Respiratory Study Guide for the CCRN

Pleural Space Abnormalities

Pleura is the outer and inner layer of tissue that covers the outside of the lungs and the chest wall. In between these two layers is referred to as the pleural space that contains a small amount of lubricating fluid called pleural fluid. Injury, inflammation, or infection can cause issues with the pleura tissue itself and/or allow for the buildup of bacteria, air, fluid, or blood within the pleural space.

Pneumothorax

Air-leak syndromes are an acute condition that may result from trauma or spontaneous alveoli rupture. In this event, pressure builds in the alveoli sacs until the wall of these structures pulls away from the perivascular tissue. This separation of the alveolar wall and the perivascular sheath causes alveoli rupture and collapse as air exits the lungs into the perivascular space.

The medical term for an air leak into the pleural cavity is pneumothorax. Lung collapse may be partial or complete and can be defined by the location of the displaced air and how the alveoli rupture occurred. There are four primary locations of air displacement in the event of pneumothorax. Air in the pleural cavity is simply called a pneumothorax. Air in the pericardial sac is known as pneumopericardium, and air in the peritoneal cavity is known as pneumoperitoneum. If the air extends to the subcutaneous tissue, noted by a crackling feeling with palpation or the superficial tissues, the event is known as subcutaneous emphysema or crepitus.

A pneumothorax may be spontaneous, traumatic, or iatrogenic (medically acquired due to prior intervention).

• A spontaneous pneumothorax occurs despite any predisposing events and may either be primary or secondary. Primary spontaneous pneumothorax occurs in healthy lungs, whereas secondary spontaneous pneumothorax occurs in diseased lungs with structural alveolar changes.

• Traumatic pneumothorax occurs due to injury to the chest wall, lung, or pleural space. It may be direct or indirect based on the injury that occurred. Tension pneumothorax occurs when air continues to enter the pleural space with every inspiration, but is unable to escape during expiration. Signs of this include tracheal deviation and changes in hemodynamic status, and are most commonly caused by traumatic lung injuries. A tension pneumothorax is a true medical emergency that needs to be treated immediately as the increased thoracic pressure can cause decreased cardiac output and ultimately sudden cardiac arrest.

• Finally, iatrogenic pneumothorax occurs when air leaks from the alveolar tissues due to medical interventions. Iatrogenic pneumothorax may result from barotrauma/volutrauma, placement of a subclavian central line, or cardiac/thoracic surgical procedures.

Symptoms

Symptoms may vary; however, the most common symptom is acute pleuritic pain, usually on the affected side. Pleurisy is caused by the inflammation of the pleura causing the layers to rub together which leads to the sharp chest pain worse on inspiration or coughing. Nurses may also assess for decreased breath sounds and asymmetrical chest expansion. The patient may also have dyspnea, cyanosis, and tachypnea. A chest X-ray is frequently used to assess for and diagnose pneumothorax. An ultrasound may also be used to identify any pneumothorax following a traumatic event.

Treatment

Most pneumothorax events are treated with a water-seal chest-tube thoracostomy system. This tube is inserted by a trained provider in between the patient’s ribs and connected to an external drainage system. This drainage system has a water seal that works as a one way valve to let air out and also prevent it from going back in. Nurses have an important role in assessing the chest tube insertion site and chamber. The insertion site should be covered by an occlusive dressing. In the event that the chest tube comes out, the incision needs to be immediately covered to prevent air from entering.

On the drainage system’s chamber itself, you should note tidaling which is a normal fluctuation with inspiration and expiration. However, continuous bubbling can indicate an air leak. The drainage system should always remain below chest level and remain connected. Ensure no kinks or loops in the tubing. Chest tubes typically will remain in place for a few days and a repeat chest X-ray is taken to see if the pneumothorax has improved.

In the event of a tension pneumothorax, an acute needle decompression should be performed prior to chest tube insertion. Some patients with small pneumothorax events may be provided with oxygen therapy and observed for several hours. If a repeat X-ray after six hours shows no worsening of the air accumulation, the patient may be discharged home and instructed to have a follow-up X-ray in 24 hours.

Hemothorax

Hemothorax occurs when blood enters the pleural space. This occurs most commonly due to chest trauma; however, it can also be caused as a result of damage to the pleural space from medical interventions, infarction of the lung tissue, tuberculosis, or cancer growth. Symptoms of hemothorax include chest pain, anxiety/sense of impending doom, decreased blood pressure, increased work of breathing, shortness of breath, and cool clammy skin. Patients may experience hemodynamic instability, shock, and respiratory compromise.

Diagnosis and Treatment

Diagnosis of hemothorax is usually determined by chest X-ray or CT scan. Testing of the pleural fluid may also be performed to determine the composition of the fluid (bloody generally indicates hemothorax). A chest tube should be inserted and set to suction to drain the pleural space. This may also be used to attempt to treat the bleeding. However, if the bleeding is not stopped, a thoracotomy may be required to investigate the lung tissues and pleural space. Depending on the severity and cause of the hemothorax, other medical interventions may include oxygen support (ranging from nasal cannula to endotracheal tube placement), blood transfusion, and hemodynamic support.

Nurses must monitor patients with hemothorax closely. The same considerations and assessments should be completed for the chest tube as patients with a pneumothorax with the addition of monitoring drainage. Chest tube drainage color and amount should be measured every one to two hours. Drainage greater than \(150\) mL/hr for two to four hours may indicate continued/active bleeding that must be addressed by a healthcare provider.

Empyema

Empyema is the presence of pus or infection in the pleural cavity. It can occur secondary most commonly to pneumonia, but also can be caused by hemothorax, parapneumonic effusion, trauma, post-thoracic surgery, or esophageal rupture. It may also occur as a primary infection, though this is less common. Patients at higher risk for empyema include those with diabetes mellitus, immunosuppression, acid reflux, IV drug abuse, and alcohol abuse.

Symptoms and Diagnosis

Symptoms and diagnosis of empyema is similar to pneumonia. Patients may exhibit symptoms such as shortness of breath, cough, decreased lung sounds, shallow breathing patterns, sputum production, fever, and chest pain. If antibiotic therapy is not improving a patient’s symptoms within a few days, the occurrence of empyema should be considered. Diagnosis can be obtained with chest X-ray, chest CT, pleural ultrasound, and/or pleural fluid culture.

Treatment

To treat empyema, the pus and infected pleural fluid must be drained and treated. A percutaneous thoracentesis can often be used in simple cases of empyema to drain the pus through a needle inserted into the pleural space. Some patients will require chest-tube placement to help drain the pus. Antibiotic therapy should be started or continued for several weeks (generally two to six weeks). Intrapleural medication injection is generally not used. Surgical intervention via video-assisted thoracoscopic surgery (VATS) or open thoracotomy may be required if the infection persists despite the previous measures.

Pleural Effusion

Fluid collection in the pleural space is known as pleural effusion. Pleural effusion may be caused by viral infection, pneumonia, or heart failure. It can also be secondary to cancer, radiation, or thoracic surgery. Symptoms of pleural effusion include chest pain, nonproductive cough, shortness of breath, and orthopnea.

Diagnosis

Two types of pleural effusion can be diagnosed. These are transudative pleural effusion and exudative effusion.

• Transudative pleural effusion is most commonly caused by heart failure. This is due to increased blood vessel pressures or low blood protein pushing fluid into the pleural space. Transudative pleural fluid is characteristically watery.

• Exudative effusion is caused by blocked blood or lymph vessels related to inflammation, infection, injury, or obstruction (blood clot, tumor, plaques, etc.). Exudative effusion fluid is characteristically protein rich.

Diagnosis of pleural effusion can be made via chest X-ray, CT scan, or thoracic ultrasound. If the effusion is large, an X-ray can show mediastinal shift towards the opposite side can be observed.

Treatment

A thoracentesis may be performed to determine the fluid contents and drain some of the existing fluid. Typically about a liter can be removed in one session. Rapid removal of large volumes of fluid can cause hypotension and pulmonary edema. Some patients will require chest tube placement to drain remaining fluid and help re-expand the lung tissue(s). Patients must have any underlying conditions/causes to the pleural effusion treated to reduce the chances of effusion recurrence. Surgical intervention via video-assisted thoracoscopic surgery (VATS) or thoracotomy (open thoracic surgery) may be required to address the fluid leak.

Anatomic Pulmonary Changes

Pulmonary changes may occur due to chronic or acute pulmonary illness. The two most common changes to occur include pulmonary fibrosis and pulmonary hypertension. These diagnoses will be reviewed in the upcoming sections.

Pulmonary Fibrosis

Pulmonary fibrosis is scarring of the lung tissue. It is usually an idiopathic condition. The scar tissue causes the lungs to thicken, which in turn reduces adequate oxygen exchange. It is a progressive condition and the average survival rate is five years after diagnosis. While there is no known direct cause of pulmonary fibrosis, it may be associated with environmental exposures (asbestos, smoke, wood dust, metal dust) or genetics. People between the ages of 40 to 70 and men, more often than women, will acquire this condition.

Diagnosis and Treatment

Symptoms of pulmonary fibrosis include dry cough, shortness of breath, fatigue, weight loss, and fingertip and nail clubbing. It can be diagnosed by physical assessment, chest X-ray, CT, PFTs, and biopsy. There is no cure for pulmonary fibrosis, and patients are offered minimal supportive options. The prognosis is poor with a median survival rate less than five years. Oxygen therapy may be initiated when hypoxemia becomes a concern. Lung transplant may be considered for some patients as well.

Pulmonary Hypertension (PH)

PH is defined as high blood pressure in the arteries of the pulmonary system and heart. This is usually caused by damage to or obstruction of the pulmonary vascular bed that impairs the vessels’ ability to easily receive blood from the right ventricle. Increased pulmonary arterial pressure leads to increased pulmonary vascular resistance. This puts increasing pressure on the right ventricle and, over time, will cause hypertrophy of the chamber. As the right ventricle remodels, the interventricular septum deviates and creates tricuspid regurgitation. This is known as cor pulmonale. If left untreated, progressive right heart failure and eventually death will occur.

Diagnosis

Echocardiogram is typically the initial diagnostic as it is noninvasive and can provide some data to support the diagnosis of pulmonary hypertension. However, right-sided heart catheterization is most definitive and can confirm the suspected diagnosis. A mean pulmonary artery pressure greater than \(20\) mmHg is diagnostic for pulmonary hypertension.

Pulmonary hypertension is an umbrella term and refers to this elevation in pressure from any cause. Pulmonary arterial hypertension (PAH) is a specific category within this in which the pulmonary arteries themselves are damaged which can be due to a variety of factors. Diagnostic criteria includes the elevated pulmonary artery pressure (PAP) greater than 20 mmHg as mentioned previously but also includes a pulmonary artery wedge pressure (PAWP) less than 15 mmHg and a pulmonary vascular resistance (PVR) greater than 3 Woods units.

Pulmonary arterial hypertension is classified as group one in the World Health Organization’s five groups of clinical classification for pulmonary hypertension. Previously referred to as primary and secondary PAH, now is further broken down into the following clinical classifications:

• idiopathic (no known cause)
• heritable (genetics)
• drug and/or toxin-induced
• associated with the following conditions:
  • connective tissue disease
  • HIV infection
  • portal hypertension
  • congenital heart disease
  • schistosomiasis
• PAH with features of venous/capillary involvement
• persistent PH of the newborn

Once diagnosed with PAH, the patient is scored from 1 to 4 on functional ability and therefore, severity of disease, with 1 being no symptoms or limitations and 4 being severe activity intolerance.

The other groups of this classification include:

• group two—PH due to left heart disease
• group three—PH due to lung diseases or hypoxia
• group four—Chronic thromboembolic PH
• group five—PH with multifactoral/unclear mechanisms

Treatment

Treatment of pulmonary hypertension and pulmonary arterial hypertension includes treating the underlying cause, controlling cardiac and pulmonary symptoms, and preventing complications.

• Pharmacologic therapy most commonly includes the use of an endothelin receptor antagonist (ERA) such as ambrisentan (Letaris®) or macitentan (Opsumit®) in and/or a phosphodiesterase-5 inhibitor (PDE-5i) such as sildenafil (Revatio®). Common pulmonary vascular dilators can also be used and include IV epoprostenol (Flolan®) and subcutaneous treprostinil sodium (Remodulin®). Some patients may respond to high-dose calcium channel blockers. These medications can be used to both control symptoms and prolong life. Anticoagulant therapy may be used to prevent pulmonary emboli. Diuretics may be used to reduce the pulmonary fluid burden and peripheral edema.

• Oxygen therapy may be initiated if hypoxemic.

If pharmacologic therapy does not reduce the patient’s symptoms and manage their pulmonary hypertension adequately, a heart-lung transplant may be considered to improve the rate of survival.