Fenilefrina y efedrina en cesáreas

Estudio comparativo de infusiones de fenilefrina, efedrina y fenilefrina con efedrina sobre la hemnodinámica materna en cesárea electiva A comparative study of infusions of phenylephrine, ephedrine and phenylephrine plus ephedrine on maternal haemodynamics in elective caesarean section. Das S, Mukhopadhyay S, Mandal M, Mandal S, Basu SR. Indian J Anaesth 2011;55:578-83 Introduction: This randomized double blind study was started with an objective of management of spinal anaesthesia-induced hypotension in elective caesarean section by combining two commonly used vasopressors - ephedrine and phenylephrine in half of their usual doses with an expectation of reducing their foetomaternal side effects. Methods: One hundred and thirty two patients were randomized into three groups to receive either 100 mg/ml phenylephrine (group-P, n=31) or 3 mg/ml ephedrine (group-E, n=33) or 50 mg phenylephrine plus 1.5 mg ephedrine/ml (group-PE, n=29). Immediately after spinal injection the study solution was started prophylactically in every patient at the rate of 40 ml/h. A predefined algorithm was used to adjust the infusion rate according to the systolic blood pressure (SBP). Results: Mean fall of SBP was significantly more in group-E than group-P (P=0.009) and group-PE (P=0.013). This was not significantly different when compared between group-P and group-PE (P=0.9). Episodes of hypotension and tachycardia were more in group-E than the other two groups. Statistically significant tachycardia was seen in Group-E than that in other two groups. Incidence of bradycardia and hypertension did not differ significantly among the groups. Maternal nausea and Apgar score were also comparable in three groups. Conclusion: Current study claims that prophylactic phenylephrine 100 mg/ml is a better choice than ephedrine (3 mg/ml) or 50 mcg phenylephrine plus 1.5 mg ephedrine/ml in prevention of spinal anaesthesia-induced hypotension in elective caesarean section. Combination of two drugs in half the usual dose has no added advantage over phenylephrine, but this is better than ephedrine alone. from: http://www.ijaweb.org/text.asp?2011/55/6/578/90612  Estudio randomizado, doble ciego y comparativo de infusión de fenilefrina y efedrina combinadas para mantener la presión arterial durante raquia para cesárea: el efecto sobre el estado ácido base y control hemodinámico A Randomized Double-Blinded Comparison of Phenylephrine and Ephedrine Infusion Combinations to Maintain Blood Pressure During Spinal Anesthesia for Cesarean Delivery: The Effects on Fetal Acid-Base Status and Hemodynamic Control Warwick D. Ngan Kee, MBChB, MD, FANZCA, Anna Lee, MPH, PhD, Kim S. Khaw, MBBS, FRCA, Floria F. Ng, RN, BASc, Manoj K. Karmakar, MBBS, FRCA, Tony Gin, MBChB, MD, FRCA, FANZCA Anesth Analg 2008;107:1295-1302. BACKGROUND: Phenylephrine and ephedrine are both used to maintain arterial blood pressure during spinal anesthesia for cesarean delivery. Usually, either drug is given alone but several previous studies have described combining the drugs. However, the effect of varying the proportion of vasopressors in such combinations has not been reported. METHODS: One-hundred-twenty-five parturients having spinal anesthesia for elective cesarean delivery were randomized to receive an IV infusion of phenylephrine and ephedrine combined in one of five different concentration ratios. Assuming phenylephrine 100 _g to be approximately equipotent to ephedrine 8 mg, the groups contained the proportional potency equivalent of 100%, 75%, 50%, 25% or 0% of phenylephrine and 0%, 25%, 50%, 75% or 100%, respectively, of ephedrine. The infusions were adjusted to maintain systolic blood pressure (SBP) near baseline until uterine incision. Hemodynamic changes and umbilical cord blood gases were compared. RESULTS: As the proportion of phenylephrine decreased and proportion of ephedrine increased among the groups, the following significant trends were detected: the incidences of hypotension and nausea/vomiting increased, the median magnitude of deviations of SBP above or below baseline and the bias for SBP to be above baseline increased, maternal heart rate was faster, fetal pH and base excess decreased, umbilical arterial oxygen content decreased and umbilical venous Po2 increased. CONCLUSIONS: When varying combinations of phenylephrine and ephedrine were given by infusion to maintain arterial blood pressure during spinal anesthesia for cesarean delivery, as the proportion of phenylephrine decreased and the proportion of ephedrine increased, hemodynamic control was reduced and fetal acid-base status was less favorable. Combinations of phenylephrine and ephedrine appear to have no advantage compared with phenylephrine alone when administered by infusion for the prevention of hypotension associated with spinal anesthesia for cesarean delivery. http://www.anesthesia-analgesia.org/content/107/4/1295.full.pdf

Atentamente Dr. Benito Cortes-Blanco Anestesiología y Medicina del Dolor www.anestesia-dolor.org