Michel Morin

Postoperative myocardial infarction and cardiac death. Predictive value of dipyridamole-thallium imaging and five clinical scoring systems based on multifactorial analysis.

Sixty-six patients unable to complete a standard preoperative exercise test because of physical limitations were studied to determine the predictive value of individual clinical parameters, of clinical scoring systems based on multifactorial analysis, and of dipyridamole-thallium imaging before major general and vascular surgery. Study endpoints were limited to postoperative myocardial infarction or cardiac death before hospital discharge. There were nine postoperative cardiac events (seven deaths and two nonfatal infarctions). There was no statistical correlation between cardiac events and preoperative clinical descriptors, including individual clinical parameters, the Dripps-American Surgical Association score, the Goldman Cardiac Risk Index score, the Detsky Modified Cardiac Risk Index score, Eagles clinical markers of low surgical risk, and the probability of postoperative events as determined by Coopermans equation. There were no cardiac events in 30 patients with normal dipyridamole-thallium scans or in nine patients with fixed myocardial perfusion defects. Of 21 patients with reversible perfusion defects who underwent surgery, nine had a postoperative cardiac event (sensitivity, 100%; specificity, 43%). In the six other patients with reversible defects, preoperative angiography showed severe coronary disease or cardiomyopathy. Thus in patients unable to complete a standard exercise stress test, postoperative outcome cannot be predicted clinically before major general and vascular surgery, whereas dipyridamole-thallium imaging successfully identified all patients who sustained a postoperative cardiac event.

Standing views to differentiate gallbladder or bile leak from duodenal activity on cholescintigrams

Confusing a gallbladder or bile leak with duodenal activity is a common source of error in the interpretation of cholescintigrams. Techniques such as supplementary oblique views, delayed views, the “water test,” dynamic display and combined cholescintigraphy and ultrasound have been used with varying degrees of success. As illustrated in two cases, supplementary standing views provide a simple alternative method to differentiate gallbladder from small bowel activity.

Indigenous Peoples, Political Economists and the Tragedy of the Commons

Abstract In “The Tragedy of the Commons,” Garrett Hardin implicitly moved from bounded commons — a pasture or a tribe’s territory — to the case of boundless commons — the ocean, the atmosphere and planet Earth. He insisted on the need for imposing limits on the use of these resources, blurring the difference between communal property and open access regimes. The success of his paper is due in great measure to his neglect of economic, scientific, legal and anthropological literature. His main lifelong focus was on limiting population growth. He could have avoided the conceptual confusion he created by turning to well-known political economists such as John Locke and Adam Smith or, for that matter, jurists, such as Blackstone. Instead, he simply envisioned indigenous lands as an unbounded wilderness placed at the disposal of frontiersmen. Though he eventually acknowledged the existence of managed commons, he had little interest in community rules pertaining to resource exploitation. For him, these were simply moral norms which inevitably became ineffective after a community reached a certain level of population. He also took economists to task for failing to include in their analysis the true environmental and social costs of public decisions. Still, the famous example of the indigenous people of Northeastern Quebec illustrates a shortcoming of his analysis: community members did not act in total isolation from each other. On the contrary, communal norms could prevent an overexploitation of resources or allow for the adoption of corrective measures.