Pneumothorax

a 30-year-old woman became dyspneaic after falling down stairs...

Introduction

Background

Pneumothorax is defined as the presence of air or gas in the pleural cavity. Primary spontaneous pneumothorax (PSP) occurs in people without underlying lung disease and in the absence of an inciting event. Many patients whose condition is labeled as primary spontaneous pneumothorax have subclinical lung disease.

Secondary spontaneous pneumothorax (SSP) occurs in people with a wide variety of parenchymal lung diseases. Iatrogenic pneumothorax results from incursion into the pleural space secondary to diagnostic or therapeutic medical intervention. Traumatic pneumothorax results from injury, typically blunt or penetrating trauma. Tension pneumothorax develops when air is trapped in the pleural cavity under positive pressure.¹ 

This article identifies several areas of new information in the medical literature: 1) studies comparing aspiration and tube drainage for treatment of primary spontaneous pneumothorax, 2) long term follow-up of surgical treatment of pneumothorax, 3) assessment of the impact of pleurodesis on transplantation outcomes in patients with lymphangiomyomatosis, 4) demonstrated utility of ultrasonography in the bedside diagnosis of iatrogenic pneumothorax, and 5) inability of ultrasonography to distinguish between intrapulmonary bullae and pneumothorax.

Pathophysiology

The inner surface of the thoracic cage (parietal pleura) is contiguous with the outer surface of the lung (visceral pleura); this space contains a small amount of lubricating fluid and is normally under negative pressure compared to the alveoli. Determinants of pleural pressure are the opposing recoil forces of the lung and chest wall.

Primary spontaneous pneumothorax (PSP) is typically observed in tall young people without parenchymal lung disease and is thought to be related to increased shear forces in the apex. PSP is associated with the presence of apical pleural blebs lying under the visceral pleura, but the exact anatomic site of air leakage is often uncertain. Fluorescein-enhanced autofluorescence thoracoscopy (FEAT), a novel method to examine the site of air leak in PSP, shows FEAT-positive lesions that are normal when viewed under normal white-light thoracoscopy.² 

Blebs and bullae (sometimes called emphysematous-like changes or ELCs) are related to the occurrence of primary spontaneous pneumothorax. Thoracic computerized tomography (CT) of patients with PSP shows ipsilateral ELC in 89% and contralateral changes in 80% compared to a rate of 20% among control subjects matched for age and smoking. Nonsmokers with PSP had CT ELC abnormalities of 80% compared with a rate of 0% among nonsmoker controls without PSP.¹ 

While patients with PSP do not have overt parenchymal disease, more than 90% of them are smokers. The relative risk of PSP increases as the number of cigarettes smoked per day increases. This incremental risk with increasing number of cigarettes smoked per day is much more pronounced in female smokers.

Lung inflammation and oxidative stress are hypothesized to be important to the pathogenesis of PSP.³ Current smokers, at increased risk for PSP, have increased numbers of inflammatory cells in the small airways. Bronchoalveolar lavage studies in patients with PSP associated the degree of inflammation with the extent of ELCs. One hypothesis is that ELCs result from degradation of lung tissue due to imbalances of enzymes and antioxidants released by innate immune cells.⁴ In one study, erythrocyte superoxide dismutase activity was significantly lower and plasma malondialdehyde levels higher in patients with PSP than in normal control subjects.

A growing body of evidence indicates that genetic factors may be important in the pathogenesis of many cases of primary spontaneous pneumothorax. Familial clustering of this condition has been reported. Genetic disorders that have been linked to primary spontaneous pneumothorax include Marfan syndrome, homocystinuria, and Birt-Hogg-Dube (BHD) syndrome.

Birt-Hogg-Dube syndrome is an autosomal dominant disorder that is characterized by benign skin tumors (hair follicle hamartomas), renal and colon cancer, and spontaneous pneumothorax. The spontaneous pneumothorax occurs in about 22% of patients with this syndrome. The gene responsible for this syndrome has been identified and is a tumor suppressor gene located on chromosome 17p11.2. The gene encoding folliculin has been identified and is thought to be the etiology of Birt-Hogg-Dube syndrome. Multiple mutations have been found, and phenotypic variation is recognized. In a recent study, 8 patients without skin or renal involvement had lung cysts and spontaneous pneumothorax. A germ line mutation to this gene has been found in 5 patients. Genetic testing is now available.⁵ 

Secondary spontaneous pneumothoraces (SSP) occur in the presence of lung disease, primarily in the presence of chronic obstructive pulmonary disease (COPD). Other diseases that may be present when SSPs occur includetuberculosis, sarcoidosis, cystic fibrosis, malignancy, and idiopathic pulmonary fibrosis.

Pneumocystis jiroveci pneumonia (previously known as Pneumocystis carinii pneumonia [PCP]) was a common cause of secondary spontaneous pneumothorax in patients with AIDS during the last decade. With the advent of highly active antiretroviral therapy (HAART) and widespread use of trimethoprim-sulfamethoxazole prophylaxis, the incidence of PCP and associated SSP has significantly declined. 

PCP is now primarily seen in patients who are noncompliant with HIV therapy or trimethoprim-sulfamethoxazole prophylaxis or those taking inhaled pentamidine for PCP prophylaxis (probably related to nonuniform distribution of the medication aerosol). PCP in other immunocompromised patients is seen only when trimethoprim-sulfamethoxazole prophylaxis is withdrawn prematurely. For practical purposes, if the immunocompromised patient has been taking trimethoprim-sulfamethoxazole prophylaxis reliably, PCP is reasonably excluded from the differential diagnosis.

Iatrogenic pneumothorax is a complication of medical or surgical procedures. It most commonly results from transthoracic needle aspiration. Other procedures commonly causing iatrogenic pneumothorax are therapeutic thoracentesis, pleural biopsy, central venous catheter insertion, transbronchial biopsy, positive pressure mechanical ventilation, and inadvertent intubation of the right mainstem bronchus. Therapeutic thoracentesis is complicated by pneumothorax 30% of the time when performed by inexperienced operators in contrast to only 4% of the time when performed by experienced clinicians.

The routine use of ultrasonography during diagnostic thoracentesis is associated with lower rates of pneumothorax (4.9% vs 10.3%) and need for tube thoracostomy (0.7% vs 4.1%). Similarly, in patients who are mechanically ventilated, thoracentesis guided by bedside ultrasonography without radiology support results in a relatively lower rate of pneumothorax.

Traumatic pneumothoraces can result from both penetrating and nonpenetrating lung injuries. Complications include hemopneumothorax and bronchopleural fistula. Traumatic pneumothoraces can create a 1-way valve in the pleural space (only letting in air without escape) and can lead to a tension pneumothorax.

Tension pneumothorax typically occurs in the intensive care setting in patients who are ventilated. With air trapping in the pleural space, positive pressure rises. This pressure compresses the mediastinum, decreasing venous return to the heart and reducing cardiac output. In addition, owing to ipsilateral lung collapse and contralateral lung compression, gas exchange is compromised, leading to hypoxemia.

Frequency

United States

For men, the age-adjusted incidence of primary spontaneous pneumothorax (PSP) is 7.4 cases per 100,000 persons per year. For women, age-adjusted incidence is 1.2 cases per 100,000 persons per year.⁶

For men, the age-adjusted incidence of secondary spontaneous pneumothorax (SSP) is 6.3 cases per 100,000 persons per year; for women, age-adjusted incidence is 2.0 cases per 100,000 persons per year. In patients with COPD, the incidence is 26 cases per 100,000 patients per year.⁷

Traumatic pneumothoraces occur more frequently than spontaneous pneumothoraces, and the rate is increasing.

Mortality/Morbidity

Recurrences usually strike within the first 6 months to 3 years. The 5-year recurrence rate is 28% for primary spontaneous pneumothorax (PSP) and 43% for secondary spontaneous pneumothorax (SSP).

• Recurrences are more common among patients who smoke, patients with COPD, and patients with AIDS. Predictors of recurrence include pulmonary fibrosis, younger age, and increased height-to-weight ratio. Bullous lesions found on CT scan or at thoracoscopy are not predictive of recurrence. In a retrospective study of 182 consecutive patients with a newly diagnosed first episode of pneumothorax, a higher rate of recurrence was noted in taller patients, thin patients, and patients with SSP. Patients who underwent pleurodesis had cumulative rates of recurrence 13%, 16%, and 27% at 6 months, 1 year, and 3 years, respectively, compared to 26%, 33%, and 50%, respectively, in patients treated with chest tube drainage. The use of tetracycline or gentamicin did not have any significant impact on the recurrence rate.
• Complications include hypoxemic respiratory failure, respiratory or cardiac arrest, hemopneumothorax, and bronchopulmonary fistula.
• PSP is typically benign and often resolves without medical attention.
  • While the risk of mortality with PSP is low, a higher risk of mortality with SSP exists. In particular, patients with COPD are at great risk, with a 3.5-fold increase in relative mortality.
  • Studies indicate a mortality rate of 1-17% in patients with COPD and an SSP. One study indicated that 5% of patients with COPD died before a chest tube was placed.
  • Patients with AIDS also have a high inpatient mortality rate of 25% and a median survival of 3 months after the pneumothorax. These data derive from the pre-HAART therapy era (see above).

Sex

For primary spontaneous pneumothorax (PSP), the male-to-female ratio of age-adjusted rates is 6.2:1. For a secondary spontaneous pneumothorax (SSP), the male-to-female ratio of age-adjusted rates is 3.2:1.

Age

• Primary spontaneous pneumothoraces (PSPs) occur in people aged 20-30 years. Peak incidence is in the early twenties, and PSP is rarely observed in people older than 40 years.
• Secondary spontaneous pneumothoraces (SSPs) occur more frequently in patients aged 60-65 years.

Clinical

History

Most episodes of spontaneous pneumothorax (SP) occur at rest. By definition, spontaneous pneumothorax is not associated with trauma or stress.

• Acute onset of chest pain and shortness of breath were present in all patients in one series. Typically, both symptoms are present in 64% of patients.
  • Acute onset of chest pain - Severe and/or stabbing pain, radiating to ipsilateral shoulder and increasing with inspiration (pleuritic)
  • Sudden shortness of breath
• Anxiety, cough, and vague presenting symptoms (eg, general malaise, fatigue) are less commonly observed.
• Dyspnea tends to be more severe with secondary spontaneous pneumothoraces (SSPs) because of decreased lung reserve.
• Bilateral pneumothorax - Primary bilateral spontaneous pneumothorax (PBSP) was significantly more common in patients with lower BMI and among smokers.⁸

Physical

• General appearance
  • Diaphoretic
  • Splinting chest wall to relieve pleuritic pain
  • Cyanotic (with tension pneumothoraces)
• Vital signs
  • Tachypnea
  • Tachycardia (most common finding) - If faster than 135 beats per minute (bpm), tension pneumothorax is likely
  • Pulsus paradoxus
  • Hypotension (often with tension pneumothorax)
  • Asymmetric lung expansion - Mediastinal and tracheal shift to the contralateral side with a large tension pneumothorax
  • Distant or absent breath sounds
  • Hyperresonance on percussion
  • Decreased tactile fremitus
• Cardiovascular - Jugular venous distension (tension pneumothorax)
• Neurologic - Altered mental status
• If patients who are mechanically ventilated are difficult to ventilate during resuscitation, high peak airway pressures are a clue to an impending pneumothorax. A tension pneumothorax causes progressive difficulty with ventilation as the normal lung is compressed. On volume-control ventilation, this is indicated by marked increase in both peak and plateau pressures, with relatively preserved peak and plateau pressure difference. On pressure control ventilation, tension pneumothorax causes sudden drop in tidal volume. However, these observations are neither sensitive nor specific for making the diagnosis of pneumothorax or ruling out the possibility of pneumothorax.

Causes

• Risks factors for primary spontaneous pneumothorax (PSP)
  • Smoking
    • Of patients with PSP, 91% reportedly are smokers or were smokers.
    • The risk of PSP is related to the intensity of smoking, with 102-times higher incidence rates in males who smoke heavily (ie, >22 cigarettes/d), compared to a 7-fold increase in males who smoke lightly (1-12 cigarettes/d).
  • Tall, thin stature in a healthy person
  • Marfan syndrome
  • Pregnancy
    • A 10-year retrospective series of 250 SP cases found 5 pregnant women, suggesting that pregnancy is an unrecognized risk factor.⁹
    • The cases were all managed successfully with simple aspiration or vacuum-assisted thoracostomy (VATS), and no harm occurred to mother or fetus.⁹
  • Familial pneumothorax
    • Familial spontaneous pneumothorax has been described as an autosomal dominant inheritance with incomplete penetrance. One family study reported 9 cases of SP among 54 members ascertained.
    • A review of the literature summarized 61 reports of familial spontaneous pneumothorax among 22 families. Up to 10% patients with SP report a positive family history.¹⁰
• Diseases and conditions associated with secondary spontaneous pneumothorax
  • Chronic obstructive lung disease
  • Asthma
  • HIV/AIDS with Pneumocystis jiroveci (PCP) infection: 77% of AIDS patients with SP had thin-walled cavities, cysts, and pneumothorax from PCP infection.¹¹
  • Necrotizing pneumonia
  • Bronchogenic carcinoma
  • Metastatic malignancy
    • Pneumothorax in a patient with malignancy should prompt a look for metastatic disease. Many different types of malignancies have been implicated, especially sarcomas, but also genitourinary cancers and primary lung cancer.
    • Chemotherapeutic agents and, at times, the response of cancer to the agent can induce SP.¹²
  • Tuberculosis
  • Cystic fibrosis (CF)
    • Up to 18.9% of patients with CF have been reported to have SP and have a high incidence of recurrence on the same side after conservative management (50%) or intercostal drainage (55.2%). The average annual incidence is 1 per 167 each year (Batten 1982).
    • The risk of SP increases with cepacia or pseudomonas infections, allergic bronchopulmonary aspergillosis (ABPA), and lower lung function.¹³ Pleurodesis increases the risk of bleeding associated with lung transplantation but is not an absolute contraindication.
  • Inhalational and intravenous drug use such as marijuana and cocaine has been implicated as etiology of SP as well.¹⁴
  • Interstitial lung diseases associated with connective tissue diseases
    • Ankylosing spondylitis (AS) when apical fibrosis is present: The typically low incidence of SP in patients with AS (0.29%) increases 45-fold to 13% when apical fibrotic disease exists.¹⁵
  • Idiopathic pulmonary fibrosis
  • Sarcoidosis
  • Lymphangioleiomyomatosis (LAM)
    • SP may be the presenting sign of LAM, a disease characterized by thin-walled cysts in women of childbearing age.
    • Respiratory failure may lead to a need for lung transplantation, and prior pleurodesis is no longer an absolute contraindication for lung transplantation.
  • Langerhans cell histiocytosis
  • Acute respiratory distress syndrome (ARDS) and positive pressure ventilation in ICU: High peak airway pressures can translate into barotrauma in up to 3% of patients on a ventilator and up to 5% of patients with ARDS.¹⁶
  • Severe acute respiratory syndrome (SARS): 1.7% of patients with this acute viral syndrome developed SP.¹⁷
  • Thoracic endometriosis
    • In a case series of 229 patients, catamenial pneumothorax caused by thoracic endometriosis was localized to the visceral pleura in 52% of patients and to the diaphragm in 39% of patients.
    • Treatment is almost always surgical; most cases present during or shortly after menses, and the SP is usually right-sided. It occurs mostly in women aged 30-40 years.
    • The risk of thoracic endometriosis can not be predicted from the site of peritoneal lesions.¹⁸
• Causes of iatrogenic pneumothorax
  • Transthoracic needle aspiration biopsy of pulmonary nodules
  • Transbronchial biopsy
  • Thoracentesis
  • Central venous catheter insertion
  • Intercostal nerve block
  • Tracheostomy
  • Cardiopulmonary resuscitation
  • Positive pressure ventilation and ARDS in the ICU: High peak airway pressures can translate into barotrauma-associated pneumothorax in up to 3% of patients on a ventilator and up to 5% of patients with ARDS.¹⁶
  • Acupuncture
  • Nasogastric feeding tube placement
• Causes of traumatic pneumothorax
  • Trauma - Penetrating and nonpenetrating injury
  • Rib fracture
  • High-risk occupation (eg, diving, flying)

Differential Diagnoses

Esophageal Spasm
Myocardial Ischemia
Pericarditis, Acute
Pleurodynia
Pulmonary Embolism

Other Problems to Be Considered

Large bulla can simulate pneumothorax on chest radiographs. CT scan may be required to clarify the diagnosis.

Occasionally, skin folds, the scapula, and bed sheets can mimic the pleural line, falsely suggesting pneumothorax on the chest radiograph.

Workup

Laboratory Studies

• Arterial blood gas - In patients with severe underlying lung disease and in those with persistent respiratory distress despite treatment
  • Hypoxemia occurs with increased alveolar-arterial oxygen tension gradient.
  • Hypoxemia tends to be more severe in patients with secondary spontaneous pneumothoraces.

Imaging Studies

• Chest radiograph (confirms pneumothorax)
  • A linear shadow of visceral pleura with lack of lung markings peripheral to the shadow may be observed, indicating collapsed lung.
  • In supine patients, deep sulcus sign with radiolucency along costophrenic sulcus may help to identify occult pneumothorax.
  • Mediastinal shift toward the contralateral lung may also be apparent.
  • Small pleural effusions commonly are present and increase in size if the pneumothorax does not reexpand.
  • Airway or parenchymal abnormalities in the contralateral lung suggest causes of secondary pneumothorax. Evaluation of the parenchyma in the collapsed lung is less reliable.
  • For more information, see eMedicine Radiology article Pneumothorax.
• Method to estimate the fractional size of pneumothorax
  • Calculate the ratio of the transverse radius of the pneumothorax (cubed) to the transverse radius of the hemithorax (cubed).
  • To express the pneumothorax size as a percentage, multiply the fractional size by 100.
  • The cut-point distinguishing small and large pneumothoraces varies somewhat among professional societies and experts. The British Thoracic Society uses 2 cm as the cut-off,¹⁹ the American College of Chest Physicians uses 3 cm as the cut-point,²⁰ and the Light Index uses 15% of the thoracic volume on the posterior-anterior film as the cut point.²¹
• Lateral decubitus film
  • Confirmation of a suspected pneumothorax that is not readily observed on standard supine anteroposterior (AP) radiograph can be demonstrated by obtaining a lateral decubitus film with the involved hemithorax positioned uppermost.
• Rib films
  • Rib films are indicated if the patient has localized rib pain.
  • Rib films are also indicated when evaluating the patient's posttrauma status if nothing is found on the main posteroanterior (PA) and lateral films.
• CT scan
  • CT scan is not recommended for routine use but can help to accomplish the following:
    • Distinguish between a large bulla and a pneumothorax
    • Indicate underlying emphysema or emphysemalike changes
    • Determine the exact size of the pneumothorax, especially if it is small
    • Confirm the diagnosis of pneumothorax in patients with head trauma who are mechanically ventilated
  • CT is widely used in actual clinical practice to assess the possibility of associated concurrent pulmonary disease because of the inherent superiority of CT scans to visualize the details of lung parenchyma and pleura.
• Ultrasonography
  • Ultrasonography is increasingly used in the acute care setting as a readily available bedside tool, especially in ICU and emergency departments.
    • Traumatic pneumothorax in the ICU setting can be followed accurately and early (initial 24 hours) with ultrasonography alone for resolution of the lesion.
    • Lung sliding is the terminology for normal pleural movement in patients without pneumothorax.²² One study showed absent lung sliding from an anterior approach indicated pneumothorax (n =9) with 81% sensitivity and 100% specificity.
  • Ultrasonography has high sensitivity (95.65%), specificity (100%), and diagnostic effectiveness (98.91%) for pneumothorax when using CT as the criterion standard. The sensitivity drops in the ICU, especially in patients with acute respiratory distress syndrome (ARDS).²³
  • Ultrasonography cannot be used to discriminate between a COPD-associated bleb and pneumothorax.²⁴

Treatment

Medical Care

Despite large areas of agreement on management of pneumothorax, a full consensus about management of initial or recurrent pneumothorax does not exist. Professional societies differ in their approach to management and hospitalization.^25,20 

This management section presents a risk stratification framework for choosing among options to restore an air-free pleural space and prevent recurrences.²⁶ While these goals are consistent across diverse clinical presentations, the range of options includes watchful waiting without or with supplemental oxygen, simple aspiration, tube drainage without or with medical pleurodesis, vacuum-assisted thoracostomy (VATS) with pleurodesis and/or closure of leaks and bullectomy, and open surgical procedures such as thoracotomy for pleurectomy or pleurodesis.

Selection among options requires an understanding of the natural history of pneumothorax, the risk of recurrent pneumothorax, and the benefits and limitations of treatment options.

Risk stratification

The decision to observe or to treat with an immediate intervention should be guided by a risk stratification that considers the patient's presentation and the likelihood of spontaneous resolution and recurrence.

• Patient's presentation
  • Asymptomatic (incidental finding): Treatment decisions are guided by estimate of long-term recurrence risk.
  • Symptomatic but clinically stable: Treatment is guided by local resources and conventions for the site of care. The British Thoracic Society (BTS) advocates for simple aspiration and deferring hospitalization in primary spontaneous pneumothorax (PSP) as initial management if stable.²⁵ A small bore catheter or chest tube placement is recommended by the American College of Chest Physicians (ACCP) Delphi consensus statement.²⁰
  • Clinically fragile: Treatment is guided by local practice patterns for air evacuation and observation. Comorbid conditions may preclude observation because of decreased cardiopulmonary reserve.
  • Life threatening: Pneumothorax that causes hemodynamic instability is life-threatening and must be treated immediately with tube thoracostomy. All documents and recommendations call for intervention if a patient is unstable.
• Likelihood of resolution
  • Very likely to resolve - Small pneumothorax in a hemodynamically stable patient without significant parenchymal lung disease; small iatrogenic pneumothorax
  • May resolve - Large pneumothorax in a normal lung (eg, PSP or iatrogenic pneumothorax)
  • Unlikely to resolve - Secondary pneumothorax, enlarging pneumothorax (suggests a continuing air leak)
  • Won't resolve, could be fatal - Tension pneumothorax; unrecognized air leak
• Likelihood of recurrence
  • Unlikely to recur (iatrogenic pneumothorax in normal lung)
  • May recur, but will likely be clinically stable
  • May recur and be clinically unstable but emergency care readily accessible
  • Very likely to recur (diffuse and progressive pulmonary pathology; eg, lymphangioleiomyomatosis [LAM])
  • Recurrence could be life-threatening (poor cardiopulmonary reserve, limited access to emergency medical care)

Selection of site of care

• Outpatient care: This can occur in asymptomatic patients or those with a small pneumothorax and reliable follow-up.
• Emergency department (ED) care: ED care is changing. Prolonged periods of observation are less practical because of large patient volumes; efficacy studies of manual aspiration and placement of one-way valves are based in EDs in an attempt to address these practical issues.
• Inpatient observation: This site of care is generally selected when high-flow oxygen is needed, the pneumothorax is larger but the patient is stable, or comorbidities increase concern about risk or follow-up. The average hospital stay is 2.8 days.
• ICU: ICU treatment and observation is appropriate for patients who are unstable or intubated.

Interval of observation

• No protocols regarding serial radiography or imaging exist; the clinician typically reviews serial vital signs and clinical assessments, using the direction and rate of change in the clinical status to select imaging frequency. Monitoring pneumothorax size during this time is important.
  • 0-6 hours: The ACCP Delphi consensus statement recommends observation in an ED for 6 hours, and discharge to home if a follow-up chest radiograph shows no enlargement of the lesion, in reliable patients.²⁰ Emergency room observation with a repeat radiograph 6 hours later used to be common but may be used less often now.
  • 24-96 hours: Additional follow up in 2 days is recommended, with preference given to a 24-48 hour follow-up radiograph in the outpatient setting. Outpatient follow-up during the 96-h (4-d) window is essential to distinguish between a resolved pneumothorax and one that needs evacuation. A CT scan at this time distinguishes between PSP and secondary spontaneous pneumothorax (SSP).
  • 1 month: Full re-expansion can occur, on average, 3 weeks after the initial event.

Options to restore an air-free pleural space

• Observation without oxygen: Simple observation is appropriate for asymptomatic patients with a minimal pneumothorax (<15-20% style="font-size: 0.85em; line-height: 0; ">27
• Supplemental oxygen: Oxygen administration at 3 L/min nasal canula or higher flow treats possible hypoxemia and is associated with a 4-fold increase in the rate of pleural air absorption compared with room air alone.
• Simple aspiration: In an earlier report, simple aspiration in 131 cases of small SP yielded successful results up to 87%.²⁸ Other data describe more limited success in up to 70% cases.²⁹ A more recent ED study supports needle aspiration as safe and effective as chest tube for PSP, conferring the additional benefits of shorter length of stay and fewer hospital admissions.³⁰
• Aspiration procedure description
  • Prepare the skin with Betadine solution and cover with sterile drapes.
  • Use a 1% Xylocaine solution for local anesthesia.
  • Select the puncture site at the second or third intercostal space in the midclavicular line or in the fourth or fifth intercostal space over the superior rib margin in the anterior axillary line.
  • Place a plastic catheter over the needle into the pleural space.
  • Use a 3-way stopcock and large syringe to evacuate air. When no more air can be aspirated or the patient suddenly coughs, the lung most likely has reexpanded.
  • Remove the catheter, and massage the insertion site with sterile gauze to seal the channel into the pleural space.
  • Obtain a follow-up chest radiograph.
• Chest tube for air removal: A tube inserted into the pleural space is connected to a device with one-way flow. Examples of such devices are Heimlich valves or water seal canisters, and tubes connected to wall suction devices.
  • Portable system (insertion of a one-way valve): The typical goal of one-way valve systems is to avoid hospital admission and still treat the SP. One-way valves may also expedite hospital discharge and be used during transport of an injured patient. A Heimlich valve allows for complete evacuation of air that is not under tension. Heimlich valves do not require suction and eliminate the chance of a tension pneumothorax; they allow greater mobility and less discomfort for the patient. By decreasing the length of the hospital stay and allowing for outpatient care, medical costs are reduced as well.
    
    In a pilot study, the efficacy and safety of a serial-steps approach with a single system (small-caliber catheter/Heimlich valve) were evaluated in 41 thin, young, smoking male patients with a first episode of PSP. A one-way Heimlich valve was connected to the catheter, allowing the air to flow spontaneously outward for 24-48 h. Thereafter, if the lung failed to re-expand, wall suction was applied. Patients with an air leak persisting for >4 days were referred for surgery. The 24-h and 1-wk success rates were 61% and 85%, respectively, and the actuarial 1-yr recurrence rate was 24%. When 24-h and 1-wk success rates and recurrence at 12 months were taken as end points, the method described here is as effective as simple manual needle aspiration or a conventional chest tube thoracotomy.³¹ 
    
    Heimlich valves are crucial in the care of patients with AIDS who have a median length of 20 days of chest tube placement.
• Thoracostomy with continuous (wall) suction: First-time SPS (including COPD) and traumatic pneumothorax typically require this approach. A small-bore catheter (eg, 7-14F) is safe to use in most patients, while a larger chest tube (24F) is also appropriate initially, and increasing suction pressure can be used if the lung fails to come up. A larger tube (eg, 28F) can reduce resistance in patients who are ventilated and at greater risk for air leaks. Air leaks resolve within 7 days of treatment 80% of the time, with an average hospital stay of 5 days. Keep the tube in place for 24 hours after the air leak ceases.

Prevention of recurrent pneumothorax 

• Observation: Observation is appropriate for iatrogenic pneumothorax in an individual with normal lungs who has responded to treatment with observation or simple aspiration. Simple aspiration or chest tube drainage of pneumothorax does not prevent recurrence. Recurrences have been reported to occur in up to 32% of PSP.^32,33 A recent study showed that a Heimlich valve with small-caliber catheter was less effective in preventing recurrence than closed thoracostomy. In another study, the recurrence rate after 1 year with Heimlich valve vs. chest tube placement was not significantly different.³⁴ Recurrent spontaneous pneumothorax requires more definitive treatment to prevent recurrence. Recurrence rates are higher with SSP than PSP; hence, observation is less often chosen as an approach in SSP.
• Pleurodesis: A patient treated with surgical pleurodesis has a recurrence prevention rate of greater than 90%. Talc is the preferred agent for pleurodesis. It can be administered by insufflation or as a slurry. Practice variation depends on local practitioner experience, resources, and success with approaches ranging from video-assisted thoracotomy (recommended by the American College of Chest Physicians)²⁰ to surgical thoracotomy and pleurectomy (recommended by the British Thoracic Society because of the absolute lowest recurrence rates).¹⁹
• Nonsurgical pleurodesis: "Medical" thoracoscopy requires only local anesthesia or conscious sedation, in an endoscopy suite, using nondisposable rigid instruments. Thus, it is considerably less invasive and less expensive, but also less effective, particularly in inexperienced hands. Patient comorbidity plays a role in selection of appropriate intervention. The main diagnostic and therapeutic indications for medical thoracoscopy are pleural effusions and pneumothorax.³⁵
  • Tetracycline and talc are well-studied effective agents for medical pleurodesis; the latter was 5% more effective in 1 randomized study.³⁶ Success rates for chemical are up to 91% vs. 95-100% in surgical techniques.³⁷ Chemical pleurodesis resulted in a significant reduction of recurrence compared to chest tube drainage alone in an early study.³⁸
  • Chemical pleurodesis and surgery were equally effective and were both superior to conservative therapy in preventing the recurrence of pneumothorax in LAM.

Surgical Care

• Indications for surgical assistance
  • Persistent air leak for more than 7 days
  • Recurrent ipsilateral pneumothorax
  • Contralateral pneumothorax
  • Bilateral pneumothorax
  • First-time presentation in a patient with a high-risk occupation (eg, diver, pilot)
  • Patients with AIDS often need this intervention because of extensive underlying necrosis.
  • The risk of recurrent pneumothorax may also be unacceptable for patients with plans for extended stays at remote sites.
  • Lymphangiomyomatosis, a condition causing a high risk of pneumothorax³⁹
• Video-assisted thoracoscopic surgery (VATS)
  • VATS is appropriate for recurrent primary spontaneous pneumothorax (PSP) or secondary spontaneous pneumothorax (SSP).
  • VATS with resection of large bullous lesions is associated with a recurrence rate of 2-14%.
  • VATS is done under general anesthesia using a camera and 2 trocar ports.
  • In a meta-analysis of 12 trials that randomized 670 patients, VATS was associated with shorter length of stay (reduction 1.0-4.2 d) and less pain or use of pain medication than thoracotomy in the 5 out of 7 trials in which the technique was used for pneumothorax or minor lung resection. In the treatment of pneumothorax, VATS was associated with substantially fewer recurrences than pleural drainage in 2 trials.⁴⁰
• Thoracotomy
  • Insufflation of talc and thoracotomy has a recurrence rate of 0-7%.
  • Recurrence rates are as low as 4%,³³ which may be higher than open procedure case series.
  • Talc is the preferred agent for pleurodesis. It can be administered by insufflation or as a slurry.
• Complications of surgical procedures include the following:
  • Failure to cure the problem
  • Acute respiratory distress or failure
  • Infection of the pleural space
  • Cutaneous or systemic infection
  • Persistent air leak
  • Reexpansion pulmonary edema
  • Prolonged tube drainage and hospital stay
  • Increased risk of post-operative bleeding after lung transplantation (for medical pleurodesis and surgery; not found to affect the length of hospital stay)³⁹

Consultations

• Consult with a surgeon about patients who require a chest tube, pleurodesis, or surgical thoracotomy and thoracoscopy.
• If patients have underlying lung disease, thereby increasing the chance of recurrence, consult a pulmonary specialist.
• Direct patients indicating a readiness to quit smoking to their primary care physician or offer referral for cessation management. This may include nicotine replacement and non-nicotine pharmacotherapy such as bupropion or varenicline.

Medication

The goals of pharmacotherapy are to reduce morbidity and to prevent complications. In addition to the medications listed below, talc may be used as a sclerosing agent for pleurodesis by mixing 2-5 g in 250 mL of sterile isotonic sodium chloride solution to form a slurry or poudrage. Acute respiratory distress syndrome (ARDS) has been reported after use of talc as a pleural sclerosing agent but is considered to be a rare complication.

Local anesthetics

Used for thoracentesis and chest tube placement.

Lidocaine hydrochloride (Xylocaine, Dilocaine, Anestacon)

Local anesthetic used as 1% solution. Onset of action is within 45-90 seconds. Duration of anesthesia is 10-20 min.
Adverse effects with use as local anesthetic include allergic reactions.

• Dosing
• Interactions
• Contraindications
• Precautions

Adult

Dose varies with the procedure, local vascularity, and condition of patient; applied locally, not to exceed 4.5 mg/kg; do not repeat within 2 h

Pediatric

Not established

Opiate analgetics

Used for pain control.

Fentanyl citrate (Sublimaze, Fentanyl Oralet)

Onset of analgesia is immediate with IV use. Duration of analgesia is 30-60 min. Respiratory depressant effect may last longer than analgesia.

• Dosing
• Interactions
• Contraindications
• Precautions

Adult

0.5-1 mcg/kg/dose IV for minor procedures; may repeat dose at 30- to 60-min intervals

Pediatric

Not established

Meperidine hydrochloride (Demerol)

Onset of analgesia occurs within 5 min. Titrate dose to effect. Half-life of the parent drug is 2.5-4 h, prolonged in patients with liver disease. Half-life of the active metabolite, normeperidine, is 15-30 h. Accumulates with high dose and renal insufficiency.

• Dosing
• Interactions
• Contraindications
• Precautions

Adult

50-150 mg/dose IV; can repeat in 3-4 h prn

Pediatric

Not established

Benzodiazepine

Used for conscious sedation.

Midazolam hydrochloride (Versed)

Benzodiazepine used for sedation component of conscious sedation protocol. Onset of action occurs within 1-5 min. Half-life of 1-4 h. Prolonged with liver cirrhosis, congestive heart failure, obesity, and old age.

• Dosing
• Interactions
• Contraindications
• Precautions

Adult

Initial dose: 0.5-2 mg IV over 2 min; slowly titrate to effect by repeating doses every 2-3 min; usual total dose is 5 mg; decrease initial dose in the older population to 0.5 mg IV; administer no more than 1.5 mg in a 2-min period, to a total dose of 3.5 mg

Pediatric

Not established

Follow-up

Further Outpatient Care

• Patients should receive follow-up care from a pulmonary physician within 7-10 days.

Deterrence/Prevention

• Patients should not travel by air or travel to remote sites until radiography shows complete resolution.
• Patients cannot smoke. They should be assessed as to readiness to quit, educated about smoking cessation, and provided with pharmacotherapy if ready to quit. Direct patients indicating a readiness to quit smoking to their primary care physician or offer referral for cessation management. This may include nicotine replacement and non-nicotine pharmacotherapy such as bupropion or varenicline.

Complications

• Respiratory or cardiac arrest
• Hemopneumothorax
• Bronchopulmonary fistula
• Pain at the site of chest tube insertion, infection, and hemorrhage

Prognosis

• Complete resolution of uncomplicated pneumothorax takes approximately 10 days.
• The recurrence rate of primary spontaneous pneumothorax (PSP) is 32%. The presence of emphysematouslike changes in PSP has no predictive value for the future development of recurrence.
• Age is a predictor of recurrence.
• Contralateral recurrence of PSP: A retrospective study of 231 patients with PSP showed that 33 (14%) had a contralateral recurrence.⁸ Low BMI was deemed a risk factor for contralateral recurrence on univariate and multiple logistic regression analysis. Contralateral blebs were seen by CT in higher frequency in the patients with contralateral recurrence than those without a contralateral recurrence. In this series, all patients with contralateral recurrence were treated surgically.⁸

Patient Education

• Smoking cessation

Miscellaneous

Medicolegal Pitfalls

• Imaging studies should not delay the diagnosis of tension pneumothorax. Tension pneumothorax is a medical emergency and requires immediate treatment.
• Chest radiographs may fail to reveal pneumothorax. Radiologists or emergency physicians may fail to recognize the presence of the pneumothorax. A vertical skin line can be mistaken for a pneumothorax, leading to unnecessary and possibly harmful therapy.
• Expiratory chest radiographs do not improve detection of pneumothorax after procedures with the potential to cause a pneumothorax.
• A high index of suspicion for tension pneumothorax is recommended in patients on mechanical ventilation with acute onset of hemodynamic instability, difficult ventilation with high inspiratory pressures, and worsening hypoxemia and/or hypercapnia, even with a functioning chest tube in place. Portable chest radiograph may fail to show the pneumothorax; CT may be required for diagnosis.
• Always consider pneumothorax in the differential diagnosis of major trauma.
• Spontaneous pneumothorax is a life-threatening condition in patients with severe underlying lung disease.
• CT scan of the chest is the most reliable imaging study for the diagnosis of pneumothorax.

Author: Rebecca Bascom, MD, MPH, Professor of Medicine, Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Pennsylvania State College of Medicine, Milton S Hershey Medical Center; Graduate Faculty Member, Pennsylvania State University College of Medicine and The Huck Institutes of the Life Sciences
Coauthor(s): Michael G Benninghoff, MS, DO, Fellow in Pulmonary and Critical Care Medicine, Penn State Hershey Medical Center;Shoaib Alam, MD, Assistant Professor of Medicine, Division of Pulmonary, Allergy and Critical Care, Pennsylvania State University and Hershey Medical Center