Use of Orotracheal CPAP ( Gregory System) for Treatment of Respiratory Failure in Newborns

Recent advances in the intensive care of the newborns are closely related to the evolution in the management of the respiratory distress syndrome (RDS) frequently associated with lung immaturity specially in the premature infant as well as with various pathological conditions in the mature lung of the full- term baby. The methods of ventilatory assistance to treat these conditions vary from continuous positive airway pressure (CPAP) to conventional mechanical ventilation and/or high frequency ventilation. It is reasonable to assume that the type of ventilatory assistance provided to these infants should be graded in accordance to the severity of the respiratory problem (1) therefore the mode of respiratory support should be one which while providing adequate ventilatory assistance will result in minimal volu or barotrauma.

Currently the investigators know that the best ventilatory technique is one that stabilizes Po2, Pco2 and Ph and avoids volu and barotrauma, diminishes the possibility of pulmonary injury and shortens the time spent in the hospital.

It has been demonstrated that with the use of CPAP the need for mechanical ventilation is less and that the possibility of pulmonary injury and the length of hospital stay are shortened (1 ) ( 2). The need to use mechanical ventilation increases when gestational age is marginal or in the presence of severe pulmonary pathology that causes increased respiratory problems which in turn enhances the possibility of increase the alveolar oxygen tension gradient (A-a DO2) to more then 180mmHg and to cause the presence of a more severe hyaline membrane syndrome as evidenced by sequential chest X rays (8). This also will limit the need for early nasal continuous airway pressure (ENCPAP). Other limiting factors could be pressure changes due to physiological events such as cry, mouth open or close, cough or hippus. In the past use CPAP generated by the ventilator administered via an endotracheal cannula ; however this method of ventilation has been abandoned due to the high risk of barotrauma due to the surges of pression in a closed, rigid, system that could eventually generate an increased resistance due to the disparity between the caliber of the endotracheal tube and that of the trachea (9). This increased resistance was for a long time considered to be a great limiting risk for the use of orotracheal CPAP particularly in premature infants.

According with the severity of the disease, the best results have been obtained with the use of low pressure, high pulmonary volumes such as those provided by high frequency oscillatory ventilation (HFOV) or conventional ventilation with a high positive end expiration pressure (PEEP) (1).

The investigators want determinate the rate of pneumothorax , use of oxygen at 36 weeks of gestational age , failure to treatment, mortality , infection rate an other complications with the 3 methods for assisted ventilation.