Maternal posture-physiology interactions in human pregnancy: a narrative review

There are several well-known medical conditions in which posture and gravity interact with natural history, including pregnancy. In this review, we provide a comprehensive overview of interactions between maternal posture and maternal physiology and pathophysiology at rest during pregnancy. We conducted a systematic literature search of the MEDLINE database and identified 644 studies from 1991 through 2021, inclusive, that met our inclusion criteria. We present a narrative review of the resulting literature and highlight discrepancies, research gaps, and potential clinical implications. We organize the results by organ system and, commencing with the neurological system, proceed in our synthesis generally in the craniocaudal direction, concluding with the skin. The circulatory system warranted our greatest and closest consideration-literature concerning the dynamic interplay between physiology (heart rate, stroke volume, cardiac output, blood pressure, and systemic vascular resistance), pathophysiology (e.g., hypertension in pregnancy), and postural changes provide an intricate and fascinating example of the importance of the subject of this review. Other organ systems discussed include respiratory, renal, genitourinary, gastrointestinal, abdominal, and endocrine. In addition to summarizing the existing literature on maternal posture-physiology interactions, we also point out gaps and opportunities for further research and clinical developments in this area. Overall, our review provides both insight into and relevance of maternal posture-physiology interactions vis à vis healthcare's mission to improve health and wellness during pregnancy and beyond.

Maternal rest improves growth in small-for-gestational-age fetuses (<10th percentile)

BACKGROUND

Optimal management of fetuses diagnosed as small for gestational age based on an estimated fetal weight of <10th percentile represents a major clinical problem. The standard approach is to increase fetal surveillance with serial biometry and antepartum testing to assess fetal well-being and timing of delivery. Observational studies have indicated that maternal rest in the left lateral position improves maternal cardiac output and uterine blood flow. However, maternal bed rest has not been recommended based on the results of a randomized clinical trial that showed that maternal rest does not improve fetal growth in small-for-gestational-age fetuses. This study was conducted to revisit this question.

OBJECTIVE

This study aimed to determine whether maternal bed rest was associated with an increase in the fetal biometric parameters that reflect growth after the diagnosis of a small-for-gestational-age fetus.

STUDY DESIGN

A retrospective study was conducted on fetuses who were diagnosed as small for gestational age because of an estimated fetal weight of <10th percentile for gestational age. The mothers were asked to rest in the left lateral recumbent position. Fetal biometry was performed 2 weeks after the diagnosis. All fetuses before entry into the study had a previous ultrasound that demonstrated an estimated fetal weight of >10th percentile. To assess the response to bed rest, the change in fetal biometric parameters (estimated fetal weight, head circumference, abdominal circumference, and femur length) after the recommendation of bed rest was computed for 2 periods: (1) before the diagnosis of a weight of <10th percentile vs at the time of diagnosis of a weight of <10th percentile and (2) at the time of diagnosis of a weight of <10th percentile vs 2 weeks after maternal bed rest. For repeated measures, proportions were compared using the McNemar test, and percentile values were compared using the Bonferroni Multiple Comparison Test. A P value of <.05 was considered significant. To describe changes in the estimated fetal weight without bed rest, 2 control groups in which the mothers were not placed on bed rest after the diagnosis of a small-for-gestational-age fetus were included.

RESULTS

A total of 265 fetuses were observed before and after maternal bed rest. The following were observed in this study: (1) after 2 weeks of maternal rest, 199 of 265 fetuses (75%) had a fetal weight of >10th percentile; (2) the median fetal weight percentile increased from 6.8 (interquartile range, 4.4-8.4) to 18.0 (interquartile range, 9.5-29.5) after 2 weeks of bed rest; (3) similar trends were noted for the head circumference, abdominal circumference, and femur length. In the groups of patients who were not asked to be on bed rest, a reassignment to a weight of >10th percentile at a follow-up examination only occurred in 7 of 37 patients (19%) in the Texas-Michigan group and 13 of 111 patients (12%) in the Colorado group compared with the bed rest group (199/265 [75%]) (P<.001).

CONCLUSION

Patients who were prescribed 2 weeks of bed rest after the diagnosis of a fetal weight of <10th percentile had an increase in weight of >10th percentile in 199 of 265 fetuses (75%). This increase in fetal weight was significantly higher than that in the 2 control groups in which bed rest was not prescribed. This observation suggests that bed rest improves fetal growth in a subset of patients.

Impact of maternal posture on fetal physiology in human pregnancy: a narrative review

In numerous medical conditions, including pregnancy, gravity and posture interact to impact physiology and pathophysiology. Recent investigations, for example, pertaining to maternal sleeping posture during the third trimester and possible impact on fetal growth and stillbirth risk highlight the importance and potential clinical implications of the subject. In this review, we provide an extensive discussion of the impact of maternal posture on fetal physiology from conception to the postpartum period in human pregnancy. We conducted a systematic literature search of the MEDLINE database and identified 242 studies from 1991 through 2021, inclusive, that met our inclusion criteria. Herein, we provide a synthesis of the resulting literature. In the first section of the review, we group the results by the impact of maternal posture at rest on the cervix, uterus, placenta, umbilical cord, amniotic fluid, and fetus. In the second section of the review, we address the impact on fetal-related outcomes of maternal posture during various maternal activities (e.g., sleep, work, exercise), medical procedures (e.g., fertility, imaging, surgery), and labor and birth. We present the published literature, highlight gaps and discrepancies, and suggest future research opportunities and clinical practice changes. In sum, we anticipate that this review will shed light on the impact of maternal posture on fetal physiology in a manner that lends utility to researchers and clinicians who are working to improve maternal, fetal, and child health.

Risk factors of more severe hypotension after spinal anesthesia for cesarean section

BACKGROUND

The aim of this study was to examine the risk factors associated with the use of vasopressors to prevent hypotension that occurs after spinal anesthesia during cesarean section. Although the prophylactic use of vasopressors is already suggested as routine care in many parts of the world, the occurrence of spinal anesthesia-induced hypotension (SAIH) is still common in parturients.

METHODS

This retrospective study included parturients receiving elective cesarean deliveries under spinal anesthesia from April 2016 to March 2020. Risk factors related to ephedrine dosage were analyzed using a hurdle model, and risk factors related to SAIH were further analyzed with logistic regression.

RESULTS

Five risk factors, namely maternal body mass index (BMI, p < 0.001), baseline systolic blood pressure (SBP, p < 0.001), baseline heart rate (HR, p = 0.047), multiparity ( p = 0.003), and large fetal weight ( p = 0.005) were significantly associated with the requirement for ephedrine. Furthermore, a higher ephedrine dosage was significantly associated with maternal BMI ( p < 0.001), baseline SBP ( p < 0.001), baseline HR ( p < 0.001), multiparity ( p = 0.027), large fetal weight ( p = 0.030), maternal age ( p = 0.009), and twin pregnancies ( p < 0.001). Logistic regression analysis also showed that the same five risk factors-maternal BMI ( p = 0.030), baseline SBP ( p < 0.001), baseline HR ( p < 0.001), multiparity ( p < 0.001), and large fetal weight ( p < 0.001)-were significantly associated with SAIH, even in cases where vasopressors were administered.

CONCLUSION

These findings can be useful for clinicians when deciding the dose of prophylactic ephedrine or phenylephrine to prevent SAIH.

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.

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.

Awake craniotomy during pregnancy: A systematic review of the published literature

Neurosurgical pathologies in pregnancy pose significant complications for the patient and fetus, and physiological stressors during anesthesia and surgery may lead to maternal and fetal complications. Awake craniotomy (AC) can preserve neurological functions while reducing exposure to anesthetic medications. We reviewed the literature investigating AC during pregnancy. PubMed, Scopus, and Web of Science databases were searched from the inception to February 7th, 2023, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Studies in English investigating AC in pregnant patients were included in the final analysis. Nine studies composed of nine pregnant patients and ten fetuses (one twin-gestating patient) were included. Glioma was the most common pathology reported in six (66.7%) patients. The frontal lobe was the most involved region (4 cases, 44.4%), followed by the frontoparietal region (2 cases, 22.2%). The awake-awake-awake approach was the most common protocol in seven (77.8%) studies. The shortest operation time was two hours, whereas the longest one was eight hours and 29 min. The mean gestational age at diagnosis was 13.6 ± 6.5 (2-22) and 19.6 ± 6.9 (9-30) weeks at craniotomy. Seven (77.8%) studies employed intraoperative fetal heart rate monitoring. None of the AC procedures was converted to general anesthesia. Ten healthy babies were delivered from patients who underwent AC. In experienced hands, AC for resection of cranial lesions of eloquent areas in pregnant patients is safe and feasible and does not alter the pregnancy outcome.

The effect of prone positioning on maternal haemodynamics and fetal wellbeing in the third trimester-A primary cohort study with a scoping review

INTRODUCTION

Supine sleep position is associated with stillbirth, likely secondary to inferior vena cava compression, and a reduction in cardiac output (CO) and uteroplacental perfusion. Evidence for the effects of prone position in pregnancy is less clear. This study aimed to determine the effect maternal prone position on maternal haemodynamics and fetal heart rate, compared with left lateral position.

METHODS

Twenty-one women >28 weeks' gestation underwent non-invasive CO monitoring (Cheetah) every 5 minutes and continuous fetal heart rate monitoring (MONICA) in left lateral (20 minutes), prone (30 minutes), followed by left lateral (20 minutes). Anxiety and comfort were assessed by questionnaires. Regression analyses (adjusted for time) compared variables between positions. The information derived from the primary study was used in an existing mathematical model of maternal circulation in pregnancy, to determine whether occlusion of the inferior vena cava could account for the observed effects. In addition, a scoping review was performed to identify reported clinical, haemodynamic and fetal effects of maternal prone position; studies were included if they reported clinical outcomes or effects or maternal prone position in pregnancy. Study records were grouped by publication type for ease of data synthesis and critical analysis. Meta-analysis was performed where there were sufficient studies.

RESULTS

Maternal blood pressure (BP) and total vascular resistance (TVR) were increased in prone (sBP 109 vs 104 mmHg, p = 0.03; dBP 74 vs 67 mmHg, p = 0.003; TVR 1302 vs 1075 dyne.s-1cm-5, p = 0.03). CO was reduced in prone (5.7 vs 7.1 mL/minute, p = 0.003). Fetal heart rate, variability and decelerations were unaltered. However, fetal accelerations were less common in prone position (86% vs 95%, p = 0.03). Anxiety was reduced after the procedure, compared to beforehand (p = 0.002), despite a marginal decline in comfort (p = 0.04).The model predicted that if occlusion of the inferior vena cava occurred, the sBP, dBP and CO would generally decrease. However, the TVR remained relatively consistent, which implies that the MAP and CO decrease at a similar rate when occlusion occurs. The scoping review found that maternal and fetal outcomes from 47 included case reports of prone positioning during pregnancy were generally favourable. Meta-analysis of three prospective studies investigating maternal haemodynamic effects of prone position found an increase in sBP and maternal heart rate, but no effect on respiratory rate, oxygen saturation or baseline fetal heart rate (though there was significant heterogeneity between studies).

CONCLUSION

Prone position was associated with a reduction in CO but an uncertain effect on fetal wellbeing. The decline in CO may be due to caval compression, as supported by the computational model. Further work is needed to optimise the safety of prone positioning in pregnancy.

TRIAL REGISTRATION

This trial was registered at clinicaltrials.gov (NCT04586283).

Medical Emergencies in the Pregnant Patient

This review article provides a comprehensive overview of common medical emergencies that can occur in pregnant patients. We summarize the key diagnostic and management steps for each emergency to assist health care professionals in identifying and treating these potentially life-threatening conditions. The medical emergencies discussed in this article include postpartum hemorrhage; hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome; acute fatty liver of pregnancy; amniotic fluid embolism; pulmonary embolism; acute respiratory distress syndrome; and shock. Each condition is described in detail, with a focus on the clinical presentation, diagnostic workup, and treatment options. The information presented in this review article is based on current best practices and guidelines from leading medical organizations. We hope this article will serve as a valuable resource for health care professionals who care for pregnant patients and help improve outcomes for these patients in emergency situations.

Preanesthetic ultrasonography assessment of inferior vena cava diameter in the supine position, left lateral tilt position, and with the left uterine displacement maneuver in full-term pregnant women: A randomized cross-over design study

Preanesthetic ultrasonography assessment of inferior vena cava diameter (IVCD) in the supine position (SP), left lateral tilt position (LLT), and with the left uterine displacement maneuver (LUD) in full-term pregnant women: a randomized cross-over design study.

AIM

We pre-anesthetically measured IVCD using ultrasonography in the SP, LLT, and the LUD in full-term pregnant women, using a cross-over design, to evaluate the effectiveness of LLT and LUD on increasing IVCD, and the presence of inter-individual differences among patients in the effect of posture on IVCD.

METHODS

Twenty-two parturients scheduled for elective cesarean section under spinal anesthesia were recruited. All patients were sequentially placed in the SP, LLT, and with LUD before spinal anesthesia induction. Indices of IVCD, measured by subxiphoid ultrasonography, including maximum IVCD (IVCDmax), minimum IVCD (IVCDmin), and collapsibility index (CI) were recorded in each of the postures. Mean or median values of all measurements were compared among the postures.

RESULTS

The mean values of IVCDmax observed with both LLT and LUD were significantly larger than those in the SP, respectively (SP vs. LLT: p < 0.05, SP vs. LUD: p < 0.01), although there were no significant differences between IVCDmax with LLT and LUD. There were no significant differences in IVCDmin and CI between any of the postures. IVCDmax was highest with LUD in 11 patients (55%), in the LLT in seven patients (35%) and in the SP in two patients (10%).

CONCLUSIONS

LLT and LUD might be equally effective in enlarging the narrowed IVCD as compared to SP. However, both LLT and LUD might not necessarily be appropriate treatments to relieve IVC compression in some cases.

Effect of different position on inferior vena cava dimensions and its influence on hemodynamics during cesarean section under combined spinal-epidural anesthesia: A randomized controlled trial

OBJECTIVE

The purpose of our study was to investigate the effect of the 15° left operating table tilt on the inferior vena cava (IVC) and the hemodynamics of full-term pregnant women, and to evaluate the efficacy of inferior vena cava collapse index (IVCCI) in predicting hypotension.

METHODS

All parturients planning to perform cesarean section (CS) were randomly divided into supine group and 15° group. Their parameters of IVC were measured by ultrasound and then calculated the IVCCI. Systolic blood pressure (SBP), mean arterial pressure (MAP), and heart rate (HR) in two positions were recorded from baseline to fetal delivery.

RESULTS

The IVCCI in the 15° group was significantly lower when compared with that in the supine group (20.40 [18.84-21.60] vs. 21.82 [20.16-22.79] %, p = 0.012). The incidence of hypotension was observed statistically lower in the 15° group than the supine group (27.5% vs. 50%, p = 0.039). Best cut-off value was 21.69% and area under the receiver operating characteristic (ROC) curve of IVCCI in supine position to predict hypotension was 0.93. Best cut-off value was 21.78% and area under the ROC curve of IVCCI in supine position to predict hypotension was 0.80.

CONCLUSIONS

The 15° left operating table tilt can relieve the extent of compression of IVC and reduce the incidence of hypotension. IVCCI can predict the occurrence of hypotension.

Obstetric Disorders and Critical Illness

In this article, we discuss some of the more common obstetric-related conditions that can lead to critical illness and require management in an ICU. These include the hypertensive disorders of pregnancy, postpartum hemorrhage, hemolysis, elevated liver enzymes, and low platelet syndrome, acute fatty liver of pregnancy, amniotic fluid embolism, and peripartum cardiomyopathy. We also discuss pulmonary embolism and Covid-19. Despite not being specific to obstetric patients, pulmonary embolism is a common, life-threatening diagnosis in pregnancy with particular risks and management aspects. Covid-19 does not seem to occur with higher frequency in pregnant women, but it leads to higher rates of ICU admissions and mechanical ventilation in pregnant women than in their nonpregnant peers. Its prevalence during our current global pandemic makes it important to discuss in this article. We provide a basis for critical care physicians to be engaged in informed conversations and management in a multidisciplinary manner with other relevant providers in the care of critically ill pregnant and postpartum women.

Non-invasive monitoring of blood oxygenation in human placentas via concurrent diffuse optical spectroscopy and ultrasound imaging

Direct assessment of blood oxygenation in the human placenta can provide information about placental function. However, the monitoring of placental oxygenation involves invasive sampling or imaging techniques that are poorly suited for bedside use. Here we show that placental oxygen haemodynamics can be non-invasively probed in real time and up to 4.2 cm below the body surface via concurrent frequency-domain diffuse optical spectroscopy and ultrasound imaging. We developed a multimodal instrument to facilitate the assessment of the properties of the anterior placenta by leveraging image-reconstruction algorithms that integrate ultrasound information about the morphology of tissue layers with optical information on haemodynamics. In a pilot investigation involving placentas with normal function (15 women) or abnormal function (9 women) from pregnancies in the third trimester, we found no significant differences in baseline haemoglobin properties, but statistically significant differences in the haemodynamic responses to maternal hyperoxia. Our findings suggest that the non-invasive monitoring of placental oxygenation may aid the early detection of placenta-related adverse pregnancy outcomes and maternal vascular malperfusion.

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 .

Effects of Performing Applied Muscle Tension during Recovery after Phlebotomy in Young, First-Time Donors: A Pilot Study

Vasovagal reaction (VVR) compromises donor safety and reduces the subsequent return rates. Performing applied muscle tension (AMT) during phlebotomy may reduce the incidence of VVR. However, the effectiveness of performing AMT after phlebotomy to reduce delayed VVR remains unclear. With ethics approval, 12 young, first-time donors (YFTD) were recruited to study the effects on stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) while performing AMT from needle insertion to end of recovery. Measurements from 12 matched control YFTD were used for comparison. Pre-donation anxiety and VVR severity were assessed. Compared to controls, donors who performed AMT had higher SV (Control: 57 mL vs. AMT: 69 mL, p = 0.045), higher CO (Control: 3.7 L·min⁻¹ vs. AMT: 5.2 L·min⁻¹, p = 0.006) and lower SVR (Control: 1962 dyn·s·cm⁻⁵ vs. AMT: 1569 dyn·s·cm⁻⁵, p = 0.032) during mid-phlebotomy. During recovery, the AMT group retained higher SV, higher CO and lower SVR than the control, but not reaching statistical significance. Practicing AMT during recovery resulted in sustained haemodynamic improvements beyond the donation period, despite the reduction in delayed VVR was insignificant compared to the control group. A larger sample size is needed to validate the effectiveness of performing AMT after donation to mitigate delayed VVR.

Trauma in Pregnancy

One of the most common causes of obstetric morbidity and mortality is trauma in pregnancy. Several maternal physiological changes during pregnancy have a significant impact on the mechanism, presentation, and management of trauma in this population. It is crucial for health providers dealing with trauma to know and understand these differences between pregnant and nonpregnant patients. The obstetric trauma patient requires a multidisciplinary approach, including obstetrics, maternal fetal medicine, anesthesiology, surgery, and intensive care teams. The aim of this article is to review the most updated information on trauma during pregnancy.

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.

Adnexal Masses in Pregnancy

Importance

Adnexal masses are identified in approximately 0.05% to 2.4% of pregnancies, and more recent data note a higher incidence due to widespread use of antenatal ultrasound. Whereas most adnexal masses are benign, approximately 1% to 6% are malignant. Proper diagnosis and management of adnexal masses in pregnancy are an important skill for obstetricians.

Objective

The aim of this study was to review imaging modalities for evaluating adnexal masses in pregnancy and imaging characteristics that differentiate benign and malignant masses, examine various types of adnexal masses, and understand complications of and explore management options for adnexal masses in pregnancy.

Evidence Acquisition

This was a literature review using primarily PubMed and Google Scholar.

Results

Ultrasound can distinguish between simple-appearing benign ovarian cysts and masses with more complex features that can be associated with malignancy. Radiologic information can help guide physicians toward recommending conservative management with observation or surgical removal during pregnancy to facilitate diagnosis and treatment. The risks of expectant management of an adnexal mass during pregnancy include rupture, torsion, need for emergent surgery, labor obstruction, and progression of malignancy. Historically, surgical removal was performed more routinely to avoid such complications in pregnancy; however, increasing knowledge has directed management toward conservative measures for benign masses. Surgical removal of adnexal masses is increasingly performed via minimally invasive techniques including laparoscopy and robotic surgery due to a decreased risk of surgical complications compared with laparotomy.

Conclusions and Relevance

Adnexal masses are increasingly identified in pregnancy because of the use of antenatal ultrasound. Clear and specific guidelines exist to help differentiate between benign and malignant masses. This is important for management as benign masses can usually be conservatively managed, whereas malignant masses require excision for diagnosis and treatment. A multidisciplinary approach, including referral to gynecologic oncology, should be used for masses with complex features associated with malignancy. Proper diagnosis and management of adnexal masses in pregnancy are an important skill for obstetricians.

Role of Critical Care Units in the management of obstetric patients (Review)

Pregnancy is considered a natural process for the majority of women. However, a limited proportion of pregnancies and deliveries can present with a broad variety of complications that may require admission to a Critical Care Unit (CCU). In the present review, the indications of admission of obstetrical and postpartum patients to CCUs were critically evaluated with a particular focus on the management of their complications. The management of critically ill obstetric patients remains challenging due to the physiological changes that occur during pregnancy, pregnancy-related diseases and the need to carefully consider the well-being of the fetus before any intervention can be recommended/performed. Indications for admission to CCUs include both obstetric and non-obstetric conditions that may require continuous monitoring and further interventions. Hypertensive disorders of pregnancy and mass hemorrhage are amongst the most common causes of admission to CCUs in pregnant and postpartum women. The establishment of a diagnostic and care algorithm based on the contribution of a multidisciplinary team is of critical importance to aid in the determination of which patients will require intensive care, and to assist in deciding what type of critical care each critically ill patients receives.

Cardiac Responses to Submaximal Isometric Contraction and Aerobic Exercise in Healthy Pregnancy

PURPOSE

The increased physiological demand of pregnancy results in the profound adaptation of the maternal cardiovascular system, reflected by greater resting cardiac output and left ventricular (LV) deformation. Whether the increased resting demand alters acute cardiac responses to exercise in healthy pregnant women is not well understood.

METHODS

Healthy nonpregnant (n = 18), pregnant (n = 14, 22-26 wk gestation), and postpartum women (n = 13, 12-16 wk postdelivery) underwent assessments of cardiac function and LV mechanics at rest, during a sustained isometric forearm contraction (30% maximum), and during low-intensity (LOW) and moderate-intensity (MOD) dynamic cycling exercise (25% and 50% peak power output). Significant differences (α = 0.05) were determined using ANCOVA and general linear model (resting value included as covariate).

RESULTS

When accounting for higher resting cardiac output in pregnant women, pregnant women had greater cardiac output during isometric contraction (2.0 ± 0.3 L·min-1·m-1.83; nonpregnant, 1.3 ± 0.2 L·min-1·m-1.83; postpartum, 1.5 ± 0.5 L·min-1·m-1.83; P = 0.02) but similar values during dynamic cycling exercise (pregnant, LOW = 2.8 ± 0.4 L·min-1·m-1.83, MOD = 3.4 ± 0.7 L·min-1·m-1.83; nonpregnant, LOW = 2.4 ± 0.3 L·min-1·m-1.83, MOD = 3.0 ± 0.3 L·min-1·m-1.83; postpartum, LOW = 2.3 ± 0.4 L·min-1·m-1.83, MOD = 3.0 ± 0.5 L·min-1·m-1.83; P = 0.96). Basal circumferential strain was higher in pregnant women at rest, during the sustained isometric forearm contraction (-23.5% ± 1.2%; nonpregnant, -14.6% ± 1.4%; P = 0.001), and during dynamic cycling exercise (LOW = -27.0% ± 4.9%, MOD = -27.4% ± 4.6%; nonpregnant, LOW = -15.8% ± 4.5%, MOD = -15.2% ± 6.7%; P = 0.012); however, other parameters of LV mechanics were not different between groups.

CONCLUSION

The results support that the maternal heart can appropriately respond to additional cardiac demand and altered loading experienced during acute isometric and dynamic exercise, although subtle differences in responses to these challenges were observed. In addition, the LV mechanics that underpin global cardiac function are greater in pregnant women during exercise, leading to the speculation that the hormonal milieu of pregnancy influences regional deformation.

[Principles of intensive medical care in pregnant patients]

As the incidence of diseases during pregnancy or in the puerperium necessitating intensive medical care is very low, intensive care physicians are faced with a multitude of unfamiliar challenges in the treatment of this patient collective. The physiological and pathophysiological alterations during pregnancy induce some specific features with respect to the intensive medical treatment of pregnant or postpartum patients. Therefore, the first article in this CME series summarizes the most important principles and current recommendations on the care of pregnant or postpartum patients who need intensive medical treatment, always under consideration of the well-being of mother and child. The second article describes the diagnostics and treatment of special selected pathologies.

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

Background

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

Methods

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

Results

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

Conclusions

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

Trial registration

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

The effect of body position on maternal cardiovascular function during sleep and wakefulness in late pregnancy

INTRODUCTION

An association between the increased risk of late stillbirth and the maternal supine sleeping position has been recently established. The risk of stillbirth following supine sleep has been suspected to occur as a result of aortocaval compression by the gravid uterus. A number of studies conducted during wakefulness have reported compromised cardiovascular function during supine rest, as demonstrated by reductions in cardiac output, blood pressure and utero-placental blood flow. It remains unclear whether similar effects are also present during sleep, due to the presence of key sleep-specific changes in cardiovascular function.

OBJECTIVE

To investigate the changes in maternal cardiovascular function between the supine and left-lateral positions during wakefulness and non-rapid eye movement (NREM) sleep in late pregnancy.

METHODS

Twenty-nine women with a singleton pregnancy between 24.7 and 36.7 weeks' gestation participated in a single overnight sleep study. Physiological measures (blood pressure, heart rate, heart rate variability - HRV, and pulse arrival time - PAT) were measured and recorded throughout the night using standard polysomnography equipment and the Portapres Model-2 device. As the present study evaluated cardiovascular changes during natural rest and sleep in pregnancy, participants were not given explicit instructions on which position to adopt. Body position was continuously recorded using a position monitor and verified with video recording.

RESULTS

No changes in systolic, diastolic or mean arterial blood pressure were observed between the left-lateral and supine positions during wakefulness or sleep. However, heart rate was significantly higher in the supine position compared to the left during wakefulness (p= .03), with a similar trend present during sleep (p= .11). A significantly shorter PAT was measured in the supine position (compared to the left) during wakefulness (p= .01) and sleep (p= .01). No change in HRV measures was observed between the left and supine positions in either state.

CONCLUSION

Blood pressure did not appear to differ significantly between the left-lateral and supine positions during wakefulness and sleep. The lack of blood pressure differences may reflect elevated sympathetic activity during rest and sleep in the supine position (compared to the left), suggesting that some degree of compensation for aortocaval compression may still be possible during sleep.

Techniques for preventing hypotension during spinal anaesthesia for caesarean section

BACKGROUND

Maternal hypotension is the most frequent complication of spinal anaesthesia for caesarean section. It can be associated with nausea or vomiting and may pose serious risks to the mother (unconsciousness, pulmonary aspiration) and baby (hypoxia, acidosis, neurological injury).

OBJECTIVES

To assess the effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (9 August 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials, including full texts and abstracts, comparing interventions to prevent hypotension with placebo or alternative treatment in women having spinal anaesthesia for caesarean section. We excluded studies if hypotension was not an outcome measure.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data from eligible studies. We report 'Summary of findings' tables using GRADE.

MAIN RESULTS

We included 125 studies involving 9469 women. Interventions were to prevent maternal hypotension following spinal anaesthesia only, and we excluded any interventions considered active treatment. All the included studies reported the review's primary outcome. Across 49 comparisons, we identified three intervention groups: intravenous fluids, pharmacological interventions, and physical interventions. Authors reported no serious adverse effects with any of the interventions investigated. Most trials reported hypotension requiring intervention and Apgar score of less than 8 at five minutes as the only outcomes. None of the trials included in the comparisons we describe reported admission to neonatal intensive care unit. Crystalloid versus control (no fluids) Fewer women experienced hypotension in the crystalloid group compared with no fluids (average risk ratio (RR) 0.84, 95% confidence interval (CI) 0.72 to 0.98; 370 women; 5 studies; low-quality evidence). There was no clear difference between groups in numbers of women with nausea and vomiting (average RR 0.19, 95% CI 0.01 to 3.91; 1 study; 69 women; very low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (60 babies, low-quality evidence). Colloid versus crystalloid Fewer women experienced hypotension in the colloid group compared with the crystalloid group (average RR 0.69, 95% CI 0.58 to 0.81; 2009 women; 27 studies; very low-quality evidence). There were no clear differences between groups for maternal hypertension requiring intervention (average RR 0.64, 95% CI 0.09 to 4.46, 3 studies, 327 women; very low-quality evidence), maternal bradycardia requiring intervention (average RR 0.98, 95% CI 0.54 to 1.78, 5 studies, 413 women; very low-quality evidence), nausea and/or vomiting (average RR 0.89, 95% CI 0.66 to 1.19, 14 studies, 1058 women, I² = 29%; very low-quality evidence), neonatal acidosis (average RR 0.83, 95% CI 0.15 to 4.52, 6 studies, 678 babies; very low-quality evidence), or Apgar score of less than 8 at five minutes (average RR 0.24, 95% CI 0.03 to 2.05, 10 studies, 730 babies; very low-quality evidence). Ephedrine versus phenylephrine There were no clear differences between ephedrine and phenylephrine groups for preventing maternal hypotension (average RR 0.92, 95% CI 0.71 to 1.18; 401 women; 8 studies; very low-quality evidence) or hypertension (average RR 1.72, 95% CI 0.71 to 4.16, 2 studies, 118 women, low-quality evidence). Rates of bradycardia were lower in the ephedrine group (average RR 0.37, 95% CI 0.21 to 0.64, 5 studies, 304 women, low-quality evidence). There was no clear difference in the number of women with nausea and/or vomiting (average RR 0.76, 95% CI 0.39 to 1.49, 4 studies, 204 women, I² = 37%, very low-quality evidence), or babies with neonatal acidosis (average RR 0.89, 95% CI 0.07 to 12.00, 3 studies, 175 babies, low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (321 babies; low-quality evidence). Ondansetron versus control Ondansetron administration was more effective than control (placebo saline) for preventing hypotension requiring treatment (average RR 0.67, 95% CI 0.54 to 0.83; 740 women, 8 studies, low-quality evidence), bradycardia requiring treatment (average RR 0.49, 95% CI 0.28 to 0.87; 740 women, 8 studies, low-quality evidence), and nausea and/or vomiting (average RR 0.35, 95% CI 0.24 to 0.51; 653 women, 7 studies, low-quality evidence). There was no clear difference between the groups in rates of neonatal acidosis (average RR 0.48, 95% CI 0.05 to 5.09; 134 babies; 2 studies, low-quality evidence) or Apgar scores of less than 8 at five minutes (284 babies, low-quality evidence). Lower limb compression versus control Lower limb compression was more effective than control for preventing hypotension (average RR 0.61, 95% CI 0.47 to 0.78, 11 studies, 705 women, I² = 65%, very low-quality evidence). There was no clear difference between the groups in rates of bradycardia (RR 0.63, 95% CI 0.11 to 3.56, 1 study, 74 women, very low-quality evidence) or nausea and/or vomiting (average RR 0.42, 95% CI 0.14 to 1.27, 4 studies, 276 women, I² = 32%, very-low quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (130 babies, very low-quality evidence). Walking versus lying There was no clear difference between the groups for women with hypotension requiring treatment (RR 0.71, 95% CI 0.41 to 1.21, 1 study, 37 women, very low-quality evidence). Many included studies reported little to no information that would allow an assessment of their risk of bias, limiting our ability to draw meaningful conclusions. GRADE assessments of the quality of evidence ranged from very low to low. We downgraded evidence for limitations in study design, imprecision, and indirectness; most studies assessed only women scheduled for elective caesarean sections. External validity also needs consideration. Readers should question the use of colloids in this context given the serious potential side effects such as allergy and renal failure associated with their administration.

AUTHORS' CONCLUSIONS

While interventions such as crystalloids, colloids, ephedrine, phenylephrine, ondansetron, or lower leg compression can reduce the incidence of hypotension, none have been shown to eliminate the need to treat maternal hypotension in some women. We cannot draw any conclusions regarding rare adverse effects associated with use of the interventions (for example colloids) due to the relatively small numbers of women studied.

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.

Aortic Stenosis: What Risks Do the Stresses of Noncardiac Surgery or Pregnancy Pose and How Should They Be Managed?

Studies suggest that patients with aortic stenosis have increased risk in pregnancy and delivery and during anesthesia and surgery, although there are significant degrees of uncertainty as to the exact risks and best way to manage such patients. This article reviews current literature regarding impact of aortic stenosis on pregnancy and anesthesia during noncardiac surgery. There are shortcomings in the scientific evidence. Most of the available studies are observational and often retrospective and therefore there is a great deal of bias. This leads to difficulty in drawing conclusions in terms of how to apply the published information to clinical management.

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.

The Ghana PrenaBelt trial: a double-blind, sham-controlled, randomised clinical trial to evaluate the effect of maternal positional therapy during third-trimester sleep on birth weight

OBJECTIVE

To evaluate the effect, on birth weight and birth weight centile, of use of the PrenaBelt, a maternal positional therapy device, during sleep in the home setting throughout the third trimester of pregnancy.

DESIGN

A double-blind, sham-controlled, randomised clinical trial.

SETTING

Conducted from September 2015 to May 2016, at a single, tertiary-level centre in Accra, Ghana.

PARTICIPANTS

Two-hundred participants entered the study. One-hundred-eighty-one participants completed the study. Participants were women, 18 to 35 years of age, with low-risk, singleton, pregnancies in their third-trimester, with body mass index <35 kg/m² at the first antenatal appointment for the index pregnancy and without known foetal abnormalities, pregnancy complications or medical conditions complicating sleep.

INTERVENTIONS

Participants were randomised by computer-generated, one-to-one, simple randomisation to receive either the PrenaBelt or sham-PrenaBelt. Participants were instructed to wear their assigned device to sleep every night for the remainder of their pregnancy (approximately 12 weeks in total) and were provided a sleep diary to track their use. Allocation concealment was by unmarked, security-tinted, sealed envelopes. Participants and the outcomes assessor were blinded to allocation.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcomes were birth weight and birth weight centile. Secondary outcomes included adherence to using the assigned device nightly, sleeping position, pregnancy outcomes and feedback from participants and maternity personnel.

RESULTS

One-hundred-sixty-seven participants were included in the primary analysis. The adherence to using the assigned device nightly was 56%. The mean ±SD birth weight in the PrenaBelt group (n=83) was 3191g±483 and in the sham-PrenaBelt group (n=84) was 3081g±484 (difference 110 g, 95% CI -38 to 258, p=0.14). The median (IQR) customised birth weight centile in the PrenaBelt group was 43% (18 to 67) and in the sham-PrenaBelt group was 31% (14 to 58) (difference 7%, 95% CI -2 to 17, p=0.11).

CONCLUSIONS

The PrenaBelt did not have a statistically significant effect on birth weight or birth weight centile in comparison to the sham-PrenaBelt.

TRIAL REGISTRATION NUMBER

NCT02379728.

Maternal admissions to intensive care units in France: Trends in rates, causes and severity from 2010 to 2014

INTRODUCTION

Maternal intensive care unit admission is an indicator of severe maternal morbidity. The objective of this study was to estimate rates of maternal intensive care unit admission during or following pregnancy in France, and to describe the characteristics of women concerned, the severity of their condition, associated diagnoses, regional disparities, and temporal trends between 2010 and 2014.

METHODS

Women hospitalised in France in intensive care units during pregnancy or up to 42 days after pregnancy between January 2010 and December 2014 were identified using the national hospital discharge database (PMSI-MCO). Trends in incidence rates were quantified using percentages of average annual variation based on a Poisson regression model.

RESULTS

In total, 16,011 women were admitted to intensive care units, representing an overall incidence of 3.97‰ deliveries. This number decreased significantly by 1.7% on average per year. For women who gave birth (60.5% by C-section), 62.5% of admissions occurred during their hospitalisation for delivery. The SAPS II score, an indicator of severity, significantly increased from 18.4 in 2010 to 21.5 in 2014. Obstetrical haemorrhage (39.8%) and hypertensive complications during pregnancy (24.8%) were the most common reasons for admission. In mainland France, the Ile-de-France (i.e., greater Paris) region had the highest rates of intensive care units admission (5.05‰) while the Pays-de-la-Loire region had the lowest (2.69‰).

CONCLUSION

The rate of maternal intensive care unit admission decreased from 2010 to 2014 in France, with a concomitant increase in case severity. In-depth studies are needed to understand the territorial disparities identified.

Echocardiographic determination of resting haemodynamics and optimal positioning in term pregnant women

Optimal positioning for anaesthesia in pregnant women involves balancing the need for ideal tracheal intubation conditions (achieved by the head elevated ramped position), with the prevention of reduced cardiac output from aortocaval compression (achieved by left lateral pelvic tilt). No studies have examined the effect on cardiac output of left lateral pelvic tilt in the ramped position. We studied non-labouring, non-anaesthetised healthy term pregnant women who underwent baseline (left lateral decubitus) cardiac assessment using transthoracic echocardiography. We then compared cardiac output, maternal physiological variables, fetal heart rate and comfort scores in three positions: left lateral decubitus; ramped position with wedge; and ramped position alone. Thirty women completed the study. Mean (SD) age, gestation and body mass index were 33.5 (3.93) years, 38.5 (0.94) weeks and 29.0 (4.0) kg.m^-2 , respectively. Mean ejection fraction, left ventricular internal diameter and mitral valve E/e' were 55.2 (6.8) %, 4.70 (0.43) cm and 7.50 (1.82), respectively. There were no differences in cardiac output between the positions (p = 0.503). There were no differences in systolic (p = 0.955) or diastolic (p = 0.987) blood pressure, maternal heart rate (p = 0.133), oxygen saturation, respiratory rate (p = 0.964) or fetal heart rate (p = 0.361) between ramped with wedge and ramped alone positions. Left lateral decubitus was most comfortable (p = 0.001), however, there were no differences in comfort levels between ramped with wedge and ramped alone positions. The ramped position without left lateral tilt is safe and acceptable in non-labouring, non-anaesthetised, healthy term pregnant women. Left lateral pelvic tilt may be unnecessary in the head elevated ramped position in term pregnant women.

Modifying maternal sleep position in the third trimester of pregnancy with positional therapy: a randomised pilot trial

OBJECTIVE

To evaluate whether the percentage of time spent supine during sleep in the third trimester of pregnancy could be reduced using a positional therapy device (PrenaBelt) compared with a sham device.

DESIGN

A double-blind, randomised, sham-controlled, cross-over pilot trial.

SETTING

Conducted between March 2016 and January 2017, at a single, tertiary-level centre in Canada.

PARTICIPANTS

23 participants entered the study. 20 participants completed the study. Participants were low-risk, singleton, third-trimester pregnant women aged 18 years and older with body mass index <35 kg/m² at the first antenatal appointment for the index pregnancy and without known fetal abnormalities, pregnancy complications or medical conditions complicating sleep.

INTERVENTIONS

A two-night, polysomnography study in a sleep laboratory. Participants were randomised by computer-generated, one-to-one, simple randomisation to receive either a PrenaBelt or a sham-PrenaBelt on the first night and were crossed over to the alternate device on the second night. Allocation concealment was by unmarked, security-tinted, sealed envelopes. Participants, the recruiter and personnel involved in setting up, conducting, scoring and interpreting the polysomnogram were blinded to allocation.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the percentage of time spent supine during sleep. Secondary outcomes included maternal sleep architecture, respiration, self-reported sleep position and feedback.

RESULTS

The median percentage of sleep time supine was reduced from 16.4% on the sham night to 3.5% on the PrenaBelt night (pseudomedian=5.8, p=0.03). We were unable to demonstrate differences in sleep architecture or respiration. Participants underestimated the time they spent sleeping supine by 7.0%, and six (30%) participants indicated they would make changes to the PrenaBelt. There were no harms in this study.

CONCLUSIONS

This study demonstrates that the percentage of sleep time supine during late pregnancy can be significantly reduced via positional therapy.

TRIAL REGISTRATION NUMBER

NCT02377817; Results.

Modifying Maternal Sleep Position in Late Pregnancy Through Positional Therapy: A Feasibility Study

STUDY OBJECTIVES

To test whether a customized positional therapy device, PrenaBelt, would reduce time spent sleeping supine and evaluate any change in maternal or fetal parameters, in a group of healthy pregnant women in the third trimester of pregnancy.

METHODS

Participants underwent an in-home, overnight sleep study during late pregnancy (32-38 weeks). Participants were observed over 2 nights: 1 night when the PrenaBelt was not worn (nonintervention or control) and 1 night when it was (intervention). The intervention night was randomly allocated, and the study nights were consecutive. On the control night, participants were filmed using a night-capable (infrared) video camera, maternal sleep was measured by the Watch-PAT200, and the fetus was continuously monitored using the Monica AN24. On the intervention night, video, maternal, and fetal monitoring were repeated with the addition of the mother wearing the PrenaBelt.

RESULTS

A total of 25 healthy pregnant women were studied. Four had missing data for the Watch-PAT or Monica, and eight had missing or disrupted video data. Video-determined time in bed was not significantly different during intervention and control nights (P = .196, r = -.23). Median time spent supine during the intervention night was reduced from 48.3 minutes, to 28.5 minutes during the control night (P = .064, r = -.33). The difference in the proportion of time spent supine was significant (P = .039). There was no significant difference in objectively estimated sleep time (P = .651, r = -.07). Improvement was observed in both maternal and fetal parameters during the intervention night with an increase in median minimum maternal oxygen saturations (control = 91.6%, intervention = 92.4%, P = .006, r = -.42), fewer maternal oxygen desaturations (control = 7.1, intervention = 5.9, P = .095, r = -.26), and fewer fetal heart rate decelerations (control = 14.0, intervention = 10.4, P = .045, r = -.31) compared to the control night.

CONCLUSIONS

Results provide preliminary evidence that an intervention to reduce supine sleep in late pregnancy may provide maternal and fetal health benefits, with minimal effect on maternal perception of sleep quality and objectively estimated sleep time. Further research to explore relationships between objectively determined maternal sleep position, maternal respiratory indices, and fetal well-being is warranted.

Hemodynamic effects of lateral tilt before and after spinal anesthesia during cesarean delivery: an observational study

Background

Post-spinal hypotension is a common maternal complication during cesarean delivery. Aortocaval compression by the gravid uterus has been assumed as a precipitating factor for post-spinal hypotension. The role of left lateral tilting position in improving maternal cardiac output after subarachnoid block (SAB) is unclear. The aim of this work is to investigate the effect of left lateral tilting on maternal hemodynamics after SAB.

Methods

A prospective observational study was conducted including 105 full term pregnant women scheduled for cesarean delivery. Mean arterial pressure, heart rate, cardiac output (measured by electrical cardiometry), stroke volume, and systemic vascular resistance were recorded in three positions (supine, 15⁰, and 30⁰ left lateral positions) before SAB, after SAB, and after delivery of the fetus.

Results

Before SAB, no significant hemodynamic changes were reported with left lateral tilting. A significant decrease was reported in mean arterial pressure, cardiac output, stroke volume, and systemic vascular resistance after SAB (in supine position). When performing left lateral tilting, there was an increase in cardiac output, heart rate, and mean arterial pressure. No difference was reported between the two tilt angles (15⁰ and 30⁰).

Conclusions

Changing position of full term pregnant woman after SAB from supine to left lateral tilted position results increased cardiac output and mean arterial pressure. There is no difference between the two tilt angles (15⁰ and 30⁰).

Trial registration

clinicaltrials.gov (NCT02828176) retrospectively registered.

Focused cardiac ultrasound is feasible in parturients; a prospective observational study

BACKGROUND

In pregnancy, the major causes of morbidity and mortality include diseases that affect circulation profoundly and restoration of normal circulation is a key objective. Focused cardiac ultrasound provides information on the individual determinants of circulation and has a significant impact on patient management. This study aimed to determine the feasibility of focused cardiac ultrasound in term parturients.

METHODS

Forty parturients underwent focused cardiac ultrasound. Parasternal long-axis, parasternal short-axis, 4-chamber and subcostal views were performed in the left-lateral position and the supine position by a novice operator. All images were graded on the following scale: 1 = no image; 2 = poor and insufficient image; 3 = sufficient image quality; 4 = good image quality; 5 = perfect image quality. A cut-off grade of three signified images sufficient for clinical decision-making.

RESULTS

Images sufficient for clinical decision-making were obtained in all patients when including all imaging views. 37/40 (93 %) patients presented images of grade ≥ 4, whereas 10/40 (25%) patients had images of grade 5. Image grades were higher in the left lateral position (all P < 0.001). Parturients with a body mass index ≤ 30 kg/m² did not present different image grades than parturients with a higher body mass index (P = 0.753). Subcostal views could not be obtained.

CONCLUSION

Focused cardiac ultrasound is feasible in the obstetric population and images of sufficient quality for clinical decision-making were obtained in all parturients by an operator with limited experience.

Techniques for preventing hypotension during spinal anaesthesia for caesarean section

BACKGROUND

Maternal hypotension is the most frequent complication of spinal anaesthesia for caesarean section. It can be associated with nausea or vomiting and may pose serious risks to the mother (unconsciousness, pulmonary aspiration) and baby (hypoxia, acidosis, neurological injury).

OBJECTIVES

To assess the effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (9 August 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials, including full texts and abstracts, comparing interventions to prevent hypotension with placebo or alternative treatment in women having spinal anaesthesia for caesarean section. We excluded studies if hypotension was not an outcome measure.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data from eligible studies. We report 'Summary of findings' tables using GRADE.

MAIN RESULTS

We included 126 studies involving 9565 participants. Interventions were to prevent maternal hypotension following spinal anaesthesia only, and we excluded any interventions considered active treatment. All the included studies reported the review's primary outcome. Across 49 comparisons, we identified three intervention groups: intravenous fluids, pharmacological interventions, and physical interventions. Authors reported no serious adverse effects with any of the interventions investigated. Most trials reported hypotension requiring intervention and Apgar score of less than 8 at five minutes as the only outcomes. None of the trials included in the comparisons we describe reported admission to neonatal intensive care unit. Crystalloid versus control (no fluids)Fewer women experienced hypotension in the crystalloid group compared with no fluids (average risk ratio (RR) 0.84, 95% confidence interval (CI) 0.72 to 0.98; 370 women; 5 studies; low-quality evidence). There was no clear difference between groups in numbers of women with nausea and vomiting (average RR 0.19, 95% CI 0.01 to 3.91; 1 study; 69 women; very low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (60 babies, low-quality evidence). Colloid versus crystalloidFewer women experienced hypotension in the colloid group compared with the crystalloid group (average RR 0.68, 95% CI 0.58 to 0.80; 2105 women; 28 studies; very low-quality evidence). There were no clear differences between groups for maternal hypertension requiring intervention (average RR 0.64, 95% CI 0.09 to 4.46, 3 studies, 327 women;very low-quality evidence), maternal bradycardia requiring intervention (average RR 0.99, 95% CI 0.55 to 1.79, 6 studies, 509 women; very low-quality evidence), nausea and/or vomiting (average RR 0.83, 95% CI 0.61 to 1.13, 15 studies, 1154 women, I² = 37%; very low-quality evidence), neonatal acidosis (average RR 0.83, 95% CI 0.15 to 4.52, 6 studies, 678 babies; very low-quality evidence), or Apgar score of less than 8 at five minutes (average RR 0.24, 95% CI 0.03 to 2.05, 11 studies, 826 babies; very low-quality evidence). Ephedrine versus phenylephrineThere were no clear differences between ephedrine and phenylephrine groups for preventing maternal hypotension (average RR 0.92, 95% CI 0.71 to 1.18; 401 women; 8 studies; very low-quality evidence) or hypertension (average RR 1.72, 95% CI 0.71 to 4.16, 2 studies, 118 women, low-quality evidence). Rates of bradycardia were lower in the ephedrine group (average RR 0.37, 95% CI 0.21 to 0.64, 5 studies, 304 women, low-quality evidence). There was no clear difference in the number of women with nausea and/or vomiting (average RR 0.76, 95% CI 0.39 to 1.49, 4 studies, 204 women, I² = 37%, very low-quality evidence), or babies with neonatal acidosis (average RR 0.89, 95% CI 0.07 to 12.00, 3 studies, 175 babies, low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (321 babies; low-quality evidence). Ondansetron versus controlOndansetron administration was more effective than control (placebo saline) for preventing hypotension requiring treatment (average RR 0.67, 95% CI 0.54 to 0.83; 740 women, 8 studies, low-quality evidence), bradycardia requiring treatment (average RR 0.49, 95% CI 0.28 to 0.87; 740 women, 8 studies, low-quality evidence), and nausea and/or vomiting (average RR 0.35, 95% CI 0.24 to 0.51; 653 women, 7 studies, low-quality evidence). There was no clear difference between the groups in rates of neonatal acidosis (average RR 0.48, 95% CI 0.05 to 5.09; 134 babies; 2 studies, low-quality evidence) or Apgar scores of less than 8 at five minutes (284 babies, low-quality evidence). Lower limb compression versus controlLower limb compression was more effective than control for preventing hypotension (average RR 0.61, 95% CI 0.47 to 0.78, 11 studies, 705 women, I² = 65%, very low-quality evidence). There was no clear difference between the groups in rates of bradycardia (RR 0.63, 95% CI 0.11 to 3.56, 1 study, 74 women, very low-quality evidence) or nausea and/or vomiting (average RR 0.42 , 95% CI 0.14 to 1.27, 4 studies, 276 women, I² = 32%, very-low quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (130 babies, very low-quality evidence). Walking versus lyingThere was no clear difference between the groups for women with hypotension requiring treatment (RR 0.71, 95% CI 0.41 to 1.21, 1 study, 37 women, very low-quality evidence).Many included studies reported little to no information that would allow an assessment of their risk of bias, limiting our ability to draw meaningful conclusions. GRADE assessments of the quality of evidence ranged from very low to low. We downgraded evidence for limitations in study design, imprecision, and indirectness; most studies assessed only women scheduled for elective caesarean sections.External validity also needs consideration. Readers should question the use of colloids in this context given the serious potential side effects such as allergy and renal failure associated with their administration.

AUTHORS' CONCLUSIONS

While interventions such as crystalloids, colloids, ephedrine, phenylephrine, ondansetron, or lower leg compression can reduce the incidence of hypotension, none have been shown to eliminate the need to treat maternal hypotension in some women. We cannot draw any conclusions regarding rare adverse effects associated with use of the interventions (for example colloids) due to the relatively small numbers of women studied.

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

Background

Current recommendations for women undergoing cesarean delivery include 15° left tilt for uterine displacement to prevent aortocaval compression, although this degree of tilt is practically never achieved. We hypothesized that under contemporary clinical practice, including a crystalloid coload and phenylephrine infusion targeted at maintaining baseline systolic blood pressure, there would be no effect of maternal position on neonatal acid base status in women undergoing elective cesarean delivery with spinal anesthesia.

Methods

Healthy women undergoing elective cesarean delivery were randomized (nonblinded) to supine horizontal (supine, n = 50) or 15° left tilt of the surgical table (tilt, n = 50) after spinal anesthesia (hyperbaric bupivacaine 12 mg, fentanyl 15 μg, preservative-free morphine 150 μg). Lactated Ringer’s 10 ml/kg and a phenylephrine infusion titrated to 100% baseline systolic blood pressure were initiated with intrathecal injection. The primary outcome was umbilical artery base excess.

Results

There were no differences in umbilical artery base excess or pH between groups. The mean umbilical artery base excess (± SD) was −0.5 mM (± 1.6) in the supine group (n = 50) versus −0.6 mM (± 1.5) in the tilt group (n = 47) (P = 0.64). During 15 min after spinal anesthesia, mean phenylephrine requirement was greater (P = 0.002), and mean cardiac output was lower (P = 0.014) in the supine group.

Conclusions

Maternal supine position during elective cesarean delivery with spinal anesthesia in healthy term women does not impair neonatal acid–base status compared to 15° left tilt, when maternal systolic blood pressure is maintained with a coload and phenylephrine infusion. These findings may not be generalized to emergency situations or nonreassuring fetal status.

Preeclampsia and the brain: neural control of cardiovascular changes during pregnancy and neurological outcomes of preeclampsia

Preeclampsia (PE) is a form of gestational hypertension that complicates ∼5% of pregnancies worldwide. Over 70% of the fatal cases of PE are attributed to cerebral oedema, intracranial haemorrhage and eclampsia. The aetiology of PE originates from abnormal remodelling of the maternal spiral arteries, creating an ischaemic placenta that releases factors that drive the pathophysiology. An initial neurological outcome of PE is the absence of the autonomically regulated cardiovascular adaptations to pregnancy. PE patients exhibit sympathetic overactivation, in comparison with both normotensive pregnant and hypertensive non-pregnant females. Moreover, PE diminishes baroreceptor reflex sensitivity (BRS) beyond that observed in healthy pregnancy. The absence of the cardiovascular adaptations to pregnancy, combined with sympathovagal imbalance and a blunted BRS leads to life-threatening neurological outcomes. Behaviourally, the increased incidences of maternal depression, anxiety and post-traumatic stress disorder (PTSD) in PE are correlated to low fetal birth weight, intrauterine growth restriction (IUGR) and premature birth. This review addresses these neurological consequences of PE that present in the gravid female both during and after the index pregnancy.