High-frequency oscillatory ventilation - Rescue treatment for infants with severe respiratory failure
The original publication is available at http://www.samj.org.za
Objective. To assess the efficacy of high-frequency oscillatory ventilation (HFOV) as a rescue mode of therapy in newborn infants with severe respiratory failure poorly responsive or unresponsive to conventional ventilation and supportive management. Design. Prospective, descriptive clinical study. Setting. Tertiary care neonatal intensive care unit. Patients and methods. All infants with radiographic evidence of diffuse bilateral lung disease and failure to maintain adequate blood gas values while receiving conventional support were offered HFOV. Intervention. HFOV, utilising a high-pressure/volume strategy. Outcome variables. Improvement in arterial/alveolar oxygen tension ratio (a/APO2) of the infants subsequent to their transferral to HFOV; survival rate; and outcome of infants weighing more than 2 000 g who met criteria for extracorporeal membrane oxygenation (ECMO). Identifying the infants who met ECMO entry criteria allowed the success of HFOV to be compared with that of ECMO, the 'standard' treatment for infants considered unventilatable. Neonatal complications such as bronchopulmonary dysplasia, intraventricular haemorrhage and air leaks were documented. Results. Conventional support failed in 34 consecutive infants; they were transferred to HFOV at a mean postnatal age of 30 hours. Their respiratory diagnoses included respiratory distress syndrome (RDS) (N = 19), neonatal 'adult respiratory distress syndrome' (ARDS) (N = 3) and meconium aspiration syndrome (MAS) (N = 12). Owing to similarities in the underlying pathophysiology, RDS and ARDS were grouped together for the purposes of analysis. After starting HFOV the a/APO2 had significantly improved (P < 0.05) by 6 hours in the RDS group and by 12 hours in the infants with MAS. This improvement was sustained throughout the first 48 hours of HFOV. Twenty-six (76%) of the infants ultimately survived. Among those who met the criteria for ECMO (N = 13), the survival rate was 92%. Air leaks occurred on HFOV in 6 infants, 3 each in the MAS 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 development of 11 (5%) of 17 infants was normal; in 3 (18%) it was suspect and in 3 abnormal. Conclusions. The study demonstrates that a high-pressure/volume approach to HFOV is an effective mode of rescue ventilation for infants who present with severe respiratory failure caused by a variety of lung conditions during the neonatal period.
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