Cortical activation by a salient sound modulates visual temporal order judgments: An electrophysiological study of multisensory attentional processes

Previous event-related potential (ERP) studies show that a salient lateral sound activates the visual cortex more strongly contralateral to the sound, observed as an auditory-evoked contralateral occipital positivity (ACOP). Studies showed that this activation enhances the early cortical processing of co-localized visual stimuli presented after, reflected by better detection rates, better discrimination, and sharper perceived contrast. We replicated the ACOP, using earphones, and tested whether auditory cuing can influence temporal order judgments (TOJ) for two visual stimuli (horizontal arrangement) as well as if the ACOP would predict the amplitude of this influence. A lateral salient sound was followed, after 150 or 630 ms, by the visual presentation of a pair of disks, one in left and one in right hemifield, with variable SOA. The TOJ task was to indicate which disk appeared first or which disk appeared second (controlling for response bias). We observed an ACOP at posterior electrode sites and confirmed our hypothesis that the lateral sound influenced TOJ by accelerating the perception of the disk presented on the cued side, even though the sound was irrelevant to the task. Furthermore, the ACOP amplitude was correlated to this visual perceptual change, indicating that a larger change in brain activity was associated with a faster processing of co-localized visual stimuli.     

The role of hip arthroplasty in management of the hip fracture patient

Hip fractures are becoming increasingly common in a growing elderly population, and are associated with significant morbidity and mortality. Displaced intracapsular femoral neck fractures are usually treated with either total hip arthroplasty (THA) or hemiarthroplasty, although the indication for each operation remains an area for debate. THA has been associated with longer operative time, increased risk of dislocation and a slight increase in general complications compared with hemiarthroplasty. However, it has also been associated with a modest improvement in functional outcomes and quality of life. Guidelines have been created within the UK to aid the decision-making process based upon current available literature. The principal focus of these has been to identify patients suitable for THA, and include patients who are cognitively intact, mobile outside their home with the use of no more than one stick, and who are medically fit enough for the procedure. However, implant selection must also be taken into consideration in order to achieve the best outcomes for patients. Options for implants include use of dual mobility cups and choice of femoral head size in THA, bipolar versus unipolar hemiarthroplasty, and cemented versus uncemented implants. Further research is required into this area to make additional recommendations.     

Quantification of exhaled propofol is not feasible during single-lung ventilation using double-lumen tubes: A multicenter prospective observational trial

Background

Volatile propofol can be measured in exhaled air and correlates to plasma concentrations with a time delay. However, the effect of single-lung ventilation on exhaled propofol is unclear. Therefore, our goal was to evaluate exhaled propofol concentrations during single-lung compared to double-lung ventilation using double-lumen tubes.

Methods

In a first step, we quantified adhesion of volatile propofol to the inner surface of double-lumen tubes during double- and single-lumen ventilation in vitro. In a second step, we enrolled 30 patients scheduled for lung surgery in two study centers. Anesthesia was provided with propofol and remifentanil. We utilized left-sided double-lumen tubes to separately ventilate each lung. Exhaled propofol concentrations were measured at 1-min intervals and plasma for propofol analyses was sampled every 20 min. To eliminate the influence of dosing on volatile propofol concentration, exhalation rate was normalized to plasma concentration.

Results

In-vitro ventilation of double-lumen tubes resulted in increasing propofol concentrations at the distal end of the tube over time. In vitro clamping the bronchial lumen led to an even more pronounced increase (Δ AUC +62%) in propofol gas concentration over time. Normalized propofol exhalation during lung surgery was 31% higher during single-lung compared to double-lung ventilation.

Conclusion

During single-lung ventilation, propofol concentration in exhaled air, in contrast to our expectations, increased by approximately one third. However, this observation might not be affected by change in perfusion-ventilation during single-lung ventilation but rather arises from reduced propofol absorption on the inner surface area of the double-lumen tube. Thus, it is only possible to utilize exhaled propofol concentration to a limited extent during single-lung ventilation.

Registration of Clinical Trial

DRKS-ID DRKS00014788 ( www.drks.de ).     

Modification of an extended total temporomandibular joint replacement (eTMJR) classification system

The aims of this paper were to validate a modification of an extended total temporomandibular joint replacement (eTMJR) classification system and develop a classification schematic for ease of reference. High-volume TMJ surgeons were asked to score 20 separate eTMJR devices using the updated classification system, and inter-rater variability was calculated. Using the modified classification system developed, a Conger’s kappa (κ) coefficient of 0.53 was returned, suggesting moderate to good levels of agreement. The final classification system was then developed in a series of standardised graphic illustrations as visual representations of the different subcategories of eTMJR devices.