Prophylactic phenylephrine for caesarean section under spinal anaesthesia: systematic review and meta-analysis

Heesen, M.; Klöhr, S.; Rossaint, Rolf; Straube, Sebastian

doi:10.1111/anae.12445

Cited by 91 publications

(67 citation statements)

References 44 publications

(51 reference statements)

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“…50 In a review of randomized, controlled trials of spinal anesthesia and caesarean section, the administration of prophylactic intravenous phenylephrine before delivery reduced the risk of hypotension by 64% compared with placebo and after delivery reduced the risks of hypotension, nausea, and vomiting by a similar amount. 51 In recent years, phenylephrine rather than ephedrine has become the vasopressor of choice in obstetrics. 52 …”

Section: Labor and Deliverymentioning

confidence: 99%

Cardiovascular Physiology of Pregnancy

2014

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1003P regnancy is a dynamic process associated with significant physiological changes in the cardiovascular system. These changes are mechanisms that the body has adapted to meet the increased metabolic demands of the mother and fetus and to ensure adequate uteroplacental circulation for fetal growth and development. Insufficient hemodynamic changes can result in maternal and fetal morbidity, as seen in preeclampsia and intrauterine growth retardation. In addition, maternal inability to adapt to these physiological changes can expose underlying, previously silent, cardiac pathology, which is why some call pregnancy nature's stress test. Indeed, cardiovascular disease in pregnancy is the leading cause of maternal mortality in North America. 1 We therefore review here the normal cardiovascular physiology of pregnancy to provide clinicians with a basis for understanding how the presence of cardiovascular disease may compromise the mother and fetus and how their decisions about medical care may need adjustment. Maternal Hemodynamic ChangesPregnancy is associated with vasodilation of the systemic vasculature and the maternal kidneys. The systemic vasodilation of pregnancy occurs as early as at 5 weeks and therefore precedes full placentation and the complete development of the uteroplacental circulation.2 In the first trimester, there is a substantial decrease in peripheral vascular resistance, which decreases to a nadir during the middle of the second trimester with a subsequent plateau or slight increase for the remainder of the pregnancy 3 ( Figure 1). The decrease is ≈35% to 40% of baseline. Systemic vascular resistance increases to near-prepregnancy levels postpartum, 4 and by 2 weeks after delivery, maternal hemodynamics have largely returned to nonpregnant levels.5 Increased vascular distensibility, or compliance, has been observed in normal human pregnancy starting in the first trimester.6 Systemic vascular resistance increases to nearprepregnancy levels postpartum. 4 Vasodilation of the kidneys results in a 50% increase in renal plasma flow and glomerular filtration rates by the end of the first trimester. This results in decreases in serum creatinine, urea, and uric acid values. Cardiac OutputCardiac output increases throughout pregnancy.8 Invasive measuring techniques are rarely used during pregnancy, so echocardiography is most commonly used to assess hemodynamics in pregnancy. Cardiac output measurements are usually made with the mother in the left lateral decubitus position to avoid positional variation. The sharpest rise in cardiac output occurs by the beginning of the first trimester, and there is a continued increase into the second trimester.9 After the second trimester, there is debate as to whether cardiac output increases, decreases, or plateaus. By 24 weeks, the increase in cardiac output can be up to 45% in a normal, singleton pregnancy. 10Echocardiography and cardiac magnetic resonance imaging estimates of cardiac output trend similarly in pregnancy. In a comparative study of 34 normal pregna...

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Section: Labor and Deliverymentioning

confidence: 99%

Cardiovascular Physiology of Pregnancy

2014

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“…[2] A recent systematic review concluded that prophylactic phenyl ephrine infusions reduced maternal hypotension, nausea and vomi ting without altering other relevant maternal or neonatal outcomes. [22] The setting of this work is elective CS in healthy patients, in ideal clinical conditions. In a recent editorial, Butwick et al [16] noted that the potential impact of phenylephrine infusions in a number of higherrisk groups, including women undergoing unplanned CS, has not been well elucidated.…”

Section: Vasopressor Management Strategiesmentioning

confidence: 99%

Recipes for obstetric spinal hypotension: The clinical context counts

2016

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Hypotension following obstetric spinal anaesthesia remains a common and important problem. While recent research advances have brought us closer to the perfect recipe for the obstetric spinal anaesthetic, these advances have not been translated into practical guidelines able to reduce the unacceptable number of fatalities that occur in environments where resources are limited. In South Africa, more than half of anaesthetic deaths are still related to spinal hypotension. A gap exists between the 'perfect recipe' , developed from a clinical context rooted in resourcerich research environments, and its application and performance in realworld resourcepoor environments -conditions experienced by more than 75% of the world's population. This review attempts to define this knowledge gap and proposes a research agenda to address the deficiencies.

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“…The current study provides further confirmation of how effective an α-adrenergic receptor agonist, delivered as a prophylactic infusion in combination with crystalloid coload, can be in preventing maternal spinal hypotension. 10 The findings of a lower incidence of bradycardia and a smaller decrease in cardiac output despite similar blood pressure maintenance with norepinephrine compared to phenylephrine are very encouraging. however, future research needs to address a number of questions before norepinephrine is considered preferable to phenylephrine for maintaining maternal hemodynamics.…”

Section: Editorial Viewsmentioning

confidence: 89%

Norepinephrine for Spinal Hypotension during Cesarean Delivery

Carvalho

Dyer

2015

Anesthesiology

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S pinal anesthesia is the technique of choice for elective cesarean delivery; however, the technique results in hypotension in the vast majority of women if not actively prevented. The consequences of spinal hypotension in this setting are proportional to the severity and include nausea and vomiting, decrease in uteroplacental blood flow, fetal acidosis, and, rarely, cardiovascular collapse. There is now wide consensus that phenylephrine is the drug of choice for elective cesarean delivery to prevent and treat spinal hypotension. The majority of studies demonstrating the efficacy of phenylephrine and the superiority of phenylephrine compared to ephedrine have come from ngan Kee et al. These investigators are credited with leading this evidence-based change in obstetric anesthesia practice. 1 ngan Kee's studies have certainly changed our clinical practice from using ephedrine to administering phenylephrine as our primary vasopressor to prevent and treat spinal hypotension. Given this background, we were very interested to read ngan Kee's latest study comparing phenylephrine with norepinephrine. in this issue of anesthesioloGy, ngan Kee et al. 2 report on a double-blinded, randomized clinical trial comparing norepinephrine and phenylephrine infusion for the maintenance of blood pressure during cesarean delivery under spinal anesthesia. The authors found that a computercontrolled infusion of norepinephrine maintained blood pressure as effectively as phenylephrine, but with less bradycardia and less decrease in cardiac output. no significant differences in neonatal outcomes were found. The authors hypothesize that the β-adrenergic receptor agonist activity in addition to the α-adrenergic receptor effects of norepinephrine may make it a preferable drug for maintaining blood pressure. The findings are very interesting and deserve much attention; however, the study does have a number of important methodological features that need to be considered before the role of norepinephrine in the obstetric anesthesia setting is determined. early research to prevent or minimize spinal hypotension has focused primarily on techniques to increase blood volume and venous return such as fluid loading, positioning to minimize aorto-caval compression, and leg wrapping. however, these techniques have proven largely ineffective. 3 More recent studies suggest that in fluid-replete parturients, spinal hypotension is primarily driven by a decrease in sympathetic tone in the arterial system and not by a reduction in central venous pressure due to increased venous capacitance. studies using minimally invasive cardiac output monitors have demonstrated marked reduction in systemic vascular resistance and a modest increase in cardiac output, heart rate, and stroke volume after induction of spinal anesthesia. 4,5 This physiological observation is consistent with the findings that α-agonist vasopressors are the most reliable method for preventing and treating spinal hypotension during cesarean delivery.The lower incidence of bradycardia and the smal...

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Prophylactic phenylephrine for caesarean section under spinal anaesthesia: systematic review and meta-analysis

Cited by 91 publications

References 44 publications

Cardiovascular Physiology of Pregnancy

Cardiovascular Physiology of Pregnancy

Recipes for obstetric spinal hypotension: The clinical context counts

Norepinephrine for Spinal Hypotension during Cesarean Delivery

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