Thoracentesis

CHAPTER 95 Thoracentesis



Terry S. Ruhl, Jennifer L. Good


Pleural effusions are common in primary care. Sampling the fluid may yield information important for treatment decisions or may help the patient feel better. Similar techniques can also be used to treat certain pneumothoraces.



Anatomy


The pleural “space” is a potential space between the visceral pleura, which is adherent to the lung, and the parietal pleura, which is adherent to the chest wall. Normally, it contains only a thin film of lubricating fluid. When this space becomes filled with air or extra fluid, it may become painful or increase the work of breathing.



Indications



• Any significant (>10 mm on lateral decubitus radiograph) pleural effusion of unknown etiology (effusions with an easily explained cause, such as congestive heart failure, may be observed for response to therapy)

• Large symptomatic effusion

• Spontaneous pneumothorax (a minimally symptomatic, spontaneous pneumothorax of less than 20% may be merely observed if the patient has no significant underlying lung disease)


Contraindications



Absolute



• Patient refuses the procedure

• When chest tube placement is planned and would be more appropriate
• Known or suspected hemothorax

• Empyema or complicated parapneumonic effusion

• Large spontaneous pneumothorax

• Spontaneous pneumothorax in a patient with underlying lung disease


Relative



• Coagulopathy or patient undergoing anticoagulant therapy (international normalized ratio >1.5, consider reversing the coagulopathy or anticoagulant before performing thoracentesis).

• Thrombocytopenia (platelet count <50,000).

• Inability to cooperate or sign informed consent.

• Very small pleural effusions (<10 mm thick on lateral decubitus chest radiograph), unless aided by real-time ultrasonography.

• Local skin compromise (e.g., cellulitis, burn, pyoderma, herpes zoster infection).

• Unstable medical condition.

• Positive-pressure ventilation (though one study has found thoracentesis to be as safe in ventilator-dependent patients as in patients not being mechanically ventilated).

• Radiographic evidence of loculated pleural effusions making localization of fluid uncertain unless aided by real-time ultrasonography.

• Patients with chronic obstructive pulmonary disease are at increased risk for complications.


Equipment and Supplies


Commercial thoracentesis trays are available. If a commercial tray is used, the manufacturer’s instructions must be reviewed because equipment varies. Alternatively, the equipment described in the following sections can be assembled.



Preparation and Anesthesia



• Povidone–iodine solution or chlorhexidine and applicators

• Fenestrated drape or sterile towels

• 10-mL Luer-Lok syringe

• 25-gauge or smaller needle

• image– to 2-inch, 22-gauge needle

• Lidocaine 1% to 2% with epinephrine


Insertion



• Sterile gloves

• 50-mL Luer-Lok syringe, three-way stopcock

• image-inch, 18-gauge needle (for air), image-inch, 15-gauge needle (for fluid), or 16-gauge catheter over needle (can decrease risk of pneumothorax, but kinks can increase the “dry tap” rate).

NOTE: Obese people may require longer needles.


• Specimen tubes: one red top, one lavender top, culture tubes (aerobic and anaerobic), 10- to 50-mL red top for cytology, possibly 1 green top, ice for pH


Optional



• Sterile plastic tubing

• Curved clamp for marking insertion depth on needle

• 500- or 1000-mL vacuum bottles

• Telemetry, oximetry, blood pressure monitoring, and supplemental oxygen


Dressing


Use sterile gauze pads and adhesive tape or adhesive bandage with antibiotic ointment.



Precautions


The use of real-time ultrasonographic guidance is helpful in situations where there is a small effusion (<10 mm free-flowing pleural fluid on lateral decubitus radiograph), there is presence of a loculated pleural effusion, the patient is receiving positive-pressure mechanical ventilation, or in other high-risk situations. “Marking” the location for later drainage is unhelpful because fluid shifts, but marking at the time of aspiration may be helpful. Use of ultrasonography may also help determine needle depth and the angle at which the needle should be directed. Removal of large amounts of fluid may increase the incidence of postprocedure complications, although many advocate “draining it dry.”



Technique



Patient Positioning and Insertion Site



1 Seat the patient comfortably (Fig. 95-1) with arms supported on a table. The lower back should be kept as vertical as possible so that the most dependent portion of the hemithorax is posterior, thereby keeping free-flowing fluid in a posterior location.
image

Figure 95-1 Position for fluid removal.


NOTE: Debilitated patients can be placed in the lateral decubitus position, lying on the side of the effusion with their back near the edge of the bed. The procedure would then be performed in the mid-scapular line or the posterior axillary line.


2 Confirm the location and extent of fluid or air by percussion, auscultation, and study of posteroanterior, lateral, and lateral decubitus (fluid-affected side down) chest radiographs.

NOTE: If available, ultrasonography may be very helpful for completing this step (see Chapter 225, Emergency Department, Hospitalist, and Office Ultrasonography [Clinical Ultrasonography]).


3 Select the needle insertion site. Use an area one or two interspaces below the fluid level and 5 to 10 cm lateral to the spine. Do not insert below the eighth intercostal space.

4 Mark insertion site with marker or by applying pressure from the hub of a needle or pen.

5 Verify the patient’s identity, ensure the insertion site is correctly marked, and take a “time out” to verify this with everyone present.


Preparation and Anesthesia



1 Prepare the skin with povidone–iodine or chlorhexidine. Use sterile technique and universal blood and body fluid precautions. Drape with sterile towels or fenestrated drape. Some experts monitor all patients with telemetry, oximetry, and automatic blood pressure equipment and have supplemental oxygen available during this procedure, especially if the patient has underlying pulmonary disease.

2 Raise a skin wheal using lidocaine with epinephrine and a 25-gauge or smaller needle attached to a 10-mL syringe.

3 Angle a image-inch 22-gauge needle slightly downward, and insert it through the skin wheal so that the needle tip touches the superior border of a rib, aspirating and injecting as you advance. “Walk” the needle over the superior margin of the rib and deeper into the interspace, anesthetizing the intercostal muscle layers (Fig. 95-2A).

4 To confirm the presence of fluid or air with the small anesthesia needle, continue advancing the needle while aspirating and injecting until the parietal pleura has been penetrated. (A “pop” may be felt, or fluid/air aspirated.) Warn the patient that there may be a twinge of pain as you go through the pleura. Inject more lidocaine. Note the depth. Consider placing a clamp on the needle at the skin level to mark the depth (Fig. 95-2B). Withdraw the needle. If no fluid is obtained, ultrasonographic guidance is recommended. If air is unexpectedly obtained, try a lower intercostal space.

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May 14, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Thoracentesis

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