Pulmonary complications are a major cause of morbidity and mortality following allogeneic/matched unrelated hematopoietic stem cell transplant (HSCT). Respiratory muscle weakness may contribute to pulmonary morbidity in subjects who develop pulmonary complications or graft versus host disease (GVHD) following HSCT. We routinely test inspiratory (PI) and expiratory (PE) respiratory muscle strength in all HSCT subjects who are having pulmonary function testing (PFT) and the purpose of this study was to analyze these data.
We combined the databases in the pulmonary function laboratory and in the HSCT and identified 46 subjects who underwent full PFT and the additional PI and PE measurements following allogeneic/matched unrelated HSCT between 1999 and 2003. The data were de-identified, entered into an Excel spreadsheet and analyzed using SAS. This study was approved by the Human Investigation Review Committee.
The distribution of values obtained for PI, PE and maximal voluntary ventilation (MVV) were as follows(A=values <60% predicted, B= 60-79% predicted, C= >79% predicted). PI: 9 (19.57%)(A), 15 (32%)(B), 22 ( 47%)(C); PE:33 (71%)(A),7 (15%)(B),6 (13%)(C); MVV:12 (26%)(A),13 (28%)(B),21 (45%)(C). We then compared patients with PI < 59% predicted (n=9) with those with PI ≥60% predicted (n=37) to better define the clinical relevance of a moderate reduction in muscle function. Patients with PI<59% predicted had significantly lower values ( p < 0.05) for FVC, MVV, PE and Dlco. There was no significant difference between groups for age, body mass index, time elapsed from HSCT to PFT and FEV1. GVHD was present in 58% of all patients, with no difference in incidence between these two PI groups.
Conclusion: Respiratory muscle weakness is present in a significant percentage of patients undergoing PFT testing following HSCT. These findings may help identify patients at increased risk of increased pulmonary morbidity in the post HSCT period. (Supported by HL: 04411-02).
Respiratory muscle weakness may contribute to pulmonary morbidity following HSCT. Chronic GVHD may be a risk factor for respiratory muscle weakness in this population.
A.C. White, None.