Effect of induction-delivery and uterine-delivery on apgar scoring of the newborn.
Very short or prolonged induction-delivery interval (i.e. less than 5 minutes or more than 15 minutes) and uterine-delivery interval of more than 90 seconds has a definite effect on the apgar scoring of a newborn especially when general anaesthesia is administered as compared to regional anaesthesia for caesarean section.
Chances of neonatal asphyxia are more in babies born by caesarean section than those delivered per vaginum. These may be related to the anaesthetic techniques employed.
The present study was carried out to determine the effect of anaesthetic techniques viz. general anaesthesia and spinal anaesthesia on the Apgar scoring of newborns in relation to the induction delivery interval and uterine delivery interval.
Hundred and twenty patients undergoing caesarean section were included in the study. They were divided into 2 groups: Group I and Group II.
Patients from Group I (n = 60) had A. S. A. grade 1 and received general anaesthesia. Half an hour after the intra-muscular injection of atropine sulfate (0.5 mg) all the patients were oxygenated for 5 min. and induced with intravenous sodium thiopentone (2.5%) followed by stixamethonium. Endotracheal intubation was carried out. Anaesthesia was maintained with a mixture of oxygen and nitrous oxide and supplemented with intermittent doses of stixamethonium till the delivery of baby. The latter was then substituted by a non-depolarising relaxant, action of which was reversed by neostigmine (0.08 mg/kg) administered along with atropine sulfate (1.2 mg).
Group II comprised 60 patients with A. S. A. grade I who received spinal anaesthesia following atropinization. Lignocaine hydrochloride (5%) was used in these patients to produce subarachinold block.
In both the groups induction-delivery interval [i.e. the time interval from the beginning of induction with anaesthesia (1) to the delivery of the baby (D)] and uterine-delivery interval [i.e. the time interval from the uterine incision (U) to the delivery of the baby (D)] was noted using a stopwatch.
Apgar scoring was done in all the babies at the end of 1, 5 and 10 min respectively. Resuscitation measures, if applied, were also noted.
As shown in [Table - 1], 8 patients from Group I had induction- delivery interval of less than 5 min. Forty patients had an interval between 5 and 15 min. The average interval for the group was 9.3 min. In Group II, none of the patients showed an interval less than 5 min; 34 patients had between 5 and 15 min; the average interval being 15.11 min.
Four patients from each group (7%) had uterine-delivery interval of more than 90 seconds and rest of the cases had less than 90. [Table - 2]) The average for Group 1 was 57 sec (range: 29-92 sec) and for Group II was 68 see (range: 20-91 sec).
Apgar scoring done at the end of 1 min in newborns revealed that 4 patients in Group I had very low scoring (less than-3) as against none from Group 2. Eighteen patients from Group I had scores between 4-6 and 38 had high scoring (between 7 and 10); the corresponding values from Group II being 8 and 52.
All the 4 patients from Group 1, who had uterine-delivery interval of more than 90 sec, had neonates with low to moderate Apgar scores. However the babies of 4 patients from Group II (with uterine-delivery interval of more than 90 -sec) showed high Apgar scoring.
The results of the present study indicate that Apgar scoring done at 1 min was higher in neonates born following caesarean section carried out under spinal anaesthesia as compared to those under general anaesthesia.
A search was carried out to establish the relation of Apgar scoring to induction delivery time in both groups. It was observed that 8 patients from Group I had induction delivery interval of less than 5 min. and six of their neonates had low to moderate Apgar scores. This can be explained on the basis of the anaesthetic agent used. Sodium thiopentone, a thiobarbiturate reaches the foetus in seconds and begins to approach equilibrium between maternal circulation, umbilical vein and artery within 23 min. But as the uterine contractions are absent and cord compression is present in caesarean section, level of drug increases at the onset of anaesthesia and then falls at a rate determined by redistribution combined with maternal and foetal metabolism and excretion. This result in higher levels of barbiturates for shorter induction delivery intervals; and therefore, it has been proposed that induction-delivery interval should be more than 5 min. None of the patients from Group II had induction-delivery interval of less than 5 min and no baby had low Apgar score.
The induction-delivery intervals of more than 15 min were also found to be associated with moderate Apgar scoring. This may be due to higher degree of foetal acidosis as a result of longer duration of anaesthesia, but even in this group, neonates born under spinal anaesthesia showed high Apgar scoring.
The neonates of mothers having uterine delivery interval of more than 90 sec and receiving general anaesthesia showed low to moderate Apgar scoring as against those from Group II. Increase in uterine-delivery interval decreases efficiency of focto-materal exchange resulting in foetal acidosis. The low Apgar scoring at 1 min. may be the result of laryngeal spasm induced by aspiration of liquor or blood during intrauterine manipulation. Patients who receive general anaesthesia have a relatively high level of circulating catecholamines (response evoked by handling the uterus) causing a reduction in placental blood flow, thereby leading to acidosis, the effect of which occurs for prolonged time when uterine-delivery interval increases. As against this, subarachnoid block prevents the local vasoconstrictor response secondary to surgery. This explains the high Apgar scoring in all the 4 neonates of mothers having high uterine-delivery interval but receiving spinal anaesthesia.
Thus, abnormal induction-delivery intervals (< 5 min and > 15 min) and uterine-delivery intervals < 90 sec have less effect on Apgar scoring of neonates of mothers who are administered spinal anaesthesia as compared to general anaesthesia.