The customer reported oxygen (o2)/carbon dioxide (co2) and diffuse lung carbon monoxide (dlco) calibrations failed while in use involving the vmax encore 22 pulmonary function analysis instrument.The customer stated the device was utilized on a patient for pulmonary function testing (pft) at the time of the event, and the patient's test results were released to the physician.The physician then noted the results were lower than predicted and believed chemotherapy was the cause of the patient's low pft results.Consequently, the physician stopped the patient's chemotherapy treatment.The customer has not informed the physician of the patient's false results and stated that the physician will not be informed.The customer stated that there has been no report of patient consequence and that the patient is currently under surveillance.The customer also noted diffusion was low at the time of the event.The customer stated no further patient status/information will be retrieved from the physician.The customer ordered a new vmax encore 22 instrument and placed it in operation.No additional information has been provided by the customer at present.The suspect device has been returned to carefusion for analysis.
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Failure analysis of the returned material: visual examination of the vmax module as received revealed no anomalies and or physical damage.Electrical check/room air measures displayed a normal pbar of 7.501 vdc; pbar room air at 6.195 vdc; o2 sensot at 6.112 vdc; and co2 at 1.795 vdc.Verification testing followed by connecting the gas supply hoses to the rear of the unit, in which the gases were adjusted as follows: diffuse lung carbon monoxide (dlco) 80 psi, o2 = 60 psi, cal1 = 60 psi, cal2 = 60 psi, the unit was powered and allowed to warm-up for 30 minutes.Afterwards, diagnostics displayed room air measures pbar at 6.195 vdc; co2 at 1.795 vdc; and o2 at 6.112 vdc.Several calibrations were performed.The first calibration failed; however, the second calibration passed (no adjustments were made to the vmax module).After 20 minutes, multiple calibrations were performed which were very unstable; calibration passed and at times, failed.In addition, the cover was removed to check for internal damages; all connections to and from the unit were intact and fully inserted.The customer¿s reported issue was able to be duplicated.In conclusion, the likely cause of the event is attributed to the co2 analyzer.A definitive root cause is unknown.Carefusion continues to track and trend any incident related to this issue.
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