Waiting times for outpatient clinics are a useful measure of the performance of pathways between primary and acute care. The challenge is to design services that reliably achieve zero waits. There are two causes of waits: queues to manage demand, and a lack of resources.

Waiting times for outpatient clinics are a useful measure of the performance of pathways between primary and acute care. The challenge is to design services that reliably achieve zero waits. There are two causes of waits: queues to manage demand, and a lack of resources.

The way to achieve zero waits is to design systems around patients rather than the organisation, but patients are variable and organisations have fixed financial constraints. Designing a patient-centred outpatient system that is affordable and guaranteed to work is difficult - but not impossible.

Over two years, the vascular surgery outpatient clinic at Good Hope Hospital trust in Sutton Coldfield was redesigned using methods from outside healthcare. The principle was to eliminate all steps that took time but did not add value.

The first step was to change the conventional multi-visit, new-review clinic model to a one-stop clinic where patients could get assessment, tests and treatment in one visit, typically eliminating 12 weeks of unnecessary waiting at no additional cost.

The second was to eradicate delays caused by paper-based communication with a shared electronic patient record for the most complex problem ? chronic wounds ? that placed heavy demands on vascular outpatient services.

The one-stop booking process was redesigned to eliminate waiting within the clinic as far as possible. The result was a 40 per cent increase in maximum capacity, which also provided flexibility to meet variation in patient demand and eliminated the need for a waiting list.

Designing a booking process that was guaranteed to work before it was implemented presented a challenge. I used a computer science technique called discrete event simulation to build a model which I then used to test a wide range of booking strategies.

The best strategy was identified by looking for the shortest waiting time with the resources of staff, equipment and facilities and demand. The best design was implemented as a simple paper-based booking template and has been successfully in use for over a year.

Simon Dodds is consultant vascular surgeon at Good Hope Hospital trust