scholarly journals Idiopathic scoliosis. Gas exchange and the age dependence of arterial blood gases.

1976 ◽  
Vol 58 (4) ◽  
pp. 825-833 ◽  
Author(s):  
E R Kafer
Keyword(s):  
Gas Exchange ◽  
Idiopathic Scoliosis ◽  
Blood Gases ◽  
Age Dependence ◽  
Arterial Blood Gases ◽  
Arterial Blood

Validation of measurements of ventilation-to-perfusion ratio inequality in the lung from expired gas

2003 ◽  
Vol 94 (3) ◽  
pp. 1186-1192 ◽  
Author(s):  
G. Kim Prisk ◽  
Harold J. B. Guy ◽  
John B. West ◽  
James W. Reed
Keyword(s):  
Gas Exchange ◽  
Respiratory Exchange Ratio ◽  
Blood Gases ◽  
Inert Gas ◽  
Phase Iii ◽  
Strongly Correlated ◽  
Arterial Blood Gases ◽  
Arterial Blood ◽  
Expired Gas ◽  
The Relationship

The analysis of the gas in a single expirate has long been used to estimate the degree of ventilation-perfusion (V˙a/Q˙) inequality in the lung. To further validate this estimate, we examined three measures ofV˙a/Q˙ inhomogeneity calculated from a single full exhalation in nine anesthetized mongrel dogs under control conditions and after exposure to aerosolized methacholine. These measurements were then compared with arterial blood gases and with measurements of V˙a/Q˙ inhomogeneity obtained using the multiple inert gas elimination technique. The slope of the instantaneous respiratory exchange ratio (R slope) vs. expired volume was poorly correlated with independent measures, probably because of the curvilinear nature of the relationship due to continuing gas exchange. When R was converted to the intrabreathV˙a/Q˙ (iV˙/Q˙), the best index was the slope of iV˙/Q˙ vs. volume over phase III (iV˙/Q˙slope). This was strongly correlated with independent measures, especially those relating to inhomogeneity of perfusion. The correlations for iV˙/Q˙ slope and R slope considerably improved when only the first half of phase III was considered. We conclude that a useful noninvasive measurement ofV˙a/Q˙ inhomogeneity can be derived from the intrabreath respiratory exchange ratio.

Arterial Blood Gases, Acid-Base Balance, and Lactate and Gas Exchange Variables During Hypoxic Exercise

1989 ◽  
Vol 10 (04) ◽  
pp. 279-285 ◽  
Author(s):  
T. Yoshida ◽  
M. Udo ◽  
M. Chida ◽  
K. Makiguchi ◽  
M. Ichioka ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Blood Gases ◽  
Arterial Blood Gases ◽  
Acid Base Balance ◽  
Acid Base ◽  
Arterial Blood ◽  
Base Balance ◽  
Hypoxic Exercise

scholarly journals Tidal Volume, Lung Hyperinflation and Arterial Oxygenation during General Anaesthesia

1993 ◽  
Vol 21 (6) ◽  
pp. 806-810 ◽  
Author(s):  
W. A. Tweed ◽  
W. T. Phua ◽  
K. Y. Chong ◽  
E. Lim ◽  
T. L. Lee
Keyword(s):  
Gas Exchange ◽  
Tidal Volume ◽  
General Anaesthesia ◽  
Blood Gases ◽  
Arterial Oxygenation ◽  
Arterial Blood Gases ◽  
Controlled Ventilation ◽  
Arterial Blood ◽  
Patients At Risk ◽  
Induction Of Anaesthesia

Impaired pulmonary oxygen (O2) exchange is common during general anaesthesia but there is no clinical unanimity as to methods of prevention or treatment. We studied 14 patients at risk for pulmonary dysfunction because of increased age, obesity, cigarette smoking, or chronic lung disease. Pulmonary O2 exchange was measured during four conditions of ventilation: awake spontaneous, conventional tidal volume (CVT, 7 ml.kg-1) or high tidal volume (HVT, 12 ml.kg-1) controlled ventilation, and five min after manual hyperinflation (H1) of the lungs. The F1O2 was controlled at 0.5, and FETCO2 was kept constant by adding dead space during HVT. Eight patients were ventilated with N2O/O2 and six with air/O2. Arterial blood gases were used to calculate the (A-a)DO2. In seven patients (A-a)DO2 worsened after induction of anaesthesia, while in seven there was no change or an improvement. Manual HI significantly reduced (A-a)DO2, but changing tidal volume (VT) had no effect. Using a multivariate model to predict O2 exchange, obesity and type of surgery were significantly associated with worsening, while level of VT and inspiratory gas (N2O or N2) were not significant predictors. Thus patient and surgical factors were more important determinants of pulmonary gas exchange during anaesthesia than were tidal volume or inspiratory gas. Manual HI is a simple and effective manoeuvre to improve gas exchange.

scholarly journals Do We Need Exercise Tests to Detect Gas Exchange Impairment in Fibrotic Idiopathic Interstitial Pneumonias?

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Benoit Wallaert ◽  
Lidwine Wemeau-Stervinou ◽  
Julia Salleron ◽  
Isabelle Tillie-Leblond ◽  
Thierry Perez
Keyword(s):  
Gas Exchange ◽  
Cardiopulmonary Exercise Testing ◽  
Blood Gases ◽  
Oxygen Desaturation ◽  
Walk Test ◽  
Diffusing Capacity ◽  
Arterial Blood Gases ◽  
Exercise Tests ◽  
Cardiopulmonary Exercise ◽  
Arterial Blood

In patients with fibrotic idiopathic interstitial pneumonia (f-IIP), the diffusing capacity for carbon monoxide (DLCO) has been used to predict abnormal gas exchange in the lung. However, abnormal values for arterial blood gases during exercise are likely to be the most sensitive manifestations of lung disease. The aim of this study was to compare DLCO, resting PaO2, P(A-a)O2at cardiopulmonary exercise testing peak, and oxygen desaturation during a 6-min walk test (6MWT). Results were obtained in 121 patients with idiopathic pulmonary fibrosis (IPF,n=88) and fibrotic nonspecific interstitial pneumonias (NSIP,n=33). All but 3 patients (97.5%) had low DLCO values (<LLN) whereas only 66.6% had low KCO; 42 patients (65%) exhibited resting hypoxemia (<75 mmHg); 112 patients (92.5%) exhibited a high P[(A-a)O2], peak (>35 mmHg) and 100 (83%) demonstrated significant oxygen desaturation during 6MWT (>4%). Interestingly 27 patients had low DLCO and normal P(A-a)O2, peak and/or no desaturation during the 6MWT. The 3 patients with normal DLCO also had normal PaO2, normal P(A-a)O2, peak, and normal oxygen saturation during 6MWT. Our results demonstrate that in fibrotic IIP, DLCO better defines impairment of pulmonary gas exchange than resting PaO2, exercise P(A-a)O2, peak, or 6MWT SpO2.

scholarly journals Noninvasive measurement of pulmonary gas exchange: comparison with data from arterial blood gases

2019 ◽  
Vol 316 (1) ◽  
pp. L114-L118 ◽  
Author(s):  
John B. West ◽  
Daniel L. Wang ◽  
G. Kim Prisk ◽  
Janelle M. Fine ◽  
Amy Bellinghausen ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Blood Gases ◽  
Normal Subjects ◽  
Pulmonary Gas Exchange ◽  
Oxygen Deficit ◽  
Noninvasive Method ◽  
Arterial Blood Gases ◽  
Noninvasive Technique ◽  
Arterial Blood ◽  
End Tidal

A new noninvasive method was used to measure the impairment of pulmonary gas exchange in 34 patients with lung disease, and the results were compared with the traditional ideal alveolar-arterial Po2 difference (AaDO2) calculated from arterial blood gases. The end-tidal Po2 was measured from the expired gas during steady-state breathing, the arterial Po2 was derived from a pulse oximeter if the [Formula: see text] was 95% or less, which was the case for 23 patients. The difference between the end-tidal and the calculated Po2 was defined as the oxygen deficit. Oxygen deficit was 42.7 mmHg (SE 4.0) in this group of patients, much higher than the means previously found in 20 young normal subjects measured under hypoxic conditions (2.0 mmHg, SE 0.8) and 11 older normal subjects (7.5 mmHg, SE 1.6) and emphasizes the sensitivity of the new method for detecting the presence of abnormal gas exchange. The oxygen deficit was correlated with AaDO2 ( R2 0.72). The arterial Po2 that was calculated from the noninvasive technique was correlated with the results from the arterial blood gases ( R2 0.76) and with a mean bias of +2.7 mmHg. The Pco2 was correlated with the results from the arterial blood gases (R2 0.67) with a mean bias of −3.6 mmHg. We conclude that the oxygen deficit as obtained from the noninvasive method is a very sensitive indicator of impaired pulmonary gas exchange. It has the advantage that it can be obtained within a few minutes by having the patient simply breathe through a tube.

scholarly journals SARS-CoV-2 pneumonia succesfully treated with cpap and cycles of tripod position: a case report

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Michela Rauseo ◽  
Lucia Mirabella ◽  
Rosa Roberta Caporusso ◽  
Leonarda Pia Cantatore ◽  
Marco Paolo Perrini ◽  
...  
Keyword(s):  
Respiratory Failure ◽  
Gas Exchange ◽  
Ventilatory Support ◽  
Blood Gases ◽  
Normal Lung ◽  
Prone Positioning ◽  
Arterial Blood Gases ◽  
Hypoxemic Respiratory Failure ◽  
Unsuccessful Attempt ◽  
Arterial Blood

Abstract Background Pneumonia induced by 2019 Coronavirus (COVID-19) is characterized by hypoxemic respiratory failure that may present with a broad spectrum of clinical phenotypes. At the beginning, patients may have normal lung compliance and be responsive to noninvasive ventilatory support, such as CPAP. However, the transition to more severe respiratory failure - Severe Acute Respiratory Syndrome (SARS-CoV-2), necessitating invasive ventilation is often abrupt and characterized by a severe V/Q mismatch that require cycles of prone positioning. The aim of this case is to report the effect on gas exchange, respiratory mechanics and hemodynamics of tripod (or orthopneic sitting position) used as an alternative to prone position in a patient with mild SARS-CoV-2 pneumonia ventilated with helmet CPAP. Case presentation A 77-year-old awake and collaborating male patient with mild SARS-CoV-2 pneumonia and ventilated with Helmet CPAP, showed sudden worsening of gas exchange without dyspnea. After an unsuccessful attempt of prone positioning, we alternated three-hours cycles of semi-recumbent and tripod position, still keeping him in CPAP. Arterial blood gases (PaO2/FiO2, PaO2, SaO2, PaCO2 and A/a gradient), respiratory (VE, VT, RR) and hemodynamic parameters (HR, MAP) were collected in the supine and tripod position. Cycles of tripod position were continued for 3 days. The patient had a clinically important improvement in arterial blood gases and respiratory parameters, with stable hemodynamic and was successfully weaned and discharged to ward 10 days after pneumonia onset. Conclusions Tripod position during Helmet CPAP can be applied safely in patients with mild SARS-CoV-2 pneumonia, with improvement of oxygenation and V/Q matching, thus reducing the need for intubation.

scholarly journals Pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest

2020 ◽  
Vol 8 (S1) ◽  
Author(s):  
Chiara Robba ◽  
Dorota Siwicka-Gieroba ◽  
Andras Sikter ◽  
Denise Battaglini ◽  
Wojciech Dąbrowski ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Mechanical Ventilation ◽  
Cardiac Arrest ◽  
Oxygen Demand ◽  
Blood Gases ◽  
Metabolic Energy ◽  
High Morbidity ◽  
Arterial Blood Gases ◽  
Arterial Blood ◽  
Clinical Consequences

AbstractPost cardiac arrest syndrome is associated with high morbidity and mortality, which is related not only to a poor neurological outcome but also to respiratory and cardiovascular dysfunctions. The control of gas exchange, and in particular oxygenation and carbon dioxide levels, is fundamental in mechanically ventilated patients after resuscitation, as arterial blood gases derangement might have important effects on the cerebral blood flow and systemic physiology.In particular, the pathophysiological role of carbon dioxide (CO2) levels is strongly underestimated, as its alterations quickly affect also the changes of intracellular pH, and consequently influence metabolic energy and oxygen demand. Hypo/hypercapnia, as well as mechanical ventilation during and after resuscitation, can affect CO2 levels and trigger a dangerous pathophysiological vicious circle related to the relationship between pH, cellular demand, and catecholamine levels. The developing hypocapnia can nullify the beneficial effects of the hypothermia. The aim of this review was to describe the pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest.According to our findings, the optimal ventilator strategies in post cardiac arrest patients are not fully understood, and oxygen and carbon dioxide targets should take in consideration a complex pattern of pathophysiological factors. Further studies are warranted to define the optimal settings of mechanical ventilation in patients after cardiac arrest.

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