Extravascular lung water index improves the diagnostic accuracy of lung injury in patients with shock.
BACKGROUND
The diagnosis of acute lung injury (ALI) may be more robust if more accurate physiological markers can be identified. Extravascular lung water (EVLW) is one possible marker, and it has been shown to correlate with respiratory function and mortality in patients with sepsis. Whether EVLW confers diagnostic value in a general population with shock, as well as which index performs best, is unclear. We investigated the diagnostic accuracy of various EVLW indices in patients with shock.


METHODS
We studied a prospective, observational cohort of 51 patients with shock admitted to a tertiary ICU. EVLW was measured within 6 hours of ICU admission and indexed to actual body weight (EVLW/ABW), predicted body weight (EVLW/PBW) and pulmonary blood volume (EVLW/PBV). The relationship of these indices to the diagnosis and severity of lung injury and ICU mortality were studied. Positive and negative likelihood ratios, pre- and posttest odds for diagnosis of lung injury and mortality were calculated.


RESULTS
All EVLW indices were higher among patients with lung injury and significantly correlated with respiratory parameters. Furthermore, all EVLW indices were significantly higher in nonsurvivors. The use of EVLW improves the posttest OR for the diagnosis of ALI, acute respiratory distress syndrome (ARDS) and severe lung injury (sLI) by up to eightfold. Combining increased EVLW and a diagnosis of ALI, ARDS or sLI increases the posttest odds of ICU mortality. EVLW/ABW and EVLW/PBV demonstrated the best diagnostic performance in this population.


CONCLUSIONS
EVLW was associated with degree of lung injury and mortality, regardless of the index used, confirming that it may be used as a bedside indicator of disease severity. The use of EVLW as a bedside test conferred added diagnostic value for the identification of patients with lung injury.
Department of Intensive Care Medicine, Skåne University Hospital Malmö, Södra Förstadsgatan, Lund University, S-20502 Malmö, Sweden. michelle.chew@med.lu.se
Michelle S
MS
Chew
Lilian
L
Ihrman
Joachim
J
During
Lill
L
Bergenzaun
Anders
A
Ersson
Johan
J
Undén
Jörgen
J
Ryden
Eva
E
Åkerman
Marina
M
Larsson
D000368:Aged; D015331:Cohort Studies; D015633:Extravascular Lung Water / Q000502:physiology*; D005260:Female; D006801:Humans; D055370:Lung Injury / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012769:Shock / Q000175:diagnosis* / Q000453:epidemiology*