Results:
A total of 173 infants with AVB were enrolled with median age of 3 (2-7)
months with male preponderance (65.9%, n=114). The number of cases
admitted during each month are shown in Figure 1. Majority (75.7%,
n=131) were born by vaginal delivery, 13.3% (n=23) were preterm, 28.9%
(n=50) were low birth weight, and median birth weight was 2.6 (2.3-3)
kgs. The median duration of illness was 4 (3-7) days and common clinical
features were rapid breathing (98.8%), cough (98.3%), and fever
(74%). One-third cases (n=59) had one or another underlying
comorbidity. Before referral, 56.1% (n=97) cases were admitted at local
hospitals for 24 (24-72) hours where they received oxygen support
(51.4%) and antibiotics (50.3%).
The examination findings at
admission were tachypnea (98.8%), chest retractions (93.6%),
respiratory failure (84.4%), wheezing (49.7%), crepitations (23.1%),
and oxygen saturation on room air was 88% (82-91%). The chest
radiographs were performed in 65.3% (n=113) cases and common
abnormalities included hyperinflation (75.2%), micro-atelectasis
(54.9%), and para-hilar infiltrates (13.3%) (Table 1).
All infants underwent virological testing for RSV, rhinovirus, influenza
A, PIV 2, PIV 3, and hMPV and 75% (n=128) tested positive for one or
more viruses with total of 166 virus RNA positivity. The most common
viruses identified were RSV (51.2%, n=85), rhinovirus (39.7%, n=66),
influenza A virus (5.4%, n=9), and PIV 3 (3%, n=5), and hMPV (0.6%,
n=1). PIV 2 was not isolated in any case. One-fifth of infants (20.8%,
n=36) had >1 virus isolated (co-infection) and common
combinations were RSV with rhinovirus (14.5%, n=25), and RSV with
influenza A virus (2.3%, n=4) (Table 2).
One-fourth cases developed one or
more complications in form of encephalopathy (17.3%), transaminitis
(14.3%), shock (13.9%), AKI (7.5%), myocarditis (6.4%), MODS
(5.8%), and ARDS (4.6%). All cases were managed with oxygen support.
The highest level of oxygen
support received was in form of nasal cannula (11%), nasal continuous
positive pressure (CPAP) (51.4%), high flow nasal canula (HFNC)
(14.5%), and mechanical ventilation (23.1%). Other treatment included
nebulization (74%, n=128) [3% saline (66.5%), adrenaline (15%),
and salbutamol (13.9%)], intravenous fluids (55.5%, n=96),
intravenous antibiotics (35.9%, n=96), steroids (11.6%, n=20),
vasoactive drugs (13.9%, n=24), and IVIG (1.7%, n=3).
The PICU admission was needed in
36.4% (n=63) cases for 3 (2-6) days. The duration of hospital stay was
5 (3-9) days and the mortality was 8.1% (n=14) (Table 3).
On univariate analysis, infants who required PICU admission had higher
rates of comorbidity (55.6% vs. 21.8%, p=0.001), pre-referral
admission (68.3% vs. 48.2%, p=0.01), fever (84.1% vs. 74%, p=0.02),
chest retractions (100% vs. 90%, p=0.009), respiratory failure at
admission (92.1% vs. 80%, p=0.026), encephalopathy (25.4% vs. 12.7%,
p=0.03), transaminitis (22.2% vs. 10%, n=0.02), shock (20.6% vs. 1%,
p=0.04), MODS (11.1% vs. 2.7%, p=0.029); requirement of mechanical
ventilation (39.6% vs. 13.6%, p<0.001), intravenous fluids
(71.4% vs. 46.4%, p=0.001), and vasoactive drugs (20.6% vs. 1%,
p=0.04); and lower SpO2 at admission [85% (80-90%) vs. 88%
(84-93%), p=0.04] compared to those who did not required PICU
admission (Table 4). The duration of hospital stay was longer in those
who required PICU admission (9 vs. 3 days, p=0.001). On multivariate
analysis, underlying comorbidity (p<0.001); presence of chest
retractions (p<0.001), respiratory failure (p=0.03), lower
oxygen saturation on room air at admission (p=0.01); presence of shock
(p=0.02); and need of mechanical ventilation (p=0.04) were independent
predictors of PICU admission.
There was no difference in demographic details, clinical features,
complications, treatment details, intensive care needs, and outcome
among infants who had atleast one virus detected compared to those with
no virus; and in whom >1 virus detected (co-infection)
compared to those in whom no virus or atleast 1 virus detected (data not
shown).