Information received a smiths medical tracheostomy|pvc - portex tubes blue line ultra (blu) would not hold pressure.The customer confirmed in a pre-use check that the product worked properly.He then started to use it with 30 mmhg of air pressure applied to its cuff.However, in 30 minutes or so, the pressure decreased to 7-10 mmhg.As this event was repeatedly observed, he changed the product to another one in one (1) day after starting to use the first one.No patient injury.