Extravascular lung water indexed to predicted body weight is a novel predictor of intensive care unit mortality in patients with acute lung injury. Crit Care Med. 2010;38:114-120. [PMID: 19789451 DOI: 10.1097/ccm.0b013e3181b43050]

Global end-diastolic volume, serum osmolarity, and albumin are risk factors for increased extravascular lung water

BACKGROUND

The transpulmonary thermodilution technique allows the determination of cardiac preload (global end-diastolic volume index) and quantification of pulmonary edema (extravascular lung water index [EVLWI]). Pulmonary edema commonly develops in critically ill patients; however, the underlying pathophysiology, that is, hydrostatic (cardiac) or permeability-induced (noncardiac), often remains unclear. In this study, hemodynamic and serum parameters of osmolarity and oncotic pressure were analyzed to identify risk factors for increased EVLWI.

METHODS

A retrospective, single-center analysis in an intensive care unit of a university hospital was performed. No interventions were made for the study. Forty-two critically ill patients were included, and 126 simultaneous hemodynamic measurements and serum determinations were analyzed by logistic regression and Spearman rank correlation coefficient analysis.

RESULTS

Global end-diastolic volume index (P = .001), serum albumin (P = .006), and serum osmolarity (P = .029) were significant factors for increased EVLWI (defined as >10 mL/kg).

CONCLUSION

Hypervolemia, hypoalbuminemia, and high plasma osmolarity are associated with increased EVLWI.

Validation of extravascular lung water measurement by single transpulmonary thermodilution: human autopsy study

Introduction

Gravimetric validation of single-indicator extravascular lung water (EVLW) and normal EVLW values has not been well studied in humans thus far. The aims of this study were (1) to validate the accuracy of EVLW measurement by single transpulmonary thermodilution with postmortem lung weight measurement in humans and (2) to define the statistically normal EVLW values.

Methods

We evaluated the correlation between pre-mortem EVLW value by single transpulmonary thermodilution and post-mortem lung weight from 30 consecutive autopsies completed within 48 hours following the final thermodilution measurement. A linear regression equation for the correlation was calculated. In order to clarify the normal lung weight value by statistical analysis, we conducted a literature search and obtained the normal reference ranges for post-mortem lung weight. These values were substituted into the equation for the correlation between EVLW and lung weight to estimate the normal EVLW values.

Results

EVLW determined using transpulmonary single thermodilution correlated closely with post-mortem lung weight (r = 0.904, P < 0.001). A linear regression equation was calculated: EVLW (mL) = 0.56 × lung weight (g) - 58.0. The normal EVLW values indexed by predicted body weight were approximately 7.4 ± 3.3 mL/kg (7.5 ± 3.3 mL/kg for males and 7.3 ± 3.3 mL/kg for females).

Conclusions

A definite correlation exists between EVLW measured by the single-indicator transpulmonary thermodilution technique and post-mortem lung weight in humans. The normal EVLW value is approximately 7.4 ± 3.3 mL/kg.

Trial registration

UMIN000002780.

Assessing the quantity of pulmonary edema in critically ill children

Measuring extravascular lung water may be useful for predicting outcome in adults with acute lung injury. The present commentary briefly reviews the potential role and limitations of extravascular lung water measurement in critically ill children.