This change in the order of examination is necessary because the auscultatory findings may be markedly altered by any manipulation of the abdominal wall. Consequently percussion and palpation, which may increase or decrease peristaltic sounds are deferred until auscultation has been completedThis change in the order of examination is necessary because the auscultatory findings may be markedly altered by any manipulation of the abdominal wall. Consequently percussion and palpation, which may increase or decrease peristaltic sounds, are deferred until auscultation has been completed