Final answer:
The most indicative sign of a small bowel obstruction is visible peristaltic waves in the upper abdomen, which suggest the body is attempting to move the contents through the obstructed area.
Step-by-step explanation:
The patient reports severe constipation. The nurse should identify which of the following findings is an indication that the client might have a small bowel obstruction? Among the listed options, the most indicative sign of small bowel obstruction is the presence of visible peristaltic waves in the upper abdomen. This occurs as the body attempts to move the contents through the obstructed area, causing the waves to be visible as they pass over the area of obstruction. This finding, coupled with intermittent cramping in the lower abdomen, support the suspicion of a small bowel obstruction, distinct from the general symptoms such as peripheral edema or minimal vomiting.