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Advances in Surgery Sep 2023Prehospital resuscitation is a dynamic field now being energized by new technologies and a shift in thinking regarding intravascular resuscitation. Growing evidence... (Review)
Review
Prehospital resuscitation is a dynamic field now being energized by new technologies and a shift in thinking regarding intravascular resuscitation. Growing evidence discourages use of intravenous (IV) crystalloid and colloid solutions in trauma, whereas blood products, particularly whole blood, are becoming preferred. Although randomized clinical trials validating definitive resuscitative protocols are still lacking, most preclinical and clinical indicators support this approach. In addition, emerging technologies such as external and endovascular hemorrhage control devices and extracorporeal perfusion are now being used routinely, even in the prehospital setting in many countries, generating new lines of emerging investigations for trauma specialists.
Topics: Humans; Hemorrhage; Resuscitation; Perfusion; Crystalloid Solutions; Emergency Medical Services; Wounds and Injuries
PubMed: 37536856
DOI: 10.1016/j.yasu.2023.04.005 -
Magnetic Resonance Imaging Clinics of... Feb 2024Lung perfusion assessment is critical for diagnosing and monitoring a variety of respiratory conditions. MRI perfusion provides a radiation-free technique, making it an... (Review)
Review
Lung perfusion assessment is critical for diagnosing and monitoring a variety of respiratory conditions. MRI perfusion provides a radiation-free technique, making it an ideal choice for longitudinal imaging in younger populations. This review focuses on the techniques and applications of MRI perfusion, including contrast-enhanced (CE) MRI and non-CE methods such as arterial spin labeling (ASL), fourier decomposition (FD), and hyperpolarized 129-Xenon (129-Xe) MRI. ASL leverages endogenous water protons as tracers for a non-invasive measure of lung perfusion, while FD offers simultaneous measurements of lung perfusion and ventilation, enabling the generation of ventilation/perfusion mapsHyperpolarized 129-Xe MRI emerges as a novel tool for assessing regional gas exchange in the lungs. Despite the promise of MRI perfusion techniques, challenges persist, including competition with other imaging techniques and the need for additional validation and standardization. In conditions such as cystic fibrosis and lung cancer, MRI has displayed encouraging results, whereas in diseases like chronic obstructive pulmonary disease, further validation remains necessary. In conclusion, while MRI perfusion techniques hold immense potential for a comprehensive, non-invasive assessment of lung function and perfusion, their broader clinical adoption hinges on technological advancements, collaborative research, and rigorous validation.
Topics: Humans; Magnetic Resonance Imaging; Lung; Perfusion; Xenon Isotopes
PubMed: 38007274
DOI: 10.1016/j.mric.2023.09.006 -
Transplant International : Official... 2024
Topics: Humans; Liver Transplantation; Transplants; Perfusion; Organ Preservation; Graft Survival; Liver
PubMed: 38544563
DOI: 10.3389/ti.2024.12853 -
Magnetic Resonance Imaging Clinics of... Feb 2024Noninvasive imaging of tissue perfusion is a valuable tool for both research and clinical applications. Arterial spin labeling (ASL) is a contrast-free perfusion imaging... (Review)
Review
Noninvasive imaging of tissue perfusion is a valuable tool for both research and clinical applications. Arterial spin labeling (ASL) is a contrast-free perfusion imaging method that enables measuring and quantifying tissue blood flow using MR imaging. ASL uses radiofrequency and magnetic field gradient pulses to label arterial blood water, which then serves as an endogenous tracer. This review highlights the basic mechanism of ASL perfusion imaging, labeling strategies, and quantification. ASL has been widely used during the past 30 years for the study of normal brain function as well as in multiple neurovascular, neuro-oncological and degenerative pathologic conditions.
Topics: Humans; Magnetic Resonance Imaging; Spin Labels; Brain; Perfusion; Perfusion Imaging
PubMed: 38007283
DOI: 10.1016/j.mric.2023.08.005 -
Seminars in Respiratory and Critical... Oct 2023This article provides an overview of the journey of inspired oxygen after its uptake across the alveolar-capillary interface, and the interplay among tissue perfusion,...
This article provides an overview of the journey of inspired oxygen after its uptake across the alveolar-capillary interface, and the interplay among tissue perfusion, diffusion, and cellular respiration in the transport and utilization of oxygen. The critical interactions between oxygen and its facilitative carriers (hemoglobin in red blood cells and myoglobin in muscle cells), and with other respiratory and vasoactive molecules (carbon dioxide, nitric oxide, and carbon monoxide), are emphasized to illustrate how this versatile system dynamically optimizes regional convective transport and diffusive gas exchange. The rates of reciprocal gas exchange in the lung and the periphery must be well-matched and sufficient for meeting the range of energy demands from rest to maximal stress but not excessive as to become toxic. The mobile red blood cells play a vital role in matching tissue perfusion and gas exchange by dynamically regulating the controlled uptake of oxygen and communicating regional metabolic signals across different organs. Intracellular oxygen diffusion and facilitation via myoglobin into the mitochondria, and utilization via electron transport chain and oxidative phosphorylation, are summarized. Physiological and pathophysiological adaptations are briefly described. Dysfunction of any component across this integrated system affects all other components and elicits corresponding structural and functional adaptation aimed at matching the capacities across the entire system and restoring equilibrium under normal and pathological conditions.
Topics: Humans; Oxygen; Myoglobin; Lung; Cell Respiration; Perfusion; Oxygen Consumption
PubMed: 37541315
DOI: 10.1055/s-0043-1770061 -
Gastroenterology Clinics of North... Jun 2024Intestinal allotransplantation was first described in the 1960s and successfully performed in the 1980s. Since that time, less progress has been made in the preservation... (Review)
Review
Intestinal allotransplantation was first described in the 1960s and successfully performed in the 1980s. Since that time, less progress has been made in the preservation of the allograft before transplantation and static cold storage remains the current standard. Normothermic machine perfusion represents an opportunity to simultaneously preserve, assess, and recondition the organ for transplantation and improve the procurement radius for allografts. The substantial progress made in the field during the last 60 years, coupled with the success of the preclinical animal model of machine perfusion-preserved intestinal transplantation, suggest we are approaching the point of clinical application.
Topics: Organ Preservation; Humans; Intestines; Allografts; Animals; Perfusion; Transplantation, Homologous; Organ Preservation Solutions
PubMed: 38719374
DOI: 10.1016/j.gtc.2024.01.006 -
The Journal of Thoracic and... Feb 2024Cross-sectional imaging allows identification of rare patients with a vascular ring and circumflex aorta. The key diagnostic feature is crossing of the transverse aortic... (Review)
Review
OBJECTIVE
Cross-sectional imaging allows identification of rare patients with a vascular ring and circumflex aorta. The key diagnostic feature is crossing of the transverse aortic arch from right to left posterior to the trachea and superior to the carina in a patient with a right aortic arch. We evaluated our patients who received an aortic uncrossing procedure.
METHODS
We reviewed all patients who underwent aortic uncrossing from 2002 to 2022. All patients received preoperative computed tomography imaging and bronchoscopy.
RESULTS
Eleven patients ranging in age from 1.5 to 10 years (median 4 years) underwent aortic uncrossing. Two patients had prior left ligamentum division, and 3 patients had prior left aortic arch division. All had significant clinical symptoms. Eight patients had deep hypothermic circulatory arrest (mean 34 minutes), and 3 patients had antegrade cerebral perfusion (median, 28 minutes). Patch material was not used for aortic augmentation, and no patient underwent a posterior tracheopexy or rotational esophagoplasty. Postoperative length of stay ranged from 4 to 31 days (median, 5 days). One patient required a temporary tracheostomy for bilateral recurrent laryngeal nerve paresis, which recovered. One patient required an aortic extension graft to alleviate esophageal compression from an unusual ectatic esophageal course. All patients had relief of airway symptoms and dysphagia.
CONCLUSIONS
In properly selected patients with a right aortic arch and circumflex aorta, aortic uncrossing is a safe and effective therapy to treat airway and esophageal compression. The procedure can be conducted with deep hypothermic circulatory arrest or antegrade cerebral perfusion. Careful attention to the location of the esophagus and recurrent laryngeal nerves is required.
Topics: Humans; Infant; Child, Preschool; Child; Aorta; Aorta, Thoracic; Bronchoscopy; Vascular Surgical Procedures; Perfusion
PubMed: 37406764
DOI: 10.1016/j.jtcvs.2023.06.013 -
Transplantation Jan 2024Normothermic machine perfusion (NMP) aims to preserve organs ex vivo by simulating physiological conditions such as body temperature. Recent advancements in NMP system... (Review)
Review
Normothermic machine perfusion (NMP) aims to preserve organs ex vivo by simulating physiological conditions such as body temperature. Recent advancements in NMP system design have prompted the development of clinically effective devices for liver, heart, lung, and kidney transplantation that preserve organs for several hours/up to 1 d. In preclinical studies, adjustments to circuit structure, perfusate composition, and automatic supervision have extended perfusion times up to 1 wk of preservation. Emerging NMP platforms for ex vivo preservation of the pancreas, intestine, uterus, ovary, and vascularized composite allografts represent exciting prospects. Thus, NMP may become a valuable tool in transplantation and provide significant advantages to biomedical research. This review recaps recent NMP research, including discussions of devices in clinical trials, innovative preclinical systems for extended preservation, and platforms developed for other organs. We will also discuss NMP strategies using a global approach while focusing on technical specifications and preservation times.
Topics: Female; Humans; Organ Preservation; Kidney Transplantation; Liver; Perfusion; Liver Transplantation
PubMed: 37026713
DOI: 10.1097/TP.0000000000004573 -
Transplantation Mar 2024Despite the increased usage of livers from donation after circulatory death (DCD) donors in the last decade, many patients remaining on the waitlist who need a liver... (Review)
Review
Despite the increased usage of livers from donation after circulatory death (DCD) donors in the last decade, many patients remaining on the waitlist who need a liver transplant. Recent efforts have focused on maximizing the utilization and outcomes of these allografts using advances in machine perfusion technology and other perioperative strategies such as normothermic regional perfusion (NRP). In addition to the standard donor and recipient matching that is required with DCD donation, new data regarding the impact of graft steatosis, extensive European experience with NRP, and the increasing use of normothermic and hypothermic machine perfusion have shown immense potential in increasing DCD organ overall utilization and improved outcomes. These techniques, along with viability testing of extended criteria donors, have generated early promising data to consider the use of higher-risk donor organs and more widespread adoption of these techniques in the United States. This review explores the most recent international literature regarding strategies to optimize the utilization and outcomes of DCD liver allografts, including donor-recipient matching, perioperative strategies including NRP versus rapid controlled DCD recovery, viability assessment of discarded livers, and postoperative strategies including machine perfusion versus pharmacologic interventions.
Topics: Humans; United States; Organ Preservation; Tissue Donors; Perfusion; Liver; Liver Transplantation; Graft Survival; Tissue and Organ Procurement; Death
PubMed: 37496117
DOI: 10.1097/TP.0000000000004739 -
Nature Communications Aug 2023Current machine perfusion technology permits livers to be preserved ex situ for short periods to assess viability prior to transplant. Long-term normothermic perfusion...
Current machine perfusion technology permits livers to be preserved ex situ for short periods to assess viability prior to transplant. Long-term normothermic perfusion of livers is an emerging field with tremendous potential for the assessment, recovery, and modification of organs. In this study, we aimed to develop a long-term model of ex situ perfusion including a surgical split and simultaneous perfusion of both partial organs. Human livers declined for transplantation were perfused using a red blood cell-based perfusate under normothermic conditions (36 °C) and then split and simultaneously perfused on separate machines. Ten human livers were split, resulting in 20 partial livers. The median ex situ viability was 125 h, and the median ex situ survival was 165 h. Long-term survival was demonstrated by lactate clearance, bile production, Factor-V production, and storage of adenosine triphosphate. Here, we report the long-term ex situ perfusion of human livers and demonstrate the ability to split and perfuse these organs using a standardised protocol.
Topics: Humans; Liver Transplantation; Liver; Perfusion; Bile; Preservation, Biological
PubMed: 37553343
DOI: 10.1038/s41467-023-40154-8