Pleural Disease: Tension Pneumothorax

Related Conditions

pulseless electrical activity

cardiopulmonary arrest

hypotension

hypoxia

1. Description of the problem

Tension pneumothorax is a life-threatening condition that causes both hypoxemia and shock. It needs to be treated emergently by decompressing the increased intrathoracic pressure.

There are no other effective interventions to save a patient who is dying from tension pneumothorax.

Tension pneumothorax will typically present with decreased or absent breath sounds on the affected side. The trachea may be deviated to the opposite side. The patient will typically be tachycardic and hypotensive. Pulse oximetry will usually be decreased.

1) If tension pneumothorax is suspected, then determine the side. History of a recent central line attempt may be relevant. If a patient is stable, an emergent chest radiograph can be obtained, but treatment of a patient in extremis in whom a tension pneumothorax is suspected should not be delayed for a radiograph.

2) If emergent – decompress the affected hemithorax on an emergent basis with either a needle or intravenous catheter

3) once decompression is complete establish a more stable palliative intervention with a chest tube

4) address the underlying cause

2. Emergency Management

If the patient is in distress and tension physiology is suspected, needle/catheter thoracostomy should be performed. In the setting of a PEA cardiopulmonary arrest, tension pneumothorax is on the differential diagnosis list and should be treated presumptively if the patient is resistant to other resuscitative measures. In this situation, a decompressive maneuver should be performed as a life-saving intervention in the absence of radiographic confirmation; as a delay for x-ray confirmation may result in the patient’s death as CPR is unlikely to maintain adequate perfusion in the setting of tension physiology.

How to perform needle/catheter thoracostomy:

– Place patient in the supine position and cleanse sterilely the superior, anterior chest.

– Feel the sternum to find the sterno-manubrial junction (“Angle of Louis”). Trace this angle laterally to identify the sternal insertion of the second rib.

– Follow the second rib laterally to the midclavicular line.

– At this point insert an intravenous catheter (16 gauge is ideal, but 14 or 18 can be used – or even a needle if that is all that is available) through the skin where you would envision the cephalad margin of the second rib [The cephalad margin of the rib is selected to avoid the intercostal bundles, which run along the caudal margin.]

– Advance the catheter slowly, but deliberately, into the chest. The trajectory of the catheter should be more or less perpendicular to the chest and should glance off the cephalad surface of the rib.

– If the needle or catheter has been mounted on a syringe for additional control, then the operator should maintain negative pressure on the plunger to assure that air is immediately identified when the pleural space is entered.

– Either way, the operator should brace the controlling hand on the patient to avoid plunging into the chest and injuring the lung or heart. That is, the operator should be controlling the catheter in a way that his or her hand moves with the patient if the patient moves. This is particularly important in these situations as this procedure may be required during a code situation with a patient undergoing CPR.

– If an intravenous catheter is being used, then the needle should be advanced another two or three millimeters to assure the plastic catheter tip is in the chest, not just the needle tip. Once air is encountered, the catheter is then advanced over the needle and into the chest.

– If the patient has a tension pneumothorax, then a hissing sound will be heard as the pressurized air escapes and, invariably, the patient’s cardiopulmonary status will improve.

– Once the catheter is in place, then a standard chest tube should be placed. Whereas any physician should be willing and able to decompress a tension pneumothorax, it is perfectly reasonable to call for surgical assistance to place a chest tube if the decompressing physician is uncomfortable with that procedure.

– In a situation such as this a 28 Fr chest tube placed in the anterior axillary line, at the fifth or sixth interspace and directed anteriorly to drain air, should be a safe tube.

Management points not to be missed

– Use the history and physical exam to determine the site of the suspected tension pneumothorax, if a chest x-ray has not been performed or time does not permit.

– Make sure to enter over the top surface of the rib.

– Immediately make preparations for placement of a proper chest tube after the chest has been decompressed.

3. Diagnosis

The diagnosis is usually easily established with a chest x-ray, but a physical examination with decreased breath sounds and, possibly, contralateral tracheal deviation is highly suggestive in a clinical setting suggestive of tension pneumothorax. In the supine ICU patient, particularly with underlying lung pathology, the diagnosis may be missed radiologically for 2 major reasons:

(1) If ithe pulmonary process has resulted in non-compliant lungs or adjacent pleural inflammation, the lung may not fully deflate.

(2) Pleural air may accumulate anteriorly, in the supine patient, and compress the lung below it without seeing a pleural line laterally. In the latter case, a unilateral hyperlucent area may be the only radiographic manifestation or a deep sulcus sign.

No lab values are of use in the diagnosis of tension pneumothorax. A chest x-ray will be diagnostic and will show collapse of the lung with contralateral deviation of the mediastinum.

The clinician will know a patient has tension pneumothorax if the patient has progressive, unexplained hypotension, tachycardia, hypoxia and/or tachypnea in the setting of a physical examination with unilateral decreased breath sounds, distended neck veins and/or contralateral tracheal deviation.

The diagnosis should be at the top of the list for a decompensating patient who is on positive pressure ventilation, who recently underwent a central line placement/attempt or thoracentesis and was previously stable. It should also be very high on the differential list if the patient has a known history of previous pneumothoraces or if a patient is on high inspiratory pressure ventilatory support and demonstrates a sudden decompensation.

If a patient arrests from tension pneumothorax, it may well manifest as pulseless electrical activity. If a catheter or chest tube has been placed in both chest cavities and a hissing sound is not heard with immediate clinical improvement, then other causes of PEA should be considered:

Hypokalemia
Hypovolemia
Hypoglycemia
Hypoxia
Hypothermia
Tamponade
Thromboembolism
Toxins

Confirmatory tests

A chest x-ray should not delay treatment of a dying patient, but in a less acute situation, will establish the diagnosis. A chest x-ray should always be obtained after a chest tube has been placed. This is performed to confirm the location of the tube, confirm reexpansion of the lung and to determine if reexpansion pulmonary edema has occurred.

4. Specific Treatment

Refractory cases

If decompressing a tension pneumothorax does not help, then the clinician needs to focus on other potential causes for the patient’s decompensation.

It is possible in an obese patient, or with an inexperienced or tentative operator, that the pleural space has not been entered. If the patient has a tension pneumothorax, then there is no other option but to cannulate the pleural space and relieve the gas under pressure. In the former situation a longer catheter, such a spinal needle, can be used or an incision can be made in the chest to allow the available needle or catheter to reach the inside of the chest.

In the case of an inexperienced or tentative clinician, the operator must simply accomplish the task and boldly advance the needle or catheter until the confirmatory hissing sound of escaping air is heard.

The tentative operator can take comfort from the knowledge that if the patient is in such a state that there is no opportunity to wait for a more experienced clinician, then there is no other choice and they would be exonerated from any complications they might envision by virtue of attempting to perform the only maneuver that could save the patient’s life.

5. Disease monitoring, follow-up and disposition

Expected response to treatment

Typically, a patient will have an immediate and dramatic recovery when a tension pneumothorax is relieved. If the patient does not rebound, then there has been collateral damage to other organs, likely the heart or brain, that occurred while the patient was in extremis or arrested.

A delayed complication can be reexpansion pulmonary edema, which should be treated like any other type of pulmonary edema if the lung is already fully expanded.

Other complications which may affect prognosis would be injuries related to placement of the decompressing catheter or the subsequent chest tube. If the pneumothorax has been intercepted with alacrity, then the prognosis related to the pneumothorax should be excellent, depending upon the patient’s comorbidities. Finally, if the pneumothorax has occurred in the setting of a patient on mechanical ventilation, then a persistent air leak is a potential complication.

Once the lung is fully expanded, then the airway pressures should be minimized and the chest tube should be placed on waterseal, or the minimal suction necessary to maintain lung inflation and avoid subcutaneous emphysema, in order to avoid potentiating the air leak.

Incorrect diagnosis

If the operator does not hear the hiss of escaping air upon entering the chest and/or there is not immediate improvement in the patient’s cardiopulmonary status upon entering the chest, then it would appear likely that there has either been a misdiagnosis or another critical condition is coexistent at that point.

Follow-up

If thoracic surgery was not involved in the placement of the chest tube, then they should be consulted to help follow and manage the patient. If the pneumothorax arose in the setting of an underlying lung disease (secondary spontaneous pneumothorax) then the pulmonary medicine service should also be consulted.

Pathophysiology

The pathophysiology of tension pneumothorax is that air escapes from a hole in the lung where a functional one way valve-type opening exists. The air will collect in the pleural space, ultimately under pressure. Symptoms may initially present, depending upon the patient’s pulmonary reserve, from collapse of the one lung. Ultimately, however, as the pressure exceeds that of venous inflow into the thorax the patient will suffer cardiac compromise as well.

Epidemiology

Although there is a typical phenotype of the tall, slender young male who is prone to primary spontaneous pneumothorax, it can present in anyone. Tension PTX should be at the top of the differential list for any deteriorating patient who has recently undergone a central line attempt, thoracentesis, lung biopsy or any other procedure where a needle may have contacted the lung. Any mechanically ventilated ICU patient with primary pulmonary pathology, with either restrictive or obstructive physiology, has an increased risk for pneumothorax and tension pneumothorax.

The increased transpulmonary pressures associated with mechanical ventilation increases the risk of alveolar rupture due to regional hyperinflation (with obstruction) or due to direct tissue destruction in the setting of pneumonitis or acute lung injury (with restriction).

It is important to remember that the apices of the lungs extend into the base of the neck and base of the lungs extend very caudally along the back. It is imperative that the clinician keep this diagnosis in mind in the ICU setting when a patient is on a ventilator and, perhaps, noncommunicative.

Prognosis

The prognosis for a quickly recognized and treated tension pneumothorax, in an otherwise healthy patient, is excellent. This occurrence will likely serve as an indication for surgical treatment of a primary spontaneous pneumothorax.

In a healthy patient where the pneumothorax is not quickly decompressed, then the prognosis will be related to the secondary damage from hypoxia and/or cardiac compromise. If this occurs in a sick patient, then the prognosis will be greatly affected by the patient’s comorbidities.

Special considerations for nursing and allied health professionals.

It is critical that ICU nurses are familiar with this condition as they are most likely to witness the patient’s initial decompensation and have the ability to call for assistance and raise the possibility of a pneumothorax, especially if a patient is on a ventilator. Once a chest tube is in place, they must be facile in the management of the tube and whatever drainage device has been attached to it.

Beyond assuring the tubing is not kinked, they must know how to recognize if the suction is functioning and also whether there has been any change in the character of the leak as indicated in the waterseal chamber.

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