Optimal intrathecal hyperbaric bupivacaine dose with opioids for cesarean delivery: a prospective double-blinded randomized trial

BackgroundSingle-shot spinal anesthesia is commonly used for cesarean delivery. Achieving adequate anesthesia throughout surgery needs to be balanced with associated complications. We investigated the optimal dose of intrathecal hyperbaric bupivacaine, co-administered with opioids, for anesthesia for cesarean delivery.MethodsThis prospective, randomized, double-blinded, dose-ranging trial included parturients scheduled to undergo cesarean delivery under spinal anesthesia. An epidural catheter was first inserted at the T11–12 vertebral interspace, followed by spinal anesthesia at the L2–3 or L3–4 vertebral interspace. Subjects were randomly assigned to one of seven doses of intrathecal hyperbaric bupivacaine 0.5% (6, 7, 8, 9, 10, 11 or 12 mg), with added 15 μg fentanyl and 75 μg morphine. Successful induction of anesthesia (success_ind) was defined as achievement of bilateral sensory loss to cold at the T6 dermatome or higher, within 10 minutes. Successful maintenance of anesthesia (success_main) was defined by no epidural supplementation within 60 minutes of intrathecal injection. The effective doses for 50% (ED₅₀) and 95% (ED₉₅) of patients were estimated using logistic regression analysis.ResultsThe ED₅₀ and ED₉₅ for success_main were 6.0 mg (95% CI: 4.5 to 7.5 mg) and 12.6 mg (95% CI: 7.9 to 17.2 mg), respectively. The incidence of respiratory discomfort and maternal satisfaction scores did not differ significantly between dose groups. Phenylephrine dose and nausea/vomiting incidence increased with increasing doses of bupivacaine.ConclusionUnder study conditions, our results suggest that 12.6 mg of intrathecal bupivacaine, administered with fentanyl and morphine, is required to achieve adequate intraoperative analgesia without the need for epidural supplemention.     

An open-label randomized controlled clinical trial for comparison of continuous phenylephrine versus norepinephrine infusion in prevention of spinal hypotension during cesarean delivery

BackgroundDuring spinal anesthesia for cesarean delivery phenylephrine is the vasopressor of choice but can cause bradycardia. Norepinephrine has both β- and α-adrenergic activity suitable for maintaining blood pressure with less bradycardia. We hypothesized that norepinephrine would be superior to phenylephrine, requiring fewer rescue bolus interventions to maintain blood pressure.MethodsEighty-five parturients having spinal anesthesia for elective cesarean delivery were randomized to Group P (phenylephrine 0.1 μg/kg/min) or Group N (norepinephrine 0.05 μg/kg/min) fixed-rate infusions. Rescue bolus interventions of phenylephrine 100 μg for hypotension, or ephedrine 5 mg for bradycardia with hypotension, were given as required to maintain systolic blood pressure. Maternal hemodynamic variables were measured non-invasively.ResultsThere was no difference between groups in the proportion of patients who required rescue vasopressor boluses (Group P: 65.8% [n=25] vs. Group N: 48.8% [n=21], P=0.12). The proportion of patients who received ⩾1 bolus of phenylephrine was similar between groups (Group P: 52.6% [n=20] vs. Group N: 46.5% [n=20], P=0.58). However, more patients received ⩾1 bolus of ephedrine in the phenylephrine group (Group P: 23.7% [n=9] vs. Group N: 2.3% [n=1], P <0.01). The incidence of emesis was greater in the phenylephrine group (Group P: 26.3% vs. Group P: 16.3%, P <0.001). Hemodynamic parameters including heart rate, the incidence of bradycardia, blood pressure, cardiac output, cardiac index, stroke volume, and systemic vascular resistance and neonatal outcome were similar between groups (all P <0.05).ConclusionNorepinephrine fixed-rate infusion has efficacy for preventing hypotension and can be considered as an alternative to phenylephrine.     

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.     

Ultra-low dose combined spinal-epidural anesthesia with intrathecal bupivacaine 3.75 mg for cesarean delivery: a randomized controlled trial

BACKGROUND: We wished to investigate the feasibility of an ultra low-dose combined spinal-epidural technique in providing surgical anesthesia for uncomplicated cesarean deliveries in a randomized, double-blind controlled trial. METHOD: Forty-four normotensive, non-obese patients were randomized to receive either intrathecal hyperbaric bupivacaine 3.75 mg (low dose group, n=22) or 9 mg (conventional group, n=22), in addition to intrathecal fentanyl 25 microg, morphine 100 microg, and epidural 1.5% lidocaine 3 mL. Sensorimotor anesthesia and hemodynamic data were assessed at 2.5-min intervals for the first 15 min. RESULTS: The maximal sensory block achieved in the low-dose group was significantly lower than that in the conventional group (median T3, [range T2-T6] vs. T2 [C2-T6], P<0.001) with a longer time taken to reach maximal sensory block. The low-dose group had less motor block, faster sensory regression to T10 dermatome and faster motor recovery to Bromage 0 (all P<0.001). The block failed to reach T6 bilaterally within 10 min in one patient in the low-dose group and two in the conventional group, with no significant difference in the need for epidural supplementation before or after delivery of the baby. The low-dose group experienced less hypotension (14% vs. 73%, P<0.001) with less ephedrine usage (0.68 vs. 17.5 mg, P<0.001). There was no difference in operating conditions and other side effects (shivering, pruritus). CONCLUSION: We conclude that this technique results in a significantly lower incidence of maternal hypotension and has a role in high-risk parturients in whom maintenance of stable hemodynamics is imperative.     

Prophylactic glycopyrrolate prevents bradycardia after spinal anesthesia for Cesarean section: a randomized, double-blinded, placebo-controlled prospective trial with heart rate variability correlation

Study Objective

To determine if prophylactic glycopyrrolate prevents bradycardia after spinal anesthesia.

Design

Prospective, randomized, double-blinded, placebo-controlled study.

Setting

Large university-affiliated community hospital.

Patients

81 consecutive term parturients (not in active labor) who were scheduled for elective Cesarean section.

Interventions

Parturients received 1.0 to 1.5 L of intravenous Ringer's lactate and either glycopyrrolate 0.4 mg or an equal volume of saline, with caregivers blinded to the immediate sequelae of study drug. Each patient received intrathecal bupivacaine (12 to 14 mg) with morphine sulfate (0.1 to 0.2 mg).

Measurements

Continuous heart rate (HR) and blood pressure monitoring occurred for 20 minutes, with the minimum HR recorded for each 5-minute epoch. Heart rates < 60 beats per minute defined bradycardia. Heart rate variability (HRV) analysis occurred offline.

Main Results

None of 34 patients administered glycopyrrolate and 6 of 35 (17%) patients receiving saline experienced bradycardia (P = 0.02476). Time domain, frequency domain, and nonlinear and embedded spectrum entropy analyses all reflected the decrease in HRV accompanying administration of glycopyrrolate.

Conclusion

Bradycardia after spinal anesthesia occurs commonly. Prophylactic glycopyrrolate may prevent the bradycardia, but not necessarily the hypotension.     

Performance of non-invasive stroke volume variation during passive leg raising as a predictor of hypotension following induction of spinal anesthesia for elective cesarean delivery: a single cohort study

BackgroundSpinal anesthesia for cesarean delivery is accompanied by hypotension in up to 70% of cases. To date, there is no gold standard for predicting hypotension after spinal anesthesia for cesarean delivery. The Clearsight™ device is a non-invasive system that uses a digital cuff to calculate stroke volume. We hypothesized that stroke volume variation induced with passive leg raising before spinal anesthesia for elective cesarean delivery could predict the occurrence of hypotension.MethodsWe conducted a prospective observational study, including third trimester parturients undergoing elective cesarean delivery with spinal anesthesia. We analyzed the stroke volume variation performance for predicting hypotension. Stroke volume was collected in the semi-recumbent position (baseline) and during passive leg raising before spinal anesthesia. Systolic arterial blood pressure measurement was followed for 15 min after spinal anesthesia. Hypotension was defined as a ≥20% decrease from the baseline measurement. All parturients received appropriate hypotension prophylaxis.ResultsData from 42 parturients were analyzed. Hypotension occurred in 45%. The area-under-the curve for predicting hypotension using the stroke volume variation was 0.83 (95% CI 0.68 to 0.98; P=0.001). The best cut-off value for predicting hypotension was 7%, having a sensitivity of 87% (95% CI 0.70 to 0.99) and a specificity of 83% (95% CI 0.69 to 0.97).ConclusionIn our study of third trimester parturients undergoing cesarean delivery and receiving appropriate hypotension prophylaxis, a digital non-invasive monitoring device of stroke volume variation analysis was useful for predicting the occurrence of hypotension after spinal anesthesia.     

Hemodynamic effects of a right lumbar-pelvic wedge during spinal anesthesia for cesarean section

Background

Aortocaval compression is a major cause of maternal hypotension. A randomized controlled trial was designed to determine the effectiveness of a mechanical intervention using a right lumbar–pelvic wedge in preventing hypotension after spinal anesthesia for cesarean delivery.

Methods

Eighty healthy women undergoing elective cesarean section were randomly allocated immediately after spinal blockade to either a lumbar–pelvic wedge positioned under the right posterior–superior iliac crest (Wedge group, n = 40) or the complete supine position (Supine group, n = 40). Hemodynamic values, vasopressor consumption and adverse effects were collected during the surgical procedure. Hypotension was defined as a reduction in systolic blood pressure of 25% from baseline. Patient allocation, management and data collection were performed by a single unblinded anesthetist.

Results

There was no difference in the incidence of hypotension between the two groups (42.5% vs. 50%, P = 0.51). During the first 5 min, blood pressure decreased less in the Wedge group. There were significant differences in median [interquartile range] vasopressor requirements between the Wedge group and the Supine group (1 [0–2] vs. 3 [1–4] mg, P < 0.01) and in nausea during the procedure (6 vs. 22 patients, P < 0.01).

Conclusion

In our study population the use of right lumbar–pelvic wedge was not effective in reducing the incidence of hypotension during spinal anesthesia for cesarean section. Patients in whom the wedge was used had higher systolic blood pressure values during the first 5 min of anesthesia and fewer episodes of nausea. The risk of hypotension remains substantial.     

A randomized trial to investigate needle redirections/re-insertions using a handheld ultrasound device versus traditional palpation for spinal anesthesia in obese women undergoing cesarean delivery

BackgroundUltrasound may be useful to identify the spinal anesthesia insertion point, particularly when landmarks are not palpable. We tested the hypothesis that the number of needle redirections/re-insertions is lower when using a handheld ultrasound device compared with palpation in obese women undergoing spinal anesthesia for cesarean delivery.MethodsStudy recruits were obese (body mass index (BMI) >30 kg/m²) women with impalpable bony landmarks who were undergoing spinal anesthesia for elective cesarean delivery. Women were randomized to ultrasound or palpation. The primary study outcome was a composite between-group comparison of total number of needle redirections (any withdrawal and re-advancement of the needle and/or introducer within the intervertebral space) or re-insertions (any new skin puncture in the same or different intervertebral space) per patient. Secondary outcomes included insertion site identification time and patient verbal numerical pain score (0–10) for comfort during surgical skin incision.ResultsForty women completed the study. The mean BMI (standard deviation) for the ultrasound group was 39.8 (5.5) kg/m² and for the palpation group 37.3 (5.2) kg/m². There was no difference in the composite primary outcome (median (interquartile range) [range]) between the ultrasound group (4 (2–13) [2–22]) and the palpation group (6 (4–10) [1–17]) (P=0.22), with the 95% confidence interval of the difference 2 (−1.7 to 5.7). There were no differences in the secondary outcomes.ConclusionsHandheld ultrasound did not demonstrate any advantages over traditional palpation techniques for spinal anesthesia in an obese population undergoing cesarean delivery, although the study was underpowered to show a difference.     

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.     

Ephedrine versus ondansetron in the prevention of hypotension during cesarean delivery: a randomized,double-blind,placebo-controlled trial

BackgroundMaternal hypotension is common after spinal anesthesia for cesarean delivery. We compared the effects of prophylactic ephedrine with ondansetron on post-spinal blood pressure.MethodsOne hundred and sixty-eight term, singleton parturients were enrolled in this prospective, double-blind, placebo-controlled trial. Patients were randomized to receive either prophylactic intravenous ephedrine 10 mg (Group E), ondansetron 8 mg (Group O) or normal saline (Group P) immediately after spinal anesthesia. The primary outcome was maternal blood pressure between spinal block and delivery; secondary outcomes were nausea and vomiting scores, Apgar scores, numbers requiring intraoperative vasoconstrictors and the dose of vasoconstrictors required.ResultsFifty-six patients were recruited to each group, but two in Group P were excluded from the analysis owing to protocol violations. There were no significant differences between the groups in maternal systolic, diastolic or mean arterial pressures, or the proportion of patients experiencing hypotension. The proportion of patients in Group E requiring intraoperative ephedrine or any vasoconstrictor (ephedrine and/or norepinephrine) was significantly lower than that in Group P (P=0.023 and 0.034, respectively). The proportion of patients in Group O requiring intraoperative norepinephrine was significantly lower than that in Group P (P=0.02). There was no difference in the proportions of patients in Groups E and O requiring any vasoconstrictors (P=0.34).ConclusionsThere was no significant difference in maternal blood pressure in women administered prophylactic ephedrine or ondansetron after spinal anesthesia for cesarean delivery compared with placebo. Ephedrine reduced the proportion of patients requiring a rescue vasoconstrictor before delivery.     

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.     

The effect of baricity of intrathecal bupivacaine for elective cesarean delivery on maternal cardiac output: a randomized study

BackgroundHemodynamic instability during spinal anesthesia for cesarean delivery is associated with adverse maternal and fetal outcomes. Plain and hyperbaric bupivacaine are commonly used for cesarean delivery, however, their distinctive pharmacologic properties may affect maternal hemodynamic profiles differently. The aim of this study was to compare hemodynamic profiles using a suprasternal Doppler cardiac output (CO) monitor in healthy term parturients randomized to receive plain or hyperbaric bupivacaine for cesarean delivery.MethodsOne hundred-and-sixty-eight healthy parturients scheduled for elective cesarean delivery were randomly assigned to receive 10.9 mg of intrathecal 0.5% plain or hyperbaric bupivacaine, both with 0.2 mg morphine. The primary outcome was CO change after spinal anesthesia. Secondary outcomes were the incidence of hypotension, vasopressor use, and conversion to general anesthesia.ResultsThe mean (±SD) CO at baseline, 1 min and 5 min after spinal anesthesia, and after placental delivery was 4.6 ± 1.2, 5.4 ± 1.3, 5.1 ± 1.4, and 6.4 ± 1.7 L/min in the plain bupivacaine, and 4.5 ± 1.1, 5.2 ± 1.3, 4.9 ± 1.3, and 6.2 ± 1.9 L/min in the hyperbaric bupivacaine group. There were no significant differences in CO, mean arterial pressure, or systemic vascular resistance. Incidences of hypotension, vasopressor and supplemental analgesic use, and conversion to general anesthesia, were not different between groups.ConclusionsCardiac output changes after plain or hyperbaric bupivacaine were not different in term parturients undergoing spinal anesthesia for cesarean delivery. Further studies comparing block quality and the rate of conversion to general anesthesia are required.     

General anesthesia for cesarean delivery and childhood neurodevelopmental and perinatal outcomes: a secondary analysis of a randomized controlled trial

BackgroundIn 2016, the U.S. Food and Drug Administration expressed concern that neurodevelopment may be negatively affected by anesthesia or sedation exposure in pregnancy or before three years of age. We examined the association between general anesthesia at the time of cesarean delivery and early childhood neurodevelopment.MethodsA secondary analysis of a multicenter randomized controlled trial assessing magnesium for prevention of cerebral palsy in infants at risk for preterm delivery. Exposure was general compared to neuraxial anesthesia. The primary outcome was motor or mental delay at two years of age, assessed by Bayley Scales of Infant Development II (BSIDII). Secondary outcomes included BSIDII subdomains and perinatal outcomes. Multivariable logistic regression models were performed to control for confounders.ResultsOf 557 women undergoing cesarean delivery, 119 (21%) received general anesthesia. There were no differences in the primary composite outcome of developmental delay (aOR 0.93, 95% CI 0.61 to 1.43) or the BSIDII subdomains of mild, moderate, or severe mental delay, or mild or moderate motor delay. Severe motor delay was more common among infants exposed to general anesthesia (aOR 1.98, 95% CI 1.06 to 3.69). Infants exposed to general anesthesia had longer neonatal intensive care stays (51 vs 37 days, P=0.010).ConclusionsGeneral anesthesia for cesarean delivery was not associated with overall neurodevelopmental delay at two years of age, except for greater odds of severe motor delay. Future studies should evaluate this finding, as well as the impact on neurodevelopment of longer or multiple anesthetic exposures across all gestational ages.     

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.     

Mild induced hypothermia and coagulation and platelet function in patients with septic shock: Secondary outcome of a randomized trial

Coagulation abnormalities and microthrombi contribute to septic shock, but the impact of body temperature regulation on coagulation in patients with sepsis is unknown. We tested the hypothesis that mild induced hypothermia reduces coagulation and platelet aggregation in patients with septic shock. Secondary analysis of randomized controlled trial. Adult patients with septic shock who required mechanical ventilation from eight intensive care units in Denmark were randomly assigned to mild induced hypothermia for 24 h or routine thermal management. Viscoelastography and platelet aggregation were assessed at trial inclusion, after 12 h of thermal management, and 24 h after inclusion. A total of 326 patients were randomized to mild induced hypothermia (n = 163) or routine thermal management (n = 163). Mild induced hypothermia slightly prolonged activated partial thromboplastin time and thrombus initiation time (R time 8.0 min [interquartile range, IQR 6.6–11.1] vs. 7.2 min [IQR 5.8–9.2]; p = .004) and marginally inhibited thrombus propagation (angle 68° [IQR 59–73] vs. 71° [IQR 63–75]; p = .014). The effect was also present after 24 h. Clot strength remained unaffected (MA 71 mm [IQR 66–76] with mild induced hypothermia vs. 72 mm (65–77) with routine thermal management, p = .9). The proportion of patients with hyperfibrinolysis was not affected (0.7% vs. 3.3%; p = .19), but the proportion of patients with no fibrinolysis was high in the mild hypothermia group (8.8% vs. 40.4%; p < .001). The mild induced hypothermia group had lower platelet aggregation: ASPI 85U (IQR 50–113) versus 109U (IQR 74–148, p < .001), ADP 61U (IQR 40–83) versus 79 U (IQR 54–101, p < .001), TRAP 108 (IQR 83–154) versus 119 (IQR 94–146, p = .042) and COL 50U (IQR 34–66) versus 67U (IQR 46–92, p < .001). In patients with septic shock, mild induced hypothermia slightly impaired clot initiation, but did not change clot strength. Platelet aggregation was slightly impaired. The effect of mild induced hypothermia on viscoelastography and platelet aggregation was however not in a range that would have clinical implications. We did observe a substantial reduction in fibrinolysis.     

Temperature management during off-pump coronary artery bypass graft surgery: a randomized clinical trial on the efficacy of a circulating water system versus a forced-air system

OBJECTIVE: The aim of this study was to evaluate the performance of a new temperature management system specifically designed for cardiac surgery (Allon ThermoWrapping Thermoregulation System; MTRE Advanced Technologies Ltd, Or Akiva, Israel) using a circulating-water garment and to compare it with a conventional forced-air cover system in order to determine whether it could reduce the incidence of perioperative hypothermia during off-pump coronary artery bypass graft (OPCAB) surgery. DESIGN: Prospective, randomized. SETTING: University, tertiary care hospital. PARTICIPANTS: Thirty-one patients undergoing primary OPCAB surgery. INTERVENTIONS: Patients undergoing OPCAB surgery were randomized into the new thermoregulation system, Allon (study group, n = 15), and the standard forced-air system, Bair Hugger (Sterile Cardiac Access blanket Model 645; Augustine SA, Berne, Switzerland) (control group, n = 16). MEASUREMENTS AND MAIN RESULTS: Rectal temperature was recorded each 30 minutes during surgery and at intensive care unit arrival. Patients in the study group had higher temperatures than the control group at all time points, and the difference reached statistical significance after 2 hours of surgery. Moreover, fewer patients in the study group suffered perioperative hypothermia (defined as rectal temperature <36 degrees C) than the control group (2/15 patients (13.3%) in the study group v 13/16 (81.3%) in the control group [p = 0.0006]). No difference in other outcomes was noted. None of the patients died in the hospital. There were no adverse events reported. CONCLUSIONS: The circulating-water garment, Allon ThermoWrapping Thermoregulation System, maintained normothermia during OPCAB surgery better than forced-air systems, especially after the first 2 hours of surgery, and it was not associated with surgical field disturbance.     

Factors influencing thigh muscle volume change with cycling exercises in acute spinal cord injury – a secondary analysis of a randomized controlled trial

Objective: To conduct a per-protocol analysis on thigh muscle volume outcomes from the Spinal Cord Injury and Physical Activity (SCIPA) Switch-On Trial.Design: Secondary analysis from an assessor-blind randomized, controlled trial.Setting: Four acute/sub-acute hospitals in Australia and New Zealand.Participants: 24 adults (1 female) within four weeks of motor complete or incomplete spinal cord injury (SCI)Intervention: Functional electrical stimulation–assisted cycling (FESC) or passive cycling (PC) 4x/week for 12 weeks.Outcome Measures: Whole thigh and muscle group volumes calculated from manually segmented MR images.Results: 19/24 participants completed ≥ twelve weeks of the intervention. Five participants experienced hypertrophy (4 FESC; 1 PC) and eight attenuation of atrophy (<20% volume loss) (3 FESC; 5 PC) in thigh muscle volume. Six participants were non-responders, exhibiting atrophy >20% (3 FESC; 3 PC). Mean (SD) change for FESC was −2.3% (25.3%) and PC was −14.0% (12.3%). After controlling for baseline muscle volumes, a strong significant correlation was found between mean weekly exercise frequency and quadriceps and hamstring volumes (r=6.25, P=0.006), regardless of mode. Average watts was highly correlated to quadriceps volumes only (r=5.92, P=0.01), while total number of sessions was strongly correlated with hamstring volumes only (r=5.91, P=0.01).Conclusion: This per-protocol analysis of FESC and PC early after SCI reports a partial response in 42% and a beneficial response in 25% of patients who completed 12 weeks intervention, regardless of mode. Strong correlations show a dose–response according to exercise frequency. Characteristics of non-responders are discussed to inform clinical decision-making.     

不同镇痛方法用于髋部或股骨干骨折患者椎管内麻醉摆放体位时镇痛效果的网状Meta分析

目的 采用网状Meta分析系统评价不同镇痛方法用于髋部或股骨干骨折患者椎管内麻醉摆放体位时的镇痛效果。
方法 计算机检索PubMed、Cochrane Library、Web of Science、EMbase、中国生物医学文献数据库(CBM)、中国知网、维普、万方，检索时间为建库至2022年8月，纳入髋部或股骨干骨折患者摆放体位和椎管内麻醉时实施镇痛的随机对照研究。由两名研究员独立进行文献筛选、资料提取和偏倚风险评价，采用Stata 17.0和RevMan 5.3软件进行统计分析。
结果 共纳入28篇文献，患者1 773例。累计排序概率曲线下面积（SUCRA）显示，降低摆放体位时VAS疼痛评分PENG阻滞（94.4%）效果最佳，其次是FIB联合IVA（83.8%）和FIB（71.1%）；降低椎管内麻醉时VAS疼痛评分PENG阻滞（98.2%）效果最佳，其次是FIB（71.1%）和FNB（55.6%）；缩短椎管内麻醉操作时间PENG阻滞（84.1%）效果最佳，其次是FNB（70.7%）和FIB（68.5%）；升高体位摆放质量评分PENG阻滞（99.1%）效果最佳，其次是FIB（73.1%）和FNB（52.9%）。
结论 神经阻滞或神经阻滞联合IVA可降低髋部或股骨干骨折患者体位摆放和椎管内麻醉时VAS疼痛评分、缩短麻醉操作时间和升高体位摆放质量评分。PENG阻滞对髋部或股骨干骨折患者摆放体位和椎管内麻醉时实施镇痛的效果最佳。     

Uterine externalization versus in situ repair of hysterotomy during cesarean delivery: a systematic review,equivalence meta-analysis,and trial sequential analysis

BackgroundUterine positioning during hysterotomy repair is controversial, with both in situ and externalized approaches commonly performed. Despite many published trials, clinical equipoise remains. This meta-analysis and trial sequential analysis (TSA) summarizes studies comparing both techniques.MethodsA systemic search for randomized controlled trials comparing in situ with externalized hysterotomy repair during cesarean delivery was performed. The primary outcomes were estimated blood loss (EBL) and surgical duration. Secondary outcomes were need for blood transfusion, incidence of endometritis, hospital length of stay, intra-operative hypotension, return of bowel function, intra-operative vomiting, intra-operative pain, and need for postoperative analgesia. Cochrane methodology was used to assess risk of bias. Data are presented as mean difference/standardized mean difference or odds ratio/risk difference with 95% confidence intervals (CI).ResultsNineteen studies enrolling 20 739 patients were included. Estimated blood loss and surgical duration were equivalent between methods, with TSA confirming adequate information size for surgical duration but not EBL. In situ repair was associated with faster return of bowel function (MD −0.76 days; 95% CI −1.36 to −0.15; P=0.01) and a reduction in need for breakthrough postoperative analgesia (OR 0.44; 95% CI 0.28 to 0.68; P <0.01).ConclusionsThis analysis revealed equivalence between methods for EBL and surgical duration. While the small reduction in EBL with externalized repair was not clinically or statistically significant, TSA analysis revealed an unmet information size, suggesting a potentially inconclusive result. In situ repair may be associated with less breakthrough postoperative analgesia requirement and faster return of bowel function.     

The effect of two groups of intrathecal fentanyl doses on analgesic outcomes and adverse effects in parturients undergoing cesarean delivery: a systematic review and meta-analysis of randomized controlled trials with trial sequential analysis

BackgroundVariable doses of intrathecal fentanyl (ITF) have been used for peri-operative analgesia during cesarean delivery (CD). We conducted a systematic review and meta-analysis to compare lower doses (LD; ≤12.5 µg) and higher doses (HD; >12.5 µg) of ITF in parturients undergoing CD.MethodsDatabases were searched from inception to December 2020 for randomized controlled trials (RCTs) administering ITF as an additive to local anesthetic. The primary outcome was the use of intra-operative analgesic supplementation. Time to first rescue analgesia, the incidence of peri-operative side effects and neonatal outcomes were secondary outcomes. Additional analysis was performed after stratifying trials using ≤15 µg and >15 µg of ITF. Mean difference (MD) and risk difference (RD) with 95% confidence interval (CI) were calculated.ResultsEleven RCTs met inclusion criteria. Study groups were 601 patients (LD) and 749 patients (HD). A HD of ITF reduced the risk for supplementation by 6% (95% CI 0 to 13%; P=0.05; I²=80%) compared with LD, and increased the time to first rescue analgesia (MD 55.2 min, 95% CI 20.3 to 90.1, P=0.002; I²=100%). The risk of pruritus increased by 13% (95% CI 5 to 21%; P=0.001; I²=81%). Pooled data suggest that the incidence of nausea and vomiting, and neonatal outcomes did not significantly differ.ConclusionsIn women undergoing CD, doses of ITF >12.5 µg reduced the requirement for intra-operative analgesic supplementation and prolonged the time to first rescue analgesia compared with smaller doses, but increased pruritus. On revising the cut-off to 15 µg, no significant difference was found.