What are PECARN Rules? Hint: They Don’t Involve Nuts

Deciding when to order a CT scan in the case of a head injury can be a frustrating process. Yes, the likelihood of a serious finding is often low, but do you really want to be wrong when it comes to a head injury? Absolutely not- the stakes are too high. In kids, the CT decision becomes an even riskier process. Ordering a CT scan unnecessarily increases risk of radiation-related malignancy later in life. Enter the PECARN rules. 

Fortunately, there is a highly reliable, easy to use algorithm that helps medical providers determine when a CT scan is necessary in pediatric head trauma. No more ordering head scans on a whim, the Pediatric Emergency Care Applied Research Network (PECARN), a hub of pediatric emergency medicine information, has developed a set of rules to follow in determining the necessity of CT scans in children under 15 years of age with head trauma. 

Why should nurse practitioners use an algorithm for imaging in pediatric head trauma?

Traumatic brain injury is a leading cause of death and disability in children worldwide resulting in more than 600,000 emergency department visits every year. Most of these head injuries are mild with just 10 percent of CT scans among kids with minor head trauma showing a traumatic brain injury. 50 percent of these children, however receive a head CT scan. 

Not only are unnecessary CT scans costly, they expose children to high amounts of radiation. It is estimated that the rate of lethal malignancy due to CT scans is between 1 in 1,000 and 1 in 5,000. Prevention of CT related malignancy is essential. Nurse practitioners must order these scans wisely, especially in kids. Using a set of standardized rules gives a reliable method for deciding which children require radiation-exposing CT scans and which do not. 

How are PECARN rules applied?

The first step in using the PECARN rules, is to evaluate the patient based on the Glascow Coma Scale (GCS) and assign a score. The PECARN rules apply only to patients with a GCS of 14 or higher. In general, if the child is awake, alert, and interactive, the GCS will be 14 or higher. 

Then, using the simple algorithm on MDCalc apply the PECARN head injury algorithm. The algorithm gives CT scan and observation recommendations based on information such as the patient’s age and mechanism of injury. 

If you prefer not to use an automated, online version of the rules, here’s a visual of the algorithm. 

How accurate is the PECARN algorithm?

The PECARN rules have a negative predictive value of 100% in children under 2 years of age and a negative predictive value of 98.4 to 99.95% in children greater than 2 years of age. This means that overall, kids identified as low risk on the PECARN algorithm are overwhelmingly correctly identified as not suffering from a traumatic brain injury. 

The PECARN rules also have a sensitivity of 100% for children under 2 years of age and a sensitivity of 94% to 96.8% for children greater than 2 years of age. This means that kids with a traumatic brain injury are also overwhelmingly correctly identified by the PECARN algorithm. 

The next time you treat a pediatric patient with a head injury, give the PECARN rules a try. They may help avoid an unnecessary CT scan and will also give you greater confidence in making your imaging decision. Parents will feel more at ease in your decision not to scan their child if you discuss with them the reliability of this set of rules along with radiation risks. 

Have you used the PECARN rules in your practice?


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