Measurement of end-expiratory lung volume by oxygen washin-washout in controlled and assisted mechanically ventilated patients.
OBJECTIVE
Assessing limits of agreement with helium dilution and repeatability of a new system (lung funcution, LUFU) that measures end-expiratory lung volume (EELV) in mechanically ventilated patients using the O(2) washin (EELV(Win)) and washout (EELV(Wout)) technique. LUFU consists of an Evita 4 ventilator, a side-stream oxygen analyzer, and a dedicated PC software.


METHODS
Prospective human study in a general ICU of a University hospital.


METHODS
Thirty-six mechanically ventilated patients.


METHODS
We obtained 36 couples of both EELV(Win) and EELV(Wout) measurements in each patient (5 with healthy lungs, 9 with ALI, 22 with ARDS). Measurements were obtained with patients ventilated either by assisted (ASB, 16 measurements) or controlled (CMV, 20 measurements) ventilation. In 19 of 20 cases in CMV, we obtained helium dilution measurements (EELV(He)).


RESULTS
Bias for agreement with EELV(He) was -16 +/- 156 and 8 +/- 161 ml, respectively, for EELV(Win) and EELV(Wout). Bias for agreement between EELV(Win) and EELV(Wout) was 28 +/- 78 and 23 +/- 168 ml, respectively, for CMV and ASB. During CMV bias for repeatability were 8 +/- 92 and 23 +/- 165 ml, respectively, for EELV(Win) and EELV(Wout). During ASB bias for repeatability were 32 +/- 160 and -15 +/- 147 ml, respectively, for EELV(Win) and EELV(Wout).


CONCLUSIONS
The LUFU method showed good agreement with helium, and good repeatability during partial and controlled mechanical ventilation. The technique is simple and safe.
Patroniti
N
N
Department of Experimental Medicine, University of Milano-Bicocca, Ospedale San Gerardo Nuovo dei Tintori, via Donizetti 106, 20052 Monza, Milan, Italy. nicolo.patroniti@unimib.it
Saini
M
M
Zanella
A
A
Weismann
D
D
Isgrò
S
S
Bellani
G
G
Foti
G
G
Pesenti
A
A
D055371:Acute Lung Injury / Q000628:therapy; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005105:Expiratory Reserve Volume; D005652:Functional Residual Capacity; D006801:Humans; D007362:Intensive Care Units; D008176:Lung Volume Measurements / Q000379:methods*; D008875:Middle Aged; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000628:therapy