2004 OPEN FORUM Abstracts
CASE STUDY COMPARING AIRWAY RELEASE VENTILATION (APRV) TO SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION (SIMV) IN THE CRITICALLY ILL NEONATE
Christina
B. Crooke BS, RRT, NPS, Betty L. Blake BS, RRT, NPS, Susan Aucott
MD. The Johns Hopkins Hospital, Baltimore, Maryland
Introduction:
The critically ill neonate at times requires mechanical ventilation
directed towards multi-system support versus conventional mechanical
ventilation. The use of APRV allows for alveolar recruitment while
minimizing circulatory compromise.
Case
Study: A 32 week neonate presents with tracheoesophageal fistula
and ventricle septal defect. The neonate had an infarct in the right
upper and right middle lobes of the lung which were removed on day of
life (DOL) 38. On DOL 76, the ventilator settings increased to peak
inspiratory pressure (PIP) 28 with positive end expiratory
pressure(PEEP) 7, with no improvement in ventilation and oxygenation.
Mean airway pressure (MAP) in SIMV was 15-16 mmHg. APRV was
initiated using MAP of 25 mmHg. Additional settings included:
pressure high 26, pressure low 2, time high 2.7 with a time low 0.2.
The neonate’s capillary blood gas showed improvement in the
carbon dioxide (CO2)
level and improvement in the SpO2
on lower level on fraction of inspired oxygen (FiO2).
As shown in the table, the patient required less sedation as
ventilatory status improved.
| MODE | FiO2 | TI/TE | END PRESSURE | PEAK | MAP | SPO2 |
| SIMV | .83 | .50/.70 | 7 | 28 | 16 | .94 |
| pH=7.32 | pCO2=87 | PO2=46 | HCO2=43.8 | |||
| APRV | .52 | 2.7/0.2 | 2 | 26 | 25 | .94 |
| Ph=7.43 | pCO2=71 | PO2=47 | HCO2=46.1 | |||
| APRV | .50 | 2.2/0.2 | 2 | 25 | 23 | .94 |
| pH=7.48 | pCO2=39 | PO2=108 | HCO2=28.4 |
Discussion:
APRV uses continuous positive airway pressure levels to maintian
oxygenation and time releases for CO2
removal. APRV allows for unrestricted, spontaneous breathing
throughout the entire ventilatory cycle. Spontaneous breathing
results in better ventilation-perfusion (VA/VQ)
matching which in turn decreases intrapulmonary shunting. Within
hours of initiating APRV the neonate showed marked improvement in
ventilation and oxygenation at lower peak pressures.
Conclusion:
This particular case demonstrates that APRV may have alternative
uses for the neonatal population with poor ventilatory status due to
restrictive lung disease.