Multimedia-based training on Internet platforms improves surgical performance: a randomized controlled trial.

BACKGROUND: Surgical procedures are complex motion sequences that require a high level of preparation, training, and concentration. In recent years, Internet platforms providing surgical content have been established. Used as a surgical training method, the effect of multimedia-based training on practical surgical skills has not yet been evaluated. This study aimed to evaluate the effect of multimedia-based training on surgical performance. METHODS: A 2 × 2 factorial, randomized controlled trial with a pre- and posttest design was used to test the effect of multimedia-based training in addition to or without practical training on 70 participants in four groups defined by the intervention used: multimedia-based training, practical training, and combination training (multimedia-based training + practical training) or no training (control group). The pre- and posttest consisted of a laparoscopic cholecystectomy in a Pelvi-Trainer and was video recorded, encoded, and saved on DVDs. These were evaluated by blinded raters using a modified objective structured assessment of technical skills (OSATS). The main evaluation criterion was the difference in OSATS score between the pre- and posttest (ΔOSATS) results in terms of a task-specific checklist (procedural steps scored as correct or incorrect). RESULTS: The groups were homogeneous in terms of demographic parameters, surgical experience, and pretest OSATS scores. The ΔOSATS results were highest in the multimedia-based training group (4.7 ± 3.3; p < 0.001). The practical training group achieved 2.5 ± 4.3 (p = 0.028), whereas the combination training group achieved 4.6 ± 3.5 (p < 0.001), and the control group achieved 0.8 ± 2.9 (p = 0.294). CONCLUSION: Multimedia-based training improved surgical performance significantly and thus could be considered a reasonable tool for inclusion in surgical curricula.

The initial tangent of the aortic pressure increase is an estimate of left ventricular contractility in pigs.

The aim was, to identify an estimate of left ventricular contractility derived from the aortic pressure wave without load changing manoeuvres. For this purpose, left ventricular contractility was assessed with several aortic pressure wave form derived parameters and was compared to standard parameters of left ventricular contractility (conductance technique) in an experimental study. Measurements were taken during baseline, after beta-stimulation and after injection of a beta-antagonist. The initial and the secondary tangent, the area under the aortic pressure, and the stroke volume were correlated with the endsystolic elastance, a mainly load independent measure of left ventricular contractility: The initial tangent of the aortic pressure increase correlated significantly with the endsystolic elastance (r = 0.54, P < 0.05). The initial tangent of the aortic pressure increase was significantly increased from baseline at beta-stimulation (from 20.2 +/- 4.7 to 36.4 +/- 6.8 mmHg s(-1), P < 0.05) and decreased after injection of a beta-antagonist (from 20.2 +/- 4.7 to 12.3 +/- 2.0, P < 0.05). Thus, we conclude that the initial tangent of the aortic pressure increase is a valid estimate of left ventricular contractility in piglets.

Effect of prostaglandin I2 analogues on left ventricular diastolic function in vivo.

The prostaglandin I2 analogues epoprostenol and iloprost increase left ventricular contractility. Therefore, we hypothesize that the prostaglandin I2 analogues epoprostenol and iloprost improve also left ventricular diastolic function. To test this hypothesis, the effects of epoprostenol and iloprost on left ventricular diastolic function were assessed in vivo and compared to two vasodilators sodium nitroprusside and adenosine, not formerly associated with changes of left ventricular contractility. Eleven pigs (25.9+/-2.8 kg, balanced anaesthesia) were exposed to the short-acting intravenous vasodilators sodium nitroprusside, adenosine and epoprostenol in a randomized cross over design. The long-acting iloprost was administered at the end of the protocol. The drugs are titrated to achieve a 25% reduction of diastolic aortic pressure. Active isovolumic relaxation properties of the left ventricle were assessed by the maximum velocity of left ventricular pressure drop. Passive phase of relaxation and filling was assessed by the determination of end diastolic compliance during a preload reduction manoeuvre. The maximum velocity of left ventricular pressure drop worsened during the infusion of sodium nitroprusside (baseline: -1950; sodium nitroprusside: -1293 mm Hg/s, p<0.05, Wilcoxon signed rank test versus vs. baseline) and adenosine (baseline: -2015; adenosine: -1345 mm Hg/s, p<0.05), but remained stable during the infusion of the prostaglandins (baseline: -1943; epoprostenol: -1785 mm Hg/s; baseline: -2042; iloprost: -1923 mm Hg/s). End diastolic compliance was not altered significantly by any vasodilator. Interstitial myocardial cAMP increased during the infusion of epoprostenol (7.60 to 13.87 fmol/ml, p<0.05) and tended to increase during the infusion of iloprost (7.56 to 11.66 fmol/ml, p=0.21). The prostaglandin I(2) analogues epoprostenol and iloprost preserved the early phase of active isovolumic relaxation, presumably mediated by myocardial cAMP, whereas sodium nitroprusside and adenosine impaired early active isovolumic relaxation. Passive relaxation and filling properties remained stable during the infusion of each applied vasodilator in the intact left ventricle in vivo.

The prostaglandins epoprostenol and iloprost increase left ventricular contractility in vivo.

OBJECTIVE: The principal effects of prostaglandin I(2) are vasodilation and inhibition of platelet aggregation induced by a rise in the intracellular second messenger cAMP. In the heart a rise in intracellular myocardial cAMP increases contractility. We examined whether prostaglandin I(2) increases left ventricular contractility in vivo. The effects of epoprostenol and iloprost on left ventricular contractility were assessed in vivo and compared to the effects of adenosine and sodium nitroprusside, which exerts vasodilatory properties independently of cAMP. DESIGN AND SETTING: Prospective, randomized, cross-over in a university laboratory. SUBJECTS: Eleven pigs (25.9+/-2.8 kg, balanced anesthesia). INTERVENTIONS: Each animal was exposed to intravenous sodium nitroprusside, adenosine, and epoprostenol in randomized order. Iloprost was administered at the end due to its longer half-life. The dose was titrated to achieve a 25% reduction in diastolic aortic pressure. MEASUREMENTS AND RESULTS: Left ventricular contractility was assessed before, during, and after each intervention by determination of the endsystolic elastance with the conductance method. While there was no change in endsystolic elastance upon the infusion of adenosine and sodium nitroprusside; endsystolic elastance increased in the case of epoprostenol (57%) and iloprost (71%). CONCLUSIONS: Left ventricular contractility is increased in vivo by epoprostenol and iloprost but not by adenosine or sodium nitroprusside at equipotent hypotensive dose. A contribution of sympathetic reflex activation of cardiac nerves on the increase in left ventricular contractility cannot be completely ruled out.