Obstetric early warning scores and escalation — structured SAQ (15 marks)

(a) Immediate assessment and investigations by domain (5 marks)

One mark per domain covered, with the investigations named. ^[5][6]

• ABCDE with obstetric modification: 15-degree left lateral tilt, high-flow oxygen, two large-bore cannulae, balanced crystalloid, compute the shock index (122/96 = 1.27 — significant loss or sepsis until proven otherwise).
• Sepsis domain: lactate (the bedside number that moves first — above 2 mmol/L is a sick obstetric patient, above 4 mmol/L is shock), blood cultures, urine culture, wound and vaginal swabs, FBC, CRP, coagulation, venous or arterial blood gas.
• Cardiopulmonary domain: ECG, troponin, NT-proBNP, chest X-ray (single PA film is below fetal-harm dose), bedside echo if cardiac failure on the differential.
• Haemorrhage domain: inspect the wound (the midwife documented ooze), FBC, coagulation with fibrinogen, crossmatch. Concealed retroperitoneal bleed is on the differential of a post-caesarean patient with tachycardia and hypotension.
• Source hunt: examine the wound, the uterus, the lochia, the chest, the urine, the calves (DVT). Plan a focused bedside ultrasound for free fluid.^[6]

Working diagnosis statement for the reasoning mark: "Multi-parameter deterioration with fever and tachypnoea — this is sepsis with possible wound infection until proven otherwise; haemorrhage and cardiopulmonary event are the parallel differentials." ^[5]

(b) MEWT severe single-value triggers, sustained (3 marks)

Reproduce verbatim, with the 20-minute rule and the rationale. ^[3][4]

• Maternal heart rate above 130 bpm.
• Respiratory rate above 30 per minute.
• Mean arterial pressure under 55 mmHg.
• Oxygen saturation under 90%.
• Altered mental status, or nurse concern.^[3][4]

The 20-minute rule: triggers must be sustained for more than 20 minutes (or two abnormal values in the non-severe band) — this is the design feature that filters transient physiology (post-epidural effect, anxiety, post-contraction tachycardia) from real deterioration.^[3]

Rationale: single sustained abnormal values are highly specific for serious pathology; the persistence requirement trades a small loss of sensitivity for a large gain in specificity, reducing alarm fatigue.^[4]

(c) Design principles and the two architectural families (4 marks)

One mark for each family with its validation study, and two marks for the cross-cutting principles. ^[1][3]

• Aggregate-weighted scoring (MEOWS): each parameter is assigned points for deviation from normal; points are summed; a total above a threshold triggers. Validation: Singh 2012 in 676 consecutive obstetric admissions — sensitivity 89% (95% CI 81–95%), specificity 79% (95% CI 76–82%), PPV 39% (95% CI 32–46%), NPV 98% (95% CI 96–99%). Strength is sensitivity (high NPV); weakness is the false-positive burden (low PPV).^[1]
• Single-parameter triggering (MEWT): one abnormal value (sustained) triggers, no summation. Validation: Shields 2016, which showed MEWT implementation across six hospitals reduced maternal morbidity, and Hedriana 2016, in which two or more persistent triggers for 30 minutes carried OR 61.7 (95% CI 13.2–288.0) for ICU admission.^[3][4]
• Cross-cutting principle 1: the chart must use pregnancy-specific thresholds — a HR of 95, a BP of 95/55 and a RR of 20 are normal late in pregnancy; the chart flags deviation from the pregnant baseline, not from the non-pregnant baseline.
• Cross-cutting principle 2: the chart is only useful paired with an escalation pathway. A documented trigger that is not acted on is the commonest failure mode in maternal mortality enquiries. Audit the chain (trigger → clinician → response → outcome), not the chart alone.^[5]

(d) Escalation pathway and disposition (3 marks)

One mark per tier named, with the disposition decision. ^[5][6]

• Tier 1: bedside review by the registrar within 10 minutes (already done); recheck the obs, send the focused investigations, document a working diagnosis and a time to re-review.^[5]
• Tier 2: senior obstetric and anaesthetic review within 30 minutes — this patient has a persistent multi-parameter trigger with fever; sepsis bundle activated: cultures, broad-spectrum antibiotics within the hour, balanced crystalloid, source control planning.^[5][6]
• Tier 3: transfer to HDU for ongoing single-organ support (intravenous antibiotics, fluid resuscitation, close nursing, magnesium if eclampsia develops); transfer to ICU if multi-organ failure evolves (ventilation, vasopressors, renal replacement therapy).^[6]

Disposition decision: this woman meets the criteria for HDU admission now — persistent multi-parameter trigger, fever, evolving sepsis, post-operative. Document the time of transfer, the team, and the safety-net for deterioration en route.^[5]