Critically ill obstetric patients present a unique challenge to the obstetrician, anesthesiologist and intensivists. Maternal mortality
has shown a sharp decline in the developed countries but in developing countries it is still high due to lack of good maternal antenatal
services and obstetric intensive care. The indications for admission of a parturient to an ICU are obstetric complications as well as non
obstetric indications. Optimal management of the critically ill obstetric patient involves early detection and multi disciplinary approach
with close collaboration of the critical care team including obstetricians, midwives, anesthesiologists and neonatologists based on
knowledge of physiological and pharmacological alterations. This article aims to provide a comprehensive review for the management
of critically ill obstetric patient including monitoring, ventilator strategies, drugs, nutrition, thromboprophylaxis, prognostic indicators
and recent update on commonly encountered situations.
Critical Illness, Obstetric, ICU
Critical illness in the parturient presents a unique challenge to the
obstetrician, anesthesiologist and intensivists. Complications
can occur any time during pregnancy and puerperium which may
progress to severe maternal morbidity also known as ‘near-miss’
maternal mortality, thus necessitating critical care support. The
medical management of the critically ill obstetric patient requires
a complete knowledge of the altered physiology of pregnancy as
well as the superimposed acute pathological insult, demanding
management by a multidisciplinary team including obstetrician,
intensivists and anesthesiologists.
The incidence of ICU admission of an obstetric patient in developed
countries is 2-4/1000 deliveries, while in developing countries
the incidence is 2-13.5/1000 deliveries. Maternal mortality
has shown a sharp decline in the developed countries but in developing
countries it is still high due to lack of good maternal antenatal
services and obstetric intensive care. The anesthesiologist
plays a key role in the management of high risk pregnancies, as
they are trained in advanced life support and resuscitation and they
should educate the medical and paramedical staff involved in the
labor ward for the early recognition, monitoring and treatment of
Indications for ICU admission
The reasons for obstetric admissions to an ICU include obstetric
(47%-93%) as well as non obstetric indications.
Antepartum and postpartum hemorrhage,
hypertensive disease like preeclampsia and eclampsia, puerperal
sepsis are the most frequent indications.
Non obstetric indication:
maternal cardiac disease, trauma, anesthetic
complications, cerebrovascular accidents, malaria, viral
hepatitis, cerebral venous thrombosis, poisoning and drug overdose.
Presence of other co morbidities like diabetes and renal diseases
also contribute negatively to maternal outcome in the ICU, and
hence simultaneous stabilization of mother and fetus should be our
Altered Physiology in Pregnancy Relevant to Criticality
Almost all organ systems are affected by the physiological changes
that occur during pregnancy; however cardiovascular and the
respiratory systems are the most important systems that affect criticality in the obstetric patient.
The blood volume is increased by 50%
during pregnancy but plasma volume increases much more as
compared to the corpuscular volume which causes physiological
anemia. The Heart rate and cardiac output increases while
Systemic and Pulmonary vascular resistance is decreased. In Preeclampsia
and Eclampsia, patients have relative haemoconcentration and thus are much more susceptible to blood loss during
delivery. These patients are more prone to pulmonary edema due
to increased vascular permeability and decreased colloid osmotic
pressure. After 20 weeks gestation they are prone to supine hypo-tension
syndrome due to the pressure of the gravid uterus on the
descending aorta and inferior vena cava which is relieved in the
lateral position or on displacement of the uterus.
Minute volume is increased due to increased
tidal volume and respiratory rate leading to respiratory alkalosis
with decrease in serum bicarbonate levels to compensate this alkalosis.
During pregnancy Residual volume, functional residual
capacity and total lung capacity are decreased so pregnant patients
are more prone to hypoxia.
Total leukocyte count may increase up-to
25000/mm3 which may lead to misdiagnoses of infection in ICU.
Platelet counts may decrease but coagulation process is deranged
with increased levels of almost all pro coagulants and decrease in
fibrinolysis leading to increased incidence of DVT and pulmonary
Renal plasma flow and GFR are increased while
serum creatinine is decreased from 1.2 to 0.8 mg/ dl.
Specific Obstetric Emergencies
Massive obstetric hemorrhage is defined
as blood loss >1500 ml, a decrease in Hb of <4 g/dl. It is
responsible for more than 30% of all maternal deaths in low income
countries and over 10% of maternal deaths in high income
countries. The management involves treatment of uterine stony
(uterine massage, oxytocin, and prostaglandin analogues), surgical
intervention (uterine tamponade or compression packing, balloon
compression sutures), arterial ligation and selective radiological
embolization and even hysterectomy. The goal directed resuscitation
strategy using point of care coagulation tests (thromboelastography
and rotational thromboelastometry) is considered important
for optimal management. Use of PRBC, FFP and platelets according
to massive transfusion protocols with early use of fibrinogen
concentrates and tranexamic acid is life saving.
The complications of severe preeclampsia include
HELLP syndrome, pulmonary edema, renal failure, Cerebrovascular
accidents and Eclampsia which results in ICU admission.
Management includes control of hypertension and seizure, restricted
fluid administration to avoid pulmonary edema and early
delivery of the fetus.
Maternal sepsis causes 15% of maternal death worldwide.
Puerperal sepsis and UTI are the most important causes of sepsis
in developed nations but Malaria, HIV and community acquired
pneumonia are important causes in developing countries. Adequate
volume expansion to optimize cardiac output, antibiotic
regimens to treat gram negative, gram positive and anaerobic infections
along with invasive haemodynamic monitoring to guide
inotropic therapy is indicated as per the recent guidelines of surviving
Amniotic fluid embolism (AFE):
AFE is a clinical diagnosis
of exclusion and has a high mortality rate. The biomarkers used
for diagnosis include Zinc corproporphyrin-1, Sialyl Tn antigen
(STN), Complement C-3, C-4, interlukin-8, insulin- like growth
factor-binding protein-1. The management of AFE is mainly supportive
and should be managed in an ICU by a multidisciplinary
Cardiac disorders affect 1-3% pregnant women
and account for 10-15% Maternal Mortality. Peripartum cardiac
disease in pregnancy range from congenital anomalies to valvular
heart disease, myocardial infarction, dilated cardiomyopathy
and pulmonary hypertension which is further worsened by the
high cardiac output during pregnancy. The management strategy of
shock in such cases includes volume replenishment, appropriate
antibiotics, vasopressors, early revascularization, inotropic support
and even mechanical circulatory support for refractory cases.
 Severe Mitral stenos-is may present with pulmonary edema and
atrial fibrillation while Aortic stenos is may develop fatal arrhythmia
and refractory heart failure. AHA recommends beta blockers,
nondihydropyridine, calcium channel blockers and digoxin for AF
in pregnancy. Uteronic drugs should be used cautiously at the lowest
effective dose and never as a bolus. Echocardiography should
be used as a point of care in these patients.
The patient positioning and role of perimortem
caesarean delivery are two main problems during CPR in
pregnant patient. Left lateral tilt decreases-chest compression quality
hence manual uterine displacement by another care provider can
relieve allocator compression. If, gestational age is 20 weeks then
perimortem caesarean delivery should be considered as it would
relieve allocator compression.
Critically ill obstetric patients are managed by a multidisciplinary
approach with active involvement of intensivists, obstetricians,
nurses, paediatricians, physiotherapists and pharmacists. Maternal
haemodynamic optimization requires application of basic intensive
care principles with modifications based on physiological
changes during pregnancy.
Parturients should be admitted in the ICU if two organ
systems are compromised with a need for ventilatory support.
Foetal monitoring must be performed after 24 weeks of gestation
to help in determining the adequacy of maternal cardiorespiratory
and metabolic parameters. Invasive monitoring may be required
in some patients along with minimum mandatory monitoring. The
choice of invasive monitoring like central venous pressure (CVP),
pulmonary artery (PA) catheter for pulmonary capillary wedge
pressure (PCWP), systemic vascular resistance, cardiac output, PA
pressure and mixed venous oxygen saturation will depend on the
criticality of the ICU patients.
Noninvasive positive pressure ventilation
(NIPPV) has been shown to benefit a subset of patients with obstructive
airway diseases, as well as sleep disordered breathing in
pregnancy but can lead to higher risk for aspiration. A low threshold
for ETT intubation should be kept in view of high risk for aspiration.
Standard protocols for initiation of ventilation in parturients
should be in accordance to the physiological changes in the respiratory
parameters during pregnancy. Smaller size ETT is required
due to airway edema which otherwise increases airway resistance
and interferes with successful weaning during prolonged ventilation.
When conventional methods of ventilation fail, newer modes-such as Airway Pressure Release Ventilation (APRV) and high
frequency oscillatory ventilation (HFOV) have been tried.
Extra-corporeal membrane oxygenation (ECMO) should be used
early in acute respiratory failure with refractory hypoxemia. Major
disadvantage of ECMO is that it exposes the indwelling foetus to
extra-corporeal circulation and systemic heparinisation and bleeding
in the mother.
Commonly used antimicrobials such as penicillin, cephalosporin,
macrolides and acyclovir fall into category A, whereas
aminoglycosides, quinolones, vancomycin and amphotericin fall
in category C. Parturients have high incidence of vaginal candidiasis
because of increased secretion of sex hormones. Topical
azoles should be the first line in the first trimester. There is a raised
concern regarding oral fluconazole (category D) being associated
with an increased risk of spontaneous abortions and stillbirths in
addition to its teratogenicity in high dosage.
Enteral nutrition is considered the optimal method for
providing nutrition compared to parenteral nutrition. Aspiration
risk can be minimized with anti-aspiration prophylaxis (H2 blockers
or proton pump inhibitors), pro-kinetic drugs, using semi recumbent
position for administering enteral feeds and routine radiological
confirmation of the nasogastric tube position. The basal caloric
requirement of a critically ill patient is 25 kcal/kg/day (ideal body
weight) that turns out to be 2200 to 2800 kcal/day for an average
Parturient needs additional 340 kcal/day and 452
kcal/day in the second and third trimesters, respectively. The protein
requirement is twice that of a non obstetric patient. Carbohydrates
meet up to 70% caloric requirements while fats meet 30%
caloric requirements. Proteins in diet compensate for negative nitrogen
balance and hence are not included in the caloric needs of
the critically ill patient. An optimal nutritional solution needs to
have additional amounts of zinc, folate and vitamin B12 in the
first trimester. The iron content needs to be almost double that of
non obstetric population, corresponding to 4–6 mg/day.
Obstetric critically ill patients have four
times higher risk of developing deep vein thrombosis compared to
other critically ill patients. Patients admitted in ICU must be started
on thromboprophylaxis (if there are no other contraindications)
as soon as possible. Pharmacological thromboprophylaxis can be
achieved with both unfractionated and low molecular weight heparins
such as enoxaparin, dalteparin and tinzaparin. However, in
case of heparin induced thrombocytopenia (HIT) or severe allergic
reactions, a feasible alternative could be provided by argatroban,
danaparoid, fondaparinux or lepirudin.
In developed countries mortality rate in obstetric patients ranges
from 12-20% with an admission rate of 3% of overall ICU admissions
while in India mortality rate ranges from 28-60% and
the admission rate to the ICU is 7%. These patients have a better
prognosis because delivery will often improve their physiological
Different scoring systems are validated for critically ill non obstetric
patients which are either based on physiological variables
[Acute Physiology and Chronic Health Evaluation (APACHE) II,
Simplified Acute Physiology Score (SAPS) II] or based on organ
failure [Sequential Organ Failure Assessment (SOFA), and Multiple
Organ Dysfunction Score (MODS)]. Physiology based scores
are not very reliable as normal physiological changes of pregnancy
make the parameters fall into an abnormal range altering these
scores. Sepsis in Obstetrics Score (SOS) that includes parameters
like temperature, heart rate, respiratory rate, oxygen saturation,
leukocyte count and lactic acid has recently been developed which
determines predictability of ICU admission from emergency department
(ED). However, organ failure based scores such as
MODS have been found to be superior to SOS in mortality prediction
in the obstetric patients.
Modified Early Warning Scores
MOEWS(Modified Early Warning Scores) is an important indicator
for impending critical illness in the obstetric wards, which includes
physiological parameters such as respiratory rate, heart rate,
blood pressure, temperature, mental status and urine output into the
scoring systems. These physiological measurements are incorporated
into a scoring system and once a trigger score is reached the
patient is referred to the high dependency or intensive care unit.
Generally it is observed that Obstetric patients admitted to the ICU
have a lower mortality rate than general medical patients. 
Optimal management of the critically ill obstetric patient involve
early detection and multi disciplinary approach with close collaboration
of the critical care team including obstetricians, midwives,
anesthesiologists and neonatologists based on knowledge of physiological
and pharmacological alterations. Thus management of
obstetric complications in a dedicated HDU or obstetric ICU can
improve both maternal and foetal outcome, especially in less resourced
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