The effects of continuous venovenous hemofiltration on coagulation activation

Introduction  

The mechanism of coagulation activation during continuous venovenous hemofiltration (CVVH) has not yet been elucidated. Insight into the mechanism(s) of hemostatic activation within the extracorporeal circuit could result in a more rational approach to anticoagulation. The aim of the present study was to investigate whether CVVH using cellulose triacetate filters causes activation of the contact factor pathway or of the tissue factor pathway of coagulation. In contrast to previous studies, CVVH was performed without anticoagulation.     

Awareness of eye complications and prevalence of retinopathy in the first visit to eye clinic among type 2 diabetic patients

AIM: To assess the awareness of eye complications and the prevalence of retinopathy, in the first visit to eye clinic, among type 2 diabetic patients attending a tertiary medical centre in Kuala Lumpur, Malaysia. METHODS: An investigator-administered questionnaire was given to 137 patients with diabetes undergoing first time eye screening in the eye clinic. This was followed by a detailed fundus examination by a senior ophthalmologist to assess for presence of retinopathy. RESULTS: Almost 86% of respondents were aware of diabetic eye complications, especially in patients who had achieved tertiary educational level (96.3%). The majority of the patients (78.8%) were referred by their physicians and only 20.4% came on their own initiative. Many of the patients (43.8%) did not know how frequent they should go for an eye check-up and 72.3% did not know what treatments were available. Lack of understanding on diabetic eye diseases (68.6%) was the main barrier for most patients for not coming for eye screening earlier. Despite a high level of awareness, only 21.9% had recorded HbA1c level of <6.5% while 31.4% were under the erroneous assumption of having a good blood sugar control. A total of 29.2% had diabetic retinopathy in their first visit eye testing. CONCLUSION: In the present study, 29.2% of type 2 diabetic patients had retinopathy in their first time eye testing. Although the awareness of diabetic eye complications was high among first time eye screening patients, the appropriate eye care-seeking behavior was comparatively less and should be rectified to prevent the rise of this sight threatening eye disease.     

An improved windowing technique for heart rate variability power spectrum estimation

Spectral analysis of heart rate variability (HRV) is an accepted method for assessment of cardiac autonomic function and its relationship to numerous disorders and diseases. Discrete Fourier transform (DFT) based methods are widely used for their easy applicability, computational speed and the possibility for direct interpretation of results. This study assesses the limitations of windowing of the RR interval series for power spectrum estimation using DFT for heart rate variability studies. The mean value of the RR interval series should be subtracted before windowing. This may leave a small residual DC component after windowing, but the RR interval series is properly tapered to zero at the beginning and end of the window. However, if the windowed RR interval series has a non-zero mean then subtracting this mean will create an abrupt transition between the first and last data points, and the padded zeros. This is equivalent to superimposing upon the RR interval series a rectangular pulse of the same length as the window, with a height equal to the subtracted mean value. In the present paper an approach to overcome the above effects of the window in reducing the signal energy and introducing low frequency components into the spectrum has been suggested and incorporated. Results have been compared for DC biasing of windowed data spectrum, bias of windowed data removed by subtraction of mean from data, and data preprocessed to remove windowed mean level and to maintain mean power. Thus the preprocessing of RR interval series with this method improves the accuracy of HRV analysis methods. The study was carried out by smoothing the complete RR interval series by single Hann window and by 50% overlapping the data segments of 256 data points followed by DFT. Overlapping the data segments provides equal weight to all values in the RR interval series and a smoothed spectral estimate with clearly dominant peaks in low- and high-frequency regions.