What are the key complications to watch out for after a medical procedure?

Post-Procedure Complications Monitoring

Monitor all patients for signs of infection, bleeding, cardiovascular events, and organ dysfunction, with the highest risk period being days 1-3 postoperatively, though serious complications can occur up to 28 days after surgery.

Immediate Post-Procedure Period (0-48 Hours)

Critical Complications Requiring Urgent Recognition

Cardiovascular Events

• Watch for chest pain, shortness of breath, weakness, or slurred speech indicating thrombotic events, which can occur as early as the first weeks after procedures 1
• Monitor blood pressure closely, as new-onset hypertension or worsening of pre-existing hypertension can develop 1
• Assess for signs of heart failure: unexplained weight gain, peripheral edema, or dyspnea 2

Hemorrhagic Complications

• Examine access sites for bleeding, hematoma, pseudoaneurysm formation, or retroperitoneal hemorrhage (presenting as hypotension, suprainguinal tenderness, severe back or lower-quadrant abdominal pain) 1
• Monitor hematocrit for decreases >5-6% absolute 1
• For procedures involving anticoagulation or antiplatelet therapy, bleeding risk is substantially elevated 1

Respiratory Complications

• Assess for airway obstruction, particularly in patients who received muscle relaxants or sedation, as residual neuromuscular blockade can affect tongue and pharyngeal muscles 1
• Monitor for pulmonary embolism, pneumonia, or aspiration (not atelectasis, which is typically benign) 3

Access Site Complications

• Inspect for vessel injury, nerve damage in surrounding soft tissue, arteriovenous fistula (continuous murmur over puncture site), or localized infection 1
• Radial artery occlusion occurs in 1-10% of transradial procedures but is often asymptomatic due to collateral circulation 1

Days 3-7 Post-Procedure

Peak Risk Period for Complications

The highest incidence of morbidity occurs on postoperative day 3, with 60% of patients experiencing at least one complication in this timeframe 1. This is when most infectious and physiologic complications manifest.

Infection Surveillance

• Monitor for fever, wound erythema, purulent drainage, or systemic signs of infection 1, 4
• For surgical site infections: nearly half (48%) are diagnosed after hospital discharge, requiring post-discharge follow-up 5
• Deep infections require urgent surgical debridement, hardware removal if implants are involved, and culture-directed antibiotics 4

Gastrointestinal Complications

• Watch for anastomotic leaks (localized fluid/gas around anastomosis on imaging, though may overlap with normal post-operative appearance) 1
• Monitor for bowel obstruction, abscess formation, or toxic megacolon (colonic dilatation >6 cm, mural thinning <2 mm) 1
• NSAIDs can cause serious GI bleeding, ulceration, and perforation—often without warning symptoms 2

Renal and Metabolic Complications

• Acute kidney injury is common and highly predictive of mortality 1
• Monitor for rhabdomyolysis (reddish urine, elevated creatine kinase) requiring forced diuresis and urine alkalinization 1

Days 7-21 and Beyond

Late Complications

Thromboembolic Events

• 27.3% of thromboembolic events occur after leaving the procedure room, with mean occurrence at 4.4±5.6 days 1
• Mesenteric venous thromboembolism risk is elevated, particularly in inflammatory conditions 1

Delayed Infections

• If signs/symptoms persist beyond 3 weeks, obtain CT scan or endoscopy to evaluate for contained infections 1
• Pharmacologic treatment: amoxicillin/clavulanic acid 1g TID + metronidazole 500mg TID, or levofloxacin 400mg BID for 7-10 days 1
• If symptoms persist despite antibiotics, surgical removal of infected material is mandatory 1

Delayed Neuromuscular Complications

• Muscle weakness can occur up to 4 days after exposure to certain agents, requiring prolonged ventilatory support 1

Procedure-Specific Complications

Endovascular/Catheter-Based Procedures

• Device-related: vasospasm, arterial perforation/dissection, device detachment with complication rates of 4-29% 1
• Contrast-induced nephropathy requires monitoring and prevention protocols 1
• Orolingual angioedema occurs in 1.3-5.1% post-thrombolysis, often contralateral to affected hemisphere 1

Sinus/Maxillofacial Procedures

• Schneiderian membrane perforation (occurs in 20% of lateral window approaches) can lead to graft displacement and sinusitis 1
• Subacute sinusitis manifests 3-7 days post-op with severe suborbital pain, requiring immediate drainage, debridement, and high-dose antibiotics 1
• Abnormal postoperative bleeding (14.5%) typically from posterior superior alveolar artery damage 1

Orthopedic Procedures

• Complete fracture during correction, compromised implant position, or lack of primary stability leading to nonunion/malunion 6
• Diabetic patients require more vigilant monitoring due to increased infection risk and impaired wound healing 4

Monitoring Strategy

Track and Trigger Systems

Implement early warning scores (EWS, MEWS, NEWS) to detect complications up to 3 days before clinical diagnosis 1. These systems predict major adverse events with high accuracy when tied to specific interventions like rapid response team activation.

High-Risk Patients Requiring ICU/Enhanced Monitoring

• Patients with predicted mortality ≥10%, complex procedures, or serious comorbidities 1
• Cardiovascular and renal complications on any postoperative day are highly predictive of mortality 1

Medication-Related Complications

NSAID Use Post-Procedure

• Increased risk of MI, stroke, heart failure, and GI bleeding/perforation 2
• Avoid in patients with recent MI, post-CABG, or severe heart failure 2
• Use lowest effective dose for shortest duration; monitor BP throughout treatment 2
• Can impair response to diuretics, ACE inhibitors, and ARBs 2

Common Pitfalls

• Early fever (<48 hours) is usually benign and self-limiting; extensive workups with cultures and imaging have minimal yield in elective surgery patients 7
• Physical examination has the highest diagnostic yield for determining fever etiology—blood cultures in elective surgery patients with early fever have zero positive results 7
• Do not dismiss fever after 48 hours—this is when infectious causes become more likely 3, 8
• Failure to rescue (mortality after complications) is determined by effective response to complications, not their incidence 1