Feature Articles
Have changes in ventilation practice improved outcome in
children with acute lung injury?*
Waleed H. Albuali, MD; Ram N. Singh, MD, FRCPC; Douglas D. Fraser, MD, PhD, FRCPC; Jamie A. Seabrook, MA;
Brian P. Kavanagh, MD, FRCPC; Christopher S. Parshuram, MD, FRACP; Alik Kornecki, MD
T
he reduction in tidal volume
(VT) administered during me-
chanical ventilation (MV) is
the only intervention that has
been shown to affect survival in adults
with acute lung injury (ALI) (1). Al-
though the optimal VT (2– 4), airway pres-
sure (5), and alternative approaches to
ventilatory management in the setting of
ALI (6) are still controversial issues, it is
clear that the use of VT 12 mL·kg
-1
predicted body weight (PBW) increases
mortality in adults suffering from ALI,
compared with VT of 6 mL·kg
-1
PBW (7).
The optimal management for adults
with ALI or acute respiratory distress syn-
drome (ARDS) remains unresolved, and
the situation is even less clear for chil-
dren. Virtually all the laboratory investi-
gations of ventilator-induced lung injury
have focused on adult animal models (8),
and most of clinical studies were carried
out in adult patients (7, 9 –12).
Notwithstanding its lower incidence
in the pediatric population, ALI bears an
associated mortality of 22% to 27% in
affected children (13, 14). Lacking pri-
mary data in children, various authors
have suggested a number of approaches,
all of which have been extrapolated from
the literature on adults. However, three
lines of evidence raise concerns with such
an approach. First, contrary to empirical
impressions of their greater vulnerability,
recent laboratory data suggest that the
neonatal (15) and infant (16) lungs are
less—not more—vulnerable to the effects
of high VT. Second, the single recent clin-
ical study that did examine the influence
of VT on outcome in pediatric ARDS (a
retrospective case series) (13) indicated
that VT may not be an independent pre-
dictor of outcome. Third, it is known that
very low VTs increase the propensity for
development of atelectasis (17) or, as has
been suggested by some, that low VTs
may increase mortality (2, 3). If this were
true, the effects might be greater in in-
fants and children because their lower
functional residual capacity (18), and
their more compliant chest wall (19)
could further increase the predilection to
atelectasis and the potentially associated
poor outcome. Thus, it is important to
verify the appropriateness of applying
adult recommendations for MV in the pe-
diatric setting.
The effect of VT on mortality should
ideally be investigated in a prospective
randomized clinical trial. We conducted a
retrospective study due to ethical con-
straints associated with exposing children
to a strategy of MV that has been found to
be harmful in adults (7). We chose to first
compare the clinical practice of MV be-
tween 1988 and 1992, when protective
strategies of ventilation were less likely to
have been applied, to a more recent pe-
riod (2000 –2004) during which protec-
tive strategies of MV were established in
*See also p. 397.
From the Department of Pediatrics and Pediatric
Critical Care Unit, Children’s Hospital of Western
Ontario, London Health Sciences Center, University of
Western Ontario, London, ON, Canada (WHA, RNS, DDF,
JAS, AK); and the Departments of Pediatrics and Critical
Care, Hospital for Sick Children, University of Toronto,
Toronto, ON, Canada (BPK, CSP).
The authors have not disclosed any potential con-
flicts of interest.
For information regarding this article, E-mail:
alik.kornecki@lhsc.on.ca
Copyright © 2007 by the Society of Critical Care
Medicine and the World Federation of Pediatric Inten-
sive and Critical Care Societies
DOI: 10.1097/01.PCC.0000269390.48450.AF
Objectives: To describe the changes that have occurred in
mechanical ventilation in children with acute lung injury in our
institution over the last 10 –15 yrs and to examine the impact of
these changes, in particular of the delivered tidal volume on
mortality.
Design: Retrospective study.
Setting: University-affiliated children’s hospital.
Patients: The management of mechanical ventilation between
1988 and 1992 (past group, n 79) was compared with the
management between 2000 and 2004 (recent group, n 85).
Interventions: None.
Measurements and Main Results: The past group patients were
ventilated with a significantly higher mean tidal volume (10.2
1.7 vs. 8.1 1.4 mL·kg
1
actual body weight, p < .001), lower
levels of positive end-expiratory pressure (6.1 2.7 vs. 7.1 2.4
cm H
2
O, p .007), and higher mean peak inspiratory pressure
(31.5 7.3 vs. 27.8 4.2 cm H
2
O, p < .001) than the recent
group patients. The recent group had a lower mortality (21% vs.
35%, p .04) and a greater number of ventilator-free days (16.0
9.0 vs. 12.6 9.9 days, p .03) than the past group. A higher
tidal volume was independently associated with increased mor-
tality (odds ratio 1.59; 95% confidence interval 1.20, 2.10, p <
.001) and reduction in ventilation-free days (95% confidence
interval 1.24, 0.77, p < .001).
Conclusions: The changes in the clinical practice of mechan-
ical ventilation in children in our institution reflect those reported
for adults. In our experience, mortality among children with acute
lung injury was reduced by 40%, and tidal volume was indepen-
dently associated with reduced mortality and an increase in
ventilation-free days. (Pediatr Crit Care Med 2007; 8:324 –330)
KEY WORDS: children; tidal volume; mechanical ventilation;
acute lung injury; acute respiratory distress syndrome; mortality
324 Pediatr Crit Care Med 2007 Vol. 8, No. 4