2004 OPEN FORUM Abstracts
NASAL HIGH FREQUENCY VENTILATION AS TREATMENT FOR EXTUBATION FAILURE IN A PRETERM INFANT
Michael
Tracy, BS, RRT-NPS, Timothy Myers BS, RRT-NPS, Robert Chatburn
RRT-FARC, Ricardo Rodriguez, MD, Rainbow Babies & Children’s
Hospital / Case Western Reserve University, Cleveland, Ohio
INTRODUCTION:Nasal continuous positive airway pressure (NCPAP) is currently the
neonatal standard of care for supporting and augmenting spontaneous
respiration in the immediate post-extubation period. Non-Invasive
positive pressure ventilation (NIPPV) is an option worth
consideration. The Cochane Review (The Cochrane Library, Issue 4,
2003) concluded NIPPV superior to NCPAP in preventing extubation
failure in preterm neonates. In a separate study, van der Hoeven et
al (Arch Dis Child Fetal Neonatal Ed 1998) effectively
treated 21 infants with moderate respiratory insufficiency with nasal
high frequency ventilation (NHFV).
CASE
SUMMARY: A 34 5/7 week, 1.7
kilogram infant with RDS, IUGR, DORV, (s/p balloon valvuloplasty for
pulmonic stenosis) and micrognathia was intubated on DOL 1 and given
Survanta. The patient was extubated to NCPAP on DOL 14 from minimal
ventilator settings. Over the next month, the patient was
reintubated four additional times secondary to extubation failure for
significant atelectasis, and increases of FIO2 (≥
0.60), respiratory rate and work of breathing. Chest films (CXR)
demonstrated complete left side atelectasis and right-sided patchy
infiltrates. After discussion with the neonatal attending, NHFV was
selected as an alternative to reintubation. NHFV was initiated with
the Infant Star 950 (Infrasonics San Diego,
CA) at mean airway pressure 8 cmH20 (NCPAP level),
frequency of 6 Hz, ∆ P = 32 cmH20 (established by
adequate chest wiggle) and FIO2 = 0.60 (CPAP FIO2).
After 12 hours of NHFV, the CXR showed the left hemi-thorax almost
completely re-expanded with some right upper lobe collapse. NHFV
support continued without attempts to wean the settings. After 81
hours of therapy, NHFV was discontinued and the infant was placed on
NCPAP +6 cmH20 and an FIO2 0.28. NCPAP and
FIO2 were weaned over the next two weeks and the patient
was discharged from NICU without further pulmonary complications.
DISCUSSION:NHFV was chosen over NSIMV due to the (1) significant difference
found in hemithorax compliance, (2) lack of dead space ventilation
concerns and (3) lack of need to synchronized NSIMV with patient
spontaneous efforts. The oscillations of NHFV typically attenuate
upon entry to the patient interface device. Therefore; titration of
the ∆ P to achieve adequate chest wiggle, regardless of numeric
value, should overcome signal attenuation. Our patient’s
results for NHFV therapy duration (81 hours) are comparable to those
found by van der Hoeven’s (mean 40 hours, range 17 – 126
hrs). Our patient was able to sustain spontaneous minute ventilation
without a need to manipulate NHFV settings (pH 7.32 – 7.36, CO2
45 – 59, mean 50 torr). Spontaneous respiratory rate steadily
declined (initially 70-80 br/min, 45-50 br/min at discontinuation).
CXR results demonstrated improvement after 12 hours of NHFV without
any evidence of hyperinflation. While allocation of resources may
prevent NIPPV as primary non-invasive mode, NHFV but should be
considered an option when NCPAP or NSIMV do not maintain adequate
post-extubation support.