Enteral tube feeding, especially the bedside NG tube feeding, is a crucial feeding method used in patients who are unable to meet their nutrition needs orally. However, it might be associated with side events complications and may worsen the prognosis of patients. With the development of the position determining methods, the incidence of malposition has decreased to a certain extent. Nevertheless, during the blind bedside placement, inadvertent malposition into the lung, trachea or the pleural cavity still occurs frequently. We described the case of an elderly man who presented with malposition of nasogastric tube into the right pleural space. In this patient, NG tube placement failure was mainly caused by his anatomical issues, the methods to ensure NG tube position, the intubation method, or it may be related to the auxiliary means.
Anatomically, this patient suffered from nasopharyngeal carcinoma after radiotherapy and chemotherapy, movement and sensory disorders in throat muscle. Thus, he was at high risk of NG tube misplacement. This was in accordance with previous studies, among patients treated with radiotherapy, dysphagia occurs frequently by damage to neural and soft tissues, such as soft tissue fibrosis and neurological impairment. In addition, Honghong L et al. reported radiotherapy often alters the sensitivity of the swallowing structures in patients with nasopharyngeal carcinoma, which may result in a deficient cough reflex. The cough reflex disappearance can cause misplacement of the tube in the trachea. We speculated this was the reason why this patient underwent NG tube malposition without symptoms such as cough during inserting and feeding process.
Since severe complications or death can be caused by misplaced NG tubes into the lung or tracheobronchial tract, it is of vital importance to the methods that confirming the position of NG tube. At present, various methods are employed to determine the placement of the NG tube, including radiography, respiratory distress, pH test, auscultation, carbon dioxide detection, auscultation, and enteral access devices. Among these testing methods, radiography is regarded as the gold standard to distinguish between gastric and pulmonary placement[20–22]. Of non-radiographic methods, pH testing was the most popular method, and epigastric auscultation is least favored. In our case, the nurse confirmed the position together with the doctor through suction of gastric contents and epigastric auscultation through injecting air into the gastric tube, which were commonly used. Besides, 40 ml warm water was fed through NG tube, and the patient had no adverse reactions such as choking, signs of respiratory distress, etc. Nevertheless, the bedside radiography was not carried out immediately because of its deficiency, such as delayed enteral feeding administration and the risk of radiation exposure to patients [24–26]. Unfortunately, this patient encountered malposition of the NG tube. This adverse event indicated that the reliability of generally confirmation methods we chose with simple operation in clinical practice still needed to be validated. Previous research has proved that even if the NG tube is mal-positioned in the lung, or in the pleural cavity after perforation, the sound may still be heard. And a small amount of fluid aspirated may not be distinguished from tracheal secretion. Therefore, as long as the patients at high risk of NG tube malposition, they should receive a radiograph to confirm the proper position of NG tube before initiating feedings. However, it was worth noted that the radiologist performed bedside chest radiography for this patient twice because of severe chest pain, but they did not report the gastric tube was in the lungs or bronchi. Possible explanation was that the relationship of image quality and radiation dose was more complex in the routine radiography practice . On the other hand, the silicone NG tube may not develop clearly because of the imprecise radiation dose or increased image noise during the radiography process . Though radiographic examination is the most accurate method, this finding implied that the radiologist should choose the right radiation dose to ensure excellent image quality if we aimed to verify the position of NG tube.
Traditionally, the NG tube insertion is performed by nursing staff blindly, as we know, this requires skilled operational skills and rich practical experience. Besides, the anesthetic or instrument may be used to assist NG tube insertion. In this patient, the front end of the NG tube was smeared with tetracaine hydrochloride gel before intubation to ensure insert more smoothly. Actually, application of tetracaine hydrochloride gel could reduce the occurrence of uncomfortable reactions such as vomiting and coughing during intubation [31, 32]. Using it to perform surface anesthesia on patient’s nasal cavity and throat mucosa that causes temporary loss of sensation, reduces the sensitivity of the superior laryngeal nerve, thus effectively easing the patient’s nausea and vomit. However, for patients with impaired swallowing and muscle function, it will cover the adverse alert such as irritating cough that indicates the gastric tube enters the airway by mistake. Therefore, in our case, as this patient suffered from nasopharyngeal carcinoma after radiotherapy and chemotherapy, the tetracaine hydrochloride gel should not be used commonly.
Fortunately, misplacement of the gastric tube into the lung or trachea will be avoided under direct visualization using a video laryngoscope. Video laryngoscope-assisted nasogastric tube placement enables the operator to see if the tube has or has not entered the esophagus and to correct any non-esophageal placement, and this way helps advance the tube correctly into the esophagus. Especially for patients with nasal contraindications who are influenced by physiological and pathological factors, traditional methods are not easy to succeed. A Meta-analysis compared the gastric tube insertion under video laryngoscope with the gastric tube insertion immediately, the results indicated insertion under video laryngoscope significantly reduce the incidences rate of stray trachea . Tadashi’s study showed that misplacement of the gastric tube in the trachea could been detected and corrected under the vision of video laryngoscope . Hence, the operator could insert the NG tube with the assist of a video laryngoscope to avoid failure .
Most importantly, we should observe the patient’s condition closely, and pay attention to his chief complaint of symptoms. For this patient, even though he had no choke after NG tube insertion, severe chest pain was reported repeatedly. This might be the vital signal of NG displacement into the lung or trachea. Unfortunately, our physicians and nurses ignored this crucial signal that indicated the NG tube of displacement.