Could the presence of a Nasogastric (NG) tube in a patient with Herpes Simplex Virus-1 (HSV-1) Encephalitis and autoimmune diseases contribute to failed swallow tests and absence of reflux in the context of a recent pneumonia diagnosis?

From the Guidelines

The presence of a nasogastric (NG) tube in a patient with Herpes Simplex Virus-1 (HSV-1) Encephalitis and autoimmune diseases can contribute to failed swallow tests and absence of reflux, potentially leading to pneumonia development, as the tube may cause mechanical irritation and suppress normal swallowing reflexes, and alternative feeding methods like a percutaneous endoscopic gastrostomy (PEG) tube should be considered if swallowing difficulties persist. In patients with HSV-1 encephalitis, neurological impairment already affects swallowing coordination, and this can be exacerbated by the physical presence of the NG tube 1. Autoimmune diseases further complicate the situation by potentially causing inflammation or neurological dysfunction that impacts swallowing mechanisms. The tube itself can serve as a conduit for bacteria to enter the lungs through microaspiration around the tube, contributing to pneumonia development. Additionally, the tube may mask normal protective reflexes like coughing or gagging that would typically prevent aspiration. Some studies suggest that early nutrition via PEG in mechanically ventilated patients with stroke or head injury is superior to feeding via nasogastric tube, and it is associated with a lower prevalence of ventilator-associated pneumonia 1. However, other studies have found no significant differences in the risk of pneumonia and overall complications between nasogastric tube feeding and PEG feeding in older patients with non-stroke dysphagia 1. Regular assessment of swallowing function after temporary removal of the NG tube (if medically appropriate) could provide a more accurate evaluation of the patient's true swallowing capabilities without the mechanical interference. It is essential to weigh the benefits and risks of each feeding method and consider the individual patient's needs and circumstances. Key considerations include:

• The potential for mechanical irritation and suppression of normal swallowing reflexes with NG tubes
• The risk of pneumonia development with NG tubes
• The potential benefits of alternative feeding methods like PEG tubes
• The importance of regular assessment of swallowing function
• The need to consider the individual patient's needs and circumstances when deciding on a feeding method. In general, the decision to use a NG tube or a PEG tube should be based on the individual patient's condition, the anticipated duration of enteral nutrition, and the potential risks and benefits of each method 1. Ultimately, the goal is to provide adequate nutrition while minimizing the risk of complications and promoting the best possible outcomes for the patient.

From the Research

Presence of Nasogastric Tube and Swallowing Function

• The presence of a nasogastric (NG) tube in patients can affect their swallowing function, potentially leading to failed swallow tests 2.
• Studies have shown that NG tubes can cause anatomical and physiological changes, such as loss of upper and lower esophageal sphincter integrity, increased frequency of transient lower esophageal sphincter relaxations, and desensitization of the pharyngoglottal adduction reflex, which can contribute to aspiration and swallowing difficulties 3.

Aspiration Pneumonia and Nasogastric Tube

• Aspiration pneumonia is a common complication in patients with NG tubes, and the presence of the tube can increase the risk of aspiration due to factors such as displacement of the tube, inappropriate feeding posture and speed, and excessive gastric residual volume 4.
• However, one study found that the presence or absence of an NG tube in the same person did not significantly affect the incidence of anterograde aspiration 5.

Reflux and Nasogastric Tube

• The presence of an NG tube can lead to gastroesophageal reflux, which can contribute to aspiration pneumonia 4.
• However, the study by 3 suggests that the kind of bacterial contamination is more difficult to establish, and oral or dental disease, antibiotic therapy, systemic illness or malnutrition, and reduction of salivary flow are responsible for colonization of Gram-negative bacteria in oral and pharyngeal flora in nasogastric-tube-fed patients.

Autoimmune Diseases and Herpes Simplex Virus-1 (HSV-1) Encephalitis

• There is limited evidence directly linking autoimmune diseases and HSV-1 encephalitis to the presence of an NG tube and swallowing function.
• However, patients with these conditions may be more susceptible to complications such as aspiration pneumonia, and the presence of an NG tube should be carefully managed to minimize this risk 4, 2.