Table 1 Statistically significant different clinical features of Calgary Health Region residents and nonresidents admitted to intensive care units, Alberta, Canada

APACHE II score (mean ± standard deviation)

24.90 ± 8.71 (n = 7704)

25.46 ± 8.16 (n = 4381)

25.10 ± 8.52 (n = 12,085)

< 0.001

APACHE II score = 25

3556/7704 (53.8%)

1818/4381 (58.5%)

5374/12,085 (55.5%)

< 0.0001

TISS score (mean ± standard deviation)

43.52 ± 18.78 (n = 7411)

48.94 ± 17.99 (n = 4260)

45.50 ± 18.67 (n = 11,671)

< 0.0001

Surgical patient

4600/7754 (59%)

3254/4420 (74%)

7854/12,174 (65%)

< 0.0001

Fever = 37.8°C

3683/7604 (48.4%)

2200/4343 (50.7%)

5883/11,947 (49.2%)

0.02

Hypothermia < 35°C

1413/7610 (18.6%)

950/4347 (21.9%)

2363/11,957 (19.8%)

< 0.0001

Shock

4551/7767 (58.6%)

2731/4426 (61.7%)

7282/12,193 (59.7%)

< 0.001

Tachycardia = 100/min

5059/7698 (65.7%)

2729/4381 (62.3%)

7788/12,079 (64.5%)

< 0.001

Median (interquartile range) respiratory rate/min

26 (20–33)

24 (18–30)

25 (19–32)

<0.0001