Browsing by Autor "Alejandro Pizano"

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Extrahepatic Biliary Tract Anatomy: A Review
(Wiley, 2020) Felipe Girón; Daniela Paola Ramírez-Buchheim; Alejandro Pizano; Roberto Javier Rueda‐Esteban
Laparoscopic cholecystectomy is one of the most common surgical procedures in general surgery. Significant gaps in knowledge still exist and even with clinical expertise, there might be limitations. Some of these are exploration restrictions during laparoscopic approach, visualization impairments and distortion of the usual arrangement of structures because of local inflammation, among others. Given the wide variability in anatomical presentation and considering that even in 56% of the population there is a close relationship to main vascular structures, intraoperative injuries might occur leading to higher rates of complications, longer surgical time and increased morbidity. Our aim is to describe the most common and relevant anatomic variations in the extrahepatic biliary tract (EBT). A systematic review of the literature was pursued using the MeSH terms: “Biliary Tract/abnormalities”, “Bile Ducts and Extrahepatic/abnormalities”. Only articles written in Spanish and English and limited to the last 20 years were considered. The anatomical structure considered normal for the EBT is described in roughly 60% of the population. The most variable structures according to included manuscripts are the left and right biliary ducts and the most prevalent variations are: posterior branch of the right hepatic duct draining into the left hepatic duct, triple confluence of the intrahepatic ducts, and anterior or posterior branch of the right hepatic duct draining into the common hepatic or cystic duct. As mentioned before the awareness and comprehension of EBT variations is crucial in avoiding complication, morbidity and achieving optimal outcomes in diagnostics and therapeutic procedures as reducing intraoperative iatrogenic injuries and considering the need of noninvasive techniques for EBT identification for a better surgical planning.
Ley matemática de los sistemas dinámicos cardiacos: reducción de su tiempo de evaluación a 18 horas
(National University of Córdoba, 2021) Javier Rodríguez; Sandra Catalina Correa Herrera; Alejandro Pizano; Miguel Ronderos; Signed Prieto; Carol Godoy; Juan Alexander Rojas; Juan de Dios Benítez; Dharma Rodríguez Correa; Eliana Avilán
It was confirmed the clinical capacity of the law to diagnose objectively and with reproducibility in 18 hours.
Ventilation‐perfusion ratio: A Mathematical Approach for Gas Exchange in the Lungs
(Wiley, 2019) Alejandro Pizano; Paola Calvacci; Felipe Girón; Juan Manuel Cordovez
Chronic pulmonary diseases and respiratory infections remained as one of the most morbid and deadliest diseases in the world. Airway and environment play an important role in the etiology of these pathologies. The balance between oxygen and carbon dioxide exchange is the pillar of the respiratory system. The ventilation ‐ perfusion ratio (VPR) determines the efficiency of gas exchange in different areas of the lung. For a long time the lung was assumed to be divided in three regions that would have homogenous VPR. Recently it was established that the VPR changes in a more heterogeneous fashion. The aim of this project is to understand the gas exchange in each alveoli using a mathematical model that produce the VPR architecture based on airways architecture. The model assumed mass balance, the ideal gas law and diffusional forces. Parameters for the model were determined according to data obtained in the literature and their correspondent mathematical calculus. The model was implemented in MATLAB (The MathWorks®, Inc.)and the equations were solved to steady state. The model predicted gas concentrations and flows in different lung segments. We were able to model healthy an pathological situations. In addition, we also simulated environmental influence in the small airways. The mathematical model was helpful to understand the gas exchange dynamics. It could be used to predict the interaction between ventilation and perfusion under different conditions, giving the possibility to estimate the efficacy of medical intervention. It can also shed some light on how to prevent anddecrease the incidence of lung diseases. Support or Funding Information Department of Biomedical Engineering, Universidad de los Andes, Bogota, Colombia This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .