What is the next step in managing a post-operative patient with fever, chills, and reduced air entry on the right side, currently on Ceftriaxone (Ceftriaxone) and Metronidazole (Metronidazole), following adhesiolysis for acute intestinal obstruction?

Post-Operative Fever with Reduced Air Entry: Immediate Chest Imaging Required

This patient requires an urgent chest X-ray to evaluate for post-operative pulmonary complications, specifically pneumonia or pleural effusion, given the combination of fever with chills and reduced air entry on the right side following abdominal surgery. 1

Immediate Diagnostic Approach

Chest Radiograph is Mandatory

• For patients who develop fever during ICU or post-operative stay, performing a chest radiograph is a best-practice statement and should not be delayed. 1
• The combination of fever, chills, and reduced air entry strongly suggests a pulmonary complication rather than benign post-operative inflammatory response. 2, 3
• Post-operative day 4 or later fever is equally likely to represent infection versus other causes, making diagnostic imaging essential rather than optional. 2

Consider Advanced Imaging if Initial Workup is Non-Diagnostic

• For patients who have recently undergone abdominal surgery, CT imaging (in collaboration with the surgical service) should be performed as part of fever workup if an etiology is not readily identified by initial evaluation. 1
• If chest X-ray shows abnormalities, thoracic bedside ultrasound can more reliably identify pleural effusions and parenchymal pathology when expertise is available. 1

Differential Diagnosis Priority

Pulmonary Complications (Most Likely)

• Pneumonia: Post-operative pneumonia commonly presents with fever, chills, and reduced air entry, particularly after abdominal surgery where diaphragmatic splinting and reduced respiratory effort are common. 3
• Pleural effusion or empyema: Can develop following subdiaphragmatic infection or inflammation tracking upward from the surgical site. 1
• Pulmonary embolism: Must be considered given immobility post-surgery, though typically presents with dyspnea and pleuritic chest pain rather than reduced air entry alone. 2, 3

Subdiaphragmatic Abscess

• A right-sided subdiaphragmatic abscess can present with reduced air entry on the right lung base due to sympathetic pleural effusion or diaphragmatic elevation. 1
• In patients with fever and recent abdominal surgery, formal bedside diagnostic ultrasound or CT of the abdomen should be performed if there is suspicion of an abdominal source. 1

Antibiotic Coverage Assessment

Current Regimen Adequacy

• The current regimen of ceftriaxone and metronidazole provides appropriate coverage for post-operative intra-abdominal infections, including both aerobic gram-negative organisms and anaerobes. 1, 4
• This combination has demonstrated efficacy in treating complicated intra-abdominal infections following bowel surgery. 4, 5

Consider Broadening Coverage Based on Findings

• If pneumonia is confirmed and the patient is not improving, consider adding coverage for hospital-acquired pathogens, particularly if MRSA risk factors are present (recent hospitalization, prior MRSA colonization). 1
• For surgical site infections with systemic signs, vancomycin should be added if MRSA risk is high. 1
• The current regimen already covers anaerobes adequately with metronidazole, which is appropriate for post-GI tract surgery. 1

Management Algorithm

1. Obtain chest X-ray immediately - do not delay for this symptomatic patient with objective findings. 1

2. Perform thorough wound examination - inspect for purulent drainage, erythema, or dehiscence that might indicate surgical site infection tracking to cause systemic symptoms. 1, 2

3. If chest X-ray shows infiltrate or effusion:

   • Continue current antibiotics initially as they provide reasonable coverage. 1
   • Consider thoracic ultrasound to better characterize pleural fluid if present. 1
   • If large effusion present, diagnostic thoracentesis may be needed.

4. If chest X-ray is normal but symptoms persist:

   • Obtain CT chest and abdomen to evaluate for subdiaphragmatic abscess or other occult source. 1
   • Consider pulmonary embolism in differential and obtain CT pulmonary angiography if clinically indicated. 2

5. If no source identified after imaging:

   • Review for drug fever or other non-infectious causes. 3
   • Consider blood cultures if not already obtained. 2

Critical Pitfalls to Avoid

• Do not attribute reduced air entry to "atelectasis" without imaging confirmation - atelectasis should be a diagnosis of exclusion, and other causes must be ruled out first. 2, 3
• Do not delay chest imaging in a symptomatic patient - fever alone in the first 48-72 hours may not require extensive workup, but fever with localizing respiratory signs mandates investigation. 2
• Do not assume current antibiotics are inadequate without identifying the source - the ceftriaxone/metronidazole combination is appropriate for post-abdominal surgery infections, but may need augmentation for hospital-acquired pneumonia. 1, 4