Chapter 35
Barotrauma and Chest Tubes 
Rupture of alveoli typically occurs when peak airway pressures exceed 40 to 50 cm H2O. As peak airway pressures approach 70 cm H2O, the incidence may exceed 40%. When the interstitial-alveolar pressure gradient is exceeded, alveolar rupture results in air tracking along the peribronchial vascular sheath into the interstitium. This air can then propagate further, dissecting along any of the contiguous planes of the body and resulting in a variety of complications, from fairly benign to rapidly lethal (Box 35.1).
Manifestations of Barotrauma
Tension pneumothorax remains one of the most feared complications in the ICU. If left untreated, it can rapidly lead to hemodynamic and respiratory instability and potentially cardiorespiratory arrest. Classic signs and symptoms include absent breath sounds, jugular venous distention, and tracheal deviation; however, these are frequently unreliable and difficult to assess in the mechanically ventilated patient. Unexplained tachycardia and hypotension, increasing central venous pressures, as well as increasing peak airway and plateau pressures and diminishing tidal volumes are more reliable signals of a developing tension pneumothorax in the critically ill patient. Tube thoracostomy should be performed expeditiously if a tension pneumothorax is suspected. If the patient is in extremis or in cardiac arrest, immediate decompressive needle thoracostomy may be attempted. This involves placement of a long 14-gauge angiocatheter in the second intercostal space at the midclavicular line. However, it is important to recognize that clinical, cadaveric, and radiologic studies have demonstrated significant shortfalls with this technique. If needle thoracostomy at the second intercostal space fails to result in clinical improvement, then an immediate tube or needle thoracostomy should be performed in the midaxillary line at the fifth intercostal space. If needle thoracostomy is performed, this should be followed by proper tube thoracostomy as soon as the clinical situation allows.
Systemic gas embolization may occur when air tracks along the peribronchial vascular sheath and encounters either a vascular disruption or a severe parenchymal infiltrate that blocks further dissection of the air. Adverse effects of this phenomenon may include circulatory collapse, cerebral infarction, seizures, or myocardial injury. Treatment considerations should include aggressive cardiopulmonary resuscitation, hyperoxygenation, and maintenance of adequate vascular volume. In the case of neurologic symptoms caused by arterial air embolism, consideration should be given to systemic anticoagulation and hyperbaric oxygen treatment (Chapter 56). For large venous air embolisms, partial aspiration via a right atrial catheter may be attempted.
Chest Tube Selection, Insertion, and Management
Indications and Selection of Tubes
Pneumothorax is the most common indication for chest tube placement in the ICU. However, other indications may include effusion, hemothorax, or empyema (Box 35.2). In the emergent setting, a large bore tube is always preferable, particularly if the exact cause of the patient’s deterioration is unclear. However, in an elective setting, the current trend is to place smaller caliber tubes whenever possible in order to minimize patient discomfort and to promote effective pulmonary toilet.
Insertion Technique: Traditional Chest Tubes (20-40 Fr)
Chest tube insertion (tube thoracostomy) is not without risk and requires sufficient expertise in the procedural aspects as well as the management of potential complications associated with the procedure (Box 35.3). The procedure is most easily performed with the patient in the supine position and the ipsilateral arm abducted or resting over the patient’s head. Patients who are hemodynamically stable may receive preprocedural sedation. In awake patients, analgesia should always be administered. Although intercostal nerve blocks are possible, the easiest method to administer analgesia is by direct injection of local anesthetic solution around the region of planned entry. The key anatomic landmark is the fifth intercostal space at the midaxillary line, which corresponds to the nipple or inframammary fold. Once the chest wall is prepped and draped in the usual sterile fashion, local anesthetic is infiltrated into the area. An incision large enough to accommodate the tube and one finger is made in the skin and carried down through the subcutaneous tissue. An extrathoracic tract is then developed using a large Peon or Kelly clamp down to the sixth rib. Additional local anesthetic is injected into the intercostal muscles and pleural space. The clamp is then used to gently spread the intercostal muscles above the sixth rib and then pass over the rib into the pleural space. Following a large spread of the clamp, a finger is inserted into the pleural space and a careful exploration should be performed to confirm intrathoracic position and free any pleural adhesions. Using the finger still in the chest, a chest tube is inserted with a clamp and guided in the cranioposterior direction. The tube is advanced gently until slight resistance is met and then secured in place with heavy suture. Of note, the numbers on the side of most chest tubes represent the distance in centimeters from the last “sentinel” hole, not from the end of the chest tube itself. A chest radiograph should be obtained for confirmation of position and to identify the location of the sentinel hole of the chest tube (signified by a break in the radio-opaque line on the chest tube). Malpositioned chest tubes require replacement and should never be advanced further into the chest following placement because of the risk of infection.
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