Unsupervised home spirometry is not equivalent to supervised clinic spirometry in children and young people with cystic fibrosis: Results from the CLIMB-CF study.

BACKGROUND: Handheld spirometry allows monitoring of lung function at home, of particular importance during the COVID-19 pandemic. Pediatric studies are unclear on whether values are interchangeable with traditional, clinic-based spirometry. We aimed to assess differences between contemporaneous, home (unsupervised) and clinic (supervised) spirometry and the variability of the former. The accuracy of the commercially available spirometer used in the study was also tested. METHODS: Data from participants in the Clinical Monitoring and Biomarkers to stratify severity and predict outcomes in children with cystic fibrosisc (CLIMB-CF) Study aged ≥ 6 years who had paired (±1 day) clinic and home forced expiratory volume in 1 s (FEV1 ) readings were analyzed. Variability during clinical stability over 6-months was assessed. Four devices from Vitalograph were tested using 1 and 3 L calibration syringes. RESULTS: Sixty-seven participants (median [interquartile range] age 10.7 [7.6-13.9] years) provided home and clinic FEV1 data pairs. The mean (SD) FEV1 % bias was 6.5% [±8.2%]) with wide limits of agreement (-9.6% to +22.7%); 76.2% of participants recorded lower results at home. Coefficient of variation of home FEV1 % during stable periods was 9.9%. Data from the testing of the handheld device used in CLIMB-CF showed a potential underread. CONCLUSION: In children and adolescents, home spirometry using hand-held equipment cannot be used interchangeably with clinic spirometry. Home spirometry is moderately variable during clinical stability. New handheld devices underread, particularly at lower volumes of potential clinical significance for smaller patients; this suggests that supervision does not account fully for the discrepancy. Opportunities should be taken to obtain dual device measurements in clinic, so that trend data from home can be utilized more accurately.

Seat belt associated central line fracture--a previously unreported complication in cystic fibrosis.

Totally implantable venous access devices (TIVAD) are used widely in the management of cystic fibrosis (CF) [Standards of Care: Standards for the clinical care of children and adults with cystic fibrosis in the UK. The Cystic Fibrosis Trust's Clinical Standards and Accreditation Group. Cystic Fibrosis Trust, London, UK, 2001]. They have been shown to be safe and advantageous in the long term administration of intravenous antibiotics [A-Rahman A, Spencer D. Totally implantable vascular access devices for cystic fibrosis. Cochrane Database Syst Rev 2003(3)]. However, TIVADs are not without short and long term complications including infections, thrombosis and mechanical failure [Munck A, Malbezin S, Bloch J. Follow up of 452 totally implantable vascular devices in cystic fibrosis patients. Eur Respir J 2004;23:430-4; Aitkin ML, Tonelli ML. Complications of indwelling catheters in cystic fibrosis: a 10-year review. Chest 2000;118:1598-602; Deerojanawong J, Sawyer SM, Fink AM, Stokes KB, Robertson CF. Totally implantable venous access devices in children with cystic fibrosis. Thorax 1998;53:285-89; Rodgers HC, Liddle K, Nixon SJ, Innes JA, Greening AP. Totally implantable venous access devices in cystic fibrosis: complications and patients' opinions. Eur Respir J 1998;12:217-20; Yung B, Campbell IA, Elborn JS, Harvey JS, Shale DJ. Totally implantable venous access devices in adult patients with cystic fibrosis. Respir Med 1996;90:353-56; Kariyawasam HH, Pepper JR, Hodson ME, Geddes DM. Experience of totally implantable venous access devices (TIV Ads) in adults with cystic fibrosis over a 13-year period. Respir Med 2000;94:1161-5]. Patients should be counselled prior to TIVAD insertion regarding the risks and instructed on post-operative care of the device to minimise the risks. However it is not routine practice to advise on seating position within the car in relationship to the seatbelt placement over the anterior chest wall. Line failure due to direct pressure from a seatbelt worn to prevent injury in the sudden deceleration involved during a motor vehicle accident (MVA) has not been described previously in the CF literature We report the case of an 8 year old child who fractured her Vascuport(R) line secondary to seatbelt trauma following a road traffic accident (RTA). Children and adults with CF should be advised to sit in the car on the side that places the shoulder strap of the seatbelt on the opposite side to the TIVAD line.