What is the immediate management for a laboring patient experiencing tachysystole?

Immediate Management of Tachysystole in Labor

Stop any uterotonic agents immediately (oxytocin, prostaglandins), reposition the patient to left lateral decubitus, administer maternal oxygen, and increase IV fluid rate while continuously monitoring fetal heart rate patterns. 1

Definition and Recognition

• Tachysystole is defined as more than 5 contractions in a 10-minute period, averaged over a 30-minute window 1
• This definition applies to both spontaneous and stimulated labor 1
• The term "hyperstimulation" is outdated and should be abandoned 1
• Tachysystole must be qualified by the presence or absence of fetal heart rate decelerations 1

Immediate Resuscitative Measures

First-line interventions (perform simultaneously):

• Discontinue oxytocin or any labor-stimulating agents immediately 1
• Position patient in left lateral decubitus to optimize uterine blood flow and relieve inferior vena cava compression 1, 2
• Administer supplemental oxygen via face mask 3
• Increase IV fluid rate to improve maternal intravascular volume 3
• Perform continuous electronic fetal heart rate monitoring to assess for decelerations 1

Assessment of Fetal Status

Evaluate the fetal heart tracing using the DR C BRAVADO mnemonic: 1

• Determine Risk (DR): Assess clinical risk status (low, medium, high) 1
• Contractions (C): Confirm tachysystole pattern and assess intensity 1
• Baseline Rate (BRA): Check for bradycardia (<110 bpm), normal (110-160 bpm), or tachycardia (>160 bpm) 1
• Variability (V): Assess for absent, minimal, moderate, or marked variability 1
• Accelerations (A): Look for spontaneous or stimulated accelerations (≥15 bpm for ≥15 seconds) 1
• Decelerations (D): Identify absent, early, variable, late, or prolonged decelerations 1

Tocolytic Therapy

If conservative measures fail and fetal heart rate abnormalities persist:

• Administer subcutaneous terbutaline 0.25 mg as acute tocolysis 4
• Terbutaline (a selective β2-adrenergic agonist) probably reduces abnormal fetal heart tracings (RR 0.28,95% CI 0.08-0.95) 4
• Alternative: IV hexoprenaline or other β2-agonists if available 4
• Tocolytics should be used when conservative measures fail and there is evidence of fetal compromise 4, 5

When to Escalate to Emergency Delivery

Prepare for emergency cesarean section if:

• Persistent Category III fetal heart rate tracing despite resuscitative measures 1
• Prolonged fetal bradycardia (>10 minutes) 1
• Recurrent late or severe variable decelerations with minimal or absent variability 1
• Sinusoidal pattern suggesting severe fetal compromise 1
• Maternal hemodynamic instability requires immediate electrical cardioversion if arrhythmia is present 1, 3

Monitoring Intensity

Continuous monitoring requirements:

• Maintain continuous electronic fetal monitoring throughout the episode 1
• Assess fetal heart rate every 5 minutes during active management 1
• Consider intrauterine pressure catheter (IUPC) if external monitoring inadequate to assess contraction strength 1, 6
• Continue monitoring for at least 30 minutes after tachysystole resolves to ensure stability 1

Common Pitfalls to Avoid

• Do not delay stopping oxytocin while waiting to assess fetal response—stop immediately 1, 4
• Do not assume external tocodynamometry accurately reflects contraction strength; consider IUPC if needed 1, 6
• Do not ignore tachysystole without decelerations—it still warrants intervention and close monitoring 1, 7
• Tachysystole occurs in >10% of spontaneous labors and is associated with increased cesarean delivery rates and NICU admissions even without obvious fetal heart rate changes 7
• Epidural analgesia is associated with higher rates of tachysystole (aOR 1.89), so maintain heightened vigilance 7

Special Considerations

• Tachysystole with accompanying decelerations significantly increases risk of fetal acidosis if uncorrected 1
• Non-white patients (Hispanic, African American, Asian) have 1.5-1.7 times higher incidence of tachysystole 7
• Nulliparous women and those with higher fetal weight are at increased risk 7
• If tachysystole occurs with prostaglandin induction agents (misoprostol), remove vaginal insert if possible 8