Artificial kidney: Challenges and opportunities

This review aims to present the developments occurring in the field of artificial organs and particularly focuses on the presentation of developments in artificial kidneys.The challenges for biomedical engineering involved in overcoming the potential difficulties are showcased,as well as the importance of interdisciplinary collaboration in this marriage of medicine and technology.In this review,modern artificial kidneys and the research efforts trying to provide and promise artificial kidneys are presented.But what are the problems faced by each technology and to what extent is the effort enough to date?

Critical considerations for the management of acute abdomen in transplant patients

The number of solid organ transplantations performed annually is increasing and are increasing in the following order:Kidney,liver,heart,lung,pancreas,small bowel,and uterine transplants.However,the outcomes of transplants are impro-ving(organ survival>90%after the 1st year).Therefore,there is a high probability that a general surgeon will be faced with the management of a transplant patient with acute abdomen.Surgical problems in immunocompromised patients may not only include graft-related problems but also nongraft-related problems.The perioperative regulation of immunosuppression,the treatment of accompanying problems of immunosuppression,the administration of cortisol and,above all,the realization of a rapidly deteriorating situation and the accurate evaluation and interpretation of clinical manifestations are particularly important in these patients.The perioperative assessment and preparation includes evaluation of the patient’s cardiovascular system and determining if the patient has hypertension or suppression of the hypothalamic-pituitary-adrenal axis,or if the patient has had any coagulation mechanism abnormalities or thromboembolic episodes.Immunosuppression in transplant patients is associated with the use of calci-neurin inhibitors,corticosteroids,and antiproliferation agents.Many times,the clinical picture is atypical,resulting in delays in diagnosis and treatment and leading to increased morbidity and mortality.Multidetector computed tomo-graphy is of utmost importance for early diagnosis and management.Transplant recipients are prone to infections,especially specific infections caused by cytomegalovirus and Clostridium difficile,and they are predisposed to intraop-erative or postoperative complications that require great care and vigilance.It is necessary to follow evidence-based therapeutic protocols.Thus,it is required that the clinician choose the correct therapeutic plan for the patient(conservative,emergency open surgery or minimally invasive surgery,including laparoscopic or even robotic surgery).

Hepatic ischemia-reperfusion syndrome and its effect on the cardiovascular system: The role of treprostinil, a synthetic prostacyclin analog

Hepatic ischemia-reperfusion syndrome has been the subject of intensive study and experimentation in recent decades since it is responsible for the outcome of several clinical entities,such as major hepatic resections and liver transplantation.In addition to the organ’s post reperfusion injury,this syndrome appears to play a central role in the dysfunction of distant tissues and systems.Thus,continuous research should be directed toward finding effective therapeutic options to improve the outcome and reduce the postoperative morbidity and mortality rates.Treprostinil is a synthetic analog of prostaglandin I2,and its experimental administration has shown encouraging results.It has already been approved by the Food and Drug Administration in the United States for pulmonary arterial hypertension and has been used in liver transplantation,where preliminary encouraging results showed its safety and feasibility by using continuous intravenous administration at a dose of 5 ng/kg/min.Treprostinil improves renal and hepatic function,diminishes hepatic oxidative stress and lipid peroxidation,reduces hepatictoll-like receptor 9 and inflammation,inhibits hepatic apoptosis and restores hepatic adenosine triphosphate(ATP)levels and ATP synthases,which is necessary for functional maintenance of mitochondria.Treprostinil exhibits vasodilatory properties and antiplatelet activity and regulates proinflam-matory cytokines;therefore,it can potentially minimize ischemia-reperfusion injury.Additionally,it may have beneficial effects on cardiovascular parameters,and much current research interest is concentrated on this compound.

Enhanced recovery after surgery in liver transplantation:Challenges and feasibility

BACKGROUND Enhanced recovery after surgery(ERAS)started a revolution that changed age-old surgical stereotypical practices regarding the overall management of the surgical patient.In the last decade,ERAS has gained significant acceptance in the community of general surgery,in addition to several other surgical specialties,as the evidence of its advantages continues to grow.One of the last remaining fields,given its significant complexity and intricate nature,is liver transplantation(LT).AIM To investigate the existing efforts at implementing ERAS in LT.METHODS We conducted a systematic review of the existing studies that evaluate ERAS in orthotopic LT,with a multimodal approach and focusing on measurable clinical primary endpoints,namely length of hospital stay.RESULTS All studies demonstrated a considerable decrease in length of hospital stay,with no readmission or negative impact of the ERAS protocol applied to the postoperative course.CONCLUSIONS ERAS is a well-validated multimodal approach for almost all types of surgical procedures,and its future in selected LT patients seems promising,as the preliminary results advocate for the safety and efficacy of ERAS in the field of LT.

Surgical chest complications after liver transplantation

Liver transplantation is a major abdominal operation and the intimate anatomic relation of the liver with the right hemidiaphragm predisposes the patient to various manifestations in the chest cavity.Furthermore,chronic liver disease affects pulmonary function before and after liver transplantation resulting in a considerable percentage of patients presenting with morbidity related to chest complications.This review aims to identify the potential chest complications of surgical interest during or after liver transplantation.Complications of surgical interest are defined as those conditions that necessitate an invasive procedure(such as thoracocentesis or a chest tube placement)in the chest or a surgical intervention performed by a thoracic surgeon.These complications will be classified as perioperative and postoperative;the latter will be categorized as early and late.Although thoracocentesis or a chest tube placement is usually sufficient when invasive measures are deemed necessary,in some patients,thoracic surgical interventions are warranted.A high index of suspicion is needed to recognize and treat these conditions promptly.A close collaboration between abdominal surgeons,intensive care unit physicians and thoracic surgeons is of paramount importance.

Volumetric assessment of hepatic grafts using a light detection and ranging system for 3D scanning:Preliminary data

BACKGROUND Liver transplantation has evolved into a safe life-saving operation and remains the golden standard in the treatment of end stage liver disease.The main limiting factor in the application of liver transplantation is graft shortage.Many strategies have been developed in order to alleviate graft shortage,such as living donor partial liver transplantation and split liver transplantation for adult and pediatric patients.In these strategies,liver volume assessment is of paramount importance,as size mismatch can have severe consequences in the success of liver transplantation.AIM To evaluate the safety,feasibility,and accuracy of light detection and ranging(LIDAR)3D photography in the prediction of whole liver graft volume and mass.METHODS Seven liver grafts procured for orthotopic liver transplantation from brain deceased donors were prospectively measured with an LIDAR handheld camera and their mass was calculated and compared to their actual weight.RESULTS The mean error of all measurements was 17.03 g(range 3.56-59.33 g).Statistical analysis of the data yielded a Pearson correlation coefficient index of 0.9968,indicating a strong correlation between the values and a Student’s t-test P value of 0.26.Mean accuracy of the measurements was calculated at 97.88%.CONCLUSION Our preliminary data indicate that LIDAR scanning of liver grafts is a safe,cost-effective,and feasible method of ex vivo determination of whole liver volume and mass.More data are needed to determine the precision and accuracy of this method.

Effects of an active lifestyle on the physical frailty of liver transplant candidates

BACKGROUND Liver transplantation is the most important therapeutic intervention for end-stage liver disease(ELD).The prioritization of these patients is based on the model for end-stage liver disease(MELD),which can successfully predict short-term mortality.However,despite its great validity and value,it cannot fully incorporate several comorbidities of liver disease,such as sarcopenia and physical frailty,variables that can sufficiently influence the survival of such patients.Subsequently,there is growing interest in the importance of physical frailty in regard to mortality in liver transplant candidates and recipients,as well as its role in improving their survival rates.AIM To evaluate the effects of an active lifestyle on physical frailty on liver transplant candidates.METHODS An observational study was performed within the facilities of the Department of Transplant Surgery of Aristotle University of Thessaloniki.Twenty liver transplant candidate patients from the waiting list of the department were included in the study.Patients that were bedridden,had recent cardiovascular incidents,or had required inpatient treatment for more than 5 d in the last 6 mo were excluded from the study.The following variables were evaluated:Activity level via the International Physical Activity Questionnaire(IPAQ);functional capacity via the 6-min walking test(6MWT)and cardiopulmonary exercise testing;and physical frailty via the Liver Frailty Index(LFI).RESULTS According to their responses in the IPAQ,patients were divided into the following two groups based on their activity level:Active group(A,10 patients);and sedentary group(S,10 patients).Comparing mean values of the recorded variables showed the following results:MELD(A:12.05±5.63 vs S:13.99±3.60;P>0.05);peak oxygen uptake(A:29.78±6.07 mL/kg/min vs S:18.11±3.39 mL/kg/min;P<0.001);anaerobic threshold(A:16.71±2.17 mL/kg/min vs S:13.96±1.45 mL/kg/min;P<0.01);6MWT(A:458.2±57.5 m vs S:324.7±55.8 m;P<0.001);and LFI(A:3.75±0.31 vs S:4.42±0.32;P<0.001).CONCLUSION An active lifestyle can be associated with better musculoskeletal and functional capacity,while simultaneously preventing the evolution of physical frailty in liver transplant candidates.This effect appears to be independent of the liver disease severity.