CAHP score (Maupain 2016)

CAHP

Sum Maupain 2016 Figure 2 CAHP nomogram integer points from age, arrest location, initial rhythm, no-flow, low-flow, epinephrine tertile, and arterial pH, and return Table 3 low/medium/high strata.

LIVE $0.005 USDC GET /api/calc/cahp

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

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

What it computes

Sum Maupain 2016 Figure 2 CAHP nomogram integer points from age, arrest location, initial rhythm, no-flow, low-flow, epinephrine tertile, and arterial pH, and return Table 3 low/medium/high strata.

When to use

When an agent needs the published CAHP nomogram total after OHCA and must not invent a withdrawal-of-care order, extra mortality labels, or an epinephrine scale other than Table 2 tertiles.

When not to use

Not a medical device and not a diagnosis or withdrawal-of-care order.
magent does not measure pH, collapse-to-BLS time, BLS-to-ROSC time, or epinephrine dose; those values and arrest location and initial rhythm are caller-assigned.
Table 3 strata are low <150, medium 150-200, and high >200. The abstract also prints ≤150 / ≥200; 150 and 200 are medium.
Figure 2B prints 88% poor outcome at total 177. This tool returns that printed percent only at 177 and does not invent other mortality labels.
Epinephrine uses Table 2 tertiles (0 / 1-2 / ≥3 mg). Age, no-flow, low-flow, and pH follow the Figure 2 caption integers with linear nomogram ticks; values beyond age 10-100, no-flow 0-30 min, low-flow 0-60 min, and pH 6.5-7.5 use those truncated ends.

Formula

CAHP = round(1.1*(age-10)) + 25 if arrest_at_home + 27 if not shockable_rhythm + round(2.8*no_flow_min) + round(0.8*low_flow_min) + epinephrine mg (0 → 0; 1-2 → 27; ≥3 → 43) + round(585-77*arterial_ph); Maupain 2016 Figure 2 nomogram integer points (caption: age 30 → 22, home → 25, non-shockable → 27, no-flow 5 min → 14, low-flow 10 min → 8, epinephrine 3 mg → 43, pH 7.10 → 38, total 177 → 88%); Table 3 low <150, medium 150-200, high >200 (150 and 200 are medium); max 411

Citation

Title: The CAHP (Cardiac Arrest Hospital Prognosis) score: a tool for risk stratification after out-of-hospital cardiac arrest
Authors: Maupain C, Bougouin W, Lamhaut L, et al.
Source: Eur Heart J. 2016;37(42):3222-3231
DOI: 10.1093/eurheartj/ehv556

Worked example

Figure 2 caption (score 177, medium, 88%)

Given: age=30arrest_at_home=truearterial_ph=7.10epinephrine_mg=3low_flow_min=10no_flow_min=5shockable_rhythm=false

Age 30 → 22; arrest at home → 25; non-shockable → 27; no-flow 5 min → 14; low-flow 10 min → 8; epinephrine 3 mg → 43; pH 7.10 → 38
Total 22+25+27+14+8+43+38 = 177 (max 411); Table 3 medium (150-200); Figure 2B poor-outcome 88%

Public shockable arrest, no epinephrine (score 30, low)

Given: age=30arrest_at_home=falsearterial_ph=7.50epinephrine_mg=0low_flow_min=0no_flow_min=0shockable_rhythm=true

Age 30 → 22; public → 0; shockable → 0; no-flow 0 → 0; low-flow 0 → 0; epinephrine 0 → 0; pH 7.50 → 8
Total 30 (max 411); Table 3 low (<150)

Also searched as

CAHP
CAHP score
Cardiac Arrest Hospital Prognosis
Maupain score
OHCA prognosis score
CAHP nomogram
cardiac arrest hospital prognosis score

Try

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

/api/calc/cahp?age=30&arrest_at_home=true&shockable_rhythm=false&no_flow_min=5&low_flow_min=10&epinephrine_mg=3&arterial_ph=7.10

Full URL: https://api.magentlab.com/api/calc/cahp?age=30&arrest_at_home=true&shockable_rhythm=false&no_flow_min=5&low_flow_min=10&epinephrine_mg=3&arterial_ph=7.10

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/cahp?age=30&arrest_at_home=true&shockable_rhythm=false&no_flow_min=5&low_flow_min=10&epinephrine_mg=3&arterial_ph=7.10"

Parameters

Name	Type	Required	Description
`age`	integer	required	Age in years (18-120). Figure 2 caption: 30 years → 22. Linear nomogram: round(1.1*(age-10)); truncated below 10 and above 100.
`arrest_at_home`	boolean	required	Cardiac arrest at home versus public, as assigned by the caller. true scores 25 (Figure 2 caption); false (public) scores 0.
`shockable_rhythm`	boolean	required	Initial shockable rhythm (VF or pulseless VT) as assigned by the caller. true scores 0; false (non-shockable) scores 27 (Figure 2 caption).
`no_flow_min`	integer	required	Collapse-to-BLS (no-flow) minutes (integer 0-90). Figure 2 caption: 5 min → 14. Linear nomogram: round(2.8*minutes); truncated above 30.
`low_flow_min`	integer	required	BLS-to-ROSC (low-flow) minutes (integer 0-180). Figure 2 caption: 10 min → 8. Linear nomogram: round(0.8*minutes); truncated above 60.
`epinephrine_mg`	integer	required	Total pre-ROSC epinephrine in mg (integer 0-30). Table 2 tertiles on the nomogram: 0 → 0; 1-2 → 27; ≥3 → 43 (Figure 2 caption 3 mg → 43).
`arterial_ph`	number	required	Admission arterial pH (6.5-7.8). Figure 2 caption: 7.10 → 38. Linear nomogram: round(585-77*pH); truncated to 6.5-7.5. magent does not measure pH.

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/cahp 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": [
    {
      "age": "30",
      "arrest_at_home": "true",
      "arterial_ph": "7.10",
      "epinephrine_mg": "3",
      "low_flow_min": "10",
      "no_flow_min": "5",
      "shockable_rhythm": "false"
    },
    {
      "age": "30",
      "arrest_at_home": "true",
      "arterial_ph": "7.10",
      "epinephrine_mg": "3",
      "low_flow_min": "10",
      "no_flow_min": "5",
      "shockable_rhythm": "false"
    }
  ]
}

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/cahp",
  "items": [
    {
      "components": [
        {
          "value": 30,
          "factor": "age",
          "points": 22,
          "present": true
        },
        {
          "factor": "arrest_at_home",
          "points": 25,
          "present": true
        },
        {
          "value": false,
          "factor": "shockable_rhythm",
          "points": 27,
          "present": true
        },
        {
          "value": 5,
          "factor": "no_flow_min",
          "points": 14,
          "present": true
        },
        {
          "value": 10,
          "factor": "low_flow_min",
          "points": 8,
          "present": true
        },
        {
          "value": 3,
          "factor": "epinephrine_mg",
          "points": 43,
          "present": true
        },
        {
          "value": 7.1,
          "factor": "arterial_ph",
          "points": 38,
          "present": true
        }
      ],
      "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": "Maupain C, Bougouin W, Lamhaut L, et al.",
        "doi": "10.1093/eurheartj/ehv556",
        "id": "maupain-2016-cahp",
        "pmid": "26497161",
        "source": "Eur Heart J. 2016;37(42):3222-3231",
        "title": "The CAHP (Cardiac Arrest Hospital Prognosis) score: a tool for risk stratification after out-of-hospital cardiac arrest"
      },
      "formula": "cahp",
      "formula_expression": "CAHP = round(1.1*(age-10)) + 25 if arrest_at_home + 27 if not shockable_rhythm + round(2.8*no_flow_min) + round(0.8*low_flow_min) + epinephrine mg (0 → 0; 1-2 → 27; ≥3 → 43) + round(585-77*arterial_ph); Maupain 2016 Figure 2 nomogram integer points (caption: age 30 → 22, home → 25, non-shockable → 27, no-flow 5 min → 14, low-flow 10 min → 8, epinephrine 3 mg → 43, pH 7.10 → 38, total 177 → 88%); Table 3 low <150, medium 150-200, high >200 (150 and 200 are medium); max 411",
      "max_score": 411,
      "score": 177,
      "age_years": 30,
      "cahp_risk": "medium",
      "arrest_at_home": true,
      "arterial_ph": 7.1,
      "epinephrine_mg": 3,
      "low_flow_min": 10,
      "no_flow_min": 5,
      "shockable_rhythm": false,
      "nomogram_poor_outcome_percent": 88
    },
    {
      "components": [
        {
          "value": 30,
          "factor": "age",
          "points": 22,
          "present": true
        },
        {
          "factor": "arrest_at_home",
          "points": 25,
          "present": true
        },
        {
          "value": false,
          "factor": "shockable_rhythm",
          "points": 27,
          "present": true
        },
        {
          "value": 5,
          "factor": "no_flow_min",
          "points": 14,
          "present": true
        },
        {
          "value": 10,
          "factor": "low_flow_min",
          "points": 8,
          "present": true
        },
        {
          "value": 3,
          "factor": "epinephrine_mg",
          "points": 43,
          "present": true
        },
        {
          "value": 7.1,
          "factor": "arterial_ph",
          "points": 38,
          "present": true
        }
      ],
      "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": "Maupain C, Bougouin W, Lamhaut L, et al.",
        "doi": "10.1093/eurheartj/ehv556",
        "id": "maupain-2016-cahp",
        "pmid": "26497161",
        "source": "Eur Heart J. 2016;37(42):3222-3231",
        "title": "The CAHP (Cardiac Arrest Hospital Prognosis) score: a tool for risk stratification after out-of-hospital cardiac arrest"
      },
      "formula": "cahp",
      "formula_expression": "CAHP = round(1.1*(age-10)) + 25 if arrest_at_home + 27 if not shockable_rhythm + round(2.8*no_flow_min) + round(0.8*low_flow_min) + epinephrine mg (0 → 0; 1-2 → 27; ≥3 → 43) + round(585-77*arterial_ph); Maupain 2016 Figure 2 nomogram integer points (caption: age 30 → 22, home → 25, non-shockable → 27, no-flow 5 min → 14, low-flow 10 min → 8, epinephrine 3 mg → 43, pH 7.10 → 38, total 177 → 88%); Table 3 low <150, medium 150-200, high >200 (150 and 200 are medium); max 411",
      "max_score": 411,
      "score": 177,
      "age_years": 30,
      "cahp_risk": "medium",
      "arrest_at_home": true,
      "arterial_ph": 7.1,
      "epinephrine_mg": 3,
      "low_flow_min": 10,
      "no_flow_min": 5,
      "shockable_rhythm": false,
      "nomogram_poor_outcome_percent": 88
    }
  ]
}

Response

Field	Type	Description
`formula`	string	cahp
`formula_expression`	string	Exact expression used
`score`	integer	Figure 2 nomogram integer total
`max_score`	integer	411
`cahp_risk`	string	Table 3 stratum: low if score <150, medium if 150-200, high if >200. 150 and 200 are medium.
`nomogram_poor_outcome_percent`	integer	Figure 2B printed poor-outcome percent when the total is 177 (88). Omitted for other totals.
`age_years`	integer	Age used
`arrest_at_home`	boolean	Caller-assigned arrest at home
`shockable_rhythm`	boolean	Caller-assigned initial shockable rhythm
`no_flow_min`	integer	No-flow minutes used
`low_flow_min`	integer	Low-flow minutes used
`epinephrine_mg`	integer	Epinephrine mg used
`arterial_ph`	number	Arterial pH used
`components`	array	Per-factor Figure 2 points
`citation`	object	Maupain et al. Eur Heart J 2016 citation
`disclaimer`	string	Not-a-device notice

Example JSON

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

{
  "components": [
    {
      "value": 30,
      "factor": "age",
      "points": 22,
      "present": true
    },
    {
      "factor": "arrest_at_home",
      "points": 25,
      "present": true
    },
    {
      "value": false,
      "factor": "shockable_rhythm",
      "points": 27,
      "present": true
    },
    {
      "value": 5,
      "factor": "no_flow_min",
      "points": 14,
      "present": true
    },
    {
      "value": 10,
      "factor": "low_flow_min",
      "points": 8,
      "present": true
    },
    {
      "value": 3,
      "factor": "epinephrine_mg",
      "points": 43,
      "present": true
    },
    {
      "value": 7.1,
      "factor": "arterial_ph",
      "points": 38,
      "present": true
    }
  ],
  "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": "Maupain C, Bougouin W, Lamhaut L, et al.",
    "doi": "10.1093/eurheartj/ehv556",
    "id": "maupain-2016-cahp",
    "pmid": "26497161",
    "source": "Eur Heart J. 2016;37(42):3222-3231",
    "title": "The CAHP (Cardiac Arrest Hospital Prognosis) score: a tool for risk stratification after out-of-hospital cardiac arrest"
  },
  "formula": "cahp",
  "formula_expression": "CAHP = round(1.1*(age-10)) + 25 if arrest_at_home + 27 if not shockable_rhythm + round(2.8*no_flow_min) + round(0.8*low_flow_min) + epinephrine mg (0 → 0; 1-2 → 27; ≥3 → 43) + round(585-77*arterial_ph); Maupain 2016 Figure 2 nomogram integer points (caption: age 30 → 22, home → 25, non-shockable → 27, no-flow 5 min → 14, low-flow 10 min → 8, epinephrine 3 mg → 43, pH 7.10 → 38, total 177 → 88%); Table 3 low <150, medium 150-200, high >200 (150 and 200 are medium); max 411",
  "max_score": 411,
  "score": 177,
  "age_years": 30,
  "cahp_risk": "medium",
  "arrest_at_home": true,
  "arterial_ph": 7.1,
  "epinephrine_mg": 3,
  "low_flow_min": 10,
  "no_flow_min": 5,
  "shockable_rhythm": false,
  "nomogram_poor_outcome_percent": 88
}

Client errors (HTTP 400)

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

HTTP	Code	When
400	`invalid_cahp`	CAHP inputs must match Maupain 2016 age, arrest location, initial rhythm, no-flow and low-flow times, epinephrine dose, and arterial pH. Returned before settlement; you are not charged.
400	`invalid_items`	POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
400	`invalid_item_count`	items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
400	`invalid_item`	each items entry must be a JSON object Returned before settlement; you are not charged.

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qSOFA — Compute the Sepsis-3 qSOFA score from respiratory rate, caller-assigned altered mentation, and systolic blood pressure.

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.