What’s new in obstetric anesthesia? Focus on preeclampsia

Pr-AKI: Acute Kidney Injury in Pregnancy – Etiology, Diagnostic Workup, Management

Despite significant improvements in inpatient and outpatient management, pregnancy-related acute kidney injury (Pr-AKI) remains an important risk factor for early and late maternal and fetal morbidity and mortality. There is a discrepancy between the incidence of Pr-AKI in developing and in developed countries, with the former experiencing a decrease and the latter an increase in Pr-AKI in recent decades. Whereas septic and hemorrhagic complications predominated in the past, nowadays hypertensive disorders and thrombotic microangiopathy are the leading causes of Pr-AKI. Modern lifestyles and the availability and widespread use of in-vitro fertilization techniques in industrialized countries have allowed more women of advanced age to become pregnant. This has led to a rise in the percentage of high-risk pregnancies due to the disorders and comorbidities inherent to or accompanying aging, such as diabetes, arterial hypertension and preexisting chronic kidney disease. Last but not least, the heterogeneity of symptoms, the often overlapping clinical and laboratory characteristics and the pathophysiological changes related to pregnancy make the diagnosis and management of Pr-AKI a difficult and challenging task for the treating physician. In addition to general supportive management strategies such as volume substitution, blood pressure control, prevention of seizures or immediate delivery, each disease entity requires a specific therapy to reduce maternal and fetal complications. In this review, we used the current literature to provide a summary of the physiologic and pathophysiologic changes in renal physiology which occur during pregnancy. In the second part, we present common and rare disorders which lead to Pr-AKI and provide an overview of the available treatment options.

Hypoxaemia during tracheal intubation in patients with hypertensive disorders of pregnancy: analysis of data from an obstetric airway management registry

BACKGROUND

In South Africa, hypertensive disorders of pregnancy are the leading cause of maternal mortality. More than 50% of anaesthesia-related maternal deaths are attributed to complications of airway management. We compared the prevalence and risk factors for hypoxaemia during induction of general anaesthesia in parturients with and without hypertensive disorders of pregnancy. We hypothesised that hypertensive disorders of pregnancy are associated with desaturation during tracheal intubation.

METHODS

Data from 402 cases in a multicentre obstetric airway management registry were analysed. The prevalence of peri-induction hypoxaemia (SpO₂ <90%) was compared in patients with and without hypertensive disorders of pregnancy. Quantile regression of SpO₂ nadir was performed to identify confounding variables associated with, and mediators of, hypoxaemia.

RESULTS

In the cohort of 402 cases, hypoxaemia occurred in 19% with and 9% without hypertension (estimated risk difference, 10%; 95% CI 2% to 17%; P=0.005). Quantile regression demonstrated a lower SpO₂ nadir associated with hypertensive disorders of pregnancy as body mass index increased. Room-air oxygen saturation, Mallampati grade, and number of intubation attempts were associated with the relationship.

CONCLUSIONS

Clinically significant oxygen desaturation during airway management occurred twice as often in patients with hypertensive disorders of pregnancy, compounded by increasing body mass index. Intermediary factors in the pathway from hypertension to hypoxaemia were also identified.

Distinct expression profiles of peptides in placentae from preeclampsia and normal pregnancies

This study sought to identify potential bioactive peptides from the placenta that are involved in preeclampsia (PE) to obtain information about the prediction, diagnosis and treatment of PE. The liquid chromatography/mass spectrometry was used to perform a comparative analysis of placental peptides in normal and PE pregnancies. Gene ontology (GO), pathway analysis and ingenuity pathway analysis (IPA) were used to evaluate the underlying biological function of the differential peptides based on their protein precursors. Transwell assays and qPCR were used to study the effect of the identified bioactive peptides on the function of HTR-8/SVneo cells. A total of 392 upregulated peptides and 420 downregulated peptides were identified (absolute fold change ≥ 2 and adjusted P value < 0.05). The GO analysis, pathway analysis, and IPA revealed that these differentially expressed peptides play a role in PE. In addition, the up-regulated peptide “DQSATALHFLGRVANPLSTA” derived from Angiotensinogen exhibited effect on the invasiveness of HTR-8/SVneo cells. The current preliminary research not only provides a new research direction for studying the pathogenesis of PE, but also brings new insights for the prediction, diagnosis and treatment of PE.

Preeclampsia and the anaesthesiologist: current management

PURPOSE OF REVIEW

Preeclampsia remains an important cause of maternal and neonatal morbidity and mortality. Recent interest in angiogenic biomarkers as a prognostic indicator is reviewed, together with analgesic, anaesthetic and critical-care management of the preeclamptic patient.

RECENT FINDINGS

There has been recent interest in the angiogenic biomarkers placental growth factor and soluble fms-like tyrosine kinase-1 in establishing the diagnosis of preeclampsia and guiding its management. Neuraxial blocks are recommended for both labour and operative delivery if not contraindicated by thrombocytopenia or coagulopathy, although a safe lower limit for platelet numbers has not been established. For spinal hypotension phenylephrine is noninferior to ephedrine in preeclamptic parturients and may offer some benefits. When general anaesthesia is required, efforts must be made to blunt the hypertensive response to laryngoscopy and intubation. Transthoracic echocardiography has emerged as useful technique to monitor maternal haemodynamics in preeclampsia.

SUMMARY

Improvements in the diagnosis of preeclampsia may lead to better outcomes for mothers and babies. Peripartum care requires a multidisciplinary team approach with many preeclamptic women receiving neuraxial analgesia or anaesthesia. Women with severe preeclampsia may require critical-care support and this should meet the same standards afforded to other acutely unwell patients.

Point-of-Care Ultrasound Abnormalities in Late-Onset Severe Preeclampsia: Prevalence and Association With Serum Albumin and Brain Natriuretic Peptide

BACKGROUND

Pilot studies applying point-of-care ultrasound (POCUS) in preeclampsia indicate the presence of pulmonary interstitial edema, cerebral edema, and cardiac dysfunction. Laboratory markers of oncotic pressure (albumin) and cardiac dysfunction (brain natriuretic peptide [BNP]) may be abnormal, but the clinical application remains unclear. We investigated the prevalence of pulmonary interstitial syndrome (PIS), cardiac dysfunction, and increased optic nerve sheath diameter (ONSD) in late-onset preeclampsia with severe features. The primary aim was to examine the association between PIS or ONSD and maternal serum albumin level. The secondary aims were to explore the association between cardiac dysfunction and PIS, ONSD, BNP, and serum albumin level and between POCUS-derived parameters and a suspicious or pathological cardiotocograph.

METHODS

Ninety-five women were enrolled in this prospective observational cohort study. A POCUS examination of lungs, heart, and ONSD was performed. PIS was defined as a bilateral B-line pattern on lung ultrasound and diastolic dysfunction according to an algorithm of the American Society of Echocardiography. ONSD >5.8 mm was interpreted as compatible with raised intracranial pressure (>20 mm Hg). Serum BNP and albumin levels were also measured.

RESULTS

PIS, diastolic dysfunction, systolic dysfunction, and raised left ventricular end-diastolic pressure (LVEDP) were present in 23 (24%), 31 (33%), 9 (10%), and 20 (25%) women, respectively. ONSD was increased in 27 (28%) women. Concerning the primary outcome, there was no association between albumin level and PIS (P = .4) or ONSD (P = .63). With respect to secondary outcomes, there was no association between albumin level and systolic dysfunction (P = .21) or raised LVEDP (P = .44). PIS was associated with diastolic dysfunction (P = .02) and raised LVEDP (P = .009; negative predictive value, 85%). BNP level was associated with systolic (P < .001) and diastolic dysfunction (P = .003) and LVEDP (P = .007). No association was found between POCUS abnormalities and a suspicious/pathological cardiotocograph (P = .07).

CONCLUSIONS

PIS, diastolic dysfunction, and increased ONSD were common in preeclampsia with severe features. Cardiac ultrasound abnormalities may be more useful than albumin levels in predicting PIS. The absence of PIS may exclude raised LVEDP. The further clinical relevance of PIS and raised ONSD remains to be established. BNP level was associated with cardiac ultrasound abnormalities. Although this study was not designed to directly influence clinical management, the findings suggest that POCUS may serve as a useful adjunct to clinical examination for the obstetric anesthesiologist managing these complex patients.

Comparison of the effects of low doses of dexmedetomidine and remifentanil on the maternal hemodynamic changes during caesarean delivery in patients with severe preeclampsia: a randomized trial

BACKGROUND

Preoperative remifentanil administration blunts hemodynamic responses to tracheal intubation in parturients with severe preeclampsia. We hypothesized that the preoperative administration of low doses of remifentanil or dexmedetomidine would lead to comparable maternal neurohormonal responses and neonatal outcomes in patients with severe preeclampsia.

METHODS

Parturients diagnosed with severe preeclampsia undergoing caesarean delivery were randomLy allocated to receive remifentanil (0.1 µg/kg/min) or dexmedetomidine (0.4 µg/kg/h) at five min and 20 min before induction, respectively. Changes in maternal mean arterial BP(MAP), clinical recovery, cortisol level, and neonatal outcome, were recorded.

RESULTS

Patients who received remifentanil had higher response in MAP at the induction (94 9.8 vs. 104 4.5; P<0.001) and emergence from anesthesia (94 6.3 vs. 98 5.1; P<0.001), but shorter times to extubation (5.1 1.6 vs. 13.5 2.8 min; P<0.001). Five (27.8%) patients in the remifentanil group received ephedrine versus none in the dexmedetomidine group (P=0.023). The maternal plasma cortisol levels, the neonatal Neurologic and Adaptative Capacity Scores and acid-base satuses were similar in the two groups. Newborns in the remifentanil group presented lower Apgar scores at 1 minute (5.11 0.8 vs. 5.68 0.8; P=0.034) and a higher incidence of respiratory depression (72.2% vs. 36.8% P=0.048).

CONCLUSIONS

Compared with dexmedetomidine (0.4 µg/kg/h), the preoperative administration of remifentanil (0.1 µg/kg/min) produced a significantly higher effect on maternal hemodynamic responses to caesarean delivery in patients with severe preeclampsia, however maternal hypotension and neonatal respiratory depression were more common with the use of remifentanil.

Long Non-Coding RNAs Serve as Diagnostic Biomarkers of Preeclampsia and Modulate Migration and Invasiveness of Trophoblast Cells

Background

Long non-coding RNAs (lncRNAs) have emerged as crucial regulators of tumor progression. However, the effects of lncRNAs in preeclampsia are not entirely clear. The aim of this study was to demonstrate the potential of lncRNAs to serve as biomarkers in preeclampsia.

Material/Methods

The RNA expression levels of lncRNAs (NR_027457, BC030099, AF037219, NR_024178, AF085938, G43016, G36948, NR_029420, NR_024015, AK002210, NR_026643, and AL049277) in the serum of patients with preeclampsia and in the serum of normal controls were measured by qRT-PCR. The area under the curve (AUC), the optimal cut-off values, the specificity, and the sensitivity of NR_027457, AF085938, G36948, and AK002210 were analyzed by receiver operating characteristic (ROC) curve analysis. We designed RNA interference species to suppress NR_027457 and G36948 and identified the roles of NR_027457 and G36948 in the functions of a trophoblast cell line (HTR-8/SVneo).

Results

The qRT-PCR results indicated that NR_027457 and AF085938 were significantly up-regulated, whereas G36948 and AK002210 were significantly down-regulated in preeclampsia. We found that NR_027457, AF085938, G36948, and AK002210 had potential diagnostic value for the detection of preeclampsia. Furthermore, the levels of NR_027457, AF085938, G36948, and AK002210 in the serum of patients were significantly different before vs. after surgery. The silencing of NR_027457 inhibited the proliferation, migration, and invasion abilities of HTR-8/SVneo cells, while the silencing of G36948 promoted the proliferation, migration, and invasion abilities of HTR-8/SVneo cells.

Conclusions

NR_027457, AF085938, G36948, and AK002210 can serve as potential diagnostic biomarkers in preeclampsia, and NR_027457 and G36948 might be involved in the pathogenesis of preeclampsia.

Practice Bulletin No. 177: Obstetric Analgesia and Anesthesia

Labor causes severe pain for many women. There is no other circumstance in which it is considered acceptable for an individual to experience untreated severe pain that is amenable to safe intervention while the individual is under a physician's care. Many women desire pain management during labor and delivery, and there are many medical indications for analgesia and anesthesia during labor and delivery. In the absence of a medical contraindication, maternal request is a sufficient medical indication for pain relief during labor. A woman who requests epidural analgesia during labor should not be deprived of this service based on the status of her health insurance. Third-party payers that provide reimbursement for obstetric services should not deny reimbursement for labor analgesia because of an absence of "other medical indications." Anesthesia services should be available to provide labor analgesia and surgical anesthesia in all hospitals that offer maternal care (levels I-IV) (). Although the availability of different methods of labor analgesia will vary from hospital to hospital, the methods available within an institution should not be based on a patient's ability to pay.The American College of Obstetricians and Gynecologists believes that in order to allow the maximum number of patients to benefit from neuraxial analgesia, labor nurses should not be restricted from participating in the management of pain relief during labor. Under appropriate physician supervision, labor and delivery nursing personnel who have been educated properly and have demonstrated current competence should be able to participate in the management of epidural infusions.The purpose of this document is to review medical options for analgesia during labor and anesthesia for surgical procedures that are common at the time of delivery. Nonpharmacologic options such as massage, immersion in water during the first stage of labor, acupuncture, relaxation, and hypnotherapy are not covered in this document, though they may be useful as adjuncts or alternatives in many cases.

Obstetrical, pregnancy and socio-economic predictors for new-onset severe postpartum psychiatric disorders in primiparous women

BACKGROUND

Childbirth is a potent trigger for the onset of psychiatric illness in women including postpartum depression (PPD) and postpartum psychosis (PP). Medical complications occurring during pregnancy and/or childbirth have been linked to postpartum psychiatric illness and sociodemographic factors. We evaluated if pregnancy and obstetrical predictors have similar effects on different types of postpartum psychiatric disorders.

METHOD

A population-based cohort study using Danish registers was conducted in 392 458 primiparous women with a singleton delivery between 1995 and 2012 and no previous psychiatric history. The main outcome was first-onset postpartum psychiatric episodes. Incidence rate ratios (IRRs) were calculated for any psychiatric contact in four quarters for the first year postpartum.

RESULTS

PPD and postpartum acute stress reactions were associated with pregnancy and obstetrical complications. For PPD, hyperemesis gravidarum [IRR 2.69, 95% confidence interval (CI) 1.93-3.73], gestational hypertension (IRR 1.84, 95% CI 1.33-2.55), pre-eclampsia (IRR 1.45, 95% CI 1.14-1.84) and Cesarean section (C-section) (IRR 1.32, 95% CI 1.13-1.53) were associated with increased risk. For postpartum acute stress, hyperemesis gravidarum (IRR 1.93, 95% CI 1.38-2.71), preterm birth (IRR 1.51, 95% CI 1.30-1.75), gestational diabetes (IRR 1.42, 95% CI 1.03-1.97) and C-section (IRR 1.36, 95% CI 1.20-1.55) were associated with increased risk. In contrast, risk of PP was not associated with pregnancy or obstetrical complications.

CONCLUSIONS

Pregnancy and obstetrical complications can increase the risk for PPD and acute stress reactions but not PP. Identification of postpartum women requiring secondary care is needed to develop targeted approaches for screening and treatment. Future work should focus on understanding the contributions of psychological stressors and underlying biology on the development of postpartum psychiatric illness.

Hypertensive disorders of pregnancy

PURPOSE

In this continuing professional development module, we review recent Society of Obstetricians and Gynaecologists of Canada (SOGC) guidelines for the classification and diagnosis of hypertensive disorders of pregnancy (HDP) as well as review the clinical features, laboratory investigations, and outcomes of HDP. We explore the evidence for anesthetic management and prevention of end-organ damage in women with HDP and describe the role and contribution of anesthesiologists as part of a multidisciplinary care team.

PRINCIPAL FINDINGS

Hypertensive disorders of pregnancy can have variable presentations with clinical signs and symptoms that often do not correlate with the underlying severity and progression of the disease. Failure of timely diagnosis and treatment contributes significantly to adverse maternal (neurologic complications, pulmonary edema, and postpartum hemorrhage) and neonatal (respiratory and neurologic complications and stillbirth) outcomes. In the Canadian context, improvements in medical care have led to better maternal and neonatal outcomes. Timing of delivery is crucial in balancing maternal risks and fetal benefits of ongoing pregnancy. Evidence-based SOGC guidelines regarding diagnosis and management of HDP address many aspects of clinical care relevant to anesthesiologists, who have an important role in the multidisciplinary care team.

CONCLUSIONS

Hypertensive disorders of pregnancy are on the rise worldwide, and this trend is expected to continue. The major contributors to maternal mortality are failure to recognize HDP promptly or to treat the condition adequately. It is essential that anesthesiologists understand the disease process and acquire knowledge of the guidelines governing current obstetrical care in order to provide evidence-based multidisciplinary quality care to these patients. Anesthetic management helps prevent potentially deleterious maternal and fetal outcomes.