Stage 3 — Prioritize hypotheses. Mr. B, who has diabetes and obesity, is on postoperative day 5 after colorectal surgery; prophylactic antibiotics stopped after incision closure. Overnight he developed a temperature of 38.6 C with heart rate 102/min; BP is 124/76 mm Hg and lactate 1.4 mmol/L. Yesterday afternoon the incision was intact and dry; it now has purulent yellow drainage saturating the dressing, erythema extending 5 cm with increasing incisional tenderness, and two loose staples at the draining area without a gap through deeper layers. The abdomen is soft without rigidity or crepitus. He is alert, tolerating a diet, and ambulating with assistance. WBC has risen from 9.2 to 16.8 x 10^9/L with neutrophilia, and glucose is 246 mg/dL. Complete the diagram by selecting the condition the client is most likely experiencing, 2 actions the nurse should take to address that condition, and 2 parameters the nurse should monitor to assess the client's progress.

Quick answer
Condition: incisional surgical site infection. Actions: notify the surgeon for incision evaluation (opening and drainage), and collect an aseptic wound specimen during drainage. Monitor: temperature and heart rate, and the erythema edge versus the marked line.

Why this is correct
Surgical site infections typically appear 4 to 7 days after surgery. Purulent drainage from the incision is the defining sign, and spreading erythema with tenderness confirms it; fever and a WBC of 16.8 show a systemic response. Source control (opening and draining the incision) is the main treatment, and the best culture comes from deep tissue or pus collected aseptically at that time. Marking the erythema edge and trending temperature and heart rate show whether the infection is receding after drainage and antibiotics.

Easy analogy or mental picture
An infected incision is a pimple that has to be opened: antibiotics help, but relief comes when the pus drains. Drawing a line around the redness is how you see whether the fire is shrinking.

Memory hook
Pus + spreading red + POD 4 to 7 = open it, culture the pus, draw the line.

NCLEX decision rule
Identify the depth of an infection from the data (incision versus abdomen) and choose source control first; monitor the local border and systemic signs that reflect that specific infection.

Why the other choices are wrong
An anastomotic leak shares fever and leukocytosis, but the abdomen is soft without rigidity, so emergency laparotomy and checks for rigidity follow the wrong problem. Septic shock is excluded by a BP of 124/76 and lactate of 1.4; a 30 mL/kg bolus and 15-minute MAP checks are for hypoperfusion he does not have. Fascial dehiscence is tempting because staples are loose, but there is no gap through deeper layers and the drainage is purulent, not serosanguineous. A swab of an old dressing surface grows skin contaminants and misleads therapy. Serum albumin reflects nutrition and healing, not the infection's response to treatment.