The sign “NPO” often seen on a hospital door is a medical directive indicating a patient must abstain from taking anything by mouth. NPO is an abbreviation for the Latin phrase nil per os, which translates to “nothing by mouth.” This strict instruction is a standard safety precaution used in healthcare settings, most commonly before scheduled surgeries or certain diagnostic tests. The acronym serves as a clear, immediate communication tool for all hospital staff and visitors regarding the patient’s temporary dietary restriction.
The Strict Meaning of NPO
The instruction “nothing by mouth” means exactly that, with no exceptions unless specifically approved by a physician or nurse. This restriction goes beyond solid foods and includes all forms of liquids, such as water, juice, coffee, and even clear liquids like broth or tea. Patients are also prohibited from consuming ice chips, chewing gum, or sucking on hard candies or mints. Even if these items are not swallowed, the act of chewing or sucking stimulates the production of stomach acid and digestive fluids. This stimulation can be problematic during a medical procedure, which is why the rule is enforced so strictly.
Primary Medical Reasons for the Order
Aspiration Risk
The primary medical reason for an NPO order is to prevent pulmonary aspiration during general anesthesia. Anesthesia causes a loss of protective reflexes, including the gag reflex and the ability to cough. If food or liquid is present in the stomach, the patient may passively regurgitate the contents into the back of the throat. These stomach contents, which include acidic digestive fluids, can then be inhaled or “aspirated” into the lungs, leading to severe lung injury, chemical pneumonitis, or aspiration pneumonia. Patients are instructed to fast for a specific period, typically eight hours for solid foods and two hours for clear liquids, to ensure the stomach is empty before the procedure.
Diagnostic Testing
NPO status is also frequently required before certain diagnostic tests to ensure accurate results and clear imaging. Blood tests, such as fasting glucose or lipid panels, require a fast (usually eight to twelve hours) so that recent food intake does not skew the measurements. Procedures that examine the digestive tract, such as endoscopies or colonoscopies, also require an empty stomach and bowel. This ensures the physician has an unobstructed view during the examination.
Guidelines for Patients and Visitors
Adhering to the specific time window provided by the healthcare team is necessary to prevent delays or cancellation of the procedure. The old standard of “NPO after midnight” is often replaced by more specific instructions aimed at minimizing discomfort from prolonged fasting. Patients must confirm the exact time they should stop eating solid food (usually six to eight hours before) and stop drinking clear liquids (often two hours before).
Certain medications, particularly those for heart conditions or seizures, may need to be taken on the morning of the procedure. In these cases, the patient must take the approved medication with only a small sip of water, following explicit instructions from the nursing staff. Visitors also have a direct responsibility in maintaining the patient’s NPO status, and must refrain from offering any food, drink, gum, or mints, as violating the order can lead to the postponement of a scheduled procedure.