Brief Reports

Indian Pediatrics 2002; 39:158-162  

Chronic Lung Disease in Neonates: Emerging Problem in India

From the Division of Neonatology, Department of Pediatrics, Advanced Pediatrics Center, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India.

Correspondence to: Dr. Anil Narang, Professor (Neonatology), Department of Pediatrics, Advanced Pediatrics Center, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India.

E-mail: [email protected]

Manuscript received: April 26, 2000;
Initial review completed: May 20, 2000;
Revision accepted: June 14, 2001.

Northway and collegues, in 1967, first described the clinical, pathological and radiological features of chronic lung disease (CLD)(1). CLD is diagnosed when a neonate has a sustained need for oxygen at or beyond 28 days of life, gestational age not-with-standing(2). In the 1970s, CLD occurred in about 30-40% of infants who received mechanical ventilation(3,4). More recently, the incidence of CLD has apparently enhanced because of increased survival of very low birth weight (VLBW) babies. Among the extremely low birth weight (ELBW) babies the incidence is reported to be close to 60% and it is close to 80% in the babies who required mechanical ventilation for first 3 days of life(5). With the advance-ments in the neonatal intesnsive care, espcially the introduction of better ventilators and surfactant, the survival of VLBW babies has shown improvement in our country in recent times. As a result, the morbidity related to ventilation such as chronic lung disease and retinopathy of prematurity (ROP) are becoming commoner.

Although neonates are being screened for ROP and reported from many centers in our country, there is no publication regarding the magnitude of problems related to CLD. We report our experience of dealing with babies having CLD over a period of 2 years.

This study was conducted on babies born between November 1997 and October 1999 at Neonatal Unit of Nehru Hospital, Post Graduate Institute of Medical Education and Research, Chandigarh. Computerized data-base of the babies with gestational age £32 weeks was analyzed for the occurrence of CLD. Only the babies who survived for ³28 days were included in the study. Detailed case records of the babies who were diagnosed as CLD were reviewed. We included only babies with gestational age of £32 weeks because CLD was rare beyond this gestational age. Chronic lung disease (CLD) was diagnosed when a baby was on oxygen at or beyond 28 days of life, had respiratory distress and chest X-ray was suggestive of CLD, i.e., hyper-inflation, interstitial densities, emphysema and cardiomegaly.

The risk factors for the development of CLD were compared between ‘babies who developed CLD’ and ‘babies who did not develop CLD’ using Chi-square test and Fisher exact test. The differences of mean were compared by analysis of variance. The significant risk factors on univariate analysis were further analyzed using multiple regression analysis.

There were 320 babies £32 weeks gestation who survived for ³28 days; amongst them 108 received mechanical ventilation. There were 19 babies diagnosed to have CLD. (8 of these babies were £28 weeks of gesta-tional age). The incidence of CLD was 5.94% among the babies of £32 weeks. Table I provides the incidence trend in CLD by gestation and birth weight. There was a significant declining trend in CLD incidence as gestation and birth weight increased. CLD was only noted in neonates who were venti-lated, amongst them 19 had hyaline membrane disease and one had congenital pneumonia.

Table II gives the risk factors for CLD. CLD was significantly associated with lower gestation and birth weight; lesser use of antenatal steroids; presence of PDA, septi-cemia or pneumonia; and higher FiO2 and longer duration of ventilation. There was no significant association with use of surfactant or peak inspiratory pressures.

*Chi-square for trend (p <0.001). Figures in parentheses represent percentages.

All babies received aminophylline and diuretic for treatment. Intravenous furose-mide was used in acute phase and it was followed by oral hydrochlorthiazide. Most (94.7%) babies received dexamethasone, which was started between days 15-26 of life and continued for 21-28 days. Salbutamol nebulization was used in the presence of bronchospasm in 31.6% babies. On multiple regression analysis only septicemia, higher concentration of oxygen and longer duration of ventilation were associated with increased incidence of CLD, and full course of antental steroids was associated with lower incidence of CLD.

Thirteen (68.4%) babies with CLD survived till discharge. Four babies died due to septicemia, and one each due to post-hemorrhagic hydrocephalus and intractable respiratory failure. Eyes were examined for retinopathy of prematurity (ROP) in 13 surviving babies and 1 neonate who died. All of them had ROP with 8 having threshold disease requiring laser therapy.

* Odd’s ratio = 0.25(06-0.0.89) 
† Odd’s ratio = 0.97(0.29-3.07) 
‡ Odd’s ratio = 58.3(7.39-1241) 
** Odd’s ratio cannot be determined because incidence of septicemia and pneumonia is 100% among the cases.

Chronic lung disease is a serious disease and is difficult to manage. It carries significant mortality and long-term respiratory morbidity. There is no publication regarding the magnitude of problems related to CLD from our country. In this study the incidence of CLD was 50%, 8.1% and 2.3% among the babies with birth weight <1000 grams, 1000-1249 grams and 1250-1499 grams respectively. The incidence at the centers of the NICHD (National Institute of Child Health and Human Development) neonatal intensive care network was 23.2%, 8.4% and 5.4% among the babies with birth weight <1000 grams, 1000-1249 grams and 1250-1499 grams, respectively(5). Other studies have reported the incidence of CLD as high as 50-60% among the babies with birth weights <1000 grams(6-8). The incidence of CLD in our population is comparable with studies reported from the developed countries.

Prior to this study period, we were diagnosing CLD occasionally. For last 2 years we have observed a significant increase in the occurrence of CLD. This is due to increasing survival of sicker ELBW and VLBW babies. Two major changes have happened at our center during this period - the introduction of better ventilator offering synchronized and patient triggered modes of ventilation and frequent use of surfactant. Forty three per cent of babies with HMD at our center in last 2 years received surfactant. As the babies who are <1250 grams and have severe lung disease have started to survive, the incidence of CLD has increased. Similar observations were reported 10-20 years back from the developed countries. In a study from United States of America, it was observed that the incidence of CLD was 10.6%, 21.7% and 32.9% among VLWB babies during 1976-1980, 1981-1985 and 1986-1990(9).

In our study, we found exposure to higher oxygen concentratioin, longer duration of ventilation, and septicemia as factors promoting the occurrence of CLD and use of antenatal steroids as a factor negatively associated with CLD. Exposure to higher oxygen concentration and longer duration of ventilation are well known risk factors associated with the development of CLD(2). It is well estabished that the use of antenatal steroids decrease the incidence of CLD(10). Atypical organisms like Ureaplasma urea-lyticum have been associated with the development of CLD(11,12). But bacterial sepsis has not been considered as a major risk factor in the development of CLD. There are only few studies, which have tried to correlate bacterial infection and occurrence of CLD. Watterberg et al. showed that the babies born to mothers with chorioamnionitis had increased tendency of developing CLD. They observed increased level of IL-1b on day 1 of life in tracheal lavage fluid and this correlated with increased incidence of CLD(13). Gonzalez et al. observed increased levels of prostaglandin and tumor necrosis factor during sepsis and increased incidence of CLD in these babies. They concluded that infection poten-tiates the risk of CLD(14). The association of bacterial sepsis in our study with CLD is important because of the high incidence of hospital-acquired septicemia in centers across the country.

In summary, chronic lung disease is not a problem only of developed countries. As the number of NICUs is increasing and use of surfactant and better ventilators is becoming more prevalent, we are in for increasing reports of CLD from our country. There is a need for increasing the awareness and we need to evolve management protocols for CLD taking local factors into consideration. The role of bacterial sepsis in the patho-genesis of CLD needs to be evaluated in further detail.

Contributors: AN coordinated the study and helped in the preparation of the manuscript; he will also act as the guarantor for the paper. PK was involved in the data collection and preparation of the manu-script. RK was involved in the data collection, analyzed the data and prepared the manuscript.

Funding: None.

Competing interests: None stated.

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