thoracentesis (pleuracentesis, pleurocentesis, pleural tap, transthoracic needle aspiration ,thoracocentesis)

Introduction

transthoracic needle aspiration

Indications

• pleural effusion of undetermined origin
• therapeutic:
  • for improving pulmonary status
  • contralateral mediastinal shift
• small pneumothoraces

Contraindications

• hemorrhagic disorder*
• active local infection over the area of access

* ultrasound-guided thoracentesis can be done safely even in patients on anticoagulants or antiplatelet agents

Laboratory

• preprocedural
  • platelet count > 50,000/uL
  • international normalized ratio (INR) < 2.0
  • can be performed safely under ultrasound guidance with INR < 3.5 & platelet count > 20,000/uL
• pleural fluid analysis: (see pleural effusion)
• Useful studies in pleural fluid analysis include:
  • Gram's stain, cell count & differential, amylase, triglycerides, microbiologic stains, cultures, cytology, LDH, glucose, protein
• priming the fluid collection bag with 300-1000 U of heparin & submitting a large volume of pleural fluid may increase diagnostic yield;
  • for direct smear/cytospin & cell block preparations, >= 150 mL is recommended
  • for direct smear/cytospin only, 60 mL is adequate

Procedure

preparation: see Radiology:

precautions:

• always approach from the top of the rib
  • vessels and nerves run along inferior aspect of ribs
• a clamp placed on the needle may prevent overpenetration
• be prepared for pneumothorax
• bedside ultrasound recommended

procedure

• position patient on the edge of bed with arms supported by a table
• percuss the effusion to the highest & lowest levels
• determine point of access
• choose an access above the 8th rib, as low in the effusion as possible
• mark the spot to indent the skin
• prepare the skin with disinfectant
• anesthetize with lidocaine 1%, locally
  • make a wheal using a 25 gauge needle
  • anesthetize the periosteum of the rib, walking the needle superiorly
  • advance the needle into the pleural cavity & aspirate to confirm fluid or air & note depth of needle
• place clamp on intracath needle at the depth noted in 7c
• enter pleural cavity with intracath at top of rib & confirm fluid or air
• advance catheter through needle
• aspirate fluid, not more than 1.5 liters
• remove the catheter as a unit
• do not pull the catheter back through the needle
• cover insertion with bandage

* video with ultrasound guidance

Radiology

• obtain PA, lateral & decubitus radiographs
  • thoracentesis can be safely performed on effusions demonstrating a thickness of 1 cm on lateral decubitus radiograph in the absence of hemostasis disorders.
• loculated effusions may be localized with ultrasound or CT
  • US reduces the risk of pneumothorax

Complications

• pneumothorax
• hemothorax
• re-expansion pulmonary edema
• intrapulmonary hemorrhage
• hemoptysis
• vagal inhibition
• air embolism
• subcutaneous emphysema
• bronchopleural fistula
• empyema
• puncture of liver or spleen

Management

Follow-up:

• chest X-ray
• pain relief as needed
• oxygen for post-thoracentesis hypoxia
  • secondary to ventilation perfusion mismatch after lung expansion

More general terms

• clinical procedure

Additional terms

• pleural effusion