Table 2.
Probability of ECPR Use for Cardiac Arrest
| Variable | Risk Ratio (95% CI)a | P Value | Risk Ratio (95% CI)b | P Value | Risk Ratio (95% CI)c | P Value |
|---|---|---|---|---|---|---|
| Age, y | ||||||
| 40–59 | Reference | ··· | Reference | ··· | Reference | ··· |
| <40 | 1.5 (1.3–1.8) | <0.001 | 1.5 (1.3–1.9) | <0.001 | 1.5 (1.2–1.8) | <0.001 |
| ≥60 | 0.6 (0.5–0.7) | <0.001 | 0.6 (0.5–0.7) | <0.001 | 0.6 (0.5–0.7) | <0.001 |
| Sex | ||||||
| Male | Reference | ··· | Reference | ··· | Reference | ··· |
| Female | 0.9 (0.8–1.0) | 0.034 | 0.9 (0.8–1.0) | 0.022 | 0.9 (0.8–1.0) | 0.044 |
| Race | ||||||
| White | Reference | ··· | Reference | ··· | Reference | ··· |
| Black | 0.7 (0.6–0.8) | <0.001 | 0.8 (0.7–1.0) | 0.013 | 0.8 (0.7–1.0) | 0.020 |
| Other | 1.0 (0.8–1.2) | 0.96 | 1.0 (0.8–1.3) | 0.74 | 1.0 (0.8–1.3) | 0.84 |
| Hispanic ethnicity | 1.0 (0.7–1.3) | 0.96 | 1.0 (0.8–1.3) | 0.94 | 1.0 (0.7–1.3) | 1.00 |
| Weight, kg | 1.0 (1.0–1.0) | 0.31 | 1.0 (1.0–1.0) | 0.66 | 1.0 (1.0–1.0) | 0.65 |
| Pre‐existing conditions | ||||||
| None | 1.5 (1.2–1.9) | <0.001 | 1.5 (1.2–1.8) | 0.002 | 1.4 (1.1–1.8) | 0.004 |
| Preceding hypoperfusion | 1.8 (1.6–2.1) | <0.001 | 1.6 (1.4–1.8) | <0.001 | 1.6 (1.4–1.8) | <0.001 |
| CVA or neurologic disorder | 0.4 (0.3–0.5) | <0.001 | 0.5 (0.4–0.6) | <0.001 | 0.5 (0.4–0.6) | <0.001 |
| CHF | 1.2 (1.1–1.4) | <0.001 | 1.3 (1.1–1.5) | <0.001 | 1.3 (1.2–1.5) | <0.001 |
| Diabetes mellitus | 0.6 (0.5–0.7) | <0.001 | 0.7 (0.6–0.8) | <0.001 | 0.7 (0.6–0.8) | <0.001 |
| Hepatic insufficiency | 0.5 (0.4–0.7) | <0.001 | 0.6 (0.5–0.8) | <0.001 | 0.6 (0.5–0.8) | 0.001 |
| Major trauma | 0.8 (0.6–1.1) | 0.12 | 0.7 (0.5–1.0) | 0.06 | 0.7 (0.5–1.0) | 0.025 |
| Cancer | 0.3 (0.2–0.4) | <0.001 | 0.3 (0.2–0.5) | <0.001 | 0.3 (0.2–0.5) | <0.001 |
| History of MI | 1.5 (1.3–1.8) | <0.001 | 1.4 (1.2–1.6) | <0.001 | 1.3 (1.2–1.6) | <0.001 |
| MI this hospitalization | 2.1 (1.8–2.4) | <0.001 | 1.6 (1.3–1.8) | <0.001 | 1.5 (1.3–1.7) | <0.001 |
| Renal insufficiency | 0.5 (0.5–0.6) | <0.001 | 0.6 (0.5–0.7) | <0.001 | 0.6 (0.5–0.7) | <0.001 |
| Respiratory insufficiency | 0.8 (0.7–0.9) | 0.002 | 0.8 (0.7–0.9) | 0.004 | 0.8 (0.7–0.9) | 0.006 |
| Sepsis | 0.4 (0.3–0.5) | <0.001 | 0.5 (0.4–0.6) | <0.001 | 0.5 (0.4–0.6) | <0.001 |
| Admission CPCd | ||||||
| CPC 1 | Reference | ··· | Reference | ··· | Reference | ··· |
| CPC 2 | 0.4 (0.3–0.5) | <0.001 | 0.5 (0.4–0.6) | <0.001 | 0.5 (0.4–0.6) | <0.001 |
| CPC 3 | 0.3 (0.2–0.4) | <0.001 | 0.4 (0.3–0.5) | <0.001 | 0.4 (0.3–0.5) | <0.001 |
| CPC 4 | 0.7 (0.6–1.0) | 0.027 | 0.9 (0.7–1.2) | 0.34 | 0.9 (0.7–1.2) | 0.35 |
| Hospital beds | ||||||
| 1–100 | Reference | ··· | Reference | ··· | Reference | ··· |
| 101–199 | 1.1 (0.3–3.9) | 0.87 | 1.3 (0.4–4.6) | 0.64 | 1.3 (0.4–4.4) | 0.67 |
| 201–249 | 0.8 (0.2–2.7) | 0.67 | 0.9 (0.3–3.2) | 0.91 | 1.0 (0.3–3.5) | 0.95 |
| 251–299 | 0.5 (0.2–1.7) | 0.28 | 0.6 (0.2–2.1) | 0.44 | 0.5 (0.2–1.7) | 0.31 |
| 301–349 | 0.4 (0.1–1.5) | 0.19 | 0.5 (0.1–1.5) | 0.20 | 0.4 (0.1–1.5) | 0.19 |
| 351–499 | 0.4 (0.1–1.3) | 0.12 | 0.5 (0.1–1.5) | 0.19 | 0.4 (0.1–1.3) | 0.12 |
| ≥500 | 0.4 (0.1–1.4) | 0.16 | 0.5 (0.2–1.6) | 0.25 | 0.4 (0.1–1.2) | 0.11 |
| Annual admissions | ||||||
| 100–2499 | Reference | ··· | Reference | ··· | Reference | ··· |
| 2500–4999 | 1.8 (0.3–10.9) | 0.51 | 2.0 (0.3–12.3) | 0.44 | 0.9 (0.1–5.1) | 0.88 |
| 5000–7499 | 2.7 (0.6–13.2) | 0.22 | 3.4 (0.7–17.3) | 0.13 | 2.6 (0.5–12.7) | 0.23 |
| 7500–9999 | 0.7 (0.1–3.9) | 0.72 | 0.9 (0.2–4.8) | 0.89 | 0.6 (0.1–3.1) | 0.54 |
| 10 000–14 999 | 0.8 (0.2–3.2) | 0.72 | 0.9 (0.2–4.1) | 0.92 | 0.7 (0.2–2.9) | 0.60 |
| 15 000–19 999 | 0.7 (0.2–2.9) | 0.61 | 0.8 (0.2–3.5) | 0.76 | 0.5 (0.2–2.2) | 0.38 |
| 20 000–29 999 | 0.6 (0.1–2.5) | 0.48 | 0.7 (0.2–3.0) | 0.62 | 0.4 (0.1–1.9) | 0.27 |
| 30 000–39 999 | 0.5 (0.1–2.0) | 0.31 | 0.6 (0.1–2.6) | 0.48 | 0.3 (0.1–1.4) | 0.12 |
| ≥40 000 | 0.7 (0.2–2.8) | 0.56 | 0.8 (0.2–3.6) | 0.76 | 0.4 (0.1–1.9) | 0.26 |
| Cardiac ICU beds | ||||||
| ≥31 | Reference | ··· | Reference | ··· | Reference | ··· |
| 0 | 1.6 (1.0–2.7) | 0.054 | 1.7 (1.0–2.7) | 0.032 | 1.7 (1.1–2.8) | 0.027 |
| 1–5 | 1.4 (0.5–4.2) | 0.50 | 1.2 (0.4–3.8) | 0.72 | 1.0 (0.3–3.3) | 1.00 |
| 6–10 | 1.2 (0.7–2.0) | 0.57 | 1.1 (0.6–1.8) | 0.77 | 1.1 (0.7–1.8) | 0.73 |
| 11–15 | 0.9 (0.5–1.5) | 0.56 | 0.9 (0.5–1.5) | 0.64 | 0.9 (0.5–1.4) | 0.56 |
| 16–20 | 1.4 (0.8–2.4) | 0.21 | 1.3 (0.8–2.1) | 0.35 | 1.1 (0.7–1.8) | 0.78 |
| 21–30 | 1.7 (1.0–2.8) | 0.06 | 1.6 (1.0–2.6) | 0.07 | 1.6 (1.0–2.6) | 0.053 |
| Cardiac ICU beds/total beds (%) | ||||||
| 0.1 to <2.5 | Reference | ··· | Reference | ··· | Reference | ··· |
| 0 | 1.7 (1.1–2.8) | 0.026 | 1.8 (1.1–2.8) | 0.013 | 2.0 (1.3–3.2) | 0.003 |
| 2.5 to <5 | 1.2 (0.8–1.8) | 0.40 | 1.1 (0.8–1.7) | 0.52 | 1.1 (0.8–1.7) | 0.50 |
| 5 to <7.5 | 1.5 (0.9–2.5) | 0.09 | 1.5 (0.9–2.3) | 0.11 | 1.6 (1.0–2.5) | 0.052 |
| 7.5 to <10 | 2.7 (1.1–6.5) | 0.025 | 2.8 (1.2–6.3) | 0.017 | 3.1 (1.3–7.0) | 0.008 |
| ≥10 | 1.3 (0.5–3.4) | 0.61 | 1.2 (0.5–3.0) | 0.74 | 1.3 (0.5–3.3) | 0.58 |
| Geographic region of United States | ||||||
| North/Mid Atlantic | Reference | ··· | Reference | ··· | Reference | ··· |
| South Atlantic and Puerto Rico | 0.6 (0.4–0.9) | 0.008 | 0.6 (0.4–1.0) | 0.035 | 0.7 (0.4–1.0) | 0.06 |
| North Central | 0.9 (0.6–1.3) | 0.49 | 0.9 (0.6–1.4) | 0.75 | 1.0 (0.6–1.5) | 0.86 |
| South Central | 0.8 (0.5–1.2) | 0.27 | 0.9 (0.6–1.5) | 0.79 | 1.1 (0.7–1.7) | 0.78 |
| Mountain/Pacific | 1.1 (0.7–1.8) | 0.61 | 1.2 (0.8–1.9) | 0.41 | 1.3 (0.8–2.2) | 0.25 |
| Intensivist services on site | 1.5 (0.8–2.6) | 0.19 | 1.3 (0.7–2.3) | 0.35 | 1.1 (0.6–2.0) | 0.65 |
| Urban/rural location | ||||||
| Urban | Reference | ··· | Reference | ··· | Reference | ··· |
| Rural | 0.7 (0.3–1.7) | 0.49 | 0.8 (0.4–1.8) | 0.59 | 0.8 (0.4–1.7) | 0.55 |
| Teaching status | ||||||
| Major teaching | Reference | ··· | Reference | ··· | Reference | ··· |
| Minor teaching | 0.7 (0.5–1.0) | 0.050 | 0.8 (0.6–1.0) | 0.07 | 0.7 (0.5–1.0) | 0.025 |
| Nonteaching | 0.9 (0.5–1.5) | 0.65 | 0.9 (0.6–1.5) | 0.75 | 0.8 (0.5–1.3) | 0.36 |
| Medicare days | ||||||
| 0 | Reference | ··· | Reference | ··· | Reference | ··· |
| 1–1500 | 12.4 (3.5–43.4) | <0.001 | 8.6 (2.6–28.5) | <0.001 | 8.2 (2.4–27.4) | <0.001 |
| 1501–5000 | 6.8 (0.9–50.8) | 0.06 | 2.7 (0.4–17.9) | 0.31 | 2.7 (0.4–18.7) | 0.32 |
| 5001–20 000 | 1.3 (0.4–4.3) | 0.64 | 1.1 (0.3–3.3) | 0.93 | 0.9 (0.3–2.7) | 0.80 |
| >20 000 | 0.7 (0.2–1.8) | 0.42 | 0.5 (0.2–1.4) | 0.21 | 0.5 (0.2–1.2) | 0.12 |
Risk ratio and 95% CI were estimated using mixed effects log‐binomial model with hospital included as a random effect. Because ECPR is a rare event (0.8%), the odds ratio is an approximation to the risk ratio. We reported the unadjusted risk ratio (column 1), with the risk ratio adjusting for patient variables (age, sex, race, Hispanic origin, presenting rhythm status, subject type, and event location; column 2) and the risk ratio adjusting for patient and hospital variables (cardiac ICU beds, area type, teaching status, and admission period [2000–2004, 2005–2009, etc]; column 3). For the variables hospital beds, annual admission, and cardiac ICU beds/total beds (%), we did not adjust for cardiac ICU beds. CHF indicates congestive heart failure; CPC, cerebral performance category; CVA, cerebrovascular accident; ECPR, extracorporeal cardiopulmonary resuscitation; ICU, intensive care unit; and MI, myocardial infarction.
a
Unadjusted risk ratio.
b
Risk ratio adjusting for patient variables.
c
Risk ratio adjusting for patient and hospital variables.
d
CPC is defined as follows: CPC 1, good cerebral performance; CPC 2, moderate cerebral disability; CPC 3, severe cerebral disability; CPC 4, coma or vegetative state.