The Science Journal of the American Association for Respiratory Care

2005 OPEN FORUM Abstracts

CASE STUDY: RETROSPECTIVE STUDY OF USING APRV(AIRWAY PRESSURE RELEASE VENTILATION) IN NEONATES WITH OVERWHELMING SEPSIS.

Betty Blake B.S., RRT, NPS, Julianne Perretta B.S., RRT, NPS, Maureen Gilmore, MD. The Johns Hopkins Hospital, Baltimore, Maryland.

Introduction: Four preterm, now near term infants presenting with chronic lung disease (CLD), and sepsis, and respiratory failure. All had worsening respiratory acidosis not responsive to either Pressure Control Ventilation (PCV) or High Frequency Oscillatory Ventilation (HFOV). All were switched to APRV with improvement in respiratory status, sedation management and cardiovascular function.

Case Summary: All four infants were cared for in the Neonatal Intensive Care Unit, a Level IV tertiary care unit, at the Johns Hopkins Hospital. Three of the four neonates were born at 24 weeks gestation. The fourth neonate was born at 30 weeks gestation. At the time of APRV therapy, all four infants were at or near term gestation, ranging from 37- 45 weeks post-conceptional age. All had significant CLD. In addition, each had a history of other complications such as necrotizing enterocolitis, small bowel obstruction, cytomegalovirus infection, or intraventricular hemorrhage. Each of the patients had an infection that caused swelling and severe chest wall edema. The infants developed respiratory failure that became unresponsive to conventional ventilation. All were changed from either HFOV or PCV to APRV. They were started on mean airway pressures (MAP) of 4-12 centimeters water pressure (cmH2O) higher than the MAP set on PCV or HFOV. The peak pressures were able to be decreased by 2 cmH2O. The patients all had improvement in the blood gases, decreased sedation and improved cardiovascular status. As seen in the chart below as respiratory status improved, the amount of sedation decreased and ventilator settings decreased.

Day of APRV Average MAP Average Peak Pressure No. of Daily Sedation Doses
1st day 23.25 25 2
24 hours after initiation 23.5 25.75 1.25
3 days 21.75 22.5 1
7 days 20.6 22.33 0.25

Discussion: All of these patients had some level of chest wall restriction resulting from edema and they had some level of respiratory distress. By placing the patients on APRV we were able to decrease the MAP. The lower MAP led to decreased intrathoracic pressures that aided improved venous return. By allowing the patient to spontaneously breathe we were able to decrease the need for sedation. The spontaneous breathing allowed for improved ventilation-perfusion matching. The spontaneous breathing combined with decreased MAP lead to improved cardiac output.

Conclusion: Although two of the infants died (one from severe CLD, liver failure and cor pulmonale and one had support withdrawn) APRV is a mode of ventilation that has been used safely in the neonatal population. In these near term or term infants, APRV was used effectively and safely. Infants that present with severe CLD and respiratory failure have shown improvement in their status within 3 days of initiation of APRV. Letting the neonate breath spontaneously can allow for better ventilation and perfusion with an improvement in cardiac status and less sedation. This in turn could result in fewer days of mechanical ventilation in an intensive care unit.

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