Adverse Effect
Conditions
Brief summary
The objective of this study is to investigate the ED90 of norepinephrine and phenylephrine infusions for preventing postspinal anesthesia hypotension under intensive treatment during cesarean section
Detailed description
Post-spinal anesthesia hypotension is a frequent complication during spinal anesthesia for cesarean section. The incidence of post-spinal anesthesia hypotension is as high as 62.1-89.7% if prophylactic measures are not taken. The 2016 ASA guidelines for obstetric anesthesia suggest avoiding hypotension following spinal anesthesia in women and emphasize the use of vasopressors, specifically alpha-receptor agonists, as the preferred strategy to prevent and manage post-spinal anesthesia hypotension. The 2018 International Consensus in the United Kingdom and Northern Ireland recommends maintaining maternal systolic blood pressure above 90% of the baseline value following lumbar anesthesia, while avoiding dropping below 80% of the baseline value. Currently, the threshold for maintaining blood pressure above 80% of the baseline value is widely adopted as a standard; however, limited evidence supports the advantage of sustaining maternal blood pressure above 90% of the baseline value. The objective of this study is to investigate the ED90 of norepinephrine and phenylephrine infusions for preventing postspinal anesthesia hypotension under intensive treatment during cesarean section
Interventions
DRUGNorepinephrine
An initial infusion dose of prophylactic norepinephrine (0.05 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.01 ug/kg/min of prophylactic norepinephrine according to the responses of previous patients according to the up-down sequential allocation.
DRUGPhenylephrine
An initial infusion dose of prophylactic phenylephrine (0.5 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.1 ug/kg/min of prophylactic phenylephrine 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 ≥37 weeks * American Society of Anesthesiologists physical status classification I to II * Scheduled for cesarean section under spinal anesthesia
Exclusion criteria
* Body height \< 150 cm * Body weight \> 100 kg or body mass index (BMI) ≥ 40 kg/m2 * Eclampsia or chronic hypertension or baseline blood pressure ≥180 mmHg * Hemoglobin \< 7g/dl * Fetal distress, or known fetal developmental anomaly
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| ED50 and ED90 | 1-15 minutes after spinal anesthesia | The doses of prophylactic norepinephrine and phenylephrine that would be effective in preventing postspinal anesthesia hypotension in 50% (effective dose, ED 50) and 90% (ED90) of patients |
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 |
Other
| Measure | Time frame | Description |
|---|---|---|
| The incidence of nausea and vomiting. | 1-15 minutes after spinal anesthesia | Presence of nausea and vomiting in patients after spinal anesthesia |
| The incidence of hypertension. | 1-15 minutes after spinal anesthesia | Systolic blood pressure (SBP) \>120% of the baseline. |
| pH | Immediately after delivery | From umbilical arterial blood gases. |
| The incidence of severe post-spinal anesthesia hypotension. | 1-15 minutes after spinal anesthesia | Systolic blood pressure (SBP) \< 60% of the baseline. |
| Partial pressure of oxygen (PO2) | Immediately after delivery | From umbilical arterial blood gases. |
| APGAR score | 1 min after delivery | A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration; 0(Worst)-10(Best) |
| Base excess | Immediately after delivery | From umbilical arterial blood gases. |
| The incidence of bradycardia. | 1-15 minutes after spinal anesthesia | Heart rate \< 60 beats/min. |
Countries
China
Outcome results
None listed