Prophylactic Phenylephrine Infusion for Preventing Hypotension During Spinal Anesthesia for Cesarean Delivery

In a randomized, double-blinded, controlled trial, we investigated the prophylactic infusion of IV phenylephrine for the prevention of hypotension during spinal anesthesia for cesarean delivery. Immediately after intrathecal injection, phenylephrine was infused at 100 &mgr;g/min (n = 26) for 3 min. From that point until delivery, phenylephrine was infused at 100 &mgr;g/min whenever systolic arterial blood pressure (SAP), measured each minute, was less than baseline. A control group (n = 24) received IV bolus phenylephrine 100 &mgr;g after each measurement of SAP <80% of baseline. Phenylephrine infusion decreased the incidence (6 [23%] of 26 versus 21 [88%] of 24; P < 0.0001), frequency, and magnitude (median minimum SAP, 106 mm Hg; interquartile range, 95–111 mm Hg; versus median, 80 mm Hg; range, 73–93 mm Hg; P < 0.0001) of hypotension compared with control. Heart rate was significantly slower over time in the infusion group compared with the control group (P < 0.0001). Despite a large total dose of phenylephrine administered to the infusion group compared with the control group (median, 1260 &mgr;g; interquartile range, 1010–1640 &mgr;g; versus median, 450 &mgr;g; interquartile range, 300–750 &mgr;g; P < 0.0001), umbilical cord blood gases and Apgar scores were similar. One patient in each group had umbilical arterial pH <7.2. Prophylactic phenylephrine infusion is a simple, safe, and effective method of maintaining arterial blood pressure during spinal anesthesia for cesarean delivery.

[1]  David W. Cooper,et al.  Fetal and Maternal Effects of Phenylephrine and Ephedrine during Spinal Anesthesia for Cesarean Delivery , 2002, Anesthesiology.

[2]  S. Datta,et al.  Intravenous fluid preload in the prevention of spinal block-induced hypotension in parturients. , 1994, Anesthesiology.

[3]  D. H. Ralston,et al.  Effects of Equipotent Ephedrine, Metaraminol, Mephentermine, and Methoxamine on Uterine Blood Flow in the Pregnant Ewe , 1974, Anesthesiology.

[4]  T. Mashimo,et al.  Effects of crystalloid and colloid preload on blood volume in the parturient undergoing spinal anesthesia for elective Cesarean section. , 1999, Anesthesiology.

[5]  M. Vercauteren,et al.  Anaphylactoid reaction to hydroxyethylstarch during cesarean delivery in a patient with HELLP syndrome. , 2003, Anesthesia and analgesia.

[6]  I. Russell,et al.  Volume preload: lack of effect in the prevention of spinal-induced hypotension at caesarean section. , 1998, International journal of obstetric anesthesia.

[7]  D. Benhamou,et al.  Phenylephrine Added to Prophylactic Ephedrine Infusion during Spinal Anesthesia for Elective Cesarean Section , 2001, Anesthesiology.

[8]  G. Marx,et al.  Intravenous fluid preload in the prevention of spinal block-induced hypotension in parturients. , 1994, Anesthesiology.

[9]  S. Wollman,et al.  Acute hydration for prevention of hypotension of spinal anesthesia in parturients. , 1968, Anesthesiology.

[10]  W. N. Ngan Kee,et al.  A Quantitative, Systematic Review of Randomized Controlled Trials of Ephedrine Versus Phenylephrine for the Management of Hypotension During Spinal Anesthesia for Cesarean Delivery , 2002, Anesthesia and analgesia.

[11]  J. Reves,et al.  Time Course and Hemodynamic Effects of Alpha‐1‐Adrenergic Bolus Administration in Anesthetized Patients with Myocardial Disease , 1989, Anesthesia and analgesia.

[12]  G. Schüpfer,et al.  Higher Rate of Fetal Acidemia After Regional Anesthesia for Elective Cesarean Delivery , 1997, Obstetrics and gynecology.

[13]  T. Gin,et al.  A Dose-Response Study of Prophylactic Intravenous Ephedrine for the Prevention of Hypotension During Spinal Anesthesia for Cesarean Delivery , 2000, Anesthesia and analgesia.

[14]  W. N. Ngan Kee,et al.  Metaraminol Infusion for Maintenance of Arterial Blood Pressure During Spinal Anesthesia for Cesarean Delivery: The Effect of a Crystalloid Bolus , 2001, Anesthesia and analgesia.

[15]  W. N. Ngan Kee,et al.  Randomized controlled study of colloid preload before spinal anaesthesia for caesarean section. , 2001, British journal of anaesthesia.

[16]  J. Thorp,et al.  Umbilical cord blood gas analysis. , 1999, Obstetrics and gynecology clinics of North America.

[17]  S. Halpern,et al.  The Effects of an Increase of Central Blood Volume Before Spinal Anesthesia for Cesarean Delivery: A Qualitative Systematic Review , 2001, Anesthesia and analgesia.

[18]  F. M. James,et al.  An Evaluation of Vasopressor Therapy for Maternal Hypotension during Spinal Anesthesia , 1970, Anesthesiology.

[19]  C. Rout,et al.  A Reevaluation of the Role of Crystalloid Preload in the Prevention of Hypotension Associated with Spinal Anesthesia for Elective Cesarean Section , 1993, Anesthesiology.

[20]  R. Jackson,et al.  Volume preloading is not essential to prevent spinal-induced hypotension at caesarean section. , 1995, British journal of anaesthesia.

[21]  W D Ngan Kee,et al.  Comparison of Metaraminol and Ephedrine Infusions for Maintaining Arterial Pressure during Spinal Anesthesia for Elective Cesarean Section , 2001, Anesthesiology.

[22]  G. Marx.  Fetal acidemia associated with regional anesthesia for elective cesarean delivery. , 1995, Obstetrics and gynecology.

[23]  S. Alahuhta,et al.  Ephedrine and phenylephrine for avoiding maternal hypotension due to spinal anaesthesia for caesarean section. Effects on uteroplacental and fetal haemodynamics. , 1992, International journal of obstetric anesthesia.

[24]  P A Hall,et al.  Spinal anaesthesia for caesarean section: comparison of infusions of phenylephrine and ephedrine. , 1994, British journal of anaesthesia.

[25]  S. Akoojee,et al.  Rapid administration of crystalloid preload does not decrease the incidence of hypotension after spinal anaesthesia for elective caesarean section. , 1992, British journal of anaesthesia.