Margaret M. Dunn

Critical Thinking: Change During Medical School and Relationship to Performance in Clinical Clerkships

The development of critical thinking, the ability to solve problems by assessing evidence using valid inferences, abstractions, and generalizations, is one of the global goals advocated by most medical schools. This study determined changes in critical thinking skills between entry and near the end of the third year of medical school, assessed the predictive ability of a test of critical thinking skills, and assessed the concurrent validity of clerkship components and final grade. The Watson–Glaser Critical Thinking Assessment (WGCTA) was administered to one class of students at entry to medical school and near the end of year 3. Performance data for those students who completed their clinical clerkships on schedule were also recorded. Critical thinking improved modestly but significantly from entry to medical school to near the end of year 3. The ability of a critical thinking test to predict clerkship performance was limited; the correlation between WGCTA total score at entry and the components and final grade of five major clerkships ranged from near 0 to 0·34. The concurrent validity of clerkship components and final grade was also limited; correlations with WGCTA total score near the end of year 3 ranged between 0·08 and 0·49. The correlation between WGCTA total score and United States Medical Licensing Examination Step 2 was higher at year 3 than at medical school entry. Critical thinking skills improve moderately during medical school. Used alone, tests of critical thinking may be of limited value in predicting which students will be successful in clinical clerkships. Clerkship evaluation components and final grade have limited concurrent validity when a test of critical thinking is the criterion.

Incidental Meckel's diverticulectomy in adults

BACKGROUND Incidental Meckels diverticulectomy has been advocated by some surgeons because of the lower associated morbidity and mortality in this setting than when resection is indicated. Others have argued that the low risk of complication occurrence does not justify prophylactic removal. The issue remains controversial. METHODS Medical records of all adults undergoing Meckels diverticulectomy at four acute care hospitals during the 5-year period 1989 through 1993 were retrospectively reviewed. Decision analysis was used to determine relative risks for incidental resection compared to indicated resection for a complication. RESULTS Ninety patients underwent incidental diverticulectomy. Morbidity was 2% and mortality 0%. Four patients underwent resection for a complication of their diverticulum. Morbidity and mortality were each 0%. Combining these results with previously reported results and using decision analysis, the conditional probabilities of producing surgical morbidity or mortality in the adult population at risk by only resecting symptomatic diverticula are 0.2% and 0.04%, respectively. The comparable risks for resecting all incidentally discovered diverticula are 4.6% and 0.2%. CONCLUSIONS Incidental diverticulectomy in adults should be abandoned.

Adjunctive vasodilator therapy in the treatment of murine ischemia

Potent vasoconstrictors such as angiotensin II and vasopressin have been implicated as mediators of persistent vasoconstriction after reversible superior mesenteric artery (SMA) occlusion. Neither captopril (CAP), an angiotensin-converting enzyme (ACE) inhibitor, nor papaverine (PAP), a vasodilator, has proven effective in reversing this vasoconstriction when employed singly. The present study examined the combined effect of these agents in reducing mortality in a murine model of acute mesenteric ischemia. The SMAs of 106 adult male Sprague-Dawley rats were totally occluded for 85 minutes. Test agents were given intravenously at reperfusion over a 90-minute period. Survival rates were assessed at 48 hours. CAP was given as a single bolus (0.3 mg/kg) and PAP (0.5 mg/kg/h) as an infusion. Aortic and SMA blood flows were measured pretreatment and posttreatment in a separate group of 19 animals treated with CAP and PAP as single agents. chi 2 analysis and analysis of variance were used to test differences with p < or = 0.05 accepted as significant. PAP alone as an adjunct resulted in a significant increase in 48-hour survival (57% versus 19%, p < or = 0.005). PAP in combination with CAP produced the best outcome in this model (87% versus 19%, p < or = 0.005). Aortic blood flow decreased, whereas SMA blood flow increased after treatment both with CAP and with PAP, but not significantly. The combination of an intravenously administered vasodilator with either glucagon or an ACE inhibitor was the most effective adjunctive therapy in this mesenteric ischemia model. There was no evidence that an inotropic effect, rather than SMA vasodilation, was the responsible mechanism of action.