Extravascular lung water after pneumonectomy and one-lung ventilation in sheep.
OBJECTIVE
To compare the single thermodilution and the thermal-dye dilution techniques with postmortem gravimetry for assessment of changes in extravascular lung water after pneumonectomy and to explore the evolution of edema after injurious ventilation of the left lung.


METHODS
Experimental study.


METHODS
University laboratory.


METHODS
A total of 30 sheep weighing 35.6 +/- 4.6 kg. The study included two parts: a pneumonectomy study (n = 18) and an injurious ventilation study (n = 12).


METHODS
Sheep were anesthetized and mechanically ventilated with an FiO2 of 0.5, tidal volume of 6 mL/kg, and positive end-expiratory pressure of 2 cm H2O. In the pneumonectomy study, sheep were assigned to right-sided pneumonectomy (n = 7), left-sided pneumonectomy (n = 7), or lateral thoracotomy only (sham operation, n = 4). In the injurious ventilation study, right-sided pneumonectomy was followed by ventilation with a tidal volume of 12 mL/kg and positive end-expiratory pressure of 0 cm H2O (n = 6) or by ventilation with a tidal volume of 6 mL/kg and positive end-expiratory pressure of 2 cm H2O for 4 hrs (n = 6). Volumetric variables, including extravascular lung water index (EVLWI), were measured with single thermodilution (STD; EVLWI(STD)) and thermal-dye dilution (TDD; EVLWI(TDD)) techniques. We monitored pulmonary hemodynamics and respiratory variables. After the sheep were killed, EVLWI was determined for each lung by gravimetry (EVLWI(G)).


RESULTS
In total, the study yielded strong correlations of EVLWI(STD) and EVLWI(TDD) with EVLWI(G) (n = 30; r = .83 and .94, respectively; p < .0001). After pneumonectomy, both the left- and the right-sided pneumonectomy groups displayed significant decreases in EVLWI(STD) and EVLWI(TDD). The injuriously ventilated sheep demonstrated significant increases in EVLWI that were detected by both techniques. The mean biases (+/-2 SD) compared with EVLWI(G) were 3.0 +/- 2.6 mL/kg for EVLWI(STD) and 0.4 +/- 1.6 mL/kg for EVLWI(TDD).


CONCLUSIONS
After pneumonectomy and injurious ventilation of the left lung, TDD and STD displayed changes in extravascular lung water with acceptable accuracy when compared with postmortem gravimetry. Ventilator-induced lung injury seems to be a crucial mechanism of pulmonary edema after pneumonectomy.
Kuzkov
Vsevolod V
VV
Department of Anesthesiology, Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway. v_kuzkov@mail.ru
Suborov
Evgeny V
EV
Kirov
Mikhail Y
MY
Kuklin
Vladimir N
VN
Sobhkhez
Mehrdad
M
Johnsen
Solveig
S
Waerhaug
Kristine
K
Bjertnaes
Lars J
LJ
D000818:Animals; D001784:Blood Gas Analysis; D004195:Disease Models, Animal; D004395:Dye Dilution Technique; D015633:Extravascular Lung Water; D011013:Pneumonectomy / Q000009:adverse effects*; D011654:Pulmonary Edema / Q000209:etiology / Q000503:physiopathology*; D012121:Respiration, Artificial / Q000009:adverse effects*; D012129:Respiratory Function Tests; D012756:Sheep; D013815:Thermodilution / Q000379:methods