Meal Induced Oxygen Desaturation and Dyspnea in Chronic Obstructive Pulmonary Disease

Abstract

OBJECTIVE: To study arterial oxygen saturation (SpO₂) obtained by pulse oximetry and dyspnea during active eating (AE) and passive eating (PE) in patients with severe chronic obstructive pulmonary disease (COPD).DESIGN: Patients were studied on two consecutive days with AE and PE, which occurred in random order. SpO₂ was recorded for 20 mins before and during eating, and dyspnea was recorded by the patient using a 10 cm visual analogue scale before and upon completion of eating.SETTING: Subjects were in-patients at an intermediate care facility who were hospitalized for pulmonary rehabilitation or for convalescence after an exacerbation of COPD.POPULATION STUDIED: Thirty-five patients with severe COPD (forced expiratory volume in 1 s [FEV₁] less than 50% predicted, FEV₁ to forced vital capacity ratio less than 65%) were studied. Mean age was 70.5±7.1 years.MAIN RESULTS: Mean SpO₂ decreased significantly (P<0.05) from 91.7±3.4% to 90.1±4.0% during AE, and 91.7±3.2% to 90.8±3.6% during PE. Mean lowest SpO₂ was lower and percentage of time with SpO₂ less than 90% was greater during eating compared with corresponding control periods during both AE and PE. Dyspnea increased significantly (P<0.05) from 1.4±1.2 to 3.3±2.3 cm during AE, and from 1.5±1.5 to 2.4±2.2 cm during PE. The increase in dyspnea was significantly greater during AE than PE.CONCLUSIONS: Eating is an activity that can adversely affect SpO₂ and increase dyspnea in patients with severe COPD. Oxygen desaturation and particularly increased dyspnea may at least in part relate to the recruitment of upper extremity muscles during eating.