultsIn women delivering vaginally (n = 337), estimated blood loss tended to increase with decreasing antenatal fibrinogen concentration (R = −0.107, P = 0.05), median fibrinogen concentration was significantly lower in 69 women with postpartum haemorrhage than in 268 women without postpartum haemorrhage (3.93 vs. 4.18 g/L, P = 0.025), and postpartum haemorrhage occurred significantly more often in women with fibrinogen concentrations <3.3 g/L than in those with concentrations ⩾3.3 g/L (38% [11/29] vs. 19% [58/308], P = 0.018). In women undergoing caesarean delivery (n = 534), median fibrinogen concentration did not differ between those who experienced postpartum haemorrhage (n = 128) and those who did not (n = 406) (4.18 g/L vs. 4.07 g/L, P = 0.43). Antenatal fibrinogen concentrations of <3.3 g/L were not associated with higher rates of postpartum haemorrhage (26% [11/43] vs. 24% [117/491], P = 0.80).ConclusionsAntenatal fibrinogen concentration <3.3 g/L may be a risk factor for postpartum haemorrhage among women following vaginal delivery.     

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.     

Analgesic efficacy of pregabalin in acute postmastectomy pain: placebo controlled dose ranging study

Study objectiveWe hypothesized that oral administration of a single dose of pregabalin 2 hours before modified radical mastectomy (MRM) would produce dose-related reduction in postoperative opioid consumption.DesignProspective randomized controlled clinical trial.SettingPostanesthesia care unit.PatientsOne hundred twenty adult women scheduled for unilateral (MRM) with axillary evacuation.InterventionsPatients were randomized to receive either, placebo capsule, pregabalin 75 mg, pregabalin 150 mg, or pregabalin 300 mg.MeasurementsThe assessment parameters were the postoperative analgesic effect using visual analog scale (VAS) pain scores, the subsequent 24-hour morphine consumption, and the systemic adverse effects of pregabalin doses.Main resultsThe VAS score at rest and movement was significantly decreased only in group P300 and group P150 in comparison to group P0 and group P75 at 0 hour (P < .01).The median (interquartile range) consumption of morphine in the first postoperative 24 hours was significantly decreased in group P300 in comparison to group P0 and group P75 (P300 vs P0: 6.5 [5-6.5] vs 20.5 [15.8-20.5] [P < .001]; P300 vs P75: 6.5 [5-6.5] vs 20 [14-20] [P < .001]), but there was no significant difference between group P300 and group P150. In addition, there was a significant decrease in consumption of morphine in group P150 in comparison to group P0 and group P75 (P150 vs P0: 7 [5-7] vs 20.5 [15.8-20.5] [P < .001]; P150 vs P75: 7 [5-7] vs 20 [14-20] [P < .001]). There were statistical significant increase in dizziness and blurred vision in group P300 in comparison to other groups (P < .05).ConclusionsA single preoperative oral dose of pregabalin 150 mg is an optimal dose for reducing postoperative pain and morphine consumption in patients undergoing MRM.     

A randomised comparison of regular oral oxycodone and intrathecal morphine for post-caesarean analgesia

BackgroundPrimary post-caesarean analgesia based on oral opioid has not been adequately studied. This approach may show a good side-effect profile and high satisfaction and avoid neuraxial complications.MethodsIn a double-blind, double-dummy, placebo-controlled clinical trial 120 women were randomised to receive either sustained-release oral oxycodone 20 mg in the recovery room followed by immediate-release oxycodone 10 mg 6-hourly for the first 24 h (group O) or intrathecal morphine 100 μg at the time of spinal anaesthesia (group I). All women received regular postoperative diclofenac, paracetamol and standardised supplemental analgesia.ResultsOne hundred and eleven women completed the study. The area under the curve for pain scores to 24 h did not differ significantly between groups for pain at rest (P=0.465) or on movement (P=0.533). Numerical pain scores were low and similar, except at rest at 12 h (group I 1 [0-2] vs. group O 2 [1-3]; P=0.030). The time to first analgesic request was similar but additional postoperative analgesics were required more often in group O (82% vs. 63%, P=0.034). Group O more frequently reported high worst pain scores (score 4-10 in 87% vs. 64%, P=0.007). Pruritus was more common and more severe in group I (87% vs. 56%, P=0.001). At 24 h maternal satisfaction with the analgesic regimen was lower in group O (P=0.010).ConclusionOral oxycodone produced comparable postoperative pain relief to intrathecal morphine with a lower incidence of pruritus, but was associated with a lower satisfaction score.     

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.     

A comparative study between propofol and dexmedetomidine as sedative agents during performing transcatheter aortic valve implantation

ObjectiveThe type of sedative drugs could play a major role in providing hemodynamic stability which is crucial during transcatheter aortic valve implantation (TAVI) procedure. The aim of this study is to compare propofol with dexmedetomidine for conscious sedation during TAVI.DesignA prospective randomized pilot study.PatientsFifty patients with a mean age of 74 years, American Society of Anesthesiologists 3-4, complaining from severe aortic stenosis were enrolled in this study to undergo TAVI.InterventionsThe propofol group (group P; n = 25) received a bolus dose of 0.5 mg/kg propofol followed by a continuous intravenous infusion of propofol at a rate of 30 to 50 μg kg^− 1 min^− 1, and the dexmedetomidine group (group D; n = 25) received dexmedetomidine at a loading dose of 1 μg/kg and then a continuous intravenous infusion of dexmedetomidine at a rate of 0.5 μg kg^− 1 h^− 1.MeasurementsHeart rate, mean arterial blood pressure, number of phenylephrine boluses, oxygen saturation, sedation, and satisfaction scores were measured just after the start of infusion of the sedation drugs and at the end of the procedure. Postoperative complications were also recorded.ResultsThere was a statistically significant reduction in the heart rate in group D in comparison to group P where it was 67.28 ± 6.9 beats/min in the first group in comparison to 78 ± 6.9 beats/min in the last one (P < .001). The mean arterial blood pressure was statistically significant lower in group D in comparison to group P (58.12 ± 5.4 mm Hg in group D vs 68.24 ± 11.4 mm Hg in group P; P < .001). Also, the number of phenylephrine boluses was higher in group D than in group P (36.5 ± 7.17 in group D vs 20.6 ± 2.07 in group p; P < .001). No difference between the 2 groups regarding oxygen saturation, sedation, pain, satisfaction scores, and postoperative complications.ConclusionDuring TAVI, dexmedetomidine may be associated with significant hypotension and bradycardia rather than propofol.     

O efeito de epinefrina,norepinefrina e fenilefrina no tratamento da hipotensão pós‐raquianestesia: estudo clínico comparativo

Background and objectivesLimited data are present on safety and efficiency of epinephrine for the prophylaxis and treatment of spinal‐hypotension. This study was conducted to compare the effect of epinephrine with norepinephrine and phenylephrine on the treatment of spinal‐hypotension and ephedrine requirement during cesarean delivery.MethodsOne hundred and sixty parturients with uncomplicated pregnancies undergoing elective cesarean delivery under spinal anesthesia were recruited. They were allocated randomly to receive norepinephrine 5 μg.mL^‐1 (n = 40), epinephrine 5 μg.mL^‐1 (n = 40), phenylephrine 100 μg.mL^‐1 (n = 40) or 0.9% saline infusions (n = 40) immediately after induction of spinal anesthesia. Whenever systolic blood pressure drops to less than 80% of baseline, 5 mg of iv ephedrine was administered as rescue vasopressor. The incidence of hypotension, total number of hypotension episodes, the number of patients requiring ephedrine, the mean amount of ephedrine consumption and side effects were recorded.ResultsThere was no statistically significant difference in incidence of maternal hypotension between groups. The number of patients requiring ephedrine was significantly greater in group saline than in group phenylephrine (p < 0.001). However, it was similar between phenylephrine, norepinephrine, and epinephrine groups. The mean ephedrine consumption was significantly higher in group saline than in norepinephrine, epinephrine, phenylephrine groups (p = 0.001).ConclusionThere is no statistically significant difference in incidence of hypotension and ephedrine consumption during spinal anesthesia for cesarean delivery with the use of epinephrine when compared to norepinephrine or phenylephrine. Epinephrine can be considered as an alternative agent for management of spinal hypotension.     

Comparative study on the manually-controlled variable-rate versus fixed-rate infusion of norepinephrine for preventing hypotension during spinal anesthesia for cesarean delivery

Study objectivePrevious studies have shown that prophylactic norepinephrine infusion is superior to intermittent bolus administration in preventing post-spinal hypotension. Nevertheless, it is still controversial whether manually-controlled variable-rate infusion is more effective than fixed-rate infusion. The purpose of the present study was to compare the efficacy of variable-rate infusion and fixed-rate infusion of norepinephrine for prophylaxis against maternal hypotension and maintaining hemodynamic stability during spinal anesthesia for cesarean delivery to determine more effective mode for clinical practice.DesignA prospective randomized, controlled study.SettingOperating room, Women's Hospital, Zhejiang University School of Medicine.PatientsA total of 161 parturients scheduled for elective cesarean delivery with spinal anesthesia were randomized into Group F (fixed-rate infusion) and Group V (variable-rate infusion).InterventionsParturients received prophylactic norepinephrine infusion concurrent with the intrathecal injection at rate started at 0.05 μg/kg/min. In Group F, norepinephrine was administered continuously at a fixed (on-off) rate, and a bolus of norepinephrine 5 μg or 10 μg was given when systolic blood pressure (SBP) decreased by 20% or more of baseline. In Group V, manually adjusted norepinephrine infusion within the range 0–0.14 μg/kg/min, according to SBP at 1-min intervals until delivery, aim to maintain values close to the baseline.MeasurementsDuring the study period, the incidence of maternal hypotension, hemodynamic performance, the number of physician interventions, reactive hypertension, bradycardia, nausea, vomiting, norepinephrine cumulative dose (before delivery), and neonatal outcomes were recorded.Main resultsThe incidence of maternal hypotension was significantly lower in Group V than that in Group F (9% versus 30%) (P < 0.001). No significant difference was found in the serial changes in SBP and heart rate (HR) for the first 15 min. Group V showed higher frequency of physician interventions compared with the Group F (P < 0.001). The incidence of hypertension, severe hypotension, nausea, vomiting, bradycardia, norepinephrine cumulative dose, and neonatal outcome were comparable between the two groups.ConclusionWhen norepinephrine was infused at an initial dose of 0.05 μg/kg/min for preventing hypotension during spinal anesthesia for cesarean delivery, due to technical limitations of inadequate dose design in this study, neither a variable-rate infusion (need more physician intervention) nor a fixed-rate infusion regimen (experience more transient hypotension) was optimal. However, in terms of clinical importance, how to prevent the parturients from experiencing more incidence of hypotension might be a greater concern for anesthesiologists.     

Lidocaine-tramadol versus lidocaine-dexmedetomidine for intravenous regional anesthesia

BackgroundIntravenous regional anesthesia (IVRA) has been used for more than a century. Both tramadol (synthetic opioid) and dexmedetomidine (α₂-agonist) can act locally.Aim of the workTo compare effects of adding tramadol versus dexmedetomidine to lidocaine during IVRA.Patients and methodsSixty patients were randomly assigned into: Group C (n = 20), Group T (n = 20), and Group D (n = 20). All patients received 3 mg/kg 0.5% lidocaine [+100 mg tramadol in Group T, or 1 μg/kg dexmedetomidine in Group D]. Times of onset and offset of sensory and motor blocks, and time to tourniquet pain were recorded. Postoperative VAS score, time to first dose, and total amounts of supplementary analgesia (Paracetamol) were recorded. Sedation was evaluated using Ramsay sedation scale (RSS).ResultsSignificantly shorter onset times and longer recovery times of sensory and motor block were recorded in Groups T and D compared to Group C (P < 0.05); while, with no significant differences between Groups T and D. Delayed onset of tourniquet pain occurred in Groups T and D compared to Group C (P < 0.05) with no significant differences between Groups T and D. Fourteen patients required fentanyl to control tourniquet pain in Group C compared to (5 and 4) in Groups T and D respectively. Significantly lower Postoperative VAS score, longer time to first dose and lower consumption of Paracetamol were recorded in Groups T and D than in Group C; with no significant differences between Groups T and D. Complications were skin rash in 30% of patients in Group T, bradycardia and sedation in 35% and 65% of patients in Group D respectively.ConclusionAddition of either tramadol or dexmedetomidine enhances lidocaine during IVRA with higher incidence of skin rash with tramadol and postoperative bradycardia and sedation with dexmedetomidine.     

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.     

Remifentanil versus placebo for analgesia during external cephalic version: a randomised clinical trial

BackgroundBreech presentation occurs in up to 3% of pregnancies at term and may be an indication for caesarean delivery. External cephalic version can be effective in repositioning the fetus in a cephalic presentation, but may be painful for the mother. Our aim was to assess the efficacy of remifentanil versus placebo for pain relief during external cephalic version.MethodsA randomized, double-blind, controlled trial that included women at 36–41 weeks of gestation with non-cephalic presentations was performed. Women were randomized to receive either a remifentanil infusion at 0.1 μg/kg/min and demand boluses of 0.1 μg/kg, or saline placebo. The primary outcome was the numerical rating pain score (0–10) after external cephalic version.ResultsSixty women were recruited, 29 in the control group and 31 in the remifentanil group. There were significant differences in pain scores at the end of the procedure (control 6.5 ± 2.4 vs. remifentanil 4.7 ± 2.5, P = 0.005) but not 10 min later (P = 0.054). The overall success rate for external cephalic version was 49% with no significant differences between groups (remifentanil group 54.8% vs. control group 41.3%, P = 0.358). In the remifentanil group, there was one case of nausea and vomiting, one of drowsiness and three cases of fetal bradycardia. In the control group, there were three cases of nausea and vomiting, one of dizziness and nine cases of fetal bradycardia.ConclusionIntravenous remifentanil with bolus doses on demand during external cephalic version achieved a reduction in pain and increased maternal satisfaction. There were no additional adverse effects, and no difference in the success rate of external cephalic version or the incidence of fetal bradycardia.     

Neonatal effects after vasopressor during spinal anesthesia for cesarean section: a multicenter,randomized controlled trial

BackgroundPlacental transfer of ephedrine causes fetal effects when compared with phenylephrine. This study compared their drug effects on neonatal parameters after cesarean delivery under spinal anesthesia.MethodsThree-hundred-and-fifty-four women undergoing elective cesarean delivery who needed intravenous vasopressor following spinal anesthesia were randomized into two groups. Group E received boluses of ephedrine 6 mg, and Group P phenylephrine 100 µg, titrated to maintain systolic blood pressure near baseline values. Neonatal heart rates at 10 and 30–45 min of age, oxygen saturation and capillary blood glucose at 30 min, and capillary blood lactate and urine metamphetamine were recorded.ResultsNeonatal heart rate at 10 min was significantly higher (mean difference 4.0, 95%CI 0.6 to 7.3, P=0.02) in Group E versus Group P, but this was not clinically relevant. There was a linear correlation between neonatal heart rate at 10 min and ephedrine dose in Group E (r²=0.29, 95%CI 0.22, 0.74, p <0.01). The decremental changes in neonatal heart rate at 10 and 30 min were significantly greater in Group E. Urine metamphetamine tests were positive in 19% of 44 neonatal urine samples. Neonatal heart rates at 30 min, oxygen saturation, capillary blood glucose and the incidence of tachycardia, respiratory problems or abnormal glucose, were not significantly different.ConclusionsEphedrine, compared to phenylephrine as a vasopressor during cesarean delivery, was associated with higher neonatal heart rate in the early post-birth period, but without a significant difference in clinical outcomes in uncomplicated pregnancies.