Results
A total of 100 patients (50 in CTSS group and 50 in
OTSS group) were enrolled. Demographic characteristics of patients, including age, sex, and primary diagnosis were not signifiantly diffrent between two groups
(Table 1). No signifiant diffrence could be observed
regarding the occurrence of sinusitis, type of humidifiation, and stress ulcer prophylaxis between two
groups. APACHE II scores were not signifiantly diffrent between two groups, and had a mean of 24 for the
OTSS group and 25 for the CTSS group, implying homogeneity between the groups with regardto the illness
severity.
Among the patients in OTSS and CTSS groups, 20% and
12% developed VAP, respectively (P > 0.05) (Table 1). Incidence of VAP among all patients enrolled in this study
was 16%. Tracheostomy, sinusitis and type of humidifcation did not show signifiant diffrence between patients with or without VAP. Drainage of subglottic secretion decreased the incidence of VAP (P < 0.05). Also type
of pharmacologic medicine for stress ulcer prophylaxis
has a signifiant effct on VAP incidence (Table 2). The
multivariate analysis implies that patients exposed to
PPI and H2 antagonists had a higher chance of VAP development compared with sucralfate (Table 3). Due to
the low number of outcome and collinearity of its follow-up, subglottic drainage as an independent variable
was removed from the model. Use of CTSS comparing
with OTSS did not show statistically signifiant effct
on VAP incidence in multivariate analysis; however, OR
tended to identify OTSS as an exposure factor for the
development of VAP (OR = 1.92; CI = 0.45-8.30; P = 0.38)
compared with the CTSS. In other words, patients undergoing open suction had a 92% higher chance of developing VAP. Higher level of APACHE II score, sinusitis
and undergoing tracheostomy put the patients at the
risk of VAP. However, using HME instead of humidifir
would decrease this risk. We had one case of exogenous
VAP in each group, with the isolation of the similar
microorganism that had not been previously isolated
from their throats; this might have been due to bronchoscopy procedure in these patients.