Impact of individualized feedback letters on adherence to surgical antibiotic prophylaxis guidelines: an interrupted time series study (FEEDBACK-ASAP).

BACKGROUND: Surgical antibiotic prophylaxis (SAP) has been proved to decrease the rate of surgical site infections (SSI), but compliance to SAP guidelines remains suboptimal. AIM: This study evaluated the impact of periodically sending individualized feedback letters to surgeons and anesthesiologists on their compliance rate to SAP guidelines. METHODS: A total of 1491 surgeries were evaluated by retrospective chart review during the pre-intervention period and 668 surgeries were evaluated by prospective chart review during the per-intervention period. Finally, 295 letters were sent to 64 surgeons and 45 anesthesiologists. Compliance rate was assessed as an outcome composed of: indication for SAP, choice of antibiotic agent, antibiotic dose, postoperative duration, timing of the preoperative dose and intraoperative redosing. An interrupted time series design was used to assess a difference on compliance rates before and during the intervention period. FINDINGS: Sending individualized feedback letters to surgeons and anesthesiologists did not significantly improve the overall compliance to local SAP guidelines. CONCLUSION: Individualized feedback letters could be part of future interventions directed at improving compliance to SAP guidelines, but are likely insufficient by themselves to provide significant results.

Feature tracking and aging.

There are conflicting results regarding the effect of aging on second-order motion processing (i.e., motion defined by attributes other than luminance, such as contrast). Two studies (Habak and Faubert, 2000; Tang and Zhou, 2009) found that second-order motion processing was more vulnerable to aging than first-order motion processing. Conversely, Billino et al. (2011) recently found that aging affected first- and second-order motion processing by similar proportions. These three studies used contrast-defined motion as a second-order stimulus, but there can be at least two potential issues when using such a stimulus to evaluate age-related sensitivity losses. First, it has been shown that the motion system processing contrast-defined motion varies depending on the stimulus parameters. Thus, although all these three studies assumed that their contrast-defined motion was processed by a low-level second-order motion system, this was not necessarily the case. The second potential issue is that contrast-defined motion consists in a contrast modulation of a texture rich in high spatial frequencies and aging mainly affects contrast sensitivity at high spatial frequencies. Consequently, some age-related sensitivity loss to second-order motion could be due to a lower sensitivity to the texture rather than to motion processing per se. To avoid these two potential issues, we used a second-order motion stimulus void of high spatial frequencies and which has been shown to be processed by a high-level feature tracking motion system, namely fractal rotation (Lagacé-Nadon et al., 2009). We found an age-related deficit on second-order motion processing at all temporal frequencies including the ones for which no age-related effect on first-order motion processing was observed. We conclude that aging affects the ability to track features. Previous age-related results on second-order and global motion processing are discussed in light of these findings.

Exploring the spatiotemporal properties of fractal rotation perception.

A series of three experiments was conducted with the aim of determining the processing nature of the fractal rotation stimulus introduced by C. P. Benton, J. M. O'Brien, and W. Curran (2007). This stimulus has been proposed to be invisible to first-order sensitive mechanisms considering it is drift-balanced. Rather, motion perception would require the analysis of spatial structure (orientation) changing over time. In Experiment 1, spatiotemporal properties of fractal rotation perception have been explored, in comparison with first-order rotation perception. In Experiment 2, a motion paradigm similar to the one developed by K. Nakayama and C. W. Tyler (1981) and later used by A. E. Seiffert and P. Cavanagh (1998) has been used to characterize the motion processing mechanism responsible for fractal rotation perception. In Experiment 3, we have used a paradigm similar to N. E. Scott-Samuel and A. T. Smith (2000) to evaluate whether fractal rotation perception is analyzed by common or distinct mechanisms to those for first-order rotation perception. Results indicate that fractal rotation perception involves feature-tracking processes with mechanisms responding to global orientation-based changes of the image. Given the absence of cancellation of first-order and fractal rotation motion signals, we can therefore conclude that the first-order and fractal motion sensitive pathways are dissociable at early stages of the visual processing stream.