Effects of combined spinal-epidural analgesia and patient controlled epidural labor analgesia in latent and active phase

Abstract

Objective To compare the effects,stress reaction and concentration of ropivacaine in umbilical cord blood of patients who accepted combined spinal epidural analgesia or patient controlled epidural labor analgesia in latent and active phase.Methods After approved by the ethics committee and informed consents from 80 nulliparous parturients who were admitted to Beijing Friendship Hospital,Capital University of Medical Sciences between January to June 2009,and who were term,single,cephalic presentation delivery and ASA Ⅰ-Ⅱ,were divided into two groups randomly:latent phase group (Group L,cervical dilation 0.5-2.5 cm,n=40) and active phase group (Group A,cervical dilation ≥3.0 cm,n =40).Ropivacaine 2 mg and fentanyl 10 μg was administered in subarachnoid space of all patients.Then,patient controlled epidural infusion of 0.1 ％ ropivacaine plus fentanyl 2 μg/ml were administered.Pain scores (visual analogue score,VAS),lower extremity muscle strength,duration of labor,delivery mode,total dosage used,maternal satisfaction,Apgar score (1 min and 5 min) were evaluated; concentration of ropivacaine (high performance liquid chromategraphy) in cord blood,and concentration of cortisol (radioimmunoassay) in maternal venous blood and cord blood were detected.Forty nulliparous parturients without labor analgesia were taken as control group (Group C).Chi-square test and one way analysis of variance was applied for statistical analysis.Results (1) VAS in Group L and Group A were lower than that of Group C when cervix dilated at 7.0-8.0 cm (2.9± 1.4,2.6± 1.5 vs 9.2±0.7,F=201.50,P＜0.01) and fully dilated (4.7±2.2,3.6±2.0 vs 9.1±0.7,F =-62.07,P＜0.01,respectively).(2) Tbe concentration of cortisol in maternal venous blood right after delivery was higher than that before analgesia in all groups,and the change in group C was significantly greater than that in group L and group A [(902±172) μg/L vs (761±125) μg/L and (731±184) μg/L,t =-3.491 and-3.483,all P＜0.01],moreover there was no significant difference between group L and group A (P＞0.05).There were no difference in cortisol concentration of umbilical blood among the three groups [(168±46) μg/L,(159±49) μg/L and (170±86) μg/L,F=0.23,P＞0.05].(3) There was no difference between ropivacaine concentration in umbilical blood of group L and group A [(0.21±0.10) mg/L vs (0.20±0.03) mg/L,t=0.557,P＞0.05].(4) No significant differences was shown among the three groups in the duration of first and second stage of labor,rate of augmentation,neonatal birth weight,Apgar score at 1 min and 5 min (all P＞0.05).Compared with group C,group L and group A had higher rate of vaginal delivery (52.5％ vs 75.0％ and 85.0％,P＜0.05) and lower rate of cesarean section (45.0％ vs 20.0％ and 15.0％,P＜0.05).The duration of analgesia in group L was longer than that in group A [(215±143) min vs (118±50) min,t =3.722,P＜0.01] and the dosage of fentanyl was also higher [(28± 11) μg vs (17±6) μg,t =5.084,P＜0.01].Conclusions Labor analgesia with combined spinal epidural could decrease cesarean section rate and maternal stress reaction without prolonging the duration of labor and inhibiting neonatal stress reaction.Labor analgesia start from latent phase would not increase the concentration of ropivacaine in cord blood. Key words: Lobor, obstetric; Analgesia, obstetrical; Analgesia, patient-controlled; Anesthesia, epidural; Anesthesia, spinal