Effect of the Buteyko Method on Resting Ventilation and Asthma Control in Asthma Patients Monique van Oosten Ritgerð til meistaragráðu Háskóli Íslands Læknadeild Námsbraut í Lýðheilsuvísindum Heilbrigðisvísindasvið Áhrif Buteyko aðferðinnar á hvíldaröndun og stjórnun astmasjúkdómsins hjá astmasjúklingum Monique van Oosten Ritgerð til meistaragráðu í Lýðheilsuvísindum Leiðbeinandi: Marta Guðjónsdóttir Meistaranámsnefnd: Marta Guðjónsdóttir, Auðna Ágústsdóttir og Björn Magnússon Læknadeild Námsbraut í Lýðheilsuvísindum Heilbrigðisvísindasvið Háskóla Íslands Mars 2017 Effect of the Buteyko Method on Resting Ventilation and Asthma Control in Asthma Patients Monique van Oosten Thesis for the degree of Master of Science Supervisor: Marta Guðjónsdóttir Masters committee: Marta Guðjónsdóttir, Auðna Ágústsdóttir and Björn Magnússon Faculty of Medicine Department of Public Health School of Health Sciences March 2017 Ritgerð þessi er til meistaragráðu í lýðheilsufræði og er óheimilt að afrita ritgerðina á nokkurn hátt nema með leyfi rétthafa. © Monique van Oosten 2017 Prentun: Háskólaprent Reykjavík, Ísland 2017 Ágrip Bakgrunnur . Buteyko meðferðin (BM) virðist breyta öndun, bæta lífsgæði og astma stjórnun hjá astma sjúklingum. Rannsóknir hafa fram að þessu ekki skilgreint nægilega vel lífeðlisfræðileg áhrif meðferðarinnar. Markmið þessarar rannsóknar er að skoða lífeðlisfræðileg áhrif BM á hvíldaröndun og stjórnun astma í hóp astmasjúklinga. Aðferð . Í þessari framskyggnu, íhlutandi rannsókn með samanburðarhópi voru astmasjúklingar mældir þrisvar sinnum í algjörri hvíld, með 6 mánaða millibili. Þeir voru paraðir miðað við aldur, kyn og líkamsþyngdarstuðul (BMI) við heilbrigðan samanburðahóp. BM var kennd eftir fyrstu 6 mánuðina. Síðan var hópnum fylgt eftir og mældur að nýju 6 mánuðum síðar. Hvíldaröndun (öndunartíðni og andrýmd (V T)), næmni öndunarstöðva metin út frá viljastýrðu öndunarstoppi, efnaskipti, og astma control spurningalisti (ACT) voru skoðuð. Hlutfall milli heildaröndunar (V´ E) og koltvísýringsútskilnaðar (V´ E/V´CO 2) var reiknað út. Fráblástursgeta á einni sekúndu (FEV 1) var mæld og reiknuð sem hlutfall af hámarksandrýmd (FEV 1/FVC). Niðurstöður : 22 (61%) af þeim 36 astmasjúklingum sem hófu rannsóknina og 20 þátttakendur í samanburðarhópi luku þátttöku. Í byrjum rannsóknarinnar voru hóparnir eins varðandi aldur, kyn og BMI, en FEV 1/FVC hlutfallið var lægra og viljastýrða öndunarstoppið styttra hjá astmahópnum (p<0.05). Eftir BM hjá astmahópnum hafði hlutþrýstingur koltvísýrings við lok útöndunar (P ET CO 2), V´ E/V´CO 2, og stig fyrir ACT aukist (p<0.05) og viljastýrða öndunarstoppið hafði lengst (p<0.001). Eins hafði hlutþrýstingur súrefnis við lok útöndunar (P ET O2), V´ E, VT og efnaskipti minnkað en BMI hafði hækkað (p<0.05). FEV 1/FVC var óbreytt. Umræða : Í upphafi var hvíldaröndun svipuð hjá hópunum en næmni öndunarstöðva var meiri hjá astmahópnum. BM virðist minnka næmni öndunarstöðva þar sem viljastýrða öndunarstoppið verður lengra. Hærra P ET CO 2 og lægra P ET O2 bendir til að hlutfall milli alveolar öndunar (V´ A) og V´CO 2 (V´ A/ V´CO 2) hafi minnkað, þrátt fyrir hærra V´ E/V´CO 2. Því má álykta að lægra V T hafi aukið öndun í dauðarýminu. BM bætir stjórnun á astma án þess að hafa breytt FEV 1/FVC. 3 4 Abstract Background : The Buteyko method (BM) seems to change breathing patterns, increase quality of life and asthma control in asthmatics. Until now, studies have not been able to identify sufficiently the physiological mechanism behind the BM. The aim of this study is to evaluate the physiological effect of BM on resting ventilation and asthma control in an asthma group. Methods : In this prospective, intervention study, asthmatics were measured 3 times at complete rest, at a 6-month interval. They were matched by age, gender, and body mass index (BMI) to control subjects. The first 6-month interval was the control period. The BM was taught to the asthmatics after the control period. Asthmatics were followed up and measured again after 6 months. Resting ventilation (respiratory rate and tidal volume (VT)), respiratory chemosensitivity evaluated by breath holding time (BHT) and metabolism were assessed, and the asthma control test questionnaire (ACT) was applied. The equivalent of pulmonary ventilation (V´ E) for carbon dioxide output (V´ E/V´CO 2) was calculated. The forced expiratory volume in one second (FEV 1) was measured and calculated as a percentage of the forced vital capacity (FEV 1/FVC). Results : 22 (61%) of 36 asthmatics and 20 control subjects finished the study. At baseline, groups were comparable regarding age, gender and BMI. In the asthma group, FEV 1/FVC was lower and BHT was shorter (p<0.05). After BM in the asthma group, partial pressure of end-tidal carbon dioxide (P ET CO 2), V´ E/V´CO 2, BMI and scores for the ACT had increased (p<0.05) and BHT had become longer (p<0.001). Partial pressure of end-tidal oxygen (P ET O2), V´ E, VT and metabolism had decreased (p<0.05). FEV 1/FVC remained the same. Discussion : At baseline, resting ventilation was alike between the groups, but respiratory chemosensitivity was higher in the asthma group as seen in shorter BHT. BM effected resting ventilation by decreasing respiratory chemosensitivity for CO 2 as evaluated by longer BHT. It could be concluded that the equivalent of alveolar ventilation (V´ A) for V´CO 2 (V´ A/V´CO 2) had decreased, evidenced by higher levels of P ET CO 2 and lower levels of P ET O2. However, V´ E/V´CO 2 had increased, implying greater dead space ventilation as a result of decreased V T. BM improved asthma control without altering FEV 1/FVC. 5 6 Acknowledgements First of all, I would like to express my deepest gratitude to my supervisor, Marta Guðjónsdóttir for carrying out this research project with me, and for all her guidance, support, encouragement, patience, and, most of all, her excellent teaching. I am very grateful to my master’s committee, Auðna Ágústsdóttir and Björn Magnússon, for supporting me in this work and for sharing their expertise. I am grateful to Reykjalundur for giving us the opportunity to perform our research in their laboratory. Finally, I would like to thank all my family and friends for their mental support, and last, but not least, my beloved daughter Katrín Möller, for her invaluable help. This project was financially supported by the Asthma and Allergy Foundation, the Icelandic Physiotherapy Society and the Oddur Ólafsson Foundation. 7 Table of contents Ágrip ........................................................................................................................................................ 3 Abstract .................................................................................................................................................... 5 Acknowledgements.................................................................................................................................. 7 Table of contents ..................................................................................................................................... 8 List of Figures ........................................................................................................................................ 10 List of tables ........................................................................................................................................... 11 List of abbreviations ............................................................................................................................... 12 1 Introduction .................................................................................................................................... 14 1.1 What is asthma? .................................................................................................................... 14 Diagnosis ................................................................................................................... 14 Risk factors and allergies ........................................................................................... 15 1.2 Asthma control ....................................................................................................................... 15 Control-based asthma management ......................................................................... 16 Psychological factors. ................................................................................................ 17 Posture and physical condition .................................................................................. 17 1.3 Ventilation at rest ................................................................................................................... 18 The Respiratory system ............................................................................................. 18 Pulmonary ventilation ................................................................................................ 22 Alveolar ventilation ..................................................................................................... 22 Dead space ventilation .............................................................................................. 23 The bicarbonate buffer system .................................................................................. 24 Spirometry.................................................................................................................. 25 Ventilation musculature ............................................................................................