Pneumothorax

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Pneumothorax

  1. 1. Pneumothorax- a pneumothorax is a potential medical emergency wherein air or gas is present in the pleural cavity. Type of pneumothorax: o o o 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. o Traumatic pneumothorax results from injury, typically blunt or penetrating trauma. o Tension pneumothorax develops when air is trapped in the pleural cavity under positive pressure. EtiologyIt most commonly arises: -Spontaneously (more commonly in tall slim young males and in Marfan syndrome)
  2. 2. -Following a penetrating chest wound -Following barotrauma to the lungs. It may also be due to: -Chronic lung pathologies including emphysema, asthma -Acute infections -Chronic infections, such as tuberculosis -Lung damage caused by cystic fibrosis -Lung Cancer Rare diseases that are unique to women such as Catamenial pneumothorax (due to endometriosis in the chest cavity) and lymphangioleiomyomatosis (LAM). Pneumothoraces are divided into tension and non-tension pneumathoraces. A tension pneumothorax is a medical emergency as air accumulates in the pleural space with each breath. The increase in intrathoracic pressure results in massive shifts of the mediastinum away from the affected lung compressing intrathoracic vessels. A non-tension pneumothorax by contrast is of lesser concern because there is no ongoing accumulation of air and hence no increasing pressure on the organs within the chest.
  3. 3. The accumulation of blood in the thoracic cavity (hemothorax) exacerbates the problem, creating a hemopneumothorax. PathophysiologyThe 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. Blebs and bullae (sometimes called emphysematous-like changes or ELCs) are related to the occurrence of primary spontaneous pneumothorax.
  4. 4. 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.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.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.
  5. 5. 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. 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 include tuberculosis, 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
  6. 6. 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. 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
  7. 7. reducing cardiac output. In addition, owing to ipsilateral lung collapse and contralateral lung compression, gas exchange is compromised, leading to hypoxemia. Clinical History -Acute onset of chest pain - Severe and/or stabbing pain, radiating to ipsilateral shoulder and increasing with inspiration (pleuritic) -Sudden shortness of breath, dry coughs, cyanosis (turning blue) -Anxiety, 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. -In penetrating chest wounds, the sound of air flowing through the puncture hole may indicate pneumothorax, hence the term "sucking" chest wound. The flopping sound of a punctured lung is also occasionally heard. Subcutaneous emphysema is another symptom.
  8. 8. -If untreated, hypoxia may lead to hypercapnia, respiratory acidosis, and loss of consciousness. In a tension pneumothorax, shifting of the mediastinum away from the site of the injury can obstruct the superior and inferior vena cava resulting in reduced venous return. This in turn decreases cardiac preload and cardiac output. Physical 1.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
  9. 9. -Hyperresonance on percussion -Decreased tactile fremitus 2.Cardiovascular - Jugular venous distension (tension pneumothorax) 3.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 1.Risks factors for primary spontaneous pneumothorax (PSP) -Smoking -Marfan syndrome -Pregnancy
  10. 10. -Familial pneumothorax -A primary spontaneous pneumothorax may occur without either trauma to the chest or any kind of blast injury. This type of pneumothorax is caused when a bleb (an imperfection in the lining of the lung) bursts causing the lung to deflate. The lung is reinflated by the surgical insertion of a chest tube. A minority of patients will suffer a second instance. In this case, thoracic surgeons often recommend thorascopic pleurodesis to improve the contact between the lung and the pleura. If multiple and/or bilateral occurrences continue, surgeons may opt for a far more invasive bullectomy and pleurectomy to permanently adhere the lung to the interior of the rib cage with scar tissue, making collapse of that lung physically impossible. Primary spontaneous pneumothorax is most common in tall, thin men between 17 and 40 years of age, without any history of lung disease. Though less common, it also occurs in women, usually of the same age and body type. The tendency for primary spontaneous pneumothorax sufferers to be tall and thin is not due to weight, diet or lifestyle, but because the genetic predisposition toward those traits often coincides with a genetic predisposition toward high volume lungs with large, burstable blebs. A small portion of primary spontaneous pneumothoraxes occur in persons outside the typical range of age and body type
  11. 11. 2.Diseases and conditions associated with secondary spontaneous pneumothorax Chronic obstructive pulmonary disease (COPD), Asthma. HIV/AIDS with Pneumocystis jiroveci (PCP) infection. Necrotizing pneumonia, Tuberculosis, Cystic fibrosis (CF) Bronchogenic carcinoma, Metastatic malignancy Inhalational and intravenous drug use such as marijuana and cocaine has been implicated as etiology of SP as well. Interstitial lung diseases associated with connective tissue diseases(Ankylosing spondylitis) Idiopathic pulmonary fibrosis, Sarcoidosis Lymphangioleiomyomatosis (LAM), histiocytosis Langerhans cell Acute respiratory distress syndrome (ARDS) and positive pressure ventilation in ICU Severe acute respiratory syndrome (SARS) , endometriosis Thoracic 3.Causes of iatrogenic pneumothorax Transthoracic needle aspiration biopsy of pulmonary nodules, Transbronchial biopsy .
  12. 12. Thoracentesis, Tracheostomy Central venous catheter insertion, Intercostal nerve block Cardiopulmonary resuscitation Positive pressure ventilation and ARDS in the ICU Nasogastric feeding tube placement, Acupuncture 4.Causes of traumatic pneumothorax Trauma - Penetrating and nonpenetrating injury Rib fracture High-risk occupation (eg, diving, flying) Differential diagnosis Esophageal Spasm Pericarditis, Acute Pleurodynia Pulmonary Embolism Acute Myocardial Infarction: presents with shortness of breath and chest pain, though MI chest pain is characteristically crushing, central and radiating to the jaw, left arm or stomach. Whilst not a lung condition, patients having an MI often happen to also have lung disease.
  13. 13. Emphysema: here, delicate functional lung tissue is lost and replaced with air spaces, giving shortness of breath, and decreased air entry and increased resonance on examination. However, it is usually a chronic condition, and signs are diffuse (not localised as in pneumothorax). Diagnosis 1.The absence of audible breath sounds through a stethoscope can indicate that the lung is not unfolded in the pleural cavity. This accompanied by hyperresonance (higher pitched sounds than normal) to percussion of the chest wall is suggestive of the diagnosis. The "coin test" may be positive. Two coins when tapped on the affected side, produce a tinkling resonant sound which is audible on auscultation. 2. If the signs and symptoms are doubtful, an X-ray of the chest can be performed, but in severe hypoxia, or evidence of tension pneumothorax emergency treatment has to be administered first. An x-ray can illustrate the collapse of the lung as extra black space, indicating the presence of air, will be seen in the xray around the lung. The lung shrivels up away from the affected side and the mediastinum (trachea and other components) will shift towards the unaffected side. In a supine chest X-ray the deep sulcus sign is diagnostic, which is characterized by a low lateral costophrenic angle on the affected side. In layman's terms, the place where rib and
  14. 14. diaphragm meet appears lower on an X-ray with a deep sulcus sign and suggests the diagnosis of pneumothorax. 3. 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. 4. 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. One study showed absent lung sliding from an anterior approach indicated pneumothorax. Management
  15. 15. Chest wound- Penetrating wounds (also known as 'sucking chest wounds') require immediate coverage with an occlusive dressing, field dressing, or pressure bandage made air-tight with petroleum jelly or clean plastic sheeting. The sterile inside of a plastic bandage packaging is good for this purpose; however in an emergency situation any airtight material, even the cellophane of a cigarette pack, can be used. A small opening, known as a flutter valve, may be left open so the air can escape while the lung reinflates. Any patient with a penetrating chest wound must be closely watched at all times and may develop a tension pneumothorax or other immediately life-threatening respiratory emergency at any moment. They cannot be left alone. Blast injury or tension- If the air in the pleural cavity is due to a tear in the lung tissue (in the case of a blast injury or tension pneumothorax), it needs to be released. A thin needle can be used for this purpose, to relieve the pressure and allow the lung to reinflate. Pre-hospital care- Many paramedics can perform needle thoracocentesis to relieve intrathoracic pressure. Intubation may be required, even of a conscious patient, if the situation deteriorates. Advanced medical care and immediate evacuation are strongly indicated.
  16. 16. An untreated pneumothorax is an absolute contraindication of evacuation or transportation by flight. Small pneumothoraces- Small pneumothoraces are often managed conservatively as they will resolve on their own. Repeat observation via chest X-rays and oxygen administered. Pneumothoraces which are too small to require tube thoracostomy and too large to leave untreated, may be aspirated with a small catheter. Larger pneumothoraces- Large pneumothoraces may require tube thoracostomy, also known as chest tube placement. If a thorough anesthetizing of the parietal pleura and the intercostal muscles is performed, the only major pain experienced should be either the injury that caused the pneumothorax or the re-expanding of the lung. Proper anesthetizing will come about by the following procedure: the needle should be inserted into the chest cavity and a negative pressure created in the syringe. While air bubbles rise into the syringe, the needle should be slowly pulled out of the cavity until the bubbles cease. The tip of the syringe that contains the anesthetic is now in the intercostal muscles just next to the parietal pleura. A proper and sizable injection should ensue (5 to 10 ml). This will allow the patient to be fairly comfortable despite a hemostat or finger being inserted into the chest cavity. A tube is then inserted through the chest wall into the
  17. 17. pleural space and air is extracted using a simple one way valve or vacuum and a water valve device. This allows the lung to reexpand within the chest cavity. The rate of re-expansion will vary widely. It is important not to connect the chest tube to suction right away, as rapid expansion may lead to pulmonary edema. The pneumothorax is followed up with repeated X-rays. If the pneumothorax has resolved and there is no further air leak, the chest tube is removed. If, during the time that the tube is still in the chest, the lung manages to sustain the reexpansion, but once suction is turned off, the lung collapses, a Heimlich valve may be used. This flutter valve allows air and fluid in the pleural cavity to escape the pleura into a drainage bag while not letting any air or fluid back in. This method was developed by the military in order to get soldiers with lung injuries stable and out of the battlefield faster. It is a rarely used medical device in the treatment of patients these days, but may be used in order to allow the patient to leave the hospital. It is critical that the chest tube be managed in such a way that it does not become kinked or occluded with clot or other fibrinous material. Chest tube clogging can result in build up of air in the pleural space. At the very least, this will lead to a recurrent pneumothorax. In the worse case, the patient can have a tension pneumothorax if the air builds up under pressure and impairs venous return to the heart. This can be
  18. 18. fatal. The tubes have a tendency to form clot from blood and other fibrinous material that can occlude them. To keep them open they must be stripped, milked or even replaced if they totally occlude. Smaller tubes are less traumatic, but more prone to clogging, although this can also occur with larger tubes. One sign the chest tube is clogged is subcutaneous emphysema. Another is a loss of respiratory variation in the fluid level at the water seal valve in the drainage canister. In the situation that the chest tube is not sufficient in healing of the lung (for example, a continued air leak despite chest tube drainage), or if CT scans show the presence of large "bullae" on the surface of the lung, thoracoscopic surgery, or video assisted thorascopic surgery (VATS), may be done in order to staple the leak shut and to irritate the pleura to promote adhesions between the lung and pleura (pleurodesis). Two or three small incisions are made in the side of the chest and back, one for a small camera and the other (s) for tools used to seal the lung and abrade or remove the pleura. When finished the wound is covered with a steri-strip and bandaged up. In case of penetrating wounds, these require attention, but generally only after the airway has been secured and a chest drain inserted. Supportive therapy may include mechanical ventilation. Surgical Care
  19. 19. Indications for surgical assistance: 1.Persistent air leak for more than 7 days. 2.Recurrent ipsilateral pneumothorax. 3.Contralateral pneumothorax. 4.Bilateral pneumothorax. 5.First-time presentation in a patient with a high-risk occupation (eg, diver, pilot). 6.Patients with AIDS often need this intervention because of extensive underlying necrosis. 7.The risk of recurrent pneumothorax may also be unacceptable for patients with plans for extended stays at remote sites. 8.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. Thoracotomy Insufflation of talc and thoracotomy has a recurrence rate of 07%.
  20. 20. Talc is the preferred agent for pleurodesis. It can be administered by insufflation or as a slurry. Complications of surgical procedures include the following: 1.Failure to cure the problem. 2.Acute respiratory distress or failure. 3.Infection of the pleural space, 4.Cutaneous or systemic infection 5.Persistent air leak 6.Reexpansion pulmonary edema 7.Prolonged tube drainage and hospital stay 8.Increased risk of post-operative bleeding after lung transplantation (for medical pleurodesis and surgery; not found to affect the length of hospital stay) 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. 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. 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.
  21. 21. 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) to surgical thoracotomy and pleurectomy (recommended by the British Thoracic Society because of the absolute lowest recurrence rates). 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. -Tetracycline and talc are well-studied effective agents for medical pleurodesis; the latter was 5% more effective in 1 randomized study. Success rates for chemical are up to 91% vs. 95-100% in surgical techniques. Chemical pleurodesis resulted in a significant reduction of recurrence compared to chest tube drainage alone in an early study.
  22. 22. -Chemical pleurodesis and surgery were equally effective and were both superior to conservative therapy in preventing the recurrence of pneumothorax in LAM. 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. 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. Adverse effects with use as local anesthetic include allergic reactions. Opiate analgetics- Used for pain control.
  23. 23. Fentanyl citrate (Sublimaze, Fentanyl Oralet)- Onset of analgesia is immediate with IV use. Duration of analgesia is 3060 min. Respiratory depressant effect may last longer than analgesia. 0.5-1 mcg/kg/dose IV for minor procedures; may repeat dose at 30- to 60-min intervals. 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. 50-150 mg/dose IV; can repeat in 3-4 h prn 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. 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. Complications -Respiratory or cardiac arrest
  24. 24. -Hemopneumothorax -Bronchopulmonary fistula -Pain at the site of chest tube insertion, infection, and hemorrhage

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