What tools do we have to assess risk?

Can we be more precise in defining risk for patients?

So, in an ideal world, a risk prediction tool would allow the Perioperative Care Team to calculate a patient’s risk of death and major complication rates accurately – long before the surgical team operate. After all, as you have learned, it is all about risk, conveying risk and accepting/not-accepting risk – so we need to use some figures to help our patients decide.

Read the following list of characteristics we think makes up a good risk prediction tool. It should:

• Be easy to perform
• Use readily available data
• Be unambiguous
• Predict with a good degree of certainty what percentage risk the patient has for morbidity and mortality
• Be validated in the population of interest, for example, UK patients undergoing colorectal surgery.

Let’s get a feel for what things increase the patient risk of complications and death and have a closer look at the risk prediction tools available.

SORT Score

The SORT tool. (Image source)

• This is the Surgical Outcome Risk Tool
• It incorporates the type of surgery, ASA score, surgical urgency, patient age, the presence or absence of cancer and the clinician’s own risk assessment.
• It estimates the risk of inpatient death within 30 days.

Question: Was the predicted risk higher or lower than you expected?

And now to another example of a risk assessment scoring system….

NSQIP Score:

The ACS NSQIP Surgical Risk Calculator. (Image source)

• Includes information such as procedure, age, sex, respiratory problems, dialysis, BMI and smoking history.
• The calculator gives a complex risk assessment, but clearly presented, with risk of multiple factors including death at 30 days, pulmonary complications, functional decline and severe complications. It then plots the patients risk against an average risk for that procedure.
• A useful function is that it presents the risk of being discharged to a rehabilitation hospital or nursing home. For many patients, this is a more tangible and often proportionally much greater than the risk of death. We should be consenting patients with information which includes all their risks, which is why many prefer the ACS NSQIP tool for discussing risk with patients.

For the same patient as before, input their details into the ACS NSQIP tool. Is the risk significantly different? Do you like the way that the data is presented here? Think about how easy or difficult it would be to show the risk screen to a patient and their loved ones to discuss risk.

Cardiopulmonary Exercise Testing (CPET)

In recent years many hospitals now offer a Cardio-Pulmonary Exercise Test (CPET). It is a measure of the patient’s fitness and has been used to assess risk and as a prediction tool regarding death and morbidity.

As you will see from this short explanatory video, it is an exercise test where the function of the heart and lungs is monitored closely to identify how efficiently they deliver oxygen to the tissues and, importantly, how much reserve function a patient has.

While not as simple as a risk-calculator tool, it is still relatively easy to perform, can be completed in less than an hour and, despite how it might appear, is well tolerated by the patient and is a safe test to perform for almost all surgical patients.

Dr Rob Stephens talking about CPET.

And now see a test in action – just to understand what some of your patients may experience on the road to surgery (many thanks to the staff at Southampton University Hospital for making this video publicly available).

CPET: Cardio-Pulmonary Exercise Testing. (Video source)

So we have established that a patient’s suitability for POCU has everything to do with reducing their risk of poor outcomes. We have explored briefly the risks our surgical patients are exposed to, which are dependent on multiple factors. We also looked at how to estimate risk using validated tools that are crucial in not only securing the right postoperative setting for our patients, but also in communicating with them and their families.

But, hang on…

What about the type of surgery – surely an aortic aneurysm repair carries more risk of death than varicose veins surgery?

Well spotted, we should not forget about the impact of surgery on a patient’s outcomes and you will have spotted that in the risk-prediction tools one must enter the type of operation the patient is having for that very reason – Minor, Intermediate, Major, Major complex is how we define our surgeries. See this graphic below to appreciate some patient groups.