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Hypercapnia

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https://www.readbyqxmd.com/read/28099291/transcutaneous-carbon-dioxide-measurements-in-women-receiving-intrathecal-morphine-for-cesarean-delivery-a-prospective-observational-study
#1
Jeanette R Bauchat, Robert McCarthy, Paul Fitzgerald, Stephen Kolb, Cynthia A Wong
BACKGROUND: Neuraxial morphine is the most commonly used analgesic technique after cesarean delivery. The incidence of respiratory depression is reported to be very low (0%-1.2%) in this patient population as measured by pulse oximetry and respiratory rates. However, hypercapnia may be a more sensitive measure of respiratory depression. In the current study, the incidence of hypercapnia events (transcutaneous CO2 [TcCO2] >50 mm Hg) for ≥2-minute duration was evaluated using the Topological Oscillation Search with Kinematical Analysis monitor in women who received intrathecal morphine for postcesarean delivery analgesia...
January 17, 2017: Anesthesia and Analgesia
https://www.readbyqxmd.com/read/28092273/in-vivo-testing-of-extracorporeal-membrane-ventilators-ila-activve%C3%A2-vs-prototype-i-lung%C3%A2
#2
Sabine Kischkel, Stefan Bergt, Beate Brock, Johan von Grönheim, Anne Herbst, Marc-Jonas Epping, Georg Matheis, Esther Novosel, Joerg Schneider, Philipp Warnke, Andreas Podbielski, Jan P Roesner, Peter I Lelkes, Brigitte Vollmar
A side-by-side comparison of the decarboxylation efficacy of two pump-driven veno-venous extracorporeal lung assist devices, i.e. a first prototype of the new miniaturized ambulatory extracorporeal membrane ventilator, I-lung® versus the commercial system iLA-activve® over a period of 72 hours in a large animal model.Fifteen German Landrace pigs were anesthetized and underwent mechanical hypoventilation to induce severe hypercapnia. Decarboxylation was accomplished by either the I-lung® or the iLA-activve® via a double lumen catheter in the jugular vein...
January 4, 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/28071964/hypercapnia-is-essential-to-reduce-the-cerebral-oxidative-metabolism-during-extreme-apnea-in-humans
#3
Anthony R Bain, Philip N Ainslie, Otto F Barak, Ryan L Hoiland, Ivan Drvis, Tanja Mijacika, Damian M Bailey, Antoinette Santoro, Daniel K DeMasi, Zeljko Dujic, David B MacLeod
The cerebral metabolic rate of oxygen (CMRO2) is reduced during apnea that yields profound hypoxia and hypercapnia. In this study, to dissociate the impact of hypoxia and hypercapnia on the reduction in CMRO2, 11 breath-hold competitors completed three apneas under: (a) normal conditions (NM), yielding severe hypercapnia and hypoxemia, (b) with prior hyperventilation (HV), yielding severe hypoxemia only, and (c) with prior 100% oxygen breathing (HX), yielding the greatest level of hypercapnia, but in the absence of hypoxemia...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28060323/a-model-to-simulate-clinically-relevant-hypoxia-in-humans
#4
Lars Eichhorn, Florian Kessler, Volker Böhnert, Felix Erdfelder, Anja Reckendorf, Rainer Meyer, Richard K Ellerkmann
In case of apnea, arterial partial pressure of oxygen (pO2) decreases, while partial pressure of carbon dioxide (pCO2) increases. To avoid damage to hypoxia sensitive organs such as the brain, compensatory circulatory mechanisms help to maintain an adequate oxygen supply. This is mainly achieved by increased cerebral blood flow. Intermittent hypoxia is a commonly seen phenomenon in patients with obstructive sleep apnea. Acute airway obstruction can also result in hypoxia and hypercapnia. Until now, no adequate model has been established to simulate these dynamics in humans...
December 22, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28058956/neuromuscular-blockade-and-inspiratory-breath-hold-during-stereotactic-body-radiation-therapy-for-treatment-of-heart-base-tumors-in-four-dogs
#5
Krista L Kelsey, Lyndsay N Kubicek, Nicholas J Bacon, Terry Torres, Sheilah A Robertson
CASE DESCRIPTION 4 dogs were examined because of pleural effusion and ventricular tachycardia, coughing and supraventricular tachycardia, appendicular osteosarcoma, and syncopal episodes. CLINICAL FINDINGS In all 4 dogs, a heart base tumor was identified by means of thoracic CT. TREATMENT AND OUTCOME In all 4 dogs, the heart base tumors were treated by means of stereotactic body radiation therapy. Dogs were anesthetized, and neuromuscular blockade was achieved with atracurium or vecuronium. A circle rebreathing system with 15 m (50 feet) of anesthetic tubing coursing through the vault wall was used to connect the patient to the anesthesia machine, which was located in the control room...
January 15, 2017: Journal of the American Veterinary Medical Association
https://www.readbyqxmd.com/read/28054939/effects-of-resveratrol-on-cognitive-performance-mood-and-cerebrovascular-function-in-post-menopausal-women-a-14-week-randomised-placebo-controlled-intervention-trial
#6
Hamish M Evans, Peter R C Howe, Rachel H X Wong
We tested whether chronic supplementation with resveratrol (a phytoestrogen) could improve cerebrovascular function, cognition and mood in post-menopausal women. Eighty post-menopausal women aged 45-85 years were randomised to take trans-resveratrol or placebo for 14 weeks and the effects on cognitive performance, cerebral blood flow velocity and pulsatility index (a measure of arterial stiffness) in the middle cerebral artery (using transcranial Doppler ultrasound), and cerebrovascular responsiveness (CVR) to both cognitive testing and hypercapnia were assessed...
January 3, 2017: Nutrients
https://www.readbyqxmd.com/read/28053973/noninvasive-ventilation-during-the-weaning-process-in-chronically-critically-ill-patients
#7
Jesus Sancho, Emilio Servera, Luis Jara-Palomares, Emilia Barrot, Raquel Sanchez-Oro-Gómez, F Javier Gómez de Terreros, M Jesús Martín-Vicente, Isabel Utrabo, M Belen Núñez, Alicia Binimelis, Ernest Sala, Enrique Zamora, Gonzalo Segrelles, Angel Ortega-Gonzalez, Fernando Masa
Chronically critically ill patients often undergo prolonged mechanical ventilation. The role of noninvasive ventilation (NIV) during weaning of these patients remains unclear. The aim of this study was to determine the value of NIV and whether a parameter can predict the need for NIV in chronically critically ill patients during the weaning process. We conducted a prospective study that included chronically critically ill patients admitted to Spanish respiratory care units. The weaning method used consisted of progressive periods of spontaneous breathing trials...
October 2016: ERJ Open Research
https://www.readbyqxmd.com/read/28047432/su-g-iep1-11-resting-state-fluctuation-of-bold-signal-amplitude-for-mapping-cerebrovascular-reactivity-in-presurgical-functional-mri
#8
P Wang, P Hou, S Kesler, R Colen, A Kumar, S Prabhu, H Liu
PURPOSE: Cerebrovascular reactivity (CVR) MRI with hypercapnia challenges, such as a breath-hold (BH) task, has been proposed to indicate areas with neurovascular uncoupling potentials for presurgical functional MRI (fMRI). This study aimed to explore the use of resting-state (RS) fMRI, in particular, the RS fluctuation of amplitude (RSFA) for detecting the impaired CVR and compare with BH MRI in patients with gliomas. METHODS: The BH and RS fMRI from six patients as part of their presurgical fMRI studies were analyzed...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28044311/effects-of-hypercapnia-on-the-lung
#9
Masahiko Shigemura, Emilia Lecuona, Jacob I Sznajder
Gases are sensed by lung cells and can activate specific intracellular signaling pathways, and thus have physiologic and pathophysiologic effects. Carbon dioxide (CO2 ), a primary product of oxidative metabolism, can be sensed by eukaryotic cells eliciting specific responses via recently identified signaling pathways. However, the physiological and pathophysiological effects of high CO2 (hypercapnia) on the lungs and specific lung cells, which are the primary site of CO2 elimination, are incompletely understood...
January 3, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28038898/demographic-and-systemic-hemodynamic-influences-in-mechanisms-of-cerebrovascular-regulation-in-healthy-adults
#10
João Madureira, Pedro Castro, Elsa Azevedo
OBJECTIVES: A competent cerebrovascular regulation maintains an adequate cerebral blood flow by 3 major mechanisms: cerebral autoregulation (CA), vasomotor reactivity (VMR), namely to CO2, and neurovascular coupling (NVC). However, most studies generalize their results based on a response to a single parameter. Using a full battery of neurovascular stress tests, our study aims to evaluate the relationships among grades of CA, VMR, and NVC, and how their interplay is influenced by demographic and systemic hemodynamic factors...
December 27, 2016: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28034711/ventilatory-and-chemoreceptor-responses-to-hypercapnia-in-neonatal-rats-chronically-exposed-to-moderate-hyperoxia
#11
Ryan W Bavis, Ke-Yong Li, Kathryn J DeAngelis, Ryan J March, Josefine A Wallace, Sarah Logan, Robert W Putnam
Rats reared in hyperoxia hypoventilate in normoxia and exhibit progressive blunting of the hypoxic ventilatory response, changes which are at least partially attributed to abnormal carotid body development. Since the carotid body also responds to changes in arterial CO2/pH, we tested the hypothesis that developmental hyperoxia would attenuate the hypercapnic ventilatory response (HCVR) of neonatal rats by blunting peripheral and/or central chemoreceptor responses to hypercapnic challenges. Rats were reared in 21% O2 (Control) or 60% O2 (Hyperoxia) until studied at 4, 6-7, or 13-14days of age...
December 26, 2016: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28029639/sleep-disordered-breathing-exacerbates-muscle-vasoconstriction-and-sympathetic-neural-activation-in-patients-with-systolic-heart-failure
#12
Denise M L Lobo, Patricia F Trevizan, Edgar Toschi-Dias, Patricia A Oliveira, Rafael B Piveta, Dirceu R Almeida, Charles Mady, Edimar A Bocchi, Geraldo Lorenzi-Filho, Holly R Middlekauff, Carlos E Negrão
BACKGROUND: Sleep-disordered breathing (SDB) is common in patients with heart failure (HF), and hypoxia and hypercapnia episodes activate chemoreceptors stimulating autonomic reflex responses. We tested the hypothesis that muscle vasoconstriction and muscle sympathetic nerve activity (MSNA) in response to hypoxia and hypercapnia would be more pronounced in patients with HF and SDB than in patients with HF without SDB (NoSBD). METHODS AND RESULTS: Ninety consecutive patients with HF, New York Heart Association functional class II-III, and left ventricular ejection fraction ≤40% were screened for the study...
November 2016: Circulation. Heart Failure
https://www.readbyqxmd.com/read/28019021/multiparametric-estimation-of-brain-hemodynamics-with-mr-fingerprinting-asl
#13
Pan Su, Deng Mao, Peiying Liu, Yang Li, Marco C Pinho, Babu G Welch, Hanzhang Lu
PURPOSE: Assessment of brain hemodynamics without exogenous contrast agents is of increasing importance in clinical applications. This study aims to develop an MR perfusion technique that can provide noncontrast and multiparametric estimation of hemodynamic markers. METHODS: We devised an arterial spin labeling (ASL) method based on the principle of MR fingerprinting (MRF), referred to as MRF-ASL. By taking advantage of the rich information contained in MRF sequence, up to seven hemodynamic parameters can be estimated concomitantly...
December 26, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28011948/molecular-hydrogen-affords-neuroprotection-in-a-translational-piglet-model-of-hypoxic-ischemic-encephalopathy
#14
J Nemeth, V Toth-Szuki, V Varga, V Kovacs, G Remzso, F Domoki
Hypoxic-ischemic encephalopathy (HIE) is the major consequence of perinatal asphyxia (PA) in term neonates. Although the newborn piglet is an accepted large animal PA/HIE model, there is no consensus on PA-induction methodology to produce clinically relevant HIE. We aimed to create and to characterize a novel PA model faithfully reproducing all features of asphyxiation including severe hypercapnia resulting in HIE, and to test whether H2 is neuroprotective in this model. Piglets were anaesthetised, artificially ventilated, and intensively monitored (electroencephalography, core temperature, O2 saturation, arterial blood pressure and blood gases)...
October 2016: Journal of Physiology and Pharmacology: An Official Journal of the Polish Physiological Society
https://www.readbyqxmd.com/read/28007622/control-of-ventilation-in-health-and-disease
#15
REVIEW
Susmita Chowdhuri, M Safwan Badr
Control of ventilation occurs at different levels of the respiratory system via a negative feedback system that allows for precise regulation of levels of arterial carbon dioxide and oxygen. Mechanisms for ventilatory instability leading to sleep disordered breathing include changes in respiratory rhythm genesis and chemoresponsiveness to hypoxia and hypercapnia, cerebrovascular reactivity, abnormal chest wall and airway reflexes, and sleep state oscillations. One can potentially stabilize breathing during sleep-related breathing disorders by identifying one or more of these pathophysiological mechanisms...
December 19, 2016: Chest
https://www.readbyqxmd.com/read/28007319/nasal-flaring-as-a-clinical-sign-of-respiratory-acidosis-in-patients-with-dyspnea
#16
José Gregorio Zorrilla-Riveiro, Anna Arnau-Bartés, Ramón Rafat-Sellarés, Dolors García-Pérez, Arantxa Mas-Serra, Rafael Fernández-Fernández
OBJECTIVE: To determine whether the presence of nasal flaring is a clinical sign of respiratory acidosis in patients attending emergency departments for acute dyspnea. METHODS: Single-center, prospective, observational study of patients aged over 15 requiring urgent attention for dyspnea, classified as level II or III according to the Andorran Triage Program and who underwent arterial blood gas test on arrival at the emergency department. The presence of nasal flaring was evaluated by two observers...
December 10, 2016: American Journal of Emergency Medicine
https://www.readbyqxmd.com/read/28004411/non-chemosensitive-parafacial-neurons-simultaneously-regulate-active-expiration-and-airway-patency-under-hypercapnia-in-rats
#17
Alan A de Britto, Davi J A Moraes
Hypercapnia produces active expiration in rats and the recruitment of late-expiratory (late-E) neurons located in the parafacial Respiratory Group (pFRG) of the ventral medullary brainstem. We tested the hypothesis that hypercapnia produces active expiration and concomitant cranial respiratory motor responses controlling the oropharyngeal and upper airway patency by pFRG late-E neurons disinhibition, but not via synaptic excitation. Phrenic nerve, abdominal nerve (AbN), cranial respiratory motor nerves, subglottal pressure, and medullary and spinal neurons/motoneurons were recorded in in situ preparations of juvenile rats...
December 22, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/28004181/the-effect-of-aerosol-saline-on-laboratory-induced-dyspnea
#18
C R O'Donnell, R W Lansing, R M Schwartzstein, Robert Banzett
PURPOSE: In the 'placebo arm' of a recent study, we found that aerosol saline (sham treatment) produced substantial relief of laboratory-induced dyspnea (Breathing discomfort-BD) in nearly half the subjects. The sham intervention included a physiological change, and instructions to subjects could have produced expectation of dyspnea relief. In the present study, we attempted to discover whether the response to sham aerosol was driven by behavioral or physiological aspects of the intervention...
December 21, 2016: Lung
https://www.readbyqxmd.com/read/27999775/protective-ventilation-improves-gas-exchange-reduces-incidence-of-atelectases-and-affects-metabolic-response-in-major-pancreatoduodenal-surgery
#19
Vsevolod V Kuzkov, Ludmila N Rodionova, Yana Y Ilyina, Aleksey A Ushakov, Maria M Sokolova, Eugenia V Fot, Boris L Duberman, Mikhail Y Kirov
BACKGROUND: Protective perioperative ventilation has been shown to improve outcomes and reduce the incidence of postoperative pulmonary complications. The goal of this study was to assess the effects of ventilation with low tidal volume (VT) either alone or in a combination with moderate permissive hypercapnia in major pancreatoduodenal interventions. MATERIALS AND METHODS: Sixty adult patients scheduled for elective pancreatoduodenal surgery with duration >2 h were enrolled into a prospective single-center study...
2016: Frontiers in Medicine
https://www.readbyqxmd.com/read/27997923/the-role-of-hmgb1-in-pial-arteriole-dilating-reactivity-following-subarachnoid-hemorrhage-in-rats
#20
Haoliang Xu, Benjarat Changyaleket, Tibor Valyi-Nagy, Randal O Dull, Dale A Pelligrino, David E Schwartz, Zhao Zhong Chong
High-mobility group box 1 protein (HMGB1) has been implicated in inflammatory responses, and is also associated with cerebral vasospasm after subarachnoid hemorrhage (SAH). However, there are no direct evident links between HMGB1 and cerebral vasospasm. We therefore investigated the effects of HMGB1 on pial arteriole reactivity following SAH in rats. We initially found that SAH induced a significant decrease in pial arteriole dilating responses to sciatic nerve stimulation (SNS), hypercapnia (CO2), and the topical suffusion of acetylcholine (ACh), adenosine (ADO), and s-nitroso-N-acetylpenicillamine (SNAP) over a 7-day period after SAH...
December 21, 2016: Journal of Vascular Research
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