Table 1.
Matched variables for the study groupsa.
| Without ECMO | With ECMO | |||
|---|---|---|---|---|
| Mean | (95% CI) | Mean | (95% CI) | |
|
| ||||
| Age | 50.0 | (47.7–52.3) | 49.9 | (47.1–52.5) |
|
| ||||
| N | % (95% CI) | N | % (95% CI) | |
|
| ||||
| Injury Severity Score (0–15) a | 800 | 99.4 (96.9–99.9) | 796 | 99.3 (96.0–99.0) |
| Sex | ||||
| Male | 551 | 68.5 (61.6–74.6) | 548 | 68.4 (61.6–74.4) |
| Female | 254 | 31.5 (25.4–38.4) | 254 | 31.6 (25.6–38.4) |
| Season of admission | ||||
| Winter | 199 | 24.7 (19.5–30.8) | 204 | 25.5 (20.2–31.7) |
| Spring | 195 | 24.3 (18.8–30.8) | 185 | 23.0 (17.9–29.2) |
| Summer | 203 | 25.3 (19.8–31.7) | 202 | 25.2 (19.8–31.5) |
| Autumn | 207 | 25.7 (20.1–32.3) | 210 | 26.2 (20.9–32.3) |
| Admission day | ||||
| Monday–Friday | 596 | 74.0 (67.6–79.6) | 591 | 73.7 (67.1–79.3) |
| Saturday-Sunday | 209 | 26.0 (20.4–32.4) | 211 | 26.3 (20.7–32.9) |
| Median household income b | ||||
| $1–$37,999 | 113 | 14.1 (10.0–19.6) | 115 | 14.3 (10.2–19.7) |
| $38,000–$47,999 | 202 | 25.1 (19.7–31.4) | 210 | 26.2 (20.6–32.7) |
| $48,000–$63,999 | 184 | 22.9 (17.6–29.2) | 185 | 23.1 (17.8–29.4) |
| $64,000 or more | 305 | 37.9 (31.6–44.7) | 292 | 36.3 (30.1–43.1) |
| Primary expected payer | ||||
| Medicare & Medicaid | 385 | 47.9 (41.0–54.9) | 384 | 47.8 (41.0–54.7) |
| Private including HMO | 384 | 47.8 (40.9–54.7) | 383 | 47.8 (41.0–54.7) |
| Chronic condition | 805 | 100 | 802 | 100 |
| Procedure class | ||||
| Minor diagnostic | 438 | 54.5 (47.9–60.8) | 448 | 55.9 (49.1–62.4) |
| Minor therapeutic | 725 | 90.1 (85.3–93.4) | 722 | 90.1 (85.5–93.3) |
| Major therapeutic | 800 | 99.4 (96.4–99.9) | 796 | 99.3 (95.9–99.9) |
aPer agreement with HCUP, certain categories of primary expected payer, major diagnostic procedure class, and major trauma category Injury Severity Score were omitted from the table due to a variable count less than 10. bAccording to national quartile for patient ZIP Code derived from ZIP Code-demographic data obtained from Claritas.