Is Low Melatonin Linked to Postoperative Delirium?

A new study out of Japan suggests that patients in the ICU with postoperative delirium have lower melatonin levels in the hour following surgery than those who did not experience the same complication. The pain caused by a surgical incision may contribute to the risk of postoperative cognitive dysfunction. Sometimes transient impairment in learning and memory occurs that affects a small, but significant number of patients in the days following a surgical procedure.

A second study out of Massachusetts General Hospital (an animal study), also recognized that there exists a probable mechanism for pain-induced cognitive impairment, suggesting pathways that may be targeted by potential preventive measures. What do these findings mean?

According to Zhongcong Xie, MD, PhD, director of the Geriatric Anesthesia Unit in the Massachusetts General Hospital, the findings suggest that pain is the preoperative factor that contributes to the risk of cognitive dysfunction in surgical patients. He goes on to state that “While postoperative cognitive dysfunction may be temporary, it still can have a major impact on the quality of life of patients and their caregivers at a time when patients’ ability to participate in their own care is very important.”