Evaluation of the Bird Mark 8 respirator with J circuit for neonatal application

This study presents an evaluation of the Bird Mark 8 Respirator with J Circuit in neonatal application. The system was studied with special attention to the desirability of its possible application in the treatment of a respiratory ailment of newborn infants called hyaline membrane disease.

The project involved the determination of response time of the respirator and blood gas characteristics in rabbits after ventilation by the equipment. Rabbits were used in the experiment because their respiratory behavior resembles that of new-born infants with respiratory distress. The respiration of rabbits was assisted with air supplied to the respirator at 50 p.s.i.

Average response times (minimum of 114 milliseconds, for the case of the rabbit tripping the respirator, with 1 centimeter of water negative pressure in the delivery line), were determined to be in excess of the 20-30 milliseconds maximum limit that may be tolerated by the infant in the treatment of this disease. Blood gas characteristics of the rabbits ventilated for 2 hours with the respirator showed significant increases in the partial pressure of carbon dioxide and significant decreases in the partial pressure of oxygen and pH levels, as compared with the normal blood gas characteristics. These changes are considered undesirable.

From this study it is believed that the respirator does not provide the adequate assistance to respiration required for the treatment of infants afflicted with respiratory distress.