Table 2.

Ventilator Settings

Variables	Low Vt (Initial 4 Patients)	Intermediate Vt (Initial 4 Patients)	P Value	Intermediate Vt (8 Patients)
Vt, ml/kg PBW	7.0 ± 0.6	7.7 ± 0.8	0.022	7.5 ± 0.6
PaCO2, mm Hg	57.7 ± 5.2	44.1 ± 3.6	0.003	41.8 ± 3.7
PaO2/FiO2 ratio	207 ± 61	241 ± 38	0.402	230 ± 49
RR, beats/min	21.5 ± 2.0	21.0 ± 1.4	0.182	20.1 ± 1.5
Ve, L/min	9.1 ± 1.0	9.8 ± 1.0	0.020	9.3 ± 1.0
Ventilation ratio	2.1 ± 0.3	1.7 ± 0.2	0.018	1.6 ± 0.2
Pplat, cm H2O	23.3 ± 2.2	23.3 ± 3.1	>0.999	23.6 ± 2.7
PEEP, cm H2O	11.0 ± 1.2	10.0 ± 1.4	0.250	9.6 ± 1.2
ΔP, cm H2O	12.3 ± 1.7	13.5 ± 2.7	0.080	14.1 ± 2.5
Cst, ml/cm H2O	35.7 ± 5.8	36.1 ± 7.9	0.595	33.9 ± 7.6
EELV, ml	—	2,559 ± 61	—	2,285 ± 355

Definition of abbreviations: Cst = static respiratory system compliance; ΔP = driving pressure; EELV = end-expiratory lung volume; PBW = predicted body weight; PEEP = positive end-expiratory pressure; Pplat = plateau pressure; RR = respiratory rate.

Data are presented as mean ± SD. P value indicates difference between low Vt and intermediate Vt of the initial four patients using a paired t test.