Transient decrease of cerebral oxygen saturation during the emergence in children

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. CC Lee et al. [1] had reported that regional cerebral oxygen saturation (rSO 2) decreases neither with an episode of arterial desaturation nor overt hemodynamic compromises during emergence in children. Following their study the authors suggested that the decrease of rSO 2 may correlate inversely with the fraction of anesthetic concentration (F E) and the duration of anesthesia, and positively with the use of sevoflurane. This is the first report published on the change of cerebral oxygen saturation during the emergence of pediatric anesthesia. Although brain is the primary target of general anesthetics, it is still the least monitored organ during general anesthesia. Anesthesia is usually managed by using indirect parameters of adequate brain oxygenation because central nervous system (CNS) monitoring is technically difficult and demanding. Furthermore, most CNS monitors are designed to monitor cerebral hemodynamics or electrical activity, including the measurement of intracranial pressure and cerebral blood flow and electroencephalography. Despite the existence of some invasive monitoring systems measuring brain oxygenation, the monitor cannot be performed routinely for all anesthetized patients because of its severe complications. In some surgical field, cardiovascular-and neurosurgery, postoperative neurological complication remains an important cause of increasing morbidity and mortality. Neurologic complications in the anesthetized patient can be followed by a devastating result for the patient and their family. Therefore, monitoring and prevention of neurologic complication are important. Ferrari et al. [2] reported the studies about first human cerebral oximetry, using near-infrared spectroscopy (NIRS) in 1985. Technology of NIRS has developed to allow continuous, non-invasive, and bedside monitoring of rSO 2 by providing information on the balance between brain oxygen supply and demand. Cerebral perfusion is a major factor for regional and global imbalance in oxygen supply and demand, which may result in brain injury. Similar to pulse oximetry, cerebral oximetry is the method to monitor regional cerebral perfusion. While pulse oximeter measures oxygen saturation of hemoglobin in arterial blood, cerebral oximeter measures oxygen saturation in the brain tissue, arterial, and venous blood. Since the ratio of arterial and venous blood is about 15 : 85, NIRS primarily measures cerebral venous saturation, which reflects the oxygen balance in the brain. Several studies reported normative rSO 2 ranges from 55 …