Fetal Monitoring & CTG Interpretation: NICE Case Study
Expert review of CTG interpretation, fetal physiology, and NICE guidelines using a clinical case study on maternal tachycardia and metabolic acidosis.
Clinical Case Review & CTG Interpretation
Data-driven Learning Incident (INC-151338) & NICE Guideline Refresher
Case Context: Patient Profile
Parity: P0 Gestation: 40+4 weeks BMI: 37 (Booking) Indication for IOL: Large for Gestational Age (LGA - 97th Centile)
Key Risk Factors: • Induction of Labour (Propess, CRB, Prostin) • Multiple Vaginal Checks (Risk of Infection) • Prolonged Maternal Tachycardia noted antenatally
Timeline: The Emerging Picture
Antenatal / Early Admission
Maternal tachycardia noted (100-115 bpm). ECG review normal. WCC raised but no CRP checked. Infection risk not fully ruled out.
18:00 (Active Labour)
CTG Baseline increases from 120 bpm to 140 bpm. Syntocinon in progress. This 20 bpm rise was a subtle sign of fetal stress/infection.
Critical Decision & Outcome
20:30 - Decision for Cat 2 CS
Failure to progress at 2cm. Syntocinon stopped. CTG baseline dropped to 125-130 bpm.
22:13 - Delivery (Forceps)
Difficult delivery (Wrigleys x2). Meconium liquor observed. 9 mins from 'Knife to Skin' to birth.
[Space reserved for user to attach 20:30 - 22:13 CTG Trace]
The Outcome: Cord Gases Analysis
Baby born in good condition (Apgars 8 at 1 min, 9 at 5 mins), but cord gases revealed significant metabolic acidosis likely exacerbated by difficult delivery.
Key Learning Points
Baseline Shift is Significant: An increase in baseline (e.g., 20bpm rise) even within 'normal' range can be a sign of developing hypoxia or infection.
Maternal Tachycardia Context: Persistent maternal tachycardia + multiple VEs should trigger a 'Rule Out Infection' protocol (CRP alongside WCC).
Holistic Review: Compare current CTG baseline with the *initial* monitoring baseline, not just the previous hour.
NICE Guidelines: CTG Feature Definitions
Baseline Rate
Normal: 110–160 bpm.<br>Stable excluding accels/decels.
Variability
Normal: 5–25 bpm.<br>Reflects CNS integrity & oxygenation.
Decelerations
Early: Concurrent with contraction (Head compression).<br>Variable: Rapid drop/recovery (Cord).<br>Late: Delayed (>50% after peak) (Placental insufficiency).
Accelerations
Rise of >15bpm for >15s.<br>Presence is reassuring of somatic nervous system function.
NICE Categorisation System
NORMAL
• All features reassuring • Baseline 110-160 • Variability 5-25 • No non-reassuring features
SUSPICIOUS
• 1 non-reassuring feature AND • 2 reassuring features • Action: Correct underlying causes, conservative measures.
PATHOLOGICAL
• 2 or more non-reassuring features OR • 1 abnormal feature • Action: Review by Senior/Consultant. Consider delivery/FBS.
Physiology: Why the Heart Rate Changes
• Chemoreceptors: Detect low O2 / high CO2 -> Stimulation of Vagus nerve -> Cardio-deceleration (Late Decels). • Baroreceptors: Detect high pressure (cord compression) -> Vagal response to lower BP -> Variable Decelerations. • Sympathetic Nervous System: Releases catecholamines to maintain Cardiac Output when stressed (Rising Baseline/Tachycardia).
Mapping Physiology to Action
Summary & Discussion
This case highlights the importance of recognizing rising baselines and maternal tachycardia as early warnings.
NICE guidelines categorize risk, but physiology explains 'why'. Understanding the mechanism drives the correct action.
Cord gases confirmed significant acidosis, validating the need for the intervention, though earlier recognition might have reduced the depth of acidosis.
- ctg-interpretation
- fetal-monitoring
- nice-guidelines
- obstetrics
- clinical-case-study
- maternity-safety
- midwifery-education