Physiological predictors of survival during high-frequency oscillatory ventilation inadults with acute respiratory distress syndrome

Table 3 Patient characteristics at 30 days: comparison of survivors versusnon-survivors

Variable	Survivors (number = 45)		Non-survivors (number = 57)
	Mean	SD	Mean	SD	P value
Demographics
Age, years	45.7	16.2	54.9	14.6	0.003
Weight, Kg	75.8	22.7	75.6	20.2	ns
APACHE II (prior to HFOV)	22.9	6.52	24.98	8.96	ns
Murray Score	3.0	0.62	2.9	0.77	ns
Duration ARDS prior to HFOV, days	2.9	3.6	4.5	4.7	0.015
Duration CMV prior to HFOV, hours	88.9	131.9	90.4	105.9	ns
Gas exchange indices
PaO₂/ FiO₂ prior to HFOV, mmHg	96.8	38.8	90.8	38.3	ns
PaO₂/ FiO₂ return to CMV, mmHg	211.5	96.0	129.0	70.5	0.001
Δ PaO₂ / FiO₂	111.0	89.3	26.7	63.0	<0.01
PaCO₂ prior to HFOV, mmHg	54.0	20.8	60.8	17.0	ns
PaCO₂ return to CMV, mmHg	50.3	17.3	81.8	97.4	0.049
OI prior HFOV, cmH₂O· mmHg^-1	26.1	13.4	27.6	13.4	ns
OI return to CMV, cmH₂O· mmHg^-1	10.1	6.6	21.8	19.1	0.01
Max PaCO₂, mmHg	55.5	10.6	66.7	18.8	<0.01
Min PaCO₂, mmHg	36.0	6.7	47.9	16.0	<0.01
pH prior to HFOV	7.3	0.14	7.23	0.12	<0.01
pH return to CMV	7.4	0.1	7.27	0.1	<0.01
Hemodynamic indices
MAP prior to HFOV, mmHg	76.3	15.4	75.1	12.9	ns
MAP return to CMV, mmHg	82.9	14.6	77.0	20.9	ns
CO prior to HFOV, L · min^-1	6.1	2.0	5.8	1.5	ns
CO return to CMV, L ·min^-1	5.9	1.3	6.1	0.5	ns
Ventilator Indices					ns
Vt prior to HFOV, mL ·Kg^-1	7.4	2.4	6.9	2.2	ns
Vt return to CMV, mL ·Kg^-1	6.9	2.1	6.8	1.9	ns
PIP prior to HFOV, cmH₂O	31.8	6.2	32.3	5.2	ns
PIP return to CMV, cmH₂O	28.5	5.2	30.3	5.98	ns
PEEP prior to HFOV, cmH₂O	12.9	4.0	12.1	3.4	ns
PEEP return to CMV, cmH₂O	10.5	2.7	10.8	3.3	ns
CDP prior to HFOV, cmH₂O	21.8	5.7	21.4	4.3	ns
CDP return to CMV, cmH₂O	17.5	4.5	20.7	5.9	0.02
Δ CDP, cmH₂O	-3.9	6.5	-0.57	4.6	0.03

CDP, continuous distending pressure; CMV, conventional mechanical ventilation;CO, cardiac output; FiO₂, fraction of inspired oxygen; HFOV,high-frequency oscillatory ventilation; OI,Oxygenation Index (OI =(FiO₂•CDP•100)/PaO₂); PAWP, pulmonaryartery wedge pressure; PEEP, positive end-expiratory pressure; PIP, peakinspiratory pressure; Vt, tidal volume; = change post-HFOV to pre-HFOV.

ISSN: 1364-8535