# Fincke 2004 Cardiac Power Output (CPO) Calculator > Fincke 2004 Cardiac Power Output (CPO) Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14). Calculates cardiac power output in watts using the Fincke 2004 formula (CPO = MAP × CO / 451) and returns the result with ROC-based risk band classification. ## Facts - Endpoint: GET https://api.magentlab.com/api/calc/cpo - Price: $0.005/call - Payment: x402 - Status: unknown - Last checked: 2026-09-14 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/fincke-2004-cardiac-power-output-cpo-calculator-d2d9253e - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_YIwMQIFhshDMwVjb4EJiC Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently. ## How to call it through Zero Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`): ```sh zero fetch --capability fincke-2004-cardiac-power-output-cpo-calculator-d2d9253e ``` Example prompt: Calculate cardiac power output using the Fincke 2004 formula for a patient with a mean arterial pressure of 75 mm Hg and a cardiac output of 4.2 L/min, and tell me which ROC risk band they fall into. ## When to prefer this Choose this endpoint when you need to apply the exact Fincke 2004 CPO formula (MAP × CO / 451) and receive the published ROC-based risk band classification. Prefer this over manual calculation when precision to two decimal places and correct boundary handling (<=0.53 equality case) are required. Use it when MAP has already been computed externally (e.g. from /api/calc/map) since this endpoint does not accept SBP/DBP inputs. Not suitable for computing cardiac power index (body surface area-indexed values) or for diagnostic or treatment decisions. ## Known failure modes - map_mm_hg outside 30–180 range returns a validation error - cardiac_output_l_min outside 0.5–20 range returns a validation error - missing required query parameters returns a 400-level error - payment not included or insufficient USDC results in x402 payment required response ## How this service works Fincke 2004 cardiac power output from MAP (mm Hg) and cardiac output (L/min): CPO = MAP × CO / 451. Returns cpo_watts to two decimals and the paper ROC band (<=0.53 or >0.53) from the unrounded value. Equality at 0.53 W is <=0.53. MAP is caller-supplied (Fincke used diastolic + (systolic−diastolic)/3); this tool does not take SBP/DBP or compute cardiac power index. Not a medical device, shock diagnosis, or treatment target. ## Output Returns cpo_watts (a number rounded to two decimal places representing cardiac power output in watts) and the Fincke 2004 ROC band classification — either '<=0.53' or '>0.53' — derived from the unrounded CPO value. Values exactly equal to 0.53 W are classified as <=0.53. ## Request schema (JSON Schema) ```json { "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "input" ], "properties": { "input": { "type": "object", "required": [ "type", "method" ], "properties": { "type": { "type": "string", "const": "http" }, "method": { "enum": [ "GET", "HEAD", "DELETE" ], "type": "string" }, "headers": { "type": "object", "additionalProperties": { "type": "string" } }, "queryParams": { "type": "object", "required": [ "map_mm_hg", "cardiac_output_l_min" ], "properties": { "map_mm_hg": { "type": "number", "description": "Mean arterial pressure in mm Hg (30-180). Fincke 2004 used diastolic + (systolic−diastolic)/3. Callers may send MAP from /api/calc/map; this tool does not take SBP or DBP." }, "cardiac_output_l_min": { "type": "number", "description": "Cardiac output in L/min (0.5-20). Not indexed to body surface area." } } } }, "additionalProperties": false }, "output": { "type": "object", "required": [ "type" ], "properties": { "type": { "type": "string" }, "example": { "type": "object" } } } } } ``` ## Response schema (JSON Schema) ```json { "type": "json", "example": { "path": "/api/calc/cpo", "count": 2, "items": [ { "band": ">0.53", "formula": "cpo", "citation": { "id": "fincke-2004", "doi": "10.1016/j.jacc.2004.03.060", "pmid": "15261929", "title": "Cardiac power is the strongest hemodynamic correlate of mortality in cardiogenic shock: a report from the SHOCK trial registry", "source": "J Am Coll Cardiol. 2004;44(2):340-348", "authors": "Fincke R, Hochman JS, Lowe AM, et al." }, "cpo_watts": 1, "map_mm_hg": 90, "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "formula_expression": "cpo_watts = map_mm_hg * cardiac_output_l_min / 451", "cardiac_output_l_min": 5 }, { "band": ">0.53", "formula": "cpo", "citation": { "id": "fincke-2004", "doi": "10.1016/j.jacc.2004.03.060", "pmid": "15261929", "title": "Cardiac power is the strongest hemodynamic correlate of mortality in cardiogenic shock: a report from the SHOCK trial registry", "source": "J Am Coll Cardiol. 2004;44(2):340-348", "authors": "Fincke R, Hochman JS, Lowe AM, et al." }, "cpo_watts": 1, "map_mm_hg": 90, "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "formula_expression": "cpo_watts = map_mm_hg * cardiac_output_l_min / 451", "cardiac_output_l_min": 5 } ] } } ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fincke-2004-cardiac-power-output-cpo-calculator-d2d9253e/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)