Predictors of fatality in neonates requiring mechanical ventilation.

OBJECTIVE

To evaluate initial arterial blood gas, pulmonary pressures, pulmonary mechanics (compliance and resistance), pulmonary volumes, oxygenation indices and serum carotenoid levels as predictors of fatality in mechanically ventilated neonates.

DESIGN

Cross Sectional.

SETTING

Referral neonatal unit of a teaching hospital.

SUBJECTS: 83 mechanically ventilated outborn neonates.

METHODS

83 neonates consecutively put on mechanical ventilator from March to December 2001 were enrolled in the study. The mechanical ventilator used was pressure limited time cycled ventilator with facility for online measurement of volumes and pulmonary mechanics. Arterial blood gas after half an hour of initiation of mechanical ventilation and initial pulmonary pressures, pulmonary compliance, resistance and duration of mechanical ventilation were recorded in a pre structured proforma. Initial serum carotenoid levels were also measured using spectrophotometric method. The neonates were regularly followed up for outcome. Multiple logistic regression analysis was done to find out the predictors of fatality for those variables that were significantly associated with outcome on univariate analysis.

RESULTS

On univariate analysis weight ( < 2000 g), gestational age <34 weeks, pH <7.3, duration of mechanical ventilation <72 hours, a/A <0.25, compliance <1 mL/cmH2O, fraction of inspired oxygen (FiO2) >60%, oxygenation index >10, AaDO2 >250 and serum carotenoid levels < 100 microg/dL were significantly associated with fatality in neonates requiring mechanical ventilation. However, on multiple regression analysis only FiO2, gestational age and serum carotenoids < 100 microg/dL were found to be independent predictors of fatality.

CONCLUSIONS

Initial FiO2 > 60%, gestational age <34 weeks and initial serum carotenoid levels < 100 microg/dL were independent predictors of fatality in neonatal mechanical ventilation. Even in a setting with high fatality rates, high risk of mortality in mechanically ventilated neonates can be identified.