# Cardiac Arrest Risk Triage (CART) CART Status: LIVE Price: $0.005 USDC `GET /api/calc/cart` HTML: https://magentlab.com/docs/cart Markdown: https://magentlab.com/docs/cart.md Not a medical device. Not a diagnosis, dose, or listing recommendation. ## What it computes Compute the Churpek 2012 Cardiac Arrest Risk Triage (CART) integer score from caller-assigned maximum respiratory rate, maximum heart rate, minimum diastolic blood pressure, and age. ## When to use When an agent needs the published Churpek 2012 Table 3 CART point total and must not invent a cardiac-arrest diagnosis, RRT order, or risk-band percents. ## When not to use - Not a medical device and not a cardiac-arrest diagnosis, RRT activation, or code-blue order. magent does not measure vitals; the caller assigns maximum RR, maximum HR, minimum DBP, and age. - Churpek 2012 Table 3 integer CART (beta x 9) only. Score range 0-57. Does not return risk-band percents or a three-band enum. - The paper's operational cut-off for comparison with MEWS is not emitted as a required band or RRT threshold. - This is not MEWS. Related MEWS is a different published score. ## Formula ``` CART = rr_points + hr_points + dbp_points + age_points; Churpek 2012 Table 3 integer score (beta x 9); max 57 ``` ## Citation [Derivation of a Cardiac Arrest Prediction Model Using Ward Vital Signs](https://doi.org/10.1097/CCM.0b013e318250aa5a) Churpek MM, Yuen TC, Park SY, Meltzer DO, Hall JB, Edelson DP Crit Care Med. 2012;40(7):2102-2108 DOI: [10.1097/CCM.0b013e318250aa5a](https://doi.org/10.1097/CCM.0b013e318250aa5a) ## Worked example ### RR 20, HR 80, DBP 80, age 40 Given: `age=40, diastolic_mm_hg=80, heart_rate_bpm=80, respiratory_rate=20` 1. RR 20 → 0; HR 80 → 0; DBP 80 → 0; age 40 → 0 2. Score = 0 (max 57) ### Highest Table 3 bands Given: `age=70, diastolic_mm_hg=34, heart_rate_bpm=140, respiratory_rate=30` 1. RR 30 → 22; HR 140 → 13; DBP 34 → 13; age 70 → 9 2. Score = 57 (max 57) ## Also searched as - cardiac arrest risk triage - CART score - CART - Churpek CART - ward vital signs cardiac arrest - cardiac arrest triage score ## Parameters - `respiratory_rate` (integer, required): Maximum respiratory rate in breaths/min (integer 0-80). Churpek 2012 Table 3: <21 → 0, 21-23 → 8, 24-25 → 12, 26-29 → 15, >29 → 22. magent does not measure vitals; the caller assigns the number. - `heart_rate_bpm` (integer, required): Maximum heart rate in beats/min (integer 30-220). Churpek 2012 Table 3: <110 → 0, 110-139 → 4, >139 → 13. magent does not measure vitals; the caller assigns the number. - `diastolic_mm_hg` (integer, required): Minimum diastolic blood pressure in mm Hg (integer 20-160). Churpek 2012 Table 3: >49 → 0, 40-49 → 4, 35-39 → 6, <35 → 13. magent does not measure vitals; the caller assigns the number. - `age` (integer, required): Age in years (integer 18-120). Churpek 2012 Table 3: <55 → 0, 55-69 → 4, >69 → 9. magent does not assign age. ## 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. Method: `POST /api/calc/cart` Max items: 25 Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic) Status: 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: ```json { "items": [ { "age": "40", "diastolic_mm_hg": "80", "heart_rate_bpm": "80", "respiratory_rate": "20" }, { "age": "40", "diastolic_mm_hg": "80", "heart_rate_bpm": "80", "respiratory_rate": "20" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/cart Example 200: ```json { "count": 2, "path": "/api/calc/cart", "items": [ { "components": [ { "value": 20, "factor": "respiratory_rate", "points": 0, "present": false }, { "value": 80, "factor": "heart_rate_bpm", "points": 0, "present": false }, { "value": 80, "factor": "diastolic_mm_hg", "points": 0, "present": false }, { "value": 40, "factor": "age", "points": 0, "present": false } ], "age": 40, "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": "Churpek MM, Yuen TC, Park SY, Meltzer DO, Hall JB, Edelson DP", "doi": "10.1097/CCM.0b013e318250aa5a", "id": "churpek-2012", "pmid": "22584764", "source": "Crit Care Med. 2012;40(7):2102-2108", "title": "Derivation of a Cardiac Arrest Prediction Model Using Ward Vital Signs" }, "formula": "cart", "formula_expression": "CART = rr_points + hr_points + dbp_points + age_points; Churpek 2012 Table 3 integer score (beta x 9); max 57", "max_score": 57, "score": 0, "diastolic_mm_hg": 80, "heart_rate_bpm": 80, "respiratory_rate": 20 }, { "components": [ { "value": 20, "factor": "respiratory_rate", "points": 0, "present": false }, { "value": 80, "factor": "heart_rate_bpm", "points": 0, "present": false }, { "value": 80, "factor": "diastolic_mm_hg", "points": 0, "present": false }, { "value": 40, "factor": "age", "points": 0, "present": false } ], "age": 40, "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": "Churpek MM, Yuen TC, Park SY, Meltzer DO, Hall JB, Edelson DP", "doi": "10.1097/CCM.0b013e318250aa5a", "id": "churpek-2012", "pmid": "22584764", "source": "Crit Care Med. 2012;40(7):2102-2108", "title": "Derivation of a Cardiac Arrest Prediction Model Using Ward Vital Signs" }, "formula": "cart", "formula_expression": "CART = rr_points + hr_points + dbp_points + age_points; Churpek 2012 Table 3 integer score (beta x 9); max 57", "max_score": 57, "score": 0, "diastolic_mm_hg": 80, "heart_rate_bpm": 80, "respiratory_rate": 20 } ] } ``` ## Response fields - `formula` (string): cart - `formula_expression` (string): Exact expression used - `score` (integer): CART points 0-57 - `max_score` (integer): Always 57 (22+13+13+9) - `respiratory_rate` (integer): Maximum respiratory rate used, breaths/min - `heart_rate_bpm` (integer): Maximum heart rate used, bpm - `diastolic_mm_hg` (integer): Minimum diastolic BP used, mm Hg - `age` (integer): Age in years used - `components` (array): Per-vital and age points - `citation` (object): Churpek 2012 Crit Care Med citation - `disclaimer` (string): Not-a-device notice ## Example JSON Frozen fixture. Not a live lookup. ```json { "components": [ { "value": 20, "factor": "respiratory_rate", "points": 0, "present": false }, { "value": 80, "factor": "heart_rate_bpm", "points": 0, "present": false }, { "value": 80, "factor": "diastolic_mm_hg", "points": 0, "present": false }, { "value": 40, "factor": "age", "points": 0, "present": false } ], "age": 40, "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": "Churpek MM, Yuen TC, Park SY, Meltzer DO, Hall JB, Edelson DP", "doi": "10.1097/CCM.0b013e318250aa5a", "id": "churpek-2012", "pmid": "22584764", "source": "Crit Care Med. 2012;40(7):2102-2108", "title": "Derivation of a Cardiac Arrest Prediction Model Using Ward Vital Signs" }, "formula": "cart", "formula_expression": "CART = rr_points + hr_points + dbp_points + age_points; Churpek 2012 Table 3 integer score (beta x 9); max 57", "max_score": 57, "score": 0, "diastolic_mm_hg": 80, "heart_rate_bpm": 80, "respiratory_rate": 20 } ``` ## Errors - HTTP 400 `invalid_rts_respiratory_rate`: respiratory_rate must be an integer from 0 to 80. Returned before settlement; you are not charged. - HTTP 400 `invalid_heart_rate`: heart_rate_bpm must be an integer from 30 to 220 Returned before settlement; you are not charged. - HTTP 400 `invalid_diastolic_bp`: diastolic_mm_hg must be a number from 20 to 160. Returned before settlement; you are not charged. - HTTP 400 `invalid_age`: age must be an integer from 18 to 120 Returned before settlement; you are not charged. - HTTP 400 `invalid_cart`: each CART 2012 vital or age must be a published Table 3 category. Returned before settlement; you are not charged. - HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged. - HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged. - HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged. Shared HTTP 402 and 503: https://magentlab.com/docs/payments ## Related tools - [MEWS](https://magentlab.com/docs/mews) — Compute the Subbe 2001 modified Early Warning Score from systolic BP, heart rate, respiratory rate, temperature, and caller-assigned AVPU. ## 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. - GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall). - HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote. - Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering. - Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional. - Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402. - offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront. - offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization. - not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search. Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers). Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments Stdio MCP (one process per host): https://magentlab.com/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.