Cardiac Index Changes With Ephedrine, Phenylephrine, Ondansetron and Norepinephrine During Spinal Anesthesia (EPhON)

Cardiac Index Changes With Ephedrine, Phenylephrine, Ondansetron and Norepinephrine During Spinal Anesthesia

Cardiac Index Changes With Ephedrine, Phenylephrine, Ondansetron and Norepinephrine During Spinal Anesthesia for Cesarian Section

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.

will receive ephedrine :a bolus of 9 mg after SA once intervention: will receive complementary doses of ephedrine 6 mgto maintain systolic blood pressure above 80 % of baseline

will receive Phenylephrine : a bolus of 100 mcg once intervention: will receive complementary doses of ephedrine 6 mg to maintain systolic blood pressure above 80 % of baseline

will receive ondansetron: a bolus of 8 mg once intervention: will receive complementary doses of ephedrine 6 mg to maintain systolic blood pressure above 80 % of baseline

will receive noradrenaline (norepinephrine) a bolus of 0,25 mcg/kg once intervention: will receive complementary doses of ephedrine 6 mg to maintain systolic blood pressure above 80 % of baseline

cardiac output: CO (cm3 / min) = ITV * S * HR . ITV (cm) = integral time velocity is measured by pulsed doppler at the level of the ascending aorta, on apical cut.

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

cardiac output: CO (cm3 / min) = ITV * S * HR. ITV (cm) = integral time velocity is measured by pulsed doppler at the level of the ascending aorta, on apical cut.

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

cardiac output: CO (cm3 / min) = ITV * S * HR. ITV (cm) = integral time velocity is measured by pulsed doppler at the level of the ascending aorta, on apical cut.

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

cardiac output: CO (cm3 / min) = ITV * S * HR. ITV (cm) = integral time velocity is measured by pulsed doppler at the level of the ascending aorta, on apical cut.

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

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.

Measurement of systolic, diastolic and mean, non-invasive blood pressure during cesarean delivery with an infusion of either Ephedrine, Phenylephrine, Ondansetron or Norepinephrine

mean heart rate during cesarean delivery with an infusion of either Ephedrine, Phenylephrine, Ondansetron or Norepinephrine

incidence of Vomiting during cesarean section with an infusion of either Ephedrine, Phenylephrine, Ondansetron or Norepinephrine

fetal cord blood analysis will be done immediately after delivery in order to determine the pH value in each group

incidence of nausea during cesarean section with an infusion of either Ephedrine, Phenylephrine, Ondansetron or Norepinephrine

Inclusion Criteria: ASA I / II Caesarean section, non-twinned Exclusion Criteria: heart disease HTA non-gestational diabetes pre-eclampsia sepsis BMI greater than 40 contraindication to spinal anesthesia: patient refusal, medicinal allergy, long QT syndrome.