An international team of scientists, including researchers from the University of Granada, find that the speed of saccadic movements is an excellent way to objectively measure the level of fatigue in a physician.

Their study results show that after a 24-hour medical shift, the speed of saccadic movements (rapid eye movements) diminishes and the subjective perception of fatigue augments. However, the execution of simulated laparoscopic tests is not affected by this type of fatigue, the researchers found.

This research reveals that the speed of saccadic movement is an excellent index to measure objectively the level of fatigue in the medical profession. In an article published in Annals of Surgery, scientists evaluated the performance of doctors from the Traumatology Service at St Joseph’s Hospital and Medical Centre, Phoenix, before and after their call-day (a 24-hour shift during which doctors do not get any sleep). All the call-day doctors had the speed of their saccadic eye movements measured before and after the shift. Besides, they had to perform simulated laparoscopic tests (also before and after this 24-hour shift).

Subjective Fatigue Perception

Results showed that after long hours, the speed of saccadic movements diminished, while their subjective perception of fatigue increased. However, in the simulated laparoscopic tests after the shift, the execution was not affected in any significant way by their fatigue.

This means that—fortunately for patients—the previous work hours did not have a negative impact on their surgery practice. This supports the hypothesis that fatigue is not the only source of errors in medical professionals. There is a complex relationship between continuous care, patient safety, economic factors, and the level of fatigue in doctors themselves.

“It is also true that those other professional competence resources can do little when there is an excess of working hours, and consequently those results are fundamental to contribute to the regulation of shifts and schedules, based on objective data on fatigue and performance,” says Leandro Luigi Di Stasi, Fulbright researcher at the Barrow Neurological Institute (Phoenix), and Andrés Catena, director of the Centre for Research on Mind, Brain and Behaviour at the University of Granada, in a release.

Avoiding Errors

In Spain, around 10% of hospitalized patients suffer some type of adverse episode as a result of medical attention, and about 50% of these errors could have been avoided by the application of safer clinical practices.

“For these reasons, all those strategies whose objective is to know the factors that lead to unsafe medical practices, and consequently diminish patient safety, are part of the agenda of several international organizations, including the World Health Organization,” according to Di Stasi and Catena.

Since long work shifts and overtime hours are both becoming more frequent, especially among resident doctors, “the study of fatigue as a factor that contributes to the prevention of errors in the health system has become one of the main topics in risk management within this context.”

The results of this research also open to debate the number of hours that doctors can work without affecting patient safety. For instance, in the United States residents work almost twice as their Spanish or French counterparts (80 hours a week versus 40).

The authors say the results of this study can also be applied to other fields similar to medicine, which also require long hours involving large amounts of sophisticated knowledge and complex decision-making skills coupled with technical complexity—such as civil and military aviation.