Have client place meter mouthpiece in the mouth and close lips, making a firm seal.
Have client place meter mouthpiece in the mouth and close lips, making a firm seal.
让病人将计量器放入口中，紧闭嘴唇，使不漏气。
Have client place meter mouthpiece in the mouth and close lips, making a firm seal.
让病人将计量器放入口中，紧闭嘴唇，使不漏气。