Effects of PEEP on regional ventilation-perfusion mismatch in the acute respiratory distress syndrome

Table 2 Effect of positive end expiratory pressure (PEEP) on the distribution of regional Ventilation and Perfusion (cfr. Fig. 4 curves)

\(\dot{V}\) and \(\dot{Q}\) distribution	PEEP 5 cmH₂O n = 15	PEEP 15 cmH₂O n = 15	p value
Non-dependent region
Mean \(\dot{V}\)	1.63 [1.27–2.39]	1.50 [1.16–1.77]	0.040
logSD\(_{{\dot{V}}}\)	0.05 [0.01–0.11]	0.04 [0.01–0.11]	0.991
Mean \(\dot{Q}\)	1.33 [1.08–1.48]	1.00 [0.93–1.26]	0.009
logSD\(_{{\dot{Q}}}\)	0.02 [0.01–0.05]	0.04 [0.01–0.102]	0.138
Middle region
Mean \(\dot{V}\)	1.02 [0.85–1.14]	1.07 [0.91–1.13]	0.527
logSD\(_{{\dot{V}}}\)	0.08 [0.03–0.11]	0.06 [0.02–0.10]	0.157
Mean \(\dot{Q}\)	0.66 [0.52–0.79]	0.76 [0.66–0.87]	0.001
logSD\(_{{\dot{Q}}}\)	0.05 [0.03–0.12]	0.03 [0.02–0.09]	0.021
Dependent region
Mean \(\dot{V}\)	1.25 [0.83–1.94]	1.28 [0.94–2.63]	0.978
logSD\(_{{\dot{V}}}\)	0.12 [0.08–0.19]	0.13 [0.11–0.25]	0.324
Mean \(\dot{Q}\)	0.46 [0.36–0.84]	0.50 [0.33–0.79]	0.131
logSD\(_{{\dot{Q}}}\)	0.11 [0.08–0.15]	0.09 [0.05–0.14]	0.202

Bold identifies significant differences
Mean \(\dot{V}\) and Mean \(\dot{Q}\) represent the mean \({{\dot{V}} \mathord{\left/ {\vphantom {{\dot{V}} {\dot{Q}}}} \right. \kern-\nulldelimiterspace} {\dot{Q}}}\) ratio of the ventilation and perfusion \({{\dot{V}} \mathord{\left/ {\vphantom {{\dot{V}} {\dot{Q}}}} \right. \kern-\nulldelimiterspace} {\dot{Q}}}\) distribution curves. LogSD\(_{{\dot{V}}}\) and logSD_Q refers to the logarithm of their standard derivation, which is a marker of the curves skewness

ISSN: 1364-8535