The Potency of Prophylactic Norepinephrine and Phenylephrine Boluses for Postspinal Anesthesia Hypotension

General Hospital of Ningxia Medical University

Status: Unknown

Conditions: Adverse Effect

Treatments: Drug: Norepinephrine; Drug: Phenylephrine

Study type: Interventional

Funder types: Other

Identifiers

NCT05035472

Yi Chen-2021-3

Details and patient eligibility

About

The purpose of this study is to investigate the potency between prophylactic norepinephrine and phenylephrine boluses for postspinal anesthesia hypotension in patients with severe preeclampsia during caesarean section.

Full description

Preeclampsia, which affects 5% to 7% of patients, is a significant cause of maternal and neonatal morbidity and mortality. Because of constricted myometrial spiral arteries with exaggerated vasomotor responsiveness, though blood pressure in patients with preeclampsia are apparently higher than healthy patients, placental hypoperfusion is more common. Spinal anesthesia is still the preferred mode of anesthesia in patients with preeclampsia for cesarean section. In preeclampsia patients, spinal anesthesia improve intervillous blood flow (provided that hypotension is avoided) which contribute to increase placental perfusion. Even so, 17-26% patients with preeclampsia experienced postspinal anesthesia hypotension due to the extensive sympathetic block that occurred with spinal anesthesia. As a potential substitute drug for phenylephrine and ephedrine, norepinephrine has gained traction for use in patients undergoing cesarean section. However, the ED50 (prevent postspinal hypotension in 50% of patients) and ED90 of prophylactic norepinephrine bolus is still unknown. The purpose of this study is to investigate the potency between prophylactic norepinephrine and phenylephrine boluses for postspinal anesthesia hypotension in patients with severe preeclampsia during caesarean section.

Enrollment: 80 estimated patients

Sex: Female

Ages: 18 to 45 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• 18-45 years
• Primipara or multipara
• Singleton pregnancy ≥32 weeks
• American Society of Anesthesiologists physical status classification II to III
• Scheduled for cesarean section under spinal anesthesia

Exclusion criteria

• Baseline blood pressure ≥180 mmHg
• Body height < 150 cm
• Body weight > 100 kg or body mass index (BMI) ≥ 40 kg/m2
• Eclampsia or chronic hypertension
• Hemoglobin < 7g/dl
• Fetal distress, or known fetal developmental anomaly

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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80 participants in 2 patient groups

Phenylephrine group

Active Comparator group

Description:

Prophylactic phenylephrine bolus simultaneous with spinal anesthesia

Treatment:

Drug: Phenylephrine

Norepinephrine group

Experimental group

Description:

Prophylactic norepinephrine bolus simultaneous with spinal anesthesia

Treatment:

Drug: Norepinephrine