Eliminate the air of mystery from chest tubesDEBORAH LAZZARA

Nursing2002June 2002 Volume 32 Number 6 Pages 36 – 43

Eliminate the air of mystery from Chest tubes

Use this guide to understand when your patient may need a chest tube and how to manage the drainage system.

BY DEBORAH LAZZARA, RN, APRN-BC, CCRN, MS

ANXIOUS AND TACHYCARDIC, John Williams, 26, comes to the emergency department complaining of chest pain and difficulty breathing. Suffering from a bad cold, he developed the problem soon after a bout of forceful coughing.

Your quick assessment reveals decreased breath sounds on his right side, and the right side of his chest barely moves on inspiration. His Spo2 reading is 88%. Suspecting that Mr. Williams is experiencing a pneumothorax, you elevate the head of his bed to 45 degrees and administer oxygen at 2 liters/minute. You titrate the flow until his Spo2 reaches 94% and page the pulmonologist.

A pneumothorax is a medical emergency that calls for placement of a chest tube and use of a chest drainage unit (CDU). To help Mr. Williams through this crisis, you need to understand how chest tubes and CDUs work, how to assist during tube insertion and removal, and how to monitor his condition. I'll cover these topics below. But first, let's look at why he might need a chest tube in the first place.

Removing air or fluid from the pleural space

The purpose of a chest tube (also known as a thoracostomy tube or thoracic catheter) is to remove air or fluid from the pleural space. A chest tube is commonly inserted to resolve pneumothorax, hemothorax, or pleural effusion or to drain blood from the mediastinum after open-heart surgery. (See A Range of Reasons for Chest Tube Placement to learn more.)

Pneumothorax is the most common reason for inserting a chest tube. Leading to partial or complete lung collapse, it's caused by external air entering the pleural space from a hole in the chest wall or by air in the lungs entering through a hole in the pleura. The collected air disrupts the normal negative pressure within the lungs--the vacuum that keeps them expanded. Loss of this vacuum causes the lung to collapse; a collapse of greater than 15% can lead to respiratory compromise, so insertion of a chest tube is necessary.

Tension pneumothorax, a life-threatening emergency, occurs when the air accumulating in the pleural space increases pressure to a dangerous level, causing a mediastinal shift that pushes the heart, great vessels, trachea, and lungs toward the unaffected side. This shift severely decreases lung expansion, venous return, and cardiac output. Signs of tension pneumothorax include severe respiratory distress, tracheal deviation to the unaffected side, cyanosis, muffled heart sounds, and possibly cardiac arrest.

The risks for pneumothorax include factors that compromise pulmonary function, such as COPD and smoking. Chest trauma, bronchoscopy, cardiopulmonary resuscitation, central line insertion, and mechanical ventilation using positive end-expiratory pressure pose a risk as well.

A range of reasons for chest tube placement

Condition Possible causes Where the tube is placed

Pneumothorax Air in the pleural space that limits lung expansion. Tension pneumothorax is air that continues to increase pressure and decreases lung expansion, venous return, and cardiac output.

* Trauma, surgery, invasive pulmonary procedures, bronchoscopy

* Forceful coughing or rupture of a bleb in the lung: spontaneous pneumothorax

* Procedures such as percutaneous needle puncture or central line insertion: iatrogenic pneumothorax

Anteriorly near the apex of the lung at the second intercostal space (ICS), midclavicular line

Hemothorax An accumulation of blood in the pleural space. Usually it's a combination of both air and blood, called hemopneumothorax.

Open chest procedures, blunt or penetrating trauma

Two chest tubes may be inserted, one at the apex and one at the base of the lung.

Pleural effusion An abnormal fluid collection or transudation in the pleural space

Heart failure, surgery, malignancy Posteriorly into the fifth or sixth ICS

Empyema A collection of purulent material in the pleural space

Pneumonia, lung abscess, or contamination or injury of the pleural cavity

Posteriorly into the fifth or sixth ICS

Prevention of cardiac tamponade after open-heart surgery Blood that could cause cardiac tamponade if not removed from the mediastinum

Bleeding associated with surgery The clinician may insert anterior and posterior chest tubes attached to the same drainage device using a Y connector or to two separate drainage devices.

Signs and symptoms tell the story

Early on, a patient with pneumothorax may complain of pleuritic chest pain and exhibit anxiety and tachycardia. Monitor Mr. Williams for decreased breath sounds and decreased chest expansion on the affected side. Assess also for an increased respiratory rate and worsening pain when he tries to take a deep breath.

With a tension pneumothorax, the patient may develop distended neck veins, hypotension, subcutaneous emphysema (crepitus), and a shift in the heart's point of maximal impulse. (Its normal location is at the fifth intercostal space, midclavicular line.) He could die of cardiovascular collapse and pulseless electrical activity as the increased intrathoracic pressure prevents his heart from pumping.

A straight chest tube may be used to drain the pleural cavity, and a bent tube is appropriate for the mediastinum.

The decision to insert a chest tube is based on the amount of lung collapse. The pulmonologist determines that Mr. Williams needs a chest tube and CDU to restore normal intrapleural pressure.

Looking at chest tubes and drainage systems

A chest tube drains into a CDU or Heimlich valve, depending on the nature of the patient's problem. Let's look at each component.

Chest tube. A sterile, flexible, nonthrombogenic catheter of vinyl or silicone, a chest tube measures about 20 inches (50 cm) long and has a diameter anywhere from #12 to #40 French. The diameter selected depends on the patient's condition. Size #12 to #26 French is adequate for a pneumothorax, but a wider tube, from #28 to #40 French, is needed to drain accumulated fluid, such as from a pleural effusion. The tube's proximal end, which rests in the pleural space, has several eyelets--small holes--to drain air or fluid and to prevent catheter occlusion. The distal end connects to the CDU.

Chest drainage unit. All CDUs incorporate three basic components: a collection chamber, a water-seal chamber, and a suction-control chamber or regulator. (See How a Chest Drainage Unit Works .)

How a chest drainage unit works

All chest drainage units (CDUs) incorporate three basic components:

Collection chamber. Fluid drains into the chest tube, through a 6-foot (180-cm) connecting tube, and then into the CDU's collection chamber (which holds up to 2,000 ml). Here you can assess the amount, rate, and characteristics of the drainage. Most units also have a port for obtaining samples.

Water-seal chamber. This acts as a one-way valve so air can drain from the chest cavity but can't return to the patient. Think of a cup of water with a straw in it. If you blow into the straw, air bubbles out through the water; if you try to draw air in, you get water. In the same way, as the water seal evacuates air from the chest cavity, the air passes through the column and bubbles into the bottom of the water seal. You can use the water-seal chamber to monitor your patient's intrapleural pressure. The water level fluctuates as the pressure changes. Suction-control regulator. Water-filled or dry suction removes chest drainage and maintains the flow. To regulate suction, connect the CDU's vacuum line tubing to wall suction and set the CDU suction to the ordered level. Water-suction system

A water-filled suction chamber regulates suction by the amount of water in the chamber. When you set up the CDU, fill the chamber to the appropriate level, usually -20 cm H2O for a simple pneumothorax. As the water evaporates, suction decreases, so regularly assess and refill the chamber to the ordered level. Dry-suction system

Dry suction provides more consistent flow because the regulator automatically adjusts suction to changes in the patient's pleural pressure or fluctuations in wall suction pressure. The regulator on a dry-suction CDU is preset to -20 cm H2O, but the level can range from -10 to -40 cm H2O. You'd need to adjust the regulator to change the level.

Heimlich valve. If the patient has a small, uncomplicated pneumothorax with little or no drainage that doesn't require suction, his chest tube may be connected to a Heimlich valve instead of a traditional CDU. Less expensive and easier to assemble and use, this device is essentially a water-seal chamber connected to the chest tube.

A Heimlich valve may be included in the chest tube insertion kit. At its distal end are 'flutter' leaflets that allow air to exit but not reenter the pleural space.

Protect your patient before insertion

Now that the pulmonologist has confirmed Mr. Williams' problem, you have plenty to do. Closely monitor his vital signs and breath sounds and make sure he has intravenous access. Administer 2 to 4 liters/minute of oxygen via nasal cannula and monitor his pulse oximetry. Adjust the FIo2 to a target Spo2 of 94%; remember that an Spo2 of less than 90% usually correlates with a Po2 of 60 mm Hg. If your patient has COPD, monitor his respirations as you increase his oxygen: A higher Po2 level could decrease his respiratory drive.

Promoting chest expansion and intercostal muscle use eases breathing, so keep the head of Mr. Williams' bed at 30 degrees or higher. Watch for changes in his level of consciousness, orientation, and responsiveness. Be alert to anxiety, restlessness, and central cyanosis, which can be early signs of hypoxemia.

Poor oxygenation can affect cardiac rhythm, so attach Mr. Williams to a cardiac monitor. Initially, he may have tachycardia from activation of the sympathetic nervous system that occurs with respiratory distress and inadequate oxygenation. You also may see new-onset premature atrial or ventricular beats.

The clinician will probably order a chest X-ray and arterial blood gases (ABGs) to confirm pneumothorax. The chest X-ray is the definitive diagnostic tool, showing black areas where the lung is collapsed. Initially, the ABGs will reveal respiratory alkalosis caused by tachypnea, but if Mr. Williams' respiratory status worsens, you'll note hypoxemia, hypercapnia, and acidosis.

Prepare the patient and the equipment

When the clinician decides to insert a chest tube, do the following:

Gather the equipment. Besides the chest tube and CDU, you'll need povidone-iodine solution; sterile masks, gloves, and drapes; local anesthetic (usually 1% lidocaine); and personal protective gear, including goggles and impervious sterile gowns. Most hospitals provide preassembled chest tube insertion trays with all the necessary items for the sterile field.

Prepare the CDU . Consult the manufacturer's instructions and follow hospital policy. Each model provides systematic instructions for setup and operation, along with warnings and precautions. Assemble the suction source and connecting tubing. Place the CDU upright and at least 1 foot (30 cm) below the patient's chest level. Use the attached stand to place it on the floor or hang it on the bed's footboard.

To prepare the CDU, add sterile water to the water-seal chamber according to the manufacturer's instructions.

Keep the head of your patient's bed elevated to 30 degrees or higher. Place the CDU upright and at least 1 foot (30 cm) below his chest level.

Perform a baseline cardiopulmonary assessment. This will help you evaluate Mr. Williams' response to treatment. Assess his vital signs, breath sounds, chest excursion, skin color, Spo2, level of consciousness, and cardiac rhythm. Also check any pertinent lab work, such as ABGs and coagulation profile.

Explain the procedure to the patient. He'll probably be anxious and in pain, so administer pain medication or sedation as ordered. Place him in high Fowler's or semi-Fowler's position. Tell him to remain as still as possible and to breathe normally during the procedure. Answer his questions and offer reassurance. Make sure a signed consent form for the procedure is in his chart.

Assisting with chest tube insertion

The clinician will drape and prepare the insertion site with povidone-iodine solution. After injecting a local anesthetic, he'll make a skin incision about 1 inch (2.5 cm) long, then insert a hemostat through it to enter the pleural space. With his finger, he'll create a tract for the chest tube. Then he'll clamp the tube with hemostats, insert it, and advance it so that the distal eyelet is 2 inches (5 cm) inside the pleura.

Once the tube is inserted but before you start suction, attach the patient-connecting tube to the drainage device. Secure the chest tube to the connecting tube using tape or nylon bands, according to hospital policy. Avoid dependent loops in the drainage tubing.

Attach the wall suction line to the suction connector on top of the CDU. Adjust the CDU suction to the level the clinician specifies, usually 20 cm H2O. Set the wall suction pressure to 80 mm Hg or greater until the display on the suction-control chamber confirms adequate suction. Wall suction must have at least 80 mm Hg of vacuum to operate the system efficiently at 20 cm H2O. If multiple drains, such as two mediastinal tubes, are connected to a single suction source, you'll need more vacuum.

After your patient's chest tube is functioning properly, the clinician will suture it in place. If he notes an air leak, he'll wrap petrolatum gauze around the site. However, continued use of petrolatum gauze or ointments can macerate the skin, so these products shouldn't be used routinely.

Dress the insertion site by placing one sterile split-drain sponge over the top of the chest tube and one underneath. Then place sterile 4x4 gauze pads over the drain sponges and secure with 2-inch (5-cm) tape.

Never let the drainage tube dangle. As part of your routine care, make sure it's coiled on the bed.

Dress the site with sterile split-drain sponges covered by sterile 4*4 gauze pads and secure the gauze with 2-inch (5-cm) tape. Mr. Williams will need a portable chest X-ray to verify proper tube placement.

Document the following:

your cardiopulmonary assessments before and after the procedure chest tube size and insertion site the insertion date and time who inserted the tube whether drainage was present and the amount, color, and type your patient's tolerance to the procedure medications he received during the procedure results of his postinsertion chest X-ray your patient and family teaching. Assess your patient and prevent complications

The less time a patient has a chest tube in place, the smaller his chance for complications, such as infection. Here's what you can do to protect him while he's in your unit:

Assessments. Assess his cardiopulmonary status at least every 4 hours. Examine the chest tube insertion site every 8 hours for inflammation, signs of infection, or subcutaneous emphysema. (See Pinpointing Subcutaneous Emphysema. ) Get daily chest X-rays as ordered to check for lung reexpansion.

Dressing changes. Change the dressing on the insertion site as ordered or according to your facility's policy. If it's dry and you don't see evidence of infection, you probably won't change it until the third day after insertion.

Promoting drainage and lung expansion. Encourage your patient to cough and breathe deeply. Teach him how to splint the insertion site and make sure you administer pain medications as needed.

Encourage him to change position at least every 2 hours. He can lie on the side with the chest tube if he can keep the tubing free of kinks. The patient's position influences drainage, so don't be alarmed if you note a sudden gush of output the first time he sits up. If he has a hemothorax, pleural effusion, or empyema and he's been supine for a while, this is old drainage coming out of the pleural space. If he's well enough to walk in the hall, ask the clinician if you can

interrupt suction and encourage him to ambulate as desired.

Monitoring output. Monitor and record the amount and characteristics of the chest tube drainage as ordered or according to your unit's policy, usually every 2 to 4 hours. Notify the clinician of excessive output. Coil the tube on the bed if you notice it dangling.

When your patient has a pneumothorax, expect little if any output because the tube is draining air, not fluid. But if he has a hemothorax, a lack of drainage may indicate a clot obstructing the tube. If that occurs, try milking the tube: Starting at the proximal end, gently squeeze and release it between your fingers along the length of the tubing.

However, don't 'strip' the chest tube, which means squeezing the length of the tube without releasing it. Once a common practice, stripping the tube causes a dangerous increase in intrathoracic pressure and doesn't lead to any significant increase in output.

To milk the tube, start at the proximal end and gently squeeze and release along its length betweenyour fingers.

Monitoring the water-seal chamber. Pay close attention to tidaling, bubbling, and negative pressure.

* Tidaling indicates fluctuations in the water-seal chamber's fluid level that correspond with respiration. On inspiration, increased negative pressure in the pleural cavity increases the water level. On expiration, decreased pleural pressure decreases the water level. Shallow breathing causes less fluctuation and labored breathing causes more.

Pinpointing subcutaneous emphysema

A collection of air or gas under the skin, subcutaneous emphysema--crepitus--is usually painless and feels spongy on palpation. Small amounts of subcutaneous emphysema around the tube insertion site are commonly absorbed. However, if the tube is improperly placed or has an air leak, air may move from the insertion site into the neck, chest, and face and cause pain. In this case, notify the clinician.

Tidaling fluctuations reverse when the patient's breathing is assisted by positive-pressure mechanical ventilation. Because the respiratory pressures are reversed, the water level decreases during inspiration and increases during expiration.

If your patient's lung fully expands or the tubing becomes obstructed, you may not see any fluctuations. You won't see them with a mediastinal chest tube either; breathing doesn't affect a tube that's outside the pleural space.

* Bubbling in the bottom of the water-seal chamber indicates an air leak, caused most commonly by poor tubing connections. You may notice a small amount of bubbling right after chest tube insertion or when the patient exhales or coughs.

When bubbling is present, watch the pattern. If the patient's pleural space is leaking air, you'll notice intermittent bubbling, usually corresponding to his respirations. This should resolve as his lung reexpands. If bubbling in the water-seal chamber is continuous, suspect a leak in the system. To locate the source, such as a loose connection or a nonocclusive dressing, assess from the insertion site to the CDU.

If you're having trouble finding an air leak, try clamping the tubing momentarily at various points along its length. Using rubber-tipped hemostats, start at the proximal end and work your way down. Bubbling will stop when you clamp between the air leak and the water seal. If you've clamped along the tube's entire length and still can't find the source, the CDU might be cracked and need to be replaced.

* Negative pressure in the water-seal column indicates negative pressure in the pleural space--the goal of chest tube therapy. Normally, a water level 2 cm above the water-seal chamber is a sign that the pneumothorax is resolving.

Spotting signs of improvement

As your patient's pneumothorax begins to resolve, he'll have less dyspnea on exertion and less chest pain on inspiration (unless the tube itself causes discomfort). Removing his chest tube is appropriate when a chest X-ray shows that his lungs have reexpanded, his respiratory status has returned to normal, and the drainage over the previous 24 hours is less than 100 ml.

Before deciding to remove the tube, the clinician may order it placed on 'water seal.' This simply means discontinuing suction, generally 24 hours before the anticipated removal. To do this, detach the wall suction tubing from the CDU. Don't clamp the chest tube before discontinuing suction because it could cause your patient's lung to collapse. Closely observe for deterioration in his respiratory status while his chest tube is on water seal: His lung may not remain inflated or he could develop another pneumothorax.

To assist with chest tube removal, gather the necessary supplies, including personal protective equipment because blood splattering is likely. Explain the procedure to the patient and premedicate him for pain at least 15 minutes beforehand. Tell him that he'll need to take a deep breath and hold it when instructed; warn him to expect some pain as the tube is removed.

Once the chest tube is removed, dress the site with a sterile occlusive dressing and dispose of the tube and CDU in the appropriate receptacle. Observe your patient for any changes in respiratory status and make sure he has a portable chest X-ray to ensure that his lung has expanded.

Mastering techniques

Using chest tubes and CDUs is a complex and critical nursing function. By learning about their components and the techniques needed to use them, you've protected your patient and helped him recover from a serious pulmonary problem.

Frequently asked questions about chest drainage units

Q: What if the chest tube becomes dislodged? A: Immediately cover the site with a dry sterile dressing and call the clinician. If you hear air leaking from the site, tape the dressing on only two or three sides to allow air to escape and prevent a tension pneumothorax. Closely monitor the patient and prepare for insertion of a new chest tube.

Q: What if the chest tube becomes disconnected from the chest drainage unit (CDU) or the CDU breaks? A: Submerge the chest tube's distal end in 1 inch (2.5 cm) of sterile 0.9% sodium chloride solution or water in a sterile container. This will create a liquid seal until you prepare and attach a new CDU. Securing the tube connections and properly positioning the CDU help prevent disconnection or breakage.

Q: When should I change the CDU? A: Change it if it breaks or it's full:

Prepare the new CDU according to the manufacturer's instructions. Remove the current CDU from suction, clamp the chest tube with a rubber-tipped hemostat, and disconnect the connecting tube from the CDU. Quickly connect the new CDU, unclamp the tube, and secure all connections according to your unit's policy. Resume suction and assess the CDU chambers for normal function.

SELECTED REFERENCES

A Personal Guide to Managing Dry Suction Chest Drainage. Hudson, N.H., Atrium Medical Corp., 1999.

Blank-Reid, C., and Reid, P.: 'Taking the Tension Out of Traumatic Pneumothoraxes,' Nursing99. 29(4):41-46, April 1999.

Lazzara, D.: 'Respiratory Distress: Loosening the Grip,' Nursing2001. 31(6):58-63, June 2001.

Lynn-McHale, D., and Carelson, K., eds: AACN Procedure Manual for Critical Care, 4th edition. Philadelphia, Pa., W.B. Saunders Co., 2001.

Deborah Lazzara is a cardiology clinical nurse specialist in the cardiac care center at the University of Chicago (Ill.) Hospitals.

Photos by Gary Donnelly

SELECTED WEB SITES

Pneumothorax.orghttp://www.pneumothorax.org/pneumo.nsf

Yale University School of Medicine, cardiothoracic imaging: tension pneumothoraxhttp://info.med.yale.edu/intmed/cardio/imaging/cases/pneumothorax_tension/

Last accessed on May 2, 2002.