The use of CPOX on the surgical ward is associated with significant improvement in the detection of oxygen desaturation versus intermittent nursing spot-checks. There is a trend toward less ICU transfers with CPOX versus standard monitoring. The evidence on whether the detection of oxygen desaturation leads to less rescue team activation and mortality is inconclusive. Capnography provides an early warning of PORD before oxygen desaturation, especially when supplemental oxygen is administered. Improved education regarding monitoring and further research with high-quality randomized controlled trials is needed.

An understanding of the potential mechanisms underlying recurrent upper airway collapse may help anesthesiologists better manage patients in the postoperative period. There is convincing evidence in the sleep medicine literature to suggest that a positive fluid and salt balance can worsen upper airway collapse in patients with obstructive sleep apnea through the redistribution of fluid from the legs into the neck and upper airway while supine, in a process known as "rostral fluid shift." According to this theory, during the day the volume from a fluid bolus or from fluid overload states (i.e., heart failure and chronic kidney disease) accumulates in the legs due to gravity, and when a person lies supine at night, the fluid shifts rostrally to the neck, also owing to gravity. The fluid in the neck can increase the extraluminal pressure around the upper airways, causing the upper airways to narrow and predisposing to upper airway collapse. Similarly, surgical patients also incur large fluid and salt balance shifts, and when recovered supine, this may promote fluid redistribution to the neck and upper airways. In this commentary, we summarize the sleep medicine literature on the impact of fluid and salt balance on obstructive sleep apnea severity and discuss the potential anesthetic implications of excessive fluid and salt volume on worsening sleep apnea.

With more intensive medical therapy, the risk of stroke or death in patients with asymptomatic carotid stenosis is now so low that most patients will not benefit from endarterectomy or stenting 1 . It is therefore important to have methods to identify the small proportion who could benefit from intervention 1,2 , or who may require special consideration in choice of medical therapy. We have previously reported that carotid plaque area 3 , microemboli on transcranial Doppler 4,5 (TCD), and carotid plaque ulceration on 3-dimensional ultrasound 5 predict the risk of cardiovascular events, particularly of stroke. The predictive value of TCD microembolus detection in patients with ABSTRACT: Background: The risk of stroke in patients with asymptomatic carotid stenosis (ACS) is now so low that it is important to have methods to identify those patients most likely to benefit from intervention, or who may require special consideration in choice of medical therapy. We studied the prediction of stroke, death or transient ischemic attacks (stroke/death/TIA) in patients with ACS by intracranial arterial stenosis, and microemboli on transcranial Doppler (TCD), and the effect of diabetes mellitus on microemboli, intracranial stenosis and risk of events. Methods: Patients with ACS > 60% by Doppler ultrasound were recruited from the Stroke Prevention Clinic of University Hospital, London, Canada. All 339 participants underwent TCD for detection of intracranial stenosis and detection of microemboli, and carotid ultrasound to measure extracranial stenosis and total carotid plaque area. Participants were followed for three years, to determine the risk of stroke/death/TIA. Results: Stroke/death/TIA occurred in 38% of patients with microemboli versus 10% without (p=0.0001), and in 18% of patients with intracranial stenosis, versus 10% without (p=0.042). Diabetics were significantly more likely to have intracranial stenosis (45% vs. 29%, p =0.014), microemboli (38% vs. 10%, p <0.0001), and had significantly higher risk of stroke/death/TIA over three years (21% vs. 11% without; p=0.024). Survival free of stroke, TIA or death was significantly better without microemboli or intracranial stenosis (p<0.0001). Conclusions: Diabetes, microemboli and intracranial stenosis predicted higher risk of stroke, death or TIA than did extracranial stenosis or total plaque area; diabetics may need more intensive therapy.RÉSUMÉ: Diabète, sténose intracrânienne et microembolies dans la sténose carotidienne asymptomatique. Contexte : Le risque d'accident vasculaire cérébral (AvC) chez les patients porteurs d'une sténose carotidienne asymptomatique (SCA) est maintenant si faible qu'il est important d'établir des critères pour identifier les patients qui sont les plus susceptibles de bénéficier d'une intervention ou chez qui on doit porter une attention particulière au choix du traitement médical. nous avons examiné si la présence d'une sténose artérielle intracrânienne et de microembolies au Doppler transcrânien (DTC) étaient des facteurs de prédiction de ...