Thoracentesis

Chapter 31 Thoracentesis



Nadja E. Sigrist, Dr.Med.Vet., FVH, DACVECC



KEY POINTS



• Thoracentesis is an easily performed diagnostic and therapeutic procedure and is safe if performed by skilled personnel.

• Blind thoracentesis is performed between the seventh and ninth intercostal spaces.

• Thoracentesis for fluid removal is best guided by ultrasonography.

• Strict aseptic technique is required.

• Indications for thoracentesis are pneumothorax and pleural effusions (chyle, transudate, blood).

• Contraindications to thoracentesis include severe coagulopathies, thrombocytopenia, and thrombocytopathia.


INTRODUCTION


The removal of fluid or air by puncturing the chest with a hollow needle, catheter, or tube is called thoracentesis, and it can be used as both a diagnostic tool and a therapeutic intervention.1 In contrast to the emergency patient, pleural effusions are more common than pneumothorax in the critically ill patient.1,2 In this patient population, pleural effusion may be caused by the primary disease process or can have secondary cardiovascular or iatrogenic causes. In humans, pleural effusions commonly accompany edematous states due to heart failure or volume overload, pneumonia, or acute respiratory distress syndrome.2 Thoracentesis is an easy and potentially lifesaving procedure that every emergency and critical care veterinarian should be able to perform. Several techniques are discussed in this chapter.3,4



INDICATIONS


Animals with pleural space disease experience respiratory distress and may show an inward abdominal movement during inspiration. Other animals (especially cats) often show superficial and fast breathing. On auscultation, decreased lung sounds may be heard unilaterally or bilaterally. Lung sounds are generally decreased in the dorsal lung fields in association with pneumothorax and in the ventral regions of the chest in association with pleural effusion. Other clinical signs such as a heart murmur, distended jugular veins, increased lung sounds, coughing, bowel sounds heard during chest auscultation, or the feeling of missing organs on abdominal palpation might help in the differentiation of pleural space diseases. Thoracic radiographs, ultrasonography, echocardiography, packed cell volume and total solids, and albumin measurements may further help identify the cause of respiratory distress and the need for thoracentesis. Thoracentesis can be an important diagnostic and life- saving therapeutic intervention in the animal with severe respiratory distress and should not be withheld in the absence of a confirmed diagnosis of pleural space disease.


Indications for thoracentesis are diagnosis or suspicion of pneumothorax, tension pneumothorax, or pleural effusion.1,3 Pneumothorax can be traumatic or spontaneous in nature. Pleural effusion can arise from heart failure, inflammation associated with pneumonia, pancreatitis, pyothorax or feline infectious peritonitis, chylothorax, neoplasia, bleeding disorders, trauma, or lung lobe torsion.2,5 Thoracentesis is indicated when air or fluid accumulation in the pleural space is believed to be causing or contributing to respiratory difficulties. Diagnostic thoracentesis in critically ill patients is indicated for pleural effusions that cannot be otherwise explained. Treatment of suspected infectious processes such as feline infectious peritonitis and pyothorax will usually include pleural drainage.2,3


Relative contraindications are pleural space diseases that cannot be treated by thoracentesis. These include pneumomediastinum, diaphragmatic hernia without fluid accumulation, and pleural masses. Other possible contraindications are bleeding disorders and large bullae because they may lead to deterioration of the patient’s respiratory status.1



MATERIALS


If not already initiated, supplemental oxygen should be administered to all patients before any handling or restraint.3 Material for orotracheal intubation, including a functional strong light source, should be prepared and ready to use when handling dyspneic patients. The required materials for the procedure should be prepared before handling the patient. Equipment needed for thoracentesis is summarized in Box 31-1.



Box 31-1 Equipment Needed for Thoracentesis



• Clippers

• Surgical prep solution

• Lidocaine (1% to 2%)

• Gloves (sterile)

• Butterfly needle or over-the-needle catheter or hypodermic needle of appropriate size

• Extension set

• Three-way stopcock

• 10- to 60-cc syringe, depending on patient size and expected amount of fluid or air

• Tubes for fluid analysis (ethylenediaminetetraacetic acid, heparin, sterile tube for bacterial culture)

• Sterile saline (if using the needle technique)

Thoracentesis is performed with a needle, peripheral catheter, or flexible tube placed within the pleural space.1 It is generally recommended to use the smallest gauge catheter or needle possible.1 For example, to aspirate air, a 22-gauge butterfly needle can be used in cats and small dogs, and an 18-gauge butterfly needle may be effective in medium and large dogs. The catheter size is generally increased for the aspiration of pleural effusions.


Thoracentesis requires a minimum of two, and ideally three, people. One person is needed to restrain and limit patient movement, one to place and stabilize the needle, and one to aspirate and collect the fluid or air. The person operating the syringe and stopcock needs both hands, so if only two people are available, the person doing the tap and holding the needle in place also has to restrain the patient.

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  4. Pulmonary Contusions and Hemorrhage

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Sep 10, 2016 | Posted by in SMALL ANIMAL | Comments Off on Thoracentesis

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