Inductive reasoning in the context of discovery: Analogy as an experimental stratagem in the history and philosophy of science.

Building on Norton's "material theory of induction," this paper shows through careful historical analysis that analogy can act as a methodological principle or stratagem, providing experimentalists with a useful framework to assess data and devise novel experiments. Although this particular case study focuses on late eighteenth and early nineteenth-century experiments on the properties and composition of acids, the results of this investigation may be extended and applied to other research programs. A stage in-between what Steinle calls "exploratory experimentation" and robust theory, I argue that analogy encouraged research to substantiate why the likenesses should outweigh the differences (or vice versa) when evaluating results and designing experiments.

Treatment of catheter occlusion in pediatric patients.

A proper initial assessment of catheter occlusion is the key to successful management. The assessment screens are for both thrombotic and nonthrombotic causes (including mechanical occlusion). If mechanical occlusion is excluded, thrombotic occlusion is treated with alteplase. Nonthrombotic occlusions are treated according to their primary etiologies: lipid occlusion is treated with 70% ethanol, mineral precipitates are treated with 0.1-N hydrochloric acid (HCl), drug precipitates are treated according to their pH-acidic drugs can be cleared with 0.1-N HCl, basic medications can be cleared with sodium bicarbonate or 0.1-N sodium hydroxide (NaOH). Prevention of occlusion of central venous access devices is also critical. To date, no data conclusively show heparin flushes to be superior to saline flushes. No prophylactic regimen, including low-dose warfarin, low-molecular-weight heparin, or 1 unit heparin/mL of parenteral nutrition has been endorsed by any major medical, nursing, or pharmacy group due to lack of scientific evidence. The most encouraging information on decreasing occlusion rate comes from experience with positive-pressure devices that attach to the hub of most catheter lumens and prevent retrograde blood flow and, consequently, decrease the risk of thrombus formation in the catheter lumen.

The use of alteplase for restoring patency to occluded central venous access devices in infants and children.

A 21-month retrospective review was completed at the Lucile Packard Children's Hospital to assess the experience of 22 infants and children who received alteplase for the clearance of occluded central venous access devices. After the first dose, 86% (n = 19) of the catheters cleared. Two additional catheters cleared with a second dose. With alteplase treatment, 95% (n = 21) of the catheters cleared. No adverse events were noted within 24 hours after the alteplase was received. Infusion of alteplase appeared to be safe and effective in restoring patency to occluded central venous access devices in infants and children.