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Brief Reports Indian Pediatrics 2000;37: 1251-1255. |
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Delivery Room Management of Neonates Born Through Meconium Stained Amniotic Fluid |
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Meconium aspiration syndrome (MAS) occurs most frequently in term and post term infants who have passed meconium in utero. It causes respiratory morbidity and high mortality ranging from 28-40%(1,3). The current approach to prevent MAS is oropharyngeal suctioning by the obstetrician on delivery of the head followed by immediate postnatal endotracheal suctioning(1,4). However, whether all babies born through thin meconium should undergo immediate postnatal endotracheal suctioning is a point of controversy. The present study was conducted to find out the incidence of MAS in neonates born through Meconium stained amniotic fluid (MSAF) and to evaluate the usefulness of intubation and intratracheal suctioning in vigorous neonates born through thin MSAF.
This study was conducted in the Neonatal Unit, Department of Pediatrics Kasturba Hospital attached to Mahatma Gandhi Institute of Medical Sciences. All deliveries with MSAF were prospectively enrolled in the study and evaluated and managed as per the management protocol (Fig. 1). In addition to routine perinatal data, the consistency of meconium (thick or thin), color of meconium, presence of meconium staining of the cord/skin/nails/vernix, occurrence of respiratory distress and seizure were recorded. Gestation was assessed by last menstrual period (LMP) where known, and correlated with clinical criteria of Dubowitz(s). Where LMP was not known, Dubowitz criteria were used. Those neonates with thin meconium and depression were excluded (one case in whom intubation and intratracheal suction was done had no MAS). Group I consisted of 75 neonates with thick meconium and Group II consisted of 108 apparently vigorous neonates with thin meconium. All study neonates underwent intrapartum suctioning of oropharynx on delivery of head, before the delivery of the shoulders and immediate oropharyngeal suction at birth. Alternate neonates in Group II were assigned to subgroups II-A (no intubation or intratracheal suctioning done) and subgroup II-B (intubation and intratracheal suctioning carried out). Neonates in Group I and in Group II-B underwent chest splinting intuba-tion and direct intratracheal suctioning which was repeated till trachea was cleared of meconium. The following definitions were used:
Statistical analysis was done using Chi-square test and "Z" test. Fig 1. Management Protocol
Table I__Comparison of Baseline and Outcome Variables Between Groups
* P <0.001
Of the 1109 live births, 184 (16.5%) were born through MSAF of which 16 (18.7%) developed MAS bringing the incidence of MAS to 1.44% of all live births. Of the 75 neonates born through thick MSAF, 14 (18.6%) had MAS whereas amongst the 108 born through thin MSAF only 2 (1.8%) had MAS. This difference was statistically significant (p <0.001). Table I compares the baseline variables in the study groups. The mode of delivery did not influence the occurrence of MAS. Cases of thin meconium who underwent intratracheal suctioning (Group II-B) did not show any difference in the development of MAS as compared to cases of thin meconium in whom no intratracheal suctioning was done (Group II- A). There were 2 deaths in Group I due to severe MAS, occurring at 12 h and 4 h after birth, respectively and 1 death in Group II B who had no evidence of asphyxia or MAS at birth and died due to culture proven sepsis on day 6.
Current obstetric and neonatal practices are not able to eliminate MAS which is an important cause of neonatal morbidity and mortality. Moreover, there is no clear consensus regarding management of apparently vigorous babies born through thin meconium. Our incidence of MSAF (16.5%), MAS (8.7%), MAS in all live births (1.44%) and mortality due to MAS of 12.5% falls within the ranges cited by other workers(1,8-11). Meconium passage is rare before 37 weeks but occurs more often in pregnancies of more than 42 weeks of gestation(8). A rising incidence of meconium passage is seen with increasing gestation(10), a finding which was also seen in the present study. MAS can occur even when Caesarian section is done(12) and normal vaginal delivery does not increase the incidence of MAS unless fetal distress is present. In this series, the mode of delivery did not influence the occurrence of MAS. A recent study reported that MAS developed in all babies with severe or moderate asphyxia as opposed to only 41% in those with mild or no asphyxia (1 min Apgar <7)(13). In another study, 33.8% of neonates with asphyxia (1 min Apgar <7) developed MAS(10). In the present study 45.5% of neonates with asphyxia (5 min Apgar <7) had MAS. Thick meconium is associated with increased incidence of MAS, reported as 21%(10) and 35.2%(11). Our incidence was 18.6% whereas the incidence of MAS in thin meconium was reported as 2.9%(10) and 16.1%(11) being 1.8% in the present study. Thin meconium was responsible for 12.4% cases of MAS whereas others report an incidence of 15.4%(10) and 19.4%(11). The consistency of meconium has also a direct bearing on neonatal outcome(10,14) which is borne out by the present study as well. We lost 2 neonates due to MAS, both had thick meconium and severe asphyxia at birth. Asphyxia was more often seen in neonates with thick meconium. There in no consensus about which neonate will be benefited from subsequent intubation and suctioning. Most authors advise intratracheal intubation and suctioning of all meconium stained neonates (3,11,15). Some maintain that intubation should be performed only if heavy, particulate meconium is present(14,16). Finally, others have suggested that if neonate is vigorous and apparently healthy, intubation may not be neces-sary(10,17). Thus it remains unclear whether or not all vigorously active meconium stained neonates should be intubated and suctioned. In the present study we found that the incidence of MAS in vigorously active neonates delivered through thin meconium whether suctioned intratracheally or not was the same. A study stated reduction in the incidence of MAS due to thin meconium from 26% to 16% by combined intrapartum and endotracheal suctioning(11). However, a very well con-ducted recent study concluded that intra-tracheal suctioning of apparently vigorous meconium stained infants does not result in decreased incidence of respiratory distress compared with expectant management (no intubation and intratracheal suctioning)(18). The frequency of adverse complications from intubation procedure appears to be very low. Approximately 1% of intubated infants developed transient stridor(16), whereas only one such incident occurred among several thousand intubated neonates(19). In another study it was found that 2 of 306 intubated infants had persistent stridor(17). A recent study on complications of intubation in vigorous meconium stained neonates found that 3.8% neonates developed mild and transient complications(18). However, in our series no neonate developed stridor or any other complication related to intubation. The present study concludes that thick meconium is more often associated with MAS as compared to thin meconium. Asphyxia is a significant risk factor for the development of MAS in neonates born through MSAF. The outcome of active and vigorous neonates born through thin MSAF is not altered by intubation and suction after birth provided oropharyngeal suction has been done by the obstetrician on delivery of the head. Larger studies are required to prove this point further. Contributors: PC designed, coordinated and interpreted the study and drafted the manuscript. She will act as a guarantor for the paper. BY collected the data and helped in the drafing of the paper. MSB helped in the perception of the study, statistical analysis and revision of the manuscript.
Funding: None.
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