Background and rationale: The best agent to prevent spinal-induced hypotension is still uncertain but norepinephrine showed fewer effects on heart rate and cardiac output. In septic patients norepinephrine has been shown to produce an "endogenous fluid challenge". Objective: We aim to assess if patients with impaired diastolic function (46% of pregnant women at term) are less able to maintain indexed cardiac output in response to norepinephrine infusion during spinal-induced vasoplegia. We also aim to assess if fetal wellbeing is related to maternal cardiac output during spinal anesthesia for cesarean delivery. Methods: We will assess by echocardiogram the diastolic function before surgery and will then start continuous non-invasive hemodynamic monitoring with a ClearSight® monitor (ClearSight®, Edwards Lifescience, Irvine, CA) and perform a fluid challenge to relate diastolic disfunction with fluid responsiveness. Hemodynamic monitoring will continue throughout the surgery. Norepinephrine infusion will start concomitantly to beginning of spinal anesthesia and will stop 5 minutes after uterotonic medication. Outcome: We aim to assess if patients with diastolic disfunction are less able to maintain cardiac output in response to norepinephrine infusion during spinal anesthesia induced vasoplegia. We also aim to assess if fetal wellbeing is related to maternal cardiac output during spinal anesthesia for cesarean delivery.)
Study Type
OBSERVATIONAL
Enrollment
40
Norepinephrine is administered as a continuous infusion at 0.05 mcg/kg/min and is kept to maintain systolic blood pressure within 90-120% of baseline during spinal anaesthesia. The infusion is started at the same time cerebrospinal fluid is obtained, immediately before injection of spinal medications, through a small-bore tubing connected directly to the peripheral intravenous catheter. It is stopped 5 minutes
All patients are connected to a ClearSight® monitor (ClearSight®, Edwards Lifescience, Irvine, CA) by an inflatable finger cuff placed on the midphalanx of hand middle or ring finger with no radial artery catheter and its heart reference system (HRS) is zeroed at the level of the patient's midaxillary line. The ClearSight® monitoring is started in the pre-anaesthesia room and calibrated for 5 minutes before recording. The monitoring continues throughout the procedure until patient transfer in the recovery room. All data are anonymously collected on a USB pen for statistical analysis.
IRCCS Fondazione Policlinico Universitario Agostino Gemelli
Rome, Italy
Indexed Cardiac Output
We aim to study if the diastolic performance of the heart measured by transthoracic echocardiography in healthy pregnant women at term undergoing spinal anesthesia for caesarean delivery influences the effects of norepinephrine on indexed cardiac output (CI) measured by non-invasive continuous hemodynamic monitoring.
Time frame: Baseline/after spinal anesthesia/after delivery
Indexed Stroke Volume
We will correlate diastolic performance measured by transthoracic echocardiography with the response to norepinephrine of indexed stroke volume (SVI) in ml, blood pressure (BP) in mmHg and heart rate (HR) in bpm measured by non-invasive continuous hemodynamic monitoring.
Time frame: Baseline/after spinal anesthesia/after delivery
Systolic Blood Pressure
We will correlate diastolic performance measured by transthoracic echocardiography with the response to norepinephrine of blood pressure (BP) in mmHg measured by non-invasive continuous hemodynamic monitoring.
Time frame: Baseline/after spinal anesthesia/after delivery
Heart Rate
We will correlate diastolic performance measured by transthoracic echocardiography with the response to norepinephrine of heart rate (HR) in bpm measured by non-invasive continuous hemodynamic monitoring.
Time frame: Baseline/after spinal anesthesia/after delivery
Apgar Scores
We ought to correlate the reduction of neonatal Apgar Scores with decreases of indexed cardiac output measured by non-invasive continuous hemodynamic monitoring.
Time frame: Decreases of Indexed Cardiac Output after spinal anesthesia
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