Birgitta Versluijs

90 Discussion Discussion Our study in 142 pediatric patients shows that pulmonary screening before HCT with PFT, HRCT, and BAL is feasible. We could perform all the tests in the majority of pa- tients (86%). Abnormalities were found in 72% of patients. In 32% of patients, these abnormalities led to supportive/preemptive treatment according to guidelines. Only in patients with clinically significant chest HRCT, abnormalities a higher incidence of lung- injury was noted after HCT. Although not negligible, the costs seem justified in relation to the findings. It is well known that pulmonary function declines early after HCT, 9,10 and some studies have shown a continuous decline without reaching a plateau during prolonged follow- up. 9 Several studies have demonstrated that impaired PFT before transplantation in- creases the risk for post-transplantation lung complications and mortality. 1,9,11-14 Possible explanations for these observations are that patients can have such marginal lung reserve capacity, endangering a period of critical illness and/or further lung toxic events. Also, in patients with pre-existing lung injury, this organ may be at increased risk for allo- immune phenomena, such as graft-versus-host disease. We evaluated the yield of HRCT scanning. Omitting HRCT from our screening in this cohort would have missed 7 (5%) children with abnormalities, including 2 of the 4 with infiltrative lesions suspect for fungus. On the other hand, HRCT leads to radiation ex- posure and may require general anesthesia in children and, therefore, deserves critical appraisal. The relevance of abnormal findings on HRCT are a matter of debate. In the radiological reports in this study, abnormalities were described in 55% of patients. Be- cause the severity of the reported abnormalities varied considerably, we chose to take into account those HRCT findings which had “significant clinical meaning” at time of transplantation, such as consolidations requiring antibiotic or antifungal therapy, bron- chiectasis as a risk factor for infections warranting change in prophylaxis, or pleural ef- fusions requiring diuretics. In most patients, a plain chest x-ray was available but showed abnormalities in only 50%, and, of note, did not show any abnormalities in the 4 patients with signs of invasive fungal infection on HRCT (data not shown). The yield of BAL procedures was high in our study. Omitting BAL would have missed 19 (14%) patients with fungal colonization and 35 (25%) with RV. All these patients had normal HRCT scans and no significant pulmonary symptoms. 5