Obstetric Critical Care Masterclass

Clinical overview

Obstetric critical care begins before admission to an intensive care unit. It begins when a clinician recognises that a pregnant or recently pregnant patient is using physiological reserve to conceal organ dysfunction, names the life threat, starts effective support and mobilises the right people before deterioration becomes cardiac arrest. The scope runs from early pregnancy to the puerperium and includes deterioration on an antenatal ward, collapse in theatre, respiratory failure in a medical unit, haemorrhage in a district hospital, complex heart disease in a tertiary centre and recovery after ICU.

The organising principle is maternal physiology first, with fetal and delivery decisions integrated into maternal resuscitation. Maternal oxygenation, circulation and source control usually provide the best fetal resuscitation. Fetal monitoring is valuable when it changes a safe obstetric decision; it must never delay airway management, chest compressions, haemorrhage control, antimicrobials or transfer. Delivery may remove a septic or haemorrhagic source, terminate hypertensive disease, relieve aortocaval compression or make cardiopulmonary support feasible. It may also impose anaesthesia, blood loss, autotransfusion and abrupt haemodynamic change. Therefore “deliver” is not a generic response to critical illness: it is a source-control or resuscitation decision made against a defined maternal mechanism.

This masterclass converts general adult ICU physiology into obstetric practice. It covers monitoring, access, airway management, respiratory and circulatory support, shock, transfusion, sepsis, cardiac and thromboembolic emergencies, acid–base disorders, kidney injury, neurological disease, abdominal and endocrine emergencies, toxicology, sedation, nutrition and recovery. It does not credential an obstetrician to perform specialist anaesthetic, critical-care, echocardiographic, interventional or ECMO procedures. It teaches what the registrar must recognise, initiate, communicate and reassess, and when expert help or referral is no longer optional.

Most organ-support trials exclude pregnancy. The correct response is neither to deny a pregnant patient proven critical care nor to pretend that extrapolation is obstetric evidence. State the evidence boundary, preserve the physiology, account for pregnancy and the postpartum period, and seek multidisciplinary judgement where maternal and fetal effects compete.

Core knowledge

The recognition-to-recovery map

Critical care is a continuous pathway rather than an ICU room:

1. Recognise: detect abnormal trends, new oxygen need, altered consciousness, oliguria, haemorrhage, escalating pain, fever with organ dysfunction or a clinician’s sense that the patient is deteriorating.
2. Resuscitate: perform ABCDE in parallel, relieve aortocaval compression where relevant, treat immediately reversible threats and measure the response.
3. Phenotype: define the dominant physiology—hypoxaemic or ventilatory respiratory failure; hypovolaemic, distributive, cardiogenic, obstructive or mixed shock; neurological emergency; metabolic or toxic collapse.
4. Control the cause: stop bleeding, drain infection, evacuate retained or infected uterine contents, treat eclampsia, reperfuse selected pulmonary embolism or coronary occlusion, relieve obstruction and decide whether delivery changes the maternal disease.
5. Support organs: provide oxygen, ventilation, vasoactive support, transfusion, renal support, seizure control, nutrition and thromboprophylaxis at the level the patient requires.
6. Reassess: repeat physiology after every intervention. An intervention without a response and stop rule is an unmonitored experiment.
7. Recover: liberate support, prevent secondary harm, restore mobility and nutrition, support lactation and family contact, address psychological injury and hand over future-pregnancy risks.

Oxygen delivery is the common currency

Shock, anaemia, hypoxaemia and pump failure converge on inadequate cellular oxygen delivery. Conceptually:

$\text{oxygen delivery} = \text{cardiac output} \times \text{arterial oxygen content}$

Arterial oxygen content is dominated by haemoglobin-bound oxygen, not dissolved oxygen. This explains why a saturation of 100% does not compensate for profound anaemia, why crystalloid can worsen oxygen delivery by diluting haemoglobin, why a normal blood pressure does not prove adequate flow and why a failing ventricle may not tolerate the fluid that would help a patient with haemorrhage. The bedside task is to identify which component is failing—oxygenation, haemoglobin, flow or distribution—and correct that component while controlling the cause.

Pregnancy changes the baseline but not this logic. Cardiac output and plasma volume rise, systemic vascular resistance falls, oxygen consumption increases and functional residual capacity falls. Glomerular filtration increases and serum creatinine is normally lower. Minute ventilation increases, producing a chronic compensated respiratory alkalosis. Fibrinogen rises and the haemostatic system becomes prothrombotic. A young patient can maintain blood pressure despite substantial blood loss, then deteriorate quickly when reserve is exhausted. The postpartum circulation can change abruptly as uterine blood flow returns centrally, aortocaval compression resolves and extracellular fluid mobilises.

Organ support is indication-based

Each support has a purpose, a burden and a stopping condition:

“More support” is not automatically better. The correct dose is the least support that achieves a defined physiological goal while definitive treatment takes effect.

The South African level-of-care model

The same physiology presents in very different systems. A labour ward may provide continuous observation and immediate obstetric source control but no invasive ventilation. Obstetric high care may provide one-to-one nursing, arterial monitoring and limited vasoactive or non-invasive support. A general ICU may provide multi-organ support but need obstetric input brought to the bedside. A tertiary or quaternary centre may add interventional radiology, advanced cardiology, neurosurgery or ECMO.

Level of care is determined by the support the patient needs, not by a label. The clinician at a district or regional facility must begin treatment with available resources, communicate clinician-to-clinician, define what the receiving centre will add and plan a monitored transfer. “Awaiting an ICU bed” is not a management plan. During delay, allocate a responsible senior clinician, monitoring frequency, airway plan, vasoactive and blood-product plan, trigger for renewed escalation and transport readiness.

The curriculum

The modules are deliberately linked because organ failure does not respect chapter boundaries:

• M1 — Recognition, pregnancy physiology, triage and ICU systems
• M2 — Vascular access, haemodynamic monitoring and point-of-care ultrasound
• M3 — The obstetric airway, oxygenation and capnography
• M4 — Respiratory support, ventilation, ARDS, proning, VAP and ECMO
• M5 — Fluids, responsiveness, vasopressors and haemodynamic targets
• M6 — Shock phenotyping and simultaneous resuscitation
• M7 — Major obstetric haemorrhage, transfusion and coagulopathy
• M8 — Fever, maternal sepsis, antimicrobials and source control
• M9 — Cardiac critical care, dysrhythmias, acute coronary syndromes and arrest
• M10 — VTE, pulmonary embolism and amniotic-fluid embolism
• M11 — ABG, acid–base disorders, lactate and ketoacidosis
• M12 — AKI, electrolytes and kidney support
• M13 — Altered consciousness, eclampsia, movement disorders, stroke and trauma
• M14 — Liver failure, pancreatitis and abdominal or urinary emergencies
• M15 — Endocrine crises, overdose and poisoning
• M16 — Analgesia, sedation, prophylaxis and critical-care nutrition
• M17 — Liberation, postpartum recovery, rehabilitation and transfer from ICU
• M18 — Setting up the ventilator: modes, first settings and safety limits
• M19 — PEEP, oxygenation and permissive hypercapnia in pregnancy
• M20 — Reading the ventilator: waveforms, trigger, flow and dyssynchrony
• M21 — Troubleshooting the ventilated obstetric patient
• M22 — Weaning in practice, extubation and prolonged respiratory failure

Modules 18 to 22 are the ventilator sequence: how to set the machine up, how to decide oxygenation and carbon-dioxide targets in pregnancy, how to read what the waveforms are telling you, what to do when the patient deteriorates at three in the morning, and how to get her off it again.

Assessment

The first ten minutes

At the bedside, separate immediate action from diagnostic refinement.

Recognise severity. Ask whether the patient can maintain her airway, oxygenation, ventilation, circulation and consciousness without escalating support. Look for rapidly increasing oxygen requirement, exhaustion, inability to speak, cyanosis, shock, active major haemorrhage, new confusion, seizure, focal neurology, oliguria, severe metabolic derangement or a rising lactate. Call for senior obstetric and anaesthetic/critical-care help early.

Establish context. Record gestation or postpartum day, reason for admission, comorbid disease, medicines, allergies, HIV/TB context where relevant, recent anaesthesia or procedure, bleeding and fluid balance. Determine whether the uterine size can cause aortocaval compression. Ask whether delivery, evacuation or surgery could be source control.

Perform simultaneous ABCDE. Assign team members rather than allowing one clinician to complete each letter serially. Attach ECG, non-invasive blood pressure and pulse oximetry; measure respiratory rate manually; establish intravenous access; check glucose; obtain gas, lactate, full blood count, electrolytes, creatinine, liver tests and coagulation/fibrinogen when indicated. Order cultures and imaging without delaying emergency treatment.

Name the syndrome and phenotype. “Unwell postpartum patient” is not enough. A useful problem representation is: “Postpartum day three, febrile, confused, lactate 4.2 mmol/L, hypotensive after a small reassessed fluid challenge, hyperdynamic left ventricle and no pulmonary congestion—probable septic shock from a pelvic source.” This statement identifies severity, physiology, likely cause and next action.

Serial assessment

One observation is a photograph; critical illness is a film. Chart the direction and rate of change in respiratory rate, oxygen requirement, heart rate, blood pressure, mental state, temperature, urine output, bleeding, lactate, acid–base status, platelets, creatinine and liver enzymes. Pregnancy-adjusted early-warning systems organise observation but do not replace judgement. A score should trigger a response process; it should not be used as a diagnosis, a substitute for examination or a reason to ignore a clinician’s concern.

The organ-support inventory

During every review ask:

• What support is being given now?
• What is its physiological target?
• Is the target being met?
• What harm is accumulating?
• What definitive treatment is still pending?
• What would trigger escalation, transfer or de-escalation?

This prevents “set-and-forget” oxygen, fluid, vasopressors, ventilation and antibiotics.

Management

Team design

The initial leader states priorities and assigns roles: airway, compressions if needed, circulation/access, medication, haemorrhage/source control, obstetric procedure, fetal/neonatal care, documentation and communication with blood bank/theatre/referral centre. The leader uses closed-loop communication and announces changes in diagnosis or plan. A neonatal team, when relevant, should be separate from the team resuscitating the mother.

Critical-care consultation does not remove obstetric responsibility. The obstetrician identifies pregnancy-specific causes, evaluates the uterus and birth canal, decides whether delivery or evacuation contributes to source control, anticipates haemorrhage and maintains continuity with the patient and family. The intensivist or anaesthetist leads advanced airway and organ-support decisions. Both must understand the other discipline’s constraints.

Stabilisation before and during transfer

Transfer only after addressing threats that are likely to worsen en route. Secure an airway that is unlikely to remain safe; drain a tension pneumothorax; control accessible haemorrhage; begin blood, antimicrobial or antidote treatment; stabilise fractures and lines; ensure adequate oxygen and battery supply; prepare infusions with reserve volume; accompany the patient with a clinician who can manage foreseeable deterioration. Send a concise written and verbal handover with gestation/postpartum day, diagnosis, interventions and response, drugs and infusions, allergies, blood availability, fetal status when relevant, unresolved threats and the agreed receiving clinician.

When transfer is unsafe because an immediate procedure is the only path to survival, perform the life-saving intervention at the current location with remote specialist support where possible. The decision is a balance between the risk of local capability limits and the risk of deterioration during delay or transport.

Delivery during critical illness

Use a four-question test:

1. Is the pregnancy or uterus the cause or continuing source of deterioration?
2. Would delivery materially improve maternal physiology or permit definitive treatment?
3. Can the patient tolerate anaesthesia, surgery, haemorrhage and the postpartum shift now?
4. If delivery is deferred, what is the explicit trigger and how will fetal and maternal status be monitored?

In maternal cardiac arrest with a fundus at or above the umbilicus and no return of spontaneous circulation, resuscitative delivery is a maternal resuscitation manoeuvre: prepare at recognition, perform it at the arrest location and aim to complete delivery by five minutes. Outside arrest, timing and route are individualised. A non-reassuring fetal trace caused by maternal hypoxaemia or hypotension demands maternal correction; it does not automatically justify hazardous delivery into uncontrolled shock.

Daily critical-care review

Use a structured review that includes the cause, each failing organ, lines and devices, antimicrobial indication and stop/review date, analgesia and sedation target, delirium, mobilisation, VTE and stress-ulcer prophylaxis, nutrition, glucose, bowel and bladder care, skin and wound care, fetal/delivery plan, lactation, family communication, ceilings of treatment and readiness for liberation or transfer. Remove devices and therapies as soon as their indication ends.

Red flags / pitfalls

• Waiting for hypotension before calling the patient shocked. Tachypnoea, altered mentation, cool or mottled skin, oliguria, rising lactate and increasing oxygen need may precede a pressure fall.
• Treating the early-warning score rather than the patient. A score organises escalation; it cannot rule out a life-threatening diagnosis.
• Calling every low blood pressure hypovolaemia. Fluid can worsen cardiogenic failure, pre-eclamptic pulmonary oedema and right-heart obstruction.
• Making the fetus the first monitor during maternal collapse. Maternal resuscitation takes priority; fetal monitoring is removed during cardiac arrest.
• Using pregnancy to justify substandard organ support. Ventilation, vasopressors, dialysis, imaging, anticoagulation and antidotes are provided when indicated, with pregnancy-specific modification.
• Using delivery as a reflex. Delivery is beneficial when it removes a cause or improves physiology; it can destabilise a patient when the uterus is not the problem.
• Confusing ICU admission with critical care. Effective recognition and support begin wherever the patient deteriorates.
• Moving an unstable patient without a transport physiology plan. Equipment, escort, reserve oxygen, infusions and rescue actions must match the predicted risks.
• Failing to plan recovery. Delirium, weakness, trauma, lactation disruption, bereavement and future-pregnancy risk are clinical outcomes, not optional social details.

Evidence anchors

• Marino's The Little ICU Book, third edition (publisher record, 2025) — the complete 51-chapter general-ICU source framework used for this masterclass; concepts were rewritten and obstetrically adapted, while current sources below govern clinical recommendations.
• ACOG Practice Bulletin No. 211: Critical Care in Pregnancy, 2019; reaffirmed 2025 — explicitly recognises that much obstetric critical care is extrapolated from nonpregnant evidence.
• American Heart Association 2025 Guidelines, Part 10: Special Circumstances of Resuscitation — current pregnancy cardiac-arrest modifications and resuscitative-delivery recommendations.
• South African National Integrated Maternal and Perinatal Care Guideline, 2024 — national maternal-care and referral framework.
• South African Adult Hospital Level STG/EML, Chapter 6: Obstetrics, version 2.0, 26 March 2026 — operative national medicine guidance for obstetric emergencies.
• Surviving Sepsis Campaign Adult Guidelines, 2026 — current general organ-support guidance, applied with pregnancy-specific sources and limitations.