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Christian Lind Malte, Jonas Bundgaard, Michael Schou Jensen, Mads Frost Bertelsen, Tobias Wang
Morphine and other opioids cause respiratory depression in high doses and lower the ventilatory responses to hypoxia and hypercapnia in mammals. Recent studies indicate that turtles respond similarly, but although they are used routinely for post-surgical analgesia, little is known about the physiological effects of opioids in reptiles. We therefore investigated the effects of morphine (10 and 20 mg kg-1 ) on gas exchange and ventilation in six dwarf caiman (Paleosuchus palpebrosus) using pneumotachography in a crossover design...
March 16, 2018: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Ravindranath Tiruvoipati, David Pilcher, John Botha, Hergen Buscher, Robert Simister, Michael Bailey
Importance: Clinical studies investigating the effects of hypercapnia and hypercapnic acidosis in acute cerebral injury are limited. The studies performed so far have mainly focused on the outcomes in relation to the changes in partial pressure of carbon dioxide and pH in isolation and have not evaluated the effects of partial pressure of carbon dioxide and pH in conjunction. Objective: To review the association of compensated hypercapnia and hypercapnic acidosis during the first 24 hours of intensive care unit admission on hospital mortality in adult mechanically ventilated patients with cerebral injury...
March 19, 2018: JAMA Neurology
Helmut Trimmel, Christoph Beywinkler, Sonja Hornung, Janett Kreutziger, Wolfgang G Voelckel
BACKGROUND: Competence in emergency airway management is key in order to improve patient safety and outcome. The scope of compulsory training for emergency physicians or paramedics is quite limited, especially in Austria. The purpose of this study was to review the difficult airway management performance of an emergency medical service (EMS) in a region that has implemented a more thorough training program than current regulations require, comprising 3 months of initial training and supervised emergency practice and 3 days/month of on-going in-hospital training as previously reported...
March 16, 2018: International Journal of Emergency Medicine
Zhenyuan Cai, Liuyang Wang, Xiaoying Song, Somnath Tagore, Xiangfeng Li, Huihua Wang, Jiarui Chen, Kexin Li, Zeev Frenkel, Dahai Gao, Milana Frenkel-Morgenstern, Tongzuo Zhang, Eviatar Nevo
Animals living at high altitudes have evolved distinct phenotypic and genotypic adaptations against stressful environments. We studied the adaptive patterns of altitudinal stresses on transcriptome turnover in subterranean plateau zokors (Myospalax baileyi) in the high-altitude Qinghai-Tibetan Plateau. Transcriptomes of zokors from three populations with distinct altitudes and ecologies (Low: 2846 m, Middle: 3282 m, High: 3,714 m) were sequenced and compared. Phylogenetic and principal component analyses classified them into three divergent altitudinal population clusters...
March 16, 2018: Scientific Reports
Ryan L Sheppard, Joshua M Swift, Aaron Hall, Richard T Mahon
Introduction: Individuals with a known susceptibility to high altitude pulmonary edema (HAPE) demonstrate a reduced ventilation response and increased pulmonary vasoconstriction when exposed to hypoxia. It is unknown whether reduced sensitivity to hypercapnia is correlated with increased incidence and/or severity of HAPE, and while acute exercise at altitude is known to exacerbate symptoms the effect of exercise training on HAPE susceptibility is unclear. Purpose: To determine if chronic intermittent hypercapnia and exercise increases the incidence of HAPE in rats...
2018: Frontiers in Physiology
Christian Viniol, Claus F Vogelmeier
Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. While COPD is a mainly chronic disease, a substantial number of patients suffer from exacerbations. Severe exacerbations are related to a significantly worse survival outcome. This review summarises the current knowledge on the different aspects of COPD exacerbations. The impact of risk factors and triggers such as smoking, severe airflow limitation, bronchiectasis, bacterial and viral infections and comorbidities is discussed...
March 31, 2018: European Respiratory Review: An Official Journal of the European Respiratory Society
Jungyun Hwang, Kiyoung Kim, R Matthew Brothers, Darla M Castelli, F Gonzalez-Lima
Studies of the effects of physical activity on cognition suggest that aerobic fitness can improve cognitive abilities. However, the physiological mechanisms for the cognitive benefit of aerobic fitness are less well understood. We examined the association between aerobic fitness and cerebrovascular function with neurocognitive functions in healthy, young adults. Participants aged 18-29 years underwent measurements of cerebral vasomotor reactivity (CVMR) in response to rebreathing-induced hypercapnia, maximal oxygen uptake (VO2 max) during cycle ergometry to voluntary exhaustion, and simple- and complex-neurocognitive assessments at rest...
March 14, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
S Höstman, R Kawati, G Perchiazzi, A Larsson
BACKGROUND: In a previous study, we found a rebound of arterial carbon dioxide tension (PaCO2 ) after stopping THAM buffer administration. We hypothesized that this was due to reduced pulmonary CO2 elimination during THAM administration. The aim of this study was to investigate this hypothesis in an experimental porcine hypercapnic model. METHODS: In seven, initially normoventilated, anesthetized pigs (22-27 kg) minute ventilation was reduced by 66% for 7 h. Two hours after commencing hypoventilation, THAM was infused IV for 3 h in a dose targeting a pH of 7...
March 12, 2018: Acta Anaesthesiologica Scandinavica
James R Sackett, Zachary J Schlader, Morgan C O'Leary, Christopher L Chapman, Blair D Johnson
NEW FINDINGS: What is the central question of the study? Is central chemosensitivity blunted during thermoneutral head out water immersion in healthy humans? What is the main finding and its importance? Central chemosensitivity is augmented during thermoneutral head out water immersion in healthy men and women. Thus, we suggest that the central chemoreceptors do not contribute CO2 retention during head out water immersion. ABSTRACT: Carbon dioxide (CO2 ) retention occurs during water immersion...
March 12, 2018: Experimental Physiology
Yuko Nakamura, Yoshiaki Saito, Norika Kubota, Wataru Matsumura, Chika Hosoda, Akiko Tamasaki-Kondo, Yoko Nishimura, Yoshihide Sunada, Masuyuki Fukada, Takako Ohno, Yoshihiro Maegaki, Masafumi Matsuo, Yasuko Tokita
AIM: To report on sleep hypercapnia in Becker muscular dystrophy (BMD) at earlier stages than ever recognized. SUBJECTS AND METHODS: This retrospective study examined nocturnal hypercapnia in six young Becker muscular dystrophy (BMD) patients with deletions of one or more exons of DMD gene. Clinical information, consecutive data on forced vital capacity (FVC%), forced expiratory volume in one second (FEV1%), peak expiratory flow (PEF%), peak cough flow (PCF), average PCO2 in all-night monitoring, and left ventricular ejection fraction (LVEF) were reviewed...
March 8, 2018: Brain & Development
Paul Gavra, André Y Denault, Yves Théoret, Louis P Perrault, France Varin
OBJECTIVES: Milrinone pulmonary administration is used currently for the treatment of pulmonary hypertension. Several methods are available: simple jet nebulization, vibrating mesh nebulization, intratracheal instillation, and intratracheal atomization. The aim of this study was to explore the concentration-effect relationship of milrinone for each of these methods. DESIGN: Observational open-label pharmacokinetic/pharmacodynamics cohort study. SETTING: Single-center, hospital animal laboratory...
January 31, 2018: Journal of Cardiothoracic and Vascular Anesthesia
Tracy Ssali, Udunna C Anazodo, Jonathan D Thiessen, Frank S Prato, Keith St Lawrence
While positron emission tomography (PET) with15 O-water is the gold standard for imaging cerebral blood flow (CBF), quantification requires measuring the arterial input function (AIF), which is an invasive and noisy procedure. To circumvent this problem, we propose a non-invasive PET/ magnetic resonance (MR) approach that eliminates the need to measure the AIF by using global CBF determined by phase-contrast (PC) magnetic resonance imaging (MRI) as a reference region. Not only is this approach non-invasive, it adds no additional imaging time as PC MRI and15 O-water PET are acquired simultaneously...
March 9, 2018: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
Colin A Nurse, Erin M Leonard, Shaima Salman
Mammalian carotid bodies (CB) are chemosensory organs that mediate compensatory cardiorespiratory reflexes in response to low blood PO2 (hypoxemia) and elevated CO2 /H+ (acid hypercapnia). The chemoreceptors are glomus or type I cells which occur in clusters enveloped by neighboring glial-like type II cells. During chemoexcitation type I cells depolarize, leading to Ca2+ -dependent release of several neurotransmitters, some excitatory and others inhibitory, which help shape the afferent carotid sinus nerve (CSN) discharge...
March 9, 2018: Physiological Genomics
Athir Morad, Salia Farrokh, Alexander Papangelou
PURPOSE OF REVIEW: Pain management in neurocritical care is a subject often avoided because of concerns over the side-effects of analgesics and the potential to cause additional neurological injury with treatment. The sedation and hypercapnia caused by opioids have been feared to mask the neurological examination and contribute to elevations in intracranial pressure. Nevertheless, increasing attention to patient satisfaction has sparked a resurgence in pain management. As opioids have remained at the core of analgesic therapy, the increasing attention to pain has contributed to a growing epidemic of opioid dependence...
April 2018: Current Opinion in Critical Care
Jeanette P Brown, Kristy A Bauman, Armando Kurili, Gianna M Rodriguez, Anthony E Chiodo, Robert G Sitrin, Helena M Schotland
STUDY DESIGN: Prospective, cohort study. OBJECTIVES: To evaluate the effectiveness of bi-level positive airway pressure (PAP) therapy and the patterns of use for sleep-disordered breathing (SDB) in individuals with spinal cord injury (SCI). SETTING: Academic tertiary care center, USA. METHODS: Overall, 91 adults with C1-T6 SCI for ≥3 months were recruited and 74 remained in the study to be evaluated for SDB and follow-up...
March 7, 2018: Spinal Cord
Baraa K Al-Khazraji, Leena N Shoemaker, Joseph S Gati, Trevor Szekeres, J Kevin Shoemaker
The larger intracranial conduit vessels contribute to the total cerebral vascular resistance, and understanding their vasoreactivity to physiological stimuli is required when attempting to understand regional brain perfusion. Reactivity of the larger cerebral conduit arteries remains understudied due to a need for improved imaging methods to simultaneously assess these vessels in a single stimulus. We characterized reactivity of basal intracranial conduit arteries (basilar, right and left posterior, middle and anterior cerebral arteries) and the right and left internal carotid arteries, to manipulations in end-tidal CO2 (PetCO2 )...
January 1, 2018: Journal of Cerebral Blood Flow and Metabolism
Anthony R Bain, Ivan Drvis, Zeljko Dujic, David B MacLeod, Philip N Ainslie
NEW FINDINGS: What is the topic of this review? This review provides an up-to-date assessment of the physiology involved with extreme static dry-land breath holding in trained apneists. What advances does it highlight? We specifically highlight the recent findings involved with the cardiovascular, cerebrovascular, and metabolic function during a maximal breath hold in elite apneists. ABSTRACT: Breath hold related activities have been performed for centuries, but only recently within the last ∼30 years has it emerged as an increasingly popular competitive sport...
March 7, 2018: Experimental Physiology
Elie Azoulay, Virginie Lemiale, Djamel Mokart, Saad Nseir, Laurent Argaud, Frédéric Pène, Loay Kontar, Fabrice Bruneel, Kada Klouche, François Barbier, Jean Reignier, Anabelle Stoclin, Guillaume Louis, Jean-Michel Constantin, Julien Mayaux, Florent Wallet, Achille Kouatchet, Vincent Peigne, Pierre Perez, Christophe Girault, Samir Jaber, Johanna Oziel, Martine Nyunga, Nicolas Terzi, Lila Bouadma, Christine Lebert, Alexandre Lautrette, Naike Bigé, Jean-Herlé Raphalen, Laurent Papazian, Antoine Rabbat, Michael Darmon, Sylvie Chevret, Alexandre Demoule
BACKGROUND: Acute respiratory failure (ARF) is the leading reason for intensive care unit (ICU) admission in immunocompromised patients. High-flow nasal oxygen (HFNO) therapy is an alternative to standard oxygen. By providing warmed and humidified gas, HFNO allows the delivery of higher flow rates via nasal cannula devices, with FiO2 values of nearly 100%. Benefits include alleviation of dyspnea and discomfort, decreased respiratory distress and decreased mortality in unselected patients with acute hypoxemic respiratory failure...
March 5, 2018: Trials
Dang Diem Tuong, Brittney Borowiec, Alexander M Clifford, Renato Filogonio, Derek Somo, Do Thi Thanh Huong, Nguyen Thanh Phuong, Tobias Wang, Mark Bayley, William K Milsom
The aim of the present study was to determine the roles of externally versus internally oriented CO2 /H+ -sensitive chemoreceptors in promoting cardiorespiratory responses to environmental hypercarbia in the facultative air-breathing fish, Chitala ornata (the clown knifefish). Fish were exposed to environmental acidosis (pH ~ 6.0) or hypercarbia (≈ 30 torr PCO2 ) that produced changes in water pH equal to the pH levels of the acidotic water to distinguish the relative roles of CO2 versus H+ . We also injected acetazolamide to elevate arterial levels of PCO2 and [H+ ] in fish in normocarbic water to distinguish between internal and external stimuli...
March 3, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Hugo Angleys, Sune N Jespersen, Leif Østergaard
Neurovascular coupling mechanisms give rise to vasodilation and functional hyperemia upon neural activation, thereby altering blood oxygenation. This blood oxygenation level dependent (BOLD) contrast allows studies of activation patterns in the working human brain by functional MRI (fMRI). The BOLD-weighted fMRI signal shows characteristic transients in relation to functional activation, such as the so-called initial dip, overshoot, and post-stimulus undershoot. These transients are modulated by other physiological stimuli and in disease, but the underlying physiological mechanisms remain incompletely understood...
March 2, 2018: Human Brain Mapping
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