Video Modeling and Video Feedback to Reduce Time to Perform Intravenous Cannulation in Medical Students: A Randomized-Controlled Mixed-Methods Study

Combined video modeling (VM) and video feedback (VF) may be more beneficial than traditional feedback when teaching procedural skills. This study examined whether repeated VM and VF compared with VM alone reduced the time required for medical students to perform peripheral intravenous (IV) cannulation. Twenty-five novice medical students were randomly assigned to groups in a one-way blinded embedded mixed-methods study to perform IV cannulation. Participants received standardized instruction and performed IV cannulation on each other while being audio-video recorded. They were assigned to review a video of an expert performing IV cannulation (VM alone), or both the expert video and a video of their own most recent IV cannulation (VM+VF), before returning to perform another IV cannulation. This was repeated for a total of four IV cannulation encounters and three video reviews. A post-test interview was also conducted and analyzed qualitatively using thematic content analysis. The median [interquartile range] time required to perform IV cannulation in the final encounter was significantly different between the VM+VF group vs VM alone group (126 [93-226] sec vs 345 [131-537] sec, respectively; median difference, 111 sec; 95% confidence interval, 8 to 391; P = 0.02). There was no significant difference in IV cannulation success between VM alone and VM+VF in the final encounter (75% vs 85% respectively; P = 0.65). For the VM+VF group, the time to perform IV cannulation was reduced after the final encounter compared with the baseline encounter (P = 0.002), which was not true of the VM alone group (P = 0.35). Video modeling and feedback shortened time to IV skill completion, reduced complications, and improved satisfaction in novice medical students.     

Atypical Femoral Fractures: Transverse Morphology at Lateral Cortex Is a Critical Feature

In 2010, the American Society for Bone and Mineral Research (ASBMR) task force defined major and minor features to assist in the case finding and reporting of atypical femoral fractures (AFFs). One major feature that was proposed was a “transverse or short oblique configuration.” Our primary aim was to compare the conventional overall fracture morphology (OFM) with its associated angle (OFMA) and our proposed lateral cortical fracture angle (LCFA) in the assessment of fracture configuration in suspected AFFs and non‐AFFs. The radiographs of 79 patients with AFFs and 39 patients with non‐AFFs were each analyzed by two blinded reviewers to obtain the OFM, OFMA, and LCFA. Using the overall fracture morphology to assess the suspected AFFs resulted in discordance between reviewers in 18 cases (22.8%), of which 5 (6.3%) were discordant between short oblique (>30° to 60°) and long oblique (>60° to 90°) configurations, therefore affecting their classifications as AFFs. By assessing only the critical component within the lateral cortex, all the suspected AFFs fell well within the classification as transverse fractures with a mean LCFA of 4.8° (range 0.3 to 18.0, SD = 4.23). The inter‐reader variability was also lower for LCFA versus OFMA (4.1° versus 6.9°, p = 0.001) when used to assess AFFs. Fracture angles were significantly different in AFFs versus non‐AFFs regardless of whether the OFMA or LCFA methodology was employed, but the greater difference associated with LCFA suggests its greater discriminating power. When LCFA was used in conjunction with 0° to 30° as the criteria for transverse morphology, all the AFFs and non‐AFFs were correctly classified. By using a standardized and precise method in measuring the fracture angle, specifically using only the component of the lateral cortex and limiting to truly transverse fractures, ie, between 0° and 30°, the LCFA is a robust and accurate method to assess the fracture morphology in suspected AFFs. © 2014 American Society for Bone and Mineral Research.     

Results of a Surgeon-Directed Quality Improvement Project on Breast Cancer Surgery Outcomes in South-Central Ontario

Background

Gaps in breast cancer (BC) surgical care have been identified. We have completed a surgeon-directed, iterative project to improve the quality of BC surgery in South-Central Ontario.

Methods

Surgeons performing BC surgery in a single Ontario health region were invited to participate. Interventions included: audit and feedback (A&F) of surgeon-selected quality indicators (QIs), workshops, and tailoring interviews. Workshops and A&F occurred yearly from 2005–2012. QIs included: preoperative imaging; preoperative core biopsy; positive margin rates; specimen orientation labeling; intraoperative specimen radiography of nonpalpable lesions; T1/T2 mastectomy rates; reoperation for positive margins; sentinel lymph node biopsy (SLNB) rates, number of sentinel lymph nodes; and days to receive pathology report. Semistructured tailoring interviews were conducted to identify facilitators and barriers to improved quality. All results were disseminated to all surgeons performing breast surgery in the study region.

Results

Over 6 time periods, 1,828 BC charts were reviewed from 12 hospitals (8 community and 4 academic). Twenty-two to 40 participants attended each workshop. Sustained improvement in rates of positive margins, preoperative core biopsies, specimen orientation labeling, and SLNB were seen. Mastectomy rates and overall axillary staging rates did not change, whereas time to receive pathology report increased. The tailoring interviews concerning positive margins, SLNB, and reoperation for positive margins identified facilitators and barriers relevant to surgeons.

Conclusions

This surgeon-directed, regional project resulted in meaningful improvement in numerous QIs. There was consistent and sustained participation by surgeons, highlighting the importance of integrating the clinicians in a long-term, iterative quality improvement strategy in BC surgery.     

Reduced Toxicity of Shiga Toxin (Stx) Type 2c in Mice Compared to Stx2d Is Associated with Instability of Stx2c Holotoxin

Shiga toxin (Stx) is an AB₅ ribotoxin made by Stx-producing Escherichia coli (STEC). These organisms cause diarrhea, hemorrhagic colitis and the hemolytic uremic syndrome. STEC make two types of Stxs, Stx1 and/or Stx2. Stx2 has one prototype (a) and six subtypes (b–g), but only STEC that make Stx2a, and/or Stx2c, or Stx2d are associated with severe disease. However, Stx2c is about 10-fold less toxic than Stx2d in vivo despite only two amino acid differences in the A subunit at positions 291 and 297. We made mutations at these two sites to create intermediate toxins between Stx2c and Stx2d, and determined the 50% cytotoxic dose on Vero cells before and after heat treatment, and the 50% lethal dose in mice of the toxins. We found that serine 291 was associated with increased toxicity in vivo and that either amino acid change from that in Stx2c to that in Stx2d increased heat stability. We also assessed the secondary structure of Stx2c and Stx2d by circular dichroism (CD) spectroscopy. The CD studies suggest that Stx2c has a less-ordered secondary structure than Stx2d. We conclude that both amino acids at positions 291 and 297 in Stx2c contribute to its decreased stability and in vivo toxicity compared to Stx2d.     

Potent Irreversible Inhibitors of LasR Quorum Sensing in Pseudomonas aeruginosa

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Stem cell factor retards differentiation of normal human erythroid progenitor cells while stimulating proliferation

Stem cell factor (SCF), the ligand for the c-kit tyrosine kinase receptor, markedly stimulates the accumulation of erythroid progenitor cells in vitro. We now report that SCF delays erythroid differentiation among the progeny of individual erythroid progenitors while greatly increasing the proliferation of these progeny. These effects appear to be independent of an effect on maintenance of cell viability. Highly purified day-6 erythroid colony-forming cells (ECFC), consisting mainly of colony-forming units-erythroid (CFU-E), were generated from human peripheral blood burst-forming units-erythroid (BFU-E). Addition of SCF to the ECFC in serum-free liquid culture, together with erythropoietin (EP) and insulin-like growth factor 1 (IGF-1), resulted in a marked increase in DNA synthesis, associated with a delayed peak in cellular benzidine positivity and a delayed incorporation of 59Fe into hemoglobin compared with cultures without SCF. In the presence of SCF, the number of ECFC was greatly expanded during this culture period, and total production of benzidine-positive cells plus hemoglobin synthesis were ultimately increased. To determine the effect of SCF on individual ECFC, single-cell cultures were performed in both semisolid and liquid media. These cultures demonstrated that SCF, in the presence of EP and IGF-1, acted on single cells and their descendants to delay erythroid differentiation while substantially stimulating cellular proliferation, without an enhancement of viability of the initial cells. This was also evident when the effect of SCF was determined using clones of ECFC derived from single BFU-E. Our experiments demonstrate that SCF acts on individual day-6 ECFC to retard erythroid differentiation while simultaneously providing enhanced proliferation by a process apparently independent of an effect on cell viability or programmed cell death.