Table 3. Characteristics of pneumonia at hospital admission.
| Variable | No IMV n = 510 |
IMV n = 154 |
p-value |
|---|---|---|---|
| Vital signs at hospital admission: | |||
| Respiratory rate (breaths/min) | 32±8 | 31±10 | 0·32 |
| Heart rate (beats/min) | 101±21 | 111±23 | <0·001 |
| Systolic blood pressure (mmHg) | 123±32 | 128±36 | 0·090 |
| Diastolic blood pressure (mmHg) | 68±16 | 73±19 | 0·006 |
| Laboratory data at hospital admission: | |||
| Creatinine (mg/dL) | 1·7±1·0 | 1·7±1·1 | 0·81 |
| C-reactive protein (mg/dL) | 21±13 | 22±14 | 0·59 |
| White blood cells (109 cell/L) | 15·0±9·3 | 13·5±7·5 | 0·066 |
| Hematocrite (%) | 40±6 | 38±8 | 0·055 |
| Platelets (109 cell/L) | 241±103 | 265±155 | 0·16 |
| PaO2/FiO2 (mmHg) | 236±66 | 213±84 | 0·005 |
| PaCO2 (mmHg) | 37±13 | 43±17 | <0·001 |
| Arterial pH | 7·42±0·09 | 7·36±0·13 | <0·001 |
| Serum Na+ (mEq/L) | 136±6 | 135±6 | 0·20 |
| Serum K+ (mEq/L) | 4·1±0·8 | 4·0±0·8 | 0·11 |
| Severity variables at hospital admission: | |||
| APACHE-II | 16±5 | 17±6 | 0·091 |
| PSI risk class IV-V | 424 (83) | 125 (81) | 0·57 |
| CURB-65 risk score 3–5 | 322 (63) | 76 (49) | 0·002 |
| Confusion/disorientation | 245 (48) | 73 (47) | 0·89 |
| Bacteremia | 71 (14) | 25 (16) | 0·48 |
| Multilobar infiltration | 231 (45) | 65 (42) | 0·50 |
| Pleural effusion | 69 (14) | 39 (26) | 0·001 |
| Acute renal failure | 290 (57) | 67 (44) | 0·004 |
| Septic shock | 140 (28) | 58 (38) | 0·015 |
Results are given as n (%) or mean±SD. Percentages calculated on non-missing data.
APACHE = acute physiology and chronic health evaluation; CURB-65 = confusion, elevated blood urea nitrogen, respiratory rate and blood pressure plus age ≥65 years; IMV = invasive mechanical ventilation; PSI = pneumonia severity index; SD = standard deviation.