Reliability of the Medtrac MDI Chronolog.
BACKGROUND
The Medtrac MDI Chronolog is an electronic device for monitoring adherence to metered-dose inhalers. It replaces previous models of the Nebulizer Chronolog and uses a different mechanism of recording actuations.


OBJECTIVE
This study was carried out to determine whether the new model can accurately record and report the date, time, and number of metered-dose inhaler actuations.


METHODS
Four canisters of beclomethasone (Beclovent) were discharged through four Chronologs with fresh batteries at a rate of 1, 2, 4, or 8 times twice daily for 7 days. Four additional canisters were used as controls and discharged simultaneously through the standard actuator. The weight of all canisters and Chronolog battery voltage were measured before and at the end of the 7-day experiment. The data retrieved from the Chronologs were compared with the information recorded manually during each discharge.


RESULTS
The loss in canister weight was consistent for the number of puffs discharged from all four Chronolog units and controls. However, the accuracy of the Chronologs in recording the number of actuations varied between 50% and 100%. The largest amount of data loss occurred with the unit used to discharge 8 puffs and was associated with a dead battery at the end of the 7-day trial. For actuations that were retrievable, the Chronologs accurately recorded the date and time.


CONCLUSIONS
Unexpected battery voltage drain and other mechanical problems that we encountered may cause data loss and the false appearance of missed doses. Thus the units that we tested were not sufficiently reliable to monitor patient adherence.
Brueckner
J W
JW
College of Pharmacy, Department of Pediatrics, University of Florida, Gainesville 32610-0486, USA.
Marshik
P
P
Sherman
J
J
Hendeles
L
L
D018927:Anti-Asthmatic Agents / Q000008:administration & dosage; D001507:Beclomethasone / Q000008:administration & dosage; D004334:Drug Administration Schedule; D016903:Drug Monitoring / Q000379:methods*; D006801:Humans; D009330:Nebulizers and Vaporizers; D010349:Patient Compliance; D012015:Reference Standards; D015203:Reproducibility of Results; D012984:Software
D018927:Anti-Asthmatic Agents; D001507:Beclomethasone