The International Society for Heart and Lung Transplantation (ISHLT) defined criteria in 1993 for the bronchiolitis obliterans syndrome (BOS, obliterative bronchiolitis).
Parameters:
(1) current FEV1
(2) baseline FEV1
(3) histopathologic evidence of obliterative bronchiolitis
FEV1 as percent of baseline =
= (current FEV1) / (baseline FEV1) * 100%
FEV1 as Percent of Baseline
BOS Severity
Stage
> 80%
none or not significant
0
66 - 80%
mild
1
51 - 65%
moderate
2
< 50%
severe
3
where:
• The specifications for Stage 0 was an FEV1 "80% or more" and for Stage "66-80%", with overlap at 80%. Subsequent references indicate 80% is Stage 1.
Histopathologic Evidence of Obliterative Bronchiolitis
Subcode
absent
a
present
b
To read more or access our algorithms and calculators, please log in or register.
