Calculation of the normal range of extravascular lung water

comment on our study [1]. We regret that we did not provide the number of patients with normal lung (NL) and the equation for EVLW and lung weight. We are glad to provide these details now. Nine patients had NL and 21 had lungs heavier than NL (HL). We observed a close correlation between EVLW and postmortem lung weight in both groups (NL, r = 0.78, P < 0.05; HL, r = 0.83, P < 0.01). Th e linear regres sion equations were as follows: for NL, EVLW = 0.53 × Lung weight + 5.0; for HL, EVLW = 0.58 × Lung weight – 90.0. Th e original equation for all 30 patients was EVLW = 0.56 × lung weight – 58.0 [1]. Th e correlation coeffi cients between the subjects was high and the equations were statistically signifi cant for both groups. Although Dr Zhang suggested modifying the ‘correlation coeffi cient’, it is impossible and nonsensical in order to calculate EVLW from the equation. An equation consists of a slope and an intercept. Th erefore, we provide the results com paring those parameters. Th ere was no statistically signi fi cant diff erence in the slope (P = 0.50) and the intercept (P = 0.35) for the equations between NL and HL, and in the slope (P = 0.60) and the intercept (P = 0.52) for the equations between NL and all 30 patients. We hope these data answer Dr Zhang’s insightful comments.