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 1 Respiratory and hemodynamic parameters

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

	Group	Baseline	+ Lavage	+ RM 1	+ RM 2	+ RM 3	p value
	Group	Baseline	+ Lavage	After Lavage	After 3 h LV_T vs HV_T	After 3 h LV_T	Group effect	Time effect	Group : Time
PIP [cmH₂O]	A	20.8± 1.3	30.0 ± 2.8	31.2 ± 2.3	29.7 ± 4.9	27.2 ± 4.8	0.4881	< 0.001	0.1739
PIP [cmH₂O]	B	20.2 ± 1.3	32.2 ± 5.3	32.0 ± 8.2	35.8 ± 6.9	27.5 ± 2.7	0.4881	< 0.001	0.1739
PEEP [cmH₂O]	A	7.2 ± 1.0	6.2 ± 0.4	15.0 ± 0.0	15.3 ± 0.5	15.3 ± 0.5	0.5759	< 0.001	0.0709
PEEP [cmH₂O]	B	7.3 ± 0.8	6.2 ± 0.4	15.3 ± 0.5	15.7 ± 0.5	15.0 ± 0.0	0.5759	< 0.001	0.0709
△P [cmH₂O]	A	13.7 ± 1.7	24.0 ± 2.8	16.1 ± 2.3	14.7 ± 4.9	12.1 ± 4.8	0.5983	< 0.001	0.2651
△P [cmH₂O]	B	12.8 ± 1.6	26.2 ± 5.3	19.9 ± 8.2	18.4 ± 3.9	12.5 ± 2.7	0.5983	< 0.001	0.2651
C_rs [ml/cmH₂O]	A	27.0 ± 4.5	11.7 ± 1.6	18.3 ± 2.0	22.3 ± 8.8	29.8 ± 11.4	0.6959	< 0.001	0.2601
C_rs [ml/cmH₂O]	B	31.3 ± 5.2	11.0 ± 1.7	18.7 ± 5.1	17.7 ± 4.5	23.8 ± 5.0	0.6959	< 0.001	0.2601
M_P [J/min]	A	20 ± 3	15 ± 3	17 ± 3	16 ± 2	15 ± 3	0.7976	< 0.001	0.4778
M_P [J/min]	B	19 ± 2	17 ± 3	17 ± 3	18 ± 6	14 ± 1	0.7976	< 0.001	0.4778
P_aO₂ [mmHg]	A	535 ± 61	84 ± 13	395 ± 109	369 ± 132	470 ± 68	< 0.001	< 0.001	< 0.001
P_aO₂ [mmHg]	B	536 ± 60	80 ± 15	270 ± 112	167 ± 87	185 ± 129	< 0.001	< 0.001	< 0.001
P_aCO₂ [mmHg]	A	51 ± 5	80 ± 16	80 ± 13	97 ± 21	94 ± 21	0.1715	< 0.001	0.0882
P_aCO₂ [mmHg]	B	47 ± 6	84 ± 8	81 ± 9	103 ± 11	123 ± 10	0.1715	< 0.001	0.0882
mPAP [mmHg]	A	17 ± 3	27 ± 8	23 ± 5	24 ± 6	22 ± 4	0.0417	< 0.001	0.0034
mPAP [mmHg]	B	15 ± 1	28 ± 2	23 ± 2	33 ± 6	30 ± 3	0.0417	< 0.001	0.0034
PVR [dyn∙sec∙cm⁻⁵]	A	179 ± 68	/	257 ± 105	202 ± 77	153 ± 50	0.0256	< 0.001	0.1297
PVR [dyn∙sec∙cm⁻⁵]	B	159 ± 25	/	321 ± 92	369 ± 58	224 ± 113	0.0256	< 0.001	0.1297
CO [L/min]	A	3.6 ± 1.3	/	4.4 ± 2.3	5.7 ± 2.6	6.3 ± 2.4	0.6719	< 0.001	0.1915
CO [L/min]	B	4.2 ± 0.7	/	3.6 ± 1.2	5.3 ± 0.8	6.9 ± 1.0	0.6719	< 0.001	0.1915

Respiratory mechanics, pulmonary function and hemodynamics were assessed in anesthetized pigs at baseline, after lavage-induced surfactant depletion, and after consecutive recruitment maneuvers (RM) at 3-h intervals. Group A, N = 6: continuous automated protective low tidal volume ventilation. Group B, N = 6: 3 h of injurious high tidal volume ventilation (HV_T) before RM 2, resumption of protective low tidal volume ventilation (LV_T) for 3 h before RM 3. Two animals died after injurious HV_T and RM 2, i.e., Group B, N = 4 at RM 3. For experimental protocol, see Fig. 1. Means ± SD; p-values for group effects (inter-group) and/or time effects (intra-group) were calculated using two-way ANOVA-type statistic using the nparLD package. For more statistical details, refer to main text. PIP peak inspiratory pressure, PEEP positive end-expiratory pressure, ΔP driving pressure, C_rs dynamic respiratory system compliance; M_P mechanical power, 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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