Table 1.
Patient characteristics used in the full and test data sets. Values are mean (sd) or number of procedures (%). ‘Induction’ refers to the period between the start of anaesthesia and the start of surgery. ‘Maintenance’ spans the surgery duration. ‘Emergence’ is the time between the end of surgery and the end of anaesthesia. The choice of vitals appearing here is based on the vitals that appear as most contributive to the model's predictions (see Fig. 3). Here, the average value of the depth of MAP is below 65 mm Hg, each weighted by the time until the next measurement. For medications that are represented as counts (number of times given during surgery or initiated for infusions), means refer to the mean of the count across the patient sample. ENT, ear, nose and throat; IQR, inter-quartile range; sd, standard deviation; TWA, time-weighted average.
| Full data set, n=104 875 | Test data set, n=17 029 | |
|---|---|---|
| Demographics | ||
| PACU hypotension, n (%) | 12 601 (12.0) | 1943 (11.4) |
| Age, yr, median (IQR) | 54 (26) | 54 (25) |
| Facility, n (%) | 52 516 (50) | 8613 (51) |
| Female sex, n (%) | 50 279 (48) | 8112 (48) |
| Race, n (%) | ||
| White | 83 721 (80) | 13 832 (81) |
| Black/African American | 7922 (8) | 1263 (7) |
| Asian | 6907 (7) | 1040 (6) |
| American Indian | 2827 (3) | 448 (3) |
| Other | 3190 (3) | 427 (3) |
| Procedure details | ||
| Emergency status, n (%) | 6356 (6) | 838 (5) |
| ASA physical status, n (%) | ||
| 1 | 11 372 (11) | 1322 (8) |
| 2 | 47 773 (46) | 7041 (41) |
| 3 | 41 334 (39) | 7766 (46) |
| ≥4 | 4396 (4) | 900 (5) |
| Surgical specialty, n (%) | ||
| Orthopaedic | 30 515 (29) | 4786 (28) |
| General | 18 071 (17) | 2748 (16) |
| Urology | 10 738 (10) | 1964 (12) |
| ENT | 8667 (8) | 1493 (9) |
| Gynaecology | 7516 (7) | 1082 (6) |
| Ophthalmology | 6700 (6) | 1016 (6) |
| Neurology | 5795 (6) | 1008 (6) |
| Plastic | 4848 (5) | 882 (5) |
| Vascular | 2522 (2) | 568 (3) |
| Oral and maxillofacial | 2306 (2) | 303 (2) |
| Thoracic | 2304 (2) | 532 (3) |
| Other | 3887 (4) | 481 (3) |
| Comorbidities | ||
| BMI, kg m-2, mean (sd) | 28.8 (7.5) | 28.9 (7.9) |
| Diabetes mellitus, n (%) | 16 968 (16) | 3214 (19) |
| Hypertension, n (%) | 9138 (9) | 1394 (8) |
| Vitals | ||
| Diastolic BP (mm Hg) | ||
| Induction (mean) | 67 (12) | 67 (12) |
| Maintenance (mean) | 64 (12) | 65 (12) |
| Emergence (mean) | 71 (16) | 71 (16) |
| MAP (mm Hg) | ||
| Induction (mean) | 82 (13) | 83 (13) |
| Maintenance (mean) | 79 (12) | 80 (12) |
| Emergence (mean) | 87 (17) | 87 (17) |
| Systolic BP (mm Hg) | ||
| Induction (mean) | 114 (18) | 115 (18) |
| Maintenance (mean) | 111 (16) | 112 (16) |
| Emergence (mean) | 121 (22) | 121 (22) |
| Drugs | ||
| Vasopressor infusion i.v. count, median (IQR) | 0 (1) | 0 (2) |
| Opioid infusion i.v. count, median (IQR) | 0 (0) | 0 (0) |
| Anti-emetic bolus i.v. count, median (IQR) | 1 (1) | 2 (1) |
| Other | ||
| Estimated blood loss (ml), median (IQR) | 5 (50) | 5 (50) |
| Intraoperative hypotension (TWA; mm Hg ∗ h), median (IQR) | 0.5 (1.6) | 0.5 (1.5) |