Left Lateral Table Tilt for Elective Cesarean Delivery under Spinal Anesthesia Has No Effect on Neonatal Acid–Base Status

Intravenous initial bolus during prophylactic norepinephrine infusion to prevent spinal hypotension for cesarean delivery: A randomized controlled, dose-finding trial

BACKGROUND

Previous studies have shown that a 0.05 μg/kg/min of norepinephrine infusion in combination with an initial bolus reduces the incidence of spinal hypotension during cesarean delivery. The initial norepinephrine bolus influences the incidence of spinal hypotension during continuous norepinephrine infusion; however, the ideal initial bolus dose for 0.05 μg/kg/min of continuous infusion remains unknown.

METHODS

This randomized, controlled, dose-finding study randomly allocated 120 parturients scheduled for elective cesarean delivery to receive initial bolus doses of 0, 0.05, 0.10, and 0.15 μg/kg of norepinephrine, followed by continuous infusion at a rate of 0.05 μg/kg/min. The primary outcome was the dose-response relationship of the initial norepinephrine bolus in preventing the incidence of spinal hypotension. Spinal hypotension was defined as systolic blood pressure (SBP) decreased to <80% of the baseline value or to an absolute value of <90 mmHg from intrathecal injection to delivery, and severe spinal hypotension was defined as SBP decreased to <60% of the baseline value. The secondary outcomes included the incidence of nausea and/or vomiting, hypertension, and bradycardia, as well as the Apgar scores and results of the umbilical arterial blood gas analysis. The effective dose (ED) 90 and ED95 were estimated using probit regression.

RESULTS

The per-protocol analysis included 117 patients. The incidence of spinal hypotension varied significantly among the groups: Group 0 (51.7%), Group 0.05 (44.8%), Group 0.10 (23.3%), and Group 0.15 (6.9%). The ED90 and ED95 values were 0.150 μg/kg (95% confidence interval [CI], 0.114-0.241 μg/kg) and 0.187 μg/kg (95% CI, 0.141-0.313 μg/kg), respectively. However, the ED95 value fell outside the dose range examined in this study. The incidence of severe spinal hypotension differed significantly (P = 0.02) among Groups 0 (17.2%), 0.05 (10.3%), 0.10 (3.3%), and 0.15 (0.0%); however, the incidence of hypertension and bradycardia did not. The incidence of nausea and/or vomiting decreased with an increase in the initial bolus dose (P = 0.03). The fetal outcomes were comparable among the groups.

CONCLUSIONS

An initial bolus of 0.150 μg/kg of norepinephrine may be the optimal dose for preventing spinal hypotension during cesarean delivery with a continuous infusion rate of 0.05 μg/kg/min, and does not significantly increase the incidence of hypertension but substantially reduces the risk of nausea and/or vomiting.

Anesthetic recommendations for maternal and fetal safety in nonobstetric surgery: a balancing act

PURPOSE OF REVIEW

Nonobstetric surgery during pregnancy is associated with maternal and fetal risks. Several physiologic changes create unique challenges for anesthesiologists. This review highlights physiologic changes of pregnancy and presents clinical recommendations based on recent literature to guide anesthetic management for the pregnant patient undergoing nonobstetric surgery.

RECENT FINDINGS

Nearly every anesthetic technique has been safely used in pregnant patients. Although it is difficult to eliminate confounding factors, exposure to anesthetics could endanger fetal brain development. Perioperative fetal monitoring decisions require an obstetric consult based on anticipated maternal and fetal concerns. Given the limitations of fasting guidelines, bedside gastric ultrasound is useful in assessing aspiration risk in pregnant patients. Although there is concern about appropriateness of sugammadex for neuromuscular blockade reversal due its binding to progesterone, preliminary literature supports its safety.

SUMMARY

These recommendations will equip anesthesiologists to provide safe care for the pregnant patient and fetus undergoing nonobstetric surgery.

MRI of caval compression during left-lateral tilt in singleton and twin pregnancies: A prospective cohort study

BACKGROUND

It is unclear how different degrees of left-lateral tilt affect the volumes of the abdominal aorta and inferior vena cava (IVC) in pregnancy.

OBJECTIVE

To use magnetic resonance images to assess the volumes of the abdominal aorta and IVC in women with twin or singleton pregnancies in different degrees of left-lateral tilt.

DESIGN

Prospective cohort study.

SETTING

A single-centre university hospital.

PATIENTS

Women with singleton pregnancies (13) and twin pregnancies (13) at 32 to 38 weeks' gestation.

MAIN OUTCOME MEASURES

Comparison of abdominal aortic and IVC volumes measured by MRI in women with singleton and twin pregnancies while in the supine or left-lateral tilt position at 15°, 30° and 45°.

RESULTS

Supine, the mean aortic and IVC volumes were not significantly different between the women with singleton and twin pregnancies. In a left-lateral tilt position of 15 o compared with supine, the mean IVC volume was not increased in either group (singletons: 6.3 ± 6.6 ml, 95% CI, -2.4 to 0.4; P  = 0.174; twins: 3.9 ± 2.4 ml, 95% CI, -2.6 to 0.4; P  = 0.138). At tilt angles of 30° or 45°, the mean IVC volume significantly increased (singletons 30°: 9.7 ± 5.8 ml, 95% CI, -6.1 to -2.7; P  < .001; singleton 45°:13.8 ± 5.0 ml, 95% CI, -11.3 to -5.7; P  < .001; twins 30°: 5.7 ± 2.1 ml, 95% CI, -4.0 to -1.4; P  < .001; twins 45°: 12.8 ± 9.4 ml, 95% CI, -17.2 to -2.6; P  = 0.003). Aortic volume was not significantly increased in either group at any of the examined tilt angles compared with the supine.

CONCLUSION

IVC volume is significantly increased by 30° and 45° left-lateral tilt positions compared with supine in women with singleton and twin pregnancies.

TRIAL REGISTRATION

This study was registered in the University Hospital Medical Information Network (UMIN) clinical trial registration (# UMIN000031273).

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.

Neonatal outcomes when intravenous esketamine is added to the parturients transferred from labor analgesia to emergency cesarean section: a retrospective analysis report

OBJECTIVES

The use of intravenous analgesics during emergency cesarean section may lead to adverse neonatal outcomes. In our study, we investigated whether a single intravenous (i.v.) dose of 25 mg esketamine administered to parturients with inadequate analgesia during epidural anesthesia for cesarean section would affect the neonate.

DESIGN

We reviewed the records of parturients who were transferred from labor analgesia to epidural anesthesia for emergency cesarean section from January 2021 to April 2022. Parturients were grouped by whether they received esketamine infusions during the incision-delivery interval. Neonatal outcomes, including umbilical arterial-blood gas analysis (UABGA), Apgar score, and total days spent by the neonate in the hospital, were compared between the two groups. The secondary outcomes of this study included BP, heart rate (HR), SPO₂ and the incidence of adverse effects in parturients during operation.

SETTING

China.

RESULTS

After propensity score matching, 31 patients remained in each of the non-esketamine and esketamine groups. There were no significant differences in neonatal outcomes, including UABGA, Apgar score, and total days in the hospital, between the two groups. Additionally, our study showed a similar hemodynamic performance in parturients between the two groups during operation.

CONCLUSIONS

Intravenous esketamine (25 mg) is safe for neonates when it is given to parturients transferred from labor analgesia to emergency cesarean section.

Anesthesia characteristic of an algorithm of bupivacaine dose based on height in caesarean section under spinal anesthesia: a retrospective cohort study

BACKGROUND

An algorithm of bupivacaine dose based on height is applied to reduce maternal hypotension in caesarean section under spinal anesthesia. This study is designed to further verify whether the algorithm of bupivacaine dose based on height is suitable.

METHODS

The parturients were grouped according to height. The comparison of anesthesia characteristic among subgroups was carried out. The univariate and multivariate binary logistic regressions were executed to reanalyze the interference factor for the anesthesia characteristic.

RESULTS

When the dose of bupivacaine was adjusted by using the height based dosing algorithm, except for weight (P < 0.05), other general data did not present statistical changes with height (P > 0.05); the incidences of complications, characteristics of sensory or motor block, quality of anesthesia and neonatal outcome were of no statistical difference among parturients with different heights (P > 0.05); the height, weight and body mass index were not related with maternal hypotension (P > 0.05). When the dose of bupivacaine is constant, except for weight and body mass index (P > 0.05), the height was the independent risk factor for maternal hypotension (P < 0.05).

CONCLUSIONS

Except for weight and body mass index, the height has an influence on the bupivacaine dose. It is reasonable that the bupivacaine dose is adjusted by using this dosing algorithm based on height.

TRIAL REGISTRATION

This study was registered at http://clinicaltrials.gov (13/04/2018, NCT03497364).

Der Mythos der 15°-Linksseitenlagerung zur Entlastung der Vena cava inferior

Positioning the pregnant patient in her third trimester in a 15° left lateral tilt position with the rationale to reduce inferior vena cava (IVC) compression is a longstanding practice of both obstetric and anesthesia care. Recent data from MRI imaging studies have challenged this traditional dogma, since the IVC was found to remain compressed at a 15° angle, with a tilt of at least 30° necessary to provide a certain relief of the vessel. However, even the 15° tilt is regularly underestimated by visual judgement and improperly executed, but comes with several disadvantages without adding any benefit on fetal outcome. Current evidence supports all efforts to cease the dogma of a 15° left lateral position for its lack of effectiveness and instead put emphasis on proven measures, such as volume coloading and the timely administration of vasopressors.

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.

Impact of maternal lateral tilt on cardiac output during caesarean section under spinal anaesthesia: a prospective observational study

BACKGROUND

Left uterine displacement (LUD) has been questioned as an effective strategy to prevent aortocaval compression after spinal anesthesia (SA) for cesarean delivery (CD). We tested if LUD has a significant impact on cardiac output (CO) in patients undergoing CD under SA during continuous non-invasive hemodynamic monitoring with Clearsight.

METHODS

Forty-six patients were included in the final analysis. We considered 4 timepoints of 5 min each: T1 = baseline with LUD; T2 = baseline without LUD; T3 = after SA with LUD; T4 = after SA without LUD. LUD was then repositioned for CD. The primary outcome was to assess if CO decreased from T3 to T4 of at least 1.0 L/min. We also compared CO between T1 and T2 and other hemodynamic variables: mean, systolic and diastolic blood pressure (respectively MAP, SAP and DAP), heart rate (HR), stroke volume (SV), stroke volume variation (SVV), pulse pressure variation (PPV), contractility (dP/dt), dynamic arterial elastance (Ea_dyn) at the different timepoints. Data on fetal Apgar scores and umbilical arterial and venous pH were collected.

RESULTS

CO did not vary from T3 to T4 (CO mean difference -0.02 L/min [95% CI -0.88 to 0.82; P = 1). No significant variation was registered for any variable at any timepoint.

CONCLUSIONS

LUD did not show a significant impact on CO during continuous hemodynamic monitoring after SA for CD.

TRIAL REGISTRATION

(retrospectively registered on 03/12/2021) NCT05143684 .

Surgery in the Obese Pregnant Patient

This chapter reviews issues which complicate surgery in obese pregnant patients. Maternal obesity is prevalent in the United States and is associated with numerous adverse health outcomes. When surgery is indicated during pregnancy, the presence of maternal obesity increases surgical risks for both the fetus and mother. Specific risks are identified and strategies to avoid them are evaluated. The prognosis and management of pregnant women who have undergone bariatric surgery is also discussed, and practical guidelines for obstetric management of these patients are presented.

Supine hypotensive syndrome of pregnancy: A review of current knowledge

Since the first description of supine hypotensive syndrome in the 1950s, its potentially detrimental effects on otherwise healthy women during late pregnancy have become a persistent challenge in obstetric practice. Establishing a 15° left lateral tilt during labour and caesarean section is a fundamental principle of obstetric care, universally adopted and upheld by current guidelines and recommendations. Reassessment of the original landmark studies in the light of current physiological and anatomical knowledge questions adherence to this standard in clinical practice. The modern practice of providing vasopressor support during caesarean delivery under neuraxial anaesthesia appears to negate any potential negative effects of a maternal full supine position. Recent MRI studies provide evidence as to the cause of supine hypotension and the physiological effects of different maternal positions at term. This review highlights current data on the acute supine hypotensive syndrome in contrast to traditional knowledge and established practice.

Ultrasound evaluation of inferior vena cava compression in tilted and supine term parturients

PURPOSE

Hypotension is common following spinal anesthesia (SA) during elective Cesarean delivery (CD). Although common practice is to alleviate inferior vena cava (IVC) compression, limited evidence supports a 15° tilt for CD. We measured collapsibility of the IVC in supine and 15° left lateral tilt positions with ultrasound before and after SA and phenylephrine infusion in term parturients.

METHODS

Twenty term parturients scheduled for CD were recruited for this prospective study. Ultrasound measurements of the IVC were taken 1) supine before SA, 2) tilted 15° before SA, 3) supine after SA, and 4) tilted 15° after SA. A phenylephrine infusion was begun after injection of SA. The primary outcome was to evaluate the impact of position on the IVC collapsibility index (IVCCI): a measure of the difference between the maximum and minimum IVC diameter with respiration.

RESULTS

The mean (standard deviation) IVCCI (%) before SA was higher in the supine 19.5 (8.0) than in the tilted 15.0 (6.4) position (mean difference, 4.5; 95% confidence interval [CI], 0.1 to 8.9; P = 0.04). After SA, there was no significant difference between IVCCI (%) in the supine 17.8 (8.3) and tilted 14.2 (6.9) position (mean difference, 3.5; 95% CI, -0.9 to 7.9; P = 0.13). There was no correlation between the pre-spinal IVVCI measurements and the quantity of phenylephrine used during the surgery.

CONCLUSION

The IVCCI was lower in the 15° tilt position than in the supine position, but not after SA with a phenylephrine infusion. Ultrasound imaging can help identify IVC compression.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT03410199); registered 18 January 2018.

Effect of Different Positions During Surgical Preparation With Combined Spinal-Epidural Anesthesia for Elective Cesarean Delivery: A Randomized Controlled Trial

BACKGROUND

The intraoperative 15° left-tilt position during cesarean delivery has more recently been questioned regarding its effect on fetal acid-base balance and is a frequent source of complaints by surgeons. We hypothesized that a 30° left-tilt position during surgical preparation could improve the acid-base balance of the fetus compared with the 15° left-tilt or supine position during surgical preparation.

METHODS

Women undergoing elective cesarean delivery under combined spinal epidural anesthesia were randomized to a supine position, 15° left-lateral tilt position or 30° left-lateral tilt position; the position was changed to supine before the incision. Anesthetic management was standardized and included fluid loading with 10 mL/kg of normal saline followed by colloid loading. Hypotension (systolic blood pressure [SBP] reduction >20% baseline value or SBP <90 mm Hg) was treated with boluses of phenylephrine or ephedrine according to maternal heart rate. The primary outcome was umbilical arterial blood pH and the secondary outcomes included maternal SBP within 15 minutes after induction of anesthesia, the amount of vasoactive drug administered before end of the surgery, and the incidence of hypotension during cesarean delivery.

RESULTS

Seventy-five patients were included. After testing by analysis of variance, there was no significant difference in the umbilical arterial pH among the 3 groups (supine group: 7.31 ± 0.03 vs 15° group: 7.30 ± 0.04 vs 30° group: 7.31 ± 0.02, P = .28). The 30° group required significantly less phenylephrine (P = .007) and ephedrine (P = .005) before the end of surgery than the supine group; however, the only benefit observed in the 15° group was that the mean SBP at 3 minutes after spinal injection was significantly improved compared with the supine group.

CONCLUSIONS

Compared with the supine position, the 30° left-tilt position during surgical preparation did not significantly improve the fetal acid-base status, but it significantly reduced the use of phenylephrine and ephedrine and reduced the incidence of hypotension; however, these benefits were not observed in the 15° left-tilt group.

Observation of hemodynamic parameters using a non-invasive cardiac output monitor system to identify predictive indicators for post-spinal anesthesia hypotension in parturients undergoing cesarean section

The administration of high-level spinal anesthesia for cesarean section may lead to significant hemodynamic changes. Bioreactance-based non-invasive cardiac output monitoring (NICOM^™) provides an accurate monitoring system for parturients under spinal anesthesia. The present study hypothesized that baseline hemodynamic parameters obtained via the NICOM^™ system could serve as predictive indicators for post-spinal anesthesia hypotension. Therefore, 80 full-term parturients with singleton pregnancies who underwent scheduled cesarean section were enrolled and allocated to either a supine position group or a 15˚ left tilt group. All parturients received standard pre-hydration with 750 ml of 0.9% saline. Baseline cardiac output index (CI), total peripheral resistance index (TPRI) and stroke volume (SV) were recorded using the NICOM^™ system. Subsequently, spinal anesthesia with 2.4 ml of 0.5% hyperbaric bupivacaine, 10 µg of fentanyl and 0.2 mg of morphine was administered. Receiver operating characteristic (ROC) curves and multivariate logistic regression were used to analyze the data. A total of 40 parturients (51.9%) developed hypotension. The areas under the ROC curves were 0.666, 0.594 and 0.622 for the CI, TPRI and SV, respectively. The optimal cut-off value of the CI in predicting hypotension was 3.68 l/min/m² (ROC, sensitivity=85.0%, specificity=48.6%). Furthermore, CI was considered as an independent factor for post-spinal anesthesia hypotension. In conclusion, the baseline CI obtained via the bioreactance-based NICOM^™ system may serve as a predictor of post-spinal anesthesia hypotension in parturients regardless of patient position.

The optimum management of nausea and vomiting during and after cesarean delivery

Intraoperative and postoperative nausea and vomiting (IONV and PONV) afflict up to 80% of parturients undergoing cesarean delivery with neuraxial anesthesia. Preventing nausea and emesis is a top priority for women undergoing cesarean delivery and is included in the quality of recovery measures and enhanced recovery after cesarean delivery protocols. The majority of known perioperative emetic triggers can be avoided or mitigated by optimizing anesthetic and surgical management. IONV may arise from spinal anesthesia-induced hypotension, intraoperative pain, and medications such as uterotonics and antibiotics. Furthermore, uterine exteriorization and peritoneal irrigation increase IONV risk. Conversely, preventing PONV mainly focuses on optimizing analgesia through an opioid-sparing, multimodal strategy. In addition, combination prophylactic antiemetic therapy should be instituted in this high-risk population to further reduce the risk of IONV and PONV.

Hemodynamic profiles with and without left uterine displacement: A randomized study in term pregnancies receiving subarachnoid blockade for cesarean delivery

STUDY OBJECTIVE

The aim of this study was to evaluate the effect of left uterine displacement (LUD) on maternal hemodynamic measures following subarachnoid blockade (SAB) for cesarean delivery (CD). The primary outcome was cardiac output (CO) differences between the LUD and non-LUD groups pre-delivery.

DESIGN

Prospective, randomized, controlled study.

SETTING

Obstetric operating room.

MATERIALS AND METHODS

We studied hemodynamic profiles in sixty healthy women with term pregnancies who underwent elective CD with SAB. Hemodynamics were measured using a non-invasive CO monitor, the Nexfin™. All women received a crystalloid 10 mL/kg preload, and hypotension was treated with ephedrine boluses.

INTERVENTIONS

Sixty women with term pregnancies were randomized into two groups: LUD group (received 15-30° LUD after SAB, n = 30) and non-LUD group (no LUD after SAB, n = 30).

MEASUREMENTS

Patient's hemodynamic variables including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), CO, systemic vascular resistance (SVR), and left ventricular contractility index (dP/dT) were measured continuously from pre-SAB until end of surgery.

MAIN RESULTS

In pre-delivery phase at 5 min after spinal anesthesia, the LUD group had significantly higher CO (7.20 ± 1.78 [95%CI 6.53-7.87] vs. 6.23 ± 1.44 L/min [95% CI 5.69-6.77]; p = 0.016) and higher dP/dT (784 ± 313 vs. 604 ± 241 mmHg/s; p = 0.020) than the non-LUD group. The LUD group had a lower incidence of maternal systolic hypotension at 5-min post-SAB (16.7% vs. 53.3% in non-LUD group, p = 0.003).

CONCLUSIONS

The study demonstrates modest hemodynamic advantages (higher CO, less hypotension, higher dP/dT) with pre-delivery LUD. The results support maternal hemodynamic benefits of LUD until delivery in women with term pregnancies undergoing CD with SAB.

Transient Tachypnea of Newborns Is Associated With Maternal Spinal Hypotension During Elective Cesarean Delivery: A Retrospective Cohort Study

BACKGROUND

The risk for transient tachypnea of newborns, a common cause of respiratory distress in the neonatal period, is 2- to 6-fold higher during elective cesarean delivery compared to vaginal delivery. Here, we evaluated the association between transient tachypnea of newborns and the degree and duration of predelivery maternal hypotension during spinal anesthesia for elective cesarean delivery.

METHODS

Demographic data, details of anesthetic management, blood pressure measurements, and vasopressor requirement preceding delivery were compared between transient tachypnea newborns (n = 30) and healthy neonates (n = 151) with normal respiratory function born via elective cesarean delivery between July 2015 and February 2016. The degree and duration of hypotension were assessed using area under the curve for systolic blood pressure (SBP) ≤90 mm Hg and area under the curve for mean arterial pressure ≤65 mm Hg. After adjusting for confounders, multivariable logistic regression was used to evaluate the association between area under the curve for SBP and transient tachypnea of newborns.

RESULTS

The median area under the curve for SBP was higher in cases of transient tachypnea of newborns (0.94; interquartile range, 0-28.7 mm Hg*min) compared to healthy controls (0; interquartile range, 0-3.30 mm Hg*min; P = .001). Similarly, median area under the curve for mean arterial pressure was also higher in cases of transient tachypnea of newborns (0; interquartile range, 0-18.6 mm Hg*min) compared to controls (0; interquartile range, 0-1.1 mm Hg*min; P = .01). Mothers of transient tachypnea newborns received significantly higher amounts of phenylephrine and ephedrine compared to controls (P = .001 and 0.01, respectively). Hence, the total vasopressor dose given to mothers in the transient tachypnea of newborn group was much higher than for the control group (P = .001). In the multivariable logistic regression, area under the curve for SBP was significantly associated with transient tachypnea of newborns (odds ratio, 1.02; 95% CI, 1.01-1.04, P = .005) after adjusting for gravidity and the type of anesthetic (spinal versus combined spinal epidural).

CONCLUSIONS

Our results suggest that the degree and duration of maternal SBP <90 mm Hg after neuraxial anesthesia during elective cesarean delivery are associated with transient tachypnea of newborns. Future prospective studies should further explore the effects of maternal hypotension, its prevention, and treatment for transient tachypnea of newborns.

Effects of Vasoactive Medications and Maternal Positioning During Cesarean Delivery on Maternal Hemodynamics and Neonatal Acid-Base Status

Maternal hemodynamics, positioning, and anesthesia technique for cesarean delivery influence neonatal acid-base balance; direct effects from drugs that cross the placenta also have an influence. Spinal anesthesia limits fetal exposure to depressant drugs and avoids maternal airway instrumentation, but is associated with hypotension. Hypotension may be prevented/treated with vasopressors and intravenous fluids. Current evidence supports phenylephrine as the first-line vasopressor. Fifteen degrees of lateral tilt during cesarean delivery has been advocated to relieve vena caval obstruction, but routine use may be unnecessary in healthy nonobese women having elective cesarean delivery if maternal blood pressure is maintained near baseline.

[Cardiorespiratory effects of perioperative positioning techniques]

The supine position is still the most frequently used type of positioning during surgical procedures. Positions other than the supine position lead to physiological alterations that have a relevant influence on the course of anesthesia and surgery. As a matter of principle, hemodynamic stability is at risk because venous blood is pooled in the lower positioned body parts. In addition, head down positions (Trendelenburg position) may lead to an impairment of respiratory function by reducing lung volumes as well as lung compliance. Upright positions (beach chair position) are characterized by a relative hypovolemia accompanied by a reduction of mean arterial pressure, cardiac output and stroke volume, whereas pulmonary functions remain unchanged. Some severe adverse events have been described in the literature (e.g. intraoperative apoplexy, postoperative blindness). The pathophysiological principles and effects of hemodynamic alterations as well as potential strategies to avoid complications are presented and discussed in this lead article. Head down positions, especially the Trendelenburg position, cause a relative (intrathoracic) hypervolemia and an increase in cardiac preload that is usually well-tolerated in patients without heart problems; however, the Trendelenburg position, especially if combined with a capnoperitoneum, significantly impairs pulmonary function, can have a negative effect on intracerebral pressure and may reduce blood flow of intra-abdominal organs. The pathophysiological intraoperative changes caused by Trendelenburg positioning are described and approaches suitable for risk reduction are discussed. The prone position and lateral decubitus position have little influence on the intraoperative homeostasis. Nevertheless, there is an ongoing discussion concerning the efficacy of a 15° left lateral position during caesarean section, which is also discussed in a separate section of this review.

Gynecologic cancers in pregnancy: guidelines based on a third international consensus meeting

We aimed to provide comprehensive protocols and promote effective management of pregnant women with gynecological cancers. New insights and more experience have been gained since the previous guidelines were published in 2014. Members of the International Network on Cancer, Infertility and Pregnancy (INCIP), in collaboration with other international experts, reviewed existing literature on their respective areas of expertise. Summaries were subsequently merged into a manuscript that served as a basis for discussion during the consensus meeting. Treatment of gynecological cancers during pregnancy is attainable if management is achieved by collaboration of a multidisciplinary team of health care providers. This allows further optimization of maternal treatment, while considering fetal development and providing psychological support and long-term follow-up of the infants. Nonionizing imaging procedures are preferred diagnostic procedures, but limited ionizing imaging methods can be allowed if indispensable for treatment plans. In contrast to other cancers, standard surgery for gynecological cancers often needs to be adapted according to cancer type and gestational age. Most standard regimens of chemotherapy can be administered after 14 weeks gestational age but are not recommended beyond 35 weeks. C-section is recommended for most cervical and vulvar cancers, whereas vaginal delivery is allowed in most ovarian cancers. Breast-feeding should be avoided with ongoing chemotherapeutic, endocrine or targeted treatment. More studies that focus on the long-term toxic effects of gynecologic cancer treatments are needed to provide a full understanding of their fetal impact. In particular, data on targeted therapies that are becoming standard of care in certain gynecological malignancies is still limited. Furthermore, more studies aimed at the definition of the exact prognosis of patients after antenatal cancer treatment are warranted. Participation in existing registries (www.cancerinpregnancy.org) and the creation of national tumor boards with multidisciplinary teams of care providers (supplementary Box S1, available at Annals of Oncology online) is encouraged.

Effect of Right-Lateral Versus Left-Lateral Tilt Position on Compression of the Inferior Vena Cava in Pregnant Women Determined by Magnetic Resonance Imaging

BACKGROUND

Despite the existing dogma that women undergoing cesarean delivery under spinal anesthesia should be positioned with a 15° left-lateral tilt, the patients were actually positioned in a right-lateral tilt position in several of the original studies. The superiority of right versus left positioning for optimal inferior vena cava volume is unknown. We used magnetic resonance imaging to compare the effects of right-lateral and left-lateral tilt positions on abdominal aortic and inferior vena cava volumes in pregnant women.

METHODS

Thirteen women with singleton pregnancies and gestational age 31-39 weeks underwent magnetic resonance imaging while in the supine position, and in the left-lateral (15° and 30°) and right-lateral tilt (15° and 30°) positions, which were maintained by placing a 1.5-m-long piece of polyethylene foam under either side of the body. Abdominal aorta and inferior vena cava volume were measured between the L1-L2 disk and L3-L4 disk levels using magnetic resonance images.

RESULTS

Aortic volume did not differ significantly among any of the positions examined. Mean inferior vena cava volume was significantly greater in the 30° left-lateral tilt position than in the 15° right-lateral tilt (10.7 ± 7.5 vs 5.9 ± 5.1 mL; mean difference, 4.8; 95% CI, 1.2-8.5; P = .002) and 30° right-lateral tilt (10.7 ± 7.5 vs 5.9 ± 2.5 mL; mean difference, 4.8; 95% CI, 1.2-8.4; P = .002) positions. Mean inferior vena cava volume in the 15° left-lateral tilt position did not differ significantly from that in the 15° right-lateral tilt (mean difference, 0.4; 95% CI, -3.2 to 4.0; P = 1.000) or 30° right-lateral tilt (mean difference, 0.4; 95% CI, -3.3 to 4.0; P = 1.000) positions. Mean inferior vena cava volume in the supine position only differed significantly from that in the 30° left-lateral tilt position (5.2 ± 3.8 vs 10.7 ± 7.5 mL; mean difference, 5.5; 95% CI, 1.8-9.1; P < .001). The greatest inferior vena cava volume was observed in the 30° left-lateral tilt position in 9 of 13 subjects (70%), and in the 30° right-lateral tilt in 3 subjects (23%).

CONCLUSIONS

The 30° left-lateral tilt position most consistently reduced inferior vena cava compression by the gravid uterus compared with the supine position. Mean inferior vena cava volume in pregnant women was not increased at either angle of the right-lateral tilt position compared with the 30° left-lateral tilt position. However, in a subset of patients, the 30° right-lateral tilt position achieved the optimal inferior vena cava volume. Further investigation to understand this variability is warranted.

Preventive intramuscular phenylephrine in elective cesarean section under spinal anesthesia: A randomized controlled trial

BACKGROUND

Phenylephrine is the first-line vasoactive drug in the cesarean section under spinal anesthesia. The rate of hypotension remains high after intravenous preventive use of phenylephrine. However, few studies have investigated the effect of preventive intramuscular phenylephrine via a longer period of usage on fetal and maternal outcomes.

METHODS

A total of 99 healthy parturients undergoing elective cesarean delivery were randomly allocated into three groups: M group (preventive intramuscular use of 5 mg phenylephrine), V group (preventive intravenous use of 100 μg phenylephrine), and P group (0.9% normal saline placebo). Rescue phenylephrine, ephedrine and atropine were used intraoperatively to adjust blood pressure and heart rate. The primary outcome was umbilical artery pH.

RESULTS

Significant differences in umbilical artery pH (M group: 7.32 ± 0.05 versus V group: 7.25 ± 0.04 versus P group: 7.21 ± 0.03, P < 0.05), fetal acidosis (M group: 3% [n = 33] versus V group: 15% [n = 33] versus P group: 30% [n = 33], P = 0.01) and maternal intraoperative hypotension (M group: 12% [33] versus V group: 39% [33] versus P group: 73% [33], P < 0.0001) were identified among the groups. Multiple linear regression analysis demonstrated that treating arms, neonatal birthweight and the interval from the end of anesthesia to baby delivery were associated with umbilical artery pH.

CONCLUSION

Compared with the preventive intravenous use of phenylephrine and placebo, preventive intramuscular phenylephrine exhibited a better neonatal acid-base status and more stable maternal hemodynamics in elective cesarean under spinal anesthesia.

Bezold-Jarisch reflex occurred in a pediatric patient with giant intra-abdominal teratoma during induction of anesthesia: A case report

RATIONALE

Bezold-Jarisch reflex (BJR) occurs when the cardioinhibitory receptors in the walls of ventricles are activated by various stimuli, with typical features of bradycardia, vasorelaxation, and hypotension. This reflex usually happens in parturient intrathecal anesthesia, as a result of decreased venous return by compression of inferior vena cava, but it is only rarely reported during general anesthesia.

PATIENT CONCERNS

Severe bradycardia and hypotension, indicating BJR, occurred during the induction of general anesthesia in a 3-month-old female child with giant intra-abdominal teratoma.

DIAGNOSES

A giant intra-abdominal teratoma was detected by computed tomography scanning. The decreased left ventricular ejection faction along with increased troponin I and N-terminal pro-B-type natriuretic peptide indicated a preoperative mild cardiac dysfunction. BJR was diagnosed on the basis of the severe bradycardia and hypotension observed during the induction of general anesthesia, INTERVENTIONS:: Atropine failed to increase heart rate. Cardiopulmonary resuscitation was initiated immediately and epinephrine was injected intravenously because of sudden circulatory collapse. Soon after the return of spontaneous circulation, a central venous line was placed and invasive blood pressure was monitored. Vital signs and homeostasis were kept stable during teratoma resection.

OUTCOMES

The child was extubated after emergence from anesthesia in the operating room. Eleven days later, she had recovered without complications and was discharged.

LESSONS

General anesthesia should be induced with great care in patients with giant intra-abdominal masses, and the patient should be kept in the left-lateral table tilt position before induction.