Factors affecting fetal bradycardia following combined spinal epidural for labor analgesia: a matched case-control study.
OBJECTIVE
The combined spinal epidural (CSE) technique for labor analgesia has become increasingly popular owing to its rapid onset of analgesia. However, incidences of fetal bradycardia following CSE have been reported. This study aimed to identify predictors of fetal bradycardia post CSE, such as a decrease in pain scores, the block height, Prostin (dinoprostone; Pfizer) use, and dosage of oxytocin.


METHODS
From May 2008 to October 2008, 29 patients were identified to have had an episode of fetal bradycardia. Each case was then matched to three controls, according to age and American Society of Anesthesiology status, selected from 2345 parturients who received a CSE during this period.


RESULTS
A unit improvement in the pain score was associated with an increase in the odds of fetal bradycardia by 1.28 (95 % confidence interval [CI]: 1.02-1.60). In a second logistic regression model including sensory level higher than T9, the effect size remained consistent with an odds ratio of 1.22 (95 % CI: 0.97-1.53), supporting the theory that a higher level of sympathetic block (with a higher sensory block taken as a surrogate marker) results in an increased risk of fetal bradycardia. The dosage of oxytocin and the quantity of Prostin used were not found to be risk factors.


CONCLUSIONS
The difference between pre- and post-CSE pain scores, and a higher sensory block height, which are surrogates for a greater degree of sympatholysis, were found to be risk factors for fetal bradycardia post CSE.
Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore. Cheng.sulin@gmail.com
Su Lin Maureen
SL
Cheng
Dianne
D
Bautista
Serene
S
Leo
Tiong Heng Alex
TH
Sia
D000328:Adult; D015360:Analgesia, Epidural; D016362:Analgesia, Obstetrical; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects; D001919:Bradycardia / Q000139:chemically induced / Q000453:epidemiology*; D016022:Case-Control Studies; D005260:Female; D005333:Fetus / Q000502:physiology*; D006340:Heart Rate, Fetal / Q000187:drug effects / Q000502:physiology; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000503:physiopathology; D007231:Infant, Newborn; D010120:Oxytocics; D010121:Oxytocin / Q000008:administration & dosage / Q000627:therapeutic use; D010147:Pain Measurement; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors; D016896:Treatment Outcome
D000779:Anesthetics, Local; D010120:Oxytocics; D010121:Oxytocin