Infection in obstetric critical care

Lactate and procalcitonin levels in peripartum women with intraamniotic infection

BACKGROUND

Pregnant women are vulnerable to infection as their immune response is modulated.

OBJECTIVE

Serum biomarkers are used to diagnose and manage severe infections, but data on their utility during labor are limited. We compared lactate and procalcitonin levels in women with and without an intraamniotic infection to determine whether they are useful biomarkers for infection during labor.

STUDY DESIGN

We performed a prospective, observational cohort study of term, singleton pregnancies admitted with planned vaginal delivery in 2019 at a university medical center. The lactate and procalcitonin levels were determined during early labor, within 2 hours following delivery, and on postpartum day 1. Women with an intraamniotic infection in addition had their lactate and procalcitonin levels determined following an intraamniotic infection diagnosis. Samples were processed immediately in the hospital clinical laboratory. The primary outcome was the mean lactate level following delivery. The secondary outcomes were the lactate and procalcitonin levels at other time points. Comparisons based on infection status were performed using multivariate linear regressions.

RESULTS

A total of 22 women with intraamniotic infection and 29 uninfected women were included. The mean early labor lactate level (1.47 vs 1.49 mmol/L) and mean procalcitonin level (0.048 vs 0.039 ng/mL) did not differ and were normal in the uninfected and intraamniotic infection groups. The mean lactate level was highest following delivery for women in both the uninfected and intraamniotic infection groups (2.00 vs 2.33 mmol/L; adjusted P=.08; 95% confidence interval, 0.98-1.53). The lactate level returned to normal by postpartum day 1 and did not differ significantly based on the infection status at any time point in the adjusted models. The procalcitonin level following delivery was higher among women with vs without an intraamniotic infection (0.142 vs 0.091 ng/mL; adjusted P=.03). The procalcitonin level rose further in both the intraamniotic infection and uninfected groups on postpartum day 1 (0.737 vs 0.408 ng/mL; adjusted P=.05).

CONCLUSION

The lactate level is not significantly elevated in pregnant women with an intraamniotic infection above the physiological increase that is observed in women without infection at delivery. The procalcitonin level is elevated at delivery in women with an intraamniotic infection and warrants further investigation as a peripartum infection marker.

Sepsis in pregnancy and the puerperium

Sepsis remains a leading cause of maternal morbidity and mortality. Recognition and treatment of maternal sepsis are often delayed due to the physiological adaptations of pregnancy and vague or absent signs and symptoms during its initial presentation. Over the past decade, our understanding of sepsis has evolved and maternal early warning systems have been developed in an effort to help providers promptly identify and stratify parturients who are at risk. In addition, new consensus definitions and care bundles have recently been published by the World Health Organization and the Surviving Sepsis Campaign to facilitate earlier recognition and timely management of sepsis. In this narrative review, we summarize the available evidence about sepsis and provide an overview of the research efforts focused on maternal sepsis to date. Controversies and challenges surrounding the anesthetic management of parturients with sepsis or at risk of developing sepsis during pregnancy or the puerperium will be highlighted.

Maternal sepsis in the era of genomic medicine

PURPOSE

Maternal sepsis remains one of the leading causes of direct and indirect maternal mortality both in high- and low-income environments. In the last two decades, systems biology approaches, based on '-omics' technologies, have started revolutionizing the diagnosis and management of the septic syndrome. The scope of this narrative review is to present an overview of the basic '-omics' technologies, exemplified by cases relevant to maternal sepsis.

METHODS

Narrative review of the new '-omics' technologies based on a detailed review of the literature.

RESULTS

After presenting the main 'omics' technologies, we discuss their limitations and the need for integrated approaches that encompass research efforts across multiple '-omics' layers in the '-omics' cascade between the genome and the phenome.

CONCLUSIONS

Systems biology approaches are revolutionizing the research landscape in maternal sepsis. There is a need for increased awareness, from the side of health practitioners, as a requirement for the effective implementation of the new technologies in the research and clinical practice in maternal sepsis.

Sepsis in Special Populations

Sepsis is recognized by the presence of physiologic and laboratory changes that reflect the inflammatory response to infection on cellular and systemic levels. Comorbid conditions, such as cirrhosis, end-stage renal disease, and obesity, alter patients' susceptibility to infection and their response to it once present. Baseline changes in vital signs and chronic medications often mask clues to the severity of illness. The physiologic, hematologic, and biochemical adjustments that accompany pregnancy and the puerperium introduce similar challenges. Emergency providers must remain vigilant for subtle alterations in the expected baseline for these conditions to arrive at appropriate management decisions.

Ending preventable maternal and newborn deaths due to infection

Over 300,000 maternal deaths occur each year, 11% of which are thought to be due to infectious causes, and approximately one million newborns die within the first week of life annually due to infectious causes. Infections in pregnancy may result in a variety of adverse obstetrical outcomes, including preterm delivery, pre-labor rupture of membranes, stillbirth, spontaneous abortion, congenital infection, and anomalies. This paper reviews the burden of disease due to key infections and their contribution to maternal, perinatal, and newborn morbidity and mortality, as well as key interventions to prevent maternal and newborn deaths related to these infections. Research needs include more accurate clinical and microbiologic surveillance systems, validated risk stratification strategies, better point-of-care testing, and identification of promising vaccine strategies.

Beyond maternal death: improving the quality of maternal care through national studies of ‘near-miss’ maternal morbidity

Background

Studies of maternal mortality have been shown to result in important improvements to women’s health. It is now recognised that in countries such as the UK, where maternal deaths are rare, the study of near-miss severe maternal morbidity provides additional information to aid disease prevention, treatment and service provision.

Objectives

To (1) estimate the incidence of specific near-miss morbidities; (2) assess the contribution of existing risk factors to incidence; (3) describe different interventions and their impact on outcomes and costs; (4) identify any groups in which outcomes differ; (5) investigate factors associated with maternal death; (6) compare an external confidential enquiry or a local review approach for investigating quality of care for affected women; and (7) assess the longer-term impacts.

Methods

Mixed quantitative and qualitative methods including primary national observational studies, database analyses, surveys and case studies overseen by a user advisory group.

Setting

Maternity units in all four countries of the UK.

Participants

Women with near-miss maternal morbidities, their partners and comparison women without severe morbidity.

Main outcome measures

The incidence, risk factors, management and outcomes of uterine rupture, placenta accreta, haemolysis, elevated liver enzymes and low platelets (HELLP) syndrome, severe sepsis, amniotic fluid embolism and pregnancy at advanced maternal age (≥ 48 years at completion of pregnancy); factors associated with progression from severe morbidity to death; associations between severe maternal morbidity and ethnicity and socioeconomic status; lessons for care identified by local and external review; economic evaluation of interventions for management of postpartum haemorrhage (PPH); women’s experiences of near-miss maternal morbidity; long-term outcomes; and models of maternity care commissioned through experience-led and standard approaches.

Results

Women and their partners reported long-term impacts of near-miss maternal morbidities on their physical and mental health. Older maternal age and caesarean delivery are associated with severe maternal morbidity in both current and future pregnancies. Antibiotic prescription for pregnant or postpartum women with suspected infection does not necessarily prevent progression to severe sepsis, which may be rapidly progressive. Delay in delivery, of up to 48 hours, may be safely undertaken in women with HELLP syndrome in whom there is no fetal compromise. Uterine compression sutures are a cost-effective second-line therapy for PPH. Medical comorbidities are associated with a fivefold increase in the odds of maternal death from direct pregnancy complications. External reviews identified more specific clinical messages for care than local reviews. Experience-led commissioning may be used as a way to commission maternity services.

Limitations

This programme used observational studies, some with limited sample size, and the possibility of uncontrolled confounding cannot be excluded.

Conclusions

Implementation of the findings of this research could prevent both future severe pregnancy complications as well as improving the outcome of pregnancy for women. One of the clearest findings relates to the population of women with other medical and mental health problems in pregnancy and their risk of severe morbidity. Further research into models of pre-pregnancy, pregnancy and postnatal care is clearly needed.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Sepsis during pregnancy or the postpartum period

Sepsis is an important cause of maternal morbidity and mortality worldwide. Early recognition and timely treatment are the key to ensuring a favourable outcome. This article reviews recent literature about definitions, pathophysiology, incidence, diagnosis, management, treatment, prevention and outcome of sepsis during pregnancy and the postpartum period.

Sepsis in Pregnancy: Identification and Management

Sepsis accounts for up to 28% of all maternal deaths. Prompt, appropriate treatment improves maternal and fetal morbidity and mortality. To date, there are no validated tools for identification of sepsis in pregnant women, and tools used in the general population tend to overestimate mortality. Once identified, management of pregnancy-associated sepsis is goal-directed, but because of the lack of studies of sepsis management in pregnancy, it must be assumed that modifications need to be made on the basis of the physiologic changes of pregnancy. Key to management is early fluid resuscitation and early initiation of appropriate antimicrobial therapy directed toward the likely source of infection or, if the source is unknown, empiric broad-spectrum therapy. Efforts directed at identifying the source of infection and appropriate source control measures are critical. Development of an illness severity scoring system and treatment algorithms validated in pregnant women needs to be a research priority.

Sepsis and pregnancy: do we know how to treat this situation?

Sepsis is defined as an acute inflammatory response syndrome secondary to an infectious focus. It has a high incidence, morbidity and mortality, causing substantial financial costs, especially due to complications such as septic shock and multiple organ dysfunction. The pathogen toxins associated with individual susceptibility culminate with cytokine release, which promotes a systemic inflammatory response that can progress to multiple organ dysfunction and eventual patient death.

Specifically, sepsis incidence, morbidity and mortality are lower in pregnant women, as this group is typically younger with fewer comorbidities having a polymicrobial etiology resulting in sepsis.

Pregnant women exhibit physiological characteristics that may confer specific clinical presentation and laboratory patterns during the sepsis course. Thus, a better understanding of these changes is critical for better identification and management of these patients. The presence of a fetus also requires unique approaches in a pregnant woman with sepsis.

Sepsis treatment is based on certain guidelines that were established after major clinical trials, which, unfortunately, all classified pregnancy as a exclusion criteria.

Thus, the treatment of sepsis in the general population has been extrapolated to the pregnant population, with the following main goals: maintenance of tissue perfusion with fluid replacement and vasoactive drugs (initial resuscitation), adequate oxygenation, control of the infection source and an early start of antibiotic therapy, corticosteroid infusion and blood transfusion when properly indicated, prophylaxis, and specifically monitoring and maintenance of fetal heath.

Pregnancy-Associated Severe Sepsis: Contemporary State and Future Challenges

Pregnancy is associated with an increased risk of infection related to its associated mechanical and physiological changes. Sepsis remains among the top causes of maternal death worldwide and is associated with substantial maternal morbidity. However, there are sparse data on pregnancy-associated severe sepsis (PASS), related in part to infrequent reports, varying case definitions and methodological approach, small cohort size, and often limited focus on severe sepsis in selected phases of pregnancy outcomes. Available reports vary, but indicate that PASS is a rare but likely increasing complication, and it is more likely to develop with increased maternal age, among minority women, the poor, those lacking health insurance, those with chronic illness or pregnancy-associated complications, and following invasive procedures. Obstetric sites of infection are the most prevalent, but non-obstetric infections often underlie pregnancy-associated severe sepsis, though the source of infection is often not readily apparent during initial care. Women with PASS can have a rapidly fatal course and require heightened clinician vigilance for early diagnosis and timely effective intervention. Nevertheless, available reports raise concerns about prevalent substandard care of these patients, contributing to adverse outcomes. The case fatality of PASS appears lower than that in the general population with severe sepsis, while the long-term outcomes of survivors remain unknown.

The Sepsis in Obstetrics Score: a model to identify risk of morbidity from sepsis in pregnancy

OBJECTIVE

We sought to design an emergency department sepsis scoring system to identify risk of intensive care unit (ICU) admission in pregnant and postpartum women.

STUDY DESIGN

The Sepsis in Obstetrics Score (S.O.S.) was created by modifying validated scoring systems in accordance with recognized physiologic changes of pregnancy. The S.O.S. was applied to a retrospective cohort of pregnant and postpartum patients from February 2009 through May 2011 with clinical suspicion of sepsis. The primary outcome was ICU admission. Secondary outcomes were telemetry unit admission, length of stay, positive blood cultures, positive influenza swabs, perinatal outcome, and maternal mortality. Receiver operating characteristic curves were constructed to estimate the optimal score for identification of risk of ICU admission.

RESULTS

In all, 850 eligible women were included. There were 9 ICU (1.1%) and 32 telemetry (3.8%) admissions, and no maternal deaths. The S.O.S. had an area under the curve of 0.97 for ICU admission. An S.O.S. ≥6 (maximum score 28) had an area under the curve of 0.92 with sensitivity of 88.9%, specificity of 95.2%, positive predictive value of 16.7%, and negative predictive value of 99.9% for ICU admission, with an adjusted odds ratio of 109 (95% confidence interval, 18-661). An S.O.S. ≥6 was independently associated with increased ICU or telemetry unit admissions, positive blood cultures, and fetal tachycardia.

CONCLUSION

A sepsis scoring system designed specifically for an obstetric population appears to reliably identify patients at high risk for admission to the ICU. Prospective validation is warranted.

Severe maternal sepsis in the UK, 2011-2012: a national case-control study

BACKGROUND

In light of increasing rates and severity of sepsis worldwide, this study aimed to estimate the incidence of, and describe the causative organisms, sources of infection, and risk factors for, severe maternal sepsis in the UK.

METHODS AND FINDINGS

A prospective case-control study included 365 confirmed cases of severe maternal sepsis and 757 controls from all UK obstetrician-led maternity units from June 1, 2011, to May 31, 2012. Incidence of severe sepsis was 4.7 (95% CI 4.2-5.2) per 10,000 maternities; 71 (19.5%) women developed septic shock; and five (1.4%) women died. Genital tract infection (31.0%) and the organism Escherichia coli (21.1%) were most common. Women had significantly increased adjusted odds ratios (aORs) of severe sepsis if they were black or other ethnic minority (aOR = 1.82; 95% CI 1.82-2.51), were primiparous (aOR = 1.60; 95% CI 1.17-2.20), had a pre-existing medical problem (aOR = 1.40; 95% CI 1.01-1.94), had febrile illness or were taking antibiotics in the 2 wk prior to presentation (aOR = 12.07; 95% CI 8.11-17.97), or had an operative vaginal delivery (aOR = 2.49; 95% CI 1.32-4.70), pre-labour cesarean (aOR = 3.83; 95% CI 2.24-6.56), or cesarean after labour onset (aOR = 8.06; 95% CI 4.65-13.97). Median time between delivery and sepsis was 3 d (interquartile range = 1-7 d). Multiple pregnancy (aOR = 5.75; 95% CI 1.54-21.45) and infection with group A streptococcus (aOR = 4.84; 2.17-10.78) were associated with progression to septic shock; for 16 (50%) women with a group A streptococcal infection there was <2 h-and for 24 (75%) women, <9 h-between the first sign of systemic inflammatory response syndrome and a diagnosis of severe sepsis. A limitation of this study was the proportion of women with sepsis without an identified organism or infection source (16.4%).

CONCLUSIONS

For each maternal sepsis death, approximately 50 women have life-threatening morbidity from sepsis. Follow-up to ensure infection is eradicated is important. The rapid progression to severe sepsis highlights the importance of following the international Surviving Sepsis Campaign guideline of early administration of high-dose intravenous antibiotics within 1 h of admission to hospital for anyone with suspected sepsis. Signs of severe sepsis in peripartum women, particularly with confirmed or suspected group A streptococcal infection, should be regarded as an obstetric emergency. Please see later in the article for the Editors' Summary.

Sepsis and maternal mortality

PURPOSE OF REVIEW

Despite global progress towards reducing maternal mortality, sepsis remains a leading cause of preventable maternal death. This review focuses on current measurement challenges, trends, causes and efforts to curb maternal death from sepsis in high and low-income countries.

RECENT FINDINGS

Under-reporting using routine registration data, compounded by misclassification and unreported deaths, results in significant underestimation of the burden of maternal death from sepsis. In the UK and the Netherlands the recent increase in maternal death from sepsis is mainly attributed to an increase in invasive group A streptococcal infections. Susceptibility to infection may be complicated by modulation of maternal immune response and increasing rates of risk factors such as caesarean section and obesity. Failure to recognize severity of infection is a major universal risk factor. Standardized Surviving Sepsis Campaign (SSC) recommendations for management of severe maternal sepsis are continuing to be implemented worldwide; however, outcomes differ according to models of intensive care resourcing and use.

SUMMARY

The need for robust data with subsequent analyses is apparent. This will significantly increase our understanding of risk factors and their causal pathways, which are critical to informing effective treatment strategies in consideration of resource availability.

The continuum of maternal sepsis severity: incidence and risk factors in a population-based cohort study

OBJECTIVE

To investigate the incidence and risk factors associated with uncomplicated maternal sepsis and progression to severe sepsis in a large population-based birth cohort.

METHODS

This retrospective cohort study used linked hospital discharge and vital statistics records data for 1,622,474 live births in California during 2005-2007. Demographic and clinical factors were adjusted using multivariable logistic regression with robust standard errors.

RESULTS

1598 mothers developed sepsis; incidence of all sepsis was 10 per 10,000 live births (95% CI = 9.4-10.3). Women had significantly increased adjusted odds (aOR) of developing sepsis if they were older (25-34 years: aOR = 1.29; ≥35 years: aOR = 1.41), had ≤high-school education (aOR = 1.63), public/no-insurance (aOR = 1.22) or a cesarean section (primary: aOR = 1.99; repeat: aOR = 1.25). 791 women progressed to severe sepsis; incidence of severe sepsis was 4.9 per 10,000 live births (95% CI = 4.5-5.2). Women had significantly increased adjusted odds of progressing to severe sepsis if they were Black (aOR = 2.09), Asian (aOR = 1.59), Hispanic (aOR = 1.42), had public/no-insurance (aOR = 1.52), delivered in hospitals with <1,000 births/year (aOR = 1.93), were primiparous (aOR = 2.03), had a multiple birth (aOR = 3.5), diabetes (aOR = 1.47), or chronic hypertension (aOR = 8.51). Preeclampsia and postpartum hemorrhage were also significantly associated with progression to severe sepsis (aOR = 3.72; aOR = 4.18). For every cumulative factor, risk of uncomplicated sepsis increased by 25% (95% CI = 17.4-32.3) and risk of progression to severe sepsis/septic shock increased by 57% (95% CI = 40.8-74.4).

CONCLUSIONS

The rate of severe sepsis was approximately twice the 1991-2003 national estimate. Risk factors identified are relevant to obstetric practice given their cumulative risk effect and the apparent increase in severe sepsis incidence.

Maternal sepsis: a Scottish population-based case-control study

OBJECTIVE

To describe the risk of maternal sepsis associated with obesity and other understudied risk factors such as operative vaginal delivery.

DESIGN

Population-based, case-control study.

SETTING

North NHS region of Scotland.

POPULATION

All cases of pregnant, intrapartum and postpartum women with International Classification of Disease-9 codes for sepsis or severe sepsis recorded in the Aberdeen Maternal and Neonatal Databank (AMND) from 1986 to 2009. Four controls per case selected from the AMND were frequency matched on year-of-delivery.

METHODS

Cases and controls were compared; significant variables from univariable regression were adjusted in a multivariable logistic regression model.

MAIN OUTCOME MEASURES

Dependent variables were uncomplicated sepsis or severe ('near-miss') sepsis. Independent variables were demographic, medical and clinical delivery characteristics. Unadjusted and adjusted odds ratios (OR) with 95% confidence intervals (95% CI) are reported.

RESULTS

Controlling for mode of delivery and demographic and clinical factors, obese women had twice the odds of uncomplicated sepsis (OR 2.12; 95% CI 1.14-3.89) compared with women of normal weight. Age <25 years (OR 5.15; 95% CI 2.43-10.90) and operative vaginal delivery (OR 2.20; 95% CI 1.02-4.87) were also significant predictors of sepsis. Known risk factors for maternal sepsis were also significant in this study (OR for uncomplicated and severe sepsis respectively): multiparity (OR 6.29, 12.04), anaemia (OR 3.43, 18.49), labour induction (OR 3.92 severe only), caesarean section (OR 3.23, 13.35), and preterm birth (OR 2.46 uncomplicated only).

CONCLUSIONS

Obesity, operative vaginal delivery and age <25 years are significant risk factors for sepsis and should be considered in clinical obstetric care.

The critically ill obstetric patient - Recent concepts

Obstetric patients admitted to an Intensive Care Unit (ICU) present a challenge to an intensivist because of normal physiological changes associated with pregnancy and puerperium, the specific medical diseases peculiar to pregnancy and the need to take care of both the mother and the foetus. Most common causes of admission to an ICU for obstetric patients are eclampsia, severe preeclampsia, haemorrhage, congenital and valvular heart disease, septic abortions, severe anemia, cardiomyopathy and non-obstetric sepsis. The purpose of this review is to present the recent concepts in critical care management of obstetric patients with special focus mainly on ventilatory strategies, treatment of shock and nutrition. The details regarding management of individual diseases would not be discussed as these would be beyond the purview of this article. In addition, some specific issues of importance while managing such patients would also be highlighted.

Management of the unconscious pregnant patient

The management of the unconscious pregnant patient encompasses many aspects of obstetrics and critical care. It is not uncommon to have to manage such a patient, therefore one needs to be well prepared. There is a spectrum of altered consciousness, brain death being the most extreme. The causes of unconsciousness can be general or pregnancy specific. It is important to consider the physiological changes in pregnancy when managing these patients. The immediate resuscitative measures are mostly the same as for the nonpregnant with a few modifications. It is important to remember that there are two patients involved and this can complicate management issues. A multidisciplinary approach would be prudent. The intermediate and long-term management should also involve the family. The issues of perimortem and somatic support for foetal maturity are also discussed.