The volume-time trace should have a rapid smooth initial rise in volume, with flattening of the trace to a plateau within 3-5 s. Greater than 70% of the total expired volume should be exhaled in the first second. The flow-volume trace also has a steep smooth initial phase leading to the maximal expiratory flow level and then flow rate decreases in a fairly linear way until the residual volume is reached. Following three satisfactory blows, values for FEV1, FVC and the FEV1/FVC ratio can be obtained and compared with predicted values for the individual.

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Sleep Apnea

Sleep Apnea

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