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Intrathoracic pressure

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https://www.readbyqxmd.com/read/28338504/ventilation-with-high-or-low-tidal-volume-with-peep-does-not-influence-lung-function-after-spinal-surgery-in-prone-position-a-randomized-controlled-trial
#1
Sarah Soh, Jae-Kwang Shim, Yoon Ha, Young-Sam Kim, Hyelin Lee, Young-Lan Kwak
BACKGROUND: Spinal surgery in the prone position is accompanied by increased intrathoracic pressure and decreased respiratory compliance. This study investigated whether intraoperative lung protective mechanical ventilation improved lung function evaluated with pulmonary function tests in patients at risk of postoperative pulmonary complications (PPCs) after major spinal surgery in the prone position. METHODS: Seventy-eight patients at potential risk of PPCs were randomly assigned to the protective group (tidal volume; 6 mL/kg predicted body weight, 6 cm H2O positive end-expiratory pressure with recruitment maneuvers) or the conventional group (10 mL/kg predicted body weight, no positive end-expiratory pressure)...
March 23, 2017: Journal of Neurosurgical Anesthesiology
https://www.readbyqxmd.com/read/28329460/model-based-comparison-of-the-normal-and-fontan-circulatory-systems-part-iii
#2
Raymond L Watrous, Alvin J Chin
BACKGROUND: For patients with the Fontan circulatory arrangement, angiotensin-converting enzyme inhibition, guanylate cyclase activation, phosphodiesterase 5 inhibition, and endothelin receptor antagonism have so far resulted in little or no improvement in [Formula: see text] or peak cardiac index (CI), suggesting that our understanding of the factors that most impact the exercise hemodynamics is incomplete. METHODS: To facilitate comparisons with clinical reports of the exercise performance of preadolescent Fontan patients, we rescaled our previously reported computational models of a two-year-old normal child and similarly aged Fontan patient, extended our Fontan model to capture the nonlinear relationship between flow and resistance quantified from previous computational fluid dynamic analyses of the total cavopulmonary connection (TCPC), and added respiration as well as skeletal muscle contraction...
March 2017: World Journal for Pediatric & Congenital Heart Surgery
https://www.readbyqxmd.com/read/28294285/evaluation-of-a-flexible-bronchoscope-prototype-designed-for-bronchoscopy-during-mechanical-ventilation-a-proof-of-concept-study
#3
M-A Nay, A Auvet, J Mankikian, V Herve, P-F Dequin, A Guillon
Bronchoscopy during mechanical ventilation of patients' lungs significantly affects ventilation because of partial obstruction of the tracheal tube, and may thus be omitted in the most severely ill patients. It has not previously been possible to reduce the external diameter of the bronchoscope without reducing the diameter of the suction channel, thus reducing the suctioning capacity of the device. We believed that a better-designed bronchoscope could improve the safety of bronchoscopy in patients whose lungs were ventilated...
March 14, 2017: Anaesthesia
https://www.readbyqxmd.com/read/28288537/exit-procedure-for-fetal-mediastinal-teratoma-with-large-pericardial-effusion-a-case-report-with-review-of-literature
#4
Arpit Agarwal, Eliot Rosenkranz, Salih Yasin, Sethuraman Swaminathan
BACKGROUND: Large mediastinal teratomas in the fetus are rare and can present with direct compression of intrathoracic structures as well as pericardial and pleural effusions. Mediastinal fetal teratoma may be detected as a mass in the chest during a routine prenatal ultrasound. Because of the pressure on mediastinal structures it may result in non-immune fetal hydrops and polyhydramnios. The development of hydrops may lead to fetal demise. Timely obstetric and surgical removal is important to improve survival in this patient population...
March 13, 2017: Journal of Maternal-fetal & Neonatal Medicine
https://www.readbyqxmd.com/read/28261153/non-invasive-respiratory-impedance-enhances-cerebral-perfusion-in-healthy-adults
#5
Christopher G Favilla, Ashwin B Parthasarathy, John A Detre, Arjun G Yodh, Michael T Mullen, Scott E Kasner, Kimberly Gannon, Steven R Messé
Optimization of cerebral blood flow (CBF) is the cornerstone of clinical management in a number of neurologic diseases, most notably ischemic stroke. Intrathoracic pressure influences cardiac output and has the potential to impact CBF. Here, we aim to quantify cerebral hemodynamic changes in response to increased respiratory impedance (RI) using a non-invasive respiratory device. We measured cerebral perfusion under varying levels of RI (6 cm H2O, 9 cm H2O, and 12 cm H2O) in 20 healthy volunteers. Simultaneous measurements of microvascular CBF and middle cerebral artery mean flow velocity (MFV), respectively, were performed with optical diffuse correlation spectroscopy and transcranial Doppler ultrasound...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28250153/microinjection-of-kynurenic-acid-in-the-rostral-nucleus-of-the-tractus-solitarius-disrupts-spatiotemporal-aspects-of-mechanically-induced-tracheobronchial-cough
#6
Ivan Poliacek, Teresa Pitts, Melanie J Rose, Paul W Davenport, Michal Simera, Marcel Veternik, Zuzana Kotmanova, Donald C Bolser
The importance of neurons in the solitary tract nucleus (NTS) in the production of coughing was tested by microinjections of the non-specific glutamate receptor antagonist kynurenic acid (kyn; 100 mM in artificial cerebrospinal fluid) in 15 adult spontaneously breathing anesthetized cats. Repetitive coughing was elicited by mechanical stimulation of the intrathoracic airway. Electromyograms (EMG) were recorded from inspiratory parasternal and expiratory transversus abdominis muscles (ABD). Bilateral microinjections of kyn into the NTS rostral to obex (55±4 nl total in two locations; n=6 or 110±4 nl total in four locations; n=5), primarily the ventrolateral subnucleus, reduced cough number and expiratory cough efforts (amplitudes of ABD EMG and maxima of esophageal pressure) compared to control...
March 1, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28213202/determinants-of-cough-effectiveness-in-patients-with-respiratory-muscle-weakness
#7
Franco Laghi, Veeranna Maddipati, Timothy Schnell, W Edwin Langbein, Martin J Tobin
Experiments were undertaken to mechanistically define expiratory-muscle contribution to effectiveness of cough while controlling glottic movement. We hypothesized that electrical abdominal-muscle stimulation in patients with respiratory-muscle weakness produces effective coughs only when glottic closure accompanies coughs. In ten spinal-cord-injury patients, esophago-gastric pressure and airflow were recorded during solicited-coughs, coughs augmented by abdominal-muscle stimulation, and passive open-glottis exhalations...
February 16, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28198458/a-simple-method-for-noninvasive-quantification-of-pressure-gradient-across-the-pulmonary-valve
#8
Xueying Zhou, Changyang Xing, Yang Feng, Yunyou Duan, Qiangsun Zheng, Zuojun Wang, Jie Liu, Tiesheng Cao, Lijun Yuan
Pressure gradient across the pulmonary valve (PVPG) is an important hemodynamic variable used in the management of patients with cardiovascular and pulmonary disease. However, a reliable noninvasive method is unavailable. We hypothesized that a progressive Muller maneuver would elicit the pulmonary valve premature opening (PVPO) in diastole and that this event would be detectable by Doppler echocardiography. The intrathoracic pressure (ITP) decrease during this maneuver equals PVPG, which may be assessed with a custom airway pressure measurement device...
February 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28190583/fibrinogen-is-an-independent-predictor-of-mortality-in-major-trauma-patients-a-five-year-statewide-cohort-study
#9
Zoe K McQuilten, Erica M Wood, Michael Bailey, Peter A Cameron, David J Cooper
INTRODUCTION: Fibrinogen may be reduced following traumatic injury due to loss from haemorrhage, increased consumption and reduced synthesis. In the absence of clinical trials, guidelines for fibrinogen replacement are based on expert opinion and vary internationally. We aimed to determine prevalence and predictors of low fibrinogen on admission in major trauma patients and investigate association of fibrinogen levels with patient outcomes. PATIENTS AND METHODS: Data on all major trauma patients (January 2007-July 2011) identified through a prospective statewide trauma registry in Victoria, Australia were linked with laboratory and transfusion data...
November 21, 2016: Injury
https://www.readbyqxmd.com/read/28184275/postoperative-negative-pressure-pulmonary-edema-following-repetitive-laryngospasm-even-after-reversal-of-neuromuscular-blockade-by-sugammadex-a-case-report
#10
Ji Hyeon Lee, Jae Ho Lee, Min Hyun Lee, Hyun Oh Cho, Soon Eun Park
Laryngospasm, an occlusion of the glottis, can occur at any time during anesthesia, and is associated with serious perioperative complications such as hypoxia, hypercabia, aspiration, bronchospasm, arrhythmia, prolonged recovery, cardiac collapse, and eventually catastrophic death. Importantly, postoperative negative pressure pulmonary edema (NPPE) is a rare, but well described life-threatening complication related to acute and chronic upper airway obstruction. Sugammadex well known for affirmatively reducing the postoperative pulmonary complications associated with residual neuromuscular blockade may have an indirect role in triggering the negative intrathoracic pressure by raising a rapid and efficacious respiratory muscle strength in acute upper airway obstruction...
February 2017: Korean Journal of Anesthesiology
https://www.readbyqxmd.com/read/28178996/hemodynamic-effects-of-lung-recruitment-maneuvers-in-acute-respiratory-distress-syndrome
#11
Anup Das, Mainul Haque, Marc Chikhani, Oana Cole, Wenfei Wang, Jonathan G Hardman, Declan G Bates
BACKGROUND: Clinical trials have, so far, failed to establish clear beneficial outcomes of recruitment maneuvers (RMs) on patient mortality in acute respiratory distress syndrome (ARDS), and the effects of RMs on the cardiovascular system remain poorly understood. METHODS: A computational model with highly integrated pulmonary and cardiovascular systems was configured to replicate static and dynamic cardio-pulmonary data from clinical trials. Recruitment maneuvers (RMs) were executed in 23 individual in-silico patients with varying levels of ARDS severity and initial cardiac output...
February 8, 2017: BMC Pulmonary Medicine
https://www.readbyqxmd.com/read/28161892/osa-and-cardiometabolic-risk-what-s-the-bottom-line
#12
REVIEW
Camilla M Hoyos, Luciano F Drager, Sanjay R Patel
Obstructive sleep apnoea (OSA) is a common condition characterized by repetitive upper airway obstruction during sleep. OSA promotes wide intrathoracic pressure swings, intermittent hypoxia and sleep fragmentation. Growing evidence derived from animal models mimicking the oxygen profile observed in patients with OSA as well as clinical studies support that this important sleep-disordered breathing is associated with increased cardiovascular risk. Although the precise mechanisms are not fully established, it is conceivable that the metabolic deregulation promoted by the components of OSA may have an important causal role in the poor cardiovascular prognosis...
April 2017: Respirology: Official Journal of the Asian Pacific Society of Respirology
https://www.readbyqxmd.com/read/28144067/stenting-of-critical-tracheal-stenosis-with-adjuvant-cardio-pulmonary-bypass
#13
Himanshu Bhardwaj, Ahmed Awab, Houssein A Youness, Brent Brown
Severe and critical central airway obstruction causing impaired ventilation and/or oxygenation can impose tremendous challenges on the interventional pulmonologist. Near total airway obstruction can rapidly evolve into potentially fatal complete airway occlusion during bronchoscopic airway manipulation under moderate sedation; as well as during the induction of the general anesthesia. Although there are currently interventional pulmonary procedures available to tackle the critical airway obstruction in extreme situations, cardio-pulmonary bypass should be considered prior to the intervention to maintain the adequate gas exchange during the procedure...
January 2017: Lung India: Official Organ of Indian Chest Society
https://www.readbyqxmd.com/read/28137972/identification-of-the-upward-movement-of-human-cerebrospinal-fluid-in-vivo-and-its-relation-to-the-brain-venous-system
#14
Steffi Dreha-Kulaczewski, Arun A Joseph, Klaus-Dietmar Merboldt, Hans-Christoph Ludwig, Jutta Gärtner, Jens Frahm
Cerebrospinal fluid (CSF) flux is involved in the pathophysiology of neurodegenerative diseases and cognitive impairment after traumatic brain injury, all hallmarked by the accumulation of cellular metabolic waste. Its effective disposal via various CSF routes has been demonstrated in animal models. In contrast, the CSF dynamics in humans are still poorly understood. Forced Inspiration has recently been identified as a main driving force of CSF flow in the human brain using novel real-time magnetic resonance imaging (MRI)...
January 30, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28126503/-pathophysiology-of-obstructive-sleep-apnea-syndrome-and-its-cardiometabolic-consequences
#15
Marie Destors, Renaud Tamisier, Louis-Marie Galerneau, Patrick Lévy, Jean-Louis Pepin
Obstructive sleep apnoea syndrome (OSAS) is characterized by recurrent partial or complete pharyngeal collapses during sleep. The pathophysiology of OSAS is complex and multifactorial. Factors influencing upper airway patency include a reduction in upper airway dimensions that can result from both anatomical and functional alterations (obesity, fluid shift or maxillo-facial structural changes), and increased pharyngeal collapsibility owing to reduced neuromuscular compensation and lack of the pharyngeal protective reflex during sleep...
January 23, 2017: La Presse Médicale
https://www.readbyqxmd.com/read/28040290/obstructive-sleep-and-atrial-fibrillation-pathophysiological-mechanisms-and-therapeutic-implications
#16
REVIEW
Christos A Goudis, Dimitrios G Ketikoglou
Atrial fibrillation (AF) is the commonest arrhythmia in clinical practice and is associated with increased cardiovascular morbidity and mortality. Obstructive sleep apnea (OSA), a common breathing disorder, is an independent risk factor for AF. Several pathophysiological mechanisms, including apnea-induced hypoxia, intrathoracic pressure shifts, sympathovagal imbalance, atrial remodeling, oxidative stress, inflammation and neurohumoral activation have been implicated in the occurrence of AF in OSA patients...
March 1, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28039409/internal-jugular-pressure-increases-during-parabolic-flight
#17
David S Martin, Stuart M C Lee, Timothy P Matz, Christian M Westby, Jessica M Scott, Michael B Stenger, Steven H Platts
One hypothesized contributor to vision changes experienced by >75% of International Space Station astronauts is elevated intracranial pressure (ICP). While no definitive data yet exist, elevated ICP might be secondary to the microgravity-induced cephalad fluid shift, resulting in venous congestion (overfilling and distension) and inhibition of cerebrospinal and lymphatic fluid drainage from the skull. The objective of this study was to measure internal jugular venous pressure (IJVP) during normo- and hypo-gravity as an index of venous congestion...
December 2016: Physiological Reports
https://www.readbyqxmd.com/read/28018763/predicting-central-venous-pressure-by-measuring-femoral-venous-diameter-using-ultrasonography
#18
Akram Malik, Aftab Akhtar, Shoab Saadat, Salman Mansoor
OBJECTIVES: The objective of this exploratory study was to find out the correlation of femoral vein diameter (FVD) to central venous pressure (CVP) measurements and to derive a prediction equation to help ascertain the fluid volume status in a critical patient. PATIENTS AND METHODS: This was a single-centered prospective cohort study designed and conducted by the critical care department of Shifa International hospital in Islamabad, Pakistan. Patients were enrolled from the medical and surgical intensive care units...
November 23, 2016: Curēus
https://www.readbyqxmd.com/read/28007877/mechanical-reperfusion-with-leucocyte-filtered-blood-does-not-prevent-injury-following-global-cerebral-ischaemia
#19
Rickard P F Lindblom, Thomas Tovedal, Bo Norlin, Lars Hillered, Svetlana N Popova, Irina Alafuzoff, Stefan Thelin
OBJECTIVES: Prolonged global cerebral ischaemia leads to irreversible injury, often with lethal outcome. Brain injuries are partly caused by the uncontrolled reperfusion that occurs once the circulation is re-established. Recent animal experiments suggest that controlled reperfusion following lengthy ischaemia might prevent severe brain injury. This study aimed at further exploring cerebral alterations and outcome following prolonged global cerebral ischaemia and mechanically manipulated reperfusion...
December 22, 2016: European Journal of Cardio-thoracic Surgery
https://www.readbyqxmd.com/read/28000205/early-severe-acute-respiratory-distress-syndrome-what-s-going-on-part-ii-controlled-vs-spontaneous-ventilation
#20
REVIEW
Fabrice Petitjeans, Cyrille Pichot, Marco Ghignone, Luc Quintin
The second part of this overview on early severe ARDS delineates the pros and cons of the following: a) controlled mechanical ventilation (CMV: lowered oxygen consumption and perfect patient-to-ventilator synchrony), to be used during acute cardio-ventilatory distress in order to "buy time" and correct circulatory insufficiency and metabolic defects (acidosis, etc.); b) spontaneous ventilation (SV: improved venous return, lowered intrathoracic pressure, absence of muscle atrophy). Given a stabilized early severe ARDS, as soon as the overall clinical situation improves, spontaneous ventilation will be used with the following stringent conditionalities: upfront circulatory optimization, upright positioning, lowered VO2, lowered acidotic and hypercapnic drives, sedation without ventilatory depression and without lowered muscular tone, as well as high PEEP (titrated on transpulmonary pressure, or as a second best: "trial"-PEEP) with spontaneous ventilation + pressure support (or newer modes of ventilation)...
2016: Anaesthesiology Intensive Therapy
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