Prevention of hypotension after spinal anaesthesia for caesarean section: a systematic review and network meta-analysis of randomised controlled trials

Epidural ropivacaine versus bupivacaine for cesarean sections: a system review and meta-analysis

INTRODUCTION

It is still no consensus on the use of ropivacaine or bupivacaine in epidural anesthesia for cesarean section (CS), because their anesthetic potency and relative complications remains controversial. This system review and meta-analysis aimed to compare the efficacy of epidural ropivacaine and bupivacaine for elective CSs and investigate relative complications for parturients and neonates.

METHODS

We searched PubMed, MEDLINE, Embase, Cochrane Library, Science-Direct, and Google Scholar to June 30, 2023 for randomized controlled trials (RCTs), which compared epidural ropivacaine with bupivacaine for elective CSs. The success rate of epidural anesthesia (EA) was primary outcome. The secondary outcomes included onset times of sensory block, maternal side effects, neonatal Apgar scores and umbilical artery pH.

RESULTS

We analyzed 8 RCTs with 532 parturients. 0.75% ropivacaine is associated with a shorter onset time of sensory block than 0.5% bupivacaine (SMD = -0.43, 95% CI: -0.70 to -0.17; p = .001). 0.5% ropivacaine resulted in a reduced nausea than 0.5% bupivacaine (RR = 0.49, 95% CI: 0.28 to 0.83; p = .008). In addition, there were no significant difference between ropivacaine and bupivacaine groups in terms of success rate of epidural anesthesia, maternal side effects (hypotension, bradycardia, shivering), and neonatal Apgar scores and umbilical artery pH.

CONCLUSIONS

The findings suggest that there were no significant difference between epidural ropivacaine and bupivacaine for elective CSs in terms of the success rate (85.9% vs. 83.5), maternal side effects (hypotension, bradycardia, shivering), and neonatal Apgar scores and umbilical artery pH. But compared with 0.5% bupivacaine, epidural 0.75% ropivacaine was mildly effective for reducing onset time of sensory block and 0.5% ropivacaine reduced the incidence of maternal nausea.

Determination of ED90s of Phenylephrine and Norepinephrine Infusion for Prevention of Spinal Anesthesia-Induced Hypotension in Patients with Preeclampsia During Cesarean Delivery

Background

Vasopressors remain an important strategy for managing spinal anesthesia-induced hypotension in women with preeclampsia. The aim of this study was to investigate the ED90s and efficacy ratio of phenylephrine and norepinephrine in managing spinal anesthesia-induced hypotension in women with preeclampsia during cesarean delivery.

Methods

60 women with preeclampsia, who underwent cesarean delivery, were randomly assigned to receive either a continuous intravenous infusion of phenylephrine or norepinephrine following spinal anesthesia. The initial dosage of phenylephrine or norepinephrine for the first women was 0.5 or 0.05 μg/kg/min, respectively, and subsequent infusion dosages were adjusted based on their efficacy in preventing spinal anesthesia-induced hypotension (defined as a systolic blood pressure less than 80% of the baseline level). The incremental or decremental doses of phenylephrine or norepinephrine were set at 0.1 or 0.01 μg/kg/min. The primary outcomes were the ED90s and efficacy ratio of phenylephrine and norepinephrine infusions for preventing spinal anesthesia-induced hypotension prior to delivery.

Results

The results obtained from isotonic regression analysis revealed that the ED90 values of the phenylephrine and norepinephrine group for preventing spinal anesthesia-induced hypotension were 0.597 (95% CI: 0.582-0.628) and 0.054 (95% CI: 0.053-0.056) μg/kg/min, respectively, with an efficacy ratio of 11.1:1. The results of Probit regression analysis revealed that the ED90 values were determined to be 0.665 (95% CI: 0.576-1.226) and 0.055 (95% CI: 0.047-0.109) μg/kg/min, respectively, with an efficacy ratio of 12.1:1.

Conclusion

The administration of 0.6 μg/kg/min phenylephrine and 0.05 μg/kg/min norepinephrine has been found to effectively manage a 90% incidence of spinal anesthesia-induced hypotension in women with preeclampsia.

Left-lateral position versus phenylephrine prophylactic treatment for hypotension following combined spinal epidural anesthesia during elective cesarean section

Backgroud

Hypotension is one of the most common and dangerous complications following combined spinal epidural anesthesia during elective cesarean delivery. Many methods are used to prevent or treat the hypotension with pharmacological or non-pharmacological measures. Our aim was to assess left-lateral position and phenylephrine prophylactic treatment for the prevention or treatment of maternal hypotension.

Methods

A total of 127 pregnant women were enrolled to be analyzed. The primary outcome measure was the incidence of maternal hypotension and secondary outcome measures included maternal demographic characteristics, anesthesia-to-incision time interval, birthweight and Apgar scores.

Results

The incidence of hypotension was 65.4 % in sequential reactive treatment and only 11.3 % achieved complete anesis after left-lateral position, significantly higher than 17.4 % in left-lateral position combined phenylephrine prophylactic treatment (P < 0.001). The increasing in gestational age may decrease the hypotension risk (P < 0.001). There were no significantly differences with maternal age, gravidity, parity, BMI before pregnancy, BMI before cesarean section, anesthesia-to-incision time interval, birthweight and Apgar scores (P > 0.05). The univariate logistic regression analysis revealed a significant association between treatment and hypotension (OR 0.11, 95 % CI 0.05-0.27). After adjusting for confounding variables, the risk of hypotension was decreased in subjects with treatment (OR 0.1, 95 % CI 0.04-0.25; OR 0.15, 95 % CI 0.05-0.43; OR 0.16, 95 % CI 0.05-0.46). The results of stratified and interaction analyses of the association between treatment revealed no interactive role from maternal age, gravidity and BMI before cesarean section (P > 0.05).

Conclusions

Single use of left-lateral position had limited effective and left-lateral position combined prophylactic phenylephrine used may be much better to prevent or treat hypetension, but larger studies with more robust data are needed to confirm these findings.

Comparison of terbutaline and atosiban as tocolytic agents in intrauterine repair of myelomeningocele: a retrospective cohort study

BACKGROUND

Myelomeningocele (MMC) is a neural tube defect disease. Antenatal repair of fetal MMC is an alternative to postnatal repair. Many agents can be used as tocolytics during the in utero fetal repair such as β2-agonists and oxytocin receptor antagonists, with possible maternal and fetal repercussions. This study aims to compare maternal arterial blood gas analysis between terbutaline or atosiban, as tocolytic agents, during intrauterine MMC repair.

METHODS

Retrospective cohort study. Patients were divided into two groups depending on the main tocolytic agent used during intrauterine MMC repair: atosiban (16) or terbutaline (9). Maternal arterial blood gas samples were analyzed on three moments: post induction (baseline, before the start of tocolysis), before extubation, and two hours after the end of the surgery.

RESULTS

Twenty-five patients were included and assessed. Before extubation, the terbutaline group showed lower arterial pH (7.347 ± 0.05 vs. 7.396 ± 0.02 for atosiban, p = 0.006) and higher arterial lactate (28.33 ± 12.76 mg.dL-1 vs. 13.06 ± 6.35 mg.dL-1, for atosiban, p = 0.001) levels.

CONCLUSIONS

Patients who received terbutaline had more acidosis and higher levels of lactate, compared to those who received atosiban, during intrauterine fetal MMC repair.

CT-guided ozone-mediated lumbar-renal sympathetic denervation for resistant hypertension treatment: A pilot single-arm clinical trial

BACKGROUND

Renal sympathetic denervation (RDN) reduces blood pressure (BP).

METHODS

This single-arm open-label study enrolled patients with resistant hypertension (RH) and treat them by CT-guided ozone mediated lumbar-renal sympathetic denervation (L-RDN). The primary endpoint was to assess the changes of BP over 24-h ambulatory BP monitoring (ABPM) and to evaluate the anti-hypertensive medication burden (AHMB) at 3-month follow-up. This study was registered in Chictr.org.cn (ChiCTR2300071375).

RESULTS

17 patients (mean age 65.12 ± 10.77 years) with AHMB of 4.12 ± 1.11 were enrolled. After the procedure, 7 patients (46.7 %) matched the criteria for antihypertensive medication reduction. The AHMB decreased to 3.87 ± 0.96 for the whole objectives and from 3.87 ± 0.96 to 3.55 ± 0.78 for patients with normal baseline renal function. On top of the lessened AHMB, L-RDN further reduced morning systolic BP (SBP) by -8.6 ± 4.0 mmHg (p = 0.034) and diastolic BP (DBP) by -4.6 ± 2.1 mmHg (p = 0.032) for all participants and morning SBP by -13.2 ± 3.6 mmHg (p < 0.001), morning DBP by -6.2 ± 2.4 mmHg (p = 0.011) and daytime SBP by -4.1 ± 1.6 mmHg (p = 0.009) for those with normal baseline renal function at 3-month of follow-up. No adverse events were reported intra- and post operation.

CONCLUSIONS

CT-guided ozone-mediated L-RDN might be an innovative approach of RDN for treating RH. Confirmatory studies are warranted.

Hypotension prediction index for the prevention of hypotension during surgery and critical care: A narrative review

Surgeons and anesthesia clinicians commonly face a hemodynamic disturbance known as intraoperative hypotension (IOH), which has been linked to more severe postoperative outcomes and increases mortality rates. Increased occurrence of IOH has been positively associated with mortality and incidence of myocardial infarction, stroke, and organ dysfunction hypertension. Hence, early detection and recognition of IOH is meaningful for perioperative management. Currently, when hypotension occurs, clinicians use vasopressor or fluid therapy to intervene as IOH develops but interventions should be taken before hypotension occurs; therefore, the Hypotension Prediction Index (HPI) method can be used to help clinicians further react to the IOH process. This literature review evaluates the HPI method, which can reliably predict hypotension several minutes before a hypotensive event and is beneficial for patients' outcomes.

International pharmacy survey of peripheral vasopressor infusions in critical care (INFUSE)

PURPOSE

The primary objective was to determine the proportion of hospitals that administered norepinephrine peripheral vasopressor infusions (PVIs) in critically ill adult patients. Secondary objectives were to describe how norepinephrine is used such as the maximum duration, infusion rate and concentration, and to determine the most common first-line PVI used by country.

MATERIALS AND METHODS

An international multi-centre cross-sectional survey study was conducted in adult intensive care units in Australia, US, UK, Canada, and Saudi Arabia.

RESULTS

Critical care pharmacists from 132 institutions responded to the survey. Norepinephrine PVIs were utilised in 86% of institutions (n = 113/132). The median maximum duration of norepinephrine PVIs was 24 h (IQR 24-24) (n = 57/113). The most common maximum norepinephrine PVI rate was between 11 and 20 μg/min (n = 16/113). The most common maximum norepinephrine PVI concentration was 16 μg/mL (n = 60/113). Half of the institutions had a preference to administer another PVI over norepinephrine as a first-line agent (n = 66/132). The most common alternative PVI used by country was: US (phenylephrine 41%, n = 37/90), Canada (dopamine 31%, n = 5/16), UK (metaraminol 82%, n = 9/11), and Australia (metaraminol 89%, n = 8/9).

CONCLUSIONS

There is variability in clinical practice regarding PVI administration in critically ill adult patients dependent on drug availability and local institutional recommendations.

Non-Invasive Monitoring during Caesarean Delivery: Prevalence of Hypotension and Impact on the Newborn

BACKGROUND

The aim of our study was to investigate the prevalence of perioperative hypotension after spinal anesthesia for cesarean section using non-invasive continuous hemodynamic monitoring and its correlation with neonatal well-being.

METHODS

We included 145 patients. Spinal anesthesia was performed with a combination of hyperbaric bupivacaine 0.5% (according to a weight/height scheme) and fentanyl 20 μg. Hypotension was defined as a mean arterial pressure (MAP) < 65 mmHg or <60 mmHg. We also evaluated the impact of hypotension on neonatal well-being.

RESULTS

Perioperative maternal hypotension occurred in 54.5% of cases considering a MAP < 65 mmHg and in 42.1% with the more conservative cut-off (<60 mmHg). Severe neonatal acidosis occurred in 1.4% of neonates, while an Apgar score ≥ 9 was observed in 95.9% at 1 min and 100% at 5 min.

CONCLUSIONS

Continuous non-invasive hemodynamic monitoring allowed an early detection of maternal hypotension leading to a prompt treatment with satisfactory results considering neonatal well-being.

Prophylactic intravenous norepinephrine for the prevention of hypotension during spinal anesthesia for elective cesarean section: a systematic review and dose-response meta-analysis of randomized controlled trials

Introduction: In this study, we aimed to evaluate the potential dose-response relationship between prophylactic norepinephrine (NE) infusion rates and the risks of hypotension during cesarean section following spinal anesthesia. Methods: Randomized controlled trials with two or more NE doses for post-spinal hypotension prophylaxis during cesarean section were systematically searched in the MEDLINE, Embase, Web of Science, Cochrane Central Register of Controlled Trials, and US Clinical Trials Registry databases until 31 July 2022. The primary outcome was the relative risk of maternal hypotension with different NE regimens (infusion rates or bolus doses). Secondary outcomes included the relative risks of maternal and fetal adverse events with different NE regimens. Results: Ten studies with 1,144 parturients were included for final analysis using restricted cubic splines and random-effects dose-response meta-analysis models. A significant dose-response relationship existed between NE infusion rates and the relative risks of maternal hypotension. Every 0.01 μg/kg/min increment in the NE infusion rate was associated with a 14% decrease in the incidence of post-spinal hypotension. ED50 and ED95 of NE infusion rates for post-spinal hypotension prophylaxis were estimated to be 0.046 (95% CI from 0.032 to 0.085) and 0.2 (95% CI from 0.14 to 0.37) μg/kg/min, respectively. However, a higher NE infusion rate was associated with a higher incidence of maternal hypertension. Conclusion: An increased NE infusion rate was associated with a decreased incidence of post-spinal hypotension but an increased incidence of hypertension. Therefore, 0.07 μg/kg/min was recommended as the initial NE infusion rate for clinical practice, as it was associated with the lowest risk of physician intervention for unstable hemodynamics after spinal anesthesia for cesarean delivery. Systematic Review Registration: (https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=349934), identifier (CRD42022349934).

Effect of preoperative oral rehydration before cesarean section on ultrasound assessment of gastric volume and intraoperative hemodynamic changes: a randomized controlled trial

BACKGROUND

Cesarean section often requires an urgent transfusion load due to decreased blood pressure after spinal anesthesia. This prospective randomized study aimed to investigate whether a preoperative oral rehydration solution (ORS) stabilized perioperative circulatory dynamics.

METHODS

Sixty-three parturients scheduled for cesarean section under combined spinal epidural anesthesia (CSEA) were randomly allocated to one of three groups: Group O received 500 mL ORS before bedtime and 500 mL 2 h before CSEA; Group M received mineral water instead of ORS; and Group C had no fluid intake (controls). After entering the operating room, stomach size was measured using ultrasound. Blood samples were obtained, and CSEA was induced. Vasopressors were administered when systolic blood pressure was < 90 mmHg or decreased by > 20%. As a vasopressor, phenylephrine (0.1 mg) was administered at ≥ 60 beats/min heart rate or ephedrine (5 mg) at < 60 beats/min heart rate. The primary outcome was the total number of vasopressor boluses administered. Secondary outcomes were the cross-sectional area of the stomach antrum, maternal plasma glucose levels, serum sodium levels, total intravenous fluid, bleeding volume, urine volume, operative time, and cord blood gas values after delivery.

RESULTS

The total number of vasopressor boluses was lower in Group O than in Group C (P < 0.05). Group O had lower total dose of phenylephrine than Group C (P < 0.05). There were no significant differences between Group M and other groups. No differences were detected regarding secondary outcomes.

CONCLUSIONS

In women scheduled for cesarean section, preoperative ORS stabilized perioperative circulatory dynamics. Neither ORS nor mineral water consumption increased the stomach content volume.

TRIAL REGISTRATION

This trial is registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN000019825: Date of registration 17/11/2015).

Subclavian vein ultrasound-guided fluid management to prevent post-spinal anesthetic hypotension during cesarean delivery: a randomized controlled trial

BACKGROUND

Hypotension frequently occurs after spinal anesthesia during cesarean delivery, and fluid loading is recommended for its prevention. We evaluated the efficacy of subclavian vein (SCV) ultrasound (US)-guided volume optimization in preventing hypotension after spinal anesthesia during cesarean delivery.

METHODS

This randomized controlled study included 80 consecutive full-term parturients scheduled for cesarean delivery under spinal anesthesia. The women were randomly divided into the SCVUS group, with SCVUS analysis before spinal anesthesia with SCVUS-guided volume management, and the control group without SCVUS assessment. The SCVUS group received 3 mL/kg crystalloid fluid challenges repeatedly within 3 min with a 1-min interval based on the SCV collapsibility index (SCVCI), while the control group received a fixed dose (10 mL/kg). Incidence of post-spinal anesthetic hypotension was the primary outcome. Total fluid volume, vasopressor dosage, changes in hemodynamic parameters, maternal adverse effects, and neonatal status were secondary outcomes.

RESULTS

The total fluid volume was significantly higher in the control group than in the SCVUS group (690 [650-757.5] vs. 160 [80-360] mL, p < 0.001), while the phenylephrine dose (0 [0-40] vs. 0 [0-30] µg, p = 0.276) and incidence of post-spinal anesthetic hypotension (65% vs. 60%, p = 0.950) were comparable between both the groups. The incidence of maternal adverse effects, including nausea/vomiting and bradycardia (12.5% vs. 17.5%, p = 0.531 and 7.5% vs. 5%, p = 1.00, respectively), and neonatal outcomes (Apgar scores) were comparable between the groups. SCVCI correlated with the amount of fluid administered (R = 0.885, p < 0.001).

CONCLUSIONS

SCVUS-guided volume management did not ameliorate post-spinal anesthetic hypotension but reduced the volume of the preload required before spinal anesthesia. Reducing preload volume did not increase the incidence of maternal and neonatal adverse effects nor did it increase the total vasopressor dose. Moreover, reducing preload volume could relieve the heart burden of parturients, which has high clinical significance.

CLINICAL TRIAL REGISTRATION

The trial was registered with the Chinese Clinical Trial Registry at chictr.org.cn (registration number, ChiCTR2100055050) on December 31, 2021.

Reply to Akça, B.; Bilotta, F. Time and Type of Administered Fluids during Cesarean Section Might Not Matter for Hemodynamic Outcomes, but There Are Significant Patient Safety Concerns Regarding Colloid Use in Parturients. Comment on "Theodoraki et al. Colloid Preload versus Crystalloid Co-Load in the Setting of Norepinephrine Infusion during Cesarean Section: Time and Type of Administered Fluids Do Not Matter. J. Clin. Med. 2023, 12, 1333"

We would like to take this opportunity to thank Drs Akça and Bilotta for their interest and their insightful comments [...].

A Prospective Single-Center Brazilian Study Investigating the Efficacy and Safety of Prophylactic Phenylephrine Infusion for the Management of Hypotension During Cesarean Section Under Spinal Anesthesia

Background Maternal hypotension occurs in up to 80% of parturients during cesarean section (CS) under spinal anesthesia. Phenylephrine, a direct-acting α-1 agonist, has been widely recommended for the prevention of hypotension. We evaluated the efficacy and safety of phenylephrine infusion to prevent hypotension in obese and non-obese patients during cesarean section. Methods One hundred forty-one patients were included in this single-arm study. Patients received prophylactic phenylephrine infusion at a rate of 50 μg/min-1 immediately after spinal local anesthetic injection until delivery. Hypotension was defined as a systolic blood pressure <100 mmHg or <20% of baseline. The primary outcome was the incidence of hypotension. Results The incidence of hypotension was 17%. The median and interquartile range (IQR) of the number of hypotensive episodes was 0 (0-0). It was observed that 79.1% of the patients had hypotension in the first six minutes. Reactive hypertension and bradycardia occurred in 20.5 and 12.7% of the patients, respectively. In addition, there was a higher incidence of bradycardia in pregnant women with a body index mass of < 30 kg/m-2. Patients with baseline systolic blood pressure <120 mmHg had a threefold increased risk of hypotension. The incidence of nausea and vomiting was 13.4 and 2.8%, respectively. The incidence of an Apgar score <7 at the first minute was 2.8%, and no neonates presented an Apgar score <7 at the fifth minute. A pH of <7.2 occurred in 6.3% of the neonates. All neonates had no sequelae and were discharged together with their mothers. Conclusion The prophylactic infusion of phenylephrine 50 μg/min-1 is safe and demonstrates efficacy in reducing maternal hypotension providing adequate maternal hemodynamic stability during CS under spinal anesthesia.

Comparison of metaraminol versus no metaraminol on time to resolution of shock in critically ill patients

OBJECTIVE

There is limited evidence to support metaraminol use in critically ill patients. Metaraminol is not included as a vasopressor choice in international guidelines for the management of shock. Nevertheless, metaraminol is used in rates up to 42% in this patient population. The objective of this study was to investigate the effectiveness of metaraminol for the treatment of critically ill patients with shock.

METHODS

A single-centre retrospective matched observational study was conducted in a 54-bed intensive care unit of a tertiary hospital. Patients aged 16 years or older who were admitted from 2017 to 2019 with shock were included. Patients treated with metaraminol and norepinephrine (MET-NOR) were compared with those treated with norepinephrine without metaraminol (NOR). The primary outcome was the time to resolution of shock defined as the time to cessation of vasopressors. The secondary outcome was vasopressor-free days until 28 days.

RESULTS

There were 286 patients included in this study, including 143 patients in each group. The median time to resolution of shock was 44 hours (IQR 28-66 hours) in the MET-NOR group compared with 27 hours (IQR 14-63 hours) in the NOR group (95% CI of median difference 7 to 19 hours; p<0.01). The Cox regression analysis for the time to resolution of shock showed no significant difference between groups (HR 1.24, 95% CI 0.96 to 1.60; p=0.10). However, the proportional hazards assumption was not met (p<0.01). The median number of vasopressor-free days until 28 days was 26 days (IQR 24-27 days) in the MET-NOR group compared with 27 days (IQR 25-27 days) in the NOR group (95% CI of median difference -0.8 to -0.1 day; p<0.01).

CONCLUSION

In critically ill patients, metaraminol may be associated with a longer time to resolution of shock compared with those who do not receive metaraminol.

Cost-effectiveness of mechanical thromboprophylaxis for cesarean deliveries in Brazil

OBJECTIVE

To evaluate the cost-effectiveness of using mechanical thromboprophylaxis for patients undergoing a cesarean delivery in Brazil.

METHODS

A decision-analytic model built in TreeAge software was used to compare the cost and effectiveness of intermittent pneumatic compression to prophylaxis with low-molecular-weight heparin or no prophylaxis from the perspective of the hospital. Related adverse events were venous thromboembolism, minor bleeding, and major bleeding. Model data were sourced from peer-reviewed studies through a structured literature search. A willingness-to-pay threshold of R$15,000 per avoided adverse event was adopted. Scenario, one-way, and probabilistic sensitivity analyses were performed to evaluate the impact of uncertainties on the results.

RESULTS

The costs of care related to venous thromboembolism prophylaxis and associated adverse events ranged from R$914 for no prophylaxis to R$1,301 for low-molecular-weight heparin. With an incremental cost-effectiveness ratio of R$7,843 per adverse event avoided. Intermittent pneumatic compression was cost-effective compared to no prophylaxis. With lower costs and improved effectiveness, intermittent pneumatic compression dominated low-molecular-weight heparin. The probabilistic sensitivity analyses showed that the probability of being cost-effective was comparable for intermittent pneumatic compression and no prophylaxis, with low-molecular-weight heparin unlikely to be considered cost-effective (0.07).

CONCLUSIONS

Intermittent pneumatic compression could be a cost-effective option and is likely to be more appropriate than low-molecular-weight heparin when used for venous thromboembolism prophylaxis for cesarean delivery in Brazil. Use of thromboprophylaxis should be a risk-stratified, individualized approach.

The anesthetic approach to a patient with placenta accreta spectrum

PURPOSE OF REVIEW

Placenta accreta poses significant risk of morbidity and mortality to a laboring patient. Here we review available treatment options, highlight trends in bleeding prevention and diagnosis that have been shown to improve patient outcome, and provide best practice suggestions. We also discuss the decision-making process for choice of anesthesia, as it is not based on a gold-standard paradigm.

RECENT FINDINGS

The use of resuscitative endovascular balloon occlusion of the aorta has been gaining popularity around the world. It has been shown to cause an equivocal reduction in perioperative bleeding in placenta accreta spectrum (PAS), reduce the rate of hysterectomies, and is a safe and relatively easy technique. There are other invasive radiology techniques that have also proven to be beneficial in bleeding prevention: balloon occlusion of hypogastric arteries intraoperatively, internal iliac artery embolization, and intraoperative ligation of the hypogastric or uterine arteries.

SUMMARY

Optimal management of PAS begins with early and definitive diagnosis. A multidisciplinary approach along with preparation of special equipment and the use of a check-list maximize the chance for success. Anesthesia could be done with all types of regional or under general, considering case-by-case factors but most importantly choosing according to the institution's best facility and skill.

Prophylactic Norepinephrine and Phenylephrine Boluses to Prevent Postspinal Anesthesia Hypotension During Cesarean Section: A Randomized Sequential Allocation Dose-Finding Study

Background

Norepinephrine and phenylephrine are widely used for obstetric anesthesia. Our central objective was to determine the ED (effective dose) 90 and potency ratio of prophylactic norepinephrine and phenylephrine boluses for preventing postspinal anesthesia hypotension during cesarean section.

Methods

Patients scheduled for elective cesarean section (n = 80) were randomly allocated to receive prophylactic norepinephrine (NE) or phenylephrine (PE) boluses immediately after induction of spinal anesthesia. An initial dose of NE (3 μg) and PE (37.5 μg) was given to the first patient, and an up-and-down sequential allocation method was used to determine the next dose level according to the responses (the effectiveness for preventing postspinal anesthesia hypotension [defined as SBP < 80% of baseline value]). Primary outcomes were ED90 and the potency ratio of prophylactic norepinephrine and phenylephrine boluses. Secondary outcomes were the incidence of postspinal anesthesia hypotension, severe postspinal anesthesia hypotension, nausea, vomiting, bradycardia, hypertension, umbilical artery blood gas values, and Apgar scores.

Results

The ED90 values for prophylactic norepinephrine and phenylephrine boluses were 8.0 μg (95% CI 7.1-11.0 μg) and 90.9 μg (95% CI 82.0-123.9 μg), respectively. The estimated relative potency ratio was 11.4:1. The incidence of bradycardia was lower in the NE group (2.5% vs 20%, P = 0.034). Other outcomes were comparable between the two groups.

Conclusion

An 8-μg prophylactic bolus of norepinephrine and a 90-μg prophylactic bolus of phenylephrine can effectively prevent postspinal anesthesia hypotension in patients during cesarean section.

Colloid Preload versus Crystalloid Co-Load in the Setting of Norepinephrine Infusion during Cesarean Section: Time and Type of Administered Fluids Do Not Matter

Background and Goal of Study: Spinal anesthesia for cesarean section is frequently associated with a high incidence of hypotension, which may bring about untoward effects for both the mother and fetus. Recently, norepinephrine has emerged as a promising alternative in maintaining blood pressure in the obstetric setting. Fluid administration is another technique still widely used to prevent maternal hypotension. The optimal fluid strategy to prevent maternal hypotension has not been elucidated yet. It has been recently suggested that the main strategy in the prevention and management of hypotension should be the combination of vasoconstrictive medications and fluid administration. The aim of this randomized study was to compare the incidence of maternal hypotension in parturients receiving either colloid preload or crystalloid co-load in the setting of prophylactic norepinephrine infusion during elective cesarean section under combined spinal-epidural anesthesia. Materials and Methods: After ethics committee approval, 102 parturients with full-term singleton pregnancies were randomly allocated to either 6% hydroxyethyl starch 130/0.4 5 mL/kg before the onset of spinal anesthesia (colloid preload group) or Ringer's lactate solution 10 mL/kg concurrent with the subarachnoid injection (crystalloid co-load group). In both groups, norepinephrine 4 μg/min starting simultaneously with the administration of the subarachnoid solution was also administered. The primary outcome of the study was the incidence of maternal hypotension, defined as systolic arterial pressure (SAP) <80% of baseline. The incidence of severe hypotension (SAP < 80 mmHg), total dose of vasoconstrictive agents administered, as well as the acid-base status and Apgar score of the neonate and any incidence of maternal side effects were also recorded. Results: Data analysis was performed on 100 parturients: 51 in the colloid preload group and 49 in the crystalloid co-load group. No significant differences were demonstrated between the colloid preload group and the crystalloid co-load group in the incidence of hypotension (13.7% vs. 16.3%, p = 0.933) or the incidence of severe hypotension (0% vs. 4%, p = 0.238). The median (range) ephedrine dose was 0 (0-15) mg in the colloid preload group and 0 (0-10) mg in the crystalloid co-load group (p = 0.807). The incidence of bradycardia, reactive hypertension, requirement for modification of vasopressor infusion, time to the first occurrence of hypotension, and maternal hemodynamics did not differ between the two groups. There were no significant differences in other maternal side effects or neonatal outcomes between groups. Conclusions: The incidence of hypotension with a norepinephrine preventive infusion is low and comparable with both colloid preload and crystalloid co-load. Both fluid-loading techniques are appropriate in women undergoing cesarean delivery. It appears that the optimal regimen for prevention of maternal hypotension is a combined strategy of a prophylactic vasopressor such as norepinephrine and fluids.

Evaluating an advanced double intravenous vasopressor automated system to treat hypotension during spinal anesthesia for cesarean delivery: a randomized controlled trial

BACKGROUND

The optimal treatment of hypotension during spinal anaesthesia is uncertain. A novel double intravenous vasopressor automated (DIVA) system reduces hypotension compared to standard care, and was subsequently modified to an advanced-DIVA (ADIVA) system. The primary objective was to compare ADIVA versus DIVA on incidence of hypotension (systolic BP (SBP) < 80% baseline).

METHODS

We conducted a randomized-controlled trial in women undergoing elective cesarean delivery under spinal anesthesia. SBP and heart rate were measured continuously using a Nexfin monitor. ADIVA delivered 25 μg phenylephrine (heart rate > 60 beats.min^-1) or 2 mg ephedrine (heart rate < 60 beats.min^-1) at SBP 90 to 110% of baseline, 50 μg phenylephrine or 4 mg ephedrine at SBP 80 to 90%, and 75 μg phenylephrine or 6 mg ephedrine at SBP < 80%. ADIVA calculated the trend of SBP; vasopressors were administered rapidly if SBP trended downward, or 30 s if SBP trended upward. In contrast, DIVA delivered 25 μg phenylephrine or 2 mg ephedrine at SBP 90 to 100% of baseline, and 50 μg phenylephrine or 4 mg ephedrine at SBP < 90%. Boluses were followed by a 10-s lockout. Other outcomes included hypertension (SBP > 120% baseline), vasopressor consumption, clinical outcomes, and performance measures from spinal anesthesia to fetal delivery.

RESULTS

We analyzed 94 parturients (ADIVA: n = 46, DIVA: n = 48), with no difference in the incidence of hypotension between ADIVA (78.3%) and DIVA (83.3%, p = 0.677). ADIVA had significantly higher proportion of hypotensive SBP readings, lower phenylephrine consumption and higher umbilical arterial pH. There was no difference in hypertension, bradycardia, ephedrine consumption, intravenous fluid volume, nausea/vomiting, Apgar scores, and umbilical venous pH or lactate. ADIVA maintained SBP higher above baseline with greater fluctuation than DIVA.

CONCLUSION

ADIVA was associated with a greater proportion of hypotensive SBP readings, reduced phenylephrine consumption, and increased umbilical arterial pH than DIVA. Further research is needed to determine the optimal method of vasopressor delivery in parturients undergoing cesarean delivery.

TRIAL REGISTRATION

This study was registered on Clinicaltrials.gov registry (NCT03620942) on 08/08/2018.

Preventing Spinal Hypotension During Cesarean Birth With Two Initial Boluses of Norepinephrine in Chinese Parturients: A Randomized, Double-Blind, Controlled Trial

BACKGROUND

Norepinephrine is effective in preventing spinal hypotension during cesarean birth; however, an optimal regimen has not been determined. We hypothesized that an initial bolus of norepinephrine improves efficacy of spinal hypotension prophylaxis beyond continuous norepinephrine alone.

METHODS

In this double-blind, controlled study, 120 patients scheduled for cesarean birth under spinal anesthesia were randomly allocated to receive a norepinephrine bolus at 0.05 or 0.10 μg/kg, followed by norepinephrine infusion at a rate of 0.05 μg·kg -1 ·min -1 . The primary outcome was the frequency of spinal hypotension during cesarean birth. The doses of the rescue drug (phenylephrine), frequency of nausea or vomiting, duration of hypotension, frequency of intraoperative hypertension, frequency of bradycardia, and fetal outcomes were also compared.

RESULTS

One-hundred-fifteen patients were included in the analysis. Compared with the 0.05 μg/kg group, the frequency of spinal hypotension was lower in the 0.10 μg/kg group (20.7% vs 45.6%; odds ratio [OR], 0.31; 95% confidence interval (CI), 0.14-0.71; P = .004). Fewer rescue doses of phenylephrine (0 [0,0] vs 0 [0,80]; 95% CI for the difference, 0 (0-0); P = .006) were required, and the frequency of nausea or vomiting was lower (5.2% vs 17.5%; OR, 0.26; 95% CI, 0.07-0.99; P = .04) in the 0.10 μg/kg group. The duration of hypotension was shorter in the 0.10 μg/kg group than that in the 0.05 μg/kg group (0 [0,0] vs 0 [0,2]; 95% CI for the difference, 0 [0-0]; P = .006). The incidence of intraoperative hypertension, frequency of bradycardia, and fetal outcomes were comparable between the 2 groups.

CONCLUSIONS

With a fixed-rate norepinephrine infusion of 0.05 μg·kg -1 ·min -1 , the 0.10 μg/kg initial bolus was more effective in reducing the incidence of spinal hypotension compared with the 0.05 μg/kg initial bolus.

Consensus on the Southeast Asian management of hypotension using vasopressors and adjunct modalities during cesarean section under spinal anesthesia

BACKGROUND AND AIMS

This consensus statement presents a comprehensive and evidence-based set of guidelines that modify the general European or US guidelines for hypotension management with vasopressors during cesarean delivery. It is tailored to the Southeast Asian context in terms of local human and medical resources, health system capacity, and local values and preferences.

METHODS AND RESULTS

These guidelines were prepared using a methodological approach. Two principal sources were used to obtain the evidence: scientific evidence and opinion-based evidence. A team of five anesthesia experts from Vietnam, the Philippines, and Thailand came together to define relevant clinical questions; search for literature-based evidence using the MEDLINE, Scopus, Google Scholar, and Cochrane libraries; evaluate existing guidelines; and contextualize recommendations for the Southeast Asian region. Furthermore, a survey was developed and distributed among 183 practitioners in the captioned countries to gather representative opinions of the medical community and identify best practices for the management of hypotension with vasopressors during cesarean section under spinal anesthesia.

CONCLUSIONS

This consensus statement advocates proactive management of maternal hypotension during cesarean section after spinal anesthesia, which can be detrimental for both the mother and fetus, supports the choice of phenylephrine as a first-line vasopressor and offers a perspective on the use of prefilled syringes in the Southeast Asian region, where factors such as healthcare features, availability, patient safety, and cost should be considered.

Ondansetron Reduces the Incidence of Hypotension after Spinal Anaesthesia: A Systematic Review and Meta-Analysis

Hypotension induced by spinal anaesthesia is a common clinical complication associated with multiple perioperative adverse events. We conducted a systemic review and meta-analysis to confirm whether ondansetron could alleviate hypotension following spinal anaesthesia. PubMed, Embase, Web of Science, and Cochrane Library were searched to identify eligible randomised controlled trials from their respective database inception dates to 30 September 2022. The primary outcome of the meta-analysis was the incidence of hypotension after spinal anaesthesia. The risk of bias in the included studies was evaluated using the revised Cochrane risk of bias tool for randomised trials (RoB 2.0). Grading of Recommendations, Assessment, Development, and Evaluation was applied to assess the level of certainty. A total of 25 studies were included in this research. The meta-analysis revealed that ondansetron significantly decreased the incidence of hypotension (RR = 0.65, 95% CI 0.53−0.80, p < 0.01, I2 = 64%) and bradycardia. In addition, patients treated with ondansetron had a reduced need for vasopressors administration. This study suggests that ondansetron may be recommended as a prophylaxis for hypotension and bradycardia following spinal anaesthesia; the level of evidence was moderate with a high level of heterogeneity.

Comparative efficacy and safety of prophylactic norepinephrine and phenylephrine in spinal anesthesia for cesarean section: A systematic review and meta-analysis with trial sequential analysis

Background: Phenylephrine is the first-line drug used to maintain blood pressure in cesarean delivery. However, it poses a high risk of bradycardia and depression of cardiac activity in pregnant women. Consequently, norepinephrine has gained popularity over the recent years, as an alternative to Phenylephrine because it is thought that prophylactic use of vasopressors may reduce the incidence of hypotension after spinal anesthesia. This systematic review compared the efficacy of both treatments.

Methods: We searched the following databases; CNKI, PubMed, Embase, Web of science, clinicaltrials.gov, Medline and Cochrane Library, for randomized controlled trials comparing the prophylactic efficacy of norepinephrine and phenylephrine on elective cesarean delivery under spinal anesthesia. The search period was from inception to July 2022, and the primary outcome indicator was incidence of bradycardia. Statistical analysis was conducted on Rev manager 5.4, and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was used to evaluate the quality of evidence from each main finding.

Results: A total of 12 papers were included in the analysis. The incidence of bradycardia (RR = 0.37, 95% CI: 0.28 to 0.49, p &lt; 0.00001) and reactive hypertension (RR = 0.58, 95% CI 0.40 to 0.83, p = 0.003) was significantly lower in the norepinephrine (NE) group compared with the phenylephrine (PE) category. In contrast, there were no statistical differences in the umbilical cord blood gas analysis pH values between the groups (arterial: MD = 0.00, 95% CI −0.00 to 0.01, p = 0.22, vein: MD = 0.01, 95% CI −0.00 to 0.02, p = 0.06). The incidence of hypotension, nausea, and vomiting did not differ significantly between the NE and PE groups (hypotension: 23% vs. 18%; nausea: 14% vs. 18%; vomiting: 5% vs. 7%, respectively).

Conclusion: Prophylactic use of norepinephrine is safe and effective in maintaining maternal hemodynamics without causing adverse events to either the pregnant woman or fetus.

Systematic Review Registration: website https://www.crd.york.ac.uk/prospero/, identifier CRD42022347095

Effect of glycopyrrolate on vasopressor requirements for non-elective cesarean section under spinal anesthesia: a randomized, double-blind, placebo-controlled trial

Background

The study aimed to investigate whether prophylactic use of glycopyrrolate decreases the vasopressor requirements to prevent hypotension following spinal anesthesia during non-elective cesarean section.

Method

In this double-blind randomized clinical trial, 258 patients undergoing non-elective cesarean section were randomly assigned (1:1) to receive intravenous 0.2 mg glycopyrrolate or normal saline (placebo) before spinal anesthesia. The primary outcome was phenylephrine equivalent needed intraoperatively. Secondary outcomes included incidences of maternal hypotension, reactive hypertension, bradycardia, need for atropine, tachycardia, intraoperative nausea/vomiting, shivering, pruritus, dry mouth, dizziness; neonatal APGAR score at 1 min and 5 min, neonatal resuscitation needed, NICU admission and neonatal death.

Results

Three patients withdrew from the study due to failed spinal anesthesia. 128 patients in the glycopyrrolate group and 127 patients in the placebo group were analyzed. The mean phenylephrine equivalent needed was 1108.96 μg in the glycopyrrolate group and 1103.64 μg in the placebo group (mean difference, 5.32 μg [95% CI − 67.97 to 78.62]; P = 0.88). Hypotension occurred in 38 patients (30%) in the glycopyrrolate group as compared with 49 patients (39%) in the placebo group (P = 0.13). Tachycardia was reported in 70% of the participants in the glycopyrrolate group and 57% of those in the placebo group (P = 0.04). No statistically significant difference was noted in hypotensive episodes > 1, reactive hypertension, bradycardia, need for atropine, nausea, vomiting, shivering, and dry mouth between the two groups. Neonatal outcomes were similar in the two groups.

Conclusion

Prophylactic use of glycopyrrolate does not decrease the requirements of vasopressor to prevent hypotension in non-elective cesarean section under spinal anesthesia.

Trial registration

Registration number: NCT04401345. Date of registration: 26/05/2020. Website: https://clinicaltrials.gov

Comparison between 10 and 12 mg doses of intrathecal hyperbaric (0.5%) bupivacaine on sensory block level after first spinal failure in cesarean section: A double-blind, randomized clinical trial

Background

Reducing adverse effects during cesarean delivery and improving the quality of sensory blocks with appropriate doses of intrathecal hyperbaric bupivacaine can play an important role in the safe management of cesarean delivery. The aim of this study was to compare the doses of 10 and 12 mg of intrathecal hyperbaric bupivacaine 0.5% on sensory block level after first spinal failure in cesarean section (CS).

Methods

In this double-blind, randomized clinical trial, 40 candidates of CS after first spinal failure with class I-II based on American Society of Anesthesiologists (ASA) were randomly assigned into two equal groups (n = 20). Group A and B received the spinal anesthesia with 10 mg and 12 mg of hyperbaric bupivacaine (0.5%), respectively. Maximum levels of sensory block, motor block quality, and vital signs were measured in two groups by 60 min after SPA. Incidence of SPA complications during surgery were also recorded. Data were analyzed by SPSS ver.21 software using repeated measures analysis of variance at 95% confidence interval (CI) level.

Results

Excellent quality of sensory blocks and complete quality of motor blocks were achieved in all participants (100%). However, the mean time to onset of anesthesia (4.47 ± 0.69 vs. 3.38 ± 0.47, P < 0.001) and time to reach T10 level (60.73 ± 11.92 vs. 79.00 ± 19.21, P < 0.001) in the Group A, were significantly shorter than in the patients of Group B. The incidence of hypotension (P = 0.001), nausea/vomiting (P = 0.007) and bradycardia (P = 0.012) as well as administration of ephedrine and atropine were significantly higher in Group B compared to Group A.

Conclusion

Spinal anesthesia can be safely repeated with a 10 mg of hyperbaric bupivacaine 0.5% in a caesarean section after the initial spinal failure.

Clinical trial registration

[https://en.irct.ir/trial/40714], identifier [IRCT20120915010841N20].

Effectiveness of Prophylactic Bolus Ephedrine Versus Norepinephrine for Management of Postspinal Hypotension during Elective Caesarean Section in Resource Limited Setting: A Prospective Cohort Study

Background. Spinal anaesthesia for caesarean section is the preferred technique since it provides better maternal safety and neonatal outcome compared to general anaesthesia. Hypotension is the most common complication after spinal anaesthesia. The study aims to determine the effectiveness of a prophylactic bolus dose of norepinephrine and ephedrine on the management of postspinal hypotension during caesarean section. Method. An institutional-based prospective cohort study was conducted on 84 pregnant women undergoing elective caesarean section. Based on the responsible anaesthetist’s postspinal hypotension management plan, patients were divided into two groups. Those patients who received ephedrine are grouped into the ephedrine (EPH, n = 42) group, and patients who received norepinephrine are grouped under the norepinephrine group (NE, n = 42) by data collectors. After aseptic technique, spinal anaesthesia was administered with 0.5% (3 ml) bupivacaine using a 23G spinal needle. During spinal anaesthesia, a prophylactic bolus dose of 10 mg (2 ml) EPH or 16 g (2 ml) NE was given based on management plan of the shift anaesthetist. Mean arterial pressure (MAP), the heart rate (HR), number of boluses of vasopressor used, incidence of nausea and vomiting, and the Apgar score of babies at 1 and 5 min between the groups were recorded. Results. The norepinephrine group had a statistically significant higher MAP compared to the ephedrine group in the first 10 and 15 min ( $p<0.05$ ) of the study period. Thereafter, there was no statistically significant difference in MAP between the groups until the end of the study period ( $p>0.05$ ). The ephedrine group had a statistically significant higher heart rate throughout the procedure compared to the norepinephrine group ( $p<0.05$ ). The norepinephrine group required a lower bolus number of vasopressors compared to the ephedrine group to maintain blood pressure. The Apgar scores of all babies at 1 and 5 min were above seven. Significant differences regarding maternal complications (nausea and vomiting) between the groups were not detected (nausea, $p=0.21$ and vomiting, $p=0.092$ ). Conclusion. Norepinephrine can be used instead of ephedrine to keep a pregnant mother’s blood pressure stable during a caesarean section under spinal anaesthesia without causing harm to the mother or baby. Trial registration. ClinicalTrials.gov Identifier: NCT05522088 (Date of registration: 30/08/22).

Effect of Weight-Adjusted Phenylephrine, Norepinephrine, and Metaraminol for Elective Cesarean Delivery on Neonatal Acid–Base Status: A Randomized Controlled Trial

Purpose

Many previous trials have compared the effects of different vasoactive drugs on cesarean section patients, but their infusion rate is based on experience rather than high-quality evidence. It is difficult to judge whether the effect of vasoactive drug comes from the better choice or a more appropriate at rates of vasoactive drugs. The effect of vasoactive drugs at the rates of the 90% effective dose needs to be verified and compared.

Patients and Methods

Women undergoing elective caesarean delivery under combined spinal-epidural anaesthesia were randomized to receive phenylephrine or norepinephrine or metaraminol infusion at the rate that was assumed to be the 90% effective dose. Anesthetic management was standardized and included fluid loading with 10 mL/kg of Ringer. The primary outcome was the umbilical artery pH.

Results

78 patients were included. The umbilical artery pH was not significantly different among the three groups (phenylephrine group: 7.33 ± 0.03 vs norepinephrine group: 7.33 ± 0.04 vs metaraminol group: 7.33 ± 0.04, P = 0.99). There were no significant differences in the incidence of hypotension, hypertension, bradycardia, and nausea and vomiting among the three groups. The SBP of the phenylephrine group was significantly higher than that of the metaraminol group (adjustive P value = 0.005).

Conclusion

Phenylephrine (0.54 μg/kg/min) or metaraminol (2 μg/kg/min) or norepinephrine (0.08 μg/kg/min) administered to healthy patients with elective cesarean section after spinal anesthesia has no significant effect on the acid-base balance of the fetus.

Spinal hypotension in obstetrics: Context-sensitive prevention and management

Spinal hypotension during caesarean section remains a common complication, with important attendant maternal and fetal adverse outcomes. Research elucidating the mechanisms of spinal hypotension has led to the development and refinement of effective management strategies, with a particular emphasis on prophylactic vasopressor administration. This has proved effective in well-resourced settings, with maternal comfort and the elimination of nausea now considered the primary aim of treatment. In resource-limited settings, sophisticated strategies are not feasible due to insufficient equipment, staff, and expertise. Therefore, in these areas spinal hypotension remains an important cause of maternal and fetal morbidity and mortality. Translational, context-sensitive research in resource-limited settings has shown promise in implementing pragmatic strategies based on research from resource-rich environments. We review the current best practice for the prevention and treatment of spinal hypotension, with a special emphasis on effective strategies in resource-limited settings. We further suggest a research agenda to address the knowledge gap in specific contexts.

Appropriate Method of Administering Vasopressors for Maternal Hypotension Associated with Combined Spinal Epidural Anesthesia in Elective Cesarean Section: Impact on Postnatal Respiratory Support for Newborns

Background and Objectives: Vasopressors are used for treating maternal hypotension. However, the appropriate administration method and effects on newborns have not been reported. We evaluated maternal blood pressure fluctuation and neonatal findings in patients who received continuous vasopressor administration during elective cesarean sections and those who received bolus vasopressor administration upon onset of hypotension. Materials and Methods: We retrospectively analyzed the data of 220 patients scheduled for elective cesarean delivery under spinal anesthesia at Mie University Hospital between April 2017 and March 2021. The patients were classified according to the method of vasopressor administration. Maternal information, intraoperative maternal blood pressure fluctuation, and neonatal findings were examined. A multiple regression analysis was performed for the administration of postpartum neonatal respiratory support using maternal background information and other variables related to blood pressure changes as independent variables. Results: The Continuous group and the Bolus group were composed of 98 and 122 patients, respectively. No difference was observed in maternal background information between the groups. Significant changes were noted in several blood pressure parameters between both groups. As for neonatal parameters, newborns of Bolus group patients had lower pO2, 1 min and 5 min Apgar scores, and required more respiratory support than those of Continuous group patients. In the multiple regression analysis, the groups and maternal post-anesthesia diastolic blood pressure variability were considered explanatory variables. Conclusions: Maternal hypotension and the need for neonatal respiratory support associated with anesthesia administration in elective cesarean section may be improved by continuous vasopressor administration upon induction of combined spinal–epidural anesthesia.

Anesthetic management of cesarean section in a patient with Takayasu's arteritis: a case report

BACKGROUND

Takayasu's arteritis (TA) is a chronic, progressive, inflammatory arteritis. We presented the case of cesarean section in a patient with TA.

CASE PRESENTATION

A 31-year-old pregnant woman with TA underwent a planned cesarean section at 34 weeks of pregnancy. She had stenosis of the cerebral and coronary arteries and heart failure due to aortic regurgitation. Spinal anesthesia was performed. In addition to standard monitoring, arterial blood pressure in the dorsalis pedis artery and regional cerebral tissue oxygen saturation were monitored. Intraoperative arterial blood pressure was maintained using continuous infusion of noradrenaline with a careful intermittent bolus infusion of phenylephrine. All the procedures were successfully performed without significant complications.

CONCLUSIONS

In a pregnant woman with TA, severe stenosis of the cerebral and coronary arteries, and heart failure due to valvular heart disease, careful anesthetic management by selecting catecholamines and assessing the perfusion pressure for critical organs is important.

Colloid coload versus crystalloid coload to prevent maternal hypotension in women receiving prophylactic phenylephrine infusion during caesarean delivery: a randomised controlled trial

BACKGROUND

The optimal fluid strategy to prevent maternal hypotension during caesarean delivery remains unclear. This study aim was to compare the incidence of post-spinal anaesthesia hypotension in women receiving either colloid or crystalloid coload in the setting of prophylactic phenylephrine infusion during caesarean delivery.

METHODS

Healthy mothers undergoing elective caesarean delivery under spinal anaesthesia were randomised to receive a rapid intravenous coload with 6% hydroxyethyl starch 130/0.4 10 mL/kg (colloid group) or balanced crystalloid solution (Plasma Solution A) 10 mL/kg (crystalloid group) during spinal anaesthesia. All women had a prophylactic phenylephrine infusion initiated at 25 μg/min immediately after the subarachnoid block and titrated to systolic blood pressure using a standardised protocol. The primary outcome was the incidence of hypotension (systolic blood pressure <80% of baseline) until delivery.

RESULTS

The incidence of hypotension was 50% in the colloid group and 62% in the crystalloid group (absolute difference, -12% [95% CI -33% to 9%]; relative risk, 0.8 [95% CI 0.56 to 1.14]; P=0.314). No significant difference between groups was found in the number of hypotensive episodes (median 0.5 [IQR 0 to 1] vs 1 [0 to 2], P=0.132) or phenylephrine dose (675 [IQR 425 to 975] μg vs 750 [625 to 950] μg, P=0.109). The incidence of severe hypotension, symptomatic hypotension, bradycardia, nausea, and the neonatal outcomes were not significantly different.

CONCLUSIONS

This study found no benefit of colloid coload compared with crystalloid coload for preventing maternal hypotension in the presence of prophylactic phenylephrine infusion during caesarean delivery.

Performance of the Hypotension Prediction Index With Noninvasive Arterial Pressure Waveforms in Awake Cesarean Delivery Patients Under Spinal Anesthesia

BACKGROUND

Arterial hypotension is common after spinal anesthesia (SA) for cesarean delivery (CD), and to date, there is no definitive method to predict it. The hypotension prediction index (HPI) is an algorithm that uses the arterial waveform to predict early phases of intraoperative hypotension. The aims of this study were to assess the diagnostic ability of HPI working with arterial waveforms detected by ClearSight system in predicting impending hypotension in awake patients, and the agreement of pressure values recorded by ClearSight with conventional noninvasive blood pressure (NIBP) monitoring in patients undergoing CD under SA.

METHODS

In this retrospective analysis of pregnant patients scheduled for elective CD under SA, continuous hemodynamic data measured with the ClearSight monitor until delivery were downloaded from an Edwards Lifesciences HemoSphere platform and analyzed. Receiver operating characteristic (ROC) curves were constructed to evaluate the performance of HPI algorithm working on the ClearSight pressure waveform in predicting hypotensive events, defined as mean arterial pressure (MAP) <65 mm Hg for >1 minute. The sensitivity, specificity, positive predictive value, and negative predictive value were computed at the optimal cutpoint, selected as the value that minimizes the difference between sensitivity and specificity. ClearSight MAP values were compared to NIBP MAP values by linear regression and Bland-Altman analysis corrected for repeated measurements.

RESULTS

Fifty patients undergoing CD were included in the analysis. Hypotension occurred in 23 patients (48%). Among patients experiencing hypotension, the HPI disclosed 71 alerts. The HPI predicted hypotensive events with a sensitivity of 83% (95% confidence interval [CI], 69-97) and specificity of 83% (95% CI, 70-95) at 3 minutes before the event (area under the curve [AUC] 0.913 [95% CI, 0.837-0.99]); with a sensitivity of 97% (95% CI, 92-100) and specificity of 97% (95% CI, 92-100) at 2 minutes before the event (AUC 0.995 [95% CI, 0.979-1.0]); and with a sensitivity of 100% (95% CI, 100-100) and specificity 100% (95% CI, 100-100) 1 minute before the event (AUC 1.0 [95% CI, 1.0-1.0]). A total of 2280 paired NIBP MAP and ClearSight MAP values were assessed. The mean of the differences between the ClearSight and NIBP assessed using Bland-Altman analysis (±standard deviation [SD]; 95% limits of agreement with respective 95% CI) was -0.97 mm Hg (±4.8; -10.5 [-10.8 to -10.1] to 8.5 [8.1-8.8]).

CONCLUSIONS

HPI provides an accurate real time and continuous prediction of impending intraoperative hypotension before its occurrence in awake patients under SA. We found acceptable agreement between ClearSight MAP and NIBP MAP.

Maternal heart rate responses in the supine position and their relationship with hypotension and phenylephrine requirements during elective caesarean delivery using spinal anaesthesia: An observational study

BACKGROUND

Hypotension is the main side effect of spinal anaesthesia (SA) for elective caesarean delivery (CD). An increased in heart rate in response to inferior vena cava (IVC) compression has been reported to be predictive of hypotension and vasopressor requirements in this setting. The objective of the study was to evaluate the prevalence of an increase in heart rate in response to IVC compression and its potential effect on hypotension and phenylephrine requirements.

METHODS

Healthy parturients scheduled for elective CD under SA were preoperatively investigated for a positive supine stress test (SST). It was defined as an increase in heart rate (HR) > 10 beats/min after 5 min of supine position. A crystalloid coload and prophylactic phenylephrine infusion were systematically used to maintain systolic arterial pressure (SAP) between 90-100% of baseline. Hypotension was defined as SAP < 80% of baseline.

RESULTS

Among 100 women, 26% had a positive SST. There was no significant difference in the incidence of hypotension: 38% versus 24.3% (p = 0.17) in women with positive SST or without, respectively. The cumulative dose of phenylephrine (450 µg [325-625] versus 350 µg [250-500], p = 0.09) was not significantly different between the two groups. Incidences of reactive hypertension, bradycardia, nausea or vomiting and neonatal outcomes were comparable.

CONCLUSIONS

A positive SST to IVC compression was found in a quarter of term women scheduled for elective CD under SA. This condition has no significant impact on hypotension and phenylephrine requirements when using a crystalloid coload and a phenylephrine infusion targeted at maintaining SAP close to baseline.

Blood pressure and cardiac output during caesarean delivery under spinal anaesthesia: a prospective cohort study

OBJECTIVES

We have previously established a method to measure transfer of nutrients between mother, placenta and fetus in vivo. The method includes measurements of maternal and fetal blood flow by Doppler ultrasound prior to spinal anaesthesia. Spinal anaesthesia affects maternal blood pressure and cardiac output. We aimed to determine the effect of spinal anaesthesia in mothers undergoing an elective caesarean section on blood pressure, heart rate and cardiac output, and whether cardiac output levels were comparable before induction of spinal anaesthesia and before delivery.

DESIGN

Prospective cohort study.

SETTING

Tertiary hospital in Norway.

PARTICIPANTS

76 healthy women with uneventful pregnancies undergoing an elective caesarean section.

INTERVENTIONS

We induced spinal anaesthesia with a standard prevention of hypotension including intravenous fluid coloading and phenylephrine infusion.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome measure was maternal cardiac output, and secondary outcome measures were invasive systolic blood pressure and heart rate. We measured heart rate and blood pressure by continuous invasive monitoring with a cannula in the radial artery. Cardiac output was estimated based on continuous arterial waveform. We compared maternal parameters 30 s before induction of spinal anaesthesia to 30 s before delivery.

RESULTS

Median age at delivery was 34.5 (range 21-43) years and 17 of 76 women were nulliparous. The most prevalent indications were previous caesarean section and maternal request. Among 76 included women, 71 had sufficient data for analysis of endpoints. Median cardiac output was 6.51 (IQR (5.56-7.54) L/min before spinal anaesthesia and 6.40 (5.83-7.56) L/min before delivery (p=0.40)). Median invasive systolic blood pressure increased from 128.5 (120.1-142.7) mm Hg to 134.1 (124.0-146.6) mm Hg (p=0.014), and mean heart rate decreased from 86.0 (SD 13.9) to 75.2 (14.2) (p<0.001).

CONCLUSIONS

Maternal cardiac output at the time of caesarean delivery is comparable to levels before induction of spinal anaesthesia.

TRIAL REGISTRATION NUMBER

NCT00977769.

Mephentermine Misuse: An Impending Crisis among Sportspersons

Mephentermine is a sympathomimetic amine, frequently used as a vasopressor. It is structurally comparable to amphetamines, and World Anti-Doping Agency has prohibited its use as a performance-enhancing drug. However, its illegal consumption by several sportspersons and those appearing for physical endurance tests is a growing concern for health-care professionals. We present a case of misuse of intravenous mephentermine by a young male who abruptly increased its amount a few days prior to the sports competition and developed acute psychosis. The case report highlights the need for strict regulations for procuring methamphetamine and effective treatment strategies for managing its misuse.

A Randomized Double-Blinded Dose-dependent Study of Metaraminol for Preventing Spinal-Induced Hypotension in Caesarean Delivery

Purpose: Prophylactic infusion of a vasopressor is preferred as a rational choice in clinical practice in Cesarean delivery. Metaraminol is one of most common vasopressors used in obstetric clinical practice. However, the dose-response of metaraminol has not been fully determined and the optimal infusion dose is unknown. Therefore, this study aimed to determine the median effective dose (ED50) and 90% effective dose (ED90) of weight-based fixed-rate metaraminol infusions for preventing spinal-anesthesia-induced hypotension in patients having combined spinal-epidural anesthesia for elective Caesarean delivery.

Methods: One hundred and seventeen patients with singleton pregnancies were enrolled and randomly allocated into one of five groups in this study. Patients received prophylactic metaraminol infusion at a fixed rate of 0, 0.25, 1.0, 1.75 or 2.5 μg/kg/min in each group immediately after induction with intrathecal 10 mg of hyperbaric bupivacaine mixed with 5 μg of sufentanil. An effective prophylactic dose was defined as no occurrence of hypotension during the period of spinal introduction and neonatal delivery. Values for ED50 and ED90 of prophylactic infusion of metaraminol were calculated using probit regression. Characteristics of spinal anesthesia and side effects were recorded.

Results: The ED50 and ED90 values of weight-based fixed rate of metaraminol infusion were 0.64 (95% CI, 0.04–1.00) μg/kg/min and 2.00 (95% CI, 1.58–2.95) μg/kg/min respectively. The incidence of hypotension decreased with an increased infusion rate of metaraminol in the five groups (test for trend, p < 0.001). The incidence of hypotension was similar between group 0 and 0.25, but significant higher than other groups; the incidence of hypotension was also similar between group 1.0 and 1.75, but higher than group 2.5. The incidence of reactive hypertension was significantly higher in group 2.5 compared to the other groups. Physician interventions were more frequent in group 0, 0.25 and 2.5 than in group 1.0 and 1.75 (adjusted p < 0.001). No difference was found in neonatal outcomes, including Apgar score and pH value of the umbilical artery.

Conclusion: In summary, we have compared four different prophylactic weight-based infusion doses of metaraminol for preventing post-spinal hypotension in Cesarean delivery. The ED₅₀ and ED₉₀ values of metaraminol infusion for preventing spinal anesthesia-induced hypotension were 0.64 μg/kg/min and 2.00 μg/kg/min, respectively. This finding may be helpful for guiding clinical practice and further research.

Fluid loading therapy to prevent spinal hypotension in women undergoing elective caesarean section: Network meta-analysis, trial sequential analysis and meta-regression

BACKGROUND

Fluid loading is one of the recognised measures to prevent hypotension due to spinal anaesthesia in women scheduled for a caesarean section.

OBJECTIVE

We aimed to evaluate the current evidence on fluid loading in the prevention of spinal anaesthesia-induced hypotension.

DESIGN

Systematic review and network meta-analysis with trial sequential analysis and meta-regression.

DATA SOURCES

Medline, Epub, Embase.com (Embase and Medline), Cochrane Central, Web of Science and Google Scholar were used.

ELIGIBILITY CRITERIA

Only randomised controlled trials were used. Patients included women undergoing elective caesarean section who received either crystalloid or colloid fluid therapy as a preload or coload. The comparator was a combination of either a different fluid or time of infusion.

RESULTS

A total of 49 studies (4317 patients) were included. Network meta-analysis concluded that colloid coload and preload offered the highest chance of success (97 and 67%, respectively). Conventional meta-analysis showed that crystalloid preload is associated with a significantly higher incidence of maternal hypotension than colloid preload: risk ratio 1.48 (95% CI 1.29 to 1.69, P < 0.0001, I² = 60%). However, this result was not supported by Trial Sequential Analysis. There was a significant dose–response effect for crystalloid volume preload (regression coefficient = −0.073), which was not present in the analysis of only double-blind studies. There was no dose–response effect for the other fluid regimes.

CONCLUSION

Unlike previous meta-analysies, we found a lack of data obviating an evidence-based recommendation. In most studies, vasopressors were not given prophylactically as is recommended. Studies on the best fluid regimen in combination with prophylactic vasopressors are needed. Due to official european usage restrictions on the most studied colloid (HES), we recommend crystalloid coload as the most appropriate fluid regimen.

TRIAL REGISTRATION

CRD42018099347.

Implications of Continuous Noninvasive Finger Cuff Arterial Pressure Device Use during Cesarean Delivery for Goal-Directed Fluid Therapy Preload Optimization: A Randomized Controlled Trial

Background

Although fixed-volume conventional fluid preloading protocol fails to attenuate postspinal hypotension during cesarean delivery, the effect of goal-directed fluid therapy (GDFT) remains less explored. Continuous noninvasive finger cuff arterial pressure monitoring using devices such as the ClearSight System can provide the noninvasive stroke volume value, enabling clinicians to perform GDFT before spinal anesthesia; however, the efficacy of GDFT requires further elucidation.

Method

In total, 71 consecutive full-term pregnant women were randomly divided into a control group (n = 34) and a GDFT group (n = 37). Before spinal anesthesia, the control group received a fixed dose (1000 mL) of crystalloid fluid, but the GDFT group received repeated 3 mL/kg body weight of crystalloid fluid challenges within 3 minutes with a 1-minute interval between each fluid challenge based on the stroke volume incremental changes obtained using the ClearSight System (targeting a stroke volume increase of ≥5% after a fluid challenge). The primary outcome was the incidence of postspinal hypotension. The secondary outcomes were total fluid volume, vasopressor dosage, hemodynamic parameter changes, maternal adverse effects, and neonatal profiles.

Result

Women in the GDFT group received more fluid than did those in the control group (1132 ± 108 vs. 1247 ± 202 mL; p = 0.0044), but the incidence of postspinal hypotension (79.4% vs. 73.0%,; p = 0.5864) and norepinephrine dose (12.5 ± 10.6 vs. 15.1 ± 12.8 mcg, respectively; p = 0.3512) was comparable between the two groups. Fewer women in the GDFT group experienced nausea (61.76% vs. 35.14%; p = 0.0332). Neonatal outcomes (Apgar score and umbilical blood analysis) were comparable and typical in both groups.

Conclusion

ClearSight-guided GDFT did not ameliorate postspinal hypotension but may reduce nausea. This trial is registered with NCT03013140.

Pharmacoepidemiology of metaraminol in critically ill patients with shock in a tertiary care hospital

BACKGROUND

Metaraminol is increasingly used as a vasopressor in critically ill patients. Nevertheless, there remains limited evidence to support its use in international guidelines for management of shock.

OBJECTIVES

The aim of the study was to describe the pharmacoepidemiology of metaraminol in critically ill patients with shock.

METHODS

A retrospective observational study was conducted in an intensive care unit (ICU) in Sydney, Australia. Patients admitted during a 1-year time frame who received metaraminol intravenous infusions for management of shock were included.

RESULTS

A total of 152 patients were included. When metaraminol was used, it was the most common first-line vasopressor started for management of shock (97%, n = 147) and was used as monotherapy in 53% (n = 81) of patients. The median duration of metaraminol infusion in the ICU was 7 h (interquartile range [IQR] = 3 to 19), and the median maximum metaraminol infusion rate in the ICU was 4.0 mg/h (IQR = 2.5 to 6.0). Peripheral vasopressor infusions were used in 96% (n = 146/152) of patients for a median duration of 7 h (IQR = 2 to 18). In all these cases, the peripheral vasopressor used was metaraminol (100%, n = 146/146). Patients were commonly switched from metaraminol to noradrenaline infusions after insertion of a central venous catheter (R2 = 0.89). Patients treated with metaraminol monotherapy had a lower Acute Physiology and Chronic Health Evaluation III score (58 vs 68; median difference = -9, 95% confidence interval = -16 to -3; p < 0.01) and a shorter duration of overall vasopressor use in the ICU (12 vs 39 h, median difference = -24 h, 95% confidence interval = -31 to -18; p < 0.01) than those treated with combination vasopressors. No extravasation injury was reported in the study cohort.

CONCLUSIONS

Metaraminol is often administered as a first-line peripheral vasopressor in the ICU and is used as a single agent in patients with lower severity of shock.

Comparison of two vasopressor protocols for preventing hypotension post-spinal anesthesia during cesarean section: a randomized controlled trial

Background:

Norepinephrine infusion decreases hypotension after spinal anesthesia during cesarean section. This study aimed to compare the efficacy of norepinephrine infusion and ephedrine bolus against post-spinal hypotension in parturients.

Methods:

In this double-blinded, randomized controlled clinical trial, parturients scheduled for elective cesarean section were randomly allocated to receive norepinephrine infusion (0.05 μg·kg⁻¹·min⁻¹) just before spinal anesthesia continuing for 30 min or ephedrine bolus (0.15 mg/kg) just before spinal anesthesia. A rescue bolus (5 μg norepinephrine for the norepinephrine group, and 5 mg ephedrine for the ephedrine group) was administered whenever hypotension occurred. Our primary outcome was the incidence of hypotension within 30 min of spinal anesthesia administration. Secondary outcomes included maternal and neonatal outcomes 30 min after spinal block, and neonatal cerebral oxygenation 10 min after birth.

Results:

In total, 190 patients were enrolled; of these patients, 177 were included in the final analysis. Fewer patients suffered hypotension in the norepinephrine group than in the ephedrine group (29.5% vs. 44.9%, odds ratio [OR]: 0.51, 95% confidence interval [CI]: 0.28–0.95, P = 0.034). Moreover, the tachycardia frequency was lower in the norepinephrine group than in the ephedrine group (OR: 0.22, 95% CI: 0.11–0.44, P < 0.001), and patients suffered less nausea and vomiting (OR: 0.28, 95% CI: 0.11–0.70, P = 0.004). There was no difference in Apgar scores and umbilical arterial blood gas analysis between the two groups. However, neonatal cerebral regional saturations were significantly higher after birth in the norepinephrine group than in the ephedrine group (mean difference: 2.0%, 95% CI: 0.55%–3.45%, P = 0.008).

Conclusion:

In patients undergoing elective cesarean section with spinal anesthesia, norepinephrine infusion compared to ephedrine bolus resulted in less hypotension and tachycardia, and exhibited potential neonatal benefits.

Trial Registration:

ClinicalTrials.gov, NCT02542748; https://clinicaltrials.gov/ct2/show/record/NCT02542748

The transverse diameter of right common femoral vein by ultrasound in the supine position for predicting post-spinal hypotension during cesarean delivery

Background

Post-spinal anesthesia hypotension during cesarean delivery is caused by decreased systemic vascular resistance due to the blockage of the autonomic nerves, which is further worsened by inferior vena cava (IVC) compression by the gravid uterus. This study aimed to assess whether peak velocity and diameter of the IVC below the xiphoid or right common femoral vein (RCFV) in the inguinal region, as measured on ultrasound, could reflect the degree of IVC compression and further identify parturients at risk of post-spinal hypotension.

Methods

Fifty-six parturients who underwent elective cesarean section with spinal anesthesia were included in this study; peak velocities and anteroposterior diameters of the IVC and peak velocities and transverse diameters of the RCFV were measured using ultrasound before anesthesia. The primary outcome was the ultrasound measurements of IVC and RCFV acquired before spinal anesthesia and their association with post-spinal hypotension. Hypotension was defined as a drop in systolic arterial pressure by > 20% from the baseline. Multinomial logistic regression analysis was used to identify the association between the measurements of IVC, RCFV, and post-spinal hypotension during cesarean delivery. Receiver operating characteristic curves were used to test the abilities of the identified parameters to predict post-spinal hypotension; the areas under the curve and optimum cut-off values for the predictive parameters were calculated.

Results

A longer transverse diameter of the RCFV was associated with the occurrence of post-spinal hypotension (odds ratio = 2.022, 95% confidence interval [CI] 1.261–3.243). The area under the receiver operating characteristics curve for the prediction of post-spinal hypotension was 0.759 (95% CI 0.628–0.890, P = 0.001). A transverse diameter of > 12.2 mm of the RCFV could predict post-spinal hypotension during cesarean delivery.

Conclusions

A longer transverse diameter of RCFV was associated with hypotension and could predict parturients at a major risk of hypotension before anesthesia.

Trial registration

This study was registered at http://www.chictr.org.cn on 16, May, 2018. No. ChiCTR1800016163.