The effect of hypothermia during cardiopulmonary bypass on three electro-encephalographic indices assessing analgesia and hypnosis during anesthesia: consciousness index, nociception index, and bispectral index

Abstract

The depth of anesthesia is commonly assessed in clinical practice by the patient’s clinical signs. However, during cardiopulmonary bypass and hypothermia, common symptoms of nociception such as tachycardia, hypertension, sweating, or movement have low sensitivity and specificity in the description of the patient nociception and hypnosis, in particular, detecting nociceptive stimuli. Better monitoring of the depth of analgesia during hypothermia under cardiopulmonary bypass will avoid underdosage or overdosage of analgesia, especially opioids. Induced hypothermia has a multifactorial effect on the level of analgesia and hypnosis. Thermoregulatory processes appear essential for the activation of analgesic mechanisms, ranging from a physiological strong negative affiliation between nerve conduction velocity and temperature, until significant repercussions on the pharmacological dynamics of the analgesic drugs, the latter decreasing the clearance rate with a subsequent increase in the effect-site concentrations. Under the hypothesis that deep hypothermia induces massive effects on the analgesia and hypnosis levels of the patient, we studied whether hypothermia effects were mirrored by several neuromonitoring indices: two hypnosis indices, consciousness index and bispectral index, and a novel nociception index designed to evaluate the analgesic depth. In this clinical trial, 39 patients were monitored during general anesthesia with coronary atherosclerosis cardiopathy who were elective for on-pump coronary artery bypass graft surgery under hypothermia. The changes and correlation between the consciousness index, bispectral index, and nociception index with respect to the temperature were compared in different timepoints at basic state, during cardiopulmonary bypass and after cardiopulmonary bypass. While the three neuromonitoring indices showed significant correlations with respect to the temperature, the nociception index and consciousness index showed the strongest sensitivities, indicating that these two indices could be an important means of intraoperative neuromonitoring during induced hypothermia under cardiopulmonary bypass.

Analysis of the Clinical Effect of Music Combined with Hypnosis on Labor Analgesia Based on Data Mining

“…erefore, it is very important for the selection and training of Hypnotists. In addition, the degree of hypnosis is proportional to the maternal acceptance; it is impossible to have a strong maternal hypnosis, and it is impossible to hypnotize, so the maternal choice is also very critical [13].…”

Investigation of the Association between Bispectral index and Body Temperature during Abdominal Surgery; An Observational Study

“…In addition, hypothermia contributes a distinct decrease in cerebral metabolism and has an effect on the level of analgesia and hypnosis 14 . Due to decreased clearance of analgesics during hypothermia, the analgesic level increases providing a preferable analgesia 14 . Hypothermia provides significant decrease in cerebral metabolism, vasomotor responses, and quantitative EEG signals 5 .…”

“…Furthermore, a previous study presented that; the sevoflurane requirement increases with an increase in temperature 13 . In addition, hypothermia contributes a distinct decrease in cerebral metabolism and has an effect on the level of analgesia and hypnosis 14 . Due to decreased clearance of analgesics during hypothermia, the analgesic level increases providing a preferable analgesia 14 .…”

Neuromonitoring and Neurocognitive Outcomes in Cardiac Surgery: A Narrative Review

“…[170][171][172] Nevertheless, pEEG-guided anesthesia still may prove appealing to clinicians, with other objective clinical signs being unreliable during CPB. 173 Aside from specifically guiding depth of anesthesia, pEEG devices can be used to detect cortical burst suppression, which is associated with POD in cardiac surgery patients. 136 Prior to the onset of burst suppression in CPB patients, there markedly decreased alpha-and beta-wave power, which could potentially be used as a marker for susceptibility for burst suppression and hence POD, and, thus, denotes a point at which to intervene.…”