Spinal and epidural anesthesia, fetal and uterine response to acute hypo- and hypertension

Abstract

1.1. Spinal or epidural anesthesia does not abolish uterine contractility as long as the blood pressure is maintained within normal limits. Factors associated with sensation of pain, bearing down, muscle rigidity, etc., which may enhance or inhibit uterine contractility, however, are abolished by spinal or epidural anesthesia. Although labor after spinal or epidural anesthesia may be altered, the intrinsic uterine work is preserved. In the clinical estimation of the duration of labor in patients with spinal or epidural anesthesia these factors should be considered.2.2. Acute postepidural hypotension resulted in a decrease of uterine contractility, fetal tachycardia, and oscillation of the fetal heart rate. Fetal bradycardia was encountered either with a severe maternal hypotension or more frequently with enhancement of uterine contractility following a posthypotensive period.3.3. Correction of an acute hypotension with one intravenous injection of 3 mg. of methoxamine hydrochloride resulted in 8 cases in tetanic uterine contraction and severe fetal distress.4.4. It is suggested in the management of postspinal hypotension by pressor amines that the intravenous drip should be used and the dose and effect individually followed by clinical monitoring of the fetal heart rate, uterine contractility, and the maternal hemodynamic status.