Evaluación de la broncodilataciónDr. Hernando SalaHospital Nacional A PosadasEl Palomar - Argentina

Saltos del MoconáRío Uruguay - MisionesArgentina

Curvas flujo-volumen máximos en un paciente asmático antes (línea llena) y después (línea discontinua) de la administración de un broncodilatador

Evaluación de la Broncodilatación

Diagrama esquemático del efecto agudo causado por la inhalación de un broncodilatador, en un paciente con asma de gravedad variable. La mejoría de FEV1 (línea discontinua) suele ser mayor cuando su valorar pre-broncodilatador está moderadamente reducido.

Relación entre FEV1 y la respuesta bronquial a la metacolina (PC20 mg ml –1) en pacientes con EPOC

CHANGES IN RESIDUAL AIR VOLUME AFTER THE USE OF BRONCHODILATOR AGENTS

KANAZIRSKI P, TSANEV B, BACHVAROV L.Probl Tuberk. 1963;41:77-81.

Olive and Hyatt 1978

Broncodilatación y DLCO

Effect of bronchodilatation on single breath pulmonary uptake of carbon monoxide in chronic obstructive pulmonary disease.

Baldi S, Fracchia C, Bruschi C, Dore R, Maestri R, Brusasco V, Pellegrino R.Int J Chron Obstruct Pulmon Dis. 2006;1(4):477-83.

Bronchoconstrictor effects of a deep inspiration in patients with asthma.Gayrard P, Orehek J, Grimaud C, CHarpin J.Am Rev Respir Dis. 1975 Apr;111(4):433-9.

• A deep inspiration from functional residual capacity to total lung capacity, performed at a low flow rate by a group of 40 unselected adult patients with asthma, yielded an immediate and transient increase (71 per cent, P smaller than 0.001) in specific airway resistance. In 2 of the 40, deep inspiration provoked an attack of asthma. The effect of deep inspiration can be attributed to a vagal bronchoconstrictor reflex, because it was prevented or decreased in most of the cases by inhalation of an anticholinergic drug. Beta-adrenergic blockade by propranolol potentiated in a minority of subjects the bronchoconstrictor response to deep inspiration. Deep expiration also induced a bronchoconstrictor effect, which was weaker than that of deep inspiration. It follows that functional studies of asthmatics may be biased if the technique requires maximal respiratory maneuvers.

Curvas V/V Parciales

Reversibility of the pulmonary function based on the partial flow-volume curve predicts the efficacy of bronchodilator therapy for treating chronic cough.

Nakade Y1, Fujimura M, Ohkura N, Nakata M, Nanbu Y, Oe H, Horita H, Sakai Y, Wada T.Intern Med. 2013;52(18):2017-23.

OBJECTIVE:Partial expiratory flow-volume curves have the potential to detect mild bronchoconstriction because they are not affected

by the modulatory effects of deep inspiration. The aim of this study was to investigate the relationship between the efficacy of bronchodilator therapy (BDT) in treating the cough and to assess the increase in the expiratory flow of the partial flow-volume curve at 40% above the residual volume level (PEF40) caused by treatment with a short-acting beta-2 agonist (SABA) in patients with chronic nonproductive cough.

METHODS:We measured the reversibility of PEF40 caused by a SABA in 42 patients with chronic nonproductive cough at visit 1 (day

0). The patients received BDT for six days. The visual analogue scale (VAS) was used to assess the efficacy of BDT in treating coughing at visit 2 (day 7) (0 mm, 'no cough;' 100 mm, 'no change in coughing').

RESULTS:Reversibility of the PEF40 was correlated (r=0.690, p<0.001) with the VAS score determined at visit 2 and was higher in the

patients with cough variant asthma (CVA) (44.9 ± 18.3%) than in those with atopic cough (13.4 ± 10.4%) (p<0.01).CONCLUSION:Reversibility of the PEF40 predicted the efficacy of BDT in patients with chronic nonproductive cough and helped to

identify patients with CVA.

• Airways flow resistance as a measure of the efficacy of inhalants in clinical drug trials.

• Cohen BM.• Helv Med Acta. 1969 Mar;34(6):455-67.

.

Forced oscillation technique vs spirometry to assess bronchodilatation in patients with asthma and COPD.Zerah F, et alChest. 1995 Jul;108(1):41-7

We conclude that the use of FOT can be considered as an alternative to forced expiration for detecting bronchodilatation in asthmatics and patients with COPD.

• Sensitivity of impulse oscillometry and spirometry in beta-blocker induced bronchoconstriction and beta-agonist bronchodilatation in asthma.

Short PM, Williamson PA, Lipworth BJ.

Ann Allergy Asthma Immunol. 2012 Dec;109(6):412-5.

Impulse oscillometry: interpretation and practical applications.Bickel S, Popler J, Lesnick B, Eid N.Chest. 2014 Sep 1;146(3):841-7.

FOT La mejor manera de medir la broncodilatación en población pediátrica

Monaldi Arch Chest Dis, 2001; 56:6, 555-582

Diagrama del diseño de un equipo para medir resistencia

Caja de madera

Circuito

Parlante

Malla

Tubo flexible

Transductores de presión

Neumotacógrafo Pieza bucal

Polígrafo

Amplificadores Convertidor A/D

PC

Transductor de presión Generador de

señal

Neumotac

Tubo flexible

Parlante

Caja

Señal de presión registrada en la boca

Señal de flujo

Presión

Flujo

Impedancia calculada

Monaldi Arch Chest Dis, 2001; 56:6, 555-582

R =Delta P/V

A partir del estudio de las presiones resultantes que se encuentran en fase y fuera de fase en relación con la señal se pueden calcular tanto la resistencia como la reactancia.

Inertancia

Elastancia

Resistencia

Reactancia

0

Impedancia del sistema respiratorio: es la suma de la resistencia y la reactancia

Zx = Rrs + Xrs

La reactancia es la suma de la elastanciay la inertancia, en electricidad capacitancia e inductancia respectivamente.

Xrs = XC + XL

Impedancia

Forced Oscillation Technique (FOT)

Aplicaciones Clínicas

Pruebas de broncodilatacióny broncoconstricción

No necesita inspiraciónprofunda ni espiraciónforzada

Meseta de SomuncuráPatagonia

Muchas Gracias

Inertancia

Elastancia

Resistencia

(Reactancia)

Frecuencia de resonancia

Los cambios de presión dependen solo de la resistencia

Impedancia