Near-infrared Spectroscopy (NIRS) in Vascular Surgery 

REC REF:  18/LO/0270

Active and recruiting.

This is prospective observational study to evaluate the ability of near Infra-Red Spectroscopy (NIRS) to predict and/or diagnose low blood flow due to arterial hypotension, surgical injury to spinal arteries, or embolic events, which are often suspected after the anaesthetic effects have become less strong.


  • To determine the regional tissue oxygenation of paraspinal muscles of patients undergoing thoraco-abdominal aortic aneurysm (TAAA) surgery and how changes in the oxygen levels in mascle tissues correlate with the incidence of post-operative paraplegia or paralysis.
  • To determine the cerebral oxygenation of patients undergoing vascular surgery and how changes in this correlate with post-operative morbidity and mortality


All surgeries and anaesthetics have the potential to cause post-operative complications. They can increase the length of hospital stays and result in longer recovery times. Anaesthetic and surgical techniques have evolved over the years to reduce the incidence of post-operative complications, such as post-operative confusion; however, an accurate and reliable method to predict and thus prevent them from occurring is still lacking.
NIRS is a non-invasive method that can be used to determine the oxygenation level of tissue. Using the absorption ratio of red and infra-red light by haemoglobin found in red blood cells, NIRS can be used to measure regional oxygen saturation.
In this study, we are exploring the use of NIRS to monitor blood flow to the spinal cord during complex surgery of the thoracic aorta and eventually devise strategies to prevent low blood oxygen levels in the muscles from occurring.