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The widespread interest in micro total analysis systems has resulted in efforts to develop devices in cheaper polymer materials such as polydimethylsiloxane (PDMS) as an alternative to expensive glass and silicon devices. We describe the oxidation of the PDMS surface to form ionizable groups using a discharge from a Tesla coil and subsequent chemical modification to augment electroosmotic flow (EOF) within the microfluidic devices. The flow performance of oxidized, amine-modified and unmodified PDMS materials has been determined and directly compared to conventional glass devices. Exact PDMS replicas of glass substrates were prepared using a novel two step micromolding protocol. Chemical force microscopy has been utilized to monitor and measure the efficacy of surface modification yielding information about the acid/base properties of the modified and unmodified surfaces. Results with different substrate materials correlates well with expected flow modifications as a result of surface modification. Oxidized PDMS devices were found to support faster EOF (twice that of native PDMS) similar to glass while those derivatized with 3-aminopropyl triethoxysilane (APTES) showed slower flow rates compared to native PDMS substrates as a result of masking surface charge. Results demonstrate that the surface of PDMS microdevices can be manipulated to control EOF characteristics using a facile surface derivatization methodology allowing surfaces to be tailored for specific microfluidic applications and characterized with chemical force microscopy.

Study Objective: To determine whether use of a smaller needle size for subcutaneous injection of enoxaparin would reduce the size of injection-site hematomas and/or decrease the pain of injection., Design: Prospective, randomized trial., Setting: Community hospital in North Vancouver, British Columbia, Canada., Patients: One hundred twenty-four patients with unstable angina or non-Q-wave myocardial infarction who were administered enoxaparin for anticoagulation., Intervention: Each patient was randomly assigned to one of two groups. One group received enoxaparin injections with a 30-gauge, 5/16-inch insulin syringe, and the other group was injected with a 26-gauge, 3/8-inch tuberculin syringe., Measurements and Main Results: Participating nurses used standard measuring tape to determine the largest diameter of each hematoma. Pain was assessed with a 10-unit numeric scale. The two groups did not differ significantly with regard to either the mean size of the largest hematoma/patient (4.2 cm in the insulin-syringe group vs 3.8 cm in the tuberculin-syringe group, p=0.68) or the mean pain score (0.3 in the insulin-syringe group vs 0.5 in the tuberculin-syringe group, p=0.10)., Conclusions: Use of a 30-gauge, 5/16-inch insulin syringe instead of a 26-gauge, 3/8-inch tuberculin syringe does not significantly reduce either hematoma size or pain of injection. A larger study is required to determine whether needle size affects the frequency of hematoma formation.

Background: Patients admitted to Lions Gate Hospital, North Vancouver, British Columbia, with a primary diagnosis of community-acquired pneumonia (CAP) have a mean length of stay (LOS) of 9.1 days compared with 7.9 days for peer group hospitals. This difference of 1.2 days results in an annual potential savings of 406 bed days and warranted an investigation into the management of CAP., Objective: To characterize and provide recommendations for the management of CAP., Methods: A retrospective chart review of patients admitted with a primary diagnosis of CAP between May 1, 2000 and August 31, 2000., Results: Fifty-one patients were included in the study, with a mean LOS of 9.9 days and a median LOS of five days. Based on pneumonia severity index scores calculated for each patient, eight patients (16%) were admitted inappropriately. Initial empirical antibiotic choices were consistent with the Canadian CAP guidelines in 27 patients (53%), with inconsistencies arising mainly because cephalosporin or azithromycin monotherapy regimens were prescribed. Step-down from intravenous to oral antibiotics occurred in approximately 20 patients (39%). An additional 12 patients (24%) could have undergone step-down, and step-down was not applicable in 19 patients (37%). The potential annual cost avoidance from implementing admission criteria based on a pneumonia severity index score, applying step-down criteria and promoting early discharge criteria was estimated to be $220,000., Conclusions: Considerable variability exists in the treatment of CAP. A CAP preprinted order sheet was developed to address the issues identified in the present study and provide consistency in the management of CAP at Lions Gate Hospital.

Previous studies have reported an incidence of amiodarone-induced pulmonary toxicity (AIPT) of 5% to 10% with high doses of amiodarone (greater than 400 mg daily). A lower rate of 1.6% is recorded from combined placebo controlled, double-blind trials involving 3439 patients receiving daily amiodarone doses of 400 mg or less. Although the rate of diagnosis of AIPT appears to be lower than previously reported, it is still considerable, and its consequences are potentially fatal if undiagnosed. Before amiodarone is initiated, baseline chest x-ray (CXR) and pulmonary function tests should be performed. Although follow-up surveillance with CXR at three- to six-month intervals has been recommended, pulmonary toxicity can develop rapidly, and radiographic abnormalities may not precede clinical toxicity. Repeat lung function testing should be reserved for patients who develop new symptoms or CXR findings. Patient self-reporting of symptoms and regular clinical evaluation are likely the easiest and most useful strategies for prompt detection of AIPT.

Amiodarone-induced pulmonary toxicity (AIPT) is one of the most serious adverse effects of amiodarone therapy and can be fatal. Therefore, vigilant monitoring is advised. Baseline chest radiograph and pulmonary function tests and follow-up chest films at 3-month intervals are advocated. However, since abnormalities on these two examinations do not always precede symptoms, patient self-reports of respiratory symptoms appear to be the best method for early detection of AIPT.