A nasogastric (NG) tube is a flexible, thin tube inserted through the nose, down the throat, and into the stomach. These tubes serve medical purposes, including delivering liquid nutrition, medications, and fluids directly to the stomach. They are also used to remove substances from the stomach, such as relieving pressure from excess fluid or air, or removing toxins. Precise placement of the NG tube in the digestive tract is necessary. Incorrect placement, particularly in the respiratory system, can lead to serious complications.
Recognizing Misplacement
Identifying when an NG tube has been inadvertently placed in the respiratory tract is important for preventing complications. Patients may exhibit signs that suggest misplacement. Common indicators include sudden coughing or choking during insertion, which can signal the tube entering the airway. Some individuals might experience difficulty breathing or show signs of respiratory distress.
Changes in vocal quality, such as hoarseness, or the inability to speak are also potential signs of misplacement. Cyanosis (bluish discoloration of the skin or mucous membranes) may occur due to reduced oxygen levels if the tube obstructs the airway. However, these signs can be subtle or absent, especially in sedated, unconscious, or mentally altered patients. This emphasizes the need for careful monitoring and confirmation.
Immediate Health Risks
The presence of an NG tube in the lungs, or the administration of substances through it into the respiratory system, poses serious health risks. A common complication is aspiration pneumonia. This occurs when stomach contents, tube feed, or medications are introduced into the lungs, leading to inflammation and infection of the lung tissue. Aspiration pneumonia can cause acute respiratory distress, leading to severe breathing difficulties and low oxygen levels, sometimes requiring mechanical ventilation.
Another danger is pneumothorax (a collapsed lung), which can result from the tube perforating lung tissue or the pleural space during insertion. This can lead to air leaking into the space between the lung and the chest wall, causing the lung to collapse. Fluid accumulation, such as hydrothorax or empyema, can also occur in the pleural cavity if tube feeds enter this space. These complications highlight the severity of misplacement and potential lung damage.
Confirming Tube Location
Medical professionals employ specific methods to verify NG tube position before use. The most reliable method is a chest X-ray. A chest X-ray provides clear visual confirmation of the tube’s path, ensuring it has passed through the esophagus and is correctly positioned within the stomach, typically below the gastroesophageal junction. This imaging helps rule out coiling in the esophagus or entry into the respiratory tract.
Another diagnostic tool is pH testing of aspirate, which involves drawing fluid from the tube and testing its acidity. Gastric contents are acidic (pH less than 5.5), while fluid from the respiratory tract tends to be more alkaline. While X-rays are important for initial placement, pH testing can be used for ongoing checks. Less reliable methods, such as auscultation of air insufflation (listening for air sounds over the stomach) or visual inspection of the aspirate, are not sufficient for confirmation and are not recommended as primary methods. Accurate confirmation is necessary to prevent severe complications before any feeding or medication administration.
Corrective Actions and Recovery
Once misplacement of an NG tube in the lungs is confirmed, healthcare providers take immediate corrective actions. The first step is prompt removal of the misplaced tube. Following removal, continuous patient monitoring is necessary to assess for signs of respiratory distress, such as increased breathing effort or changes in oxygen saturation.
Medical treatment is initiated based on complications. If aspiration pneumonia is suspected, antibiotics are prescribed to treat the infection. Oxygen therapy may be provided to support breathing, and in severe cases of respiratory compromise, mechanical ventilation might be necessary. For a pneumothorax, a chest tube may be inserted to drain air from the pleural space and allow the lung to re-expand. Recovery varies depending on complication severity, but close patient monitoring for several days is standard to ensure no further issues develop.