Do cell phones cause an interference with medical equipment?

Depends on the age of the equipment, people in hospital would be surprised how old a lot of the equipment can be - some of it can be more than 15 years old; this type of equipment is more liable to interference as it wasn't a major concern when it was originally manufactured, newer more modern equipment won't be as susceptible as manufacturers are all too aware of the consequences.

There are many other factors some of which are:

* The power output of the transmitting device * How close the device is to the equipment * What the purpose of the equipment is (eg, an ecg machine deals with very low level signals and therefore would definitely be more susceptible than say a non-invasive blood pressure machine)