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Alkalosis and hypercapnia

Michael Brannen, Kathleen M Gilmour
Rainbow trout ( Oncorhynchus mykiss ) exposed to acid-base challenges activate branchial mechanisms for the excretion of acid-base equivalents. Current models of branchial acid-base excretion in freshwater rainbow trout propose two main ionocyte types: the peanut lectin agglutinin-positive (PNA+ ) mitochondrion-rich cell or ionocyte is believed to secrete HCO3 - in exchange for Cl- , whereas H+ secretion is thought to occur across PNA- ionocytes in exchange for Na+ Both HCO3 - and H+ are supplied by intracellular hydration of CO2 catalysed by cytosolic carbonic anhydrase (CAc)...
March 12, 2018: Journal of Experimental Biology
Alyssa M Weinrauch, Alexander M Clifford, Greg G Goss
Hagfishes are unique to the vertebrate lineage in that they acquire dissolved nutrients across multiple epithelia including the intestine, gill, and skin. This feat has been attributed to their immersive feeding behavior that likely simultaneously provides benefits (nutrient rich) and potentially adverse (hypercapnia, hypoxia, high environmental ammonia) physiological effects. Examinations have been conducted of the ex vivo transport capabilities of specific nutrients as well as in vivo effects of the hypothesized feeding environments, yet the physiological effects of feeding itself have never been elucidated...
January 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Alfonso Schiavo, Maurizio Renis, Mario Polverino, Arcangelo Iannuzzi, Francesca Polverino
BACKGROUND: Hypoventilation produces or worsens respiratory acidosis in patients with hypercapnia due to acute exacerbations of chronic obstructive pulmonary disease (AECOPD). In these patients acid-base and hydroelectrolite balance are closely related. Aim of the present study was to evaluate acid-base and hydroelectrolite alterations in these subjects and the effect of non-invasive ventilation and pharmacological treatment. METHODS: We retrospectively analysed 110 patients consecutively admitted to the Internal Medicine ward of Cava de' Tirreni Hospital for acute exacerbation of hypercapnic chronic obstructive pulmonary disease...
2016: Multidisciplinary Respiratory Medicine
Constantine A Manthous, Babak Mokhlesi
The prevalence of obesity hypoventilation syndrome and obstructive sleep apnea are increasing rapidly in the United States in parallel with the obesity epidemic. As the pathogenesis of this chronic illness is better understood, effective evidence-based therapies are being deployed to reduce morbidity and mortality. Nevertheless, patients with obesity hypoventilation still fall prey to at least four avoidable types of therapeutic errors, especially at the time of hospitalization for respiratory or cardiovascular decompensation: (1) patients with obesity hypoventilation syndrome may develop acute hypercapnia in response to administration of excessive supplemental oxygen; (2) excessive diuresis for peripheral edema using a loop diuretic such as furosemide exacerbates metabolic alkalosis, thereby worsening daytime hypoventilation and hypoxemia; (3) excessive or premature pharmacological treatment of psychiatric illnesses can exacerbate sleep-disordered breathing and worsen hypercapnia, thereby exacerbating psychiatric symptoms; and (4) clinicians often erroneously diagnose obstructive lung disease in patients with obesity hypoventilation, thereby exposing them to unnecessary and potentially harmful medications, including β-agonists and corticosteroids...
January 2016: Annals of the American Thoracic Society
Tyler M Basting, Peter G R Burke, Roy Kanbar, Kenneth E Viar, Daniel S Stornetta, Ruth L Stornetta, Patrice G Guyenet
In conscious mammals, hypoxia or hypercapnia stimulates breathing while theoretically exerting opposite effects on central respiratory chemoreceptors (CRCs). We tested this theory by examining how hypoxia and hypercapnia change the activity of the retrotrapezoid nucleus (RTN), a putative CRC and chemoreflex integrator. Archaerhodopsin-(Arch)-transduced RTN neurons were reversibly silenced by light in anesthetized rats. We bilaterally transduced RTN and nearby C1 neurons with Arch (PRSx8-ArchT-EYFP-LVV) and measured the cardiorespiratory consequences of Arch activation (10 s) in conscious rats during normoxia, hypoxia, or hyperoxia...
January 14, 2015: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
María M Adeva-Andany, Carlos Fernández-Fernández, David Mouriño-Bayolo, Elvira Castro-Quintela, Alberto Domínguez-Montero
Metabolic acidosis occurs when a relative accumulation of plasma anions in excess of cations reduces plasma pH. Replacement of sodium bicarbonate to patients with sodium bicarbonate loss due to diarrhea or renal proximal tubular acidosis is useful, but there is no definite evidence that sodium bicarbonate administration to patients with acute metabolic acidosis, including diabetic ketoacidosis, lactic acidosis, septic shock, intraoperative metabolic acidosis, or cardiac arrest, is beneficial regarding clinical outcomes or mortality rate...
2014: TheScientificWorldJournal
Lisa M K Chin, George J F Heigenhauser, Donald H Paterson, John M Kowalchuk
Pulmonary O2 uptake (V(O₂p)) and leg blood flow (LBF) kinetics were examined at the onset of moderate-intensity exercise, during hyperventilation with and without associated hypocapnic alkalosis. Seven male subjects (25 ± 6 years old; mean ± SD) performed alternate-leg knee-extension exercise from baseline to moderate-intensity exercise (80% of estimated lactate threshold) and completed four to six repetitions for each of the following three conditions: (i) control [CON; end-tidal partial pressure of CO2 (P(ET, CO₂)) ~40 mmHg], i...
December 2013: Experimental Physiology
Guillermo A Raimondi, Silvia Gonzalez, Jorge Zaltsman, Guillermo Menga, Horacio J Adrogué
BACKGROUND AND OBJECTIVES: Acid-base status in acute severe asthma (ASA) remains undefined; some studies report complete absence of metabolic acidosis, whereas others describe it as present in one fourth of patients or more. Conclusion discrepancies would therefore appear to derive from differences in assessment methodology. Only a systematic approach centering on patient clinical findings can correctly establish true acid-base disorder prevalence levels. METHODS: This study examines acid-base patterns in ASA (314 patients), taking into account both natural history of disease and treatment, in patients free of other diseases altering acid-base status...
December 2013: Journal of Asthma: Official Journal of the Association for the Care of Asthma
Richard Windsor, Will Petchey
No abstract text is available yet for this article.
May 2, 2013: BMJ: British Medical Journal
Pietro L'Abate, Susanne Wiegert, Joachim Struck, Sven Wellmann, Vincenzo Cannizzaro
Copeptin, the C-terminal part of the arginine vasopressin precursor peptide, holds promise as a diagnostic and prognostic plasma biomarker in various acute clinical conditions. Factors influencing copeptin response in the critical care setting are only partially established and have not been investigated systematically. Using an in vivo infant ventilation model (Wistar rats, 14 days old), we studied the influence of commonly occurring stressors in critically ill children. In unstressed ventilated rats basal median copeptin concentration was 22pmol/L...
January 15, 2013: Respiratory Physiology & Neurobiology
Casey A Mueller, Hiroshi Tazawa, Warren W Burggren
In day 15 chicken embryos, we determined the time course responses of acid-base balance and hematological respiratory variables during 24h exposure to 15, 20, 40 or 90% O(2), in the presence of 5% CO(2). Hypercapnic respiratory acidosis was initially (2h) only slightly (∼20%) compensated by metabolic alkalosis in normoxic/hyperoxic embryos. After 6h, respiratory acidosis was partially (∼40-50%) compensated not only in normoxic/hyperoxic embryos, but also in hypoxic embryos. However, partial metabolic compensation in 15% O(2) could not be preserved after 24h...
January 15, 2013: Respiratory Physiology & Neurobiology
L DeLuca, I Holzman, K Gibbs
This is a case of a neonate born with a respiratory acidosis with a compensatory metabolic alkalosis. This case demonstrates placental physiology of gas exchange as well as the blunted ventilatory response in the neonate from chronic hypercapnia.
October 2012: Journal of Perinatology: Official Journal of the California Perinatal Association
Claudio Terzano, Fabio Di Stefano, Vittoria Conti, Marta Di Nicola, Gregorino Paone, Angelo Petroianni, Alberto Ricci
BACKGROUND: Hypercapnic Chronic Obstructive Pulmonary Disease (COPD) exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV) when treating hypercapnic respiratory failure. METHODS: Sixty-seven consecutive patients who were hospitalized for hypercapnic COPD exacerbation had their clinical condition, respiratory function, blood chemistry, arterial blood gases, blood lactate and volemic state assessed...
2012: PloS One
Mohamed M Helmy, Else A Tolner, Sampsa Vanhatalo, Juha Voipio, Kai Kaila
OBJECTIVE: The mechanisms whereby birth asphyxia leads to generation of seizures remain unidentified. To study the possible role of brain pH changes, we used a rodent model that mimics the alterations in systemic CO(2) and O(2) levels during and after intrapartum birth asphyxia. METHODS: Neonatal rat pups were exposed for 1 hour to hypercapnia (20% CO(2) in the inhaled gas), hypoxia (9% O(2)), or both (asphyxic conditions). CO(2) levels of 10% and 5% were used for graded restoration of normocapnia...
March 2011: Annals of Neurology
Nicolaos E Madias
Respiratory acid-base disorders are those abnormalities in acid-base equilibrium that are expressed as primary changes in the arterial carbon dioxide tension (PaCO2). An increase in PaCO2 (hypercapnia) acidifies body fluids and initiates the acid-base disturbance known as respiratory acidosis. By contrast, a decrease in PaCO2 (hypocapnia) alkalinizes body fluids and initiates the acid-base disturbance known as respiratory alkalosis. The impact on systemic acidity of these primary changes in PaCO2 is ameliorated by secondary, directional changes in plasma [HCO3¯] that occur in 2 stages...
November 2010: Journal of Nephrology
Mark A Powers
No abstract text is available yet for this article.
November 2010: Respiratory Care
Joan-Maria Raurich, Gemma Rialp, Jordi Ibáñez, Juan Antonio Llompart-Pou, Ignacio Ayestarán
OBJECTIVE: In obesity-hypoventilation-syndrome patients mechanically ventilated for hypercapnic respiratory failure we investigated the relationship between CO₂ response, body mass index, and plasma bicarbonate concentration, and the effect of acetazolamide on bicarbonate concentration and CO₂ response. METHODS: CO₂ response tests and arterial blood gas analysis were performed in 25 patients ready for a spontaneous breathing test, and repeated in a subgroup of 8 patients after acetazolamide treatment...
November 2010: Respiratory Care
Steve F Perry, Marvin H Braun, Janet Genz, Branka Vulesevic, Josi Taylor, Martin Grosell, Kathleen M Gilmour
The plainfin midshipman (Porichthys notatus) possesses an aglomerular kidney and like other marine teleosts, secretes base into the intestine to aid water absorption. Each of these features could potentially influence acid-base regulation during respiratory acidosis either by facilitating or constraining HCO(3)(-) accumulation, respectively. Thus, in the present study, we evaluated the capacity of P. notatus to regulate blood acid-base status during exposure to increasing levels of hypercapnia (nominally 1-5% CO(2))...
November 2010: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
I-Chun Chuang, Huei-Ping Dong, Rei-Cheng Yang, Tung-Heng Wang, Jen-Hsiang Tsai, Pei-Hsuan Yang, Ming-Shyan Huang
There have been contradictory reports suggesting that CO(2) may constrict, dilate, or have no effect on pulmonary vessels. Permissive hypercapnia has become a widely adopted ventilatory technique used to avoid ventilator-induced lung injury, particularly in patients with acute respiratory distress syndrome (ARDS). On the other hand, respiratory alkalosis produced by mechanically induced hyperventilation is the mainstay of treatment for newborn infants with persistent pulmonary hypertension. It is important to clarify the vasomotor effect of CO(2) on pulmonary circulation in order to better evaluate the strategies of mechanical ventilation in intensive care...
June 2010: Lung
Amit Banga, G C Khilnani
Posthypercapnic alkalosis (PHA) is frequently overlooked as a complication of mechanical ventilation in patients with exacerbation of chronic obstructive pulmonary disease (COPD). The current study was conducted to determine the incidence, risk factors for development and effect on outcome of PHA. Eighty-four patients (62 +/- 11 years, range 42-78 years, M:F 58: 26) with exacerbation of COPD with underlying chronic hypercapnic respiratory failure requiring mechanical ventilation were included in a retrospective fashion...
December 2009: COPD
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