Thoracentesis is a procedure that uses ultrasound to locate a pocket of free fluid within the chest cavity. This assists the pulmonologist in placing a temporary catheter to drain the fluid.


  • You will sit upright on an exam table with your back exposed.
  • A non-greasy gel will be applied to your skin during the exam.
  • The sonographer will use a hand-held transducer (probe) against your back to obtain images of the fluid in your chest.
  • The sonographer then shows the pulmonologist the largest pocket of fluid.
  • The pulmonologist numbs the area with Lidocaine to aid in any discomfort the procedure causes.
  • The pulmonologist then sterilizes the area and places a temporary catheter within the chest.


  • You must have labs drawn prior to having this procedure done: PT, PTT, INR.
  • The pulmonologist sometimes has the labs already drawn before scheduling this procedure.
  • You may eat or drink before this exam.
  • Arrive 15 minutes prior to your scheduled appointment.
  • Bring a prescription from your doctor.


Let the technologist know:

  • If you take any medications.
  • If you have an allergy to Lidocaine.
  • If you have difficulty sitting upright.
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