During the early years of medical school especially in the first year of starting clinical rotations, it is not uncommon to find lots of medical abbreviations and not have a clue as to what they mean. In this post, we will be discussing one of such terminologies; ‘Medical Abbreviations NPO’.
Also, if you are currently sick and are preparing for surgery, or have someone under your care who is preparing for surgery, then this post will be of help.
So what does the medical term NPO mean?
Below is the meaning of the medical abbreviation NPO. And also the reason why medical terminology is important, and why doctors still use them today.
Table of Contents
- Medical Abbreviations NPO; Origin, Meaning and Why It Is Used
- Medical Abbreviations NPO; Duration
- Why Medical Terminology Is Important
- Medical Abbreviations NPO; Take Home
Medical Abbreviations NPO; Origin, Meaning and Why It Is Used
The full meaning of the medical abbreviation NPO is ‘Nothing By Mouth’. It is derived from the Latin terms ‘Nil Per Os’.
Nil meaning Nothing
Per meaning By
Os meaning mouth
What Does The Medical Term NPO Mean?
The medical abbreviation NPO meaning Nothing By Mouth is used to describe a situation when a patient is expected not to eat or drink neither food nor water especially before and after a surgical procedure.
In other terms, it could be translated as Withhold food and fluids or Complete bowel rest. The latter refers to when the whole gastrointestinal tract is allowed to be at rest; without peristalsis.
Nil Per Os is most commonly used among the surgical specialists who are working up a patient for surgery or following up a patient after surgery.
Various Reasons Why The Medical Abbreviations NPO Is Used

The medical abbreviation NPO is used mainly as a precaution and a safe approach to prevent complications due to bowel movement during certain medical and surgical procedures.
The theory behind this practice is that fasting before surgeries reduces the risk of aspiration pneumonitis. A term used to describe a condition when the contents of the stomach move up the esophagus and finds their way into the lungs through the airways resulting in severe complications and might lead to death due to inflammation and irritation of the lungs.
Patients are at risk of aspiration pneumonia during certain surgeries especially those that require general anesthesia or cutting open of the belly (abdomen).
Medications used during general anesthesia cause a relaxation effect on the smooth muscles of the bowels. This reduces the peristaltic movement needed to push the contents of the intestines forward. This laxity of the intestinal walls makes the backward movement of food and water in the intestines possible resulting in aspiration of such into the airways.
Some Medical conditions where the medical term Nil Per Os Is used;
- Gastrointestinal bleeding
- Gastrointestinal blockage
- Acute pancreatitis
- Alcohol intoxication resulting in vomiting
- Fasting Blood Sugar test for diagnosis of diabetes
- Colonoscopy
- Gastric fluid aspiration and sampling
- Before taking some medications
- Abdominopelvic Surgeries like;
- Cesarean section
- Appendicectomy
- Colostomy
- Uterine fibroid removal
- Herniorrhaphy
- Splenectomy
- Hepatic Lobectomy
- Other major surgeries where general anesthesia is used.
In a case where a patient was unable to maintain the Nil Per Os status before presenting to the hospital for elective surgery (Non-emergency surgical cases), the surgery is usually delayed till the Nil per os status is reached.
Medical Abbreviations NPO; Duration
The duration a patient needs to stay without food or water before a procedure varies depending on the procedure. Also, the NPO protocol is observed both before and after the surgery until the patient is able to tolerate oral food.
During this time, the patient is kept on a Total Parenteral Nutrition (TPN) to cater to their energy needs. The total parenteral nutrition simply means that the patient is given intravenous fluids until they can take food and water orally. The fluids used for total parenteral nutrition should contain an optimum quantity of sugar (Dextrose containing fluids are used).
So how long should NPO last?

Pre-Surgery NIl Per Os Duration
Pre-surgery NPO simply means that the patient should not eat or drink anything before the surgery.
The duration of presurgery Nil per Os is usually between 6 to 12 hours depending on the surgery. This time may be longer if long-acting medications or oral post-op medications are administered.
The duration for food restriction is usually 8 hours before the surgery and 2 hours for fluid restriction to reduce gastric volume. This is in accordance with the American Board of Anesthesiologists guideline for the Nil per Os protocol.
Post Surgery Nil Per Os Duration
The medical abbreviation NPO is used after surgery in a patient to enable time for full recovery of the bowels. There is no strict protocol for Nil per os after surgery, but the ideal time for patients to commence oral intake of food and water after surgery is when there is evidence of bowel movement.
This can be elicited on a bedside by the use of a stethoscope placed on one-third of an imaginary line from the belly button (umbilicus), to the upper part of the hip bone on any side (anterior superior iliac spine).
Why Medical Terminology Is Important
There are many misconceptions as to why doctors use medical abbreviations and terminologies. I used to think that medical terminologies are used by doctors as a tool to intimate people who are not in the medical field, this is the same for a lot of people and maybe true for some medics who do not understand the reason behind using them.
Also, the recent upsurge in patient-centered care where patients fully participate in their management plan has made this belief invalid. The increase in the number of health education television channels, YouTube channels, and health blogs has also refuted this claim.
But here are some of the reasons why medical terminologies are still in use;
The Theory Of Origin
The original fathers of modern medicine were the Greek philosophers and in those times, Latin and Greek were regarded as the languages of the elites and enlightened. So ancient medical texts were written in Latin and Greek. Also, the different parts of the body were named in Latin and Greek. So for one to become a doctor of modern medicine, they must first be proficient in Latin and Greek.
But with the advent of western civilization and the widespread of the English Language, there was a need for doctors to share medical knowledge in a language that will be understood by their students.
Hence, all the written texts and terms needed to be translated into English for easy communication.
Some of the terms in the original texts did not have a suitable transliteration into the English Language, and they were left as a corruption of Latin, Greek, and English. This gave rise to the medical terminologies you hear today.
Ease Of Use
One important reason why medical terminology is important (when used as an abbreviation) is for ease of use. Imagine being a doctor in a clinic with scores of patients waiting to be attended to and having to write ‘Non-Steroidal Anti-inflammatory Drug’ as a treatment for a patient.
The most natural thing for a ‘fully initiated medic’ is to write ‘NSAIDS’ instead of a Non-Steroidal Anti-inflammatory drug. It not only saves your time and that of the patients in waiting, but it also reduces stress and burnout.
It is good to note that the recognized medical terminologies are universally accepted by practicing physicians all over the world.
Also, Read
Want To Learn More Medical Abbreviations? Get the Stedman’s Medical Abbreviation Dictionary From Amazon using the button below.
Medical Abbreviations NPO; Take Home
What does the medical term NPO mean?
The medical term NPO is an abbreviation of the Latin term Nil per Os which means nothing by mouth. It is used to describe a situation where a patient is not expected to take fluid or food orally usually before or after a medical or surgical procedure.
What duration is ideal for standard NPO protocol?
The ideal duration of Nil per oral before a surgical procedure is between 6 to 12 hours. And after surgery, it is until there is evidence of bowel activity. For some medications, it can be as little as 30 minutes.
Why doctors Use Medical Terms
Many medical terms used today are a corruption of Latin and Greek languages which are the original languages of the fathers of medicine. Medical abbreviations are used due to their ease of use.
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