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Neonatal Mortality Patterns in a Tertiary Level Neonatal Intensive Care Unit

 

Article By:

A. Shanbhag

K. Sreekumar

M.P. Silveira

 

Abstract

More than a quarter of neonatal deaths all over the globe occur in India.[1,2] The neonatal mortality rate in India has declined from 44 per 1000 live births in 2000 to 29 per 1000 live births in 2012. The objective of the study was to describe the age, weight, and cause specific mortality patterns in newborns admitted in the neonatal intensive care unit (NICU) and to identify the most common causes of mortality according to the duration of life. The findings of the study were that late onset sepsis in all the weight groups was very common stressing the importance of practicing hand hygiene and antibiotic stewardship protocols. Also, birth asphyxia in the very low birth weight (VLBW) and in extremely low birth weight (ELBW) infants point toward the need for increased awareness regarding neonatal resuscitation training amongst residents, doctors, and nurses.

 

Introduction:

More than a quarter of neonatal deaths over the globe occur in India.[1,2] The neonatal mortality rate in India has declined from 44 per 1000 live births in 2000 to 29 per 1000 live births in 2012.[3] However, the rate of decline has been slow and lags behind that of infant mortality rate. Neonatal deaths now account for more than two-thirds of all deaths in the first year of life, out of which major numbers happen in the first week of life. Globally, most neonatal deaths are due to prematurity (36%) infections (23%), asphyxia (23%), and congenital malformations (10%).[3-5] Data on age and cause-specific mortality is important for health planning and specific interventions. While caring for sick newborns, parents and physicians are faced with difficult decisions at various levels of care. Hence, prediction  of  mortality  especially  in extremely low birth weight infants is of utmost importance. Due to the interplay of various demographic and geographical factors contributing to the mortality, it becomes critical to have unit specific predictors of mortality which will help the caretakers to take appropriate decisions.[6-7]

 

Objective:

  1. To describe the age, weight, and cause specific mortality patterns in newborns admitted to the NICU.
  2. To identify the most common causes of mortality according to the duration of life.

 

Material and Method:

This was a retrospective study conducted in the Neonatal Intensive Care Unit of Goa Medical College (Goa) from April 2016 to April 2017. Medical records of all the neonates who expired during the study period were analysed. All the data was classified based on weight, age at time of death, sex, mode and place of delivery, and cause of death. The data was analyzed using SPSS version 20. Correlation between various factors was done using Pearson’s chi square test and the Fisher exact test. A p value of less than 0.05 was considered significant.

 

Results:

During the period of April 2016 to April 2017, there were 1973 babies admitted to the NICU out of which 1343 (68%) were born in this hospital and 630 (32%) were born outside. There were 1112 males (56%) and 861 females (43.6%). Eighty-four babies were extremely low birth weight ELBW (birth weight < 1000 grams), 255 were very low birth weight VLBW (1000-1500 g), 849 were low birth weight LBW (1500-2500 g) and 784 were normal weight (> 2500 g).

A total of 232 neonatal deaths occurred in NICU during the study period. The neonatal mortality rate was 11.7%. The mortality among various categories was born in this hospital: 12.3%; born outside: 10.4%; males: 11.6%, females: 11.9%, ELBW: 70%; VLBW:16.4%; LBW: 7%; and normal birth weight: 9%.

When we studied the mortality group (n=232 babies), the percentage of neonatal deaths among the different weight categories were as follows: < 1000 g: 25.4%, 1000-1500 g: 18.1%, 1500-2500 g: 25.9%, and > 2500 g: 30.6%. In the first 48 hours of life there occurred 23.9% of deaths, 20.8% deaths occurred between days of life 2-7, and 55.3% of deaths occurred after 7 days of life. 74.1% were born by vaginal delivery whereas 25.9% were born by caesarean section. 55.6% were males and 44.4 % were females. Born in this hospital were 71.6% and born in other hospitals was 28.4%.

Among the causes of neonatal mortality, sepsis was found to be the most common cause with an incidence as high as 39.7%. Birth asphyxia and congenital anomalies was seen in 22% and 21.9% of cases respectively. 15.5% of neonatal deaths were attributed to respiratory distress syndrome (RDS).

Among the deaths that occurred within 48 hours of life (n=55), 41.8% were ELBW, 14.5% were VLBW, 29.1% were LBW, and 14.5% were normal weight babies. The above data was correlated using Pearson chi square test and a p value of 0.007 was calculated which suggested a high degree of association between birth weight and age at the time of death. This shows that being an ELBW increases the probability of death within 48 hours.

Within the ELBW group (n=59), it was found that respiratory distress accounted for 63.3% of deaths that occurred in the first 2 days, followed by birth asphyxia in 30.4% cases, sepsis 4.4% and   congenital   anomalies   in   the   rest.  For    ELBW deaths occurring  after 7 days, sepsis was the commonest cause in 80%, followed by RDS in 25.07%.  The significance of the above data was studied with Fisher exact test and a coefficient of 0.001 was obtained, suggestive of a strong significance. This shows that ELBW infants are more prone to late-onset sepsis if they survive beyond 7 days and the most common cause of death in the first 48 hours is birth asphyxia.

Similarly, in the VLBW weight group (n=42), it was found that birth asphyxia and sepsis were the most common cause of deaths and accounted for 37.5% cases each. Sepsis was the most common cause of neonatal deaths occurring after 7 days in 59.4 % cases followed by birth asphyxia in 21.4% cases. The significance of the above data was studied with Fisher exact test and a coefficient of 0.248 was obtained, suggestive of no significance.

In the LBW weight (n=60), birth asphyxia was the most common cause of death occurring within 48 hours and accounted for 68.8% cases, and this was followed by neonatal deaths due to congenital anomalies and genetic malformations in 25.4% cases. Sepsis was the main cause of neonatal deaths occurring within 2-7 days and more than 7 days in 66.7% and 54.4% cases respectively. Babies with congenital anomalies and genetic disorders were the second most common cause of neonatal deaths occurring after 48 hours. This data is consistent with the fact that sepsis is the most common cause of late onset neonatal mortality in the NICU all over the globe. The significance of the above data was studied with Fisher Exact test and a coefficient of 0.004 was obtained indicative of a strong significance. This also suggests that LBW babies would also have intrauterine growth restriction and hence the high incidence of birth asphyxia. Hence improvements in perinatal management of these babies may help to reduce mortality.

In the normal weight (n=71), babies with congenital anomalies and genetic disorders were the most common cause of neonatal deaths occurring within 48 hours and accounted for a major 62.5% cases. Birth asphyxia was the next cause of neonatal mortality in the 48-hour time frame and accounted for 37.5% cases. Among the neonatal deaths occurring within 2-7 days, birth asphyxia accounted in 53.8% cases followed by congenital anomalies and genetic disorders in 38.5% cases. It was also seen that sepsis had a nil contribution to neonatal deaths occurring within 7 days. However, for neonatal deaths occurring after 7 days, sepsis was a dominant factor accounting for 40% cases, closely followed by congenital anomalies and genetic disorders in 36.4% cases. Birth asphyxia only contributed for 22% of neonatal deaths. The significance for the above data was studied using Fisher exact test and a coefficient of 0.004 suggestive of a good significance.

 

Conclusion:

  1. The high mortality of extremely low birth weight babies is still a major concern in our neonatal unit. We need to make all efforts to reduce it. The maximum number of ELBW deaths occur in the first 48 hours and then after seven days. Hence, improved perinatal management and prevention of late onset sepsis would help in reducing mortality.[8,9]
  2. Birth asphyxia is the major reason for mortality in all weight categories within the first 48 hours, hence increased training of personnel in neonatal resuscitation is needed.
  3. Sepsis is the commonest cause of mortality in the bigger babies which means that health-care associated infections and its prevention [10-12] should be taken up in the form of prevention of cross-transmission, barrier nursing and antibiotic stewardship.
  4. Detailed and regular evaluation of unit mortality statistics based on weight, gestation, duration of life, perinatal risk factors, resuscitation, antenatal steroids administration, and other factors should be done to identify risk factors of mortality especially in low birth weight babies.

 

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