Iterative method to obtain semi-circle variables from bioimpedance measurements for Cole's Modeling.

Bioimpedance Spectroscopy measurements and Cole-Cole models are commonly used to characterize biological systems. Cole-Cole model parameters may be obtained by fitting the measured bioimpedance data into a semicircle. This work proposes an iterative method to approximate a bioimpedance dataset to a Cole-Cole model analysis using only three points. The performance of the proposed method was compared against similar methods reported in a recent publication; our proposal presents greater efficiency (87.5%) and lower mean error (0.022) than the compared methods. The main contribution of the proposed method is that its performance does not rely on the user's technical knowledge, neither does it on the instrument used to perform the measurements, while the compared methods do.Clinical Relevance- Our proposal is an efficient unsupervised iterative method to acquire the clinically-relevant parameters from a Cole-Cole analysis from a given bioimpedance spectroscopy dataset, eliminating the need for the user to have prior technical knowledge on bioimpedance, thus, furthering the use of bioimpedance technology in the clinical point-of-care.

Possible Assessment of Calf Venous Pump Efficiency by Computational Fluid Dynamics Approach.

Three-dimensional simulations of peripheral, deep venous flow during muscular exercise in limbs of healthy subjects and in those with venous dysfunction were carried out by a computational fluid-dynamics (CFD) approach using the STAR CCM + platform. The aim was to assess the effects of valvular incompetence on the venous calf pump efficiency. The model idealizes the lower limb circulation by a single artery, a capillary bed represented by a porous region and a single vein. The focus is on a segment of the circuit which mimics a typical deep vein at the level of the calf muscle, such as the right posterior tibial vein. Valves are idealized as ball valves, and periodic muscle contractions are given by imposing time-dependent boundary conditions to the calf segment wall. Flow measurements were performed in two cross-sections downstream and upstream of the calf pump. Model results demonstrate a reduced venous return for incompetent valves during calf exercise. Two different degrees of valvular incompetence are considered, by restricting the motion of one or both valves. Model results showed that only the proximal valve is critical, with a 30% reduction of venous return during calf exercise in case of valvular incompetence: the net flow volume ejected by the calf in central direction was 0.14 mL per working cycle, against 0.2 mL for simulated healthy limbs. This finding appeared to be consistent with a 25% reduction of the calf ejection fraction, experimentally observed in chronic venous disease limbs compared with healthy limbs.

Left colon obstruction due to non-reducible Spigelian hernia of the right side. Report of a case and literature review.

AIM: Describe a rare case of intestinal obstruction due to sigmoid colon incarceration into a right Spigelian hernia and provide a literature review about its surgical management. MATERIAL OF STUDY: An 88 year-old man presented with a 3-day history of right lower quadrant pain and abdominal distension. Clinical examination revealed a not reducible palpable mass on right side of the anterior abdominal wall. Computed tomography shown signs of intestinal obstruction and a Spigelian hernia of about 3 cm. RESULTS: Sigmoid colon was incarcerated in the defect but no signs of intestinal ischemia was found during the surgical exploration. The hernia content was reduced and the defect was repaired with a polypropylene mesh placed in the pre-peritoneal space. Postoperative period was uneventful and the patient was discharged on the fourth postoperative day. DISCUSSION: Spigelian hernia occurs through congenital or acquired defects in the Spigelian fascia at the level of the semicircular line. Clinical presentation depends on the size and the pattern of the hernia defect. In some cases, symptoms are no specific and uncommon findings have been reported so far. Preoperative establishment of the hernia content and the location of the sac is mandatory to plan a correct surgical strategy. Intestinal incarceration often occurs and suggests a prompt surgical exploration. CONCLUSIONS: Colonic obstruction secondary to an incarcerated Spigelian hernia is a rare but dangerous occurrence. Surgical approach is selected based on patient's conditions and surgeon's expertise. In a non-contaminated surgical field, the use of prosthesis is recommended. KEY WORDS: Intestinal obstruction, Mesh repair, Spigelian hernia.