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

Slats, Annelies M.; Janssen, Kirsten; Jeu, Ronald C. de; Plas, Dirk T. van der; Schot, Robert; Aardweg, Joost G. van den; Sterk, Peter J.

doi:10.1152/japplphysiol.01237.2007

Cited by 9 publications

(5 citation statements)

References 46 publications

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“…This is supported by previous evidence that positive pressure of the lung enhanced bronchodilation of asthmatic patients (Slats et al. ) and that using CPAP reduced airway responsiveness in an allergen‐induced rabbit model for asthma. This research extends out from these findings to see whether the two actions of a prestretch and SILO have an additive nature; will they improve each other's effect or not?…”

Section: Discussionsupporting

confidence: 80%

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Prestretched airway smooth muscle response to length oscillation

Al‐Jumaily

Roos

Bessaguet

et al. 2017

Physiological Reports

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Airway smooth muscle (ASM) hyperconstriction is the cause of many respiratory diseases including asthma. In vitro testing has demonstrated that the active forces of ASM are reduced by length oscillation (LO) mimicking tidal breathing. In a previous study, we demonstrated that this force reduction can be further enhanced when superimposing oscillations (with certain frequencies and amplitudes) on this LO. In contrast, it has been reported that pressurizing the lung may help in relieving asthmatic airway constrictions. Ultimately, this pressurizing stretches the ASM and may disturb the acto‐myosin cross‐bridges in a manner similar to LO; however, it is of a static rather than dynamic nature. This research investigates the effect of combining both prestretch‐ and LO‐applications on contracted porcine ASM. Isolated porcine ASM relaxation was tested with a 0.56%, 2%, or 4% stretch of its reference length (L ref) in addition to LO. These oscillations are composed of a main wave mimicking the normal breathing (frequency of 0.33 Hz and amplitude of 4% L ref) and superimposed oscillations (frequencies of 20, 30, 40, 60 and 80 Hz and amplitude of 1% L ref). The oscillations were maintained for 10 min. The results demonstrate that a prestretch of 0.56% and 2% L ref does enhance the contracted ASM relaxation at certain superimposed length oscillations frequencies while of 4% L ref does not.

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Section: Discussionsupporting

confidence: 80%

“…Later, Slats et al. () reported that positive‐pressure inflation of the lungs enhanced the bronchodilation of asthmatic patients' airways compared with active DI. These findings indicate that the way in which mechanical strains and their durations are applied on the airway have a determinant effect on airway responsiveness.…”

Section: Introductionmentioning

confidence: 99%

Prestretched airway smooth muscle response to length oscillation

Al‐Jumaily

Roos

Bessaguet

et al. 2017

Physiological Reports

View full text Add to dashboard Cite

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“…Moreover, it has been recognised that inhalations to total lung capacity are broncho-protective, particularly in subjects with borderline AHR and non-asthmatics [34]. However, it has also been shown, that in asthmatics with mild AHR, deep inhalations do not produce a significantly lower response to MCH [37, 47] than tidal breathing [40]. …”

Section: Discussionmentioning

confidence: 99%

Diagnostic accuracy of methacholine challenge tests assessing airway hyperreactivity in asthmatic patients - a multifunctional approach

et al. 2016

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BackgroundThere are few studies comparing diagnostic accuracy of different lung function parameters evaluating dose–response characteristics of methacholine (MCH) challenge tests (MCT) as quantitative outcome of airway hyperreactivity (AHR) in asthmatic patients. The aim of this retrospectively analysis of our database (Clinic Barmelweid, Switzerland) was, to assess diagnostic accuracy of several lung function parameters quantitating AHR by dose–response characteristics.MethodsChanges in effective specific airway conductance (sGeff) as estimate of the degree of bronchial obstruction were compared with concomitantly measured forced expiratory volume in 1 s (FEV1) and forced expiratory flows at 50% forced vital capacity (FEF50). According to the GINA Guidelines the patients (n = 484) were classified into asthmatic patients (n = 337) and non-asthmatic subjects (n = 147). Whole-body plethysmography (CareFusion, Würzburg, Germany) was performed using ATS-ERS criteria, and for the MCTs a standardised computer controlled protocol with 3 consecutive cumulative provocation doses (PD1: 0.2 mg; PD2: 1.0 mg; PD3: 2.2 mg) was used. Break off criterion for the MCTs were when a decrease in FEV1 of 20% was reached or respiratory symptoms occurred.ResultsIn the assessment of AHR, whole-body plethysmography offers in addition to spirometry indices of airways conductance and thoracic lung volumes, which are incorporated in the parameter sGeff, derived from spontaneous tidal breathing. The cumulative percent dose-responses at each provocation step were at the 1st level step (0.2 mg MCH) 3.7 times, at the 2nd level step (1 mg MCH) 2.4 times, and at the 3rd level step (2.2 mg MCH) 2.0 times more pronounced for sGeff, compared to FEV1. A much better diagnostic odds ratio of sGeff (7.855) over FEV1 (6.893) and FEF50 (4.001) could be found. Moreover, the so-called dysanapsis, and changes of end-expiratory lung volume were found to be important determinants of AHR.ConclusionsApplying plethysmographic tidal breathing analysis in addition to spirometry in MCTs provides relevant advantages. The absence of deep and maximal inhalations and forced expiratory manoeuvres improve the subject’s cooperation and coordination, and provide sensitive and differentiated test results, improving diagnostic accuracy. Moreover, by the combined assessment, pulmonary hyperinflation and dysanapsis can be respected in the differentiation between “asthmatics” and “non-asthmatics”.Electronic supplementary materialThe online version of this article (doi:10.1186/s12931-016-0470-0) contains supplementary material, which is available to authorized users.

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“…Finally, there might be a role for the CPAP to assist in the inhalation therapy. As ventilation inhomogeneities are minimized at maximum lung inflation in both asthma (2,22) and chronic obstructive pulmonary disease (1), the CPAP could be used to improve the deposition of bronchoactive agents within the lung regions that receive little medications with the conventional inhalation techniques because of severe narrowing of the subtending airways.…”

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confidence: 99%