ARISCAT is a point-based method for organizing information about the risk of pulmonary complications after surgery. This calculator adds seven patient and procedure factors, then displays a risk group and the percentage associated with that group in this implementation. It can help a clinician check the arithmetic behind a preoperative assessment.
The result is not a determination that an operation is safe or unsafe. It also does not predict a particular complication for an individual. A useful assessment requires accurate preoperative information, the planned procedure and clinical judgment about whether the original method fits the patient and setting. The source study is linked below so the population, outcomes and method can be checked.
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How to Use This Calculator
Review all seven selections rather than accepting the defaults. Several Yes options may already be selected when the page opens, so an untouched form does not represent a patient with no risk factors.
Select the appropriate age band and preoperative oxygen-saturation band. Use a documented preoperative measurement and clarify any boundary value or measurement condition with the treating team.
Enter the recent respiratory-infection and anemia findings. The anemia criterion shown is hemoglobin at or below 10 g/dL; it is a threshold question, rather than a request to type a laboratory number.
Confirm incision category, anticipated surgical duration and emergency status from the actual plan. Choose Calculate, then review the point total before interpreting its category.
If the plan or measurements change, calculate again and keep the date and assumptions with the result. Do not use a hypothetical favorable answer to replace an unknown clinical finding.
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Formula Used
ARISCAT total = age points + SpO₂ points + recent infection points + anemia points + incision points + duration points + emergency points. This page groups totals as less than 26, 26–44, or at least 45.
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Variables Explained
Item
Meaning
Age
The three age categories contribute 0, 3 or 16 points in ascending order. Confirm exact boundary wording against the published method.
Preoperative SpO₂
The three oxygen-saturation categories contribute 0, 8 or 24 points. Saturation is a percentage, not an oxygen flow rate.
Recent infection and anemia
A respiratory infection in the last month contributes 17 points; the selected anemia criterion contributes 11 points. No contributes zero for each.
Incision
Peripheral, upper abdominal and intrathoracic selections contribute 0, 15 and 24 points respectively.
Duration and emergency status
The duration bands contribute 0, 16 or 23 points. An emergency procedure adds 8 points; a nonemergency procedure adds zero.
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Worked Example
Consider an illustrative patient aged 65, with preoperative SpO₂ of 94%, no respiratory infection in the preceding month and no qualifying anemia. Suppose the planned procedure is upper abdominal, expected to last 2–3 hours, and is not an emergency. The page adds 3 + 8 + 0 + 0 + 15 + 16 + 0 = 42 points.
A total of 42 falls into this calculator’s intermediate group, which displays 13.3%. If the same example were an emergency, the extra 8 points would make the total 50 and move it into the high group. This illustrates a threshold change in the model; it does not show that one change causes a particular patient’s risk to jump by a precisely known amount.
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Why Use This Calculator?
The display maps a score below 26 to low risk and 1.6%, 26–44 to intermediate risk and 13.3%, and 45 or more to high risk and 42.1%. These are group estimates used by the page. They should not be read as a personalized probability precise to one decimal place.
The outcome is a composite of postoperative pulmonary complications, rather than mortality alone or pneumonia alone. The page’s description includes respiratory failure, infection, pleural effusion, atelectasis, pneumothorax, bronchospasm and aspiration pneumonitis. A clinician may need additional assessments that address other surgical risks. The score does not prescribe an anesthetic technique, determine the best operation or replace discussion of benefits, alternatives and recovery planning.
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Common Mistakes
Do not confuse hemoglobin units: 10 g/dL is 100 g/L. Match the stated threshold instead of comparing a raw laboratory number with an incompatible unit.
Do not enter a postoperative oxygen measurement as though it were the specified preoperative value.
The current form’s shorthand boundary labels can be ambiguous at exact age or saturation cutoffs. Check the published scoring definition instead of guessing a neighboring category.
Do not treat an empty or default answer as a confirmed negative finding. Missing information can materially change a point total.
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Frequently Asked Questions
Does a low ARISCAT score rule out complications?
No. The low group still has a nonzero displayed estimate, and a group-based model cannot account for every individual circumstance. It organizes selected factors; it does not establish that a complication cannot occur.
Is the percentage a prediction of death?
No. This page describes a composite pulmonary-complication outcome. A mortality prediction would require a method specifically developed for that endpoint, with a defined population and follow-up period.
Can I use the score to decide whether to cancel surgery?
A score alone cannot make that decision. The treating team needs to weigh the indication, urgency, alternatives, clinical findings and the patient’s preferences. Use the calculation to support questions about the assessment, rather than to make an independent treatment decision.
Why can two clinicians obtain different scores?
They may be using different planned durations, incision classifications, measurements or versions of the assessment. Compare each selected factor and its point contribution first. A difference in input definition can matter more than the arithmetic.
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