Challenges in Perioperative Cerebral Oximetry Monitoring: A Case of Clofazimine-Induced Skin Pigmentation Interference.

Perioperative stroke is a potentially devastating complication in patients undergoing noncardiac surgery. The most consistent risk factor associated with the condition is a history of a prior stroke. Cerebral oximetry is a simple, non-invasive, and continuous monitoring device that uses near-infrared spectroscopy (NIRS) to monitor cerebral oxygenation. However, like other monitoring devices, cerebral oximetry has certain limitations, and it must be interpreted cautiously and by taking into account all available clinical information related to the patient. We present a case of a 62-year-old Caucasian woman with a past medical history of a transient ischemic attack (TIA), who had been advised to undergo a right pneumectomy by video-assisted thoracoscopic surgery for treating chronic infection of bronchiectasis. Before administering any drug and while the patient was still alert, we monitored NIRS, and the values recorded were 15 on the left side and 26 on the right side. Despite being Caucasian, she had a darker brownish skin color due to chronic clofazimine use, which is known to cause skin pigmentation. Skin pigmentation is known to attenuate the transmission of near-infrared (NIR) light, potentially affecting the estimation of cerebral oxygen saturation. Thus, our patient suffered from clofazimine-induced skin pigmentation, which may have interfered with the NIR light transmission, which explains the extremely low values observed. Regional intracerebral oxygen saturation should be interpreted in the context of all available clinical information since NIRS transmission can be influenced by several factors and skin pigment has been found to independently influence regional intracerebral oxygen saturation. Apart from race or high serum bilirubin concentration, we should also consider other causes of skin pigmentation alterations, such as pharmacological therapy.