Critical Care Research and Practice

Research Article

Noninvasive Mechanical Ventilation with Average Volume-Assured Pressure Support versus BiPAP S/T in De Novo Hypoxemic Respiratory Failure

Table 1

Baseline characteristics of the study population.


Patient characteristics (n = 58)
Variables	Mean

Age (years), mean (SD)	68.3 ± 19.3
Sex, N (%)	39 (67) men and 19 (32.8) women
Weight, kg (PBW), mean (SD)	65.5 ± 10
APACHE II score, mean (SD)	18.7 ± 3.0
Risk factors for ARDS
Community pneumonia, N (%)	(87.9) (%)
Postoperative acute abdomen, N (%)	(1.7) (%)
Acute pancreatitis, N (%)	(10.3) (%)
Clinical and radiographic parameters
SBP, mmHg, mean (SD)	123.7 ± 19.1
DBP, mmHg, mean (SD)	74.7 ± 8.8
HR, beat/min, mean (SD)	97.7 ± 13.6
RR, breath/min, mean (SD)	26.6 ± 6.6
Radiographic quadrants affected, number, mean (SD)	1.5 ± 0.6
Gasometric parameters
PAFI (BASAL), mean (SD)	183.5 ± 31.5
pH, mean (SD)	7.43 ± 0.06
pCO₂, mmHg, mean (SD)	32.5 ± 5.8
PO₂, mmHg, mean (SD)	75.3 ± 9.6
HCO₃, mmol/L, mean (SD)	22.5 ± 4.1
EB, mmol/L, mean (SD)	-1.8 ± 6.5
SAT 02 (%), mean (SD)	93 ± 3.1
FiO₂. (%), mean (SD)	41.6 ± 4.2
Ventilatory parameters
VT-AVAPS PROGRAMMED, mean (SD)	489.6 ± 54.3
VT, mL/Kg (PBW), mean (SD)	7.0 ± 1
IPAP maximum programmed (AVAPS), cmH₂O, mean (SD)	15.7 ± 3.2
IPAP patients, cmH₂O, mean (SD)	14.5 ± 2.8
EPAP, cmH₂O, mean (SD)	6 ± 0.4
Leakage, cmH₂O, mean (SD)	17.1 ± 8.9
Vtexh, mL, mean (SD)	473.2 ± 196.1
Vmin, L/min, mean (SD)	13.2 ± 2.5
Final events
Days of hospital stay, mean (SD)	11.8 ± 6.3
Days of stay in ICU, mean (SD)	7.9 ± 4.9
Days of NIMV, mean (SD)	4.3 ± 1.7
Intubated, N (%)	20 (34.5)
Successes of NIMV, N (%)	38 (65.5)
Dead, N (%)	13 (22.4)

APACHE II, assessment score of acute physiology and chronic health evaluation; SBP: systolic blood pressure; DBP: diastolic blood pressure; HR: heart rate; RR: respiratory rate; PAFI: ratio of partial arterial oxygen pressure and inspired fraction of oxygen; PCO₂: partial pressure of carbon dioxide; HCO₃: bicarbonates; EB: excess base; SAT 02: arterial oxygen saturation; FiO₂: inspired fraction of oxygen; VT-AVAPS: tidal volume average volume-assured pressure support; IPAP: inspiratory positive airway pressure; EPAP: expiratory positive airway pressure; Vmin: volume per minute; Vtexh: exhaled tidal volume; Vt: tidal volume.