The phenomenon of 'slowing down' in response to important cues in the operative field is proposed as a hallmark of expert surgical judgment. As part of a larger program of research, the purpose of this study was to explore a methodology for capturing 'slowing down' moments using a standardised task. Edited videos of 6 laparoscopic cholecystectomies were shown to 10 expert surgeons (>250 laparoscopic cholecystectomies completed). Participants were asked to think aloud while watching them as if observing each procedure in the operating room. Each session was audiotaped and transcribed. Many examples of 'slowing down' moments were identified in the transcripts, including several categories that were previously uncharacterised or undescribed. A subset of 'slowing down' moments was compared between participants. Many appeared to be inconsistent between expert surgeons, suggesting that with this methodology alone, formal teaching and assessment of the 'slowing down' phenomenon will be challenging.

Background: Ventricular fibrillation (VF) is associated with dysfunctional cardiac calcium cycling and poor survival. We hypothesized dantrolene improves survival following VF by stabilizing calcium dysregulation. Methods: VF was induced in 26 healthy Yorkshire pigs and left untreated for 4 min followed by 3 min of CPR and defibrillation. Dantrolene was infused during CPR. Rabbit hearts (n=14) were studied to evaluate the effect of dantrolene on VF-induced calcium cycling dysfunction. Results: Survival was higher in the dantrolene group. (85% vs. 39%, P=0.01) Dantrolene-treated pigs required significantly lower defibrillation energy level. (150J vs. 650J, P<0.05) Systolic pressure was significantly higher during the post-defibrillation period in the dantrolene group. (P=0.001) In rabbit hearts, dantrolene significantly mitigated the amplitude of VF-induced diastolic calcium elevations and increased the calcium alternans threshold. (P<0.05) Conclusion: Our findings suggest dantrolene facilitates successful defibrillation, prevents myocardial stunning and improves survival following VF. The effects are mediated through normalizing the VF-induced dysfunctional calcium cycling.

The phenomenon of 'slowing down' in response to important cues in the operative field is proposed as a hallmark of expert surgical judgment. As part of a larger program of research, the purpose of this study was to explore a methodology for capturing 'slowing down' moments using a standardised task. Edited videos of 6 laparoscopic cholecystectomies were shown to 10 expert surgeons (>250 laparoscopic cholecystectomies completed). Participants were asked to think aloud while watching them as if observing each procedure in the operating room. Each session was audiotaped and transcribed. Many examples of 'slowing down' moments were identified in the transcripts, including several categories that were previously uncharacterised or undescribed. A subset of 'slowing down' moments was compared between participants. Many appeared to be inconsistent between expert surgeons, suggesting that with this methodology alone, formal teaching and assessment of the 'slowing down' phenomenon will be challenging.

Background: Ventricular fibrillation (VF) is associated with dysfunctional cardiac calcium cycling and poor survival. We hypothesized dantrolene improves survival following VF by stabilizing calcium dysregulation. Methods: VF was induced in 26 healthy Yorkshire pigs and left untreated for 4 min followed by 3 min of CPR and defibrillation. Dantrolene was infused during CPR. Rabbit hearts (n=14) were studied to evaluate the effect of dantrolene on VF-induced calcium cycling dysfunction. Results: Survival was higher in the dantrolene group. (85% vs. 39%, P=0.01) Dantrolene-treated pigs required significantly lower defibrillation energy level. (150J vs. 650J, P<0.05) Systolic pressure was significantly higher during the post-defibrillation period in the dantrolene group. (P=0.001) In rabbit hearts, dantrolene significantly mitigated the amplitude of VF-induced diastolic calcium elevations and increased the calcium alternans threshold. (P<0.05) Conclusion: Our findings suggest dantrolene facilitates successful defibrillation, prevents myocardial stunning and improves survival following VF. The effects are mediated through normalizing the VF-induced dysfunctional calcium cycling.

The outcomes of hip resurfacing arthroplasty are largely dependent on prosthesis positioning. The biomechanics of notching, accurate measurement of femoral implant version and the use of computer navigation of the Birmingham Hip Resurfacing procedure were studied in this work. First, biomechanical tests were conducted with varying notch sizes and femoral positions, and it was determined that anterior notching weakens the construct (p=0.027) when the femur is in flexion and less so when in single-leg stance (p=0.155). Second, three novel techniques were used by three observers to measure the implant version in a lateral radiograph to determine which displayed a more accurate intra-class correlation. The third study examined the role of computer navigation as a learning device for improving the accuracy of femoral implant positioning using a manual alignment jig to curtail sequelae associated with malalignment.

The purpose of this study was to compare the effects of two types of stem/progenitor cells on the healing of critical sized bone defects in a rat model. Endothelial progenitor cells (EPCs), a novel cell type with previously demonstrated effects on both osteogenesis and angiogenesis, were compared to both a control group (no cells), and a treatment group of mesenchymal stem cells (MSCs). The hypothesis was that EPCs would demonstrate both superior bone healing and angiogenesis, when compared to MSCs and controls. EPCs, MSCs, or a control carrier were placed in surgically stabilized bone defects in a rat femur and both bone formation and angiogenesis were assessed. EPC treated defects demonstrated significantly more bone formation and angiogenesis at the bone defect site than MSC or control treated defects. These results strongly suggest that EPCs are more effective than MSCs for therapeutic osteogenesis and angiogenesis in a bone defect model.

Cryoprecipitate is commonly used outside guidelines. In trauma, the appropriate cryoprecipitate dose and its impact on plasma fibrinogen levels are unclear. This retrospective study aims to evaluate: (1) the appropriateness of cryoprecipitate transfusion in trauma; and (2) the plasma fibrinogen response to cryoprecipitate transfusion during massive transfusion in trauma. Fibrinogen levels of < 1.0 g/L within 2 and 6 hours of cryoprecipitate transfusion were used for assessing appropriateness. Out of 394 events, 238 (60%) and 259 (66%) were considered appropriate using 2 and 6 hour criteria, respectively. A dose of 8.7 (±1.7) units caused a mean increase in fibrinogen levels of 0.55 (±0.24) g/L, or 0.06g/L per unit. In our hospital, where transfusion guidelines and policies for rapid blood product and laboratory turnaround times exist, it is possible to achieve high rates of appropriateness for cryoprecipitate transfusion in trauma. The current recommended dose causes a modest increase in fibrinogen levels.

The outcomes of hip resurfacing arthroplasty are largely dependent on prosthesis positioning. The biomechanics of notching, accurate measurement of femoral implant version and the use of computer navigation of the Birmingham Hip Resurfacing procedure were studied in this work. First, biomechanical tests were conducted with varying notch sizes and femoral positions, and it was determined that anterior notching weakens the construct (p=0.027) when the femur is in flexion and less so when in single-leg stance (p=0.155). Second, three novel techniques were used by three observers to measure the implant version in a lateral radiograph to determine which displayed a more accurate intra-class correlation. The third study examined the role of computer navigation as a learning device for improving the accuracy of femoral implant positioning using a manual alignment jig to curtail sequelae associated with malalignment.

The purpose of this study was to compare the effects of two types of stem/progenitor cells on the healing of critical sized bone defects in a rat model. Endothelial progenitor cells (EPCs), a novel cell type with previously demonstrated effects on both osteogenesis and angiogenesis, were compared to both a control group (no cells), and a treatment group of mesenchymal stem cells (MSCs). The hypothesis was that EPCs would demonstrate both superior bone healing and angiogenesis, when compared to MSCs and controls. EPCs, MSCs, or a control carrier were placed in surgically stabilized bone defects in a rat femur and both bone formation and angiogenesis were assessed. EPC treated defects demonstrated significantly more bone formation and angiogenesis at the bone defect site than MSC or control treated defects. These results strongly suggest that EPCs are more effective than MSCs for therapeutic osteogenesis and angiogenesis in a bone defect model.

Cryoprecipitate is commonly used outside guidelines. In trauma, the appropriate cryoprecipitate dose and its impact on plasma fibrinogen levels are unclear. This retrospective study aims to evaluate: (1) the appropriateness of cryoprecipitate transfusion in trauma; and (2) the plasma fibrinogen response to cryoprecipitate transfusion during massive transfusion in trauma. Fibrinogen levels of < 1.0 g/L within 2 and 6 hours of cryoprecipitate transfusion were used for assessing appropriateness. Out of 394 events, 238 (60%) and 259 (66%) were considered appropriate using 2 and 6 hour criteria, respectively. A dose of 8.7 (±1.7) units caused a mean increase in fibrinogen levels of 0.55 (±0.24) g/L, or 0.06g/L per unit. In our hospital, where transfusion guidelines and policies for rapid blood product and laboratory turnaround times exist, it is possible to achieve high rates of appropriateness for cryoprecipitate transfusion in trauma. The current recommended dose causes a modest increase in fibrinogen levels.