To investigate whether interstitialngedemaathighaltitude(HA)enhances airwayresponsiveness,westudied14healthysubjectsduringasojournatCapanna MargheritaonMonteRosa(4559m).Controlexperiments(CTRL)werecon- ducted inMilan(120m).AtHA,staticand dynamic complianceandrespiratory reactanceat5Hz(X5)weresignificantlydecreased(p<0.01forall),suggesting the occurrenceofinterstitiallungedema.Restingminuteventilation(VE)was increasedbyabout50%(p<0.001).Withinhalationofmethacholine,partialflow (Vpart)decreasedtovaluessimilartoCTRL(p>0.30)whereasmaximumflow decreasedless(p<0.02).AtHAlungresistanceatquietbreathing(RL)andat 5Hz (R5)increasedlessthanatCTRL(p<0.01forboth).Theeffectsofadeep breathonRLandR5weresimilartoCTRL.Duringincrementalmaximalexercise atHA,partgraduallyincreasedwithEataratesimilartoCTRL,butachieved highervaluesatpeakexerciseasaresultoftheincreasedmaximalVE(p<0.05). Inconclusion,controlofbronchialtoneatHAiswellpreserveddespitetheoccur- renceofinterstitiallungedema.Thismaybeduetothereducedgasdensityand hypoxia inducedhyperventilationwhichwouldopposeanyeffectsofanincrease in airwayresponsiveness.
Airway responsiveness to methacholine and exercise ataltitude in healthy humans
COGO, Annaluisa;POMIDORI, Luca;
2009
Abstract
To investigate whether interstitialngedemaathighaltitude(HA)enhances airwayresponsiveness,westudied14healthysubjectsduringasojournatCapanna MargheritaonMonteRosa(4559m).Controlexperiments(CTRL)werecon- ducted inMilan(120m).AtHA,staticand dynamic complianceandrespiratory reactanceat5Hz(X5)weresignificantlydecreased(p<0.01forall),suggesting the occurrenceofinterstitiallungedema.Restingminuteventilation(VE)was increasedbyabout50%(p<0.001).Withinhalationofmethacholine,partialflow (Vpart)decreasedtovaluessimilartoCTRL(p>0.30)whereasmaximumflow decreasedless(p<0.02).AtHAlungresistanceatquietbreathing(RL)andat 5Hz (R5)increasedlessthanatCTRL(p<0.01forboth).Theeffectsofadeep breathonRLandR5weresimilartoCTRL.Duringincrementalmaximalexercise atHA,partgraduallyincreasedwithEataratesimilartoCTRL,butachieved highervaluesatpeakexerciseasaresultoftheincreasedmaximalVE(p<0.05). Inconclusion,controlofbronchialtoneatHAiswellpreserveddespitetheoccur- renceofinterstitiallungedema.Thismaybeduetothereducedgasdensityand hypoxia inducedhyperventilationwhichwouldopposeanyeffectsofanincrease in airwayresponsiveness.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
