PURPOSE:In spite of surfactant therapy, bronchopulmonary dysplasia (BPD) remains frequent. A major contributor to this complication is the persistent need, notwithstanding normalized lung mechanics, for respiratory support by invasive positive pressure ventilation(IPPV). Biphasic Cuirass Ventilation (BCV), a non invasive form of respiratory support could thus be an advantageous alternative.Our purpose was to compare efficacy of BCV to IPPV in terms of gas exchange, stability of pulmonary mechanics and hemodynamic status.
METHODS:Anesthetized paralyzed neonatal piglets (age: 2–17 days) were randomized to 5 hours ventilation by IPPV or BCV. For IPPV, a pressure and time cycled ventilator delivered a tidal volume of 11 ±.4 ml/kg at 16 ± 5 cm H20 of peak inspiratory pressure. For BCV, a loose fitting tightly sealed plastic cuirass attached to a programmable power unit (HAYEK RTX Respirator, Medivent), enclosed the chest and abdomen. Inspiratory and expiratory cuirass pressures were -19 ± 2 and + 5 cm H20 respectively. For both ventilation modes, Fi02, tracheal expiratory pressure (PEEP/CPAP) and rate were .4, 5 cm H 20 and 40–60 breaths/min respectively. Arterial and venous gases, cardiac output, systemic and pulmonary vascular pressures and carotid blood flow were measured hourly. From the above were derived systemic and cerebral oxygen extraction. Lung volumes were measured by Helium dilution.
RESULTS:Gas exchange and pulmonary mechanics at baseline and after 5 hours(end) of ventilation are shown in Table 1. Indices of systemic and cerebral blood flow remained similar at the end of each mode of ventilation.
CONCLUSION:Hemodynamic status and gas exchange were similar for both modes of ventilation. The mild decline in lung volume associated with prolonged ventilation in paralyzed animals was accentuated during BCV. CPAP associated to BCV maintained expiratory lung volume above FRC.
CLINICAL IMPLICATIONS:The use of non invasive biphasic cuirass ventilation may be feasible in preterm infants.Its use may become an alternative for invasive positive pressure ventilation and thus enable a reduction of the frequency of chronic lung disease in preterm infants.
DISCLOSURE:Fabien Eyal, None.