New telemetric system for daily pulmonary function surveillance of lung transplant recipients

Background. Following lung transplantation, prompt diagnosis and therapy of acute pulmonary rejection and infection episodes relies primarily upon cha nges in pulmonary function and determines long-term outcome. We tested a ne w system that allows daily monitoring of the patient's pulmonary status eve n after discharge from the hospital. Methods. Seven lung transplant recipients from our center were equipped wit h a telemetric monitoring device consisting of a portable flowmeter and a s pecial modem unit. The flowmeter measures forced vital capacity (FVC), forc ed expiratory volume per second (FEV,), and mid expiratory flows (MEFs), en codes information like fever, cough, and dyspnea in a binary code form, and stores all values in a 32 kB memory unit. After its use, the patient posit ions the flowmeter onto the modem unit which automatically connects to a ce ntral computer at our center to transfer all saved data. The whole set can be used via any regular phone jack. The patient's file in the computer can be checked every day. Results. All patients learned to use the unit during their postoperative st ay or during later follow-up, and were able to apply the system at home. In a mean follow-up period of 10.3 +/- 2.2 months, 15 episodes of significant deterioration in home pulmonary function tests (PFTs) (>10%) were register ed in 6 patients, which were all confirmed by in-hospital body plethysmogra phy. They resulted in diagnoses of 4 episodes of acute rejection, 6 cases o f beginning bacterial pneumonia, and 5 cases of, most likely, viral tracheo bronchitis. Only 1 patient had to be admitted to the hospital. All patients PFTs returned to previous values after treatment. Conclusions. Telemetric monitoring of graft function in lung transplant rec ipients allows reliable early diagnosis and treatment of infection or rejec tion, which might help to prevent exacerbation of the pathology and reduce quantity of amounting graft dysfunction. (C) 1999 by The Society of Thoraci c Surgeons.