Table 2.
Patients characteristics stratified by type of respiratory support at the beginning of bronchoscopy for BAL
| Standard oxygen therapy N = 56a |
Nasal high-flow oxygen therapy or non-invasive ventilation N = 49b |
Invasive mechanical ventilation N = 378 |
p valuec | |
|---|---|---|---|---|
| Male sexd | 31 (55.4) | 32 (65.3) | 258 (68.3) | 0.16 |
| Age (years)e | 64 (53–69) | 68 (56–73) | 63 (53–72) | 0.47 |
| SAPSII | 34 (28–45) | 40 (32–45) | 51 (40–63) | < 0.01 |
| Acute respiratory failure | 45 (80.4) | 49 (100) | 359 (95) | < 0.01 |
| Acute respiratory failure for less than 5 days | 30 (53.6) | 29 (59.2) |
198 (52.4) Missing values: n = 1 |
0.90 |
| ICU length of stay before BAL < 5 days | 46 (82.1) | 42 (85.7) |
221 (58.5) Missing values: n = 1 |
< 0.01 |
| Underlying respiratory diseases | ||||
| Cigarette smoking | 11 (19.6) | 8 (16.3) | 112 (29.6) | 0.06 |
| Chronic restrictive pulmonary disease | 4 (7.1) | 4 (8.2) | 41 (10.8) | 0.62 |
| Chronic obstructive pulmonary disease | 8 (14.3) | 13 (26.5) | 77 (20.4) | 0.30 |
| Asthma | 6 (10.7) | 2 (4.1) | 11 (2.9) | 0.02 |
| Home oxygen therapy | 0 | 1 (2) | 14 (3.7) | 0.30 |
| Sleep apnea syndrome | 6 (10.7) | 3 (6.1) | 31 (8.2) | 0.69 |
| Home positive pressure ventilation | 2 (3.6) | 2 (4.1) | 24 (6.3) | 0.61 |
| Immunosuppression | ||||
| All causes | 34 (60.7) | 36 (73.5) | 174 (46) | < 0.01 |
| Active solid organ cancer | 6 (10.7) | 10 (20.4) | 48 (12.7) | 0.27 |
| Hematological malignancy | 19 (33.9) | 14 (28.6) | 63 (16.7) | < 0.01 |
| Radiotherapy or chemotherapy within the past 6 months | 22 (39.3) | 15 (30.6) | 77 (20.4) | < 0.01 |
| Neutropeniaf | 6 (10.7) | 6 (12.2) | 23 (6.1) | 0.17 |
| HIV-positive | 3 (5.4) | 1 (2) | 11 (2.9) | 0.56 |
| Solid organ transplantation | 10 (17.9) | 9 (18.4) | 42 (11.1) | 0.16 |
| Corticosteroid therapy | 13 (23.2) | 14 (28.6) | 71 (18.8) | 0.23 |
| Others immunosuppressive drugs | 15 (26.3) | 24 (49) | 88 (23.3) | < 0.01 |
| Anticoagulant therapy | ||||
| Curative anticoagulant therapyg | 9 (15.8) | 12 (24.5) | 68 (18) | 0.47 |
| Anticoagulant therapy for venous thromboembolism prevention | 17 (30.4) | 17 (34.7) | 154 (40.7) | 0.27 |
| Antiplatelet therapy (including aspirin) | 7 (12.3) | 4 (8.2) | 75 (19.9) | 0.07 |
| Indications for BALh | ||||
| Community-acquired pneumonia | 25 (44.6) | 27 (55.1) | 141 (37.3) | 0.04 |
| Suspicion of hospital-acquired lung infection | 11 (19.6) | 8 (16.3) | 202 (53.4) | < 0.01 |
| Including hospital- or ventilator-associated pneumonia as the sole indication | 6 (10.7) | 2 (4.1) | 125 (33.1) | < 0.01 |
| Suspicion of diffuse parenchymal lung disease | 20 (35.7) | 29 (59.2) | 104 (27.5) | < 0.01 |
| Lung infiltrate of possible non-infectious origin | 17 (30.4) | 11 (22.4) | 72 (19) | 0.14 |
| Other indication | 7 (12.5) | 4 (8.2) | 42 (11.1) | 0.77 |
| Arterial blood gas analysis within 6 h before BAL | Missing values: n = 11 | Missing values: n = 1 | Missing values: n = 13 | |
| pH | 7.45 (7.42–7.47) | 7.46 (7.43–7.48) | 7.38 (7.31–7.45) | < 0.01 |
| PaCO2 (mmHg) | 35.0 (31.6–40) | 36.6 (32.5–41) | 42 (37.0–50.9) | < 0.01 |
| PaO2 (mmHg) | 73.0 (64.8–89) | 75.00 (59.8–97.4) | 80.6 (67–98) | 0.07 |
| PaO2/FiO2 ratio | 203 (147–326)i | 135 (102–183) | 150 (103–228) | < 0.01 |
| Initial clinical characteristics | ||||
| Lowest SpO2 (%) within 6 h before BAL | 95 (91–97) | 93 (90–96) | 95 (91–98) | 0.11 |
| Highest respiratory rate within 6 h before BAL | 27 (23–30) |
25 (23–31) Missing values: n = 2 |
25 (22–32) Missing values: n = 3 |
0.95 |
| Blood lactate (mmol/l) within 6 h before BAL |
1.3 (0.8–1.8) Missing values: n = 17 |
1.3 (0.9–1.8) Missing values: n = 6 |
1.5 (1.1–2.2) Missing values: n = 37 |
0.02 |
| Vital signs at H0j | ||||
| Body temperature (°C) |
37.4 (1) Missing values: n = 3 |
37.4 (0.8) Missing values: n = 2 |
37.3 (1.1) Missing values: n = 12 |
0.85 |
| Respiratory rate (cycles/min) |
24 (6) Missing values: n = 1 |
25 (6) |
24 (8) Missing values: n = 5 |
0.74 |
| Heart rate (b./min) | 100 (22) | 98 (22) | 99 (23) | 0.91 |
| SpO2 (%) | 96 (4) |
97 (3) Missing values: n = 1 |
97 (7) Missing values: n = 4 |
0.47 |
| Mean arterial blood pressure (mmHg) | 91 (19) | 86 (18) |
78 (16) Missing values: n = 2 |
< 0.01 |
| BAL procedure | ||||
| Amount of fluid instilled (ml) | 150 (100–150) | 150 (120–150) |
150 (100–150) Missing values: n = 11 |
0.15 |
| Amount of fluid recovered (ml) | 48 (30–69) | 40 (30–70) |
45 (30–60) Missing values: n = 11 |
0.92 |
| Duration of the BAL procedure (min) |
12 (9–15) Missing values: n = 2 |
10 (8–15) Missing values: n = 1 |
15 (10–20) Missing values: n = 19 |
< 0.01 |
| Time taken for BAL fluid to reach the laboratory | Missing values: n = 1 | Missing values: n = 7 | ||
| Less than 2 h | 46 (82.1) | 45 (91.8) | 290 (76.7) | 0.58 |
| Between 2 and 4 h | 3 (5.4) | 1 (2) | 37 (9.8) | 0.14 |
| More than 4 h | 6 (10.7) | 3 (6.1) | 44 (11.6) | 0.51 |
| Specialty and experiencek of the physician performing the bronchoscopy and BAL | ||||
| Pulmonologist | 37 (66.1) | 37 (75.5) | 126 (33.3) | < 0.01 |
| Intensivist | 19 (33.9) | 12 (24.5) | 252 (66.7) | < 0.01 |
| Experienced physicianl | 45 (80.4) | 43 (87.8) | 205 (54.2) | 0.01 |
SAPSII Simplified Acute Physiology Score, ICU intensive care unit, BAL bronchoalveolar lavage
aIncluding 45 (80.4%) patients under oxygen therapy via standard nasal cannula or non-rebreathing mask, and 11 patients (19.6%) under oxygen therapy via rebreathing mask
bIncluding only four patients (8.2%) under non-invasive ventilation
cGroups were compared using χ2 test for proportions, Kruskal–Wallis rank sum test or one-way analysis of variance for continuous variables. p values were non adjusted for multiple testing and should be considered exploratory
dCategorical variables are expressed as count and (%)
eContinuous variables are expressed as median (interquartile range) or mean (SD)
fAbsolute neutrophil count < 1000/µL
gAnticoagulant therapy for either recent thromboembolic event or for prevention of arterial thromboembolism (e.g., atrial fibrillation, mechanical heart valve, etc.)
hMore than one indication could be present for each BAL
iSignificantly higher than in the nasal high-flow oxygen therapy or non-invasive ventilation group (p < 0.001), and then in the invasive mechanical ventilation group (p = 0.001)
jH0 indicates the time at which BAL has began
kExperience in years in the specialty and in terms of number of BAL performed are detailed in Table S1 of the Online resource 1
lWe defined the physician performing the BAL as an “experienced physician” when he/she was a pulmonologist or when he/she was an intensivist with the greatest experience (i.e., > 10 years in the specialty or > 50 BAL performed)