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Meal-induced oxygen desaturation and dyspnea in chronic obstructive pulmonary disease
1Pulmonary Department, Mount Sinai Hospital Center, Côte St Luc, Canada.
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.