## **Core Concept**
Reactionary haemorrhage, also known as immediate or primary haemorrhage, occurs shortly after surgery. It is typically due to inadequate **hemostasis** (control of bleeding) during or immediately after the surgical procedure. This type of bleeding is often related to **surgical site** issues.

## **Why the Correct Answer is Right**
The correct timeframe for reactionary haemorrhage is within **24 hours** after surgery, but more specifically, it usually occurs within the first **few hours** post-operatively. This timeframe allows for the identification of issues related to the surgical technique, **coagulopathy**, or dislodgment of initial clots. Effective **hemostasis** is crucial during and after surgery to prevent such complications.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because reactionary haemorrhage does not occur immediately within seconds to minutes after surgery; that would be considered an **intraoperative** complication.
- **Option B:** This option suggests a timeframe that might be too long for what is typically classified as reactionary haemorrhage, which usually presents much sooner.
- **Option D:** This option suggests a timeframe that is longer than the typical presentation of reactionary haemorrhage.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that reactionary haemorrhage often relates to the **surgical technique** or **patient factors** such as coagulopathy. Monitoring patients closely for signs of bleeding in the immediate post-operative period is crucial. A classic clinical correlation is that patients on **anticoagulation therapy** are at higher risk for reactionary haemorrhage.

## **Correct Answer:** . 24 hours.