A pneumothorax is present when there is air in the pleural space. Pneumothoraces are classified as spontaneous, which develop without preceding trauma or other obvious cause, and traumatic, which develop as a result of direct or indirect trauma to the chest. Traumatic pneumothoraces can be either iatrogenic or non-iatrogenic. Iatrogenic pneumothoraces (IP) occur as a result of certain diagnostic or therapeutic procedures and constitute the current indicator (Light RW, 2016).
A tension pneumothorax is present when the air accumulates in the pleural space to a point where the increasing pressure in the pleural space impedes normal cardiovascular function. Tension pneumothorax can occur with any of the types of pneumothorax but occur more commonly - although not exclusively - to patients receiving positive pressure ventilation or CPR. It can lead - often quite suddenly - to life-threatening hypotension and shock, making it a medical emergency (Light RW, 2016).
Iatrogenic pneumothoraces is a potentially life-threatening complication seen in three per cent of ICU patients (Chen, 2002; Anzueto, 2004; De Lassence, 2006). It has been associated with an increase in ICU and hospital length of stay and resource utilization (Amato, 1998; Anzueto, 2004; De Lassence, 2006; Zhan, 2006) as well as an increase in the risk of death (Gattinoni 1994, Schnapp 1995, Esteban 2002). Despite doubt cast by a retrospective review (Weg, 1998), this increase was recently quantified as twice that of ICU patients without iatrogenic pneumothorax and similar to the risk of death associated with ventilator-related barotrauma or post-procedural pneumothorax (De Lassence, 2006). In addition to tension pneumothorax, systemic air embolism is a rarer but potentially lethal complication of ventilator-related pneumothorax (Azad, 2011; Ibrahim, 1999).
IP is largely preventable (De Lassence, 2006). In the ICU setting, the currently low three per cent incidence of IP in ICU patients was around eight per cent in the 1980s (De Lassence, 2006). This decrease is believed to be due to improved equipment, techniques and safer practices both for mechanical ventilation- and procedure- related pneumothorax (Celik, 2009):
- The significant decrease in pneumothorax related to mechanical ventilation over the last decades coincides with the implementation of improved "lung-protective" ventilation strategies (The ARDS Network, 2000; Miller, 2008). However, recent case series demonstrate no relationship between the incidence of barotrauma and ventilatory settings (Weg, 1998; Briel, 2010; Hsu, 2014). It may be that more factors were involved in this decrease than simply protective lung strategies, such as improved ventilators, overall ventilator care and treatment of the underlying disease processes. One example is the reduction of pneumothorax in ventilated patients with ARDS when administered neuromuscular blocking agents in the first two days of ventilation (Papazian, 2010).
- The incidence of procedure-related pneumothorax has also been reduced by improved equipment (e.g. ultrasound), and education and training; these improvements have equally been noted in the non-ICU and pediatric settings (Duncan, 2009; Gordon, 2010; Havelock, 2010; Lenchus, 2010; Cavanna, 2010; Troianos, 2012).
To prevent iatrogenic pneumothorax in hospitalized adult patients by implementing best practices for risk reduction.
Procedures Associated with Iatrogenic Pneumothorax
Dry needling (Health Quality Council of Alberta, 2014): this term refers to interventional techniques (diagnostic or therapeutic) that use a solid filament needle to puncture the skin. A non-exhaustive list pertaining to iatrogenic pneumothorax includes: central venous catheterization (subclavian or internal jugular), thoracentesis (greater if indication is therapeutic vs diagnostic) (Gordon, 2010), transthoracic needle aspiration and percutaneous biopsy of the lung (Cox, 1999; Choi, 2004), pleura or liver, radiofrequency ablation of lung tumors, intercostal nerve block, acupuncture, and brachial plexus block (supra- or infraclavicular approaches).
Airway-related: endotracheal tube insertion (intubation) or misplacement (neonates), inadequate clearance of trapped secretions, positive airway pressure devices (Carron, 2007; Chebel, 2010; Hegde, 2013; Milési, 2014) including mechanical ventilation, transbronchial lung biopsy, inadvertent endobronchial placement of small nasogastric/feeding tubes, bronchoscopy (rigid, fiberoptic (diagnostic or interventional) – more frequent in children.
Surgical: tracheostomy, thoracotomy, mediastinoscopy, cardiac surgery, insertion/revision/replacement/removal of cardiac pacemaker or cardioverter/defibrillator, breast augmentation, rarely: abdominal cavity operations.
Other: cardiopulmonary resuscitation (CPR).
In these series (most enumerate patient risk factors, see below), central venous catheterization, thoracentesis and mechanical ventilation are the most commonly reported procedures in adults and Pediatric case series (Johnson, 2010). For central venous insertion and thoracentesis, additional risk factors are the need to do two to three, or more needle passes and staff inexperience (Bailey, 2000; Molgaard, 2004; Gordon, 2010). Risk factors have also been described with specific procedures (e.g. transthoracic needle aspiration or biopsy (Haynes, 2010)).
In most healthcare institutions, healthcare professionals are authorized to practice these interventions by the institution’s Medical Director based on professional accreditation and clinical competency.
Patient Risk Factors
Patient factors that increase the risk of pneumothorax in the setting of an intervention include:
- Low body weight
- Poor healing ability (chronic corticosteroid use, malnutrition)
- Severity of acute illness
- Acute or chronic pulmonary or pleural disease