The purpose of the study is to evaluate the cardiac output changes after an intravenous bolus of ephedrine, phenylephrine, ondansetron or norepinephrine during a spinal anesthetic for a cesarean delivery. For elective cesarean delivery, all participants will receive spinal anesthesia with a local anesthetic and sufentanil. This study includes 120 pregnant women. Patients will be randomly assigned according to a computer generated system to be in one of four groups.
This study will be a prospective, randomized, double-blind controlled trial. After written and informed consent are obtained, the study participants are randomly assigned using a computer generated table to 1 of 4 treatment groups prior to cesarean delivery. Group A: 9 mg of ephedrine Group B: 100 mcg of phenylephrine Group C: 8 mg of ondansetron Group D: 0,25 mcg/kg of norepinephrine Baseline arterial blood pressure and heart rate will be measured in the left lateral tilt position, before anesthesia and then every minute.The cardiac output is calculated on the apical cut 5 cavities, before anesthesia and then every 5 miutes. No fluid preloading will be administered till delivery. The primary endpoint is cardiac output changes in each groups. The secondary endpoint is the number of provider interventions needed to maintain the SBP within 80-120% of baseline for each groups. Bradycardia (HR less than 50 BPM) will be treated with 1 mg of Atropine. Hypotension ( decrease of more than 20% of the baseline value or a PAS \<90 mm Hg) will be treated with 6 mg of ephedrine, without any fluid loading. The spinal anesthesia will be carried out in a seated position, level L3-L4 or L4-L5 with a slow injection over 30 seconds of a mixture of 10 mg of 0.5% Bupivacaine with 5 mcg of Sufentanil. The hot / cold test to determine the block level is required. A spinal anesthesia is validated if the cold test reaches the T4 level. The 10 ml syringe will be administered immediately after spinal anesthesia. The patient will be placed in the left lateral tilt position of 15¤, then put back into strict DD immediately after the delivery. Cardiovascular parameters (PAS, PAM, PAD, HR) will be recorded every minute until delivery. Echocardiographic measurement of cardiac output will be recorded every five minutes until delivery. Measured variables will include systolic, diastolic and mean non-invasive blood pressure, the number and type of interventions for control of blood pressure, heart rate, cardiac output, incidence of nausea and vomiting (NV), incidence of arrhythmia and fetal cord blood analysis (pH) at delivery.
Study Type
INTERVENTIONAL
measure cardiac output after giving a bolus of ephedrine intervention: will receive complementary doses of ephedrine to maintain systolic blood pressure above 80 % of baseline
measure cardiac output after giving a bolus of phenylephrine intervention: will receive complementary doses of ephedrine to maintain systolic blood pressure above 80 % of baseline
measure cardiac output after giving a bolus of ondansetron intervention: will receive complementary doses of ephedrine to maintain systolic blood pressure above 80 % of baseline
Tunis maternity and neonatology center, minisetry of public health
Tunis, Tunisia
cardiac output changes for 120 patients
In left lateral tilt position, cardiac output is calculated on the echocardiographic apical cut 5 cavities, every 5 minutes till delivery, with an infusion of either Ephedrine, Phenylephrine, Ondansetron or Norepinephrine. The cardiac output is calculated on the apical cut 5 cavities: Dc (cm3 / min) = ITV \* S \* HR Dc = cardiac output ITV (cm) = integral time velocity is measured by pulsed doppler at the level of the ascending aorta, on apical cut. Only the closing click (B2) is visible. If B2 is not visible, the sample is placed too much in the hunting chamber, which underestimates the ITV. If B1 and B2 are visible, the sample is too close to the aortic ring, which overestimates the ITV measurement. S = surface area of the aortic ring = (aorta diameter) ₂ \* π / 4 The diameter of the aorta is the average of three measurements at the beginning of systole, on the major axis.
Time frame: at time of delivery (right after spinal anesthesia until delivery)
Maternal Blood Pressure
Measurement of systolic, diastolic and mean, non-invasive blood pressure during cesarean delivery with an infusion of either Ephedrine, Phenylephrine, Ondansetron or Norepinephrine
Time frame: at time of delivery (right after spinal anesthesia until delivery)
heart rate
mean heart rate during cesarean delivery with an infusion of either Ephedrine, Phenylephrine, Ondansetron or Norepinephrine
Time frame: at time of delivery (right after spinal anesthesia until delivery)
Vomiting
incidence of Vomiting during cesarean section with an infusion of either Ephedrine, Phenylephrine, Ondansetron or Norepinephrine
Time frame: at time of delivery (right after spinal anesthesia until delivery)
mean pH of the fetal cord blood
fetal cord blood analysis will be done immediately after delivery in order to determine the pH value in each group
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Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
120
measure cardiac output after giving a bolus of nor-epinephrine intervention: will receive complementary doses of ephedrine to maintain systolic blood pressure above 80 % of baseline
Time frame: at time of delivery (right after spinal anesthesia until delivery)
Nausea
incidence of nausea during cesarean section with an infusion of either Ephedrine, Phenylephrine, Ondansetron or Norepinephrine
Time frame: at time of delivery (right after spinal anesthesia until delivery)