Perfusion pressure

The study aimed to investigate the effect of red blood cell (RBC) morphology on oxygenator perfusion, focusing on stages of echinocytosis and their correlation with blood viscosity. A test circuit with an oxygenator and human RBC mixtures was used to induce changes in RBC shape by increasing sodium salicylate concentrations (0, 10, 20, 30, 60, and 120 mmol/L), while hematocrit, blood temperature, and anticoagulation were maintained. Blood viscosity was measured using a continuous blood viscosity monitoring system based on pressure-flow characteristics...

OBJECTIVE: Subarachnoid hemorrhage (SAH) is characterized by intense central inflammation, leading to substantial post-hemorrhagic complications such as vasospasm and delayed cerebral ischemia. 2,6,7 Given the anti-inflammatory effect of transcutaneous auricular vagus nerve stimulation (taVNS) and its ability to promote brain plasticity, taVNS has emerged as a promising therapeutic option for SAH patients. 3,8,9 However, the effects of taVNS on cardiovascular dynamics in critically ill patients like those with SAH have not yet been investigated...

We report a rare case of jaw claudication following fenestrated thoracic endovascular aortic repair for a saccular aortic arch aneurysm. The brachiocephalic artery (BCA) was preserved with fenestration and intentionally half covered. Although discharged without any complications 2 weeks after the procedure, the patient subsequently experienced right mandibular fatigue at mealtime and hypotension in the right upper extremity. Angiography revealed a flap-like structure in the BCA orifice, with a 100-mm Hg pressure gradient between the aorta and BCA...

Pulse oximetry represents a ubiquitous clinical application of optics in modern medicine. Recent studies have raised concerns regarding the potential impact of confounders, such as variable skin pigmentation and perfusion, on blood oxygen saturation measurement accuracy in pulse oximeters. Tissue-mimicking phantom testing offers a low-cost, well-controlled solution for characterizing device performance and studying potential error sources, which may thus reduce the need for costly in vivo trials. The purpose of this study was to develop realistic phantom-based test methods for pulse oximetry...

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Cell replacement in aganglionic intestines is a promising, yet merely experimental tool for the therapy of congenital dysganglionosis of the enteric nervous system like Hirschsprung disease. While the injection of single cells or neurospheres to a defined and very restricted location is trivial, the translation to the clinical application, where large aganglionic or hypoganglionic areas need to be colonized (hundreds of square centimetres), afford a homogeneous distribution of multiple neurospheres all over the affected tissue areas...

BACKGROUND: During one-lung ventilation (OLV), positive end-expiratory pressure (PEEP) can improve lung aeration, but might over-distend lung units and increase intrapulmonary shunt. We hypothesized that higher PEEP shifts pulmonary perfusion from the ventilated to the non-ventilated lung, resulting in a U-shaped relationship with intrapulmonary shunt during OLV. METHODS: In nine anesthetized female pigs, a thoracotomy was performed and intravenous lipopolysaccharide infused to mimic the inflammatory response of thoracic surgery...

The efficacy of extracranial-intracranial (EC-IC) bypass in preventing ischemic stroke progression and recurrence is controversial. As per the current hypothesis, EC-IC bypass is most beneficial for patients with persistent hemodynamic insufficiency. Hence, various approaches have been used to evaluate hemodynamic insufficiency, including repeated single photon emission CT (SPECT) imaging or continuous monitoring of cerebral flow with transcranial Doppler ultrasound (TCD). However, both modalities are time- and resource-intensive...

The emergence of parkinsonism in a patient with an intracranial meningioma is indeed an uncommon occurrence. Here, we detail the case of a patient experiencing parkinsonian syndrome for four years without any observable clinical improvement following medical treatment. A magnetic resonance imaging (MRI) of the brain revealed a left intracranial meningioma. The successful complete surgical removal of the tumor led to the resolution of parkinsonian syndrome. The extent of the neoplasm and the surrounding peritumoral edema could potentially exert significant pressure, thereby compromising perfusion in the basal ganglia region...

OBJECTIVES: We analyzed resuscitation practices in Cameroonian patients with trauma as a first step toward developing a context-appropriate resuscitation protocol. We hypothesized that more patients would receive crystalloid-based (CB) resuscitation with a faster time to administration than blood product (BL) resuscitation. METHODS: We included patients enrolled between 2017 and 2019 in the Cameroon Trauma Registry (CTR). Patients presenting with hemorrhagic shock (systolic blood pressure (SBP) <100 mm Hg and active bleeding) were categorized as receiving CB, BL, or no resuscitation (NR)...

BACKGROUND: We developed and tested the safety and efficacy of a cosmetic device to improve dark circles using electrical muscle stimulation of the orbicularis oculi muscle. METHODS: Overall, 18 participants (36 eyes) were studied. The following five items were evaluated before and after the intervention:(1) the Clinical Dark Circle Score using clinical findings and photographs, (2) transcutaneous oxygen partial pressure (TcPO2 ) on the lower eyelid, (3) thermography, (4) two-dimensional laser blood flowmetry, and (5) spectrophotometry...

Mean airway pressure (MAP) is the mean pressure generated in the airway during a single breath (inspiration + expiration), and is displayed on most anaesthesia and intensive care ventilators. This parameter, however, is not usually monitored during mechanical ventilation because it is poorly understood and usually only used in research. One of the main determinants of MAP is PEEP. This is because in respiratory cycles with an I:E ratio of 1:2, expiration is twice as long as inspiration. Although MAP can be used as a surrogate for mean alveolar pressure, these parameters differ considerably in some situations...

BACKGROUND: In contrast to other musculoskeletal tissues, the normal pressure behavior of the Achilles tendon is poorly understood. This study aimed to explore the normal intratendinous and perfusion pressures of the Achilles tendon at rest and during exercise, and investigate potential correlations with tendon load and morphology. HYPOTHESIS: Intratendinous and perfusion pressures of the Achilles tendon exhibit similarities to other musculoskeletal tissues and depend on tendon load and morphology...

Smoking may increase the risk of diabetic foot disease and ulceration. It does so by impairing glycaemic control and promoting the formation of advanced glycated end-products. Additionally, smoking is known to delay surgical wound healing and accelerate peripheral arterial disease. We aimed to determine whether toe pressures differed in smokers with a foot ulcer, when compared to non-smokers and ex-smokers, as well as ulcer outcomes at 12 months, among patients attending Blacktown Hospital High Risk Foot Service (HRFS)...

The coronary circulation has the inherent ability to maintain myocardial perfusion constant over a wide range of perfusion pressures. The phenomenon of pressure-flow autoregulation is crucial in response to flow-limiting atherosclerotic lesions which diminish coronary driving pressure and increase risk of myocardial ischemia and infarction. Despite well over half a century of devoted research, understanding of the mechanisms responsible for autoregulation remains one of the most fundamental and contested questions in the field today...

Radiation delivered over ultra-short timescales ("FLASH" radiotherapy) leads to a reduction in normal tissue toxicities for a range of tissues in the preclinical setting. Experiments have shown this reduction occurs for total delivery times less than a "critical" time that varies by two orders of magnitude between brain (∽0.3 s) and skin (≳ 10 s), and three orders of magnitude across different bowel experiments, from ∽0.01 s to ≳ (1-10) s. Understanding the factors responsible for this broad variation may be important for translation of FLASH into the clinic and understanding the mechanisms behind FLASH...

BACKGROUND: Myocardial flow reserve (MFR) by positron emission tomography (PET) is a validated measure of cardiovascular risk. Elevated resting rate pressure product (RPP = heart rate x systolic blood pressure) can cause high resting myocardial blood flow (MBF), resulting in reduced MFR despite normal/near-normal peak stress MBF. When resting MBF is high, it is not known if RPP-corrected MFR (MFRcorrected) helps reclassify CV risk. We aimed to study this question in patients without obstructive coronary artery disease (CAD)...

BACKGROUND: Acute kidney injury is a common postoperative complication of paediatric cardiac surgery associated with increased morbidity and mortality. The purpose of this study is to characterise associations between haemodynamic parameters, clinical parameters, and medical interventions, on acute kidney injury. METHODS: Nine patients with univentricular physiology undergoing the Norwood procedure from a single-centre tertiary care paediatric cardiac ICU were included (September 2022 to March 2023)...

INTRODUCTION: PRx can be used as surrogate measure of Cerebral Autoregulation (CA) in traumatic brain injury (TBI) patients. PRx can provide means for individualising cerebral perfusion pressure (CPP) targets, such as CPPopt. However, a recent Delphi consensus of clinicians concluded that consensus could not be reached on the accuracy, reliability, and validation of any current CA assessment method. RESEARCH QUESTION: We aimed to quantify the short-term uncertainty of PRx time-trends and to relate this to other physiological measurements...

PURPOSE: This study aims to describe the total EEG energy during episodes of intracranial hypertension (IH) and evaluate its potential as a classification feature for IH. NEW METHODS: We computed the sample correlation coefficient between intracranial pressure (ICP) and the total EEG energy. Additionally, a generalized additive model was employed to assess the relationship between arterial blood pressure (ABP), total EEG energy, and the odds of IH. RESULTS: The median sample cross-correlation between total EEG energy and ICP was 0...