Doctoral Defense in Industrial Engineering - Ásgeir Örn Sigurpálsson

Doctoral candidate:
Ásgeir Örn Sigurpálsson

Title of thesis:
Pattern Scheduling: A practical approach to preventing surgery cancellations due to uncertainty in surgery times, bed availability and arrivals of semi-acute elective patients

Opponents:
Dr. Jaideep J Pandit, Professor at the University of Oxford, United Kingdom
Dr. Michael O'Sullivan, Associate Professor at the University of Auckland, New-Zealand

Advisors:
Dr. Rögnvaldur Jóhann Sæmundsson, Professor at the Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, University of Iceland
Dr. Tómas Philip Rúnarsson, Professor at the Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, University of Iceland

Other members of the doctoral committee:
Dr. Edmund Kieran Burke, Vice-Chancellor at Bangor University, Wales 

Chair of Ceremony:
Dr. Rúnar Unnþórsson, Professor and Head of the Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, University of Iceland

Abstract:
Demographic change, increasing cost of care, and shortage of hospital workers pose challenges in hospital management. As a response, hospitals maintain high utilisation of their existing resources by maximising patient throughput to minimise waiting times. However, maintaining a high resource utilisation on a continuous basis is likely to result in last-minute cancellations or rescheduling due to multiple sources of uncertainty. In this context, surgery scheduling has received central attention from researchers and healthcare officials globally. This research aims to increase our understanding of how to maintain a high throughput of elective patients under limited resources, while minimising the combined risk of last-minute cancellations and rescheduling. The objective is to build mathematical models that tackle the problem practically and precisely while considering several sources of uncertainty frequently resulting in last-minute cancellations and rescheduling. A single surgical speciality, General Surgery at Landspitali Hospital, was selected for the computational experiments, and the results were compared to the actual scheduling data. The results show that using chance constraints makes it possible to reduce the risk of last-minute cancellations due to uncertainty in surgery times and length of stay in a precise way. However, utilising such constraints makes the problem computationally intractable. Therefore, Pattern Scheduling is proposed to overcome the computational challenges by specifying practical rules. Further results show that leaving 20% of the weekly operating room capacity unreserved makes it possible to reduce the rescheduling required to accommodate unpredictable arrivals of patients with a high medical priority, while maintaining a high utilisation.

About the doctoral candidate:
Ásgeir Örn was born in 1990. He finished his B.Sc. in Industrial Engineering at the University of Iceland in 2014 and his M.Sc. in 2017. Ásgeir started his doctoral studies in Industrial Engineering in 2017. Alongside his doctoral studies, Ásgeir has taught several courses at the Faculty of Industrial Engineering, and now works as a specialist in risk management