Sniffin' odors in the aging population? Smells like a new way to predict postoperative outcome!

Olfactory impairment has been linked with an increased risk of death in the aging population, yet the reasons behind it are unknown. Nowadays, effectively detecting vulnerable patients who will evolve poorly after surgery remains a complex task. In this thesis, we investigated whether olfactory dysfunction could be a reliable predictor of poor postoperative outcome in older patients. Also, we aimed to identify the potential underpinning mechanisms, notably by exploring the connection with frailty, cognition, and telomere length. In the end, we propose a new angle on the concept of frailty, the presumed culprit making the bridge between olfactory impairment and poor outcome. Furthermore, we discuss the unique and promising place of olfactory testing in tomorrow’s perioperative world.(MED - Sciences médicales) -- UCL, 202

Caveolin-1 is required for proper hormone synthesis in thyroid follicles.

Caveolin-1 down-regulates thyroid cell proliferation. Further morphological observations in different thyroid diseases

Absence of typical intraopertative EEG signature of general anaesthesia and continuous suppresion ratio as detected with NeuroSENSE® depth-of-anaesthesia monitor allow considerable decrease of the dose of anaesthetic agents during cardiac surgery : A case report.

Background:A prominent feature of EEG under general anesthesia(GA)is anteriorisation of alpha(α) waves. Studies suggest that α power under GA reflects the degree of brain vulnerability. This would correlate with the increased percentage of EEG suppression in older adults with poor neurocognitive reserve. Case Report:A 63-year-old male(106kg) with history of diabetes,arterial hypertension,CVA(no sequella)and renal transplantation(GFR= 77mL/min/1.73m2)was schedulded for on pump CABG.After full monitoring including frontal EEG (NeuroSENSE®) and NIRS,GA was induced with 2mg midazolam,50 mg propofol,50μg sufentanil and 25mg ketamine.Because of the appearance of bilateral suppression ratio (SR)despite perfect hemodynamics no anesthetic was administered during the insertion of CV line.He continued showing SR (Fig1).Flumazenil(0.4mg) was administered with no effect.A 8 channels-EEG(Datex-Ohmeda)confirmed the observations(Fig 2).International 10-20 EEG was performed showing very slowed(δ and sub-δ)hypovoltaged EEG without asymmetry.A decision to do off pump CABG was taken.Surgery was performed under 0.4% exp sevoflurane and remifentanil at 0.02μg/kg/min. NeuroSENSE® spectral analysis showed only delta waves in absence of α frequencies till the end. He was extubated 2h after arrival in the ICU and showed neither awareness nor neurological complications till hospital discharge. Discussion:This is an example of extreme sensitivity of the aged/frail brain to anesthetics and illustrates that age-related EEG changes can be extremely enhanced in some cases. Learning points:Our case confirms that typical EEG signatures of GA may be absent in patients with poor brain reserve and EEG SR reflects this vulnerability.It moreover illustrates the importance of intraoperative EEG monitoring to avoid anesthetic overdoses

Electroencephalogram Suppression Despite Extremely Low-Dose Anesthetic During Cardiac Surgery: A Case Report.

A prominent feature of electroencephalogram (EEG) under general anesthesia is anteriorization of α waves. We report the case of a 63-year-old man anesthetized for coronary artery bypass grafting in whom the NeuroSENSE-processed EEG monitor recorded only δ waves in the absence of α frequencies, along with high EEG suppression despite extremely low doses of anesthetics during the whole procedure. The patient fully recovered from anesthesia 2 hours after the procedure and showed neither awareness nor neurological complications. This atypical EEG pattern under low concentration of anesthetics may be an intraoperative marker of a specific brain phenotype

Mechanisms linking olfactory impairment and risk of mortality

Olfaction is a sense involved in a complex set of tasks, influencing eating behavior, increasing awareness of environmental hazards and affecting social communication. Surprisingly, smell disorders are very frequent, especially in the elderly population. Several recent studies conducted mostly in older subjects have demonstrated a strong association between olfactory impairment and overall mortality risk, with anosmia being even more predictive of 5 years mortality risk than cardiovascular disease. Presently, the underlying pathophysiology linking olfactory impairment to mortality remains unknown and only putative mechanisms are suggested. This review aims to examine the link between olfactory impairment and mortality and to discuss existing ideas on underlying existing mechanisms including, (1) the effect of olfactory loss on nutrition, life-threatening situations and social interactions, (2) associated neurodegenerative diseases, (3) accelerated brain aging, and (4) reflection of general health status being reflected in olfactory function

Successful ventilation through a Rüsch intubation guide catheter in severe laryngotracheal stenosis

Abstract Background Providing adequate ventilation may remain complex in patients with severe proximal laryngotracheal stenosis, especially when the airway is shared with the surgeon during tracheal resection surgery. We describe an effective alternative to standard endotracheal intubation using a Rüsch flexible intubation guide catheter. Methods In two patients undergoing tracheal repair surgery, we failed to insert a 5.0 inner diameter endotracheal tube (6.9 mm outer diameter) or a 6.0 mm outer diameter endoscope through the laryngotracheal stenosis. However, using indirect laryngoscopy, a 6.0 outer diameter Rüsch flexible intubation guide catheter was passed successfully through the vocal cords and then through the stenosis. Controlled ventilation was achieved by means of the Rüsch guide, provided with its two large Murphy’s eyes. When the trachea was opened, the Rüsch guide was removed just enough for the surgeons to place a Montandon tracheal tube, at that point taking over ventilation. A 7.0 inner diameter endotracheal cuffed tube had been inserted onto the Rüsch guide and left pending upstream from the vocal cords. Once the posterior tracheal wall was sutured, this endotracheal cuffed tube was slid along the Rüsch guide through the vocal cords with the cuff placed beyond the tracheal sutures. Results Controlled ventilation through the Rüsch flexible intubation guide catheter showed satisfying and stable ventilatory parameters in both patients. Inspiratory pressures of 25–30 mmHg were enough to reach adequate tidal volumes around 450 ml. End tidal CO2 was kept between 35 and 40 mmHg (PaCO2 showed similar values). Standard endotracheal intubation at the end of the tracheal resection was easy and safe thanks to the Rüsch guide still in place between the vocal cords. Conclusions We suggest an effective and reliable method using a Rüsch flexible intubation guide catheter for airway management in patients suffering from laryngotracheal stenosis in the setting of tracheal repair surgery

Downregulation of Caveolin-1 and Upregulation of Deiodinase 3, Associated with Hypoxia-Inducible Factor-1α Increase, Are Involved in the Oxidative Stress of Graves' Orbital Adipocytes

Background: Even though the clinical features of Graves' orbitopathy (GO) are well known, its exact pathogenesis remains controversial. The imbalance of redox homeostasis in the connective tissue could play a crucial role leading to an inflammatory state and edema of soft orbital tissues, thus contributing to orbital hypoxia and increase in hypoxia-inducible factor (HIF)-1α. This oxidative stress appears to target the orbital cells such as fibroblasts and also adipocytes. This study aims to explore which pathways can lead to the aforementioned oxidative stress in GO adipose cells and therefore offers new plausible therapeutic targets. Methods: Orbital fat samples were obtained from patients with GO (Western blot [WB]: n = 8, immunohistochemistry [IHC]: n = 8) and from control patients (WB: n = 5, IHC: n = 3-5). They were processed for WB analysis and IHC of the antioxidants (catalase, superoxide dismutase 1) and for HIF-1α. The expression of caveolin-1 (Cav-1) and deiodinase 3 (DIO3), known to be regulated by HIF-1α, was also analyzed by WB and IHC, as well as the targets of Cav-1: glucose transporter type 4 (Glut-4), NADPH oxidase (NOX)-2, and endothelial nitric oxide synthase (eNOS). Triiodothyronine (T3) expression was also analyzed by IHC. Results: In GO adipocytes, the expression of catalase was reduced, whereas that of HIF-1α was strongly increased. A decreased local T3 supply was associated with DIO3 upregulation. The low expression of Cav-1 in GO adipocytes was associated not only with low expression of Glut-4 but also with an increased expression of NOX-2 and active eNOS phosphorylated on serine 1177. Conclusions: Cav-1 and DIO3, both sensitive to hypoxia and to the increase of HIF-1α, play a pivotal role in the oxidative stress in GO adipocytes. DIO3 regulates the cellular supply of T3, which is essential for the cell homeostasis. Cav-1 determines the cellular glucose supply through Glut-4 and regulates the activity of NOX-2 generating superoxide anions and that of eNOS generating nitric oxide (NO)

Functional Imaging in Olfactory Disorders

PURPOSE OF REVIEW: The aim was to synthesize key findings regarding the use of functional MRI (fMRI) to assess olfactory dysfunction (OD), and thus, to evaluate whether fMRI could be a reliable clinical diagnostic tool. RECENT FINDINGS: In response to olfactory stimulation, patients with quantitative OD display reduced activation in olfactory-related brain regions but also stronger activation in non-olfactory brain areas. Parosmic patients also seem to show both weaker and higher brain signals. As to trigeminal chemosensory system, fMRI suggests that central processing may be declined in patients with OD. Functional connectivity studies report a possible correlation between altered neuronal connections within brain networks and olfactory performances. SUMMARY: fMRI emerges as a valuable and promising objective method in OD evaluation. Yet, its high inter-individual variability still precludes its routine clinical use for diagnostic purpose. Future research should focus on optimizing stimulation paradigms and analysis methods

Olfactory Dysfunction Predicts Frailty and Poor Postoperative Outcome in Older Patients Scheduled for Elective Non-Cardiac Surgery

OBJECTIVES: Frailty has been suggested to take part in the recently demonstrated link between olfactory dysfunction and overall mortality risk. Preoperative assessment of frailty is essential to detect the most vulnerable patients scheduled for surgery. The aim of this study was to evaluate whether olfactory dysfunction is a reliable predictor of preoperative frailty and postoperative outcome. DESIGN: This was a single-center prospective observational study conducted between July and October 2020 in Brussels, Belgium. SETTING AND PARTICIPANTS: 155 preoperative patients aged from 65 years old and scheduled for elective non-cardiac surgery. MEASUREMENTS: Olfactory function was examined using the Sniffin’ Sticks 12-item identification test. Frailty was assessed using the Edmonton Frail Scale (EFS) and handgrip strength. The clock drawing test (CDT) from the EFS was also analyzed separately to evaluate cognitive function. Patients were followed for postoperative complications and mortality over one year. RESULTS: Olfactory dysfunction was significantly associated with the EFS score, anosmic patients having a higher median EFS score than normosmic patients (6[4-7] vs 4[2-5], p = .025). Anosmic patients had an increased odds of being frail after adjusting for possible confounding factors (OR: 6.19, 95% CI: 1.65-23.20, p = .007) and were more at risk of poor postoperative outcome (including complications and death) (OR: 4.33, 95% CI: 1.28-14.67, p = .018). CONCLUSIONS: Olfactory dysfunction is associated with preoperative frailty determined by the EFS and with poor post-surgical outcome at one-year