Continuous distribution widened the net — and stretched cold ischemia.
In March 2023 lung allocation moved to a continuous score (CAS), removing hard geographic boundaries. Transplants rose, but organs now travel farther: ischemic times and marginal-donor use have climbed sharply since.
Source: OPTN/UNOS STAR file, Dec 2025 release · lung/heart-lung transplants by transplant year. CAS/continuous distribution began March 2023.
5.8 → 8.9 h
Median cold-ischemia time jumped from 5.8 h (2022) to 8.9 h (2025), and the share of lungs implanted after >8 h rose from 17% to 57% — the footprint of broader, boundary-free sharing.
01 · Before & after
What changed from 2022 to 2025
+29%
Transplant volume (2,743 → 3,551)
8.9 h
Median ischemia (was 5.8 h)
57%
Lungs >8 h ischemia (was 17%)
19%
DCD donors used (was 7%)
02 · Cold ischemia
Organs travel farther under CAS
Median cold-ischemia time by transplant year. The inflection at 2023 tracks the move to continuous distribution.
Median ischemic time (hours)
CAS / continuous distribution began March 2023.
03 · Volume
More lungs transplanted
Annual lung/heart-lung transplant volume. Pre-CAS years muted; 2023–2025 highlighted.
Lung transplants per year
Broader sharing trades geography for time — more access, but longer ischemia and more marginal donors (see Ischemic Time vs Outcome and Donor Lung Utilization). Objective, fast offer-time assessment is more valuable as the pool widens and the clock lengthens.