Table 3.

Respiratory mechanics and mechanical power

Parameter	Therapy				ANOVA (P=)
Group	Mode	20′	40′	60′	Seq	Group	Mode	Time	Mixed
R (cmH2O s/L)					0.171	0.531	< 0.001	1.000	0.896
Norm	VCV	32.7 ± 7.59	33.3 ± 7.81	32.8 ± 7.53			< 0.001	0.977	0.963
	FCV	7.26 ± 0.973	8.1 ± 3.29	7.47 ± 1.73
		P < 0.001	P < 0.001	P < 0.001
Hypo	VCV	35 ± 9.18	34.5 ± 11	34.9 ± 11.1			< 0.001	0.986	0.860
	FCV	8.58 ± 8.49	8.08 ± 6.78	7.44 ± 6.26
		P = 0.003	P = 0.004	P = 0.003
C (mL/cmH2O)					0.882	0.142	0.006	0.980	0.860
Norm	VCV	11 ± 1.77	11.7 ± 2.06	11.6 ± 2.19			0.050	0.347	0.849
	FCV	9.34 ± 1.61	9.7 ± 1.23	9.72 ± 1.57
Hypo	VCV	12.9 ± 2.36	12.3 ± 2.13	12.3 ± 2.29			0.037	0.175	0.969
	FCV	11.5 ± 2.13	11 ± 1.8	10.9 ± 1.63
		P = 0.042	P = 0.013	P = 0.041
MPresis (J/min)					0.375	0.521	< 0.001	0.840	0.901
Norm	VCV	6.5 ± 1.3	6.6 ± 1.4	6.4 ± 1.4			< 0.001	0.855	0.787
	FCV	1.2 ± 0.2	1.3 ± 0.4	1.3 ± 0.3
		P < 0.001	P < 0.001	P < 0.001
Hypo	VCV	7.2 ± 2.1	7.0 ± 2.3	7.1 ± 2.3			< 0.001	0.899	0.992
	FCV	1.3 ± 0.9	1.2 ± 0.7	1.2 ± 0.7
		P < 0.001	P = 0.001	P < 0.001
MPelas (J/min)					0.392	0.437	0.243	0.931	0.206
Norm	VCV	7.6 ± 1.2	7.4 ± 1.4	7.4 ± 1.4
	FCV	8.4 ± 1.4	8.7 ± 1.6	8.9 ± 1.7
Hypo	VCV	6.9 ± 1.8	7.1 ± 1.5	7.1 ± 1.5
	FCV	7.5 ± 2.9	8.0 ± 2.4	8.1 ± 2.5

Values in mean ± standard deviation; Statistical P values according to linear mixed-effects repeated-measures ANOVA with within subject factors: mode of ventilation (volume or flow-controlled ventilation) and time of therapy in minutes; and between subject factors group of therapy (normovolaemia or hypovolaemia) and randomisation sequence (volume or flow-controlled ventilation first). Significance was accepted for P < 0.05. Statistical analysis was performed in R statistical programming language and the package lme4.

FCV flow-controlled ventilation, VCV volume-controlled ventilation, C compliance of the respiratory system, MP_resis resistive mechanical power, MP_elas elastic mechanical power