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Seminars in Respiratory and Critical... Oct 2023The pulmonary circulation is a low-pressure, low-resistance circuit whose primary function is to deliver deoxygenated blood to, and oxygenated blood from, the pulmonary... (Review)
Review
The pulmonary circulation is a low-pressure, low-resistance circuit whose primary function is to deliver deoxygenated blood to, and oxygenated blood from, the pulmonary capillary bed enabling gas exchange. The distribution of pulmonary blood flow is regulated by several factors including effects of vascular branching structure, large-scale forces related to gravity, and finer scale factors related to local control. Hypoxic pulmonary vasoconstriction is one such important regulatory mechanism. In the face of local hypoxia, vascular smooth muscle constriction of precapillary arterioles increases local resistance by up to 250%. This has the effect of diverting blood toward better oxygenated regions of the lung and optimizing ventilation-perfusion matching. However, in the face of global hypoxia, the net effect is an increase in pulmonary arterial pressure and vascular resistance. Pulmonary vascular resistance describes the flow-resistive properties of the pulmonary circulation and arises from both precapillary and postcapillary resistances. The pulmonary circulation is also distensible in response to an increase in transmural pressure and this distention, in addition to recruitment, moderates pulmonary arterial pressure and vascular resistance. This article reviews the physiology of the pulmonary vasculature and briefly discusses how this physiology is altered by common circumstances.
Topics: Humans; Vasoconstriction; Vascular Resistance; Lung; Pulmonary Circulation; Hypoxia; Blood Pressure
PubMed: 37816344
DOI: 10.1055/s-0043-1770059 -
European Heart Journal Aug 2023The current treatment algorithm for chronic thromboembolic pulmonary hypertension (CTEPH) as depicted in the 2022 European Society of Cardiology (ESC)/European...
Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: a clinical consensus statement of the ESC working group on pulmonary circulation and right ventricular function.
The current treatment algorithm for chronic thromboembolic pulmonary hypertension (CTEPH) as depicted in the 2022 European Society of Cardiology (ESC)/European Respiratory Society (ERS) guidelines on the diagnosis and treatment of pulmonary hypertension (PH) includes a multimodal approach of combinations of pulmonary endarterectomy (PEA), balloon pulmonary angioplasty (BPA) and medical therapies to target major vessel pulmonary vascular lesions, and microvasculopathy. Today, BPA of >1700 patients has been reported in the literature from centers in Asia, the US, and also Europe; many more patients have been treated outside literature reports. As BPA becomes part of routine care of patients with CTEPH, benchmarks for safe and effective care delivery become increasingly important. In light of this development, the ESC Working Group on Pulmonary Circulation and Right Ventricular Function has decided to publish a document that helps standardize BPA to meet the need of uniformity in patient selection, procedural planning, technical approach, materials and devices, treatment goals, complications including their management, and patient follow-up, thus complementing the guidelines. Delphi methodology was utilized for statements that were not evidence based. First, an anatomical nomenclature and a description of vascular lesions are provided. Second, treatment goals and definitions of complete BPA are outlined. Third, definitions of complications are presented which may be the basis for a standardized reporting in studies involving BPA. The document is intended to serve as a companion to the official ESC/ERS guidelines.
Topics: Humans; Hypertension, Pulmonary; Pulmonary Embolism; Pulmonary Circulation; Ventricular Function, Right; Angioplasty, Balloon; Pulmonary Artery; Chronic Disease; Cardiology
PubMed: 37470202
DOI: 10.1093/eurheartj/ehad413 -
Anesthesiology Mar 2024Extracorporeal Circulation in Neonatal Respiratory Failure: A Prospective Randomized Study. By RH Bartlett, DW Roloff, RG Cornell, AF Andrews, PW Dillon, JB... (Review)
Review
Extracorporeal Circulation in Neonatal Respiratory Failure: A Prospective Randomized Study. By RH Bartlett, DW Roloff, RG Cornell, AF Andrews, PW Dillon, JB Zwischenberger. Pediatrics 1985; 76:479-87. Extracorporeal membrane oxygenation (ECMO) is the use of mechanical devices to replace cardiac and pulmonary function in critical care. In the 1960s, laboratory research showed that extracorporeal circulation could be maintained for days using a membrane oxygenator. In the 1970s, the first clinical trials showed that ECMO could sustain life in severe cardiac and pulmonary failure for days or weeks, leading to organ recovery. From 1980 to 2000, ECMO became standard practice for neonatal and pediatric respiratory and cardiac failure. The critical clinical trial was a prospective randomized trial of ECMO in newborn respiratory failure, published in 1985. This is the classic article reviewed in this publication. This was the first use of a randomized, adaptive design trial to minimize the potential ethical dilemma inherent to clinical trials in which the endpoint is death. Other randomized trials followed, and ECMO is now standard practice for severe respiratory and cardiac failure in all age groups.
Topics: Infant, Newborn; Humans; Child; Extracorporeal Membrane Oxygenation; Prospective Studies; Heart; Heart Failure; Respiratory Insufficiency; Randomized Controlled Trials as Topic
PubMed: 38349754
DOI: 10.1097/ALN.0000000000004843 -
European Heart Journal Nov 2023Acute heart failure (AHF) represents the most frequent cause of unplanned hospital admission in patients older than 65 years. Symptoms and clinical signs of AHF (e.g....
Acute heart failure (AHF) represents the most frequent cause of unplanned hospital admission in patients older than 65 years. Symptoms and clinical signs of AHF (e.g. dyspnoea, orthopnoea, oedema, jugular vein distension, and variation of body weight) are mostly related to systemic venous congestion secondary to various mechanisms including extracellular fluids, increased ventricular filling pressures, and/or auto-transfusion of blood from the splanchnic into the pulmonary circulation. Thus, the initial management of AHF patients should be mostly based on decongestive therapies on admission followed, before discharge, by rapid implementation of guideline-directed oral medical therapies for heart failure. The therapeutic management of AHF requires the identification and rapid diagnosis of the disease, the diagnosis of the cause (or triggering factor), the evaluation of severity, the presence of comorbidities, and, finally, the initiation of a rapid treatment. The most recent guidelines from ESC and ACC/AHA/HFSA have provided updated recommendations on AHF management. Recommended pharmacological treatment for AHF includes diuretic therapy aiming to relieve congestion and achieve optimal fluid status, early and rapid initiation of oral therapies before discharge combined with a close follow-up. Non-pharmacological AHF management requires risk stratification in the emergency department and non-invasive ventilation in case of respiratory failure. Vasodilators should be considered as initial therapy in AHF precipitated by hypertension. On the background of recent large randomized clinical trials and international guidelines, this state-of-the-art review describes current pharmacological treatments and potential directions for future research in AHF.
Topics: Humans; Acute Disease; Heart Failure; Edema; Hospitalization; Patient Discharge; Dyspnea
PubMed: 37850661
DOI: 10.1093/eurheartj/ehad617