To the Editor:
The study by Rolbin et al.  on the association of anesthetic technique with preterm neonatal outcome at cesarean section does not surprise us, in that the use of general anesthesia resulted in a greater percentage of low Apgar scores. We were astonished, however, to read that factors such as "placental or cord problems and fetal distress were not associated with an increased risk of low Apgar scores." Information presented in Table 2 states that, of a total of 509 patients in the study, 81 had placental or cord problems, and 121 exhibited fetal distress. We are also told that the "proportion of infants with placental or cord problems, or fetal distress, was, in fact, similar in the general anesthesia and epidural groups." We would like to raise the possibility that since the terms "cord problem, placental problem, and fetal distress" are imprecise, more exacting definitions could have altered the results. If the term "fetal distress," for example, were limited to those fetal heart rate patterns of sufficient severity so as to place the fetus in immediate danger of asphyxial damage , such as profound decelerations with absent variability, or prolonged bradycardia , then one might have had a much smaller, but more significant, sample size of neonatal factors associated with low Apgar score. If the fetus is in immediate jeopardy, however, cesarean section is usually not delayed to establish an adequate sensory level with spinal or epidural block . In the present study, where the anesthetic technique was not randomized, the tendency for the anesthesiologist to exhibit a selection bias toward general anesthesia in such a situation of fetal jeopardy could be strong indeed.
We asked Dr. Cohen for a response but failed to obtain one.
Harold J. Heyman, MD
Ninos J. Joseph, BS
Department of Anesthesiology, Illinois Masonic Medical Center, Chicago, IL 60657
1. Rolbin SH, Cohen MM, Levinton CM, et al. The premature infant: anesthesia for cesarean delivery. Anesth Analg 1994;78:912-7.
2. Parer JT. Diagnosis and management of fetal asphyxia. In: Shnider SM, Levinson G, eds. Anesthesia for obstetrics. Baltimore: Williams & Wilkins, 1993;657-70.
3. Shnider SM, Levinson G. Anesthesia for cesarean section. In: Shnider SM, Levinson G, eds. Anesthesia for obstetrics. Baltimore: Williams & Wilkins, 1993;211-45.