The effects of propanidid and thiopentone on the acidbase status of babies delivered by elective Caesarean section have been compared. The only significant difference between the 2 groups was the lower umbilical cord venous blood pCO) levels in the propanidid group. The acid-base status in both these groups of babies was not as good as in those delivered after induction delivery times of less than 6 minutes when thiopentone had been used as the induction agent. The clinical state of the babies in the propanidid group was superior to that in the thiopentone group, and at least equal to that of the group with the short induction-delivery interval.S. Afr. Med. J., 48, 1019 (1974

Bond, RA

Fothergill, RJ

Robertson, A

English

The effects of propanidid and thiopentone on the acid-base tatus of babies delivered by elective Caesarean section have been compared. The only significant difference between the 2 groups was the lower umbilical cord venous blood pCO2 levels in the propanidid group. The acid-base status in both these groups of babies was not as good as in those delivered after induction-delivery times of less than 6 minutes when thiopentone had been used as the induction agent. The clinical state of the babies in the propanidid group was superior to that in the thiopentone group, and at least equal to that of the group with the short induction-delivery interval.S. Afr. Med. J., 48, 1019 (1974)

Robertson, A.

Fothergill, R.J.

Bond, R.A.

AJOL - African Journals Online

18 Mei 1974 S.-A. MEDIESE TYDSKRIF 1019Effects of Propanidid and Thiopentone on theAcid-Base Status of Babies Delivered by ElectiveCaesarean SectionA. ROBERTSON, R. J. FOTIIERGILL, R. A. B01\TJ)SUMMARYThe effects of propanidid and thiopentone on the acid-base status of babies delivered by elective Caesareansection have been compared. The only significantdifference between the 2 groups was the lower umbilicalcord venous blood pCO) levels in the propanidid group.The acid-base status in both these groups of babieswas not as good as in those delivered after induction-delivery times of less than 6 minutes when thiopentonehad been used as the induction agent.The clinical state of the babies in the propanidid groupwas superior to that in the thiopentone group, and at leastequal to that of the group with the short induction-deliveryinterval.5. Air. Med. J., 48, 1019 (1974).In a previous publication' we showed that babies deliveredby elective Caesarean section after prolonged anaesthesiawere more acidaemic than those delivered after an in-duction-delivery interval of less than 6 minutes. Sincethen we have shown that the elevation of maternal pO,at the time of delivery has had a mild but not markedeffect on the acid-base and clinical state of the baby.Although there was less neonataI acidaemia in thesecases the acid-base status of the babies was not as goodas in those babies delivered after a short period of anaes-thesia.This anicle is a further attempt to find a method ofanaesthesia which, despite a prolonged induction-deliveryinterval, will give results that are as good as those we havefound with a very short induction-delivery interval.Baraka et al.' have shown the beneficial effects of pro-panidid on the clinical state of the neonate, aDd Bradfordand Moil"" have suggested that propanidid is no worse andmay even be superior to thiopentone in regard to the con-dition of the neonate after Caesarean section. S6der' con-Good Hope Maternity Hospital, Sutton Coldfield, Wanvick-shire, EnglandA. ROBERTSON, She/don Research Fellow (Present address:Department of Obstetrics and Gynaecology, University ofRhodesia, Salisbury, Rhodesia)R. J. FOTHERGILL, Consllltant GynaecologistR. A. BOND, Consultant AnaesthetistDate received: 7 January 1974.Reprint requests to: Dr A. Rohertson. Department of Obstetrics andGynaecology, University of Rhodesia, Salisbury, Rhodesia.13siders propanidid to be the drug of choice for obstetricalanaesthesia; but K6lliker5 did not find any significant ad-vantage over thiopentone, as far as the condition of theneonate was concerned. All these authors judged theirresults on the clinical state of the babies at delivery, andto our knowledge no-one has compared the effect on theacid-base status of babies delivered at elective Caesareansection in which the two drugs were used. Downing andColeman' recently made a plea for more detailed studiesof propanidid in elective Caesarean section, including ananalysis of maternal and fetal blood gas and acid-basestatus.METHODSThe series consisted of 27 patients undergoing electiveCaesarean section. They were divided into 3 groups:1. The 'fast' group (delivery within 6 minutes of lll-duction of anaesthesia-9 babies).2. The 'slow' group (delivery between 16 and 42minutes from induction-9 babies).3. A 'propanidid' group (delivery between 16 and 36minutes from induction in 7 cases and in 2 only 10 and11 minutes-9 babies).The method of anaesthesia for the propanidid group wasidentical with that of the slow group in all respects exceptthat propanidid was used to induce anaesthesia in pre-ference to thiopentone-the technique of anaesthesia is fullydescribed in an earlier paper.' The usual dose of thiopen-tone varied between 200 and 250 mg, but 300 mg wasgiven in one case. The dose of propanidid varied between300 and 500 mg.The indications for Caesarean section and the ages andparity of the patients were fully comparable in the 3groups. Of the 27 patients, 12 fell into the class definedby Crawford' as group A. Of these, 3 were in the fast,4 in the slow and 5 in the propanidid groups. All but 4of the babies weighed more than 3 kg. In the slow group3 babies weighed between 2,85 and 2,95 kg and 1 in thepropanidid group weighed 2,38 kg at 38 weeks' gestation,and were therefore light-for-dates (under the 10th per-centile of birthweight for gestation as definedS). The surgi-cal technique was virtually identical in all cases.The blood samples were taken from the hyperaemicmaternal finger-tip at the time of delivery and from aloop of cord clamped immediately after delivery. The1020 S.A. MEDICAL JOURNAL ]8 May ]974samples were obtained and examined in the manner des-cribed previously.'The resident paediatric medical officer examined eachbaby at delivery and made a completely independentassessment of the Apgar scores at 1 and 5 minutes afterdelivery. The 2 points usually allocated for the colour ofthe baby have been omitted and the scores stated are outof a total of 8 points (Apgar minus colour).RESULTSThe measurements (means and standard deviations) ob-tained from the maternal capi1Jary blood and the cordarterial and venous blood in the fast and slow and pro-panidid groups are shown in Table I. The statistical sig-nificance of the differences between the means of theresults in the different groups using an analysis of variancetechnique is shown in Tables I1, III and IV. Table V showsthe coefficients of linear correlation between the individualresults and the induction-delivery times for all cases in theseries.pH ValueThe mean maternal capillary blood pH at the time ofdelivery in the proparudid group was 7,47 and tills doesnot differ significantly from that of either the fast or slowgroups. The mean cord arterial pH in the propanidid group.TABLE I. MEAN VALUES OF MATERNAL CAPILLARY BLOOD AT DELIVERY, CORD ARTERIAL AND CORD VENOUSBLOOD IN THE FAST, SLOW AND PROPANIDID GROUPS(THE STANDARD DEVIATIONS ARE SHOWN IN BRACKETS UNDERNEATH)Standard OxygenpC02 Base excess bicarbonate p0 2 saturationpH (units) (mmHg) (mEqjL) (mEqjL) (mmHg) (%)r Maternal capillary blood 7,46 21,9 -6,4 19,6 100,6 95,9j(0,07) ( 5,6) (2,9) (2,1) (41,7) ( 3,8)Fast Umbilical cord arterial blood 7,33 38,0 -5,6 20,1 21,9 49,9group (0,03) ( 7,0) (2,1) (1,7) ( 8,6) (22,2)Umbilical cord venous blood 7,33 38,4 -5,7 20,0 29,7 62,4I(0,06) ( 5,8) (1,7) (1,3) ( 9,5) (15,6)Maternal capillary blood 7,41 27,6 -6,2 19,7 67,2 87,1(0,09) ( 6,6) (2,0) (1,5) (20,6) (19,9)Slow Umbilical cord arterial blood 7,22 52,2 -7,5 18,8 16,2 31,89rouP (0,07) (10,9) (4,7) (3,3) (13,1) (20,8)Umbilical cord venous blood 7,25 50,3 -6,7 19,4 22,1 43,4(0,06) (10,0) (3,3) (2,4) ( 9,3) (18,8)r Maternal capillary blood 7,47 20,7 -7,3 19,1 72,9 91,1j(0,10) ( 8,6) (3,6) (2,6) (25,1) (11,0)Propanidid Umbilical cord arterial blood 7,26 48,7 -5,9 20,1 13,2 27,1group (0,09) ( 7,0) (4,9) (3,5) ( 5,0) (12,0)Umbilical cord venous blood 7,30 42,4 -5,8 20,1 19,9 41,6(0,24) ( 7,2) (4,2) (3,0) ( 4,7) (16,9)TABLE 11. STATISTICAL SIGNIFICANCE OF THE DIFFERENCES BETWEEN THE MEANS OF THE RESULTS IN THESLOW AND PROPANIDID GROUPSBase Standard OxygenpH pC02 excess bicarbonate p0 2 saturationMaternal capillary blood at delivery NS NS NS NS NS NSUmbilical cord arterial blood NS NS NS NS NS NSUmbilical cord venous blood NS <0,05 NS NS NS NSTABLE Ill. STATISTICAL SIGNIFICANCE OF THE DIFFERENCES BETWEEN THE MEANS OF THE RESULTS IN THE FASTAND PROPANIDID GROUPSBase StandardpH pC02 excess bicarbonate p0 2Maternal capillary bk'od at delivery NS NS NS NS NSUmbilical cord arterial blood <0,01 <0,01 NS NS NSUmbilical cord venous blood NS NS NS NS <0,01OxygensaturationNS<0,01<0,0118 Mei 1974 S.-A. MEDIESE TYDSKRIF 102\TABLE IV. STATISTICAL SIGNIFICANCE OF THE DIFFERENCES BETWEEN THE MEANS OF THE RESULTS IN THE SLOWAND FAST GROUPSMaternal capillary blood at deliveryUmbilical cord arterial bloodUmbilical cord venous bloodpHNS<0,01NSBase Standard OxygenpCOz excess bicarbonate pOz saturationNS NS NS NS NS<0,01 NS NS NS <0,05<0,01 NS NS NS <0,05of 7,26 (if the light-for-dates baby is omitted the meanbecomes 7,28) is higher than the mean of the slow group(7,22), but this difference is not statistically significant.The mean of the fast group is significantly higher thanthat of the slow and the propanidid groups (both P<O,Ol).The mean cord venous pH is highest in the fast group(7,33) and lowest in the slow group (7,25), but the differencebetween the means of the different groups is not signifi-cant.Partial Pressure of Carbon DioxideThe mean maternal capillary blood pea, was lower inthe fast and propanidid groups but these means were notsignificantly different from the mean of the slow group.The mean cord arterial pCO, of the fast group was sig-nificantly less (P<O,Ol) than the slow and propanididgroups, but the differences between the means of the slowand propanidid groups were not significant. The mean cordvenous pCO, was lower in the fast group than in the other2 groups and the difference between the means of theslow and fast groups and the slow and propanidid groupsis significant (P<O,OI and P<0,05, respectively). Thedifference between the means of the fast and propanididgroups is not significant.Base Excess and Standard BicarbonateThe differences between the mean maternal and cordbase excess and standard bicarbonate values in the 3groups are not statistically significant.Partial Pressure of OxygenThe mean maternal and cord pO, levels were higher inthe fast group than in the other 2 groups, but the onlystatistically significant difference between the means ofthe different groups was that where the cord venous pO,of the propanidid group was significantly less than thatof the fast group (P<O,OI).Oxygen SaturationThere is no statistically significant difference between themean maternal capillary blood oxygen saturation levels ofthe 3 groups. The mean cord arterial oxygen saturationwas higher in the fast group than in the other 2 groupsand it was lowest in the propanidid group. The differencebetween the mean of the fast group and those of the slowand propanidid groups is significant (P<0,05 and P<O,OI,respectively), but again there is no significant differencebetween the mean of the slow group and that of the pro-panidid group. Similarly, the mean cord venous oxygensaturation was highest in the fast group and lowest in thepropanidid group. The difference between the mean cordvenous oxygen saturation levels' of the slow and propanididgroups is again not significant but the mean of the fastgroup is significantly higher than that of the slow group(P<0,05) and that of the propanidid group (P<O,Ol).Table V shows that the induction-delivery times for allcases correlate with the cord arterial and venous pH(r = -0,85 and -0,65), pCO, (r = +0,65 and +Q,50) andto a lesser extent with the base excess (r = +0,41 and-0,40) and standard bicarbonate (r = -0,40 and -0,31).The maternal pCO, correlated with the induction-deliverytime (r = + 0,43) but the pO, and the oxygen saturationdid not.The Apgar minus colour scores were equally favourablein the fast and propanidid groups and in both of thesegroups they were superior to those of the slow group. At5 minutes all 9 babies in the propanidid group had scoresof 8. All babies in the series were alive and well at latereview.BleedingOnly I case in the series required a blood transfusionand this patient was given 2 units of blood.TABLE V. COEFFICIENTS OF LINEAR CORRELATION BETWEEN THE INDIVIDUAL RESULTS AND THE INDUCTION-DELIVERY TIMES FOR ALL CASESBase Standard OxygenpH pCOz excess bicarbonate pOz saturationMaternal capillary blood -0,32 +0,43 -0,06 +0,04 -0,36 -0,17Umbilical cord arterial blood -0,85 +0,65 +0,41 -0,40 -0,11 -0,29Umbilical cord venous blood -0,65 +0,50 +0,35 -0,31 -0,14 -0,24141022 S.A. MEDICAL JOURNAL 18 May 1974DISCUSSIONOthers'·3 have shown that propaniclid used to induceanaesthesia at elective Caesarean section results in thedelivery of babies in better clinical condition than in thosecases where anaesthesia was induced with sodium thio-pentone. The present series was designed to compare theeffect of these drugs on the acid-base status of babiesdelivered by elective Caesarean section.The only statistically significant difference in the cordblood values between the slow and propanidid groups wasthat the cord venous pCO, was lower in the latter group.Although the mean cord arterial pCO, in the propanididgroup was less than that of the slow group, the differencewas not statistically significant. The lowered cord venouspCO, may be explained by the fact that propanidid causesthe mother to hyperventilate initially and so reduce herpCO, level. This did in fact happen in this series, themean maternal pCO, in the propanidid group being lowereven than that of the fast group. Although the differencebetween the mean maternal pCO, of the slow and pro-panidid groups is not significant, it is this difference whichprobably resulted in the significantly lower mean pCO,values in the cord venous blood of the propanidid groupcompared with that of the slow group. There are no otherstatistically significant differences between the differentacid-base values of the slow and propanidid groups.although it will be noted that. while not statistically signifi-cant. the mean cord arterial and venous pO, and oxygensaturation levels are even lower in the propanidid groupthan in the slow group.The babies in the propanidid group did not achieve thegood acid-base status of those in the fast group. The cordarterial pH was significantly higher (P<O,Ol). the pCO,was significantly lower (P<O,OI) and the cord arterialoxygen saturation was significantly higher (P<O,Ol) in thefast group than in the propanidid group. The.cord venouspO, and oxygen saturation were also significantly higher(P<O,OI and P<O,OI) in the fast group than in the pro-p:midid group.Although the babies in the propanidid group did nothave as good acid-base status or oxygen levels as those inthe fast group, their clinical state, as judged by Apgarminus colour scores, was equal if not superior to that ofthe fast group. Baraka' explains the better clinical state ofthe baby when propaniclid has been used by the fact thatthe drug itself is rapidly hydrolysed by esterases in thebody to form pharmacologically inert products. Bothmaternal and fetal blood levels of propanidid are neg-ligible within 3 - 4 minutes of intravenous injection tothe mother.9 Cholinesterase is also present in large quanti-ties in placental tissues and could play a part in the break·down of propanidid, thus minimising the concentration ofpropanidid reaching the fetus.]·Unlike propanidid, thiopentone undergoes metabolicdegradation in the liver very slowly. It is ·known to crossthe placental barrier within 45 seconds of intravenousadministration to the mother and to attain a maximumconcentration in the fetus after 2 - 3 minutes. Barakaconsiders that when thiopentone is used as an inductionagent for nitrous oxide anaesthesia, the latent depressanteffect becomes manifest particularly if the induction-delivery time is prolonged. Marx et al." have shown thatthe umbilical artery-vein nitrous oxide concentration ratiowhich parallels the fetal uptake of nitrous oxide increasesprogressively with increasing duration of anaesthesia. Asthe induction-delivery time is prolonged, the brain con-centration of nitrous oxide is built up and might summatewith the residual effect of thiopentone, resulting in a highincidence of neonatal depression.This series also confirms our earlier work] and showsthat the acid-base and clinical state of the neonate de-livered by elective Caesarean section deteriorate with theprolongation of the induction-delivery time.CONCLUSIONPropanidid, used as an induction agent for anaesthesiafor Caesarean section, is probably preferable to thiopen-tone. Although it produces very little improvement in theacid-base status of the babies delivered, the clinical statewas markedly better than that in the thiopentone groupwhen the induction-delivery time was prolonged.The beneficial effect of propanidid may be due to rapidhydrolysis; initial maternal hyperventilation; or the lessertoxic effects than thiopentone has on the central nervoussystem of the neonate.We wish to thank Messrs W. S. Crawford and C. W.Mortimer for allowing us to include their patients, Dr W.Castle and Miss I. A. Edmonstone for statistical help, andthe Birmingham Regional Hospital Board for financial assis-tance.REFERENCES1. Folhergill, R. J .• Rober~son, A. and Bond, R. A. (1971): J. Obstet.Gynaee. Bn!. CWlth, 78, 1010.2. Baraka, A .. O'Brien, M., Aslanian, E. and Saade, R. (1971): Brit. J.Anaesth., 43, 609.3. Bradford, E. M. W. and Moir, D. D. (1969): Ibid., 41, 274.4. SOder, G. (1970): Acta anaesth. seand., suppl. 37. p. 225.5. Kolliker, K. (1970): Ibid., suppl. 37, p. 220.6. g~;ning, 1. W. and Coleman, A. J. (1973): S. Afr. Med. J., 47,7. Crawford. J. S. (1965): Pril/ciples aI/cl Praclice 0/ Obstetric AI/aes-lhesia, 2nd cd. Oxford: Blaekwell.8. Thomson. A. M., Billewiez. W. Z. and Hytlen. F. E. (1968): J.Obstet. Gynaee. Brit. Cwlth, 75, 903.9. Doenieke, A., Krumey, I., Kugler. J. and Klempa, J. (1968)':Brit. J. Anaesth., 40, 415.10. Crawford, J. S. (1968): Ibid., 40, 713.11. Man, G. F., Joshi, G. W. and Orkin, L. R. (1970): Anesthesiology,32, 429.'.

Effects of propanidid and thiopentone on the acid-base status of babies delivered by elective caesarean section

Effects of Propanidid and Thiopentone on the Acid-Base Status of Babies Delivered by Elective Caesarean Section

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Effects of Propanidid and Thiopentone on the Acid-Base Status of Babies Delivered by Elective Caesarean Section

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