Surgery for Chronic Obstructive Pulmonary Disorder
Jerry Robinson, a retired 52-year-old postal worker, goes to his local hospital’s emergency department for shortness of breath. Mr. Robinson states that while lifting boxes in his garage, he suddenly felt an intense pain over his right chest and began breathing heavily. He says he has never had this type of pain before in his life, and he describes it as worsening with deep breathing. His medical history is significant only for hypertension and a cholecystectomy. He admits to having smoked two packs of cigarettes a day since age 20 years, but he has not smoked a single cigarette during the past 18 months. He denies any chest pain, coughing, or hemoptysis before this episode. He has been short of breath on mild exertion (dyspnea scale, 2.75) for a number of years, and he has used bronchodilators occasionally for what he calls a wheezing problem. The patient has no drug allergies, and his medication includes a calcium channel blocker for high blood pressure.
What is the most likely diagnosis in Mr. Robinson’s case?
The most likely diagnosis with this history is spontaneous pneumothorax. The differential diagnosis at this point includes pulmonary embolus, acute bronchospasm, myocardial infarction, and less probably, dissecting aortic aneurysm.
On physical examination, Mr. Robinson is agitated, diaphoretic, and tachypneic. He is conscious, well oriented, and not cyanotic. His vital signs are as follows: heart rate, 112 beats per minute, regular sinus; blood pressure, 168/94 mm Hg; respiratory rate, 24 breaths per minute; temperature, 37.3°C; and oxygen saturation, 90% on room air. His jugulars are not distended, his heart sounds are normal, and chest auscultation reveals decreased breath sounds diffusely, no wheezing, and increased resonance on percussion over his right chest. Examination of his abdomen and lower extremities is unremarkable.
What should be included in Mr. Robinson’s initial workup?
The workup on admission should consist of a complete blood count, electrolytes, blood urea nitrogen and creatinine levels, cardiac enzymes, a chest radiograph, and an electrocardiogram (ECG).
Mr. Robinson’s blood work, cardiac enzymes, and ECG are within normal limits. The chest radiograph shows a 3-cm pneumothorax starting at the apex of his chest cavity and extending down to his diaphragm. There is no cardiomegaly, and the left lung appears to be normal.
How should the patient be managed at this point?
The chest radiograph confirms the diagnosis suggested by the history and physical examination. A 3-cm pneumothorax in a symptomatic patient necessitates drainage. Supplemental oxygen should be administered to maintain an oxygen saturation above 92%, and a peripheral intravenous line should be started. Information about Mr. Robinson’s arterial blood gases is not useful at this point because it does not add any pertinent information and only delays the necessary procedure.
What type of pneumothorax is presented in this case?
This is a secondary spontaneous pneumothorax because it occurs in a patient who probably has an underlying pulmonary disorder: chronic obstructive pulmonary disease (COPD). Primary spontaneous (or idiopathic) pneumothoraces occur in young, healthy persons with no underlying pulmonary disease. The general classification of pneumothoraces is given in Table 27.1.
TABLE 27.1. Classification of Pneumothoraces
What clinical features are associated with a primary spontaneous pneumothorax?
Primary spontaneous pneumothoraces occur with an incidence of 6 to 7 per 100,000 men and 1 to 2 per 100,000 women in North America (1). The rupture of a small subpleural bleb within the visceral pleura allows air to escape into the pleural cavity, where it accumulates and collapses the lung. These pneumothoraces are most prevalent in young adults; 85% of patients are younger than 40 years of age. Typically, the patient is a tall, slim 20- to 25-year-old man with a smoking history. Without definite therapy, the recurrence rate is high, estimated at 25% after a first episode, 40% to 50% after a second episode, and more than 60% after a third episode (2,3).
What is the pathophysiology of subpleural blebs?
The formation of subpleural blebs results from the rupture of apical alveoli. The gradient between the intrabronchial and intrapleural pressures is greater at the lung apices, creating more tension on the walls of the apical alveoli, which leads to their overexpansion and eventual rupture. Once the alveolus ruptures, gas escapes and dissects peripherally along the lobular septa and collects as blebs beneath the visceral pleura. These blebs are generally found at the lung apex, in the superior segment of the lower lobes, and along the fissures. By definition, they are smaller than 2 cm in diameter.
What alterations of pulmonary physiology are caused by pneumothoraces?
How are secondary spontaneous pneumothoraces defined?
Secondary spontaneous pneumothoraces accompany underlying pulmonary disease. They account for only 20% of spontaneous pneumothoraces overall (80% are primary or idiopathic) and most often are associated with COPD. The mean age of patients is older than 50 years, and as pulmonary functions are compromised, they are more commonly symptomatic (4).
What other diseases are associated with secondary spontaneous pneumothoraces?
Other pulmonary disorders include cystic fibrosis, bullous disease, interstitial diseases (e.g., idiopathic pulmonary fibrosis, sarcoidosis, eosinophilic granuloma), and infectious processes (e.g., pneumonia, tuberculosis, abscesses). Neoplasms, whether primary or metastatic, also may cause a pneumothorax, but this is rare.
Mr. Robinson is seen by the general surgeon on call that day in the emergency department. After reviewing the history, physical examination, and chest radiograph findings, the surgeon proceeds with a tube thoracostomy of the right chest.
What size chest tube should be inserted and where?
The size of a chest tube depends on what type of substance is being drained from the pleural cavity. Generally, a size 20-French chest tube is sufficient for pneumothorax. When draining blood, pus, or thick fluid, a large-bore tube (size 28 to 36 French) is recommended. The chest tube for a pneumothorax is inserted in the fifth intercostal space on the midaxillary or anterior axillary line, and it is directed toward the apex of the pleural cavity. A chest tube for an apical pneumothorax also may be inserted through the anterior chest wall in the second intercostal space on the midclavicular line. A pleural effusion is drained with a chest tube in the fifth or sixth intercostal space directed posteriorly and inferiorly (5).
Once inserted, should the chest tube have suction?
Suction on a chest tube is used to ensure optimal drainage of the pleural cavity. Suction is required for pneumothorax when chest radiograph does not show the lung to be completely expanded after tube thoracostomy or if there is a large air leak. Once the lung is completely expanded, suction should be reduced to a minimum or stopped to help seal the air leak.
The chest radiograph taken after Mr. Robinson’s chest tube is inserted shows adequate tube placement and a small residual 8-mm pneumothorax at the apex of the right lung field. A moderate-sized air leak from the tube is also shown. The chest tube is placed under water seal drainage, and 20 cm of negative pressure is applied. The patient is admitted to the hospital, and a daily chest radiograph is ordered.
Is chest tube drainage required for all patients with a pneumothorax, and if not, what are the criteria for conservative management?
All patients with a symptomatic pneumothorax need drainage. Some patients who meet specific criteria may be treated with observation alone. These criteria include no symptoms, a pneumothorax less than 20% or 2 cm, and a young and reliable patient (i.e., primary spontaneous pneumothorax). Patients with secondary pneumothorax have much less pulmonary reserve and thus are at higher risk for complications or even death if the pneumothorax progresses rapidly. Conservative management is possible in 15% to 20% of patients overall (2,6).
When pneumothorax is treated conservatively, how long does resolution take?
The rate of resorption of air from the pleural cavity is estimated to be 1.25% of the volume of the pneumothorax per 24 hours (50 to 70 mL per day) or the equivalent of 1 mm a day. A 2-cm pneumothorax takes up to 3 weeks to resolve completely.
What types of drainage procedures are available?
A spontaneous pneumothorax may be drained by simple needle aspiration using a 16- to 18-gauge needle catheter and a three-way stopcock. However, this procedure is associated with a 50% to 70% failure rate and thus is rarely used (4). Drainage of the pleural space may be obtained with any of a variety of small-caliber catheters (10 to 16 French) to which suction usually can be applied. Although less traumatic on insertion and more comfortable for the patients, these small-bore tubes easily become clogged with fibrin and blood clots. Conventional tube drainage with a 20- to 24-French chest tube remains the gold standard because it is safe, effective, and reproducible and is associated with an 80% to 90% success rate in the management of spontaneous pneumothorax (7).
What is a Heimlich valve, and when is its use indicated?
The Heimlich valve is a one-way flutter valve that is connected to the end of a chest tube, eliminating the need for an underwater seal drainage bottle or suction. The valve is designed to let air out of the pleural cavity in the presence of an air leak (8). The valve is ideally suited for outpatient management of uncomplicated spontaneous pneumothorax and for persistent air leaks. It is recommended only for patients whose lungs are fully reexpanded and for reliable patients with adequate pulmonary function. Regular chest radiographs and follow-up are necessary. The chest tube is removed once the air leak has resolved.
What complications are associated with spontaneous pneumothoraces?
Complications include pleural effusion (15%), persistent air leak (10%), tension pneumothorax (5%), hemothorax (3%), pneumomediastinum (2%), and empyema (less than 1%).
How does a hemothorax secondary to a pneumothorax occur?
When a pneumothorax occurs suddenly, adhesions between the parietal and visceral pleura may tear as the lung collapses. These adhesions may contain blood vessels, so when they are torn, bleeding results. Avulsion of a subclavian vein also has been reported in association with a spontaneous pneumothorax. When the hemorrhage is massive or continuous, an exploratory thoracotomy is indicated.
Mr. Robinson’s air leak persists for 5 days and eventually seals spontaneously. The chest radiograph shows a well-expanded lung. The chest tube is removed uneventfully, and the patient is discharged from the hospital. Then, 2 weeks after returning home, Mr. Robinson once again develops acute-onset shortness of breath with right-sided chest pain. He is rushed to the hospital, where an emergency department chest radiograph shows complete collapse of his right lung secondary to a pneumothorax. A chest tube is rapidly inserted by the thoracic surgery resident on call. The patient’s shortness of breath markedly improves shortly after the chest tube is placed. Mr. Robinson is admitted to the hospital, and his chest tube is set on 20 cm of suction.
How should Mr. Robinson’s problem now be managed?
The patient’s spontaneous pneumothorax is managed the same as the first episode. At this point, surgical therapy must be considered.
What are the indications for surgery in patients with primary and secondary spontaneous pneumothoraces?
Second episode of ipsilateral pneumothorax
Previous contralateral pneumothorax
Air leak persisting longer than 7 to 10 days
Massive air leak preventing adequate lung expansion
Bilateral simultaneous pneumothorax
Complications of a pneumothorax (e.g., hemothorax, empyema)
Indications specific to the underlying pulmonary disorder
Is this patient’s occupation an important consideration?
Some occupations carry an inherent risk of pneumothorax. Airline pilots and scuba divers are managed more aggressively, and surgery is considered after a first episode. Patients who live far from medical centers also are managed surgically after an initial episode of spontaneous pneumothorax (4).
What are the objectives of surgical therapy?
The foremost objective of surgery for spontaneous pneumothorax is preventing recurrences. Other objectives include ensuring complete expansion of the lung, treating complications, and managing bronchopleural fistulas.
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