HIGH-FREQUENCY OSCILLATORY VENTILATION - RESCUE TREATMENT FOR INFANTSWITH SEVERE RESPIRATORY-FAILURE

Objective. To assess the efficacy of high-frequency oscillatory ventil ation (HFOV) as a rescue mode of therapy in newborn infants with sever e respiratory failure poorly responsive or unresponsive to conventiona l ventilation and supportive management. Design. Prospective, descript ive clinical study. Setting. Tertiary care neonatal intensive care uni t. Patients and methods. All infants with radiographic evidence of dif fuse bilateral lung disease and failure to maintain adequate blood gas values while receiving conventional support were offered HFOV. Interv ention. HFOV, utilising a high-pressure/volume strategy. Outcome varia bles. Improvement in arterial/alveolar oxygen tension ratio (a/APO(2)) of the infants subsequent to their transferral to HFOV; survival rate ; and outcome of infants weighing more than 2 000 g who met criteria f or extracorporeal membrane oxygenation (ECMO). Identifying the infants who met ECMO entry criteria allowed the success of HFOV to be compare d with that of ECMO, the 'standard' treatment for infants considered u nventilatable. Neonatal complications such as bronchopulmonary dysplas ia, intraventricular haemorrhage and air leaks were documented. Result s. Conventional support failed in 34 consecutive infants; they were tr ansferred to HFOV at a mean postnatal age of 30 hours. Their respirato ry diagnoses included respiratory distress syndrome (RDS) (N = 19), ne onatal ''adult respiratory distress syndrome' (ARDS) (N = 3) and mecon ium aspiration syndrome (MAS) (N = 12). Owing to similarities in the u nderlying pathophysiology, RDS and ARDS were grouped together for;he p urposes of analysis. After starting HFOV the a/APO(2) had significantl y improved (P < 0.05) by 6 hours in the RDS group and by 12 hours in t he infants with MAS. This improvement was sustained throughout the fir st 48 hours of HFOV. Twenty-six (76%) of the infants ultimately surviv ed. Among those who met the criteria for ECMO (N = 13), the survival r ate was 92%. Air leaks occurred on HFOV in 6 infants, 3 each in the MA S and RDS groups. Bronchopulmonary dysplasia was diagnosed in 6 (40%) of the 15 RDS infants and in 2 (18%) of the 11 infants with MAS. Eight infants died, 3 following nosocomial sepsis (Pseudomonas sp.), 3 due to extensive air leaks, 1 due to irreversible shock (unproven sepsis), and 1 due to ARDS. At a median age of 13.5 months the neurological de velopment of 11 (5%) of 17 infants was normal; in 3 (78%) it was suspe ct and in 3 abnormal. Conclusions. The study demonstrates that a high- pressure/volume approach to HFOV is an effective mode of rescue ventil ation for infants who present with severe respiratory failure caused b y a variety of lung conditions during the neonatal period.