We have developed a real-time algorithm for detection of the QRS complexes of ECG signals. It reliably recognizes QRS complexes based upon digital analyses of slope, amplitude, and width. A special digital bandpass filter reduces false detections caused by the various types of interference present in ECG signals. This filtering permits use of low thresholds, thereby increasing detection sensitivity. The algorithm automatically adjusts thresholds and parameters periodically to adapt to such ECG changes as QRS morphology and heart rate. For the standard 24 h MIT/BIH arrhythmia database, this algorithm correctly detects 99.3 percent of the QRS complexes.

/pdf/a-real-time-qrs-detection-algorithm-5dqh3i09n2.pdf

A Real-Time QRS Detection Algorithm

K/DOQI clinical practice guidelines for cardiovascular disease in dialysis patients.

De Lorenzo, A., A. Andreoli, J. Matthie, and P. Withers.Predicting body cell mass with bioimpedance by using theoretical methods: a technological review. J. Appl. Physiol. 82(5): 1542–1558, 1997.—T...

Predicting body cell mass with bioimpedance by using theoretical methods: a technological review

https://www.kidney-international.org/article/S0085-2538(15)58586-4/pdf

A new method for monitoring body fluid variation by bioimpedance analysis: The RXc graph

Cytokines play a crucial role in the modulation of inflammatory response in the gastrointestinal tract. Pro-inflammatory cytokines including tumor necrosis factor-alpha, interferon-gamma, interleukin-1beta?IL-1beta?, and interleukin-12 are essential in mediating the inflammatory response, while anti-inflammatory cytokines including interleukin-10 and transforming growth factor-beta are important in the attenuation or containment of inflammatory process. It is increasingly recognized that cytokines have an important physiological and pathological effect on intestinal tight junction (TJ) barrier. Consistent with their known pro-inflammatory activities, pro-inflammatory cytokines cause a disturbance in intestinal TJ barrier, allowing increased tissue penetration of luminal antigens. Recent studies indicate that the inhibition of cytokine induced increase in intestinal TJ permeability has an important protective effect against intestinal mucosal damage and development of intestinal inflammation. In this review, the effects of various pro-inflammatory and anti-inflammatory cytokines on intestinal TJ barrier and the progress into the mechanisms that mediate the cytokine modulation of intestinal TJ barrier are reviewed.

/pdf/mechanism-of-cytokine-modulation-of-epithelial-tight-3x1numui0v.pdf

Mechanism of cytokine modulation of epithelial tight junction barrier.

https://www.kidney-international.org/article/S0085-2538(15)57490-5/pdf

Assessment of post-dialysis dry weight: An application of the conductivity measurement method

A method to measure intra- and extracellular conductivity is evaluated. In vitro experiments show that these two variables can be measured separately. The conductivity appears to depend on the concentration and fluid volume of the compartment concerned. In vitro variation of the intracellular volume of blood by dilution and by shrinking and swelling of blood cells is detectable by this method. In vivo too the method seems to detect intra- and extracellular fluid volumes separately. The course of these two variables during different strategies of haemodialysis is determined.

Measurement of transcellular fluid shift during haemodialysis. Part 2. In vitro and clinical evaluation.

In this study it is demonstrated that, for defibrillation with a rectangular pulse, the relationship between threshold current strength and pulse width can be approximated by a hyperbola. Also the threshold charge and energy required for effective defibrillation are presented as functions of the pulse duration. From these three curves it can be seen that, for a rectangular pulse, the current strength is minimal for a duration between 20 and 40 ms, the charge, for a ‘zero’ duration and the energy for a duration of around 4 ms. Myocardial performance is generally assumed to be, minimally disturbed after a defibrillation shock if the applied current, charge and energy of one pulse are all minimal. Then it can be concluded that, for a rectangular pulse, no duration can be advised for defibrillation with the least myocardial disturbance after the shock, since current, charge, and energy have their minimums at different, pulse durations.

Amplitude-duration relation for direct ventricular defibrillation with rectangular current pulses.

Susceptibility to decubitus ulcer formation

One of the main causes of hypotension during extracorporeal renal replacement therapy is an insufficient substitution of the ultrafiltrated plasma water by tissue water. To investigate the fluid balance and its effects on hypotension in dialysed patients, the following variables were studied: intracellular fluid volume (IFV) and extracellular fluid volume (EFV), blood volume (BV) and blood pressure. IFV and EFV were measured by means of non-invasive electrical conductivity measurements using four electrodes round the leg. Fifteen haemofiltration (HF) and 15 haemodialysis (HD) patients were studied. The latter group was dialysed in three ways: (1) conventionally, i.e. with dialysate sodium of 138 mmol/l (HD) (2) with a variable dialysate sodium (first half: 138 mmol/l; second half: 146 mmol/l) (HDS), and (3) with the same variable dialysate sodium and an ultrafiltration profile (two-thirds was withdrawn during the first half of treatment, the remainder during the second half) (HDSU). Hypotension frequency was less during HDS, HDSU, and HF compared to HD. This was caused by a more stable blood volume due to a better refill. During HD a fluid shift occurred from the EC to the IC compartment. The use of a high sodium dialysate concentration led to a transcellular fluid shift in the opposite direction. This fluid shift increased the refill, thereby stabilising blood volume. HF gave a better refill than HDS and HDSU, probably due to a reduced urea clearance.

H. Schneider

Papers

Assessment of post-dialysis dry weight: An application of the conductivity measurement method

Measurement of transcellular fluid shift during haemodialysis. Part 2. In vitro and clinical evaluation.

Amplitude-duration relation for direct ventricular defibrillation with rectangular current pulses.

Susceptibility to decubitus ulcer formation

Fluid Balance During Haemodialysis and Haemofiltration: The Effect of Dialysate Sodium and a Variable Ultrafiltration Rate