Neurology · LIVE

Cerebral perfusion pressure

CPP

Compute cerebral perfusion pressure as MAP minus ICP in mm Hg and flag whether CPP is at least 70 mm Hg per Rosner 1995.

LIVE $0.005 USDC GET /api/calc/cpp

Markdown: /docs/cpp.md · Canonical: https://magentlab.com/docs/cpp

Not a medical device. Not a diagnosis, dose, or listing recommendation.

What it computes

Compute cerebral perfusion pressure as MAP minus ICP in mm Hg and flag whether CPP is at least 70 mm Hg per Rosner 1995.

When to use

When an agent has caller-supplied MAP and ICP in mm Hg and needs the published CPP identity and the Rosner 1995 minimum-CPP-of-70 flag, not a monitor reading or a treatment order.

When not to use

• Not a medical device. Not a treatment protocol.
• map_mm_hg and icp_mm_hg are caller-supplied. magent does not measure MAP or ICP and is not an invasive monitor.
• cpp_ge_70 is the Rosner 1995 protocol minimum CPP of at least 70 mm Hg. It is not a later target.
• CPP may be negative when ICP exceeds MAP. That is not a validation error.

Formula

cpp_mm_hg = map_mm_hg - icp_mm_hg

Citation

Title

Cerebral perfusion pressure: management protocol and clinical results

Authors

Rosner MJ, Rosner SD, Johnson AH

Source

J Neurosurg. 1995;83(6):949-962

DOI

10.3171/jns.1995.83.6.0949

Worked example

Also searched as

• cerebral perfusion pressure
• CPP
• MAP minus ICP
• cerebral perfusion
• Rosner CPP
• intracranial pressure CPP
• CPP mm Hg

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/cpp?map_mm_hg=90&icp_mm_hg=10

Full URL: https://api.magentlab.com/api/calc/cpp?map_mm_hg=90&icp_mm_hg=10

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/cpp?map_mm_hg=90&icp_mm_hg=10"

Parameters

Bulk (POST)

POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement.

POST /api/calc/cpp Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 PREVIEW

• 1 to 25 items. Each item uses the same keys as the GET query parameters.
• POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows.
• The first invalid item fails the whole request (index in the 400 JSON). You are not charged.
• HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row.
• Catalog misses (empty matches, found=false) stay paid 200s inside that slot.
• x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items.

Example request (fixture)

{
  "items": [
    {
      "icp_mm_hg": "10",
      "map_mm_hg": "90"
    },
    {
      "icp_mm_hg": "10",
      "map_mm_hg": "90"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/cpp",
  "items": [
    {
      "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.",
      "citation": {
        "authors": "Rosner MJ, Rosner SD, Johnson AH",
        "doi": "10.3171/jns.1995.83.6.0949",
        "id": "rosner-1995",
        "pmid": "7490638",
        "source": "J Neurosurg. 1995;83(6):949-962",
        "title": "Cerebral perfusion pressure: management protocol and clinical results"
      },
      "formula": "cpp",
      "formula_expression": "cpp_mm_hg = map_mm_hg - icp_mm_hg",
      "map_mm_hg": 90.0,
      "cpp_ge_70": true,
      "cpp_mm_hg": 80.0,
      "icp_mm_hg": 10.0
    },
    {
      "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.",
      "citation": {
        "authors": "Rosner MJ, Rosner SD, Johnson AH",
        "doi": "10.3171/jns.1995.83.6.0949",
        "id": "rosner-1995",
        "pmid": "7490638",
        "source": "J Neurosurg. 1995;83(6):949-962",
        "title": "Cerebral perfusion pressure: management protocol and clinical results"
      },
      "formula": "cpp",
      "formula_expression": "cpp_mm_hg = map_mm_hg - icp_mm_hg",
      "map_mm_hg": 90.0,
      "cpp_ge_70": true,
      "cpp_mm_hg": 80.0,
      "icp_mm_hg": 10.0
    }
  ]
}

Response

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "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.",
  "citation": {
    "authors": "Rosner MJ, Rosner SD, Johnson AH",
    "doi": "10.3171/jns.1995.83.6.0949",
    "id": "rosner-1995",
    "pmid": "7490638",
    "source": "J Neurosurg. 1995;83(6):949-962",
    "title": "Cerebral perfusion pressure: management protocol and clinical results"
  },
  "formula": "cpp",
  "formula_expression": "cpp_mm_hg = map_mm_hg - icp_mm_hg",
  "map_mm_hg": 90.0,
  "cpp_ge_70": true,
  "cpp_mm_hg": 80.0,
  "icp_mm_hg": 10.0
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

Related tools

• Glasgow Coma Scale — Compute the Glasgow Coma Scale as the sum of caller-assigned eye, verbal, and motor integers. The 1974 or 1976 edition is required.

Payment

Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /docs/mcp.

Guarantees

• HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON.
• exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE.
• HTTP 402 is unpaid only. Do not sign a second authorization because of a 503.
• Execution is timeout-bounded and concurrency-capped.
• Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.