VILI NEJM

Question 1

Def :

Answer 1

Question 2

Pathophysiology -

Physical and biological

Physical ?
Describe high lung volume injury- volutrauma
Low lung volume injury
Atelectrauma

Biological factors ?
Biotrauma

Answer 2

Dreyfuss et al.15 found that pulmonary edema
developed in animals undergoing ventilation with
high tidal volumes, whereas such edema did not
develop in animals undergoing ventilation with
similar airway pressures but with straps around
their abdomens and chests that reduced the tidal
volumes. Thus, their experiments showed that
volume (i.e., lung stretching), not airway pressure,
was the most important factor in determining
injury, a finding that led them to coin the
term “volutrauma.”

Ventilation that occurs at low (absolute) lung volumes
can also cause injury through multiple
mechanisms, including repetitive opening and
closing of airways and lung units,17,18 effects on
surfactant function,19 and regional hypoxia. This
type of injury, which is characterized by epithelial
sloughing, hyaline membranes, and pulmonary
edema, has been termed “atelectrauma.”17
The physical forces described above may cause the
release of various intracellular mediators21 either
directly (by injuring various cells) or indirectly
(by transducing these forces into activation of
cell-signaling pathways in epithelial, endothelial,
or inflammatory cells). Some mediators may directly
injure the lung; others may set the stage for
subsequent development of pulmonary fibrosis.22
Additional mediators may act as homing molecules
recruiting cells (e.g., neutrophils) to the
lung, and such cells can then release more injurious
molecules (Fig. 2).
This process has been termed biotrauma.23
The translocation of mediators,24 bacteria,25 or
lipopolysaccharide26 from the airspaces into the
systemic circulation may occur in lungs that
have increased alveolar–capillary permeability,
which is inherent in the case of ARDS or which
is induced by volutrauma or epithelial microtears.
This translocation may lead to subsequent multiorgan
dysfunction and death27

Question 3

Ventilation strategy for vili ?

Answer 3

Various ventilation strategies have been used to
minimize lung injury: low tidal volumes to limit
overdistention, higher PEEPs to prevent injury
from low lung volume (atelectrauma), and recruitment
maneuvers (i.e., procedures that are used to
reinflate collapsed lung units) that involve sustained
application of an airway pressure of more
than approximately 35 cm of water. The increase
in pressure can inflate atelectatic lung regions
and minimize ventilation heterogeneity. Studies
addressing these interventions are summarized
briefly below.

Question 4

Give adjunctive strategies ?

Answer 4

Prone
NM blocking agents
Anti inflammatory Rx