1 Introduction
2 Materials and methods
2.1 Statistical methods
2.1.1 Predictive performance by receiver operating characteristics
2.1.2 Event rate analysis
2.1.3 Positive predictive value
3 Results
Summary statistics | Combined | Blinded | Unblinded |
---|---|---|---|
Monitoring time (min) | 202 [154, 258] | 202 [154, 246] | 202 [157, 266] |
Number of patients with hypotension (event) | 187 of 305 (61%) | 94 of 150 (62%) | 93 of 155 (60%) |
Total number of events in dataset | 649 | 337 | 312 |
Average number of events per patient | 1 [0, 3] | 1 [0, 4] | 1 [0, 3] |
Average duration of each event (min) | 2 [1, 5] | 3 [1, 5] | 2 [1, 4] |
Total duration of events per patient (min) | 2.3 [0, 9.4] | 3.5 [0, 12.3] | 1.7 [0, 7.3] |
Total duration of events per patient (%) | 1.1 [0, 5.0] | 1.6 [0, 7.4] | 0.8 [0, 3.5] |
Mean MAP under 65 mmHg per patient (mmHg) | 60 [58, 62] | 60 [57, 62] | 61 [58, 62] |
Area under 65 mmHg for MAP per patient (mmHg × min) | 11.9 [0, 64.4] | 18.0 [0, 79.1] | 9.3 [0, 49.3] |
Time weighted area (MAP < 65 mmHg) per patient (mmHg) | 0.05 [0, 0.35] | 0.08 [0, 0.53] | 0.04 [0, 0.24] |
3.1 Algorithm performance
Time | AUC [95% Conf] | Sensitivity | Specificity | Threshold |
---|---|---|---|---|
Combined (N = 305) | ||||
5 min | 0.93 [0.91,0.95] | 0.86 [0.82,0.89] | 0.86 [0.82,0.89] | 30 |
10 min | 0.90 [0.87,0.93] | 0.83 [0.79,0.86] | 0.83 [0.79,0.86] | 28 |
15 min | 0.84 [0.79,0.88] | 0.75 [0.71,0.80] | 0.75 [0.71,0.80] | 22 |
Blinded arm (N = 150) | ||||
5 min | 0.94 [0.90,0.96] | 0.86 [0.82,0.91] | 0.87 [0.82,0.91] | 30 |
10 min | 0.93 [0.88,0.96] | 0.87 [0.81,0.92] | 0.87 [0.81,0.91] | 28 |
15 min | 0.83 [0.75,0.89] | 0.75 [0.68,0.82] | 0.75 [0.68,0.81] | 22 |
Unblinded arm (N = 155) | ||||
5 min | 0.93 [0.91,0.95] | 0.86 [0.82,0.89] | 0.86 [0.82,0.89] | 31 |
10 min | 0.90 [0.87,0.93] | 0.83 [0.79,0.86] | 0.83 [0.79,0.86] | 31 |
15 min | 0.84 [0.79,0.88] | 0.75 [0.71,0.80] | 0.75 [0.71,0.80] | 22 |
HPI range | Event rate (95% CI), % | Median time to event (95% CI), min | 25th percentile time to event (95% CI), min | 75th percentile time to event (95% CI), min | Number of samples |
---|---|---|---|---|---|
Combined (N = 305) | |||||
0–9 | 9.9 [8.6, 11.3] | 9.7 [8.7, 10.3] | 6.3 [5.7, 7.0] | 12.3 [12.0, 13.0] | 5715/57,983 |
10–19 | 17.5 [15.4, 19.7] | 9.0 [8.3, 10.0] | 6.0 [5.3, 6.7] | 12.7 [12.0, 13.0] | 5689/32,581 |
20–29 | 27.4 [24.8, 30.3] | 8.7 [8.0, 9.0] | 5.3 [4.7, 6.0] | 11.7 [11.3, 12.3] | 6882/25,082 |
30–39 | 41.3 [38.0, 44.8] | 8.3 [8.0, 8.7] | 5.3 [5.0, 5.7] | 11.3 [11.0, 12.0] | 9635/23,286 |
40–49 | 54.7 [50.9, 58.4] | 7.4 [7.0, 8.1] | 4.7 [4.0, 5.0] | 10.7 [10.0, 11.0] | 5562/10,182 |
50–59 | 61.7 [57.6, 65.5] | 7.3 [6.7, 7.7] | 4.3 [4.0, 5.0] | 11.0 [10.0, 11.7] | 3843/6239 |
60–69 | 67.1 [62.9, 71.1] | 6.7 [6.0, 7.7] | 3.7 [3.3, 4.1] | 11.0 [10.0, 12.0] | 3601/5382 |
70–79 | 74.1 [70.0, 78.1] | 6.7 [5.7, 7.3] | 3.7 [3.3, 4.3] | 10.3 [9.7, 11.0] | 3396/4598 |
80–89 | 79.9 [75.9, 83.6] | 6.0 [5.3, 6.7] | 3.3 [3.0, 3.7] | 9.7 [9.0, 10.3] | 4091/5127 |
90–99 | 89.2 [86.3, 92.1] | 2.7 [2.3, 3.0] | 1.0 [1.0, 1.0] | 6.7 [6.0, 7.3] | 14,007/15,726 |
100 | 100 [100, 100] | 0 [0, 0] | 0 [0, 0] | 0 [0, 0] | 5690/5728 |
Blinded arm (N = 150) | |||||
0–9 | 9.9 [8.2, 11.9] | 9.7 [8.3, 10.7] | 6.3 [6.0, 7.0] | 12.3 [11.7, 13.0] | 2899/29,445 |
10–19 | 16.5 [13.5, 20.0] | 9 [7.7, 10.1] | 5.7 [5.0, 6.7] | 12.7 [11.3, 13.3] | 2616/15,875 |
20–29 | 25.1 [21.8, 28.8] | 8.7 [7.7, 9.3] | 5.3 [4.3, 6.1] | 12.0 [11.3, 12.3] | 2929/11,651 |
30–39 | 40.0 [35.2, 44.7] | 8.3 [7.7, 9.0] | 5.3 [5.0, 5.7] | 11.3 [10.7, 12.0] | 4540/11,392 |
40–49 | 54.0 [48.2, 59.6] | 7.3 [6.7, 8.3] | 4.3 [4.0, 5.0] | 10.3 [9.8, 11.3] | 2490/4625 |
50–59 | 63.8 [58.6, 69.3] | 7.7 [6.7, 8.7] | 4.3 [3.7, 5.3] | 11.3 [10.0, 12.0] | 1749/2742 |
60–69 | 68.7 [63.9, 74.1] | 7.7 [6.3, 8.3] | 3.7 [3.3, 4.7] | 11.3 [10.3, 12.3] | 1623/2357 |
70–79 | 74.6 [69.3, 80.2] | 6.7 [6.0, 8.0] | 3.7 [3.0, 4.7] | 10.7 [9.3, 11.3] | 1578/2116 |
80–89 | 79.7 [73.0, 85.9] | 6.3 [5.3, 7.3] | 3.3 [3.0, 4.0] | 10.0 [8.8, 11.0] | 1842/2317 |
90–99 | 90.2 [86.3, 93.8] | 2.7 [2.3, 3.0] | 1 [1.0, 1.3] | 6.7 [6.0, 7.7] | 6786/7536 |
100 | 100 [100, 100] | 0 [0, 0] | 0 [0, 0] | 0 [0, 0] | 3292/3292 |
Unblinded arm (N = 155) | |||||
0–9 | 9.9 [8.1, 11.9] | 9.3 [8.0, 10.7] | 6.0 [4.8, 7.3] | 12.3 [11.7, 13.3] | 2828/28,512 |
10–19 | 18.5 [15.6, 21.4] | 9.0 [8.0, 10.7] | 6.0 [5.3, 7.3] | 12.3 [11.7, 13.0] | 3073/16,696 |
20–29 | 29.6 [25.2, 33.9] | 8.3 [7.7, 9.5] | 5.7 [4.7, 6.3] | 11.7 [10.7, 12.3] | 3947/13,404 |
30–39 | 43.1 [38.4, 47.5] | 8.3 [7.7, 9.0] | 5.2 [4.3, 5.7] | 11.6 [11.0, 12.3] | 5068/11,819 |
40–49 | 55.5 [50.7, 60.3] | 7.7 [6.7, 8.7] | 4.7 [4.0, 5.3] | 10.7 [10.0, 11.3] | 3064/5524 |
50–59 | 60.2 [53.9, 66.0] | 7.0 [6.0, 7.8] | 4.3 [4.1, 5.0] | 10.7 [9.6, 11.7] | 2087/3466 |
60–69 | 66.0 [59.7, 72.4] | 6.0 [5.3, 7.3] | 3.3 [3.0, 4.3] | 10.3 [8.7, 12.0] | 1974/2991 |
70–79 | 73.9 [68.4, 79.5] | 6.5 [5.3, 7.7] | 3.7 [3.0, 4.0] | 10.0 [9.0, 11.0] | 1815/2459 |
80–89 | 80.1 [75.3, 85.3] | 6.0 [5.0, 6.7] | 3.3 [2.7, 4.0] | 9.3 [8.0, 10.3] | 2238/2794 |
90–99 | 88.5 [83.9, 92.6] | 2.7 [2.3, 3.0] | 1.0 [1.0, 1.0] | 6.3 [5.0, 7.3] | 7232/8179 |
100 | 100 [100, 100] | 0 [0, 0] | 0 [0, 0] | 0 [0, 0] | 2425/2425 |