Table A8.
Subgroup of 13,801 patients who were treated in public hospital ICUs – baseline characteristics by category of percentage of critical care registered nurses (CCRN) in each ICU.
| <50 % CCRN |
50–75% CCRN |
>75% CCRN |
p value | |
|---|---|---|---|---|
| N = 2350 | N = 7274 | N = 4177 | ||
| Age in years | 60.7 (18.0) | 60.8 (17.5) | 59.1 (17.6) | <0.001 |
| Men | 1395 (59.4%) | 4245 (58.4%) | 2520 (60.3%) | 0.11 |
| Source of admission to ICU | <0.001 | |||
| Operating theatre | 749 (31.9%) | 2361 (32.5%) | 1521 (36.4%) | |
| Emergency department | 1064 (45.3%) | 3115 (42.8%) | 1577 (37.8%) | |
| Hospital ward | 334 (14.2%) | 1164 (16.0%) | 594 (14.2%) | |
| Other hospital | 196 (8.3%) | 613 (8.4%) | 467 (11.2%) | |
| Other/unknown admission source | 7 (0.3%) | 21 (0.3%) | 18 (0.4%) | |
| Admission category | <0.001 | |||
| Emergency surgical admission | 406 (17.3%) | 1320 (18.1%) | 780 (18.7%) | |
| Medical ICU admission | 1592 (67.7%) | 4864 (66.9%) | 2548 (61.0%) | |
| Planned ICU admission after elective surgery | 352 (15.0%) | 1090 (15.0%) | 849 (20.3%) | |
| ICU admission diagnosis | <0.001 | |||
| Cardiac medical diagnoses | 305 (13.0%) | 934 (12.8%) | 456 (10.9%) | |
| Respiratory medical diagnoses (excl. pneumonia) | 212 (9.0%) | 648 (8.9%) | 263 (6.3%) | |
| Sepsis and other infections (incl. pneumonia) | 423 (18.0%) | 1350 (18.6%) | 696 (16.7%) | |
| Other medical diagnoses (incl. overdose) | 360 (15.3%) | 1160 (15.9%) | 578 (13.8%) | |
| Cardiothoracic & vascular surgery | 139 (5.9%) | 484 (6.7%) | 312 (7.5%) | |
| Coronary artery bypass and/or valve surgery | 131 (5.6%) | 457 (6.3%) | 501 (12.0%) | |
| Gastro-intestinal surgery | 201 (8.6%) | 656 (9.0%) | 356 (8.5%) | |
| Neurological and neurosurgical diagnoses | 118 (5.0%) | 471 (6.5%) | 404 (9.7%) | |
| Orthopaedic surgery | 44 (1.9%) | 108 (1.5%) | 55 (1.3%) | |
| Trauma | 271 (11.5%) | 561 (7.7%) | 339 (8.1%) | |
| Other surgical diagnoses | 146 (6.2%) | 445 (6.1%) | 217 (5.2%) | |
| COVID-19 pneumonitis | 105 (4.5%) | 291 (4.0%) | 97 (2.3%) | <0.001 |
| Comorbidities and frailty | ||||
| Diabetes | 549 (23.4%) | 1918 (26.4%) | 1058 (25.3%) | 0.014 |
| Chronic - cardiovascular | 149 (6.3%) | 389 (5.3%) | 117 (2.8%) | <0.001 |
| Chronic - respiratory | 198 (8.4%) | 707 (9.7%) | 211 (5.1%) | <0.001 |
| Chronic - dialysis dependent | 63 (2.7%) | 346 (4.8%) | 138 (3.3%) | <0.001 |
| Chronic - liver disease (cirrhosis) | 50 (2.1%) | 288 (4.0%) | 141 (3.4%) | <0.001 |
| Frailty category | <0.001 | |||
| Not frail (CFS1-3) | 1394 (59.3%) | 4208 (57.8%) | 1976 (47.3%) | |
| Pre-frail (CFS 4,5) | 742 (31.6%) | 2233 (30.7%) | 1099 (26.3%) | |
| Frail (CFS 6–8) | 168 (7.1%) | 567 (7.8%) | 214 (5.1%) | |
| Frailty unknown | 46 (2.0%) | 266 (3.7%) | 888 (21.3%) | |
| Illness severity scores | ||||
| APACHE II score | 16.4 (7.7) | 16.9 (7.6) | 14.8 (8.1) | <0.001 |
| APACHE III score | 54.1 (25.8) | 56.8 (25.4) | 54.7 (25.5) | <0.001 |
| ANZROD percent | 10.9 (18.5) | 12.0 (19.1) | 12.6 (20.5) | 0.002 |
| ANZROD percent | 2.9 (0.7–11.2) | 3.4 (0.9–13.7) | 3.3 (0.9–13.7) | <0.001 |
| Therapies provided in ICU | ||||
| Invasive ventilation | 900 (38.3%) | 3002 (41.3%) | 2065 (49.4%) | <0.001 |
| Renal replacement therapy | 163 (7.0%) | 553 (7.8%) | 259 (7.7%) | 0.46 |
| ECMO | 32 (1.4%) | 44 (0.6%) | 12 (0.4%) | <0.001 |
| Inotropes | 1030 (44.2%) | 3668 (51.8%) | 1823 (55.2%) | <0.001 |
| Hospital Classification | <0.001 | |||
| Rural/regional (4 ICUs) | 702 (30%) | 1179 (16%) | 190 (5%) | |
| Metropolitan (6 ICUs) | 748 (32%) | 2599 (36%) | 676 (16%) | |
| Tertiary (5 ICUs) | 900 (38%) | 3496 (48%) | 3311 (79%) | |
| Primary outcome | ||||
| In-hospital mortality | 251 (10.7%) | 844 (11.6%) | 425 (10.2%) | 0.054 |
| Secondary outcomes | ||||
| In-ICU mortality | 179 (7.6%) | 586 (8.1%) | 314 (7.5%) | 0.54 |
| Delirium in ICU | 258 (12.9%) | 611 (10.4%) | 93 (5.6%) | <0.001 |
| Pressure injury developed in ICU | 57 (2.7%) | 135 (2.3%) | 44 (2.6%) | 0.46 |
| Duration of ICU stay (days) | 2.2 (1.1–4.8) | 2.2 (1.1–4.4) | 2.0 (1.0–3.7) | <0.001 |
| Ratio of observed to predicted length of ICU stay | 1.18 (0.66–2.16) | 1.12 (0.65–1.97) | 0.95 (0.56–1.62) | <0.001 |
| Duration of stay in hospital (days) | 7.8 (3.8–14.8) | 8.3 (4.3–15.9) | 8.3 (4.3–15.5) | <0.001 |
| After-hours discharge from ICUa | 552 (25.4%) | 1555 (23.3%) | 725 (18.8%) | <0.001 |
APACHE, Acute Physiology and Chronic Health Evaluation; ANZROD, Australian & New Zealand Risk of Death; ICU, Intensive Care Unit. A vacant ICU bed is one that is not occupied by a patient but is available, equipped and can be staffed with 1:1 nursing ratio. A staffed ICU bed is equipped and can be staffed with 1:1 nursing ratio but may or may not be filled by a patient.
aData reported as mean (standard deviation).
bMedian (interquartile range); all other data reported as number (percentage).