Telemetric monitoring of pulmonary function after allogeneic hematopoietic stem cell transplantation

Background. Late-onset noninfectious pulmonary complications (LONIPC) are both frequent and severe after allogeneic hematopoietic stem cell transplantation (HSCT). The high mortality rate (40-80%) may be related to delayed diagnosis. We assessed the use of telemetric home surveillance of pulmonary function for early diagnosis of LONIPC in transplant recipients. Methods. This prospective study monitored pulmonary function in 37 allogeneic HSCT recipients. About 3 months after HSCT, they received a portable spirometer that measured forced vital capacity, forced expiratory volume per second, and midexpiratory flow 25-75 (MEF25-75). Data were transmitted twice weekly by telephone. Conventional plethysmography confirmed any significant deterioration (> 20%). Results. Thirteen episodes of spirometric deterioration were detected by telemetry in 11 patients during a median 17-month (4-41) follow-up period after transplantation. In these cases, examinations including spirometry, high-resolution thoracic computed tomography and bronchoalveolar lavage diagnosed LONIPC in eight episodes in seven patients (cumulative incidence 23.4%, SE 0.08, at month 24 after transplant): bronchiolitis obliterans (130, n=3), interstitial pneumonia (IP, n=4), or both BO and IP (n=1). Five episodes improved and three were stabilized with increased immunosuppressive therapy. At the last follow-up, of the seven patients with LONIPC, one successfully stopped immunosuppressive therapy, two were receiving low-dose mycophenolate mofetil, and four were receiving low-dose corticosteroid therapy. There were no cases of respiratory failure and no patient died from LONIPC. Conclusion. Telemetric home monitoring of pulmonary function is a useful procedure for early diagnosis of LONIPC before clinical pulmonary symptoms and may improve outcome after allogeneic HSCT.