Type of axial analgesia does not influence time to vaginal delivery in a Proportional Hazards Model.
OBJECTIVE
To create a Proportional Hazards Model of prospective factors associated with time-to-vaginal-delivery (TTVD).


METHODS
We analyzed a group of 144 women undergoing childbirth who received one out of two possible axial analgesia techniques, to find-out factors associated with TTVD. The patients were randomly assigned to receive either a levobupivacaine labor epidural (bolus concentration 0.25 % or less; infusion concentration 0.125 % or less) or a combined spinal-epidural procedure (morphine 0.20 mg, fentanyl 25 µg and hyperbaric bupivacaine 2.5 mg as spinal components) for labor analgesia. The factors initially chosen were: mother age, height and weight, parity, gestational age, newborn weight, type of labor, analgesic procedure, levobupivacaine and fentanyl doses, Bromage scale, pain Numeric Rating Scale, and a satisfaction interview. Cesarean section was the censored variable in our model. A systematic multivariate Cox regression was performed.


RESULTS
Our Final Model stated that nulliparous women had 2.5 times more chances of having longer TTVD than primiparous (p < 0.001, CI 1.76-3.8), and 3.4 times more (p = 0.015, CI 1.27-9.25) than multiparous. Women with oxytocin-augmented labor had 2.05 times more chances (p = 0.001, CI 1.31-3.22) of having longer TTVD than patients without oxytocin. An induced partum had 3.8 times more chances (p < 0.001, CI 2.09-6.8) of having longer TTVD compared to a spontaneous partum.


CONCLUSIONS
Parity, labor augmentation, induction of labor and fetal weight determine TTVD; axial analgesia-related factors do not contribute to the model.
Anesthesiology Department, Hospital General de Ciudad Real, SESCAM, C/Besana, 2b, 13170 Miguelturra, Spain. pascrib@hotmail.com
Javier
J
Pascual-Ramírez
Javier
J
Haya
Faustino
F
Pérez-López
Silvia
S
Gil Trujillo
D000293:Adolescent; D000328:Adult; D000767:Anesthesia, Epidural; D000775:Anesthesia, Spinal; D036861:Delivery, Obstetric / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D061646:Operative Time; D011247:Pregnancy; D016016:Proportional Hazards Models; D011446:Prospective Studies; D055815:Young Adult