WORKUP

Imaging Studies:

• Chest radiograph for the evaluation of pneumothorax

• Although expiratory images are thought to better depicting subtle pneumothoraces (the volume of the pneumothorax is constant and hence proportionally higher on expiratory images), a recent randomized controlled trial revealed no difference in the ability of radiologists to detect pneumothoraces on inspiratory and expiratory images.

• In patients with underlying pulmonary disease, the classic visceral pleural line may be harder to detect, because the lung is hyperlucent, and little difference exists in the radiographic density between the pneumothorax and the emphysematous lung.

• Ratio of lung size to hemothorax size to estimate pneumothorax size

   

  • The size of a pneumothorax may be estimated by using the ratio of the lung diameter cubed to the hemithorax diameter cubed.

     

  • This formula assumes a constant shape of the lung when it collapses and is invalid if pleural adhesions are present.

     

  • The clinical status of the patient (not the size of the pneumothorax) should be emphasized when making therapeutic decisions.

• A supine chest radiograph may depict the deep sulcus sign (very wide and deep costophrenic angle). The anterior costophrenic recess becomes the highest point in the hemithorax, resulting in an unusually sharp definition of the anterior diaphragmatic surface or an increased lucency in the ipsilateral upper quadrant of the abdomen.

• Chest radiography for the evaluation of pneumomediastinum

• Mediastinal emphysema appears as a thin line of radiolucency that outlines the cardiac silhouette, as well as thin, lucent, vertically oriented streaks of air within the mediastinum.

• The aorta and other posterior mediastinal structures are highlighted, and a well-defined lucency around the right pulmonary artery (ring around the artery sign) may be seen.

• Air most easily is detected retrosternally on the lateral chest radiograph. An anteroposterior chest radiograph may not depict the finding in 50% of cases.

• Unlike air in a pneumothorax or pneumopericardium, the air remains fixed in pneumomediastinum and does not rise to the highest point.

• Contrast-enhanced esophagogram: If emesis or retching is the precipitating event, an esophagogram should be obtained to evaluate Boerhaave syndrome (an esophageal tear), which has a high mortality rate.

Procedures:

• Tube thoracostomy

• If the patient is hemodynamically stable, consider conscious sedation with careful titration of a short-acting narcotic and benzodiazepine.

   

• Place the patient in a 30-60° reverse Trendelenburg position. Scrub the site (centered around the fifth or sixth rib in the midaxillary line) with Betadine and/or alcohol.

• Locally anesthetize site with lidocaine. (Use a generous amount, and anesthetize all the way down to the pleura.)

• Make a 3- to 4-cm incision.

• Use a curved hemostat, puncture (in a controlled manner) through the intercostal muscles and parietal pleura immediately superior to the rib border, avoiding damage to the underlying lung. Spread the hemostat wide to create an adequate opening.

• Perform a digital examination to assess the presence and location of pulmonary adhesions. Sweep the finger in all directions, and feel for the diaphragm and possible intra-abdominal structures. To avoid losing the desired tract, some recommend keeping the finger in place until tube is inserted.

• Insert the chest tube along the finger; use a clamp on the tube, if desired.

• Direct the chest tube posteriorly, and insert it until it is at least 5 cm beyond the last hole in the tube.

• Attach the tube to a water seal and vacuum device (eg, Pleur-Evac). Look for respiratory variation of the water seal and bubbling of air through the water seal. Document the amount of blood or other fluids drained.

• Suture the site, and secure the tube to the chest wall. Cover the site with Vaseline-impregnated gauze, and apply a suitable dressing. A variety of anchoring and closure techniques exist, all of which are probably equivalent.

• Obtain a chest radiograph to confirm placement and lung re-expansion.

• Needle aspiration

• Palpate the rib and intercostal space intended for needle aspiration. For air aspiration, the anterior approach at the second or third intercostal space at the midclavicular line or a lateral approach at the fifth or sixth intercostal space at the midaxillary line is appropriate. Instill local anesthetic as deep as to the pleura, directing the needle over the top of the rib into the desired intercostal space.

• Insert a 16-gauge Angiocath or ready-to-use aspiration kit into the fourth or fifth intercostal space at the anterior axillary line.

• Remove the needle once the pleural cavity is entered, and attach the catheter to 3-way stopcock and 60 mL syringe.

• Withdraw air continually until no more can be aspirated (discontinue if resistance is felt, if the patient coughs excessively, or if more than 2.5 L is aspirated). Close the stopcock and secure the catheter to the chest wall.

• Obtain a chest radiograph to assess the degree of success, and obtain another radiograph 4 hours later to confirm the absence of recurring accumulation.

• If no recurrence is present, remove the catheter, and discharge the patient with appropriate return instructions. (Some authors suggest observation for an additional 2 h after catheter removal.)

• If the pneumothorax persists, attach a Heimlich valve or a water seal and admit the patient.

• Pleurodesis (See Further Inpatient Care).

TREATMENT

Prehospital Care:

• Assess the ABCs, and evaluate the possibility of a tension pneumothorax. Assess the vital signs, and perform pulse oximetry. A tension pneumothorax is almost always associated with hypotension.

• Administer oxygen to the patient, and establish an intravenous line.

• Most paramedics are trained to perform needle decompression for immediate relief of a tension pneumothorax.

Emergency Department Care: Immediate attention to the ABCs while assessing vital signs and oxygen saturation is paramount. ED care depends on the hemodynamic stability of the patient. All patients should receive supplemental oxygen to increase oxygen saturation and to enhance the reabsorption of free air. Treatments for primary and secondary spontaneous pneumothorax are the following:

• Primary spontaneous pneumothorax

• If the pneumothorax is smaller than 15% and if the patient is symptomatic but hemodynamically stable, aspiration is the treatment of choice.

• If the pneumothorax is smaller than 15% and if the patient is asymptomatic, observation is considered by many to be the treatment of choice. (If the patient is admitted, administer oxygen, since this has been shown to speed resolution of the pneumothorax.)

• Secondary spontaneous pneumothorax

• Tube thoracostomy is the procedure of choice.

• Pleurodesis decreases the risk of recurrence.

• Aspiration is the technique of choice for iatrogenic pneumothoraces because recurrence usually is not a factor.

• Most patients with pneumomediastinum should be admitted and observed for signs of serious complications (eg, pneumothorax, tension pneumothorax, mediastinitis). If the pneumomediastinum occurred from the inhalation of cocaine or smoking of marijuana, observation in the ED for progression may be indicated.

Consultations: Physicians from various services may be needed to care for patients who require tube thoracostomy and admission. A surgeon and a pulmonologist should evaluate patients with multiple recurrent diseases to determine the cause and further management.

MEDICATION

The goals of pharmacologic therapy are to reduce symptoms and prevent potential complications.

Drug Category: Anesthetic -- Anesthetic agents are used for analgesia in the treatment of sclerotic lesions.

Drug Name	Lidocaine (Dilocaine) -- Decreases the permeability to sodium ions in neuronal membranes, resulting in the inhibition of depolarization, and blocking the transmission of nerve impulses. The application of 5% gel is effective in the treatment of painful lesions.
Adult Dose	2-3 mg/kg intrapleurally
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; Adams-Stokes syndrome and Wolf-Parkinson-White syndrome; severe sinoatrial, AV, or intraventricular block if no artificial pacemaker is present
Interactions	Coadministration with cimetidine or beta-blockers increases toxicity of lidocaine; coadministration with procainamide and tocainide may result in additive cardiodepressant action; may increase effects of succinylcholine
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Use a solution without preservatives; caution in heart failure, hepatic disease, hypoxia, hypovolemia or shock, respiratory-depression, and bradycardia; may increase risk of CNS and cardiac adverse effects in elderly patients; high plasma concentrations can cause seizures, heart block, and AV conduction abnormalities

Drug Category: Benzodiazepine -- Useful for premedication prior to sclerosis and placement of a thoracostomy tube.

Drug Name	Lorazepam (Ativan) -- Sedative hypnotic with short onset of effects and relatively long half-life. Increases the action of GABA, a major inhibitory neurotransmitter in the brain. May depress all levels of the CNS, including the limbic and reticular formations.
Adult Dose	Initial dose: 2 mg total or 0.044 mg/kg IV, whichever is smaller Alternative: 0.05 mg/kg IV; not to exceed 4 mg/dose
Pediatric Dose	0.05-0.1 mg/kg IV slowly over 2-5 min; may repeat 0.5 mg/kg IV slowly
Contraindications	Documented hypersensitivity; preexisting CNS depression, hypotension, narrow-angle glaucoma
Interactions	Toxicity of benzodiazepines in CNS increases when used concurrently with alcohol, phenothiazines, barbiturates, and MAOIs
Pregnancy	D - Unsafe in pregnancy
Precautions	Caution in renal or hepatic impairment, myasthenia gravis, organic brain syndrome, Parkinson disease

Drug Category: Analgesic -- Pain control is essential to good patient care. It ensures patient comfort and promotes pulmonary toilet. Most analgesics have sedating properties, which are beneficial for patients with painful skin lesions. Analgesics are important in the initial placement of thoracostomy tubes and for controlling pain after the procedure.

Drug Name	Morphine (Duramorph, MS Contin, Oramorph) -- DOC for analgesia because of reliable and predictable effects, safety profile, and ease of reversibility with naloxone.
Adult Dose	Initial dose: 0.1 mg/kg IV/IM/SC Maintenance dose: 5-20 mg/70 kg q4h IV/IM/SC; IV doses vary; titrate for desired effect
Pediatric Dose	Neonates: 0.05-0.2 mg/kg IV/IM/SC prn Children: 0.1-0.2 mg/kg IV/IM/SC q2-4h prn IV doses vary; titrate for desired effect
Contraindications	Documented hypersensitivity; hypotension; potentially compromised airway with uncertain rapid airway control; respiratory depression; nausea; emesis; constipation; urinary retention
Interactions	Phenothiazines may antagonize analgesic effects of opiate agonists; tricyclic antidepressants, MAOIs, and other CNS depressants may potentiate adverse effects
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution in atrial flutter and other supraventricular tachycardias; vagolytic action may increase ventricular response rate

FOLLOW-UP

Further Inpatient Care:

• Prophylactic antibiotics: Although no data support the use of prophylactic antibiotics, many physicians routinely treat patients with antibiotics until the chest tube is removed.

• Analgesics: Patients may require analgesics for comfort until the thoracostomy tube is removed. Some authors advocate the use of intercostal nerve blocks to increase patient comfort and decrease the need for analgesics.

• Suction: Strong suction should not be used with a spontaneous pneumothorax because of the increased risk of re-expansion pulmonary edema.

• Video-assisted thoracoscopic surgery

• This procedure is replacing thoracotomy in the treatment of chronic or persisting pneumothoraces.

• Indications include an unexpanded lung 5 days after tube thoracostomy, bronchopleural fistula persisting for 5 days or longer, recurrent pneumothorax after chemical pleurodesis, and occupational reasons (eg, airplane pilots, deep-sea divers).

• Pleurodesis: This treatment decreases chance of pneumothorax recurrence. It should be performed just after reinflation of the lung if the presence of an air leak is not a contraindication. The 2 major sclerosing agents are talc and tetracycline derivatives (eg, minocycline, doxycycline). This procedure should be performed in consultation with the surgeon.

• Talc (5-10 g in 250 mL sterile isotonic sodium chloride solution) usually is insufflated during video-assisted thoracoscopic surgery or thoracotomy, but 1 study of 32 patients demonstrated findings of successful treatment with a chest tube (10% recurrence at 5 y). Because of reports of acute respiratory distress syndrome resulting from talc treatment in malignant pleural effusions, some authors recommend use of the tetracycline derivatives as the first agent of choice.

• In a large Department of Veterans Affairs study, tetracycline pleurodesis had a 25% recurrence in patients compared with 41% in control subjects. However, tetracycline no longer is available for pleurodesis because of stringent manufacturing requirements. Minocycline and doxycycline have been shown to be successful sclerosing agents. Bleomycin was found to be ineffective in rabbits and is expensive.

   

• Sclerosis is painful, and the patient should be premedicated with benzodiazepine and intrapleural lidocaine.

• Follow-up for pneumomediastinum

   

  • A follow-up chest radiograph should be obtained in 12-24 h to detect any progression or complication, such as pneumothorax.

     

  • If no progression occurs at 24 hours and if no evidence of mediastinitis exists, the patient may be discharged.

Further Outpatient Care:

• Heimlich valve placement

• The Heimlich valve is a one-way, rubber flutter valve. The proximal end attaches to the chest tube, and the distal end connects to a suction device or is left open to the atmosphere.

• It allows outpatient treatment of a pneumothorax.

• It has been used in some patients with AIDS, although opponents argue against exposing the public to secretions.

Deterrence/Prevention:

• Smoking is a strong risk factor for spontaneous pneumothorax. Compared with nonsmokers, men have a 20-fold increased risk of spontaneous pneumothorax (>80-fold increase for men who smoke more than 1 pack per day), and women have a 10-fold increased risk (>40-fold increase for women who smoke more than 1 pack per day).

Complications:

• Re-expansion pulmonary edema

• This condition is a unilateral pulmonary edema that rarely occurs after re-inflation of a collapsed lung

• Incidence, etiology, risks, and mortality rates are controversial.

• Findings from animal studies and several case reports in humans indicate that re-expansion pulmonary edema may occur more often if a pneumothorax is present longer than 3 days and if suction is applied. This information is important because in 1 study, 46% of patients waited more than 2 days after their symptoms started to seek medical attention, and in another study 18% waited more than 7 days.

• For spontaneous pneumothoraces, suction should not be applied because of an often-delayed presentation and, thus, an increased risk of re-expansion pulmonary edema. In addition, 1 study revealed that the rate of lung re-expansion is independent of suction.

• Re-expansion pulmonary edema can occur in the opposite lung.

• Tension pneumothorax

• Accidental disconnection and malpositioning of Heimlich valves

Prognosis:

• The prognosis is generally good with appropriate therapy.

PICTURES

Caption: Picture 1. This is a chest radiograph of an elderly male with chronic obstructive pulmonary disease who presented with a second left-sided spontaneous pneumothorax in 2 months. Chest thoracostomy was performed, the patient was admitted, and talc pleurodesis was performed the next day.
Picture Type: X-RAY

Caption: Picture 2. This chest radiograph shows pneumomediastinum (radiolucency noted around the left heart border) in this patient who had a respiratory and circulatory arrest in the ED after experiencing multiple episodes of vomiting and a rigid abdomen. The patient was taken immediately to the operating room, where a large rupture of the esophagus was repaired.
Picture Type: X-RAY