Comparative effects of flow vs. volume-controlled one-lung ventilation on gas exchange and respiratory system mechanics in pigs

Wittenstein, Jakob; Scharffenberg, Martin; Ran, Xi; Keller, Diana; Michler, Pia; Tauer, Sebastian; Theilen, Raphael; Kiss, Thomas; Bluth, Thomas; Koch, Thea; Gama de Abreu, Marcelo; Huhle, Robert

doi:10.1186/s40635-020-00308-0

Intensive Care Medicine Experimental

Table 2 Respiratory parameters

From: Comparative effects of flow vs. volume-controlled one-lung ventilation on gas exchange and respiratory system mechanics in pigs

Parameter	Therapy				ANOVA (P=)
Group	Mode	20′	40′	60′	Seq	Group	Mode	Time	Mixed
V_T (mL/kg)					0.006	0.730	0.049	0.648	0.137
Norm	VCV	5.1 ± 0.2	5.1 ± 0.2	5.1 ± 0.2			0.042	0.978	0.044
	FCV	5.4 ± 0.3	5.6 ± 0.2	5.6 ± 0.2
		P = 0.020	P < 0.001	P < 0.001
Hypo	VCV	5.1 ± 0.3	5.1 ± 0.3	5.0 ± 0.3			0.251	0.621	0.532
Hypo	FCV	5.4 ± 0.2	5.5 ± 0.3	5.5 ± 0.4
MV (L/min)					0.520	0.799	< 0.001	0.904	0.570
Norm	VCV	7.7 ± 0.5	7.7 ± 0.5	7.7 ± 0.5			< 0.001	0.894	0.995
	FCV	6.8 ± 0.2	6.8 ± 0.4	6.8 ± 0.4
		P < 0.001	P < 0.001	P < 0.001
Hypo	VCV	7.8 ± 0.7	7.8 ± 0.8	7.8 ± 0.8			< 0.001	0.778	0.453
	FCV	6.8 ± 1.0	7 ± 0.8	7.0 ± 0.8
		P < 0.001	P = 0.008	P = 0.002
RR (min^-1)					0.897	0.495	< 0.001	0.989	0.403
Norm	VCV	35 ± 0	35 ± 0	35 ± 0			< 0.001	0.983	0.145
	FCV	29 ± 1	28 ± 1	29 ± 1
		P < 0.001	P < 0.001	P < 0.001
Hypo	VCV	35 ± 0	35 ± 0	35 ± 0			< 0.001	0.999	0.990
	FCV	28 ± 2	29 ± 2	28 ± 2
		P < 0.001	P < 0.001	P < 0.001
Pmean (cmH₂O)					0.345	0.666	0.731	0.756	0.098
Norm	VCV	15.1 ± 1.1	14.8 ± 1.0	14.8 ± 1.1
Norm	FCV	15.3 ± 1.3	16 ± 1.4	15.9 ± 1.1
Hypo	VCV	14.6 ± 1.8	14.8 ± 1.8	14.8 ± 1.8
Hypo	FCV	14.9 ± 3.3	14.8 ± 3.2	15.6 ± 3.4
Ppeak (cmH₂O)					0.498	0.467	< 0.001	0.661	0.419
Norm	VCV	33 ± 3.1	32.3 ± 3.4	32.4 ± 3.3			< 0.001	0.590	0.082
	FCV	28 ± 3.4	29.6 ± 3.4	29.8 ± 3.4
		P = 0.009	P = 0.133	P = 0.143
Hypo	VCV	31.3 ± 3.4	31.8 ± 3.3	32.5 ± 4.3			0.027	0.315	0.715
	FCV	27.4 ± 5.8	26.5 ± 5.3	28 ± 4.8
		P = 0.125	P = 0.033	P = 0.065
PEEP (cmH₂O)					0.265	0.141	0.002	0.977	0.634
Norm	VCV	5.1 ± 0.4	5.1 ± 0.4	5.1 ± 0.3			< 0.001	0.941	0.955
	FCV	4.2 ± 0.2	4.3 ± 0.1	4.2 ± 0.2
		P < 0.001	P < 0.001	P < 0.001
Hypo	VCV	4.9 ± 0.4	4.8 ± 0.3	4.9 ± 0.2			0.111	0.994	0.634
Hypo	FCV	3.7 ± 1.3	4 ± 1.2	3.5 ± 1.6
Total PEEP (cmH₂O)					0.386	0.947	< 0.001	0.885	0.420
Norm	VCV	6.2 ± 0.6	6.3 ± 0.7	6.3 ± 0.7			< 0.001	0.671	0.552
	FCV	4.43 ± 0.1	4.4 ± 0.1	4.3 ± 0.1
		P < 0.001	P < 0.001	P < 0.001
Hypo	VCV	6.6 ± 1.0	6.5 ± 0.7	6.5 ± 0.8			< 0.001	0.906	0.560
	FCV	4.2 ± 0.9	4.4 ± 0.9	4.0 ± 1.0
		P < 0.001	P < 0.001	P < 0.001

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, V_T tidal volume, MV minute volume, RR respiratory rate, P_mean mean tracheal pressure, P_peak peak tracheal pressure, PEEP positive end-expiratory pressure, total PEEP PEEP + intrinsic PEEP

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