Eliminate the air of mystery from chest tubes

Nursing, Jun 2002 by Lazzara, Deborah

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

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 Spot 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.

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.

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 patients 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 patients 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.)

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.