Impact of proning with and without inhaled pulmonary vasodilators and neuromuscular blocking agents in COVID acute respiratory distress syndrome

Table 4 Clinical features, ventilator settings and outcomes of treatment sub-group analysis

Characteristic	PPV		PPV + IVd		PPV + NMBA	PPV + NMBA + IVd		P value
Total	36		36		5	12		-
Highest Sequential Organ Failure Assessment score pre-ICU (mean ± SD)	14.0 ± 2.7		15.2 ± 2.4		12.2 ± 2.9	14.2 ± 4.2		0.089
Respiratory parameters < 24 hours prior to the first proning session (mean ± SD)
FiO2	76.6 ± 20.0		85.3 ± 18.5		70.0 ± 7.0	81.2 ± 21.6		0.237
PaO2	82.4 ± 31.3		73.6 ± 21.4		73.6 ± 21.4	73.6 ± 21.4		0.701
PaO2/FiO2	112.0 ± 68.1		101.3 ± 58.5		101.0 ± 9.3	61.6 ± 55.1		0.241
SpO2	94.0 ± 4.6		93.9 ± 4.8		95.6 ± 3.5	93.9 ± 3.4		0.896
Ventilator parameters < 24 hours prior to the first proning session (mean ± SD)
positive end expiratory pressure, cm H2O	10.7 ± 2.2		12.6 ± 8.8		8.7 ± 2.5	12.8 ± 2.2		0.528
Tidal volume (mL)	413.5 ± 65.0		440.5 ± 70.3		428.7 ± 44.0	443.3 ± 64.0		0.570
Plateau pressure (cm H2O)	24.5 ± 6.1		25.9 ± 4.1		26.5 ± 4.9	27.8 ± 5.8		0.643
Driving pressure (cm H2O)	13.2 ± 12.3		14.3 ± 3.9		18.0 ± 0.0	15.8 ± 4.7		0.373
Tidal compliance (mL/cm H2O)	34.8 ± 12.3		35.5 ± 9.0		29.5 ± 10.60	24.0 ± 6.7		0.185
Peak inspiratory pressure	32.7 ± 7.0		33.5 ± 5.8		24.2 ± 9.9	35.1 ± 9.6		0.111
O2 index	16.8 ± 8.3		15.6 ± 5.5		14.2 ± 2.0	20.5 ± 3.1		0.537
Average duration of intervention
First proning session duration (days)	2.3		3.1		1.0	2.0		-
Total duration of IVd (days)	-		2.9		-	3.7		-
Total duration of NMBA (days)	-	-		3.4		2.7	-
Average time from intubation to first prone (hour)	23.2	18.8		23.5		43.4	-
Primary outcomes
Mortality	21 (58.33)		20 (55.56)		2 (40.00)	4 (33.33)		0.439
Total LOS (mean ± SD)	15.2 ± 10.7		15.8 ± 10.8		32.2 ± 34.2	17.4 ± 8.0		0.618
ICU LOS (mean ± SD)	19.5 ± 11.8		20.6 ± 13.1		34.2 ± 20.0	34.2 ± 34.1		0.737

FiO₂: Fractional inspired oxygen; ICU: Intensive care unit; IVd: Inhaled vasodilators; LOS: Length of stay; NMBA: Neuromuscular blocking agents; PaO_2: Arterial oxygen partial pressure; PPV: Prone position ventilation.