Patient demographics and comorbidities.
| Variables | Normal (n = 91) | Prolonged (n = 38) | P Value |
| Age, y | 0.755 | ||
| Mean ± SD | 14.1 ± 1.7 | 14.2 ± 2.2 | |
| Median (IQR) | 14.0 (13.0–15.0) | 14.0 (12.2–16.0) | |
| Female, n (%) | 72 (79.1) | 28 (73.7) | 0.497 |
| Race/ethnicity | |||
| Non-Hispanic white | 62 (68.1) | 30 (78.9) | 0.286 |
| Body mass index (kg/m2) | 0.916 | ||
| Mean ± SD | 22.0 ± 3.5 | 22.4 ± 5.4 | |
| Median (IQR) | 21.4 (19.4–23.5) | 21.2 (19.5–24.4) | |
| Comorbidities, n (%) | |||
| Affective disorder | 8 (8.8) | 3 (7.9) | >0.99 |
| Attention-deficit/hyperactivity disorder | 4 (4.4) | 3 (7.9) | 0.420 |
| Autism spectrum disorder | 4 (4.4) | 0 (0.0) | 0.319 |
| Congenital heart defect | 3 (3.3) | 1 (2.6) | >0.99 |
| Asthma | 21 (23.1) | 8 (21.1) | 0.984 |
| Anemia | 24 (27.3) | 9 (25.0) | 0.971 |
| Obesity | 13 (14.3) | 7 (18.4) | 0.745 |
| Hypothyroidism | 2 (2.2) | 0 (0.0) | >0.99 |
| Seizure disorder | 2 (2.2) | 1 (2.6) | >0.99 |
| Gastroesophageal reflux disease | 2 (2.2) | 1 (2.6) | >0.99 |
| Eczema | 6 (6.6) | 1 (2.6) | 0.673 |
| Number of allergies, n (%) | 0.885 | ||
| 0 | 52 (57.1) | 23 (60.5) | |
| 1 | 24 (26.4) | 10 (26.3) | |
| >1 | 15 (16.5) | 5 (13.2) | |
| Preoperative laboratory values, mean ± SD | |||
| Hemoglobin, g/dL | 13.0 ± 1.1 | 13.2 ± 1.3 | 0.572 |
| Hematocrit, % | 38.8 ± 3.2 | 39.1 ± 4.0 | 0.657 |
| Albumin, g/dL | 4.4 ± 0.2 | 4.5 ± 0.3 | 0.373 |
| Platelets, ×1000 µL | 290.0 ± 62.3 | 298.0 ± 70.2 | 0.449 |
| Creatinine, mg/dL | 0.6 ± 0.2 | 0.6 ± 0.2 | 0.901 |
Abbreviation: IQR, interquartile range.