Adverse events and postoperative outcomes
| Variables | Low (n=7940) | Intermediate (n=20 075) | High (n=5825) | P value |
| Adverse events (%) | ||||
| Vasospasm | 13.0 | 37.9 | 55.3 | <0.001 |
| Hydrocephalus | 34.1 | 60.5 | 69.4 | <0.001 |
| Urinary tract infection | 1.3 | 16.4 | 46.5 | <0.001 |
| Post-procedural fever | 0.5 | 0.2 | 0.5 | 0.108 |
| Pressure ulcer | 0.0 | 1.4 | 4.0 | <0.001 |
| Sepsis | 0.4 | 6.6 | 13.8 | <0.001 |
| Cardiogenic shock | 0.3 | 1.4 | 1.5 | 0.002 |
| Cerebral infarction | 2.2 | 11.5 | 22.4 | <0.001 |
| Syndrome of inappropriate antidiuretic hormone secretion | 3.5 | 4.2 | 4.1 | 0.421 |
| Hypo-osmolar hyponatremia | 15.9 | 30.5 | 33.4 | <0.001 |
| Pulmonary embolism | 0.4 | 1.8 | 2.6 | <0.001 |
| Phlebitis | 0.3 | 0.8 | 1.1 | 0.045 |
| Acute deep vein thrombosis | 2.0 | 7.8 | 13.6 | <0.001 |
| Periprocedural stroke | 0.4 | 1.6 | 1.7 | 0.001 |
| Acute myocardial infarction | 1.3 | 3.2 | 3.8 | <0.001 |
| Acute respiratory failure | 14.2 | 47.3 | 66.4 | <0.001 |
| Acute kidney injury | 1.5 | 10.2 | 17.9 | <0.001 |
| Mechanical ventilation | 16.2 | 47.5 | 66.1 | <0.001 |
| Tracheostomy | 2.1 | 11.4 | 22.3 | <0.001 |
| Gastrostomy | 3.0 | 14.1 | 31.0 | <0.001 |
| Any adverse event | 59.9 | 92.4 | 99.2 | <0.001 |
| Number of adverse events | <0.001 | |||
| 0 | 48.7 | 14.4 | 3.3 | |
| 1 | 27.5 | 18.0 | 9.2 | |
| >1 | 23.8 | 67.6 | 87.6 | |
| Mortality (%) | 6.4 | 15.3 | 10.8 | <0.001 |
| Length of stay (days) | ||||
| Mean±SD | 11.7±8.2 | 18.7±14.1 | 26.6±20.1 | <0.001 |
| Median (IQR) | 11 (7–15) | 16 (11–23) | 22 (16–31) | <0.001 |
| Total cost of admission ($) | ||||
| Mean±SD | 62 888±37 757 | 99 670±63 446 | 134 937±80 331 | <0.001 |
| Median (IQR) | 55 247 (39 050–75 934) | 83 358 (56 981–122 835) | 112 881 (82 426–164 897) | <0.001 |
| Disposition (%) | <0.001 | |||
| Routine | 75.1 | 39.8 | 19.6 | |
| Non-routine | 17.3 | 44.4 | 69.4 | |
| Other | 7.6 | 15.7 | 11.1 |