Cesarean section; cardiac output; hypotension

Phenylephrine is effective for the management of spinal anesthesia-induced hypotension in parturients undergoing cesarean delivery under spinal anesthesia. While ephedrine was previously considered the vasopressor of choice in obstetric patients, phenylephrine is increasingly being used. This is largely due to studies suggesting improved fetal acid-base status with the use of phenylephrine as well as the low incidence of hypotension and its related side effects with prophylactic phenylephrine regimens. This review highlights the effects of phenylephrine compared with ephedrine on maternal hemodynamics (arterial blood pressure, heart rate, and cardiac output), and occurrence of intraoperative nausea and vomiting...

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BACKGROUND: Minimizing hypotension associated with spinal anesthesia for cesarean delivery by administration of IV fluids and vasopressors reduces fetal and maternal morbidity. Most studies have concentrated on noninvasive systolic blood pressure (SBP) measurements to evaluate the effect of such regimens. We used a suprasternal Doppler flow technique to measure maternal cardiac output (CO) variables in parturients receiving a phenylephrine infusion combined with the rapid administration of crystalloid or colloid solution at the time of initiation of anesthesia (coload)...

BACKGROUND AND OBJECTIVES: Blood pressure monitoring offers a limited understanding of the hemodynamic consequences of spinal anesthesia for cesarean delivery. The purpose of this study was to assess, with the aid of a non-invasive cardiac output monitor based on bioreactance, the hemodynamic changes during elective cesarean delivery under spinal anesthesia in which intermittent boluses of phenylephrine were used to prevent and treat hypotension. METHODS: This observational study was conducted with the Research Ethics Board approval, and all participants provided written informed consent...

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BACKGROUND: Hypotension is the most common serious side effect of spinal anesthesia for cesarean delivery. There has been a move recently toward the use of phenylephrine as a vasopressor infusion to improve maternal cardiovascular stability and fetal outcome. Although it seems safe in the elective setting, there have been concerns about its propensity for causing an increase in afterload and a baroreceptor-mediated bradycardia in the mother, with a consequent reduction in maternal cardiac output (CO)...

BACKGROUND: Spinal anesthesia for cesarean delivery may cause severe maternal hypotension and a decrease in cardiac output. Compared to assessment of cardiac output via a pulmonary artery catheter, the FloTrac/Vigileo system may offer a less invasive technique. The aim of this study was to evaluate cardiac output and other hemodynamic measurements made using the FloTrac/Vigileo system in patients undergoing spinal anesthesia for elective cesarean section. METHODS: A prospective study enrolling 10 healthy pregnant women was performed...

BACKGROUND: Hypotension after spinal anesthesia for cesarean delivery remains a major clinical problem. Fluid preloading regimens together with vasopressors have been used to reduce its incidence. Previous studies have used noninvasive arterial blood pressure measurement and vasopressor requirements to evaluate the effect of preload. We used a suprasternal Doppler flow technique to measure maternal cardiac output (CO) and corrected flow time (FTc, a measure of intravascular volume) before and after spinal anesthesia after 3 fluid preload regimens...

BACKGROUND: Hypotension following spinal anesthesia for Cesarean delivery is common. Fluid loading is recommended to prevent hypotension, but preload is often ineffective. In non-pregnant patients, coloading has been shown to better maintain cardiac output after spinal anesthesia. The purpose of this meta-analysis was to determine whether the timing of the fluid infusion, before (preload) or during (coload) induction of spinal anesthesia for Cesarean delivery, influences the incidence of maternal hypotension or neonatal outcome...

BACKGROUND: Hemodynamic responses to vasopressors used during spinal anesthesia for elective Cesarean delivery, have not been well described. This study compared the effects of bolus phenylephrine and ephedrine on maternal cardiac output (CO). The hypothesis was that phenylephrine, but not ephedrine, decreases CO when administered in response to hypotension during spinal anesthesia. METHODS: Forty-three patients were randomized to receive 80 microg of phenylephrine or 10 mg of ephedrine...

BACKGROUND: Spinal anesthesia for cesarean delivery may cause severe maternal hypotension, and a decrease in cardiac output (CO) and blood flow to the placenta. Fluid preloading with crystalloid is ineffective due to rapid redistribution. A "coload" given at the time of cerebrospinal fluid identification may be more effective. Our null hypothesis was that there would be no difference between the effect of a colloid preload (15 mL/kg hydroxyethyl starch (HES) 130/0.4 [Voluven 6%]) and an identical coload on maternal CO and the incidence of hypotension after spinal anesthesia for cesarean delivery...

Oxytocin is a commonly used uterotonic that can cause significant and even fatal hypotension, particularly when given as a bolus. The resulting hypotension can be produced by a decrease in systemic vascular resistance or cardiac output through a decrease in venous return. Parturients with normal volume status, heart valves and pulmonary vasculature most often respond to this hypotension with a compensatory increase in heart rate and stroke volume. Oxytocin-induced hypotension at cesarean delivery may be incorrectly attributed to blood loss...

BACKGROUND: Hemodynamic responses to spinal anesthesia (SA) for cesarean delivery in patients with severe preeclampsia are poorly understood. This study used a beat-by-beat monitor of cardiac output (CO) to characterize the response to SA. The hypothesis was that CO would decrease from baseline values by less than 20%. METHODS: Fifteen patients with severe preeclampsia consented to an observational study. The monitor employed used pulse wave form analysis to estimate nominal stroke volume...

BACKGROUND: The cardiovascular effects of oxytocin in animal models and women undergoing Caesarean section include tachycardia, hypotension and decrease in cardiac output. These can be sufficient to cause significant compromise in high-risk patients. We aimed to find a simple way to decrease these risks whilst retaining the benefits of oxytocin in decreasing bleeding after delivery. Method. We recruited 30 women undergoing elective Caesarean section. They were randomly allocated to receive 5 u of oxytocin either as a bolus injection (bolus group) or an infusion over 5 min (infusion group)...

BACKGROUND: Sequential (Seq) combined spinal epidural (CSE) may provide better cardiovascular stability than standard (Std) CSE for cesarean delivery. We compared the cardiovascular stability of both techniques using suprasternal Doppler. METHODS: Healthy women (n = 40) scheduled for elective cesarean delivery were randomized into two groups; Std or Seq CSE. Serial measures of cardiac output indices, including minute distance, stroke distance, stroke volume, peak velocity, and corrected flow time, were recorded before and after intravascular fluid administration and after CSE...

PURPOSE OF REVIEW: Historically, ephedrine has been recommended as the best vasopressor in obstetrics because animal studies showed it caused less reduction in uterine blood flow compared with alpha-agonists. Recent clinical evidence, however, suggests that this is not as important as initially thought. This review evaluates current data with a focus on spinal anesthesia for cesarean section. RECENT FINDINGS: Ephedrine and phenylephrine have been most investigated...

BACKGROUND AND OBJECTIVE: Epidural and spinal anaesthesia are the preferred mode of anaesthesia for Caesarean section. Volume preloading is recommended to prevent maternal hypotension and a reduction in uteroplacental blood flow, although positive effects of volume preloading on maternal cardiac output and arterial pressure are debatable. Doppler measurements of the umbilical artery beyond deriving pulsatility indices are not routinely performed. METHODS: After Institutional Review Board approval and written informed consent, 14 consecutiVe women with epidural anaesthesia for Caesarean section received either hydroxyethyl starch 500 mL or gelatine 500 mL...

The low-dose technique of combined spinal/epidural analgesia is to be welcomed in obstetrics. Its merits include rapid onset of analgesia, with the flexibility of an epidural technique, and high maternal satisfaction. It is a safe and effective technique. Pulse oximetry should be employed when using intrathecal opioids. Commercially available combined-needle devices may make this technique more attractive to users. The role of spinal anesthesia for emergency cesarean section in severe preeclampsia has been reevaluated recently...

All epidural or spinal techniques using local anaesthetics causes some degree of sympathetic blockade resulting in peripheral vasodilatation and possibly hypotension or reduction in cardiac output. In the practical clinic, administration of fluids intravenously prior spinal and epidural anaesthesia is required to prevent maternal hypotension and fetal hypoxia. We evaluated in this review the efficacy of volume preloading on the incidence of hypotension after spinal or epidural anaesthesia for caesarean delivery...

BACKGROUND: The role of crystalloid preloading to prevent hypotension associated with spinal anesthesia in parturients during cesarean section has been challenged. Direct measurement of blood volume should provide insight regarding the volume-expanding effects. The aim of the current study was to clarify the effects of volume preload with either crystalloid or colloid solution on the changes in blood volume of parturients undergoing spinal anesthesia for cesarean section. METHODS: Thirty-six healthy parturients scheduled for elective cesarean section during spinal anesthesia were allocated randomly to one of three groups receiving 1...