Extravascular lung water volume measurement by a novel lithium-thermal indicator dilution method: comparison of three techniques to post-mortem gravimetry

• Published in: Intensive care medicine Vol. 34; no. 11; pp. 2106 - 2111
• Main Authors: Maddison, Benjamin, Giudici, Riccardo, Calzia, Enrico, Wolff, Christopher, Hinds, Charles, Radermacher, Peter, Pearse, Rupert M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.11.2008; Springer; Springer Nature B.V
• Subjects: Analysis of Variance; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Anesthesiology; Animals; Biological and medical sciences; Brief Report; Cardiovascular system; Critical Care Medicine; Disease Models, Animal; Emergency Medicine; Extravascular Lung Water - metabolism; Intensive; Intensive care medicine; Investigative techniques of hemodynamics; Investigative techniques, diagnostic techniques (general aspects); Ischemia - diagnosis; Ischemia - physiopathology; Linear Models; Medical sciences; Medicine; Medicine & Public Health; Pain Medicine; Pediatrics; Pneumology/Respiratory System; Sepsis - diagnosis; Sepsis - physiopathology; Statistics, Nonparametric; Swine; Thermodilution - methods; Viscera - blood supply; Extravascular lung water; Acute lung injury; Cardiovascular monitoring; Lithium indicator dilution; Intrathoracic blood volume; Gravimetry; Lung disease; Intensive care; Gravimetry; Acute lung injury; Respiratory disease; Indicator dilution; Lithium; Lung volume; Extravascular water; Cardiovascular monitoring; Intrathoracic blood volume; Extravascular lung water; Volume measurement; Blood volume; Comparative study; Monitoring; Resuscitation
• ISSN: 0342-4642; 1432-1238
• DOI: 10.1007/s00134-008-1207-4

Objective To compare the lithium-thermal double indicator dilution (Li-thermal), indocyanine green-thermal double indicator dilution (ICG-thermal), single thermal indicator dilution (single-thermal) and gravimetric techniques of extravascular lung water volume (EVLW) measurement in porcine models of acute lung injury. Design Two animal models designed to invoke a systemic inflammatory response. Setting Laboratory study. Subjects A total of 12 immature Deutsches Landschwein pigs. Interventions Extravascular lung water volume was measured at four time points using Li-thermal, ICG-thermal and single-thermal techniques. Measurements were performed using existing technology according to manufacturer’s instructions. Post-mortem gravimetric EVLW measurements were performed by measuring wet and dry mass of lung tissue. Measurements were compared using the Bland–Altman method. Data are presented as mean (SD). Measurements and main results Data were collected in 12 animals and comparison between all 4 techniques was possible in 10 animals. EVLW measured by gravimetry was 9.2 (±3.0)ml kg −1 . When compared to gravimetry, both Li-thermal and ICG-thermal techniques showed minimal bias but wide limits of agreement (LOA) [Li-thermal: bias −1.8 ml kg −1 (LOA ± 13.1); ICG-thermal bias −1.0 ml kg −1 (LOA ± 6.6)]. Comparison between the single-thermal and gravimetric methods identified both considerable bias and wide LOA [+8.5 ml kg −1 (LOA ± 14.5)]. Conclusion Clinically significant differences between EVLW measurements obtained with the gravimetric method and three in vivo indicator dilution techniques were identified. While none of the techniques could be considered ideal, the ICG-thermal method appeared more reliable than either the Li-thermal or single thermal techniques. Further research is required to determine whether the accuracy of the prototype Li-thermal technique can be improved.