Table A4.
Comparison of patients at participating sites who could be linked to staffing data to those where linkage was not possible (admitted on days went no staffing information was submitted.
| No Staffing Data |
Staffing Data Available |
p value | |
|---|---|---|---|
| N = 1653 | N = 16,618 | ||
| Age in years | 62.6 (17.5) | 61.5 (17.4) | 0.012 |
| Men | 994 (60.1%) | 9651 (58.1%) | 0.11 |
| Source of admission to ICU | <0.001 | ||
| Operating theatre | 893 (54.0%) | 6766 (40.7%) | |
| Emergency department | 473 (28.6%) | 6000 (36.1%) | |
| Hospital ward | 193 (11.7%) | 2432 (14.6%) | |
| Other hospital | 83 (5.0%) | 1370 (8.2%) | |
| Other/unknown admission source | 11 (0.7%) | 50 (0.3%) | |
| Admission category | <0.001 | ||
| Emergency surgical admission | 264 (16.0%) | 2850 (17.2%) | |
| Medical ICU admission | 757 (45.8%) | 9677 (58.2%) | |
| Planned ICU admission after elective surgery | 632 (38.2%) | 4091 (24.6%) | |
| ICU admission diagnosis | <0.001 | ||
| Cardiac medical diagnoses | 116 (7.0%) | 1876 (11.3%) | |
| Respiratory medical diagnoses (excl. pneumonia) | 108 (6.5%) | 1206 (7.3%) | |
| Sepsis and other infections (incl. pneumonia) | 208 (12.6%) | 2646 (15.9%) | |
| Other medical diagnoses (incl. overdose) | 181 (10.9%) | 2290 (13.8%) | |
| Cardiothoracic & vascular surgery | 136 (8.2%) | 1248 (7.5%) | |
| Coronary artery bypass and/or valve surgery | 241 (14.6%) | 1530 (9.2%) | |
| Gastro-intestinal surgery | 193 (11.7%) | 1736 (10.4%) | |
| Neurological and neurosurgical diagnoses | 128 (7.7%) | 1149 (6.9%) | |
| Orthopaedic surgery | 129 (7.8%) | 619 (3.7%) | |
| Trauma | 131 (7.9%) | 1199 (7.2%) | |
| Other surgical diagnoses | 82 (5.0%) | 1119 (6.7%) | |
| COVID-19 pneumonitis | 42 (2.5%) | 508 (3.1%) | 0.24 |
| Comorbidities and frailty | |||
| Diabetes | 342 (20.7%) | 3904 (23.5%) | 0.010 |
| Chronic - cardiovascular | 163 (9.9%) | 932 (5.6%) | <0.001 |
| Chronic - respiratory | 115 (7.0%) | 1246 (7.5%) | 0.42 |
| Chronic - dialysis dependent | 42 (2.5%) | 613 (3.7%) | 0.017 |
| Chronic - liver disease (cirrhosis) | 21 (1.3%) | 486 (2.9%) | <0.001 |
| Frailty category | <0.001 | ||
| Not frail (CFS1-3) | 731 (44.2%) | 8177 (49.2%) | |
| Pre-frail (CFS 4,5) | 416 (25.2%) | 4574 (27.5%) | |
| Frail (CFS 6–8) | 98 (5.9%) | 1036 (6.2%) | |
| Frailty unknown | 408 (24.7%) | 2831 (17.0%) | |
| Illness severity scores | |||
| APACHE III/IV score | 52.2 (23.7) | 54.2 (24.7) | 0.002 |
| ANZROD percent | 7.7 (15.7) | 10.6 (18.4) | <0.001 |
| Hours in hospital prior to ICU admission | 10.1 (5.4–26.9) | 9.4 (4.8–24.5) | <0.001 |
| Therapies provided in ICU | |||
| Invasive ventilation | 654 (39.6%) | 6643 (40.0%) | 0.75 |
| Renal replacement therapy | 71 (4.7%) | 1016 (6.7%) | 0.002 |
| ECMO | 5 (0.3%) | 89 (0.6%) | 0.20 |
| Invasive ventilation, renal replacement or ECMO | 672 (40.7%) | 7000 (42.1%) | 0.25 |
| Inotropes | 658 (42.8%) | 7228 (47.9%) | <0.001 |
| No ventilation, renal replacement or ECMO | 981 (59.3%) | 9618 (57.9%) | 0.25 |
| Hospital classification | <0.001 | ||
| Public rural/regional (4 ICUs) | 180 (11%) | 2071 (12%) | |
| Public metropolitan (6 ICUs) | 266 (16%) | 4023 (24%) | |
| Public tertiary (5 ICUs) | 420 (25%) | 7707 (46%) | |
| Private (5 ICUs) | 787 (48%) | 2817 (17%) | |
| Characteristics of the ICU on day of admission | |||
| Baseline business-as-usual ICU beds | 11.0 (7.0–26.0) | 17.0 (10.0–26.0) | <0.001 |
| Number of open available ICU beds | 10.5 (6.0–17.0) | 12.3 (8.0–27.3) | <0.001 |
| Number of vacant ICU beds | 2.5 (1.3–4.3) | 1.8 (0.9–3.3) | <0.001 |
| Occupancy | 80.0 (66.0–91.0) | 88.0 (75.0–94.0) | <0.001 |
| Activity Index of the ICU | 1.0 (0.5–1.5) | 1.3 (0.8–1.6) | <0.001 |
| Number of ‘ICU equivalents' | 8.0 (3.5–14.0) | 10.5 (5.5–25.5) | <0.001 |
| Number of patients receiving 1:1 nursing in ICU | 6.0 (1.5–12.5) | 9.0 (3.5–24.0) | <0.001 |
| Number of ventilated patients in ICU | 2.0 (1.0–6.0) | 4.5 (1.3–13.5) | <0.001 |
| Number of COVID-19 patients in ICU | 1.0 (0.0–3.5) | 1.0 (0.0–3.0) | <0.001 |
| Number of patients on renal replacement therapy in ICU | 0.0 (0.0–2.0) | 1.0 (0.0–2.0) | <0.001 |
| Number of 1:2/HDU patients in ICU | 3.0 (1.7–5.0) | 3.0 (1.3–5.0) | 0.047 |
| Outcomes | |||
| In-hospital mortality | 143 (8.7%) | 1645 (9.9%) | 0.10 |
| In-ICU mortality | 103 (6.2%) | 1125 (6.8%) | 0.40 |
| Delirium in ICU | 117 (8.6%) | 1026 (8.6%) | 0.94 |
| Pressure injury developed in ICU | 30 (2.2%) | 238 (1.9%) | 0.52 |
| Duration of ICU stay (days) | 1.9 (1.0–3.4) | 2.0 (1.0–3.9) | 0.006 |
| Ratio of observed to predicted length of ICU stay | 1.09 (0.71–1.76) | 1.07 (0.65–1.84) | 0.36 |
| Duration of stay in hospital (days) | 8.5 (4.9–14.4) | 8.1 (4.2–15.1) | 0.25 |
| After-hours discharge from ICU (ICU survivors only) | 228 (14.7%) | 2959 (19.1%) | <0.001 |
APACHE, Acute Physiology and Chronic Health Evaluation; ANZROD, Australian & New Zealand Risk of Death. CCRN, Critical Care Registered Nurse; HDU, high-dependency unit; 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.