 |
 |
Dear All I'm writing to ask if any of you have ever been asked to make the necessary electrical connections to enable a ventilator to be powered from a wheelchair's +24V batteries. Here in Lothian, we have been asked to do this work for three patients over the last year. All of these patients use Breas Medical ventilators that have a +24V connection to enable the connection of an external battery pack. The result of the work is that the ventilator can be mounted on the rear of the powered wheelchair, on a specially manufactured tray, without the need for an external battery pack to be fitted to the wheelchair. Powering the ventilator from the wheelchair batteries reduces the amount of hardware that has to be fitted to the powered wheelchair and it enables the external battery pack to be kept as a reserve supply for emergencies. Recently the department in Lothian that provide the ventilators to patients has informed me that they don't know of any other centres that are providing these electrical connections and indeed they know that some refuse to do it. This surprises me because it seems logical to carry out this work. Initially I contacted Braes and I was informed that there would be no particular problem in making this connection. My risk analysis indicated that we could only proceed with this work if the ventilator had an internal battery supply that it would switch to automatically in the event of a failure in the wheelchair electrical supply. The internal battery pack provides approx. 1 hour of ventilation which is more than enough time to connect either the external battery or a mains supply. My questions are, have any of you been asked to do this type of work and if so have you agreed or refused and what are the reasons behind your decision? On a related issue, we have also powered communication aids from the powered wheelchair batteries. I have concerns about generating mains type voltages on wheelchairs. I've therefore avoided using handy mains voltage converters and I've included dc/dc regulators to convert from the wheelchairs +24V to the required dc voltage. Do any of you have views on the use of Handy Mains converters on powered wheelchairs? Colin Geggie Clinical Bioengineer Rehabilitation Engineering Services Eastern General Hospital Seafield Road Edinburgh EH6 7LN Tel. 0131 536 4695 Fax. 0131 536 4840