Noninvasive Neuromonitoring of Hypothermic Circulatory Arrest in Aortic Surgery

Abstract

Background and Aims: Circulatory arrest carries a high risk of neurological damage, but modern monitoring methods lack reliability, and is susceptible to the generalized effects of both anesthesia and hypothermia. The objective of this prospective, explorative study was to research promising, reliable, and noninvasive methods of neuromonitoring, capable of predicting neurological outcome after hypothermic circulatory arrest. Materials and Methods: Thirty patients undergoing hypothermic circulatory arrest during surgery of the thoracic aorta were recruited in a single center and over the course of 4 years. Neuromonitoring was performed with a four-channel electroencephalogram montage and a near-infrared spectroscopy monitor. All data were tested off-line against primary neurological outcome, which was poor if the patient suffered a significant neurological complication (stroke, operative death). Results: A poor primary neurological outcome seen in 10 (33%) patients. A majority (63%) of the cases were emergency surgery, and thus, no neurological baseline evaluation was possible. The frontal hemispheric asymmetry of electroencephalogram, as measured by the brain symmetry index, predicted primary neurological outcome with a sensitivity of 79 (interquartile range; 62%–88%) and specificity of 71 (interquartile range; 61%–84%) during the first 6 h after end of circulatory arrest. Conclusion: The hemispheric asymmetry of frontal electroencephalogram is inherently resistant to generalized dampening effects and is predictive of primary neurological outcome. The brain symmetry index provides an easy-to-use, noninvasive neuromonitoring method for surgery of the thoracic aorta and postoperative intensive care.

Effect of combined use of cerebral oximetry and electroencephalogram monitoring on the incidence of perioperative neurocognitive disorders in adult cardiac and non-cardiac surgery: A systematic review of randomized and non-randomized trials

“…Table II shows the characteristics of the included studies. The included studies analyzed patients undergoing cardiac surgery (N = 7) 7,[16][17][18][19][20][21] , carotid surgery (N = 2) 22,23 , shoulder surgery in beach chair position (N = 3) [24][25][26] and other non-cardiac interventions (N = 3) 27,28 . Among the 15 included studies, two were retrospective 16,17 , eight were prospective 7,18,19,21,22,24,25,28 and five were a randomized controlled trial (RCT) 20,23,26,27,29 .…”

“…The included studies analyzed patients undergoing cardiac surgery (N = 7) 7,[16][17][18][19][20][21] , carotid surgery (N = 2) 22,23 , shoulder surgery in beach chair position (N = 3) [24][25][26] and other non-cardiac interventions (N = 3) 27,28 . Among the 15 included studies, two were retrospective 16,17 , eight were prospective 7,18,19,21,22,24,25,28 and five were a randomized controlled trial (RCT) 20,23,26,27,29 . However, the RCT by Meghawry et al 26 randomized the patients according to a hypotension induced protocol for shoulder surgery in beach chair position.…”

“…Stroke was the outcome of interest in 3 studies 17,19,22 . Interestingly, one retrospective study used the old nomenclature of neurological complications with focal injury, stupor or coma belonging to type 1 injury and deterioration in intellectual function, memory deficit or seizures belonging to type 2 injuries 17 .…”

“…In one study the authors analyzed bilateral raw EEG and the corresponding DSA provided by the NeuroSENSE ® DOA monitor 7 . In 4 studies the raw channel EEG was the used monitor 16,17,19,22 . Only 8 studies used an algorithm to avoid/treat cerebral oxygen desaturation and/or to treat EEG abnormalities, EEG suppression or abnormally low BIS values 7,16,17,20,23,25,27,29 .…”