Delirium after Cardiac Surgery-A Narrative Review.

Postoperative delirium (POD) after cardiac surgery is a well-known phenomenon which carries a higher risk of morbidity and mortality. Multiple patient-specific risk factors and pathophysiologic mechanisms have been identified and therapies have been proposed to mitigate risk of delirium development postoperatively. Notably, cardiac surgery frequently involves the use of an intraoperative cardiopulmonary bypass (CPB), which may contribute to the mechanisms responsible for POD. Despite our greater understanding of these causative factors, a substantial reduction in the incidence of POD remains high among cardiac surgical patients. Multiple therapeutic interventions have been implemented intraoperatively and postoperatively, many with conflicting results. This review article will highlight the incidence and impact of POD in cardiac surgical patients. It will describe some of the primary risk factors associated with POD, as well as anesthetic management and therapies postoperatively that may help to reduce delirium.

A Comparison of Transesophageal to Transthoracic Echocardiographic Measures of Right Ventricular Function.

OBJECTIVES: To assess the concordance between transesophageal echocardiographic (TEE) and transthoracic echocardiograpic (TTE) measures of right ventricular (RV) function using standard 2-dimensional and Doppler methods. The authors hypothesized that there would be significant disagreement in tricuspid annular plane systolic excursion (TAPSE), fractional area change, right-sided index of myocardial performance, and tricuspid annular systolic velocity (S'). DESIGN: Prospective observational. SETTING: Cardiac operating room at a single academic medical center. PARTICIPANTS: All adult patients undergoing elective cardiac surgery at a single tertiary care academic medical center over 6 months. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The fractional area change, S', TAPSE, right-sided index of myocardial performance, and tricuspid annular diameter were measured with TEE and TTE to assess for concordance using the concordance correlation coefficient and paired t tests, including 95% confidence limits. The study demonstrated that quantitative measures of RV function by TEE correlate poorly with TTE measurements in close temporal proximity under similar hemodynamic conditions. CONCLUSIONS: When performing an assessment of RV function, transesophageal echocardiographers should exercise caution when extrapolating data validated by TTE to TEE studies. Measures of RV function by TEE tend to have fair agreement to TTE measurements obtained in close temporal proximity under similar hemodynamic conditions. Most importantly, the present study showed that TAPSE and S' values obtained from the modified transgastric RV inflow view tend to have lower values than those measured with TTE. Given the propensity for underestimating measurements from the modified transgastric RV inflow view, the authors conclude that values equal to or greater than established norms for tricuspid annular motion may be used to establish normal-but not abnormal-RV function.

Activity-dependent genes in mouse olfactory sensory neurons.

Activity-dependent survival of olfactory sensory neurons (OSNs) may allow animals to tune their olfactory systems to match their odor environment. Activity-dependent genes should play important roles in this process, motivating experiments to identify them. Both unilateral naris occlusion of mice for 6 days and genetic silencing of OSNs decreased S100A5, Lrrc3b, Kirrel2, Slc17a6, Rasgrp4, Pcp4l1, Plcxd3, and Kcnn2 while increasing Kirrel3. Naris occlusion also decreased Eml5, Ptprn, and Nphs1. OSN number was unchanged and stress-response mRNAs were unaffected after 6 days of naris occlusion. This leaves odor stimulation as the most likely cause of differential abundance of these mRNAs, but through a mechanism that is slow or indirect for most because 30-40 min of odor stimulation increased only 3 of 11 mRNAs decreased by naris occlusion: S100A5, Lrrc3b, and Kirrel2. Odorant receptor (OR) mRNAs were significantly more variable than the average mRNA, consistent with difficulty in reliably detecting changes in these mRNAs after 6 days of naris occlusion. One OR mRNA, Olfr855, was consistently decreased, however. These results suggest that the latency from the cessation of odor stimulation to effects on activity-dependent OSN survival must be a week or more in juvenile mice.