Induction of severe hypoxemia and low lung recruitability for the evaluation of therapeutic ventilation strategies: a translational model of combined surfactant-depletion and ventilator-induced lung injury

Boerger, Emilia; Russ, Martin; von Platen, Philip; Taher, Mahdi; Hinken, Lea; Pomprapa, Anake; Koebrich, Rainer; Konietschke, Frank; Graw, Jan Adriaan; Lachmann, Burkhard; Braun, Wolfgang; Leonhardt, Steffen; Pickerodt, Philipp A.; Francis, Roland C. E.

doi:10.1186/s40635-022-00456-5

Intensive Care Medicine Experimental

Table 2 Respiratory and hemodynamic parameters during low and high tidal volume ventilation

From: Induction of severe hypoxemia and low lung recruitability for the evaluation of therapeutic ventilation strategies: a translational model of combined surfactant-depletion and ventilator-induced lung injury

		Ventilation Phase 1—Group A: LV_T, Group B: HV_T						Ventilation Phase 2—Group A & B: LV_T
	Group	1 h	2 h	3 h	p value			1 h	2 h	3 h	p value
		1 h	2 h	3 h	Group effect	Time effect	Group : Time	1 h	2 h	3 h	Group effect	Time effect	Group : Time
PIP [cmH₂O]	A	29.8 ± 3.4	28.8 ± 4.2	28.2 ± 4.8	< 0.001	0.8864	0.3043	25.7 ± 2.4	26.2 ± 2.9	26.2 ± 3.5	< 0.001	0.5382	0.1304
PIP [cmH₂O]	B	48.8 ± 7.5	50.2 ± 8.8	51.3 ± 8.6	< 0.001	0.8864	0.3043	38.5 ± 4.1	37.3 ± 8.1	35.3 ± 4.4	< 0.001	0.5382	0.1304
PEEP [cmH₂O]	A	12.2 ± 5.1	11.2 ± 5.1	10.8 ± 3.1	< 0.001	0.6574	0.6574	11.0 ± 3.8	11.7 ± 4.3	11.0 ± 4.6	< 0.001	0.4036	0.1401
PEEP [cmH₂O]	B	2.3 ± 0.5	2.3 ± 0.5	2.3 ± 0.5	< 0.001	0.6574	0.6574	20.0 ± 3.7	17.8 ± 3.5	16.5 ± 2.5	< 0.001	0.4036	0.1401
△P [cmH₂O]	A	17.7 ± 3.8	17.7 ± 4.1	17.3 ± 3.2	< 0.001	0.7429	0.3450	14.7 ± 4.1	14.5 ± 3.9	15.2 ± 3.6	0.0283	0.7331	0.9275
△P [cmH₂O]	B	46.5 ± 7.0	47.8 ± 8.4	49.0 ± 8.2	< 0.001	0.7429	0.3450	18.5 ± 1.0	19.5 ± 5.1	18.8 ± 2.6	0.0283	0.7331	0.9275
V_T [ml/kg BW]	A	5.9 ± 1.0	6.0 ± 1.1	6.7 ± 0.8	< 0.001	0.3351	0.3351	6.1 ± 0.7	6.0 ± 0.7	6.2 ± 0.4	0.1908	0.9432	0.8194
V_T [ml/kg BW]	B	17.0 ± 0.1	17.0 ± 0.1	17.0 ± 0.1	< 0.001	0.3351	0.3351	6.9 ± 1.4	6.7 ± 0.5	6.7 ± 0.6	0.1908	0.9432	0.8194
RR [x/min]	A	33 ± 4	33 ± 3	33 ± 3	< 0.001	0.3173	0.3173	30 ± 6	33 ± 3	34 ± 2	0.0540	0.1098	0.1098
RR [x/min]	B	12 ± 0	12 ± 0	12 ± 0	< 0.001	0.3173	0.3173	35 ± 0	35 ± 0	35 ± 0	0.0540	0.1098	0.1098
M_P [J/min]	A	25 ± 1	25 ± 5	28 ± 11	< 0.001	0.0792	0.4419	21 ± 7	23 ± 5	25 ± 6	< 0.001	0.8837	0.1737
M_P [J/min]	B	46 ± 10	46 ± 9	47 ± 10	< 0.001	0.0792	0.4419	40 ± 5	38 ± 9	35 ± 3	< 0.001	0.8837	0.1737
C_rs [ml/cmH₂O]	A	17.8 ± 2.3	18.8 ± 4.4	20.8 ± 7.1	0.5463	0.7863	0.0423	23.5 ± 8.2	23.2 ± 7.3	23.7 ± 7.1	0.7851	0.4536	0.6960
C_rs [ml/cmH₂O]	B	20.2 ± 1.8	18.7 ± 3.7	18.8 ± 3.3	0.5463	0.7863	0.0423	20.3 ± 5.1	21.5 ± 4.7	21.5 ± 4.2	0.7851	0.4536	0.6960
P_aO₂ [mmHg]	A	117 ± 33	104 ± 29	104 ± 26	0.0567	< 0.001	0.0650	112 ± 20	111 ± 13	120 ± 15	0.1572	0.5621	0.0863
P_aO₂ [mmHg]	B	246 ± 115	169 ± 108	154 ± 123	0.0567	< 0.001	0.0650	175 ± 67	172 ± 57	128 ± 37	0.1572	0.5621	0.0863
P_aCO₂ [mmHg]	A	87 ± 44	90 ± 51	72 ± 11	0.5409	0.4111	0.2052	85 ± 22	85 ± 20	84 ± 24	0.3105	0.9483	0.5646
P_aCO₂ [mmHg]	B	66 ± 8	70 ± 14	79 ± 23	0.5409	0.4111	0.2052	98 ± 17	90 ± 23	92 ± 5	0.3105	0.9483	0.5646
mPAP [mmHg]	A	28 ± 4	28 ± 4	26 ± 7	0.5904	0.2583	0.0028	25 ± 5	25 ± 7	23 ± 5	0.2209	0.4519	0.2483
mPAP [mmHg]	B	26 ± 3	27 ± 3	33 ± 8	0.5904	0.2583	0.0028	28 ± 2	27 ± 2	28 ± 4	0.2209	0.4519	0.2483
PVR [dyn∙sec∙cm⁻⁵]	A	369 ± 98	347 ± 111	318 ± 145	0.0104	0.9552	0.2871	241 ± 82	218 ± 103	190 ± 92	0.0346	0.1473	0.9471
PVR [dyn∙sec∙cm⁻⁵]	B	452 ± 143	479 ± 166	531 ± 132	0.0104	0.9552	0.2871	352 ± 51	324 ± 107	285 ± 146	0.0346	0.1473	0.9471
CO [L/min]	A	4.5 ± 1.4	4.9 ± 1.4	5.4 ± 2.3	0.0621	0.1528	0.4519	6.0 ± 2.1	6.6 ± 1.2	6.8 ± 1.9	0.0843	0.3471	0.5706
CO [L/min]	B	3.2 ± 1.1	3.4 ± 0.7	3.9 ± 0.9	0.0621	0.1528	0.4519	4.7 ± 2.0	5.0 ± 1.4	5.1 ± 0.8	0.0843	0.3471	0.5706

Respiratory and hemodynamic parameters were assessed in anesthetized and surfactant-depleted pigs which underwent either an automated closed-loop protective low tidal volume (6 ml/kg BW LV_T) and tabular PEEP ventilation strategy (group A) or non-automated injurious high tidal volume ventilation (HV_T) with high V_T of 17 ml/kg BW and PEEP 2 cmH₂O (group B) during ventilation phase 1. Ventilation phase 2 consisted of automated LV_T ventilation in both groups (N = 6 each). Two animals died after injurious HV_T and RM 2, i.e., Group B, N = 4 during ventilation phase 2. For experimental protocol, see Fig. 1 and “Methods” Section. Means ± SD; p-values for group effects (inter-group) and/or time effects (intra-group) were calculated using two-way ANOVA-type statistic using nparLD package. For more statistical details refer to main text. PIP: peak inspiratory pressure, PEEP positive end-expiratory pressure, ΔP driving pressure, V_T tidal volume, RR respiratory rate, M_P mechanical power, C_rs dynamic respiratory system compliance, P_aO₂ arterial partial pressure of oxygen, P_aCO₂ arterial partial pressure of carbon dioxide, mPAP mean pulmonary artery pressure, PVR pulmonary vascular resistance, CO cardiac output

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