During most surgeries, the patient is made unconscious and paralyzed to protect him from pain and damage from involuntary movement. As a result of this paralysis, machines called ventilators must take over the work of breathing for the patient. A tube called an endotracheal tube is typically inserted into the airway to provide oxygen, remove carbon dioxide and protect the lungs from gastrointestinal fluids. Some relatively common complications of this procedure--called intubation--include barotrauma, nosocomial pneumonia and tracheal stenosis.
The term barotrauma refers to damage to the lungs and airways as a result of excessive pressure generated by mechanical ventilation. It can result in pockets of air developing in the skin--also known as subcutaneous emphysema--or chest cavity. Subcutaneous emphysema is typically benign and will resolve on its own. However, air in the chest cavity can interfere with lung function and may require the placement of a chest tube to drain the excess air. According to Barry Brenner et al in the August 2009 issue of "The Proceedings of the American Thoracic Society," the risk of barotrauma is increased in patients with underlying airway conditions such as asthma.
Pneumonia is an infection of the lungs, and the term nosocomial refers to a condition that originates in a hospital. The act of being intubated and placed on a ventilator is invasive and may introduce bacteria into the airways. In addition, the 17th edition of "Harrison's Principles of Internal Medicine" states that remaining on a ventilator for more than 72 hours results in a high risk for pneumonia due to leakage of contaminated secretions around the endotracheal tube and into the lungs. Every effort should be made to minimize time spent on a ventilator and to target antibiotic therapy aggressively at the first sign of pulmonary infection.
Tracheal stenosis refers to narrowing of the airway that may become severe enough to interfere with breathing. Typically, stenosis develops at the site of the endotracheal tube cuff. This cuff is inflated during intubation to protect the airway from aspiration, or the passage of saliva or gastrointestinal contents into the lungs. It may press hard enough against the inside of the trachea to cause damage to the tissue. This tissue swells and scars as it heals, causing narrowing of the airway. The second edition of "Current Diagnosis and Treatment in Otolaryngology" reports that this complication occurs in 8 to 13 percent of ventilated patients.