The objective of this study is to investigate the 90% effective dose of norepinephrine infusions for preventing postspinal anesthesia hypotension under intensive and standard treatment in preeclamptic patients during cesarean section
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 norepinephrine infusions for preventing postspinal anesthesia hypotension under intensive and standard treatment in preeclamptic patients during cesarean section.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
80
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.
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.
ED50 and ED90
The dose of prophylactic norepinephrine that would be effective in preventing postspinal anesthesia hypotension in 50% (effective dose, ED 50) and 90% (ED90) of patients
Time frame: 1-15 minutes after spinal anesthesia
The incidence of post-spinal anesthesia hypotension
Systolic blood pressure (SBP) \< 80% of the baseline
Time frame: 1-15 minutes after spinal anesthesia
The incidence of severe post-spinal anesthesia hypotension.
Systolic blood pressure (SBP) \< 60% of the baseline.
Time frame: 1-15 minutes after spinal anesthesia
The incidence of bradycardia.
Heart rate \< 60 beats/min.
Time frame: 1-15 minutes after spinal anesthesia
The incidence of nausea and vomiting.
Presence of nausea and vomiting in patients after spinal anesthesia
Time frame: 1-15 minutes after spinal anesthesia
The incidence of hypertension.
Systolic blood pressure (SBP) \>120% of the baseline.
Time frame: 1-15 minutes after spinal anesthesia
pH
From umbilical arterial blood gases.
Time frame: Immediately after delivery
Base excess
From umbilical arterial blood gases.
Time frame: Immediately after delivery
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Partial pressure of oxygen (PO2)
From umbilical arterial blood gases.
Time frame: Immediately after delivery
APGAR score
A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration; 0(Worst)-10(Best)
Time frame: 1 min after delivery
APGAR score
A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration; 0(Worst)-10(Best)
Time frame: 5 min after delivery