Respiratory
Division
Diagnostic Products
Spirometry
Spirometry made Simple
F.A.Q.
What precautions are there against cross-contamination by infection of the instruments ?
There is a one-way valve in the VM1 and VM PLUS which prevents the patient from inhaling through the device, thus minimiosing the risk of cross-contamination. Disposable mouthpieces are available for every new patient, and the standard plastic mouthpiece is sterilisable. The mechanical sections of the device are easily disassembled for cleaning and disinfection.
How can one tell when the spirometer needs to be re-calibrated ?
There should be no more than 10% variation between the PEF readings shown on the digital display and the mechanical scale. If a greater difference develops, then the device should be cleaned. If it continues to read incorrectly, re calibration by experienced technicians is required (in the UK, Clement Clarke – free for the first 12 months, thereafter £25 plus P&P).
I have been using my VM1 for a period of time and recently the word “bAd” sometimes appears in the digital display – why ?
The error-sensing software in the VM1 and VM PLUS has been developed to act as a trouble-shooter and there are two reasons why this message appears. Firstly, the software detects poor spirometry technique, such as when patients “cough” or “peashoot” into the mouthpiece. Secondly, as with all Spirometers, dirt and moisture from patients’ breath can affect the machines accuracy. The machine will need to be cleaned to restore its sensitivity.
I have been told that readings must always be in BTPS and not in ATPS – what does this mean ?
BTPS means Body Temperature and Pressure Saturated (with water) and ATPS means Ambient Temperature and Pressure Saturated ( with water). Air inside the lungs (BTPS) has a higher volume than in the atmosphere (ATPS) because air expands when warmed. For example, 3 litres of air at room temperature occupies 3.25 litres at body temperature. Both the VM1 and the VM PLUS automatically produce readings converted to BTPS which is preferable for clinical use.
How long does a battery last ?
Generally, three to six months depending on how frequently the instrument is used. A battery-low warning arrow will indicate when a change is required. The VM PLUS has an additional long-life battery (10 years) to maintain the clock and any data stored in the memory.
