title: Effects of prophylactic continuous infusion of phenylephrine on reducing the mass of local anesthetic in patients undergoing spinal anesthesia for cesarean section.
abstract: OBJECTIVE
  Reducing the mass of local anesthetic minimizes the effects of hypotension after spinal anesthesia for cesarean section and the incidence of maternal adverse events preserving fetal well-being, but it may result in insufficient anesthesia. Hypotension associated with greater masses of subarachnoid anesthesia can be controlled by prophylactic continuous infusion of phenylephrine. The effects of prophylactic continuous infusion of phenylephrine on pressure control on maternal and fetus results in cesarean sections with different doses of hyperbaric bupivacaine in spinal anesthesia.
  
  
  METHODS
  A non-randomized prospective study of 60 gravidas at term scheduled for elective cesarean sections was undertaken. Patients were allocated into two groups depending on hyperbaric bupivacaine dose administered for spinal anesthesia, 12 or 8 mg, along with 5 μg of sufentanil and 100 μg of morphine. Patients were hydrated with 10 mL.kg(-1) of Ringer's lactate before the anesthesia. Shortly after, continuous infusion of 100 μg.min(-1) of phenylephrine was initiated to maintain blood pressure at baseline levels. The following parameters were evaluated: level of anesthetic blockade, consumption of vasopressors, incidence of maternal events, and conditions of the newborn.
  
  
  RESULTS
  Maternal data was similar in both groups regarding the level of anesthetic blockade, phenylephrine consumption along time, incidence of hypotension, hypertension, bradycardia, nausea, vomiting, dyspnea, pain, and tremors. Conceptual data showed similarities between both groups regarding blood gases and umbilical vein lactate levels. The pH of all newborns was > 7.2.
  
  
  CONCLUSIONS
  On maintaining the blood pressure with prophylactic continuous infusion of phenylephrine the incidence of maternal adverse events and conditions of birth do not differ whether spinal anesthesia is performed with 12 mg or 8 mg of hyperbaric bupivacaine.
authors: Serviço de Anestesiologia do Hospital Mater Dei, Brazil. vinicius.ps@terra.com.br
authors: Vinícius Pereira
authors: VP
authors: de Souza
authors: José Luiz Gomes
authors: JL
authors: do Amaral
authors: Maria Ângela
authors: MÂ
authors: Tardelli
authors: Américo Massafuni
authors: AM
authors: Yamashita
mesh_terms: D000293:Adolescent; D058646:Adrenergic alpha-1 Receptor Agonists / Q000009:adverse effects*; D000328:Adult; D000773:Anesthesia, Obstetrical; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage*; D002585:Cesarean Section; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007262:Infusions, Intravenous; D010656:Phenylephrine / Q000008:administration & dosage*; D011247:Pregnancy; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D058646:Adrenergic alpha-1 Receptor Agonists; D000779:Anesthetics, Local; D010656:Phenylephrine; D002045:Bupivacaine