90% Effective Dose of Phenylephrine Infusions Under Intensive and Standard Treatment
Study Details
Study Description
Brief Summary
The objective of this study is to investigate the 90% effective dose of phenylephrine infusions for preventing postspinal anesthesia hypotension under intensive and standard treatment during cesarean section
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
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N/A |
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 90% effective dose of phenylephrine infusions for preventing postspinal anesthesia hypotension under intensive and standard treatment during cesarean section.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Other: Standard group The maternal systolic blood pressure was consistently maintained above 80% of the preoperative baseline value from the initiation of spinal anesthesia until fetal delivery. |
Drug: Alpha-Agonist
An initial infusion dose of prophylactic phenylephrine (0.625 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.125 ug/kg/min of prophylactic phenylephrine according to the responses of previous patients according to the up-down sequential allocation.
Other Names:
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| Other: Intensive group The maternal systolic blood pressure was consistently maintained above 90% of the preoperative baseline value from the initiation of spinal anesthesia until fetal delivery. |
Drug: α-adrenergic receptor agonist
An initial infusion dose of prophylactic phenylephrine (0.625 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.125 ug/kg/min of prophylactic phenylephrine according to the responses of previous patients according to the up-down sequential allocation.
Other Names:
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Outcome Measures
Primary Outcome Measures
- ED50 and ED90 [1-15 minutes after spinal anesthesia]
The dose of prophylactic phenylephrine that would be effective in preventing postspinal anesthesia hypotension in 50% (effective dose, ED 50) and 90% (ED90) of patients
Secondary Outcome Measures
- 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
- 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.
- Base excess [Immediately after delivery]
From umbilical arterial blood gases.
- 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)
- APGAR score [5 min after delivery]
A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration; 0(Worst)-10(Best)
Eligibility Criteria
Criteria
Inclusion Criteria:
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18-45 years
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Primipara or multipara
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Singleton pregnancy ≥37 weeks
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American Society of Anesthesiologists physical status classification I to II
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Scheduled for cesarean section under spinal anesthesia
Exclusion Criteria:
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Body height < 150 cm
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Body weight > 100 kg or body mass index (BMI) ≥ 40 kg/m2
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Eclampsia or chronic hypertension or baseline blood pressure ≥180 mmHg
-
Hemoglobin < 7g/dl
Contacts and Locations
Locations
No locations specified.Sponsors and Collaborators
- General Hospital of Ningxia Medical University
Investigators
- Study Chair: Yi Chen, M.D., General Hospital of Ningxia Medical University
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- Yi Chen-2024-4