Perioperative & Surgical Critical Care

Preoperative risk and medications

Cardiac risk. Estimate risk with the Revised Cardiac Risk Index (RCRI) plus functional capacity. RCRI assigns a point each for high-risk surgery (intraperitoneal, intrathoracic, or suprainguinal vascular), ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, and creatinine >2 mg/dL.

Who needs more workup. A patient who manages 4 METs is low risk and goes to surgery. Poor or unknown capacity in an elevated-risk patient justifies stress testing only if the result would change management. Active cardiac conditions (unstable angina, decompensated heart failure, significant arrhythmia, severe valvular disease) are evaluated and stabilized before elective surgery; true emergencies proceed.

Preventing VTE and surgical site infection

VTE prophylaxis. Risk-stratify with the Caprini score. Lower-risk patients need early ambulation and mechanical prophylaxis (sequential compression devices); moderate-to-high risk patients get pharmacologic prophylaxis with low-molecular-weight or unfractionated heparin, with mechanical devices alone while bleeding risk is prohibitive. Major orthopedic surgery (hip or knee) and cancer carry the highest risk and often warrant extended prophylaxis. IVC filters are not a prophylactic tool.

SSI prevention bundle.

• Prophylactic cefazolin within 60 minutes before incision so tissue levels peak at contamination; add anaerobic coverage (e.g., metronidazole) for colorectal cases.
• Redose during long operations or with major blood loss; stop within 24 hours after surgery.
• Remove hair with clippers, not razors: shaving causes microabrasions that raise infection risk.
• Chlorhexidine skin preparation.
• Maintain normothermia.
• Keep glucose below roughly 180–200 mg/dL.

Postoperative fever: the five W's

Timing is the diagnosis. The postoperative day narrows the cause, then the exam confirms it.

Early fever is usually the inflammatory response to surgery. Fever in the first 48 hours usually reflects tissue injury and cytokine release, not infection. Atelectasis is common after abdominal or thoracic surgery but is not a proven cause of fever; prevent it with incentive spirometry, early ambulation, and adequate pain control so the patient can breathe deeply. The important early infectious causes are pneumonia, aspiration, and necrotizing wound infection (group A Streptococcus or Clostridium).

Fever within hours of anesthesia with rising end-tidal CO₂, muscle rigidity, and hyperkalemia is malignant hyperthermia (RYR1; triggered by volatile anesthetics or succinylcholine): stop the trigger and give dantrolene. A very early wound fever with severe pain and gray drainage suggests necrotizing infection from group A streptococcus or Clostridium, which needs emergent debridement.

Postoperative complications

Ileus. A functional (non-mechanical) stall causing distension, absent bowel sounds, and no flatus, expected for up to 3–5 days after abdominal surgery. The small bowel recovers first, the stomach next, and the colon last. Minimize opioids (alvimopan, a peripheral μ-opioid antagonist, can speed recovery), encourage ambulation, correct potassium and magnesium, and decompress with a nasogastric tube if vomiting. Ileus that outlasts its expected course should prompt a search for a leak, abscess, or mechanical obstruction.

Anastomotic leak. Around postoperative days 5–7 after bowel surgery, fever, tachycardia, worsening abdominal pain, peritonitis, and leukocytosis mean a leak until proven otherwise; it can progress to sepsis. Diagnose with contrast-enhanced CT. Treat with resuscitation and antibiotics plus drainage (percutaneous for a contained collection) or reoperation for diffuse peritonitis.

Wound dehiscence. Fascial separation is often heralded by a sudden gush of salmon-colored (pink, serosanguinous) fluid from the incision around days 5–8. Risks are infection, obesity, poor nutrition, and raised intra-abdominal pressure, plus steroids and diabetes.

Evisceration (bowel through the wound) is an emergency: cover the bowel with saline-soaked gauze and take the patient to the operating room.

Venous thromboembolism. Postoperative DVT (the Walking W, days 4–6) causes unilateral leg swelling and pain; pulmonary embolism causes sudden dyspnea, pleuritic chest pain, tachycardia, and hypoxia. Prophylaxis is the priority. Diagnose DVT with compression ultrasound and PE with CT pulmonary angiography.

Perioperative MI. Most occur on postoperative days 1–3 and are often silent or atypical because analgesia masks chest pain; it is a leading cause of postoperative death in cardiac-risk patients. Check troponin and an ECG when unexplained hypotension, dyspnea, or arrhythmia appears.

Surgical nutrition and refeeding syndrome

If the gut works, use it. Enteral nutrition is preferred over parenteral whenever the gut is functional: it preserves mucosal integrity, limits bacterial translocation, and reduces infections. Total parenteral nutrition is reserved for a nonfunctional gut and risks central line infection, hyperglycemia, cholestasis, and refeeding syndrome.

Refeeding syndrome. When a malnourished patient is fed, the insulin surge drives phosphate, potassium, and magnesium into cells. Falling phosphate defines the syndrome and can cause weakness, respiratory failure, arrhythmias, and heart failure.