Variation of recorded RRs (breaths per minute) among selected subgroups
| Results by key subgroups | Mean (SD) | Median (IQR) | CV (SD/mean) |
| Hospital day | |||
| Day of admission | |||
| Maximal RR | 22.0 (5.7) | 20 (20–22) | 0.26 |
| Minimal RR | 15.9 (2.3) | 16 (16–18) | 0.14 |
| 2 days before discharge (maximal RR)* | 20.3 (4.2) | 20 (18–20) | 0.21 |
| Day of discharge (maximal RR) | 19.3 (3.1) | 20 (18–20) | 0.16 |
| Principal diagnosis† | |||
| Cardiopulmonary diagnosis‡ | 24.4 (6.5) | 22 (20–26) | 0.27 |
| Non-cardiopulmonary diagnosis | 21.6 (5.4) | 20 (20–22) | 0.25 |
| Oxygen saturation† | |||
| <92% | 24.6 (7.3) | 22 (20–26) | 0.30 |
| ≥92% | 21.6 (5.2) | 20 (20–22) | 0.24 |
| Prior to ICU transfer§ | |||
| Patients with any diagnosis | 21.2 (5.1) | 20 (20–22) | 0.24 |
| Patients with respiratory failure | 22.3 (5.5) | 20 (20–24) | 0.25 |
| Age† (years) | |||
| ≥65 | 22.3 (5.9) | 20 (20–24) | 0.26 |
| <65 | 21.8 (5.5) | 20 (20–22) | 0.25 |
| Sex† | |||
| Female | 22.0 (5.6) | 20 (20–22) | 0.25 |
| Male | 21.1 (5.8) | 20 (20–23) | 0.26 |
| Hospital type† | |||
| Public hospital | 21.9 (5.5) | 20 (20–22) | 0.25 |
| Non-public hospital | 22.1 (5.8) | 20 (20–22) | 0.26 |
*Restricted to patients with hospital length of stay ≥4 days (n=26 223 hospitalisations).
†Maximum recorded RR on the first day of admission.
‡Cardiopulmonary diseases include pneumonia, sepsis, COPD exacerbation, asthma exacerbation, myocardial infarction and CHF exacerbation based on the AHRQ Clinical Classification Software.
§Maximum recorded RR for all patients on the day prior to transfer to the ICU from the general medicine wards (n=1318), and for the 352 patients the day prior to ICU transfer with a primary or secondary discharge diagnosis for respiratory failure.
CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; CV, coefficient of variation; ICU, intensive care unit; RR, respiratory rate.