2004 OPEN FORUM Abstracts
WEANING THE VENTILATOR DEPENDENT PATIENT WITH WEST NILE VIRUS
Wendy
Woods Dedrick, RRT, Melanie Ziolkowski, BSN, RRT, Susan Sampson,
CRTT Eric
S. Yaeger, MD Kindred
Hospital Denver, Denver, Colorado
Background:
The West Nile Virus (WNV) made a significant impact in the United
States for the first time in 1999. According to the CDC, Colorado had
the highest reported WNV activity in the year 2003 with a total of
2947 cases. The full clinical spectrum of WNV is highly variable.
Approximately one in 150 cases of WNV infection results in severe
neurologic disease including meningitis, encephalitis, or
meningoencephalitis that may lead to permanent neurological damage of
varying degrees and/or death. Kindred Hospital Denver (KHD), a Long
Term Acute Care (LTAC) hospital, admitted a total of 15 WNV patients
(PT) during the year 2003. Fourteen out of the 15 PT were admitted
with a diagnosis of respiratory failure (RF), ventilator dependency,
and paralysis. This study was conducted to determine if the different
types of clinical manifestations of WNV infection (encephalitis with
or without flaccid paralysis and meningoencephalitis with or without
flaccid paralysis) influenced weaning success from mechanical
ventilation (MV) based on objective measures of respiratory muscle
strength using rapid shallow breathing index (RSBI) and negative
inspiratory force (NIF).
Method:
Retrospective chart review was conducted of PT admitted to KHD in
2003 with a diagnosis of WNV. All PT had documented positive
serological evidence of WNV infection. Data collected was PT history
and physical, age, date of documented positive serological evidence
of WNV, degree of paralysis, average RSBI and NIF upon admission and
average RSBI and NIF before successful liberation from MV or
discharge, weaning techniques, average number of days to SBT, and
average number of days to liberation from MV.
Results:
A total of 15 PT, mean age 65 (range 27-84), were admitted to KHD
with documented serological evidence of WNV. Fourteen of the PT were
admitted with RF, ventilator dependency, and paralysis. One patient
was admitted on room air for rehabilitation. The clinical
manifestations in the representative sample are as follows: 3 PT
diagnosed with meningoencephalitis with flaccid paralysis, 1 patient
with meningoencephalitis without flaccid paralysis, 5 PT diagnosed
with encephalitis with flaccid paralysis and 5 PT diagnosed with
encephalitis without flaccid paralysis. Eight of the 14 PT were
successfully liberated from MV. Admission respiratory muscle strength
demonstrated an average RSBI 104 and NIF –22 in successfully
weaned PT. Further, respiratory muscle strength improved before
successful liberation from MV with an average RSBI 89 and NIF –28.
Upon admission, non-weanable PT exhibited an average RSBI 219 and NIF
–12 and upon discharge average RSBI 260 NIF –14.
Modalities for successfully weaning this difficult patient population
included the utilization of Transtracheal Augmented Ventilation
(TTAV) during SBT for 6 PT. Two PT utilized the trach collar for SBT
weans. Average number of days to SBT was 14, and average number of
days to liberate the 8 PT from MV was 30. One hundred percent of PT
diagnosed with encephalitis or meningoencephalitis without
flaccid paralysis and 40% of PT diagnosed with encephalitis with
flaccid paralysis were successfully liberated from MV. None of the PT
diagnosed with meningeoencephalitis with flaccid paralysis
were successfully weaned.
Conclusion:
Long-term outcome of PT with WNV is variable. KHD overall weaning
success rate for PT admitted with WNV, RF, and paralysis was 57%. The
different clinical manifestations of WNV influenced the wean success
rate. No PT diagnosed with meningoencephalitis and flaccid paralysis
was able to wean successfully from MV. However, even PT with poor
respiratory mechanics could be weaned utilizing a multidisciplinary
approach. Further studies are needed to corroborate the results due
to the small number of PT in this descriptive analysis.