What are the 5 W’s of Post-op Fever?

If you or someone you know is recovering from surgery, they may experience post-op fever. It’s normal to have concerns about this condition and what it means for the healing process. Post-op fever can be a sign of an infection or other problem in the body, so it’s essential to understand what it is and how to manage it once it occurs.

In this blog post, we’ll look at what post-op fever or post-op fever 5 w’s is, why it happens, who is prone to getting it, and management options that can help reduce its symptoms. We’ll also discuss when you should seek medical attention if needed so that recovery goes as smoothly as possible.

What is Post-op Fever?

Postoperative fever is a common occurrence after undergoing surgery. An elevated body temperature of 38.5°C or higher indicates something may be amiss, but determining the cause can be challenging. While postoperative fever may be nothing to worry about, it can also mean a complication from the surgery, such as an infection.

The key to successfully treating postoperative fever is identifying the underlying cause and taking the appropriate steps to address it. So if you or someone you know experiences fever after a recent surgical procedure, it’s essential to seek medical attention and get to the root of the issue as soon as possible.

Cause of Post-Operative Fever

Medical students are often taught a mnemonic beginning with the letter W to recall the most common causes of postoperative fever. The mnemonic 5 w’s of Post-op fever are often taught to remember the reasons. They are:

Category Timing Causes
Wind POD 1-2 Pneumonia, aspiration, pulmonary embolism, but not atelectasis
Water POD 3-5 Urinary tract infection
Wound POD 5-7 Infection of the surgical incision(s), either superficial or deep[4]
Walking (or VEINS pronounced like “Weins”) POD 5+ (risk may persist for months post-operatively) Deep vein thrombosis or pulmonary embolism
Wonder drugs or “What did we do?” Anytime Drug fever or reaction to blood products,
(W)abscess (Variation) POD 5-7 infection of an organ or space
Wing/Waterway (Variation) Anytime Bloodstream infection, phlebitis, or cellulitis

Two other potential sources should also be considered – Wing/Waterway and (W)abscess. Generally speaking, these complications tend to arise within a certain timespan after surgery (known as postoperative days or POD).

Other post-operative fever may also be caused by malignant hyperthermia, a potentially life-threatening reaction to inhalational anesthetics and paralytic agents. Fortunately, this condition can be treated if diagnosed promptly. Other causes of early post-operative fever are worth considering as well.

Postoperative fever within 48 hours is usually caused by tissue injury sustained during surgery, triggering an inflammatory response with sympathetic nervous system involvement. Anti-pyretic medications and extra fluids are sufficient treatment.

5 W’s of Post OP Fever: Rule of W (Mnemonic) & Management

1. Wind (lungs)

The first “W” in the acronym stands for wind, referring to a lung condition that leads to fever. When fevers appear within 24-48 hours after an operation, they are often related to atelectasis of the lungs. Postoperative fever is a common symptom associated with this occurrence.

At this stage, this 5 w’s of Post op fever is often a result of chest infections, pneumonia, aspiration, or even the collapse of all or part of the lung, known as atelectasis. This is a common consequence of general anesthesia and occurs when the alveoli become deflated and filled with fluid. Furthermore, increased lung fluids can lead to infection (pneumonia).

Therefore, mobilization, deep breathing exercises, and expansion are essential for preventing infection. While some experts argue that atelectasis does not always cause fever, it should still be considered.

Any pain experienced by a patient post-surgery mustn’t go ignored as this will prevent them from taking deep breaths which could lead to an inability to expand their lungs and the onset of a pulmonary infection.

Pain relief should be prescribed accordingly, and regular assessments to ensure that the patient takes deep breaths into a spirometer throughout the day.

2. Water = UTI

The second “W” in the acronym stands for water, a reference to urinary tract infections (UTIs). UTIs are bacterial infections that can occur within 3 to 5 days after surgery and often cause fever in postoperative patients.

Statistics from the Centers for Disease Control (CDC) show that 75% of urinary tract infections are acquired in a hospital setting due to an inserted urinary catheter. Because of this, doctors usually urge patients to remove their Foley catheters quickly after surgery.

Urinary tract infections are caused mainly by bacteria that may have been tracking up to the kidneys. That is why treatment typically involves antibiotics to eliminate the infection.

As such, if this 5w Post op fever develops 3 to 5 days after an operation, it is crucial to consider the possibility of a urinary tract infection.

3. Wound = Infection

The third “W” in the acronym stands for wound, a reference to surgical site infections (SSIs). These bacterial infections occur at or near the area of surgery and often cause postoperative fever if not treated appropriately. SSIs may be caused by poor sanitation or improper wound care, such as not changing dressings regularly.

When a patient has a fever 5 to 7 days after surgery, it is most likely related to an infection of the wound—either superficial or deep.

As previously discussed, our body increases its temperature when fighting off infection to help the immune system do its job more effectively and potentially slow bacterial growth.

A small amount of heat surrounding the postoperative wound is average, but if it gets hotter, is redder, or has pustulent drainage, the wound may have become infected. This could lead to a fever throughout the body as well.

Healthcare professionals must act quickly on this type of fever since wound infection can spread rapidly and cause serious problems.​

4. W = Walking

The final “W” in the acronym stands for Walking, This is meant to represent a deep vein thrombosis (DVT) which is a blood clot in the leg. This can cause postoperative fever if it travels to the lungs and causes a pulmonary embolism (PE).

Thrombosis is a potential health hazard and can even be fatal. This medical condition usually involves the formation of a blood clot in deep veins, specifically those that carry blood from the legs to the heart.

When patients don’t move around after surgery, this causes their leg’s blood becomes stagnant and increases their risk of developing a thrombosis. That is why the 5 W’s mnemonic uses the term walking to emphasize how important it is for patients to move around after surgery.

Although DVTs are not usually deadly, some clots can get dislodged and travel to the lungs, leading to cardiac arrest or other severe issues. As such, preventing and treating DVTs as soon as possible is essential.

There is still debate about why a deep vein thrombosis can cause fever, but it is generally accepted that the two conditions are linked. If a patient has been sedentary after surgery and suddenly develops a fever 5 or more days later, doctors should consider the possibility of DVT.

5. W= Wonder (Drug Fever)

The fifth “W” in the acronym stands for the wonder drug. This refers to antibiotics used to treat many bacterial infections that can lead to postoperative fever. Fever caused by wonder drugs can occur at any time during or after surgery, which makes it challenging to identify as the timing overlaps with the other four possible causes of fever.

Antibiotics help kill bacteria and reduce inflammation, allowing the body to heal quickly and fight infection. It is important to note that antibiotics should only be taken when prescribed by a medical professional based on an individual’s diagnosis.

Check and look at the following:

  • IV/cannula sites. Are they any signs of infections?
  • Blood and transfusions.
  • Look at the medication charts, especially when it is new to the patient

Patients who develop postoperative fevers five or more days after surgery likely have an infection. In this case, doctors may recommend antibiotics. When taken correctly, these drugs can reduce symptoms like fever and pain and speed up healing time.

Other Types of variations of the 5 w’s Post Op Fever


The fifth “W” in the acronym stands for abscess. An abscess is an infection that can occur in soft tissues or organs after a procedure. It typically occurs around the same time as wound dehiscence, which is often associated with it. Abscesses usually require drainage and cleaning.


This message indicates that someone has an infection in their bloodstream, also known as sepsis. The source of the infection can be challenging to pinpoint and manage, so it’s important to begin treatment with broad-spectrum antibiotics quickly. It’s also important to practice responsible use of antibiotics.

Final Words

The 5W acronym is a helpful tool for diagnosing and treating postoperative fevers. Although other things can cause fever, the five “W’s” cover most things that could lead to an elevated temperature. It’s essential to accurately diagnose and treat postoperative fever as soon as possible to reduce the risk of serious complications.

Practicing responsibly using antibiotics and other medications when necessary is also essential. Knowledge of the 5 W’s mnemonic allows postoperative fever to be quickly diagnosed and treated for better patient outcomes.


  • https://en.wikipedia.org/wiki/Postoperative_fever#References
  • https://www.ncbi.nlm.nih.gov/books/NBK482299/
  • https://www.healthpages.org/health-a-z/understanding-the-5-ws-of-post-op-fever-and-its-variations/

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