Dear Editor,

Teford et al(1), have done a remarkable job of recruiting 65% of the original cohort of the Continuous Negative Extra thoracic Pressure (CNEP) study at 9.6-14.9 yrs of age.However their conclusion that there is no long term benefit of CNEP needs to be qualified.

In the original paper benefits were only moderate. There was no improvement in the mortality but a small reduction in the incidence of BPD that came down from 32% in control group to 20% in CNEP group(2). Most other parameters were not statistically different. It is well known that patient with BPD have higher respiratory morbidity in terms of reactive airway disease, pneumonia, and brochiolitis(3,4,5). So we can expect the cluster with BPD to have a higher number of respiratory problems later.

In the present follow-up study 65% of patients followed up. It would be important to know how many of the original cases with BPD in earlier study were included in the present follow-up study. It is possible that selection bias may have included more non BPD cases and under those circumstances the absence of significant difference is not unexpected.

We hope the author can specify if all the cases of BPD in the original study were followed up.

References:

1) K Telford, L Water, H Vyas, B N Manktelow, E S Draper, N Marlow, Raspiratory outcome in late childhood after neonatal continuous negative pressure ventilation. Arch Dis Chil Fetal Neonatal Ed 2007;92;F19-F24.

2) Martin P Samuels, Joseph Raine, Theresa Wright, John A. Alexander, Kate Lockyer, S. Andrew Spencer, David S. Brookfield, Neema Modi, David Harvey, Carl Bose and David P Southall; Continuous Negative Extrathoracic Pressure in Neonatal Respiratory Failure; Pediatrics 1996;98;1154-1160

2) Howandi M, Rajah J, Abushrar Z, Parsons H. The severity of respiratory syncytial virus bronchiolitis in young infants in the United Arab Emirates, J Trop Pediatr. 2007;53:22-6. Epub 2006 Sep 28

3) Bhandari A, Panitch HB, Pulmonary outcomes in bronchopulmonary dysplasia. Semin Perinatol. 2006 ;30:219-26.

4) Flamant C, Hallalel F, Nolent P, Chevalier JY, Renolleau S, Severe respiratory syncytial virus bronchiolitis in children: from short mechanical ventilation to extracorporeal membrane oxygenation. Eur J Pediatr. 2005 ;164:93-8. Epub 2004 Nov 25.