Clinical characteristics and symptoms on admission of patients with a successful diagnostic procedure compared to patients without aetiology
| Parameter | No aetiology | Probable or definite aetiology | p-value | 95% CI of the difference |
| Patients n | 82/204 (40) | 122/204 (60) | ||
| Pa,O2/FI,O2 mmHg | 262±66 | 264±66 | 0.840 | −21.7–17.6 |
| Body temperature °C | 37.6±1.1 | 37.8±1.1 | 0.124 | −0.5–0.1 |
| Respiratory rate bpm | 31.4±8.0 | 30.0±9.6 | 0.285 | −1.2–4.0 |
| Duration of symptoms days | 4.5±4.0 | 4.7±6.6 | 0.751 | −1.9–1.4 |
| Acute respiratory failure | 55/82 (67) | 72/122 (59) | 0.244 | −5.4–21.4 |
| Septic shock | 12/82 (15) | 28/122 (23) | 0.142 | −2.7–18.7 |
| Serum creatinine mg·dL−1 | 1.5±1.5 | 1.2±0.8 | 0.081 | −0.1–0.6 |
| Serum albumin mg·dL−1 | 33.1±4.5 | 33.1±7.4 | 0.995 | −2.0–2.0 |
| ICU admission | 9/82 (11) | 20/122 (16) | 0.277 | −4.4–14.4 |
| Mechanical ventilation | 6/82 (7) | 16/122 (13) | 0.191 | −2.1–14.1 |
| Type of radiological infiltrate | ||||
| Bilateral | 28/82 (34) | 40/122 (33) | 0.840 | −12.2–14.2 |
| Alveolar | 48/78 (62) | 91/121 (75) | 0.040 | −0.3–26.3 |
| Interstitial | 6/78 (8) | 10/121 (8) | 0.884 | −7.7–7.7 |
| Mixed | 24/78 (30) | 20/121 (17) | 0.018 | 0.8–25.2 |
| Pleural effusion | 14/79 (18) | 16/116 (14) | 0.455 | −6.6–14.6 |
| Cough | 63/82 (78) | 92/122 (75) | 0.697 | −8.8–14.8 |
| Dyspnoea | 63/82 (77) | 84/122 (69) | 0.213 | −4.3–20.3 |
| Pleuritic chest pain | 25/82 (31) | 53/122 (44) | 0.056 | −0.3–26.3 |
| Chills | 29/82 (35) | 60/122 (49) | 0.051 | 0.4–27.6 |
| Preceding symptoms of upper airways infections | 33/81 (41) | 37/118 (31) | 0.173 | −3.6–23.6 |
Data are presented as n/total n (%) or mean±sd
CI: confidence interval
Pa,O2: oxygen tension in arterial blood
FI,O2: inspiratory oxygen fraction
ICU: intensive care unit
Clinical characteristics and symptoms on admission of patients. The exact numbers are given for each parameter, since information was not available for all patients.