Chapter 38. Needle Thoracostomy

A tension pneumothorax is a unilateral progressive collection of air in the pleural space. If not treated, it results in increasing intrapleural pressures, shifting of intrathoracic structures, hypoxemia, and death. It occurs from a one-way air leak into the pleural cavity from the airway conduits, the lung, or the thoracic wall. The air leak causes air to enter the pleural cavity and become trapped, without a method of egress. Rapid decompression of the tension pneumothorax with a catheter-over-the-needle is known as a needle thoracostomy and can be lifesaving.

A tension pneumothorax is an immediate life-threatening condition that requires prompt recognition and treatment to prevent the patient's imminent demise. The diagnosis must be suspected based upon the patient's prior medical history, the mechanism of injury, physical examination findings, and a patient in extremis. Importantly, treatment must not be delayed to obtain further diagnostic testing (e.g., chest radiograph). These patients most often present with acute and dramatic cardiopulmonary compromise, which may be manifest by a combination of the following signs and symptoms: respiratory distress, chest pain, air hunger, hypotension, tachycardia, diaphoresis, unilateral absence of or decrease in breath sounds, hyperresonance to percussion, increased central venous pressure, hypoxemia, cyanosis, deviation of the cardiac point of maximal impulse, and tracheal deviation.

The most common cause of a tension pneumothorax is mechanical ventilation with positive pressure in a patient with a visceral pleural injury.1 A tension pneumothorax is present in 50% of ventilator-associated pneumothoraces.2 When this occurs in intensive care unit (ICU) patients, they often have minimal functional reserve. To further cloud the issue, they are frequently on other supports (i.e., inotropic agents, complex ventilator settings, etc.), making their physical examination difficult and confusing. They may also have a number of other coexisting factors that are making them unstable. This group of patients has a particularly disastrous course if a tension pneumothorax develops. Rapid diagnosis and treatment are imperative.3

The placement of a central venous catheter has been associated with the development of a pneumothorax. The incidence of this is approximately 3% to 6% with use of the subclavian approach. A tension pneumothorax may be delayed in approximately 0.4% of attempts to gain central venous access. In one case report, a patient developed a tension pneumothorax while under general anesthesia 10 days after the placement of a subclavian central venous line.4

A tension pneumothorax may also occur in the setting of blunt or penetrating trauma of the lung. It may occur uncommonly following a tracheobronchial or esophageal injury. It may complicate a simple pneumothorax if the parenchymal lung leak does not seal spontaneously. In this case, the site of the lung injury acts as a one-way valve, allowing air entry into the pleural space and not allowing it to escape. Occasionally, chest wall defects may result in a tension pneumothorax if the wound is completely covered by an occlusive dressing or if the wound itself acts as a ball-valve mechanism. More rarely, it may occur following markedly displaced fractures of the thoracic spine. In the past, based on studies using the canine model, the pathophysiology of this disease was considered to be associated primarily with a mechanical pressure-related phenomenon.5 Air accumulated in the involved pleural space and caused an increasing intrapleural pressure. This pressure caused compression of the ipsilateral lung, displacement of the diaphragm caudally, movement of the mediastinum and heart toward the uninjured side, kinking of the great vessels, and compression of the contralateral lung. This anatomic shift of structures would result in impaired filling of the heart and a disastrous fall in cardiac output.6 Unfortunately, the canine model is not as similar to the human as was once thought. The mediastinum in the dog is more mobile. It is fenestrated, so that air communicates from one hemithorax to the other. Therefore, elevations of intrapleural pressure in dogs would affect central structures and cause cardiovascular compromise more readily than in humans.

Recently, this pressure-related mechanism has come into question as the primary event. Experiments have been performed in goats, monkeys, sheep, and swine; all of which have a mediastinum that is more similar to that of the human than the dog.7–10 These studies support the hypothesis that central hypoxemia is the primary factor in the lethality of a tension pneumothorax and occurs prior to the development of significant hypotension. In this hypothesis, the mechanical pressure-related phenomenon is a late event.

These mechanisms become more confusing and mixed in the ventilator-dependent patient. There is a lack of studies documenting hemodynamic changes in the human subject with a tension pneumothorax.11–14 In one case report, three ventilated ICU patients demonstrated decreased cardiac output as the first sign of a tension pneumothorax.12 The authors proposed that the absence of spontaneous breathing did not allow increased variations in negative intrathoracic pressure to act as a compensatory mechanism to prevent hemodynamic compromise. In another similar case, decreased cardiac output and mixed venous oxygen saturation were the dominant signs of a tension pneumothorax.13 Hemoglobin desaturation via pulse oximetry was shown to be the earliest sign in a ventilator-dependent patient with a tension pneumothorax.14

Electrocardiographic (ECG) changes may be seen in association with a tension pneumothorax. In a left-sided tension pneumothorax, the more commonly described ECG changes are a rightward shift of the mean frontal QRS axis, precordial T-wave inversions, reduced R-wave voltage, and decreased and/or alternating QRS amplitude.15–17 Other unique changes include PR-segment elevation in the inferior leads and reciprocal PR-segment depression in lead aVR.18 A case report cited transient bradycardia, hypotension, and precordial ST-segment elevation; all of which reversed after treatment of a right-sided tension pneumothorax.19

Numerous mechanisms have been proposed as the causes of these ECG changes. They include simple displacement of the heart, rotation of the heart around its anteroposterior or longitudinal axis, transient hypoxia, changes in coronary artery blood flow, changes in pleural pressure, pulmonary resistance, pericardial tension, acute ventricular dilatation, alterations in ventricular repolarization, pressure-induced atrial injury, and insulation of the chest wall from the associated air.15–20 The vast majority of ECG changes have been noted with left-sided rather than right-sided tension pneumothoraces. The degree of pneumothorax and the severity of symptoms do not seem to correlate with the magnitude of the ECG abnormalities. In summary, ECG changes are not uncommon in tension pneumothorax and should not distract from the true diagnosis.

A tension pneumothorax must be considered in the differential diagnosis of any patient in extremis. If it is a possible etiology for the patient's cardiopulmonary collapse, needle decompression should be performed without delay. In every circumstance, and especially in the emergent setting, one may not be able to be 100% certain of the diagnosis. However, needle decompression is a relatively low-risk procedure with great lifesaving potential.

One setting that may be particularly confusing is in the dying patient with left precordial penetrating trauma. The immediate differential would be tension pneumothorax versus pericardial tamponade versus massive hemothorax. Physical examination findings are usually helpful but may also be confusing, mixed, or difficult to elicit in a chaotic and noisy resuscitation. Needle decompression should be the first maneuver in this situation. It may be lifesaving and will aid in the diagnosis. It is less invasive, quicker, and easier to perform than a pericardiocentesis or a thoracotomy. A tension pneumothorax is more common than pericardial tamponade in this setting. As for a massive hemothorax, a chest tube setup requires some time but should be requested at the time needle decompression is proceeding.

There are no absolute contraindications to performing a needle thoracostomy to decompress a tension pneumothorax. It is imperative to identify the anatomic landmarks properly and perform this procedure carefully if the patient has a known or suspected coagulopathy.

• Povidone iodine or chlorhexidine solution
• 12 to 16 gauge catheter-over-the-needle, 4.5 cm in length
• 5 or 10 mL syringe
• Sterile gloves and gown
• Face mask with an eye shield or goggles
• Ultrasound machine (optional)
• Low frequency (2-5 MHz) ultrasound probe
• Sterile ultrasound probe cover
• Sterile ultrasound gel

Briefly describe the procedure to the patient if they are competent, able to understand, and cooperative. Place the patient supine. Some Emergency Physicians place the patient supine with the head of the bed elevated to 30°. This will allow the air to rise to the anterior upper chest. Unfortunately, this is not the most functional position. It is from the supine position that the patient can most easily be accessed and controlled by the greatest number of practitioners. The supine position is optimal to allow for other lifesaving maneuvers (e.g., airway management, cardiopulmonary resuscitation, etc.). Clean the skin of any dirt and debris in the area of the procedure. Apply povidone iodine or chlorhexidine to the skin.

Simultaneous with the performance of this procedure, other interventions should be requested: 100% face-mask oxygen (if the patient is not already intubated), pulse oximetry, cardiac monitoring, chest tube setup, intravenous access, and STAT chest radiography. The Emergency Physician should wear full personal protective equipment to protect themselves from contact with the patient's blood and body fluids. While time is of the essence and this is an emergent procedure, aseptic technique should be followed.

The safest, easiest, and most reliable site for a needle thoracostomy to decompress a tension pneumothorax is the second intercostal space in the midclavicular line1,2,6,21 (Figure 38-1). Apply a 12, 14, or 16 gauge catheter-over-the-needle onto a 5 or 10 mL syringe without the plunger. Identify the second intercostal space in the midclavicular line. Place the nondominant index finger over the needle insertion site. Grasp the syringe with the dominant hand. Insert the catheter-over-the-needle perpendicular to the skin and just above the superior border of the third rib (Figure 38-2A). This will avoid injury to the neurovascular bundle underlying the inferior border of the second rib. Some Emergency Physicians prefer to contact the upper portion of the third rib with the tip of the needle, walk it up the rib until it goes over the edge, and then advance it into the pleural space.

Advance the catheter-over-the-needle until a loss of resistance is felt as the tip of the needle penetrates the pleural space. A rush of air, with or without blood, will be heard escaping from the syringe. Stop advancing the catheter-over-the-needle. Advance the catheter until the hub is against the skin while simultaneously withdrawing the needle (Figure 38-2B).

Other sites have been described for performing a needle thoracostomy. These include the fourth or fifth intercostal space in the midaxillary line or the second intercostal space in the anterior axillary line.22–25 There are several problems with these alternative sites. In the fourth or fifth intercostal space, the ribs are close together, with narrower interspaces making needle placement more difficult. There is more rib motion with breathing and arm movement can make catheter dislodgment more likely. In the supine patient, air will rise ventrally rather than laterally. Practically speaking, during the resuscitation of the unstable patient, the most important position for the Emergency Physician is at the patient's head. Insertion of a catheter in the second intercostal space in the midclavicular line is easier from this position than inserting a laterally placed catheter. The fourth or fifth intercostal space in the midaxillary line is the ideal space for a chest tube. Placement of the catheter in these alternative sites would mean having to penetrate more tissue, especially in the obese patient, making reaching the pleural space more difficult, and dislodgment of the catheter more likely. The major drawback to using the fourth or fifth intercostal space is the risk of inserting the catheter-over-the-needle below the diaphragm and into the liver (on the right) or the spleen (on the left).

If the first attempt at needle thoracostomy fails to decompress the pleural space, ultrasound can be used to measure chest wall thickness in order to determine the appropriate needle length and to confirm the presence or absence of a pneumothorax. Subcutaneous fat and tissue can be differentiated from air in the pleural space by the presence of the pleura seen deep to the pneumothorax and represented by a bright white line along with the absence of “lung slide.”

If the patient is in extremis, a definitive chest tube should not be the primary therapy for a tension pneumothorax. The setup and performance of a tube thoracostomy take much longer than rapid decompression with a catheter-over-the-needle.

Hanging Drop Test

A novel idea has been proposed to use the “hanging drop” test to identify the pleural space and determine if a tension pneumothorax is present.26 It is quick, easy to perform, and uses supplies readily available in the Emergency Department. Be aware that gathering the supplies and performing this test can take a few minutes, thus delaying the needle decompression.

Using strict aseptic technique, insert a 4.5 cm long spinal needle into the second intercostal space in the midclavicular line and advance it until the tip is touching the upper border of the third rib. Remove the trocar. Place one to two drops of sterile saline or sterile water into the hub of the spinal needle. The fluid bubble will be elevated above the needle hub. Gently walk the needle up and over the edge of the third rib. Slowly advance the needle through the intercostal tissues while observing the fluid bubble. The negative intrathoracic pressure will suck the fluid bubble into the chest of there is no tension pneumothorax. The fluid bubble will be pushed out of the hub if a tension pneumothorax is present.

The author suggests using a spinal-type needle.26 This cannot be recommended for two reasons. First, if a tension pneumothorax is present, the sharp needle should not be advanced or left in the pleural cavity to relieve a tension pneumothorax. It can puncture an organ or blood vessel. Second, the spinal needle would have to be removed and the procedure repeated with a catheter-over-the-needle. Consider using a catheter-over-the-needle to perform this procedure to avoid these issues.

The basic technique is the same in pediatric patients. Use a smaller length and gauge catheter-over-the-needle in pediatric patients. A 20 or 22 gauge, 1 inch (in) or 2.5 cm catheter-over-the-needle should be used in preterm children and neonates. This same size can also be used in children up to approximately 1 to 2 years of age. Between the approximate ages of 2 and 6 years, consider using an 18 or 20 gauge, 1.5 in or 3.75 cm long catheter-over-the-needle. Over the age of 6 and into early adolescence, consider using a 16 or 18 gauge, 4.5 cm long catheter-over-the-needle. Use the adult size catheter-over-the-needle for older adolescents or obese children. These are just general recommendations. The individual child's size and body habitus need to be taken into consideration when choosing a catheter-over-the-needle size and length.

Some Physicians prefer to use a butterfly needle with attached tubing instead of a catheter-over-the-needle in preterm children, neonates, and up to the first year of life. Select a butterfly needle size as described above. Place sterile water or sterile saline in a sterile specimen cup. Insert the distal hub end of the butterfly tubing into the bottom of the specimen container and submerged in the liquid. Tape the tubing onto the rim of the specimen container to secure it and ensure it does not pull out of the liquid in the specimen container. Insert the butterfly needle into the pleural space as described above. Air bubbles will move through the tubing and into the sterile liquid as the tension pneumothorax is decompressed. The specimen container also forms a water seal, preventing ingress of air into the pleural space, until a tube thoracostomy can be performed.

Once the catheter has been placed into the pleural space, a gush of air should rush out of the syringe. The procedure will have converted a tension pneumothorax into a simple pneumothorax requiring a tube thoracostomy. The patient should improve hemodynamically and symptomatically. Saturations on pulse oximetry should rise after the decompression. If this does not occur, too short of a catheter-over-the-needle may have been used and the procedure should be repeated with a longer one. If a longer catheter-over-the-needle is not available, rapidly perform a tube thoracostomy. The other possibility is that the pleural space was entered appropriately but the diagnosis was incorrect. In this event, another cause of the patient's shock state should be sought and consideration should be given to “prophylactic” chest tube placement. This may prevent later sequelae from the iatrogenic catheter stab wound to the chest and simplify the further workup and monitoring of this unstable patient.

After insertion of the catheter and improvement in the patient's clinical status, the immediate life threat has been treated. Secure the catheter against the skin with a suture or an assistant holding it in place. Continue to observe and monitor the patient closely for recurrence of the tension pneumothorax and procedural complications. Establish intravenous access, cardiac monitoring, and pulse oximetry if not already done. Obtain baseline laboratory studies, an arterial blood gas, and a chest radiograph. Obtain a thorough history and physical examination to search for the etiology of the tension pneumothorax. A definitive chest tube should be placed using sterile technique to prevent recurrence of the tension pneumothorax and to treat the simple pneumothorax. Refer to Chapter 39 for the complete details regarding the placement of a chest tube. After a chest tube is inserted, remove the needle thoracostomy catheter and place a simple bandage over the puncture site.

An incorrect diagnosis of a tension pneumothorax in an unstable patient is always a possibility, even in the best of hands. If this is the case, the cause of the patient's shock state must still be aggressively sought and treated. A prophylactic chest tube should be considered for a presumed parenchymal lung injury and potential pneumothorax from the needle thoracostomy.27–29 This is especially true if the patient is going to be transported out of the resuscitation area, will be given a general anesthetic, or is to be placed on positive-pressure ventilation.

Failure to reach and decompress the pleural space is the major argument against the use of needle thoracostomy. Depending on the patient's body habitus and the catheter length, the pleural space may not have been reached to be decompressed. In an initial study from the UK, the chest wall thickness was estimated to range from 1.3 to 5.2 cm by ultrasound in the second intercostal space.30 A 3.0 cm cannula would fail to penetrate into the pleural cavity in 57% of the patients in this study. A 4.5 cm cannula would fail to penetrate into the pleural cavity in 4% of the patients. In this case, the procedure should be repeated with a longer catheter-over-the-needle. If one is not immediately available, a tube thoracostomy should be performed immediately.

Several studies have evaluated chest wall thickness using ultrasound and computed tomography (CT) scans in order to determine the needle length required to appropriately decompress the pleural space in the general adult population. Initial studies using ultrasound seemed to indicate that using needle lengths of 4.5 cm would be sufficient to reach the pleural space in most patients.30 More recent studies using CT have shown that chest wall thickness varies significantly by gender and age. A study by Zengerink et al. found that chest wall thickness was greater than 4.5 cm 10% of the time in men younger than 40 and 19% of the time in men older than 40 years of age.31 The same study found almost one-third of women less than 40 years had a chest wall thickness greater than 4.5 cm, falling to one-fourth for those over 40. Harcke et al. found a mean chest wall thickness of 5.36 cm in autopsy CT scan studies.34 They recommended a 3.25 in or 8 cm long catheter-over-the-needle be used. It is important to note these variations. However, most authors still advocate a needle length of 4.5 cm as longer needle lengths increase the risk of vascular, pulmonary, or cardiac injury.

The second intercostal space in the midclavicular line is the recommended location for a needle thoracostomy. A prospective study of needle thoracostomy sites found that a more medial placement was often used.35 A needle thoracostomy insertion point not in the midclavicular line is more likely to be associated with vascular injury and hemorrhage. This includes injury to the internal mammary artery medially, subclavian vessels superiorly, and the pulmonary trunk and heart inferiorly.

After the initial effective decompression of a tension pneumothorax, the catheter may become dislodged, clotted, kinked, or its tip may retract from the pleural space into the surrounding soft tissues. If the tension pneumothorax recurs, immediately repeat the procedure. Once needle decompression is reaccomplished, immediately perform a tube thoracostomy. If possible, a tube thoracostomy can be initiated by the Emergency Physician while other members of the resuscitation team continue with other interventions. This would hopefully prevent recurrence of the tension pneumothorax secondary to a delay in chest tube placement because other interventions (e.g., CPR, intubation, venous access, etc.) must also be performed.

There may be complications secondary to the catheter placement.37–40 A local hematoma or underlying lung laceration may occur. Infectious agents may be introduced into the pleural cavity. If the catheter-over-the-needle is introduced too close to the sternum, the underlying mediastinal vessels or internal mammary artery may be penetrated or lacerated. If the catheter-over-the-needle is introduced under the inferior border of the second rib instead of over the superior border of the third rib, the intercostal vessels or nerve may be lacerated. A proper technique in placing the catheter-over-the-needle should be observed to minimize preventable complications.

The standard approach to relieving a tension pneumothorax is the placement of a large-bore needle in the ipsilateral second intercostal space. This works well in the standard patient where there are no adhesions or scarring in the pleural space. However, this may not be the proper needle location in the patient with prior pulmonary disease, pleural disease, or pleural adhesions. The classic hospital patient in this category is the patient with adult respiratory distress syndrome on positive end-expiratory pressure (PEEP) with high airway pressures who develops a loculated tension pneumothorax. The needle placed in the standard manner often fails to reach the affected pleural area. Stat chest radiographs are often required to help guide placement of the needles and/or chest tubes in these more complex patients.6 Bedside ultrasonography is also useful to help guide the procedure.

The needle thoracotomy procedure is not without its complications. This leads some to question the performance of a needle thoracostomy instead of just performing a tube thoracostomy. There are no clinical trials comparing needle versus tube thoracostomy to relieve a tension pneumothorax in human subjects. This study was recently undertaken in a swine model.36 The authors demonstrated that a properly performed needle thoracostomy is as effective over a 4-hour period as a tube thoracostomy. While the authors did not record the time it took to perform the procedures, performing a needle thoracostomy is quicker, easier, and simpler and now just as effective when compared to a tube thoracostomy.

Tension pneumothorax is a clinical diagnosis that is often made in an agonal patient with respiratory distress, absent (or decreased) breath sounds over a hemithorax, and severe cardiopulmonary compromise. Needle thoracostomy to decompress the tension pneumothorax should be performed immediately in the second intercostal space in the midclavicular line. This is a lifesaving procedure that is quick, simple to perform, easy to learn, and requires no special equipment. Needle thoracostomy should be followed as soon as feasible by a definitive tube thoracostomy.