Maternal hypotension during elective cesarean section and short-term neonatal outcome

Effects of neuraxial anesthesia in sitting and lateral positions on maternal hemodynamics in cesarean section: A systematic review and meta-analysis

STUDY OBJECTIVE

During cesarean section, hypotension is a frequent side effect of spinal anesthesia. As a sitting or lateral position is required for spinal anesthesia performance, which of these two positions is more likely to cause intraoperative nausea, vomiting, and hypotension is still unknown. This meta-analysis compared the effects of these two positions on maternal hemodynamics and intraoperative nausea and vomiting.

DESIGN

Systematic review and meta-analysis.

SETTING

Operating room.

PATIENTS

This study included 803 patients from 12 randomized controlled trials (RCTs).

INTERVENTIONS

Neuraxial anesthesia in sitting position vs. lateral position.

MEASUREMENTS

We chose RCTs comparing the effects of spinal anesthesia in the sitting and lateral positions on maternal hemodynamics by thoroughly searching PubMed, Embase, the Cochrane Library, and the Web of Science for articles published from database inception until October 31, 2022. The Cochrane Handbook was used to assess the methodological quality of each RCT; the results were analyzed using RevMan 5.4 software; and the Egger test was used to assess publication bias.

MAIN RESULTS

12 randomised controlled trials with 803 participants were ultimately included in the final analysis. No significant differences were observed between the two positions in terms of the incidence of hypotension(RR, 0.82; 95% CI, 0.58-1.16; P = 0.26; I2 = 66%), lowest systolic blood pressure(MD, -0.81; 95% CI, -7.38-5.75; P = 0.81; I2 = 86%), the dose of ephedrine(MD, -1.19; 95% CI, -4.91-2.52; P = 0.53; I2 = 83%), and number of parturients requiring ephedrine(RR, 0.97; 95% CI, 0.64-1.46; P = 0.88; I2 = 74%). For the incidence of intraoperative nausea and vomiting, there was no statistical difference between the two positions.

CONCLUSION

Parturients undergoing elective cesarean section under spinal anesthesia in the sitting or lateral position experienced similar incidence of hypotension, and there were no significant differences between these two positions in terms of the amount of ephedrine administered or the number of patients needing ephedrine. In both positions, the frequency of nausea and vomiting was comparable. The ideal position for anesthesia can be chosen based on the preferences and individual circumstances of the parturient and anesthesiologist.

Use of vasopressors to manage spinal anesthesia-induced hypotension during cesarean delivery

Cesarean sections are commonly performed under spinal anesthesia, which can lead to hypotension, adversely affecting maternal and fetal outcomes. Hypotension following spinal anesthesia is generally defined as a blood pressure of 80-90% below the baseline value. Various strategies have been implemented to reduce the incidence of spinal anesthesia-induced hypotension. The administration of vasopressors is a crucial method for preventing and treating hypotension. In the past decade, phenylephrine, a primarily alpha-adrenergic agonist, has been the preferred vasopressor for cesarean sections. Recently, norepinephrine, a potent alpha-agonist with modest beta-agonist activity, has gained popularity owing to its advantages over phenylephrine. Vasopressors can be administered via a bolus or continuous infusion. Although administering boluses alone is simpler in a clinical setting, continuous prophylactic infusion initiated immediately after spinal anesthesia is more effective in reducing the incidence of hypotension. Tailoring the infusion dose based on the patient's body weight and adjusting the rate in response to blood pressure changes, in addition to using a prophylactic or rescue bolus, helps reduce blood pressure variability during cesarean sections under spinal anesthesia until neonatal delivery.

Postspinal Anesthesia Hypotension in Caesarean Delivery: A Narrative Review

Anesthesiologists frequently deal with spinal hypotension when administering spinal anesthesia (SA) for a Caesarean section (C-section). The physiological changes that occur during pregnancy necessitate modifications to anesthesia and analgesia procedures to provide safe and efficient care for the expectant patient. It is believed that giving the patient SA during a C-section will increase their degree of comfort and pain management both during and after the surgical process. It is less expensive, easier to give, and delivers a consistent anesthetic onset, early ambulation, and the start of breastfeeding. As C-section is a very common operation performed in every healthcare unit, dealing with postspinal hypotension is a daily situation faced by anesthetists with variable levels of experience. However, understanding and addressing hypotension induced by SA is crucial as it affects the mother and the fetus negatively. This review aims to contribute to enhancing patient care and safety in the context of C-sections by identifying hypotension timely and managing it effectively. It is advised to healthcare workers to leverage the insights from the review to improve patient outcomes in routine practice.

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.

Effects of Hyperbaric and Isobaric Bupivacaine on Hemodynamic Profiles and Block Characteristics Among Parturients Undergoing Elective Cesarean Section Under Spinal Anesthesia: A Randomized Controlled Trial

Background

Cesarean section (CS) is a surgical procedure where the baby is delivered through incisions made in the abdomen and uterus. Bupivacaine is a widely recognized local anesthetic available in different baricity and it is frequently used for spinal anesthesia. The baricity of bupivacaine impacts hemodynamic profiles and block characteristics.

Objective

To compare the effects of hyperbaric and isobaric bupivacaine on hemodynamic profiles and block characteristics among parturients undergoing elective cesarean section under spinal anesthesia at Dilla University Referral Hospital.

Methods

64 pregnant mothers scheduled for elective cesarean section under spinal anesthesia were randomly assigned to two groups: Group A received a dose of 12.5 mg of isobaric bupivacaine (n = 32), Group B received a dose of 12.5 mg of hyperbaric bupivacaine (n = 32). Prior to conducting the study, the necessary ethical approvals were obtained. For comparing numerical variables between the two groups, the independent Sample t-test or Mann-Whitney U-test was employed as needed. Repeated measurements were analyzed using mixed ANOVA. Categorical variables were assessed using either the chi-square test or Fisher's exact test. Statistical significance was set at P < 0.05, with a power of 90%.

Results

The mean Systolic Blood Pressure (SBP), Diastolic Blood pressure (DBP), and Mean Arterial Blood Pressure (MAP) showed significant decrement in the group receiving isobaric spinal anesthesia compared to those receiving hyperbaric bupivacaine. The decrement was observed from the 6th to 30th minute (p<0.05). Furthermore, the hyperbaric group had a faster onset time for achieving the maximum sensory block, with a median time of 3 (1) min compared to 4 (2) mins in the isobaric group (p<0.001).

Conclusion and Recommendation

We conclude that hyperbaric bupivacaine provides stable intraoperative hemodynamic parameters and an earlier onset of block than isobaric bupivacaine. Therefore, we recommend clinicians to use hyperbaric bupivacaine for cesarean delivery.

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.

Incidence and Risk Factors of Spinal Anesthesia-Related Complications After an Elective Cesarean Section: A Retrospective Cohort Study

Introduction Neuraxial anesthetic techniques are the method of choice for cesarean section (CS) deliveries, and spinal anesthesia (SA) is the preferred technique. Although the use of SA has greatly improved the outcomes of CS deliveries, SA-related complications are still a matter of concern. The study's primary aim is to measure the incidence of SA complications after a CS, specifically hypotension, bradycardia, and prolonged recovery, as well as to identify the risk factors for these complications. Method The data of patients who had elective CS using SA from January 2019 to December 2020 was collected from a tertiary hospital in Jeddah, Saudi Arabia. The study design was a retrospective cohort study. The data collected included age, BMI, gestational age, comorbidities, the SA drug and dosage used, the site of the spinal puncture, and the patient's position during the spinal block. Also, the patient's blood pressure measurements, heart rate, and oxygen saturation levels were collected at baseline and at 5, 10, 15, and 20 minutes. SPSS was used for statistical analysis. Results The incidence of mild, moderate, and severe hypotension was 31.4%, 23.9%, and 30.1%, respectively. In addition, 15.1% of the patients experienced bradycardia, with 37.4% experiencing a prolonged recovery. Two factors were associated with hypotension, including BMI and the dosage of the SA, with a p-value of 0.008 and a p-value of 0.009, respectively. The site of the SA punctures equal to or lower than L2 was the only factor associated with bradycardia (p-value = 0.043). Conclusion The present study concludes that BMI and the dose of SA were the factors associated with SA-induced hypotension during a CS, and the site of the SA puncture equal to or lower than L2 was the only risk factor associated with spinal anesthesia-induced bradycardia.

Phenylephrine versus cafedrine/theodrenaline (Akrinor) for the treatment of spinal anaesthesia-induced maternal hypotension during caesarean section: a retrospective single-centre cohort study

OBJECTIVE

The main objective of this study was to assess the impact of phenylephrine and cafedrine/theodrenaline on the mother and newborn after spinal anaesthesia for caesarean section.

SETTING

University teaching hospital.

DESIGN

A single-centre retrospective data cohort study.

PATIENTS

All obstetric patients who were scheduled for caesarean section in a 2-year period.

INTERVENTIONS

Administration of either intravenous phenylephrine prophylactically or cafedrine/theodrenaline (Akrinor) reactively to maintain blood pressure after spinal anaesthesia.

MAIN OUTCOME MEASURE

Maternal hypotension, heart rate during caesarean section and after admission to IMC, fetal arterial cord pH and base excess levels, maternal volume resuscitation and the use of rescue medication.

RESULTS

852 data sets could be included: n=440 Akrinor, n=412 in the phenylephrine cohort. During caesarean section blood pressure was slightly higher in the phenylephrine group compared with the Akrinor group, while hypotension <100 mm Hg systolic blood pressure (SBP) occurred significantly more often during arrival at the IMC after surgery when phenylephrine was used. Heart rate was lower and rescue medication was significantly more frequently given in the phenylephrine cohort. Irrespective of the medication used, women with baseline levels of <120 mm Hg SBP had a high risk to develop hypotension <100 mm Hg after spinal anaesthesia for caesarean section. While there was no statistical difference in mean umbilical arterial pH levels, the incidence of acidosis, defined as pH <7.2, was significantly higher with phenylephrine.

CONCLUSION

Phenylephrine was not superior to Akrinor to treat spinal anaesthesia-induced maternal hypotension during caesarean section.

TRIAL REGISTRATION NUMBER

DRKS00025795.

Can Hypotension Episodes that were not Identified in the Non-Invasive Blood Pressure be Detected during Cesarean Section? A Randomized Controlled Trial

Background:

Aims:

Study Design:

Methods:

Results:

Conclusion:

Associated factors with umbilical arterial pH after cesarean delivery under spinal anesthesia: a retrospective cohort study

BACKGROUND

Maximum decrease of blood pressure and number of minutes of hypotension were independently associated with umbilical arterial pH. However, the impact of hypotension considering the duration of it on umbilical arterial pH is unknown.

METHODS

Pregnant women aged ≥ 20 years who delivered a baby at full-term via a cesarean delivery under a single-shot spinal anesthesia between January 2017 and March 2019 were included. The main outcome was to predict umbilical arterial pH, based on the value of the time integral of hypotension. Patient demographics, patient comorbidities, and intraoperative data, including the total dose of ephedrine and phenylephrine by fetal delivery and cumulative duration of maternal hypotension, were evaluated. Maternal hypotension was reflected as a decrease in systolic arterial pressure and mean arterial pressure to < 80% of baseline values. The systolic arterial pressure and mean arterial pressure were independently included in a multiple regression analysis along with all other explanatory factors to predict the umbilical arterial pH.

RESULTS

Of the 416 eligible patients, 381 were enrolled. When including the systolic arterial pressure or mean arterial pressure in the model, emergency cases, the total dose of ephedrine, hypertensive disorders of pregnancy, and systolic arterial pressure or mean arterial pressure values were found to be significant predictive factors of umbilical arterial pH.

CONCLUSION

Our results suggest that an elevated time integral of maternal hypotension may have a negative impact on umbilical arterial pH. Therefore, to minimize the risk of fetal acidosis, maternal hypotension should be prevented with the consideration of vasopressors selection.

Association Between Hyperbaric Bupivacaine Dose and Maternal Hypotension: Retrospective Database Study of 8226 Women Undergoing Cesarean Delivery Under Spinal Anesthesia

BACKGROUND

Low-dose (≤8 mg) hyperbaric bupivacaine for spinal anesthesia during cesarean delivery results in reduced efficacy, yet as a secondary outcome was associated with reduced frequency of spinal-induced hypotension. Our primary aim was to investigate the relationship between hyperbaric bupivacaine dose and the occurrence of spinal-induced hypotension for cesarean delivery.

METHODS

Retrospective study of cesarean delivery under spinal or combined spinal anesthesia with hyperbaric bupivacaine in 1 academic institution (2 centers-tertiary and district) from 2012 to 2018. Data were retrieved from the anesthesia information management systems (Metavision, iMDsoft, Tel Aviv, Israel) and the hospital information system, including potential confounding factors, maternal age and weight, hypertensive disease of pregnancy, single/multiple gestation, gestational age, vasopressor administration, planned/urgent surgery, position during anesthesia placement (sitting/lateral), and anesthesiologist seniority. Spinal-induced hypotension was defined as systolic blood pressure that either dropped >20% from baseline or <100 mm Hg. The primary outcome of interest was the incidence of spinal-induced hypotension according to hyperbaric bupivacaine dose. Logistic regression was used to characterize the association between the dose of hyberbaric bupivacaine and spinal-induced hypotension after adjusting for confounding factors.

RESULTS

A total of 8226 women were identified. The hyperbaric bupivacaine dose administered was <9 mg for 2395 (29.1%), 9-9.5 mg for 1031 (12.5%), 10 mg for 4155 (50.5%), and >10 mg for 645 (7.8%). We used a cutoff (<10 vs ≥10 mg) to assess for the primary outcome, using multivariable logistic regression. The incidence of at least 1 spinal-induced hypotension episode was higher in patients who received ≥10 mg hyperbaric bupivacaine, 75.8% vs 62.9% for doses below 10 mg, P < .0001; however, even women with lower doses had hypotension. Hyperbaric bupivacaine dose <10 mg was associated with a lower incidence of spinal hypotension, adjusted odds ratio (OR) of 0.774, 95% confidence interval (CI), 0.669-0.897, and P = .0006, adjusted for confounding factors.Umbilical cord pH was available for 2684 (32.6%) cases. There were significantly more neonates with pH < 7.2, among women who received hyperbaric bupivacaine ≥10 mg (10.1%) versus women who received <10 mg (6.8%), P = .0032; however, in the adjusted model, hyperbaric bupivacaine dose ≥10 mg was not associated with pH < 7.2 and an OR of 0.955 (95% CI, 0.631-1.446, P = .829).

CONCLUSIONS

Our major finding was that hypotension occurred at all doses of hyperbaric bupivacaine, yet occurrence of spinal hypotension was significantly associated with doses ≥10 mg after adjustment for potential confounders.

The effect of spinal hypotension and anesthesia-to-delivery time interval on neonatal outcomes in planned cesarean delivery

BACKGROUND

Maternal hypotension after spinal anesthesia, and time from anesthesia to delivery, are potentially modifiable risk factors for neonatal acidosis.

OBJECTIVE

This study aimed to examine the relationship between the time from spinal anesthesia to delivery and spinal hypotension in planned cesarean deliveries and their effect on neonatal outcome, primarily neonatal acidosis.

STUDY DESIGN

We performed a retrospective analysis of women with singleton pregnancy undergoing spinal anesthesia for planned cesarean delivery between 37 0/7 and 41 6/7 weeks' gestation using electronic medical records. The occurrence of spinal hypotension and anesthesia-to-incision and incision-to-delivery intervals (minutes) were the primarily studied variables. In addition, spinal hypotension index was developed to account for the duration and magnitude of maternal hypotension. The 90th percentile for the spinal hypotension index defined the sustained spinal hypotension group. The primary outcome was neonatal acidosis (pH of ≤7.1 or base deficit of ≥12.0). The odds ratios were calculated using univariate and multivariate logistic regression models. The multivariate analysis included sporadic spinal hypotension or sustained spinal hypotension, use of vasopressor treatment, and anesthesia-to-incision and incision-to-delivery intervals.

RESULTS

We included 3150 women in the study. Notably, 43.4% experienced at least 1 event of spinal hypotension (sporadic) and 14.8% experienced sustained spinal hypotension. Neonatal acidosis occurred in 3.4% cases of sporadic spinal hypotension (odds ratio, 1.83; 95% confidence interval, 2.27-2.87) and in 5.8% cases of sustained hypotension (odds ratio, 3.00; 95% confidence interval, 1.87-4.80). Both anesthesia-to-incision and incision-to-delivery intervals were significantly associated with neonatal acidosis as follows: at 90th percentile cutoff, the odds ratios for neonatal acidosis were 3.82 (95% confidence interval, 2.03-7.19) and 2.94 (95% confidence interval, 1.70-5.10), respectively. The use of ephedrine (odds ratio, 2.42; 95% confidence interval, 1.35-4.32) but not phenylephrine (odds ratio, 0.76; 95% confidence interval, 0.34-1.72) treatment was also associated with more cases of neonatal acidosis. The woman's age, gestational age, neonatal birthweight, fetal presentation, and the number of previous cesarean deliveries were not associated with neonatal acidosis. In multivariate analysis, anesthesia-to-incision and incision-to-delivery intervals, use of vasopressor treatment, and sustained spinal hypotension were independently associated with neonatal acidosis. After adjustment, the risk for neonatal acidosis did not increase in women who experienced sporadic spinal hypotension only. Neither neonatal acidosis nor the primary research variables were associated with neonatal complications such as transient tachypnea of the newborn, respiratory distress, or admission to the neonatal unit.

CONCLUSION

Neonatal acidosis in planned cesarean delivery was common. However, serious perinatal consequences were rare. The adverse effects of sustained spinal hypotension and prolonged anesthesia-to-incision and incision-to-delivery intervals on neonatal acid-base balance were additive. This supports the adoption of prevention strategies for spinal hypotension, which is widely evidenced based on the obstetrical anesthesia literature, but still not universally used. Whether the reduction in intraoperative time intervals would benefit the neonate should be determined by future prospective studies.

Incidence and associated factors for hypotension after spinal anesthesia during cesarean section at Gandhi Memorial Hospital Addis Ababa, Ethiopia

Background

Spinal anesthesia is a type of regional anesthesia that has been practicing for obstetric anesthesia since the beginning of the 20th century. Despite the simplicity and lower maternal mortality risk, compared to general anesthesia, spinal anesthesia is linked to different adverse effects, of which hypotension is the most common complication. The main aim of this study was to determine the incidence and associated factors of hypotension after spinal anesthesia during cesarean section.

Method

Institution-based cross-sectional study was conducted with 410 clients. The study was conducted on cesarean section under spinal anesthesia from 5^th January to 30^th April 2019, at the Gandhi Memorial Hospital, Addis Ababa, Ethiopia. Both bivariable and multivariable logistic regression analysis were done on the associated factors. The level of statistical significance was represented at p<0.05.

Results

The incidence of hypotension among mothers who underwent a cesarean section after spinal anesthesia was 64%. Newborn weight ≥4kg (AOR = 5.373; 95%CI: (1.627–17.740)) showed an increase risk of association with hypotension. A baseline systolic blood pressure < 120mmHg (AOR = 6.293; (95%CI: 2.999–13.204)) was found to be associated with increased risk of hypotension. Sensory block height >T6 AOR = 2.230; 95%CI: (1.329–3.741), the time interval between spinal induction and skin incision > 6minutes AOR = 1.803; 95%CI: (1.044–3.114) and anesthetist experience AOR = 5.033(95%CI: 2.144–11.818) were also associated with hypotension.

Conclusion

The identified risk factors for hypotension, after spinal anesthesia are sensory height block, weight of the baby, the time interval between spinal induction and skin incision, baseline systolic blood pressure, and anesthetist experience.

Effects of isothermic crystalloid coload on maternal hypotension and fetal outcomes during spinal anesthesia for cesarean section: A randomized controlled trial

OBJECTIVE

Spinal anesthesia induced hypotension (SAIH) is a common occurrence during spinal anesthesia for cesarean section resulting in perturbing effects on maternal and fetal outcomes. Previous studies conducted to attenuate SAIH focused on the timing of intravenous fluid infusion and demonstrated the superiority of coload strategy on traditional preload strategy but neither of them focused on the effect of the temperature of crystalloid infused on SAIH and fetal outcomes. The current study aimed to assess the effect of the temperature of the crystalloid infused with coload strategy on the incidence of SAIH and fetal outcomes.

MATERIALS AND METHODS

Seventy-six parturients were enrolled into the study and data of 60 parturients were analyzed. Patients were randomly assigned to receive crystalloid coload at room temperature (Group RT, n = 30) or warmed at 37 °C (Group W, n = 30). The incidence of hypotension, cumulative hypotension episodes, heart rate, core body temperature, ephedrine dose, and fetal outcomes were recorded.

RESULTS

There was no significant difference in the incidence of maternal hypotension, cumulative hypotension episodes, and ephedrine dose (p = 0,625, p = 0,871, p = 0,460 respectively). Umbilical arterial pH and fetal Apgar scores at first and fifth minutes were higher in Group W than in Group RT (p = 0.013, p = 0.006 and p = 0.045 respectively). One fetus in Group RT but none in Group W had umbilical arterial pH lower than seven. Fetal birth weight and rectal temperature measurements were comparable in both groups (p = 0.639 and p = 0.675 respectively). Demographic data, patient characteristics, and surgery data were comparable between groups.

CONCLUSIONS

Isothermic crystalloid coload strategy results in higher umbilical pH values and Apgar scores in parturients scheduled for cesarean section under spinal anesthesia.

SPINAL ANAESTHESIA-INDUCED HYPOTENSION IN OBSTETRICS: PREVENTION AND THERAPY

Regional centro-axial anaesthesia, primarily spinal block, is the preferred method of anaesthesia for elective caesarean section because it entails fewer risks for the mother and the foetus compared to general anaesthesia. The most common side effect associated with spinal block is hypotension due to sympatholysis, occurring in up to 75% of cases. Spinal block-induced sympatholysis leads to vasodilatation and consequently causes maternal hypotension, which may compromise uterine blood flow and foetal circulation, and thus cause foetal hypoxia, bradycardia and acidosis. The selection of the most efficient treatment strategy to achieve haemodynamic stability during spinal anaesthesia for caesarean section continues to be one of the main challenges in obstetric anaesthesiology. A number of measures for the prevention and treatment of spinal block-induced hypotension are used in clinical practice, such as preloading and coloading with crystalloid and/or colloid infusion, wrapping of lower limbs with compression stockings or bandages, administering an optimal dose of local anaesthetic and achieving an optimal spinal block level, left tilt positioning, and administering inotropes and vasopressors. Instead of administering vasopressors after a drop in blood pressure has already occurred, the latest algorithms recommend a prophylactic administration of vasopressor infusion. The preferred vasoconstrictor in this case is phenylephrine, which is associated with a lower incidence of foetal acidosis, and maternal nausea and vomiting compared to other vasoconstrictors.

Time from neuraxial anesthesia placement to delivery is inversely proportional to umbilical arterial cord pH at scheduled cesarean delivery

BACKGROUND

Neuraxial block-related hypotension and maternal obesity contribute to uterine hypoperfusion and decreased umbilical arterial pH at cesarean delivery. Between the time of anesthesia placement and delivery, the fetus may be exposed to a hypoperfused uterine environment without surgeon awareness of fetal compromise.

OBJECTIVE

We sought to evaluate neonatal umbilical arterial pH according to predelivery time intervals at scheduled term cesarean.

STUDY DESIGN

We performed a retrospective cohort study of cesarean deliveries between September 2014 and February 2017. Singleton gestations undergoing scheduled cesarean delivery under spinal anesthesia between 37 and 41 weeks with a reassuring preoperative nonstress test were included. Time intervals between operative room entry, spinal anesthesia placement, skin incision, uterine incision, and delivery were calculated. The primary outcome was umbilical arterial pH. Demographic data, maternal blood pressures, predelivery time intervals, and delivery outcomes were analyzed according to umbilical arterial pH intervals of <7.0, 7.01-7.10, 7.11-7.20, 7.21-7.30, and >7.30. Umbilical cord gas analytes and neonatal outcomes were analyzed by spinal to delivery time. Stepwise linear regression was performed to identify predictors of decreasing umbilical arterial pH. Receiver-operator characteristic curves were calculated for spinal to delivery time and umbilical arterial pH <7.0 and 7.1.

RESULTS

Among 527 included participants, median umbilical arterial pH was 7.27 [interquartile range, 7.23-7.29] and body mass index was 35 kg/m² [interquartile range, 30-41]. Both maternal body mass index and hypotensive episodes increased with decreasing umbilical arterial pH (P <.001, P ≤ .02). All predelivery time intervals (operative room to delivery, spinal to skin, spinal to delivery, and uterine incision to delivery) increased as umbilical arterial pH interval decreased (P < .05 for all). In a stepwise linear regression, maternal body mass index, noncephalic presentation, spinal start to delivery interval, uterine incision to delivery interval, and maximum reduction in blood pressure from baseline were predictive of decreasing umbilical arterial pH after controlling for confounding variables (F [5,442] = 17.7, P = .0001], adjusted R² of 0.157. When evaluated by spinal to delivery time, both umbilical arterial and venous pH and partial pressure of carbon dioxide decreased (P < .001 for all), but base deficit and neonatal outcomes were similar (P ≥ .7 for all). There were 2 cases of hypoxic-ischemic encephalopathy (0.38%). A receiver-operating characteristic curve demonstrated that a spinal start to delivery time greater than 27 minutes was associated with an umbilical arterial pH <7.1 (area under the curve, 0.74, 100% sensitivity, 21% specificity), and an interval greater than 30 minutes was associated with an umbilical arterial pH <7.0 (area under the curve, 0.80, 100% sensitivity, 33% specificity).

CONCLUSION

Longer spinal-to-delivery and uterine incision-to-delivery time intervals were associated with decreasing umbilical arterial pH at scheduled term cesarean delivery. Efforts to minimize predelivery time following spinal placement could reduce the frequency of unanticipated neonatal acidemia.

Crystalloid coloading vs. colloid coloading in elective Caesarean section: postspinal hypotension and vasopressor consumption, a prospective, observational clinical trial

BACKGROUND

Maternal hypotension is a common side effect of spinal anaesthesia for Caesarean section. The combination of colloid coloading and vasopressors was considered our standard for its prevention and treatment. As the safety of hydroxyethyl starch is under debate, we replaced colloid with crystalloid coloading.

OBJECTIVE

We hypothesize that the mean blood pressure drop is greater when coloading with crystalloids.

DESIGN

Prospective, observational clinical trial.

SETTING

Two-centre study conducted in Berlin, Germany.

PATIENTS

Parturients scheduled for a Caesarean section were screened for eligibility.

INTERVENTION

The study protocol and patient monitoring were based on the standard operating procedure for Caesarean section in both centres. The data from the crystalloid group were prospectively collected between November 2014 and July 2015.

MAIN OUTCOME MEASURES

The primary endpoint was the median drop in mean blood pressure after induction of spinal anaesthesia. Secondary endpoints were incidence of hypotension (drop > 20% of baseline systolic pressure /drop < 100 mmHg), vasopressor and additional fluid requirements (mL), incidence of bradycardia (heart rate < 60 beats per minute), blood loss, Apgar score, and umbilical artery pH. In case of hypotension, patients received phenylephrine or cafedrine/theodrenaline according to their heart rate. A p < 0.05 was considered significant.

RESULTS

345 prospectively enrolled patients (n = 193 crystalloid group vs. n = 152 colloid group) were analysed. The median drop in mean blood pressure was greater in the crystalloid group [34 mmHg (25; 42 mmHg) vs. 21 mmHg (13; 29 mmHg), p < 0.001]. Incidences of hypotension [93.3% vs. 83.6%, p: 0.004] and bradycardia [19.7% vs. 9.9%, p: 0.012] were also significantly greater in the crystalloid group. Vasopressor requirements, blood loss and neonatal outcome were not different between the groups.

CONCLUSIONS

Crystalloid coloading was associated with a greater drop in mean blood pressure and a higher incidence of hypotension when compared with colloid coloading. Neonatal outcome was, however, unaffected by the type of fluid.

TRIAL REGISTRATION

DRKS00006783 ( http://www.drks.de ).

Effect of anaesthetic technique on neonatal morbidity in emergency caesarean section for foetal distress

Background

While foetal distress is typically associated with ischaemic injury, few studies have assessed neonatal morbidity for emergency caesarean section. Moreover, the decision of the anaesthetic technique may be of paramount importance in emergency caesareans, because of the limited time and increased risk. We aimed to evaluate the effect of the anaesthetic technique on neonatal morbidity in emergency caesarean indicated for foetal distress.

Methods

This was a single-centre, prospective observational study, conducted between July-2015 and December-2015. The study enrolled parturient with indication for emergency caesarean section after diagnosis of foetal distress, who received either regional or general anaesthesia. The outcome measures were: 1, 5-minute Apgar scores; umbilical blood pH; length of hospitalization; and morbidity, defined as a 5-minute Apgar score <7, need for mechanical ventilation, admittance to a neonatal intensive care unit, or respiratory insufficiency symptoms.

Results

61 patients were included in the study, of whom 31 received regional anaesthesia. Neonatal morbidity was noted in 5 and 9 cases with regional and general anaesthesia, respectively. The 1-minute Apgar score was significantly lower(p = 0,045) for cases with general anaesthesia, which was not true for the 5-minute Apgar score. Regional anaesthesia was non-significantly associated with shorter length of hospitalization, lower incidence of morbidity, and higher umbilical blood pH. When we take regional anaesthesia cases as a reference point, we detected that general anaesthesia cases are showing 2,2 times more morbidity risk. But these results did not reach any statistically significant levels.

Conclusions

While we did find some improved results for regional anaesthesia group, we found no statistical evidence that neither anaesthesia technique is superior regarding neonatal morbidity. We think that regional anaesthesia should be preferred whenever possible because of our improved results of length of hospital stay, APGAR and morbidity and we think that general anaesthesia is indicated for very urgent cases or regional anaesthesia contraindicated patients.

Trial registration

http://www.isrctn.com/ISRCTN15181117

Maternal and anaesthesia-related risk factors and incidence of spinal anaesthesia-induced hypotension in elective caesarean section: A multinomial logistic regression

BACKGROUND AND AIMS

Although spinal anaesthesia (SA) is nowadays the preferred anaesthesia technique for caesarean section (CS), it is associated with considerable haemodynamic effects, such as maternal hypotension. This study aimed to evaluate a wide range of variables (related to parturient and anaesthesia techniques) associated with the incidence of different degrees of SA-induced hypotension during elective CS.

METHODS

This prospective study was conducted on 511 mother-infant pairs, in which the mother underwent elective CS under SA. The data were collected through preset proforma containing three parts related to the parturient, anaesthetic techniques and a table for recording maternal blood pressure. It was hypothesized that some maternal (such as age) and anaesthesia-related risk factors (such as block height) were associated with occurance of SA-induced hypotension during elective CS.

RESULTS

The incidence of mild, moderate and severe hypotension was 20%, 35% and 40%, respectively. Eventually, ten risk factors were found to be associated with hypotension, including age >35 years, body mass index ≥25 kg/m2, 11-20 kg weight gain, gravidity ≥4, history of hypotension, baseline systolic blood pressure (SBP) <120 mmHg and baseline heart rate >100 beats/min in maternal modelling, fluid preloading ≥1000 ml, adding sufentanil to bupivacaine and sensory block height >T4in anaesthesia-related modelling (P < 0.05).

CONCLUSION

Age, body mass index, weight gain, gravidity, history of hypotension, baseline SBP and heart rate, fluid preloading, adding sufentanil to bupivacaine and sensory block hieght were the main risk factors identified in the study for SA-induced hypotension during CS.

Reducing by 50% the incidence of maternal hypotension during elective caesarean delivery under spinal anesthesia: Effect of prophylactic ondansetron and/or continuous infusion of phenylephrine - a double-blind, randomized, placebo controlled trial

Background:

Prophylactic administrations of ondansetron or phenylephrine have been reported to provide a protective effect against hypotension in women undergoing cesarean delivery under spinal anesthesia (SA). The main hypothesis is that ondansetron improves the hemodynamic response, especially combined with phenylephrine infusion.

Methods:

This prospective, double-blind, randomized, placebo-controlled study included 265 healthy pregnant women scheduled for elective cesarean delivery under SA. Women were randomly allocated into four groups to receive either placebo (control), ondansetron (O) 8 mg intravenously before induction of SA, phenylephrine infusion (50 mcg/min) (P) or ondansetron plus phenylephrine (OP). Demographic, obstetric, intraoperative timing, and anesthetic variables were assessed at 16 time points. Anesthetic variables assessed included blood pressure, heart rate, oxygen saturation, nausea, vomiting, electrocardiographic changes, skin flushing, discomfort or pruritus, and vasopressor requirements.

Results:

There were differences (P = 0.0001) in the number of patients with hypotension (50.8% control, 44.6% O, 20.9% P, 25.0% OP), the percentage of time points (P = 0.0001) with systolic hypotension per patient (17.4% control, 8.7% O, 2.1% P, 6.7% OP) and the number of patients requiring supplementary boluses of ephedrine (P = 0.003), phenylephrine (P = 0.017) or atropine (P = 0.0001).

Conclusions:

A 50 μg/min phenylephrine infusion reduces by 50%, the incidence of maternal hypotension compared with placebo, but infusions of phenylephrine are still not routine in our environment. Prophylactic ondansetron 8 mg might be considered in this situation, because it does not reduce the incidence of maternal hypotension but diminishes its severity, reducing the number of hypotensive events per patient by 50%.

Spinal versus general anesthesia for Cesarean section in patients with sickle cell anemia

Background

Sickle cell anemia (SCA) increases the rate of maternal and fetal complications. This pilot study was designed to compare the maternal and fetal outcomes of spinal versus general anesthesia (GA) for parturients with SCA undergoing cesarean delivery.

Methods

Forty parturients with known SCA scheduled for elective Cesarean delivery were randomized into spinal anesthesia (n = 20) and GA groups (n = 20). Perioperative hemodynamic parameters were recorded. Postpartum complications were followed up. Opioid consumption was calculated. Blood loss during surgery and the number of patients who received intraoperative or postpartum blood transfusion were recorded. Patient satisfaction with the type of anesthesia was assessed. The Apgar score at 1 and 5 min, neonatal admission to the intensive care unit, and mortality were also recorded.

Results

Blood loss was significantly higher in the GA than spinal group (P = 0.01). However, the number of patients who received an intraoperative or postpartum blood transfusion was statistically insignificant. Significantly more patients developed intraoperative hypotension and bradycardia in the spinal than GA group. Opioid use during the first 24 h was significantly higher in the GA than spinal group (P < 0.0001). More patients had vaso-occlusive crisis in the GA than spinal group without statistical significance (P = 0.4). There was one case of acute chest syndrome in the GA group. No significant differences were observed in postoperative nausea and/or vomiting, patient satisfaction, or hospital length of stay. Neonatal Apgar scores were significantly better in the spinal than GA group at 1 and 5 min (P = 0.006 and P = 0.009, respectively). Neonatal intensive care admission was not significantly different between the two groups, and there was no neonatal mortality.

Conclusions

Spinal anesthesia may have advantages over GA in parturients with SCA undergoing Cesarean delivery.

Comparison of maternal and fetal outcomes among patients undergoing cesarean section under general and spinal anesthesia: a randomized clinical trial

CONTEXT AND OBJECTIVE

As the rates of cesarean births have increased, the type of cesarean anesthesia has gained importance. Here, we aimed to compare the effects of general and spinal anesthesia on maternal and fetal outcomes in term singleton cases undergoing elective cesarean section.

DESIGN AND SETTING

Prospective randomized controlled clinical trial in a tertiary-level public hospital.

METHODS

Our study was conducted on 100 patients who underwent cesarean section due to elective indications. The patients were randomly divided into general anesthesia (n = 50) and spinal anesthesia (n = 50) groups. The maternal pre and postoperative hematological results, intra and postoperative hemodynamic parameters and perinatal results were compared between the groups.

RESULTS

Mean bowel sounds (P = 0.036) and gas discharge time (P = 0.049) were significantly greater and 24th hour hemoglobin difference values (P = 0.001) were higher in the general anesthesia group. The mean hematocrit and hemoglobin values at the 24th hour (P = 0.004 and P < 0.001, respectively), urine volume at the first postoperative hour (P < 0.001) and median Apgar score at the first minute (P < 0.0005) were significantly higher, and the time that elapsed until the first requirement for analgesia was significantly longer (P = 0.042), in the spinal anesthesia group.

CONCLUSION

In elective cases, spinal anesthesia is superior to general anesthesia in terms of postoperative comfort. In pregnancies with a risk of fetal distress, it would be appropriate to prefer spinal anesthesia by taking the first minute Apgar score into account.

Co-loading or pre-loading for prevention of hypotension after spinal anaesthesia! a therapeutic dilemma

Neuraxial blockade such as spinal anaesthesia can cause severe hypotension due to pharmacological sympathectomy resulting in potential deleterious consequences for the patient. Prevention of this spinal anaesthesia induced hypotension is of utmost importance especially in pregnant population as the life of mother as well as fetus is at risk. Several techniques and methodologies have been adopted for the prevention of this neuraxial hypotension with varying degree of success. The administration of intravenous fluids to optimize the blood volume during sympathectomy has been the most popular and widely used as the first line of therapy among these techniques. The intravenous fluids can be used both before and during the administration of spinal anaesthesia, the techniques appropriately named as pre-loading and co-loading respectively. Numerous research studies and available literary evidence suggests that both of these techniques can be equally effective in prevention of hypotension. The use of colloids has been observed to be more effective for pre-loading due to their longer half-life in the intravascular compartment. However, it has also been suggested that no technique is efficient in preventing the hypotension alone and has to be coupled with judicious use of vasopressors.

Update on volume therapy in obstetrics

Symptomatic hypotension (maternal nausea, vomiting, dizziness and dyspnoea) during spinal anaesthesia for caesarean delivery remains a prevalent clinical problem. Severe and sustained hypotension can lead to impairment of uteroplacental perfusion, foetal hypoxia, acidosis, neonatal depression and further adverse maternal outcomes of unconsciousness, pulmonary aspiration, apnoea and cardiac arrest. Mechanical methods aimed at countering the effects of aortocaval compression do not reliably prevent maternal hypotension. Intravenous crystalloid preloading (given prior to administration of spinal anaesthesia) has poor efficacy, and focus has changed towards decreased use of crystalloid preload and ephedrine, to increased use of coload (given at the time of spinal administration) with colloids or crystalloids, and early use of phenylephrine. The recent multicentre, randomised, double-blinded CAESAR trial demonstrated the efficacy of a mixed 500 ml 6% hydroxyethyl starch (HES) 130/0.4 + 500 ml Ringer's lactate (RL) preload in significantly reducing hypotension, compared to a 1-l RL preload, without adverse effects on coagulation and neonatal outcomes in healthy parturients undergoing caesarean delivery under spinal anaesthesia.

The median effective seated time for hypotension induced by spinal anesthesia at Cesarean delivery with two doses of hyperbaric bupivacaine: a randomized up-down sequential allocation study

BACKGROUND

Extending the time a parturient is left sitting after induction of spinal anesthesia (i.e., the seated time) has had varying success in decreasing hypotension at Cesarean delivery. This may be due to the current lack of information concerning the dose-response relationship of seated time and rates of hypotension.

METHODS

Term parturients scheduled for Cesarean delivery were randomized to receive 11.25 or 15.0 mg of 0.75% intrathecal hyperbaric bupivacaine, and they remained seated after injection for a length of time determined by an up-down sequential method. They were then placed in a wedged position and their blood pressure was measured every minute. Pre-delivery hypotension was considered present if there was a > 20% from baseline drop in systolic blood pressure. The seated time at which 50% of parturients avoided pre-delivery hypotension (median effective seated time) was determined with isotonic regression.

RESULTS

Fifty patients were studied. For the 11.25-mg and 15.0-mg groups, the median effective seated time (95% confidence interval [CI]) was 130 sec (95% CI 117 to 150) and 385 sec (95% CI 381 to 396), respectively.

CONCLUSIONS

There exists a seated time after intrathecal injection of hyperbaric bupivacaine where 50% of parturients do not experience hypotension. This seated time increases with an increased dose of bupivacaine. Further work is required to determine the full relationship between seated time and hypotension for other doses of anesthetic and to investigate the clinical utility of this technique for prevention of hypotension. This trial was registered at www.clinicaltrials.gov (NCT01561274).

Determinants of neonatal blood pressure

Blood pressure (BP) measurements have been increasingly used across neonatal intensive care units to determine and monitor hemodynamic status in neonates. A number of studies have attempted to derive normative blood pressure data in both preterm and term infants. However, this still remains a complex process, as several maternal and neonatal factors influence neonatal blood pressure. Maternal conditions, including hypertension and preeclampsia, seem to have some impact on neonatal BP, while maternal drugs, in particular antenatal steroids, seem to have a strong influence. Among the neonatal factors, gestational age, post-conceptual age and weight seem to have the strongest influence. The paucity of data on the short and long term effects of maternal conditions and medication on neonatal BP requires further research.

Anesthetic considerations in pregnant women at advanced maternal age

OBJECTIVE

To evaluate anesthetic considerations in pregnancy for women at advanced maternal age (≥40 years).

METHODS

A retrospective cohort study of laboring women aged 40 years or above comparing women aged 40-44 years old with those aged ≥45 years, in a single, tertiary, university affiliated medical center.

RESULTS

Overall, 39,006 women delivered in our institution during the study period, of them 376 (1%) were eligible for analysis: 278 (74%) were 40-44 years old (control group) and 98 (26%) were 45 years old and above (study group). No differences were found between the groups with regards to analgesia or anesthesia management during labor. Differences were found in obstetrical characteristics such as higher rates of primiparity, preeclampsia, need for magnesium sulphate therapy and chronic hypertension among parturients aged ≥45 years. Of note, parturients aged ≥ 45 years had an approximately eight-fold risk for postpartum hemorrhage.

CONCLUSION

Anesthesia management of parturients aged 45 years and above is comparable to the management of women aged 40-44 years. However, parturients≥45 are more susceptible to bleeding complications.

The median effective volume of crystalloid in preventing hypotension in patients undergoing cesarean delivery with spinal anesthesia

BACKGROUND AND OBJECTIVES

Spinal anesthesia-associated maternal hypotension in Cesarean delivery is the most frequent and troublesome complication, posing serious risks to mothers and compromising neonatal well-being. The effective volume of intravenous crystalloid as the preventive strategy in this context has not been estimated.

METHODS

Eighty-five parturients with ASA physical status I/II undergoing elective Cesarean delivery were screened and 67 eligible women were assigned to receive pre-spinal crystalloid loading. Hyperbaric 0.5% bupivacaine 2mL (10mg) plus morphine 50μg was given to all patients. The volume of crystalloid was determined by an up-and-down sequential method. The crystalloid was infused at a rate of 100-150mL.min(-1) prior to the spinal anesthetic injection. The initial volume of crystalloid was 5mL.kg(-1). Volume-effect data were fitted to a sigmoidal maximum efficacy model and the median effective volume (EV(50)) and corresponding 95% confidence interval (95% CI) were estimated using maximum likelihood estimation and logistic regression with Firth's correction.

RESULTS

A total of 67 subjects completed the study and were analyzed. Twenty-eight (41.8%) patients developed hypotension with their systolic blood pressure (SBP) decreasing > 20% of baseline. The EV(50) of crystalloid were 12.6mL.kg(-1) (95% CI, 11.6 to 14.8mL.kg(-1)). With Firth's correction, the pooled probability of an effective preventive volume of crystalloid at 13mL.kg(-1) was 50.2% (95% CI, 30% to 83.1%).

CONCLUSIONS

The estimated EV(50) of the preloaded crystalloid required to prevent spinal anesthesia-induced hypotension in a Cesarean section is, approximately, 13mL.kg(-1). However, prophylactic or therapeutic vasoconstrictors should also be prepared and administered at an appropriate time.

Caesarean delivery vasopressor management

PURPOSE OF REVIEW

This review assesses the maternal and fetal effects of vasopressor administration during spinal anaesthesia for caesarean delivery, with emphasis on recent findings.

RECENT FINDINGS

Maternal heart rate is a good surrogate for cardiac output. The initial hypotensive effect of spinal anaesthesia is caused by a rapid decrease in systemic vascular resistance, which makes α-agonists the logical first-line therapy. Effective prophylactic phenylephrine administration can be associated with reduced maternal cardiac output, but this has not been associated with adverse maternal or fetal effects. Prophylactic phenylephrine infusion can cause hypertension if increasing arterial pressure does not trigger a timely reduction in the rate of administration. Phenylephrine has been used safely in mothers with cardiac disease and in pregnancies with suspected fetal compromise. Fetal genotype may increase resistance to ephedrine-induced acidosis. The combination of vagolytics and vasopressors has caused maternal hypertensive crises with serious adverse outcome.

SUMMARY

Phenylephrine is the current vasopressor of choice for the prevention of maternal hypotension and nausea. Phenylephrine regimens need to be developed that can reliably and safely be used with noninvasive blood pressure cycle times less frequent than every minute. Further vasopressor should be used with caution when vagolytic therapy is, quite rightly, used to treat bradycardia associated with hypotension.

Effects of sitting up for five minutes versus immediately lying down after spinal anesthesia for Cesarean delivery on fluid and ephedrine requirement; a randomized trial

BACKGROUND

Patient position after spinal anesthesia has had variable effects on blood pressure and ephedrine requirements. The aim of this study was to determine the effects that sitting the patient up for five minutes after spinal anesthesia would have on intraoperative fluid and ephedrine requirements.

METHODS

The study included 120 women at term gestation who were scheduled for Cesarean delivery under spinal anesthesia. After anesthetic administration, the women were randomized either to sit up for five minutes then lie down (Group S) or to lie down immediately (Group L) to a tilted supine position. A blinded observer recorded sensory block level, systolic blood pressure, heart rate, ephedrine and fluid requirements, adverse events, and time to motor recovery (modified Bromage score of 2).

RESULTS

Group S had a lower intraoperative sensory block height than Group L [T4 (1) vs T2 (1), respectively; P < 0.001]; Group S also required less ephedrine (8% vs 47%, respectively; P < 0.001), received less fluid [709 (59) mL vs 789 (90) mL, respectively; P < 0.001], and experienced less nausea and vomiting (5% vs 22%, respectively; P = 0.014) and shortness of breath (3% vs 28%, respectively; P < 0.001) intraoperatively. In Group S, the odds of requiring ephedrine were 0.09 compared with 0.89 in Group L (odds ratio 0.10). There were no differences in systolic blood pressure (P = 0.127) or heart rate (P = 0.831) over time between groups. Time to a modified Bromage score of 2 was longer in Group S than in Group L [101 (15) min vs 88 (14) min, respectively; P < 0.001].

CONCLUSIONS

Sitting the patient up for five minutes rather than laying the patient down immediately after spinal anesthesia for Cesarean delivery decreased intraoperative sensory block height, ephedrine and fluid requirements, and intraoperative nausea, vomiting, and shortness of breath without affecting systolic blood pressure or the success of the anesthetic. However, the method resulted in delayed postoperative motor recovery.

Prevention of maternal hypotension after regional anaesthesia for caesarean section

PURPOSE OF REVIEW

Hypotension during regional anaesthesia for caesarean section remains a common clinical problem, particularly for spinal anaesthesia. The purpose of this review is to evaluate recent research in this area with a focus on English language papers from the past 1-2 years.

RECENT FINDINGS

Risk factors for hypotension include increased sympathetic tone, increasing age, obesity, higher blocks and higher birthweight, but not multiple gestation. Methods aimed at countering effects of aortocaval compression do not reliably prevent hypotension. Intravenous crystalloid prehydration has poor efficacy, and focus has changed toward cohydration and use of colloids. Phenylephrine is established as a first-line vasopressor, although there are limited data from high-risk patients. Initial phenylephrine bolus dose requirement may be surprisingly large. Phenylephrine infusions can be conveniently titrated to maintain blood pressure and prevent maternal symptoms. Ephedrine crosses the placenta more than phenylephrine and direct fetal effects of ephedrine may explain associated depression of fetal pH and base excess.

CONCLUSION

Recent research supports decreased use of crystalloid prehydration and ephedrine and increased use of cohydration, colloids, smaller spinal doses and phenylephrine. Further research is required to investigate these techniques in high-risk patients and to evaluate novel monitoring techniques.