NZ researchers seek to improve IV infusion

Software glitches and issues about the usability of high-tech infusion pumps have raised questions about device safety, according to researchers in New Zealand's University of Waikato.

“Hospitals don’t let the manuals for these devices get anywhere near their staff,” says Dr Judy Bowen, an expert on the design of safety-critical interactive systems in the Department of Computer Science at the University of Waikato. “The Waikato District Health Board (DHB) develops some of its own training materials and uses those developed by pump distributors – and when you look at how these devices work, you can understand why.”

Dr Bowen and Professor Steve Reeves of the Formal Methods Group are working the DHB Biomedical Division at Waikato Hospital in order to “reverse engineer” some of the pumps used in the hospital. Dr Bowen’s focus is on the user interface, using mathematical modelling in the instructions manual and observing divergences with the device’s actual behaviour.

“We’ve found some interesting and unexpected behaviours,” Bowen says. “For example, when you hit the on/off button during set-up, the pump reverts to its initial settings, so the operator would then need to reset the infusion rate, volume and time. But there’s nothing in the manual to warn you about this.”

Dr Bowen says that the problem lies in the process typically used in software development. According to her, a solution may be found in mathematical modelling, where formal models may be used to derive the manual to guarantee a match.

Formal software modelling is already being used in safety-critical areas such as aerospace, networks, mass transit systems and car manufacturing. Professor Reeves says there’s no reason why it can’t be applied to the relatively young medical device industry.

“With formal modelling, we can guarantee that the device will do exactly what it’s meant to do,” says Professor Reeves. “There are none of the bugs you inevitably get with conventional software development because you can use the model to generate exhaustive tests. We’ve got the means to add failsafe software to these small, high-value devices, which could open the door to a lucrative niche export industry for New Zealand.”

Back at Waikato Hospital, the researchers are now using their initial findings to advice on where and how the devices can be safely used.