# Rapid shallow breathing index (RSBI) Rapid shallow breathing index Status: LIVE Price: $0.005 USDC `GET /api/calc/rsbi` HTML: https://magentlab.com/docs/rsbi Markdown: https://magentlab.com/docs/rsbi.md Not a medical device. Not a diagnosis, dose, or listing recommendation. ## What it computes Compute the Yang and Tobin rapid shallow breathing index as respiratory rate in breaths/min divided by tidal volume in liters. ## When to use When an agent needs f/VT with VT in liters and must not invent a wean order or perform an SBT. ## When not to use - Not a wean order and not a diagnosis. - Measured during spontaneous breathing as published (Yang and Tobin 1991). - Not a ventilator-derived index unless the caller supplies frequency (f) and tidal volume (VT). - Magent does not perform a spontaneous breathing trial (SBT). ## Formula ``` rsbi = respiratory_rate / tidal_volume_l ``` ## Citation [A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation](https://doi.org/10.1056/NEJM199105233242101) Yang KL, Tobin MJ N Engl J Med. 1991;324(21):1445-1450 DOI: [10.1056/NEJM199105233242101](https://doi.org/10.1056/NEJM199105233242101) ## Worked example ### RR 20, VT 400 mL Given: `respiratory_rate=20, tidal_volume_ml=400` 1. tidal_volume_l = 400 / 1000 = 0.4 2. rsbi = 20 / 0.4 = 50.0 ### RR 21, VT 0.2 L Given: `respiratory_rate=21, tidal_volume_l=0.2` 1. rsbi = 21 / 0.2 = 105.0 2. 105.0 is not greater than 105 ## Also searched as - RSBI - rapid shallow breathing index - Yang Tobin index - f/VT - frequency over tidal volume - Tobin RSBI - rapid shallow breathing - breaths per minute per liter ## Parameters - `respiratory_rate` (integer, required): Respiratory rate in breaths/min (integer 4-80). - `tidal_volume_ml` (number, optional): Tidal volume in milliliters (50-2000). Converted as tidal_volume_l = tidal_volume_ml / 1000. Provide this or tidal_volume_l, not both. - `tidal_volume_l` (number, optional): Tidal volume in liters (0.05-2.0). Yang and Tobin RSBI uses VT in liters. Provide this or tidal_volume_ml, not both. ## Bulk (POST) POST the same path with a JSON items array. Price is n times the GET unit. Invalid items return HTTP 400 before settlement. Method: `POST /api/calc/rsbi` Max items: 25 Price: unit_amount * n (unit 5000 atomic) Status: PREVIEW - 1 to 25 items. Each item uses the same keys as the GET query parameters. - 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": [ { "respiratory_rate": "20", "tidal_volume_ml": "400" }, { "respiratory_rate": "20", "tidal_volume_ml": "400" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/rsbi Example 200: ```json { "count": 2, "path": "/api/calc/rsbi", "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": "Yang KL, Tobin MJ", "doi": "10.1056/NEJM199105233242101", "id": "yang-tobin-1991", "source": "N Engl J Med. 1991;324(21):1445-1450", "title": "A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation" }, "formula": "rsbi", "formula_expression": "rsbi = respiratory_rate / tidal_volume_l", "respiratory_rate": 20, "rsbi": 50.0, "rsbi_gt_105": false, "tidal_volume_l": 0.4 }, { "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": "Yang KL, Tobin MJ", "doi": "10.1056/NEJM199105233242101", "id": "yang-tobin-1991", "source": "N Engl J Med. 1991;324(21):1445-1450", "title": "A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation" }, "formula": "rsbi", "formula_expression": "rsbi = respiratory_rate / tidal_volume_l", "respiratory_rate": 20, "rsbi": 50.0, "rsbi_gt_105": false, "tidal_volume_l": 0.4 } ] } ``` ## Response fields - `formula` (string): rsbi - `formula_expression` (string): Exact expression used - `respiratory_rate` (integer): Respiratory rate used, breaths/min - `tidal_volume_l` (number): Tidal volume used, liters (ml inputs converted / 1000) - `rsbi` (number): Respiratory rate divided by tidal volume in liters, 1 decimal - `rsbi_gt_105` (boolean): True when rounded RSBI is greater than 105 breaths/min/L - `citation` (object): Yang and Tobin 1991 citation - `disclaimer` (string): Not-a-device notice ## Example JSON Frozen fixture. Not a live lookup. ```json { "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": "Yang KL, Tobin MJ", "doi": "10.1056/NEJM199105233242101", "id": "yang-tobin-1991", "source": "N Engl J Med. 1991;324(21):1445-1450", "title": "A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation" }, "formula": "rsbi", "formula_expression": "rsbi = respiratory_rate / tidal_volume_l", "respiratory_rate": 20, "rsbi": 50.0, "rsbi_gt_105": false, "tidal_volume_l": 0.4 } ``` ## Errors - HTTP 400 `invalid_respiratory_rate`: respiratory_rate must be an integer from 4 to 80. Returned before settlement; you are not charged. - HTTP 400 `invalid_tidal_volume`: tidal_volume_ml (50-2000) or tidal_volume_l (0.05-2.0) is required, not both. 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 - [Oxygenation index](https://magentlab.com/docs/oxygenation-index) — Compute the oxygenation index from inspired oxygen fraction, mean airway pressure in cm H2O, and arterial PO2. - [PaO2/FiO2 ratio](https://magentlab.com/docs/pf-ratio) — Compute the PaO2/FiO2 ratio as arterial PO2 in mm Hg divided by inspired oxygen fraction. ## Payment Required query parameters must be present and valid. 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 EIP-3009 (scheme exact, assetTransferMethod eip3009) with validBefore = now + accepts[0].maxTimeoutSeconds (600 seconds). That window starts when you sign and must cover wallet confirmation plus CDP verify and settle. Magent retries transient facilitator 429/5xx before answering. Do not send upto or batch-settlement payloads; magent does not offer those schemes. - Retry the same URL with PAYMENT-SIGNATURE (base64 JSON echoing accepted, payload, and extensions when present). - Success is HTTP 200 JSON plus PAYMENT-RESPONSE. Settlement happens before the tool runs. HTTP 503 settlement_uncertain or settle_failed: retry the same PAYMENT-SIGNATURE. Mint a new 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. - 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. - not offered `batch-settlement`: Not offered. Payment-channel vouchers claimed later in batches. Not the same as POST {items} bulk (that is still exact). Same-path POST {items} is still scheme exact: one EIP-3009 authorization for n times the GET unit. 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 - Invalid query parameters return HTTP 400 before settlement. You are not charged. - Settlement finishes before the tool executes (paymentFlow upfront). 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.