Positive end-expiratory pressure limits inspiratory effort through modulation of the effort-to-drive ratio: an experimental crossover study

Intensive Care Medicine Experimental

Table 1 Respiratory measurements

	PEEP 0^I	PEEP 3^I	PEEP 6^I	PEEP 9^I	PEEP 12^I	PEEP 15^I	p-value
Sampled PEEP (cmH₂O)	1.21	3.86	6.62	9.12	11.97	14.93
SD	0.72	0.97	0.67	0.46	0.19	0.24
Breathing rate	84	76	63	47	34	31	< 0.01
SD	19	17	15	12	14	17
Tidal volume (L)	0.120	0.141	0.185	0.209	0.273	0.278	< 0.01
SD	0.059	0.069	0.089	0.090	0.092	0.101
SER	33%	30%	26%	18%	12%	10%	< 0.01
SD	17%	19%	17%	16%	14%	12%
ΔPes_max (cmH₂O)	− 4.2	− 3.9	− 3.4	− 2.3	− 2.3	− 1.9	< 0.01
SD	3.1	2.5	2.1	1.5	2.0	1.5
ΔPL (cmH₂O)	10.2	10.3	11.2	9.7	13.5	12.0	< 0.01
SD	5.2	4.5	4.7	3.3	10.2	7.3
EDR (cmH₂O/µV)	− 1.12	− 0.99	− 0.82	− 0.57	− 0.34	− 0.24	< 0.01
SD	1.05	0.88	0.74	0.56	0.39	0.20
Min Edi (µV)	0.90	0.84	0.61	0.33	0.29	0.26	< 0.01
SD	0.71	0.56	0.43	0.17	0.11	0.13
Max Edi (µV)	5.85	5.98	6.41	6.08	8.94	8.29	0.011
SD	3.37	3.41	3.32	3.18	6.31	5.15
ΔEdi (µV)	4.95	5.14	5.81	5.75	8.64	8.25	< 0.01
SD	2.89	3.06	3.08	3.07	6.29	5.04

Effects of the PEEP level on respiratory measurements. Means and standard deviations (SD) are presented for the incremental PEEP levels (PEEP^I). Friedman test was used for analysis of variance
PEEP positive end-expiratory pressure, SER spontaneous effort ratio, ΔPes_max maximum inspiratory change in esophageal pressure, ΔPL transpulmonary driving pressure, EDR Effort-to-drive ratio, Edi electric activity of the diaphragm, ΔEdi tidal change from lowest to highest Edi