Clinical Study Of Preventing And Curing The Hypotension After Combined Spinal-epidural Anesthesia For Cesarean Section.

Aim:To search for a more effective approach to prevent and cure the hypotension after combined spinal-epidural anesthesia for cesarean section by observing and comparing the effect of fluid pre-expansion and prophylactic intravenous vasoactive drugs on the maternal blood pressure,heart rate and PH value of neonatal cord blood in four groups.Methods:80 full-term pregnant women(ASAâ… -â…¡,aged 20-35 years old,there was no obvious difference among their height and weight),undergoing selective cesarean section,who were randomly divided into four groups:namely ephedrine group(group E);phenylephrine group(group P);ephedrine plus phenylephrine group(group EP) and the control group(group C).20 cases in each group. Parturients with twin pregnancy,pregnancy-induced hypertension,cardiac disease,diabetes and other maternal complications were excluded.Oxygen was administered to all parturients via nasal catheters(3L·min^-1) and standard monitors included noninvasive blood pressure device, electrocardiogram and pulse oxygen saturation(SPO₂) after all parturients came into the operation room.The values of maternal blood pressure and heart rate were measured and recorded three times after parturients arrived at the operating room,and the average values of their blood pressure and heart rate were selected as the base values.Upper extremity venous channel was set up by nurse.After an intravenous preload of Hydroxyethyl Starch 130/0.4 (10ml·kg^-1) in 30 min,spinal-epidural anesthesia was performed at L_3-4 interspace with parturient on left-lateral position.After spinal puncture was finished,the mixture of 0.64% bupivacaine and 7.5%glucose(50%glucose 0.3ml plus 0.75%bupivacaine 1.7ml) 1.6ml was injected through the spinal needle,and epidural catheter were placed 3.5cm cephalad,then let parturient take the left-tilted 30 degrees supine position.When spinal anesthesia drug was given, vasoactive drugs or placebo were simultaneously injected intravenously[Ephedrine 10mg in group E;Phenylephrine 100μg in group P;Ephedrine 5mg plus phenylephrine 50μg in group EP and the same amount of normal saline(5ml) in group C].Lactated Ringer's solution was given continuously by intravenous catheter during all the operating programme.When the systolic blood pressure(SBP) was lower than 20%basic value,if HR was above 100 bits·min^-1, phenylephrine 50μg was intravenously given;if HR was below 100 bits·min^-1,intravenous ephedrine 5mg was used as a remedial measure in order to maintain BP and HR at the normal range.The values of BP and HR were monitored and recorded at 1min,3min,5min,10min, 15min,20min,25min and 30min after spinal anesthesia drug was given.The PH value of neonatal cord blood and the Apgar score of the neonate were detected immediately after neonate was born.At the end of the operation,the cumulative doses of ephedrine and phenylephrine,and the incidences of nausea and vomiting of the parturients during the operation were recorded;the satisfactions of surgeons and parturients to anesthesia were also inquired and recorded.Results: The incidences of maternal hypotension,nausea and vomiting,and the total volume of vasoactive drugs in group EP were significantly lower than those of the other three groups(P＜0.05);the values of the maternal heart rate in group EP and in group P at 3min,5min,10min, 15min,20min and 25min were markedly lower than those in group C and in group E(P＜0.05); The satisfactions of surgeons and parturients in group C to anesthesia were significantly lower than those of the other three groups(P＜0.05);the PH value of umbilical cord blood of the neonates in group EP was obviously higher than those in group E and in group C(P＜0.05),but lower than that in group P(P＜0.05);There was no distinct difference among four groups on neonatal Apgar score at 1min and 5min after neonates were born(P＞0.05).Conclusion:The fluid preloading and prophylactic intravenous injection of ephedrine plus phenylephrine can markedly reduce the incidence of maternal hypotension after CSEA for caesarean section, therefore decrease the adverse effects of maternal hypotension on parturient and fetus;it is an ideal method for preventment and treatment of the hypotension after subarachnoid anesthesia, can be safely used for cesarean section with spinal anesthesia.