# Fick 1870 Cardiac Output Calculator

> Fick 1870 Cardiac Output 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).

Computes cardiac output (L/min) using the Fick 1870 formula from measured VO2, arterial oxygen content, and mixed-venous oxygen content

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/fick
- 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/fick-1870-cardiac-output-calculator-a9a97706
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_APm8FP7n3kOKfNPnOTks1

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 fick-1870-cardiac-output-calculator-a9a97706
```

Example prompt: Calculate cardiac output using the Fick 1870 formula: VO2 is 250 ml/min, arterial O2 content is 200 ml/L, and mixed-venous O2 content is 150 ml/L.

## When to prefer this

Use this endpoint when you have all three directly measured Fick terms (VO2, CaO2, CvO2) and need a strict 1870 Fick cardiac output computation without BSA estimation or Hüfner correction. Prefer this over general hemodynamic APIs when you need reproducible, formula-pure Fick results suitable for clinical documentation or research pipelines.

## Known failure modes

- CaO2 <= CvO2: request rejected because arteriovenous difference must be positive
- VO2 out of range (below 50 or above 2000 ml/min): clamped or rejected per magent validation
- CaO2 out of range (below 50 or above 400 ml/L equivalent): clamped or rejected
- CvO2 out of range (below 20 or above 350 ml/L equivalent): clamped or rejected
- Both ml/L and ml/dL variants supplied for the same parameter: rejected as ambiguous

## How this service works

Fick 1870 cardiac output: CO (L/min) = VO2 (ml/min) / (CaO2 - CvO2) with contents in ml/L (ml/dL x10). Caller supplies the three measured terms. Does not estimate VO2 from BSA or apply Hufner Hb factors. Rejects CaO2 <= CvO2. Not a catheter order, shock diagnosis, or medical device. magent does not sample blood.

## Output

Returns the calculated cardiac output in L/min computed as CO = VO2 / (CaO2 - CvO2), using inputs normalized to ml/L. Rejects requests where CaO2 is not greater than CvO2.

## 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": [
      "vo2_ml_min"
     ],
     "properties": {
      "cao2_ml_l": {
       "type": "number",
       "description": "Arterial oxygen content in ml/L (50-400, magent clamp). Provide this or cao2_ml_dl, not both. magent does not compute content from hemoglobin or Hüfner factors."
      },
      "cvo2_ml_l": {
       "type": "number",
       "description": "Mixed-venous oxygen content in ml/L (20-350, magent clamp). Provide this or cvo2_ml_dl, not both. Must be less than CaO2. magent does not sample mixed-venous blood."
      },
      "cao2_ml_dl": {
       "type": "number",
       "description": "Arterial oxygen content in ml/dL (5-40, magent clamp). Converted as ml/L = ml/dL × 10. Provide this or cao2_ml_l, not both."
      },
      "cvo2_ml_dl": {
       "type": "number",
       "description": "Mixed-venous oxygen content in ml/dL (2-35, magent clamp). Converted as ml/L = ml/dL × 10. Provide this or cvo2_ml_l, not both. Must be less than CaO2 after conversion."
      },
      "vo2_ml_min": {
       "type": "number",
       "description": "Measured oxygen consumption in ml/min (50-2000, magent clamp; Fick 1870 does not publish an input band). Caller supplies the measured term. magent does not estimate VO2 from BSA or assume 125 ml/min/m²."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fick-1870-cardiac-output-calculator-a9a97706/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)