Practice tools

Numbers with context.
Decisions with a pathway.

Common calculations and research-linked discussion guides for anesthesia teams.

Reviewed by Justin Hefley · Approved October 18, 2026

Adult educational use; calculators do not provide surgical clearance or replace local policy. No patient identifiers are needed. Entries remain in this browser page, are not sent to the server, and are not saved by this site. Use Reset to clear them. No CE credit.

01 · Body size

Adult BMI

Weight divided by height squared, in kg/m². Categories are for adults age 20 and older. BMI is a screening measure; it does not distinguish muscle from fat and is not a dosing weight.

CDC adult BMI categories

Formula & input limits

BMI = kg ÷ m². Conversion: 1 lb = 0.45359237 kg; 1 inch = 2.54 cm. This tool accepts 20–500 kg and 80–250 cm (or their US-unit equivalents). These are input checks, not a clinical validation range. Categories use the unrounded result.

02 · Cardiac assessment

Revised Cardiac Risk Index

One point for each of six original predictors. Derived in adults age 50 or older undergoing elective major noncardiac surgery. Use the original definitions; this tool does not extend validation to emergency, cardiac, or younger populations.

MACE is an outcome, not a separate score. Major adverse cardiac events can have different definitions. The original RCRI endpoint included myocardial infarction, pulmonary edema, ventricular fibrillation or primary cardiac arrest, and complete heart block. It differs from 30-day death/MI/cardiac-arrest composites.

This calculator reports the score only. It does not assign a percentage or equate a score with the guideline’s ≥1% elevated-risk threshold. Risk assessment also needs the procedure, clinical status, functional capacity and a model with an appropriate endpoint.

Lee et al., original RCRI (1999) · 2024 AHA/ACC perioperative guideline · ACS NSQIP calculator (external)

The external ACS tool has its own inputs, terms, population and endpoints. Nothing entered here is transferred to it.

Original six predictors · answer every item High-risk surgeryOriginal definition: intraperitoneal, intrathoracic, or suprainguinal vascular surgery. This is not interchangeable with a modern procedure-specific risk category. History of ischemic heart diseaseHistory of MI, positive exercise test, current ischemic chest pain, nitrate therapy, or pathologic Q waves on ECG. Prior revascularization alone is not the original definition. History of congestive heart failureHistory of heart failure, pulmonary edema, paroxysmal nocturnal dyspnea, bilateral rales or S3, or chest radiograph with pulmonary vascular redistribution. History of cerebrovascular diseasePrior stroke or transient ischemic attack. Diabetes treated with insulinPreoperative insulin treatment; diabetes alone does not score this point. Preoperative serum creatinine >2.0 mg/dLStrictly greater than 2.0 mg/dL (176.8 µmol/L); eGFR is not a substitute for this original predictor.

Complete all six predictors.

03 · From the review

GLP-1: a screening conversation

An editorial discussion aid based on the 2024 multisociety guidance, linked to our GLP-1 evidence review. This proposed pathway has not been prospectively validated and does not estimate aspiration probability.

For patients taking a GLP-1 receptor agonist, document the drug, indication, dose, last dose and symptoms in the usual clinical record. Do not enter identifying information here. Unknown responses remain unresolved.

Screening prompts Urgent or emergency procedure?Urgency requires a separate immediate clinical assessment. Gastrointestinal symptoms?Nausea, vomiting, abdominal pain, dyspepsia or constipation. Characterize severity and persistence with the team. In dose escalation or recently increasing dose?Risk may differ during escalation compared with maintenance. Higher medication dose?Guidance identifies higher dose as a factor but supplies no universal drug-independent numeric cutoff. Confirm with the prescriber; do not guess. Weekly dosing formulation?Weekly formulations are identified as a risk factor in the guidance; this alone is not an instruction to withhold a dose. Other condition that may delay gastric emptying?For example gastroparesis, bowel dysmotility, or Parkinson disease.

Complete the screening questions.

Patient taking a GLP-1 medicine
Reconcile medication, symptoms and urgency

Urgent / emergency

Immediate anesthesia–procedural team assessment. Consider full-stomach precautions under ASA guidance. This route applies even if other answers are unknown.

Elective · escalation or symptoms

Discuss deferral until escalation has passed and symptoms have resolved, as described by ASA. Reassess with the responsible teams.

Other elevated-risk factor

Shared assessment. Consider diet modification, gastric ultrasound, and anesthetic-plan changes; discuss delay versus proceeding.

No elevated-risk factor identified

Continuation may be appropriate under the 2024 guidance. Confirm individualized fasting and glycemic instructions.

Any unknown answer

Clarify missing information. Do not treat it as “no.”

Which guidance is this?

The pathway follows the 2024 multisociety clinical practice guidance. It calls for shared decisions, recognizes limited evidence, and includes a liquid diet for at least 24 hours when delayed-emptying concern exists. ASA’s accompanying explanation supplies escalation/symptom deferral considerations; ASA’s patient guidance describes urgent-case full-stomach precautions. Medication withholding duration is uncertain. Ultrasound requires appropriate training and availability.

SPAQI’s 2025 consensus recommends different, broader fasting changes. These protocols should not be combined into one universal fasting instruction. The research review explains their differences and why ultrasound findings do not equal aspiration rates. Follow the chosen institutional protocol and the responsible clinical team.

Prepared October 18, 2026 · Anesthesiology.news editorial team · AI-assisted preparation · Reviewed by Justin Hefley · Approved October 18, 2026. Justin Hefley reports no disclosures.