What are the potential complications and necessary precautions for a computed tomography (CT) scan guided biopsy in an adult patient with a suspected malignancy and potential underlying medical conditions, such as bleeding disorders or impaired renal function?

Complications of CT-Guided Biopsy

CT-guided biopsy carries a pneumothorax risk of 20.5% overall (with 3.1-6% requiring chest tube placement), hemorrhage risk of 5-16.9%, and mortality risk of 0.15%, with specific precautions required for patients with bleeding disorders, renal impairment, or recent cardiac events. 1

Major Complications

Pneumothorax

• Pneumothorax is the most common complication, occurring in 20.5% of all CT-guided lung biopsies, with 3.1-6% requiring chest tube drainage 1
• Hilar and perihilar biopsies carry higher risk (20-25%) due to greater distance of aerated lung tissue that must be traversed 1
• Risk factors include lesions not abutting the pleura, emphysema along the biopsy path, and nodule distance >4 cm from pleural surface 1
• Core needle biopsies have higher pneumothorax rates (25.3%) compared to fine needle aspiration (18.8%) 1

Hemorrhage

• Intrapulmonary hemorrhage occurs in 5-16.9% of patients, with hemoptysis in 1.25-5% 2, 1
• Lesion depth is the most important risk factor, with increased bleeding risk in lesions deeper than 2 cm 1
• Hemothorax occurs in approximately 1.5% of cases 1
• Deaths from bleeding are rare but reported, with fewer than 10 cases described in the literature 2

Mortality

• The overall mortality rate is 0.15% (approximately 1 in 667 procedures) 1

Rare but Serious Complications

• Air embolism can occur, particularly if biopsy is performed with patient in seated position 2, 3
• Cardiac tamponade has been reported in case reports, especially relevant for hilar lesions near mediastinal structures 1
• Tumor seeding along the needle tract has been documented 1
• Conversion of pneumonia to empyema if chest infection is present 1

Pre-Procedure Evaluation and Contraindications

Required Laboratory Testing

• PT, APTT, and platelet count must be checked before all biopsies in patients with risk factors for bleeding 2
• PT or INR or APTT ratio >1.4 and platelet count <100,000/ml are relative contraindications 2, 1
• Hemoglobin <10 g/dl warrants careful consideration before proceeding 2

Specific Patient Populations Requiring Precautions

Bleeding Disorders:

• Patients with uraemia should be given DDAVP (desmopressin acetate) before the procedure 2
• Oral anticoagulants must be stopped according to perioperative anticoagulation guidelines 1
• Patients with pulmonary arterial or venous hypertension may have increased hemorrhage risk, though no definitive data exists 2

Renal Impairment:

• Chronic renal insufficiency increases bleeding risk and impairs drug handling 1
• These patients benefit from DDAVP administration prior to the procedure 2

Cardiac Disease:

• The procedure should not be performed within 6 weeks of myocardial infarction 1
• Severe cardiac disease increases arrhythmia risk during procedures 4

Hepatic Disease:

• Chronic hepatic insufficiency increases bleeding risk and impairs drug handling 1
• Liver disease is associated with coagulation disorders that increase hemorrhage risk 2

Absolute and Relative Contraindications

• Uncooperative patients represent a contraindication, as sudden movement while the needle is in lung parenchyma may cause tearing and subsequent bleeding or pneumothorax 2, 1
• Patients planning to fly within 6 weeks should not undergo biopsy 1
• Mechanical ventilation makes the procedure more difficult but is not an absolute contraindication if lesion is accessible by ultrasound 2
• Vascular lesions (aneurysms or arteriovenous malformations) should not be biopsied 2

Critical Procedural Precautions

Patient Positioning

• Biopsy specimens should not be taken with patient in seated position due to risk of air embolus or fainting 2
• Position patient prone or supine depending on skin entry site 2
• Avoid decubitus position if possible as it is difficult for patients to maintain consistently 2

Patient Instruction

• Deep breaths and coughing should be avoided during the biopsy procedure 2
• Breathing technique must be explained and practiced beforehand 2
• Anxiolytic drugs may be helpful for frightened patients after careful explanation and reassurance 2

Imaging Review

• Recent chest radiographs and CT scans must be reviewed to decide if biopsy is appropriate 2
• If significant delay has occurred between staging CT and biopsy, repeat imaging should be performed to assess for tumor growth or stage change 2
• CT should preferably be performed before bronchoscopy 2

Post-Procedure Monitoring

Immediate Monitoring

• Close observation for pneumothorax and hemorrhage is essential in the first 2-4 hours 5
• Monitor for severe or increasing pain disproportionate to expected discomfort 5
• Watch for tachycardia and hypotension as critical indicators of blood loss 5

Delayed Complications

• Severe bleeding can occur up to one week after the procedure, possibly related to premature clot dissolution 5
• Patients must be educated about warning signs requiring immediate medical attention before discharge 5

Risk Mitigation Strategies

Imaging Modality Selection

• Ultrasound guidance should be used whenever possible for lesions with pleural contact, as it is the safest, quickest, and least expensive method 2, 6
• Ultrasound-guided biopsy is associated with fewer complications (7%) compared to CT-guided procedures (24%) 6
• For lesions not suitable for ultrasound, CT is the preferred imaging modality 2

Technical Considerations

• Biopsy sites away from identified areas of cavitation or necrosis should be chosen 2
• Standard universal precautions with protective gloves should be used 2
• CT fluoroscopy guidance reduces complication rates (13.4%) compared to conventional CT (31.4%), though with higher radiation exposure 7