//fpnotebook.com/
Fetal Scalp pH
Aka: Fetal Scalp pH, Fetal Scalp Blood Sampling
- Indications
- Assess degree of Fetal Hypoxia
-
Scalp Stimulation Test
- Positive Scalp stimulation response
- Fetal Heart Rate increases 15 beats for 15 seconds
- Positive Response implies no acidosis (pH > 7.20)
- Fetal Scalp Blood Sample Analysis
- Normal
- pH: 7.25-7.35 (mean 7.33)
- pCO2: 40-50 mmHg
- pO2: 20-30 mmHg
- Base: <10
- Non-reassuring findings (see interpretation below)
- pH <7.20
- Base Excess < -12 mmol/liter
- Metabolic Acidosis
- pH: <7.25
- pCO2: 45-55 mmHg
- pO2: <20 mmHg
- Base: >10
- Respiratory Acidosis
- pH: <7.25
- pCO2: >50 mmHg
- pO2: Varies
- Base: <10
- Technique
- Amnioscope tube passed via dilated Cervix
- Guarded knife produces blood droplets for sample
- Adverse Effects
- Fetal scalp Hemorrhage
- Bleeding may be difficult to control
- Interpretation
- Scalp pH >= 7.25 and FHT remains non-reassuring
- Continue to observe labor
- Repeat scalp sampling every 2-3 hours
- Scalp pH >= 7.20 and FHT remains non-reassuring
- Repeat Scalp sample in 15-30 minutes
- Scalp pH < 7.20
- Repeat Scalp sample immediately
- If no change in pH then immediate delivery
- Efficacy
- Reduces number of unnecessary Cesarean Sections
- False Positive Rate if scalp pH <7.20: <20%