Post-operative Complications: Recognition, Prevention, and Nursing Priorities

Post-operative complications occur after surgery as a result of anesthesia effects, immobility, infection risk, and physiological stress. Early recognition is essential because many of these complications can rapidly become life-threatening if not treated promptly. This guide summarizes the most common complications by system, their typical timing, presenting signs, and the priority nursing actions.

Quick reference: common complications

• Atelectasis (24–48 h): low-grade fever, crackles, tachypnea → incentive spirometry, deep breathing, coughing, early ambulation.
• Pneumonia (2–5 days): high fever (>38.5°C), productive cough, purulent sputum, crackles → antibiotics, sputum culture, respiratory support.
• Pulmonary embolism (PE) (5–14 days): sudden dyspnea, pleuritic chest pain, hypoxemia, tachycardia → oxygen first, notify provider, prepare for CT angiography.
• Deep vein thrombosis (DVT) (2–7 days): unilateral calf swelling, pain, warmth, erythema → do NOT massage; notify provider; Doppler ultrasound.
• Urinary retention (24–48 h): bladder distension, inability to void, suprapubic pain → bladder scan; straight catheterize if >600 mL.
• Ileus (24–72 h): absent bowel sounds, distension, nausea, vomiting → NPO, NG tube if vomiting, ambulation.
• Wound infection (3–7 days): erythema, warmth, purulent drainage, fever → wound culture, antibiotics, sterile dressing change.
• Wound dehiscence (5–10 days): sudden serosanguineous drainage, edges separate → cover with sterile saline gauze; notify surgeon.
• Wound evisceration (5–10 days): organs protrude through wound → saline gauze, knees bent, emergency surgery; do NOT reinsert.
• Hemorrhage (first 24 h): hypotension, tachycardia, decreased urine output, bright red blood → IV fluids, notify provider, prepare for transfusion.

Respiratory complications

Atelectasis

• The most common post-operative complication, occurring within 24–48 hours.
• Caused by alveolar collapse from shallow breathing or retained secretions.
• Signs: low-grade fever, decreased breath sounds, crackles, increased respiratory rate.
• Priority interventions: incentive spirometry, deep breathing, coughing, early ambulation, and adequate pain control.

Pneumonia

• Lung infection developing about 2–5 days post-op.
• Signs: high fever, productive cough with purulent sputum, crackles, elevated WBC.
• Management: antibiotics, sputum culture, oxygen therapy, respiratory support.

Pulmonary embolism (PE)

• Life-threatening clot lodged in the pulmonary circulation.
• Signs: sudden shortness of breath, pleuritic chest pain, tachycardia, low SpO₂, anxiety.
• First action: administer oxygen, then notify the provider and prepare for diagnostic imaging (CT angiography).

Thromboembolic complications

Deep vein thrombosis (DVT)

• Blood clot in a deep vein, usually in the leg.
• Signs: unilateral swelling, warmth, redness, and pain.
• Never massage the leg — this may dislodge the clot and cause a PE.
• Prevention: early ambulation, sequential compression devices, anticoagulants, leg exercises.

Urinary complications

Urinary retention

• Inability to empty the bladder after surgery; common after anesthesia, opioids, or pelvic surgery.
• Signs: bladder distension, suprapubic pain, inability to void.
• First action: bladder scan; catheterize if necessary (straight cath if >600 mL).

Urinary tract infection (UTI)

• Often related to indwelling catheters.
• Signs: burning with urination, urgency, foul-smelling urine, suprapubic discomfort.
• Prevention: early catheter removal, sterile technique.
• Obtain a urine culture before starting antibiotics.

Gastrointestinal complications

Ileus

• Temporary loss of bowel motility after surgery.
• Signs: absent bowel sounds, abdominal distension, nausea, vomiting.
• Management: NPO status, NG tube if vomiting, early ambulation.

Post-operative nausea and vomiting (PONV)

• Common after anesthesia and opioid use.
• Risk factors: female sex, non-smoking status, history of motion sickness.
• Treatment: antiemetics and side-lying position to prevent aspiration.

Wound complications

Wound infection

• Develops several days after surgery.
• Signs: redness, warmth, swelling, purulent drainage, fever, increased pain.
• Obtain a wound culture before antibiotics; provide sterile wound care.

Wound dehiscence

• Separation of surgical wound edges, often preceded by sudden serosanguineous drainage.
• Action: cover with sterile saline-soaked gauze and notify the surgeon immediately.

Wound evisceration

• Surgical emergency — abdominal organs protrude through the incision.
• Action: cover organs with sterile saline-soaked gauze, position patient supine with knees bent, notify surgeon, prepare for emergency surgery.
• Never attempt to reinsert the organs.

Cardiovascular complications

Hemorrhage

• Excessive post-operative bleeding, usually in the first 24 hours.
• Signs: hypotension, tachycardia, decreased urine output, bright red drainage.
• Management: IV fluids, prepare for blood transfusion, notify provider immediately.

Hypotension

• May result from bleeding, infection, or anesthesia effects.
• Action: assess ABCs, administer fluids, escalate care as needed.

Post-operative fever — the Five W's

Timing guides the likely cause:

• Fever within 24 hours is usually atelectasis or inflammation.

• Fever after 48 hours is more likely infection.

• Wind — lung problems (atelectasis, pneumonia)

• Water — urinary tract infection

• Wound — surgical site infection

• Walking — blood clots (DVT, PE)

• Wonder drugs — medication reactions

Nursing priorities

• Maintain airway and breathing.
• Encourage early ambulation.
• Prevent blood clots (SCDs, anticoagulants).
• Monitor wounds for infection, dehiscence, or evisceration.
• Manage pain effectively.
• Ensure adequate hydration and elimination.

Common exam traps

• Atelectasis is the most common cause of early post-op fever — it is not infection.
• A suspected DVT must never be massaged.
• Wound evisceration: cover organs with sterile saline-soaked gauze — never reinsert.
• Urinary retention is common after anesthesia and requires bladder scanning.
• Incentive spirometry is the most important intervention for preventing atelectasis.

Key takeaways

• Atelectasis is the most common early post-op complication; prevent with incentive spirometry, deep breathing, and early ambulation.
• DVT presents with unilateral leg swelling — never massage; prevent with anticoagulants and SCDs.
• PE is a medical emergency: oxygen first, then notify provider.
• Wound dehiscence and evisceration are both covered with sterile saline-soaked gauze; evisceration is a surgical emergency and organs are never reinserted.
• Use the Five W's (Wind, Water, Wound, Walking, Wonder drugs) to identify the cause of post-op fever based on timing.
• Hemorrhage in the first 24 hours requires immediate fluid resuscitation and provider notification.