Positive end-expiratory airway pressure does not aggravate ventilator-induced diaphragmatic dysfunction in rabbits

Table 5 Diaphragm muscle contractile proteins with various modes mechanical ventilation, with and without applied positive end-expiratory airway pressure ^a

	Control	CPAP	CPAP-8	AMV	AMV-8	CMV	CMV-8
Myosin and actin (% of total protein pool)
Myosin	41.2 ± 1.0	44.5 ± 1.6	41.3 ± 1.6	41.1 ± 1.4	37.5 ± 0.9^b	38.5 ± 1.3^b	41.6 ± 1.5
Actin	20.2 ± 1.0	18.1 ± 1.3	19.1 ± 1.0	18.9 ± 1.6	21.7 ± 2.0	18.0 ± 1.5	17.3 ± 1.4
Myosin heavy-chain isoform expression (%)
MyHC_slow	35.3 ± 3.3	34.4 ± 1.3	29.9 ± 2.3	33.7 ± 1.6	30.5 ± 2.1	35.3 ± 2.0	29.5 ± 1.9
MyHC_2A	54.4 ± 2.8	53.9 ± 1.8	60.3 ± 3.0	54.7 ± 1.4	59.0 ± 2.8	50.9 ± 2.3	55.6 ± 2.2
MyHC_2X	10.3 ± 0.6	11.7 ± 0.6	9.8 ± 1.1	11.6 ± 0.9	10.4 ± 1.2	13.8 ± 0.4	14.9 ± 0.9^b

^aValues are mean ± SE (n = 6 animals in each group). AMV, Assist-control mechanical ventilation; CMV, Controlled mechanical ventilation (numerical value of 8 next to ventilatory mode denotes the set CPAP or PEEP of 8 cmH₂O); CPAP, Continuous positive airway pressure; MyHC, Myosin heavy chain; PEEP, Positive end-expiratory pressure. ^bFor myosin, P < 0.05 compared with CPAP; ^bfor MyHC_2X isoform, P < 0.05 compared with control, CPAP-8 and AMV-8.

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