Adverse Effect
Conditions
Keywords
Norepinephrine, Phenylephrine, Postspinal anesthesia hypotension, Preeclampsia, Cesarean section
Brief summary
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.
Detailed 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.
Interventions
DRUGPhenylephrine
An initial prophylactic bolus dose of phenylephrine (37.5μg) simultaneous with spinal anesthesia. If the patient did not respond adequately to the current dose (SBP decreased to \< 80% of baseline), the dose was considered to have failed and the subsequent dose for the following patient was increased to the next higher dose level. The dose administered to subsequent patients varied by increments or decrements of 12.5 μg according to the responses of previous patients according to the up-down sequential allocation.
DRUGNorepinephrine
An initial prophylactic bolus dose of norepinephrine (3μg) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 1 μg according to the responses of previous patients according to the up-down sequential allocation.
Sponsors
General Hospital of Ningxia Medical University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Caregiver)
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 45 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| The dose that would be effective in preventing postspinal anesthesia hypotension in 50% (effective dose, ED 50) and 90% (ED90) of patients | 1-15 minutes after spinal anesthesia | Systolic blood pressure (SBP) \< 80% of the baseline |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| The incidence of post-spinal anesthesia hypotension | 1-15 minutes after spinal anesthesia | Systolic blood pressure (SBP) \< 80% of the baseline |
| The incidence of severe post-spinal anesthesia hypotension. | 1-15 minutes after spinal anesthesia | Systolic blood pressure (SBP) \< 60% of the baseline |
| The incidence of bradycardia. | 1-15 minutes after spinal anesthesia | Heart rate \< 60 beats/min. |
| The incidence of nausea and vomiting. | 1-15 minutes after spinal anesthesia | Presence of nausea and vomiting in patients after spinal anesthesia |
| APGAR score | 1 min after delivery | A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration |
| pH | Immediately after delivery | From umbilical arterial blood gases. |
| Partial pressure of oxygen (PO2) | Immediately after delivery | From umbilical arterial blood gases. |
| Base excess (BE) | Immediately after delivery | From umbilical arterial blood gases. |
| The incidence of hypertension. | 1-15 minutes after spinal anesthesia | Systolic blood pressure (SBP) \>120% of the baseline. |
Contacts
Primary ContactXinli Ni, Dr.
Backup ContactYi Chen, M.D.
Outcome results
None listed