ventilation-perfusion

Background: The use of the prone position (PP) has been widespread during the COVID-19 pandemic. While it has demonstrated benefits, including improved oxygenation and lung aeration, the factors influencing the response in terms of gas exchange to PP remain unclear. In particular, the association between baseline quantitative Computed Tomography (qCT) scan results and gas exchange response to PP in intubated, mechanically ventilated subjects with COVID-19 ARDS is unknown. The present study aimed to compare baseline qCT results between subjects responding to PP in terms of oxygenation or carbon dioxide (CO2 ) clearance and those who did not...

AIM: The aim of this study is to investigate whether computer-aided, semi-automated 3D lung lobe quantification can support decision-making on PE diagnosis based on the ventilation-perfusion ratio in clinical practice. METHODS: A study cohort of 100 patients (39 male, 61 female, age 64.8±15.8 years) underwent ventilation/perfusion single photon emission computed tomography (V/Q-SPECT/CT) to exclude acute PE on SPECT/CT OPTIMA NM/CT 640 (GE Healthcare). Two 3D lung lobe quantification software tools (Q...

A very low incidence of acute kidney injury (AKI) has been observed in COVID-19 patients purposefully treated with early pressure support ventilation (PSV) compared to those receiving mainly controlled ventilation. The prevention of subdiaphragmatic venous congestion through limited fluid intake and the lowering of intrathoracic pressure is a possible and attractive explanation for this observed phenomenon. Both venous congestion, or "venous bagging", and a positive fluid balance correlate with the occurrence of AKI...

Purpose To assess the feasibility of monitoring the effects of elexacaftor-tezacaftor-ivacaftor (ETI) therapy on lung ventilation and perfusion in people with cystic fibrosis (CF), using phase-resolved functional lung (PREFUL) MRI. Materials and Methods This secondary analysis of a multicenter prospective study was carried out between August 2020 and March 2021 and included participants 12 years or older with CF who underwent PREFUL MRI, spirometry, sweat chloride test, and lung clearance index assessment before and 8-16 weeks after ETI therapy...

Due to its ability to induce heterogenous, patient-specific damage in pulmonary alveoli and capillaries, COVID-19 poses challenges in defining a uniform profile to elucidate infection across all patients. Computational models that integrate changes in ventilation and perfusion with heterogeneous damage profiles offer valuable insights into the impact of COVID-19 on pulmonary health. This study aims to develop an in silico hypothesis-testing platform specifically focused on studying microvascular pulmonary perfusion in COVID-19-infected lungs...

BACKGROUND: Single-photon emission computed tomography (SPECT) ventilation perfusion imaging is the main imaging method for the diagnosis of pulmonary embolism, and its application in the diagnosis and efficacy evaluation of chronic thromboembolic pulmonary hypertension (CTEPH) has been paid more and more attention. In recent years, with the development of computer software technology, ventilation/perfusion (V/Q) imaging quantitative analysis technology has become more and more mature...

In survivors of acute pulmonary embolism (PE), the post-PE syndrome (PPES) may occur. In PPES, patients typically present with persisting or progressive dyspnea on exertion despite 3 months of therapeutic anticoagulation. Therefore, a structured follow-up is warranted to identify patients with chronic thromboembolic pulmonary disease (CTEPD) with normal pulmonary pressure or chronic thromboembolic pulmonary hypertension (CTEPH). Both are currently understood as a dual vasculopathy, that is, secondary arterio- and arteriolopathy, affecting the large and medium-sized pulmonary arteries as well as the peripheral vessels (diameter < 50 µm)...

RATIONALE: Blood flow rate affects mixed venous oxygenation (SvO2 ) during venovenous extracorporeal membrane oxygenation (ECMO), with possible effects on the pulmonary circulation and the right heart function. OBJECTIVES: We aimed at describing the physiologic effects of different levels of SvO2 obtained by changing ECMO blood flow, in patients with severe ARDS receiving ECMO and controlled mechanical ventilation. METHODS: Low (SvO2 target 70-75%), intermediate (SvO2 target 75-80%) and high (SvO2 target > 80%) ECMO blood flows were applied for 30 minutes in random order in 20 patients...

BACKGROUND: Computed tomography pulmonary angiogram and lung scintigraphy with ventilation/perfusion scan are needed to diagnose pulmonary embolism (PE) in pregnancy. Their associated ionizing radiation doses are considered safe in pregnancy. A standardized patient information tool may improve patient counseling and reduce testing hesitancy. OBJECTIVES: In this context, we sought to address 1) what patients want to know before undergoing these tests and 2) how they want the information to be provided to them...

OBJECTIVES: We hypothesized that caffeine would be associated with a transient reduction in the right-to-left shunt and VA /Q. We aimed to explore the temporal effects of caffeine on right-to-left shunt, ventilation perfusion ratio (VA /Q) and shift of the oxyhaemoglobin dissociation curve (ODC) in premature ventilated infants. METHODS: Retrospective cohort study at a tertiary neonatal unit of infants born at less than 31 weeks of gestation that were mechanically ventilated on day three of life...

PURPOSE: The aim of this study was to assess the diagnostic performance of perfusion-only SPECT/CT (Q SPECT/CT) in comparison with that of ventilation/perfusion planar scintigraphy (V/Q planar), perfusion SPECT with ventilation scan (V/Q SPECT), and perfusion SPECT/CT with ventilation scan (V/Q SPECT/CT) in chronic thromboembolic pulmonary hypertension (CTEPH). PATIENTS AND METHODS: Patients with pulmonary hypertension who underwent ventilation-perfusion planar and SPECT/CT were retrospectively recruited...

KEY CLINICAL MESSAGE: Before valvular interventions, echocardiography, especially the TEE or the ventilation/perfusion scan, should be performed to detect silent PTE and set a more accurate treatment and surgical plan. ABSTRACT: Pulmonary hypertension (PH) is a progressive and critical disease that can be caused by mitral stenosis (MS). Some of these patients present with disproportionate PH, which is an uncommon phenomenon and is considered a challenging diagnostic and treatment process...

BACKGROUND: Measuring arterial partial pressure of carbon dioxide (PaCO2 ) is crucial for proper mechanical ventilation, but the current sampling method is invasive. End-tidal carbon dioxide (EtCO2 ) has been used as a surrogate, which can be measured non-invasively, but its limited accuracy is due to ventilation-perfusion mismatch. This study aimed to develop a non-invasive PaCO2 estimation model using machine learning. METHODS: This retrospective observational study included pediatric patients (< 18 years) admitted to the pediatric intensive care unit of a tertiary children's hospital and received mechanical ventilation between January 2021 and June 2022...

BACKGROUND: The risk of venous thromboembolism (VTE) is increased postpartum and contributes to important morbidity and mortality. While there have been advances in evaluating diagnostic algorithms for suspected VTE during pregnancy, there is limited data for postpartum individuals. OBJECTIVE: We conducted a scoping review to describe and evaluate diagnostic strategies used to investigate suspected VTE in postpartum individuals. METHODS: A comprehensive search strategy was conducted in Ovid MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (January 1, 2000-September 30, 2022) to identify original articles that reported on diagnostic strategies in postpartum individuals with suspected VTE...

BACKGROUND: Pulmonary embolism (PE) is a relatively rare vascular complication of acute pancreatitis (AP), and its mortality rate is high. To our knowledge, relevant literature reports still need to be summarized. In this study, we analyzed the clinical characteristics, treatment, and prognosis of five patients with AP complicated by PE and summarized and reviewed the relevant literature. METHODS: Clinical data of patients with AP complicated by PE treated in Taizhou Hospital of Zhejiang Province between January 2017 and September 2022 were retrospectively collected...

OBJECTIVES: The purpose of the clinical study was to evaluate the risk of chronic thromboembolic pulmonary hypertension (CTEPH) after splenectomy and to analyze some biochemical and coagulation parameters. BACKGROUND: CTEPH caused by incomplete resolution of thromboemboli and irreversible remodeling of the pulmonary arteries is a progressive, and without treatment a fatal disease. Although the definite etiopathophysiology is not quite perfectly researched, numerous clinical conditions associated with CTEPH as history of pulmonary embolism, infected ventriculoatrial shunts or permanent intravascular devices, high-dose thyroid hormone replacement, malignancy and chronic inflammatory diseases, including osteomyelitis, inflammatory bowel diseases, are well accepted...

Ventilation-perfusion matching occurs passively and is also actively regulated through hypoxic pulmonary vasoconstriction (HPV). The extent of HPV activity in humans, particularly normal subjects is uncertain. Current evaluation of HPV assesses changes in ventilation-perfusion relationships/pulmonary vascular resistance with hypoxia and are invasive, or unsuitable for patients because of safety concerns. We used a non-invasive imaging-based approach to quantify the pulmonary vascular response to oxygen as a metric of HPV by measuring perfusion changes between breathing 21% and 30%O2 using arterial spin labeling (ASL) MRI...

INTRODUCTION: The optimal diagnosis strategy for pulmonary embolism (PE) in the emergency department (ED) remains complex. This review summarizes PE diagnosis with clinical presentation, decision rules and investigations for acute PE. METHODS: This review was performed using studies published between January 1, 2010, and September 1, 2023. RESULTS: PE should be considered in ED in patients with chest pain, shortness of breath, syncope or signs of deep veinous thrombosis...

PURPOSE: Diagnosing pulmonary embolism (PE) in older adults is relatively difficult because of the atypical clinical symptoms of PE in older adults accompanied by multiple complications. This study aimed to establish a nomogram model to better predict the occurrence of PE in older adults. METHODS: Data were collected from older patients (≥65 years old) with suspected PE who were hospitalized between January 2012 and July 2021 and received confirmatory tests (computed tomographic pulmonary angiography or ventilation/perfusion scanning)...

Chest trauma is one of the most serious and difficult injuries, with various complications that can lead to ventilation-perfusion (V/Q) mismatch and systemic hypoxia. We are presenting a case of a 53-year-old male with no chronic therapy who was admitted to the Intensive Care Unit due to severe respiratory failure after chest trauma. He developed a right-sided pneumothorax, and then a thoracic drain was placed. On admission, the patient was hemodynamically unstable and tachypneic. He was intubated and mechanically ventilated, febrile (38...