Altitude, oxygen and the definition of bronchopulmonary dysplasia.

OBJECTIVE

The definition of bronchopulmonary dysplasia (BPD) among very-low birth weight (VLBW) infants is based upon oxygen requirement at 36 weeks gestation, but oxygen may be required at altitude because of hypoxia. This study determined the effect of altitude on BPD rates.

STUDY DESIGN

For 63 VLBW infants at high altitude, oxygen concentrations were measured by a hood oxygenation test (HOT) and BPD rates were determined with altitude adjustment.

RESULT

BPD rates before and after altitude adjustment were 71.8 and 26.7%, respectively. Of oxygen-dependent infants analyzed by HOT, 33.3% needed room air. HOT oxygen requirement correlated with gestational age of last apnea episode (r=0.42, P<0.001).

CONCLUSION

Although BPD rates may be adjusted for altitude with the HOT, the test does not accurately predict clinical oxygen need. Persistent requirement for supplemental oxygen beyond that needed in the HOT may be partially due to immaturity of respiratory control mechanisms.