Understanding the Purpose of NBM
NBM, or nil by mouth, is a medical instruction that prohibits a patient from taking any food, drink, or medications orally. While most commonly associated with preparing for surgery, it is a crucial safety measure for a variety of other conditions. The primary goal is to protect the patient's airway and lungs from aspiration—the accidental inhalation of foreign material into the respiratory tract. When a patient is unconscious, has a compromised swallowing reflex, or is undergoing a procedure involving anaesthesia, the normal protective reflexes are diminished, increasing the risk of aspiration pneumonia. For gastrointestinal issues, NBM gives the digestive system a vital period of rest to heal.
Core Reasons for a Nil by Mouth Order
- Pre-operative Fasting: Before general anaesthesia, patients must fast for a specified period. This ensures the stomach is empty, significantly reducing the risk of regurgitation and subsequent pulmonary aspiration during the procedure. Fasting times vary depending on the type of substance and patient age, with solids typically requiring a longer period than clear fluids.
- Dysphagia (Swallowing Difficulties): Patients with neurological conditions like stroke, head injury, or neurodegenerative diseases may have an impaired or unsafe swallow. An assessment by a Speech and Language Therapist (SLT) can confirm the risk, and an NBM order is then implemented to prevent food or liquids from entering the lungs.
- Gastrointestinal Conditions: In cases of gastrointestinal bleeding, acute pancreatitis, or bowel obstruction, NBM is required to rest the gut and prevent further aggravation of the condition. Patients post-gastrointestinal surgery may also remain NBM until bowel function returns.
- Reduced Level of Consciousness: Patients who are unconscious, drowsy, or confused are often placed on an NBM status because they cannot safely manage oral intake.
- Severe Nausea or Vomiting: For patients experiencing severe vomiting, an NBM order helps manage symptoms and prevents further dehydration and electrolyte imbalance.
- Specific Medical Procedures: Fasting may be necessary before certain diagnostic tests, such as an endoscopy, to ensure a clear field of vision for the medical team.
The Role of Nutritional Support During NBM
When a patient is kept NBM for an extended period, the medical team must ensure their nutritional and hydration needs are met through alternative means. Prolonged fasting can lead to dehydration, malnutrition, and other complications, so appropriate care is essential.
Alternative Nutritional Methods
- Intravenous (IV) Therapy: For short-term NBM, IV fluids can maintain hydration and deliver electrolytes. In more complex cases, IV nutrition may provide essential calories and nutrients.
- Enteral Feeding: If the patient's gut is functional but they cannot swallow, a feeding tube can be inserted into the stomach (gastrostomy) or small intestine (jejunostomy). A nasogastric tube may also be used for shorter durations, running between the nose and stomach.
- Total Parenteral Nutrition (TPN): For patients with a non-functional or inaccessible gastrointestinal tract, TPN delivers all necessary nutrients intravenously.
Nursing Considerations and Patient Care
Effective management of an NBM patient requires diligent nursing care and clear communication among all healthcare staff, as well as the patient and their family. Critical aspects of this care include:
- Mouth Care: Keeping the mouth clean and moist is paramount for NBM patients. It helps prevent oral infections and reduces discomfort associated with a dry mouth, which is a common side effect of prolonged fasting. Nurses may provide mouthwashes or moisturizing swabs to assist with oral hygiene.
- Medication Management: Any medications typically taken orally must be reviewed. The medical team will decide whether to switch to an alternative route, such as intravenous, or to temporarily stop the medication.
- Clear Documentation: The NBM order must be clearly documented in the patient's records, including the reason, the date and time it commenced, and the planned review time. Clear signage should also be placed near the patient to prevent accidental intake.
- Psychological Support: Being unable to eat or drink can be distressing for patients. Explaining the reasons for the NBM order and the care plan can help reduce anxiety and improve compliance.
Comparison of NBM Scenarios
| Feature | Pre-operative Fasting | Dysphagia-Related NBM |
|---|---|---|
| Primary Reason | Reduce gastric contents to prevent aspiration during anaesthesia. | Protect the airway from aspiration due to unsafe swallowing. |
| Typical Duration | Short-term; generally a few hours, though varies by food/liquid type. | Variable; can be short-term following a stroke or long-term for chronic conditions. |
| Medical Oversight | Managed by the anaesthetist based on procedural guidelines. | Determined and reviewed by a Speech and Language Therapist and the medical team. |
| Patient's Conscious State | Typically conscious during the fasting period, but will be unconscious or sedated during the procedure. | Can be conscious but unable to swallow safely, or have a reduced level of consciousness. |
| Nutritional Management | Post-procedure feeding is reintroduced quickly, often on the same day via an enhanced recovery program. | May require long-term alternative feeding methods like enteral or parenteral nutrition if a return to oral intake is unsafe. |
Conclusion
NBM is not a one-size-fits-all instruction but a highly specific medical intervention tailored to a patient's clinical needs. From pre-operative fasting to protecting a patient with impaired swallowing, its primary role is to ensure patient safety and facilitate healing. It is a critical component of care for conditions affecting consciousness, gastrointestinal function, and the ability to swallow. Through coordinated medical and nursing care, including appropriate alternative hydration and nutritional support, the risks associated with being nil by mouth can be effectively managed, ensuring the best possible outcome for the patient. For more information on patient care standards, review the guidelines from the Royal College of Physicians of Edinburgh.
The Risks of Aspiration
When a patient aspirates, stomach contents, saliva, or other fluids can enter the lungs. This can cause a severe inflammatory reaction, leading to aspiration pneumonitis. In some cases, it can progress to aspiration pneumonia, a serious and potentially life-threatening chest infection. The risk is highest during anaesthesia when protective airway reflexes are suppressed. Aspiration can also occur in patients with dysphagia who are awake but cannot swallow safely. This is sometimes referred to as "silent aspiration" if the patient does not cough or show obvious signs of choking. Protecting patients from this risk is the single most important reason for an NBM order.
Managing Long-Term NBM
For patients requiring NBM for an extended period, such as those with severe or permanent dysphagia, the focus shifts to comprehensive nutritional and hydration planning. A multidisciplinary team, including doctors, nurses, dietitians, and Speech and Language Therapists, works together to develop a care plan. This may involve the insertion of feeding tubes for enteral nutrition or, in more complex situations, the use of TPN. Patient education and psychological support are also vital to help individuals and their families cope with the implications of long-term oral restrictions.
