Effects of rapid saline infusion on lung mechanics and airway responsiveness in humans

Pellegrino, Riccardo; Dellacà, Raffaele L.; Macklem, Peter T.; Aliverti, Andréa; Bertini, S; Lotti, P; Agostoni, Piergiuseppe; Locatelli, Alessandro; Brusasco, Vito

doi:10.1152/japplphysiol.00310.2003

Cited by 49 publications

(47 citation statements)

References 29 publications

(38 reference statements)

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“…However, forced vital capacity decreased by 4.7%, but this change did not reach the level of statistical significance (p=0.09). Reduced expiratory flows were also evident following intravenous saline infusion in a previous study by our group and other previous studies (Cutillo, 1995;Pellegrino et al, 2003;Robertson et al, 2004), without any significant change in diffusing capacity of the lung (Robertson et al, 2004), suggesting the presence of peribronchial cuffing without significant fluid accumulation in the alveoli. Expiratory flow returned almost to baseline values after recovery measurements were acquired, suggesting that any peribronchial cuffing resulting from infusion was no longer significantly obstructing airways.…”

Section: Changes In Pulmonary Function and Impedance Cardiography Measupporting

confidence: 78%

Rapid Intravenous Infusion Of 20 ML/kg Saline Alters The Distribution Of Perfusion In Healthy Supine Humans

Henderson

Sá

Barash

et al. 2011

B68. Pulmonary Ventilation Dynamics: Novel Models, Images and Theories

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Rapid intravenous saline infusion, a model meant to replicate the initial changes leading to pulmonary interstitial edema, increases pulmonary arterial pressure in humans. We hypothesized that this would alter lung perfusion distribution. Six healthy subjects (29±6 years) underwent magnetic resonance imaging to quantify perfusion using arterial spin labeling. Regional proton density was measured using a fast-gradient echo sequence, allowing blood delivered to the slice to be normalized for density and quantified in mL/min/g. Contributions from flow in large conduit vessels were minimized using a flow cut-off value (blood delivered > 35% maximum in mL/min/ cm 3 ) in order to obtain an estimate of blood delivered to the capillary bed (perfusion). Images were acquired supine at baseline, after infusion of 20 mL/kg saline, and after a short upright recovery period for a single sagittal slice in the right lung during breath-holds at functional residual capacity. Thoracic fluid content measured by impedance cardiography was elevated postinfusion by up to 13% (p<0.0001). Forced expiratory volume in one second was reduced by 5.1% post-20 mL/kg (p=0.007). Infusion increased perfusion in nondependent lung by up to 16% (6.4±1.6mL/min/g baseline, 7.3±1.8 post, 7.4±1.7 recovery, p=0.03). Including conduit vessels, blood delivered in dependent lung was unchanged post-infusion; however, was increased at recovery (9.4±2.7 mL/min/g baseline, 9.7±2.0 post, 11.3±2.2 recovery, p=0.01). After accounting for changes in conduit vessels, there were no significant changes in perfusion in dependent lung following infusion (1.5±0.5 mL/min/g baseline, 1.5±0.4 post, 1.6±0.5, p=0.72). There were no significant changes in lung density. These data suggest that saline infusion increased perfusion to nondependent lung, consistent with an increase in intravascular pressures. Dependent lung may have been "protected" from increases in perfusion following infusion due to gravitational compression of the pulmonary vasculature. Keywordsarterial spin labeling; magnetic resonance imaging; pulmonary interstitial edema

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Section: Changes In Pulmonary Function and Impedance Cardiography Measupporting

confidence: 78%

Rapid Intravenous Infusion Of 20 ML/kg Saline Alters The Distribution Of Perfusion In Healthy Supine Humans

Henderson

Sá

Barash

et al. 2011

B68. Pulmonary Ventilation Dynamics: Novel Models, Images and Theories

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“…Indeed, the case-control difference suggests increased bronchial wall hysteresis, and therefore smooth muscle contraction, as mechanism to the EIB. Healthy children may exhibit small degree of airway narrowing after exercise not associated with dilatory effect of DI, and the mechanism put forward was transient hyperemia in the airway wall (17) based on the experimental report that rapid fluid loading of the latter promotes airway narrowing insensitive to DI (42).…”

Section: Discussionmentioning

confidence: 99%

Airway Response to Exercise by Forced Oscillations in Asthmatic Children

et al. 2010

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Forced expiratory volume in 1 s (FEV 1 ) detection of exercise-induced bronchoconstriction (EIB) to identify asthma has good specificity but rather low sensitivity. The aim was to test whether sensitivity may be improved by measuring respiratory resistance (RRS) by the forced oscillation technique (FOT). Forty-seven asthmatic and 50 control children (5-12 y) were studied before and after running 6 min on a treadmill. RRS in inspiration (RRSi) and expiration (RRSe), FEV 1 and RRSi response to a deep inhalation (DI) were measured before and after exercise. In asthmatics versus controls, exercise induced significantly larger increases in RRSi (p Ͻ 0.001) and larger decreases in FEV 1 (p ϭ 0.004). Asthmatics but not controls showed more bronchodilation by DI after exercise (p ϭ 0.02). At specificity Ͼ0.90, sensitivity was 0.53 with 25% increase RRSi and 0.45 with 27% increase RRSe or 5% decrease FEV 1 . It is concluded that the FOT improves sensitivity of exercise challenge, and the RRSi response to DI may prove useful in identifying the mechanism of airway obstruction. (Pediatr Res 68: 537-541, 2010) E xercise-induced bronchoconstriction (EIB) is closely linked to airway inflammation and unlikely to develop in healthy children (1), so that detecting airway hyperresponsiveness to exercise in the lung function laboratory is considered highly specific of asthma, i.e. it is associated with low rate of false-positive responses. A limitation is the rather low sensitivity of the test (2,3). EIB has been identified in primary school children by changes in forced expiratory volume in 1 s (FEV 1 ) or peak expiratory flow, and decision levels were mostly based on the former parameter (3). Respiratory resistance (RRS) measured by the forced oscillation technique (FOT) offers an alternative assessment of airway caliber, the time variations of which may be characterized for instance using a single excitation frequency (4). Computing RRS separately in inspiration and expiration (RRSi and RRSe, respectively) rather than over the whole breathing cycle may be of interest because the upper airways, which may represent a confounding factor in assessing the intrathoracic airways, are known to contribute differently to airway mechanics in inspiration and expiration (5,6). Furthermore, the RRS change in relation to volume history, more specifically the bronchomotor alteration that follows a deep inhalation (DI), has potential relevance in identifying the mechanism of EIB (7-9). Indeed, stretching the acutely contracted bronchial smooth muscle promotes bronchial wall relaxation, which in turn could be taken as an indicator of the magnitude of the airway response (10). To the best of our knowledge, a systematic analysis of diagnostic value of single-frequency RRS has not been performed during case-control identification of EIB in the lung function laboratory at school age.Therefore, the aim of this study was to assess the value of the FOT in identifying EIB in asthmatic children. More specifically, RRSi and RRSe and the change in...

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“…They concluded that the large subatmospheric pressures during deep inspiration may lead to extravasation of fluid in the inflamed asthmatic airway wall, thereby enhancing airway wall thickness. However, two studies using fast intravenous infusion of saline, resulting in airway wall thickening by edema and fluid flux (9,11), showed no effect on deep inspiration-induced bronchodilation (37).…”

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confidence: 99%

Enhanced airway dilation by positive-pressure inflation of the lungs compared with active deep inspiration in patients with asthma

Slats

Janssen²,

Jeu³

et al. 2008

Journal of Applied Physiology

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Effects of rapid saline infusion on lung mechanics and airway responsiveness in humans

Cited by 49 publications

References 29 publications

Rapid Intravenous Infusion Of 20 ML/kg Saline Alters The Distribution Of Perfusion In Healthy Supine Humans

Rapid Intravenous Infusion Of 20 ML/kg Saline Alters The Distribution Of Perfusion In Healthy Supine Humans

Airway Response to Exercise by Forced Oscillations in Asthmatic Children

Enhanced airway dilation by positive-pressure inflation of the lungs compared with active deep inspiration in patients with asthma

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