Changes in pediatric tracheostomy tubes exposed to home dishwashing.

OBJECTIVE: Determine the effects of household dishwashing on Tracheostomy Tube safety. INTRODUCTION: Tracheostomy tubes accumulate biofilms, which may limit their lifespan. Frequent cleaning of the tubes is a method for biofilm prevention. Cleaning practices vary widely. Some families prefer dishwashing of tubes, but its effects are currently unknown. We hypothesize that dishwashing has no significant effect on the physical properties of tracheostomy tubes and can be recommended as a safe way to clean tracheostomy tubes. METHODS: Twenty 4.0 Shiley™ pediatric tracheostomy tubes were randomly assigned into dishwashed (DW) and non-dishwashed (NDW) groups, 10/group. DW tubes were subjected to 12 wash cycles. Each tube's hardness along with the surface spectra were analyzed to assess for chemical composition changes. Three cannula samples from each group were also randomly assessed with scanning-electron microscopy and scored by blinded examiners to assess for changes in surface heterogeneity. RESULTS: Hardness testing revealed a statistically significant difference (p = 0.0009) between the NDW and the DW group indicating increased fragility in the dishwashed tubes. Spectral analysis revealed loss of plasticizers, indicating decreased flexibility. Blinded electron microscopy scoring revealed increased surface heterogeneity in the DW group (p = 0.00007). CONCLUSION: A significant decrease in tube hardness and increased surface heterogeneity were found with dishwashing. The spectral analysis demonstrated increasing fragility. We believe these effects could potentially lead to decreased mechanical safety. With increased surface heterogeneity there is a greater potential for biofilm formation. At this time, dishwashing cannot be recommended as a tracheostomy tube cleaning method.

Exercise testing in Wolff-Parkinson-White syndrome: case report with ECG and literature review.

ECG changes during exercise stress testing, such as false-positive ST-segment depression and disappearance of the delta wave, are reported in patients with the Wolff-Parkinson-White (WPW) pattern. We present a case of exercise testing in a 53-year-old man with WPW syndrome with ischemic-appearing ECG changes and normal nuclear stress perfusion study findings who was thought to be at clinically low risk for having significant coronary disease. A literature review is discussed. Although ST-segment depression typical for ischemia occurs in half of the patients in whom WPW syndrome is reported, exercise testing is still an important tool in their evaluation. Data other than ECG response can be interpreted in the context of clinical history and physical examination findings to stratify the risk of coronary disease. Complete and sudden disappearance of the delta wave has been seen during exercise in 20% of patients with WPW syndrome and can identify those who are at low risk for sudden arrhythmic death.

Importance of transesophageal echocardiography in the evaluation of Staphylococcus aureus bacteremia.

BACKGROUND AND AIM OF THE STUDY: Staphylococcus aureus is a leading cause of bacteremia and is often associated with endocarditis. The diagnosis of endocarditis may be missed when relying on clinical risk prediction, and this has led others to recommend transesophageal echocardiography (TEE) for diagnosis in most cases of S. aureus bacteremia (SAB). The study aim was to determine the likelihood of finding vegetations on TEE in patients with SAB in a suburban teaching hospital setting, and to identify risk factors predictive of vegetation on TEE. METHODS: All cases of SAB at Walter Reed Army Medical Center between January 2000 and May 2003 were evaluated. The prevalence of vegetations was determined in those cases selected for TEE. Potential risk factors for endocarditis were analyzed by review of medical records. RESULTS: A total of 176 patients had documented SAB during the time frame of the study, and 64 of these had TEE performed. Among the latter patients, 14% had a previously unidentified vegetation discovered by TEE. Patients with vegetation on TEE were as likely as those without vegetation to have nosocomial bacteremia, an alternate source of infection, and lack of valvular disease by prior surface echocardiography. Patients with a vegetation were significantly older (mean age 68.4+/-10.9 versus 54.6+/-19.6 years; p = 0.04). CONCLUSION: TEE identified a significant number of vegetations resulting from SAB. The clinical risk profile and transthoracic echocardiography did not reliably exclude vegetation. These findings support the liberal use of TEE for the diagnosis of SAB.

Marked low-density lipoprotein cholesterol reduction below current national cholesterol education program targets provides the greatest reduction in carotid atherosclerosis.

BACKGROUND: Current National Cholesterol Education Program (NCEP) guidelines recognize low-density lipoprotein cholesterol (LDL-C) below 100 mg/dl as an optimal level. Evidence supporting this is scant. Both LDL-C and C reactive protein (CRP) are known correlates of atherosclerosis progression. HYPOTHESIS: We examined the effect of final LDL-C and CRP obtained with statin therapy on carotid intima-media thickness (CIMT), a valid surrogate for clinical benefit of lipid-lowering therapies. METHODS: In a randomized, single-center trial, 161 patients were assigned to statin therapy of different potencies (pravastatin 40 mg, n = 82; atorvastatin 80 mg, n = 79). The effects on CIMT were assessed in relationship to LDL-C and CRP levels obtained after 12 months of therapy. RESULTS: Changes in CIMT were directly related to the final LDL-C level obtained on statin therapy after 12 months (R = 0.219, p = 0.015). Carotid intima-media thickness regression was seen in 61% of the subjects in the lowest quartile of final LDL-C (< 70 mg/dl) versus 29% of the subjects with the highest quartile of final LDL-C (> or = 114 mg/dl, p = 0.008). No threshold value was seen, with more favorable effects on absolute change in CIMT with lower values of LDL-C (decrease in CIMT of 0.06 +/- 0.17 mm in the lowest quartile compared with an increase of 0.06 +/- 0.09 in the highest quartile of LDL-C, p = 0.008). On-treatment LDL and CRP concentrations both below the group median values were associated with the greatest likelihood of CIMT regression. CONCLUSIONS: Regression of carotid atherosclerosis is directly related to the absolute LDL-C level on statin therapy. The greatest regression was obtained with an LDL-C < 70 mg/dl, supporting marked LDL-C reduction to levels below current NCEP guidelines.

Meta-analysis of randomized clinical trials on the usefulness of acetylcysteine for prevention of contrast nephropathy.

Multiple small studies of oral N-acetylcysteine for prevention of contrast nephropathy have been performed, demonstrating variable efficacy. We performed a meta-analysis of the randomized clinical trials to clarify the degree of benefit.

Usefulness of lowering low-density lipoprotein cholesterol to <70 mg/dl and usefulness of C-reactive protein in patient selection.

C-reactive protein levels may identify patients likely to benefit from lowering low-density lipoprotein (LDL) cholesterol to ultra-low levels. We find that above-average C-reactive protein with statin therapy predicts failure of carotid intima-media thickness regression in those with currently defined optimal LDL cholesterol (<100 mg/dl) but not if LDL cholesterol is <70 mg/dl.

Effect of atorvastatin and pravastatin on serum C-reactive protein.

BACKGROUND: Extra-lipid effects of statins, such as anti-inflammatory actions, may contribute to their clinical benefit. These effects, with important implications for the concept of a statin "class effect," may be drug specific or may be related to the extent of lipid lowering. METHODS: We randomized 130 patients to treatment with either atorvastatin (80 mg daily, n = 63) or pravastatin (40 mg daily, n = 67), and measured serum lipids, C-reactive protein, and fibrinogen at baseline and after 3 months of therapy. RESULTS: Mean C-reactive protein (CRP) levels were significantly reduced in both groups, with a 36% reduction in the atorvastatin group (0.39 +/- 0.36 to 0.25 +/- 0.27, P =.001) and a 22% reduction observed in the pravastatin group (0.40 +/- 0.33 to 0.31 +/- 0.32, P =.003). A reduced or unchanged CRP level was seen in 67.2% of pravastatin-treated patients (45/67) and 73% of atorvastatin- treated patients (46/63) (P =.47). There was no difference between drugs in either the absolute or relative reductions in CRP levels. However, whereas the reduction of CRP with pravastatin was unrelated to the degree of low-density lipoprotein reduction (r = -.05, P =.69), atorvastatin-induced CRP reductions correlated directly to the change in low-density lipoprotein-C (r =.33, P =.009). CONCLUSIONS: High-dose atorvastatin and pravastatin both reduce CRP levels. However, whereas pravastatin's effect on CRP is independent of lipid-lowering efficacy, these data suggest that lipid-dependent mechanisms are, at least in part, active in atorvastatin-treated patients.

ARBITER: Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol: a randomized trial comparing the effects of atorvastatin and pravastatin on carotid intima medial thickness.

BACKGROUND: Whether marked LDL reduction to levels well below 100 mg/dL would further reduce the burden of cardiovascular disease is controversial. We compared the effects of 2 statins with widely differing potencies for LDL reduction (pravastatin 40 mg/d and atorvastatin 80 mg/d) on carotid intima-media thickness (CIMT). METHODS AND RESULTS: This was a single-center, randomized, clinical trial of 161 patients (mean age, 60 years; 71.4% male; 46% with known cardiovascular disease) that met National Cholesterol Education Program (NCEP) II criteria for lipid-lowering therapy. The effects of atorvastatin (80 mg/d; n=79) and pravastatin (40 mg/d; n=82) on CIMT were compared using blinded, serial assessments of the far wall of the distal common carotid artery. Baseline CIMT and other characteristics were similar between study groups. As anticipated, atorvastatin was substantially more potent for LDL reduction after 12 months: in the atorvastatin group, LDL cholesterol was 76+/-23 mg/dL after 12 months (-48.5%); LDL cholesterol was 110+/-30 mg/dL in the pravastatin group (-27.2%; P<0.001). Atorvastatin induced progressive CIMT regression over 12 months (change in CIMT, -0.034+/-0.021 mm), whereas CIMT was stable in the pravastatin group (change of 0.025+/- 0.017 mm; P=0.03). CONCLUSIONS: Marked LDL reduction (<100 mg/dL) with a high-potency statin provides superior efficacy for atherosclerosis regression at 1 year. This early effect on CIMT, a surrogate for clinical benefit, suggests that marked LDL reduction with synthetic statins may provide enhanced reduction in clinical coronary event rates.