Correlation of Cerebral Oxygen Saturation Measured From 2 Sensor Sites: Forehead vs. Temporal

Cardiac surgery and neurosurgery may decrease cerebral blood flow leading to neurologic morbidity, e.g., postoperative stroke, delirium, or postoperative cognitive dysfunction. Regional cerebral oxygen saturation (rScO2) monitor via Near-infrared spectometry (NIRS) is thus recommended for early detection and correction. Murkin et al.(2007) conducted a randomized controlled trial in coronary artery bypass graft (CABG) with NIRS monitoring showed that patients who received intervention to avoid rScO2 < 75% of baseline had less major organ morbidity including stroke, and mortality. Senanayake et al.(2012) revealed that NIRS could decrease neurologic complication in patients undergoing ascending aortic replacement with moderate hypothermic circulatory arrest.

The standard site of NIRS sensor is forehead area. There are some types of surgery involving incision at forehead area which makes it not possible to attach sensor at this site. The investigators propose an alternative sensor site at temporal area to be used in such situation.

The objective of this study is to assess the correlation of rScO2 measured from sensor attached at forehead vs. temporal area.

Inclusion criteria

• age =/> 18 y
• undergoing elective cardiac surgery
• American Society of Anesthesiologists (ASA) classification II-III

Exclusion criteria

• history of intracranial or carotid vascular disease
• previous surgery at face or brain
• abnormal anatomy of face
• re-do surgery