Table 1.
Characteristics and outcomes of patients included in the study
| Variable | No Ventilation (n = 12,676; 91.0%) | Initial NIV (n = 556; 4.0%) | Initial IMV (n = 698; 5.0%) | P Value |
|---|---|---|---|---|
| Patient characteristics | ||||
| Age, median (IQR), yr | 53 (42–67) | 53 (43–68) | 53 (40–64) | 0.09 |
| Female, % | 73.6 | 69.2 | 65.8 | <0.001 |
| Race/ethnicity, % | ||||
| White | 54.8 | 51.3 | 48.9 | |
| Black | 34.5 | 37.9 | 41.6 | |
| Hispanic | 4.3 | 4.0 | 3.2 | <0.001 |
| Asian/other | 4.8 | 6.7 | 4.6 | |
| Unknown | 1.7 | 0.2 | 1.9 | |
| Smoking | 36.8 | 47.1 | 39.3 | <0.001 |
| Combined score | 1 (1–2) | 2 (1–3) | 2 (1–4) | <0.001 |
| Comorbidities, %* | ||||
| CHF | 10.5 | 23.0 | 24.4 | <0.001 |
| Valvular disease | 3.3 | 6.7 | 4.3 | <0.001 |
| Pulm. circ. disease | 0.7 | 6.7 | 6.0 | <0.001 |
| Neuro disorders | 5.3 | 4.5 | 13.5 | <0.001 |
| Diabetes mellitus | 24.6 | 27.2 | 23.9 | 0.35 |
| Hypothyroidism | 9.3 | 9.0 | 5.9 | 0.009 |
| Renal failure | 5.6 | 7.6 | 9.9 | <0.001 |
| Obesity | 16.6 | 19.1 | 16.6 | 0.30 |
| Morbid obesity | 6.5 | 9.2 | 5.6 | 0.03 |
| Anemia | 9.9 | 13.7 | 17.3 | <0.001 |
| Alcohol abuse | 2.4 | 5.9 | 6.5 | <0.001 |
| Drug abuse | 5.8 | 11.5 | 14.0 | <0.001 |
| Psychoses | 5.4 | 7.6 | 7.2 | 0.02 |
| Hypertension | 40.2 | 39.0 | 35.5 | 0.05 |
| Pneumonia POA | 8.0 | 13.1 | 24.1 | <0.001 |
| Status asthmaticus | 0.8 | 5.6 | 14.6 | <0.001 |
| Principal diagnosis of ARF | 7.4 | 38.1 | 72.3 | <0.001 |
| Principal diagnosis of asthma | 92.6 | 61.9 | 27.7 | |
| ICD-9 of chronic obstructive asthma | 43.7 | 58.3 | 48.7 | <0.001 |
| No ICD-9 of chronic obstructive asthma | 56.3 | 41.7 | 51.3 | |
| LAPS | ||||
| 0–19 | 12.9 | 7.2 | 2.4 | |
| 20–24 | 27.6 | 15.0 | 11.9 | |
| 25–30 | 22.0 | 10.9 | 6.9 | <0.001 |
| 31–41 | 22.7 | 22.0 | 12.9 | |
| 42+ | 14.9 | 44.9 | 65.9 | |
| Admitted to ICU, % | 12.7 | 16.0 | 39.8 | |
| Baro/volutrauma, %† | 0.2 | 0.5 | 3.4 | <0.001 |
| AMI not present at admission, % | 0.2 | 0.5 | 3.0 | <0.001 |
| LOS, d | 2.9 (1.8–4.7) | 4.1 (2.7–6.9) | 6.7 (3.8–11.5) | <0.001 |
| Inpatient case-fatality rate | 0.2% | 2.3% | 14.5% | <0.001 |
Definition of abbreviations: AMI = acute myocardial infarction; ARF = acute respiratory failure; CHF = congestive heart failure; ICD-9 = International Classification of Disease, Ninth Revision, Clinical Modification; ICU = intensive care unit; IMV = invasive mechanical ventilation; IQR = interquartile range; LAPS = Laboratory Acute Physiology Score; LOS = length of stay; NIV = noninvasive ventilation; POA = present on admission.
Additional comorbidities present in less than 5% of the sample: peripheral vascular disease, liver disease, peptic ulcer disease with bleeding, AIDS, lymphoma, metastatic cancer, solid tumor without metastasis, rheumatoid arthritis, coagulopathy.
Complications include: pneumothorax, subcutaneous emphysema, and subcutaneous emphysema from procedure.