International Journal of Pediatric Otorhinolaryngology 137 (2020) 110242 Available online 11 July 2020 0165-5876/© 2020 Elsevier B.V. All rights reserved. Decreased cerebral oxygen saturation levels during direct laryngoscopy with spontaneous ventilation in children Oshri Wasserzug a, c, * , Gadi Fishman a, c , Ophir Handzel b, c , Daniel Stockie c , Yael Oestreicher-Kedem b, c , Dan M. Fliss b, c , Ari DeRowe a, c a Pediatric ENT Unit, Tel Aviv, Israel b Department of Otolaryngology, Head & Neck and Maxillofacial Surgery, “Dana” Children’s Hospital, Tel Aviv, Israel c Department of Anesthesiology, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel A R T I C L E INFO Keywords: Spontaneous ventilation Children Laryngoscopy Oxygenation Saturation level ABSTRACT Introduction: Direct laryngoscopy in children is usually performed with spontaneous ventilation and monitored by pulse oximetry. It is currently unknown if spontaneous ventilation has an effect on cerebral oxygenation. We hypothesized that cerebral oxygenation may be impeded during direct laryngoscopy with spontaneous ventila- tion in children. Objective: Our objective was to determine if children who undergo direct laryngoscopy under general anesthesia with spontaneous breathing experience signifcant reductions in cerebral oxygen saturation levels, and whether or not these reductions are accompanied by decreases in peripheral oxygen saturation levels. Methods: This pilot study included 16 consecutive children who underwent direct laryngoscopy under general anesthesia and spontaneous ventilation. The INVOS™ system, which is currently used to monitor cerebral oxygen saturation levels during neurosurgery and cardiothoracic surgery, consists of a processing unit and 2 sensors that are applied to the patient’s forehead. We used it to record cerebral oxygenation levels throughout the procedure. Peripheral pulse oximetry was recorded simultaneously, and the results were compared to the levels recorded by the INVOS™ system. Results: Cerebral oxygen saturation levels decreased by more than 20% from baseline in 7/10 children with tracheostomy and in 2/6 children without tracheostomy, while peripheral oxygen saturation levels remained intact in all the children. The mean time from induction of anesthesia to signifcant decrease in the cerebral oxygenation level (rSO2) was 14 � 6 min for the tracheostomy group and 14.5 � 1.5 min for the no tracheostomy group. Conclusions: Children who undergo direct laryngoscopy under general anesthesia with spontaneous ventilation may display reductions in brain oxygenation levels that are not detected by standard pulse oximetry, which refects only peripheral oxygenation levels. Further study is required to explore the possible effect of this phe- nomenon in children who undergo direct laryngoscopy. 1. Background Measurement of the regional cerebral oxygenation (rSO2) level has been widely used in children who undergo cardiac [1–3] and vascular surgery [4,5]. It serves to detect early signs of low brain oxygenation when the peripheral pulse oximeter still displays oxygenation levels within normal limits [5]. Several studies demonstrated prolonged cognitive impairments after these surgeries due to low brain oxygenation levels that occurred intraoperatively [2,3,6]. As a result, once a critical low oxygenation level has been reached, the procedure is halted for a period of time in order to enable the brain tissue to recover [7]. In parallel, it has become evident that the mode of anesthesia can signifcantly affect cerebral oxygenation [5,8–10]. Direct laryngoscopy in children is usually performed under spontaneous ventilation. The anesthesiologist is faced with a real challenge when applying this unique mode of ventilation: on the one hand, the child must be kept at a level of * Corresponding author. Pediatric ENT Unit, Department of Otolaryngology, Head & Neck and Maxillofacial Surgery, "Dana" Children’s Hospital, Tel Aviv Sourasky Medical Center, 6 Weizman Street, Tel Aviv, 6423906, Israel. E-mail address: droshriw@gmail.com (O. Wasserzug). Contents lists available at ScienceDirect International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl https://doi.org/10.1016/j.ijporl.2020.110242 Received 27 February 2020; Received in revised form 1 July 2020; Accepted 1 July 2020