# Parkland crystalloid volume

Parkland formula

## Also searched as

- Parkland formula
- burn crystalloid volume
- 4 mL kg TBSA
- Baxter Parkland
- 24 hour burn fluids
- first 8 hours Parkland
- TBSA fluid resuscitation

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/parkland`
HTML: https://magentlab.com/docs/parkland
Markdown: https://magentlab.com/docs/parkland.md

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

## What it computes

Compute adult Parkland 24-hour crystalloid volume from weight and percent TBSA, with half allotted to the first 8 hours from the time of burn.

## When to use

When an agent needs the adult Parkland 4 mL/kg/%TBSA 24-hour crystalloid split and must not invent a burn-fluid volume or apply modified Brooke (2 mL) or pediatric Galveston formulas.

## When not to use

- Adult 4 mL/kg/%TBSA Parkland crystalloid only. Does not implement modified Brooke (2 mL) or pediatric Galveston formulas.
- Not a treatment order or IV prescription. magent does not titrate to urine output or choose fluid type.
- The first 8 hours are counted from the time of burn, not from arrival. This tool does not take elapsed time since injury.

## Formula

```
volume_24h_ml = 4 * weight_kg * tbsa_percent; first_8h_ml = volume_24h_ml / 2; remaining_16h_ml = volume_24h_ml / 2
```

## Citation

[Fluid volume and electrolyte changes of the early postburn period](https://doi.org/10.1016/S0094-1298(20)30126-7)
Baxter CR
Clin Plast Surg. 1974;1(4):693-703
DOI: [10.1016/S0094-1298(20)30126-7](https://doi.org/10.1016/S0094-1298(20)30126-7)

## Worked example

### 70 kg, 50% TBSA

Given: `tbsa_percent=50, weight_kg=70`

1. volume_24h_ml = 4 × 70 × 50 = 14000.0 mL
2. first_8h_ml = 14000.0 / 2 = 7000.0 mL (from time of burn, not arrival)
3. remaining_16h_ml = 14000.0 / 2 = 7000.0 mL


## Parameters

- `weight_kg` (number, optional): Weight in kilograms. Provide weight_kg or weight_lb.
- `weight_lb` (number, optional): Weight in pounds. Converted as kg = lb * 0.45359237.
- `tbsa_percent` (number, required): Percent total body surface area burned (1-100). 0 is invalid.

## 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/parkland`
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": [
    {
      "tbsa_percent": "50",
      "weight_kg": "70"
    },
    {
      "tbsa_percent": "50",
      "weight_kg": "70"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/parkland

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/parkland",
  "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": "Baxter CR",
        "doi": "10.1016/S0094-1298(20)30126-7",
        "id": "baxter-1974",
        "source": "Clin Plast Surg. 1974;1(4):693-703",
        "title": "Fluid volume and electrolyte changes of the early postburn period"
      },
      "formula": "parkland",
      "formula_expression": "volume_24h_ml = 4 * weight_kg * tbsa_percent; first_8h_ml = volume_24h_ml / 2; remaining_16h_ml = volume_24h_ml / 2",
      "weight_kg": 70.0,
      "first_8h_ml": 7.0e3,
      "remaining_16h_ml": 7.0e3,
      "tbsa_percent": 50.0,
      "volume_24h_ml": 1.4e4
    },
    {
      "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": "Baxter CR",
        "doi": "10.1016/S0094-1298(20)30126-7",
        "id": "baxter-1974",
        "source": "Clin Plast Surg. 1974;1(4):693-703",
        "title": "Fluid volume and electrolyte changes of the early postburn period"
      },
      "formula": "parkland",
      "formula_expression": "volume_24h_ml = 4 * weight_kg * tbsa_percent; first_8h_ml = volume_24h_ml / 2; remaining_16h_ml = volume_24h_ml / 2",
      "weight_kg": 70.0,
      "first_8h_ml": 7.0e3,
      "remaining_16h_ml": 7.0e3,
      "tbsa_percent": 50.0,
      "volume_24h_ml": 1.4e4
    }
  ]
}
```

## Response fields

- `formula` (string): parkland
- `formula_expression` (string): Exact expression used
- `weight_kg` (number): Normalized weight in kg
- `tbsa_percent` (number): Percent TBSA used (1-100)
- `volume_24h_ml` (number): Adult Parkland 24-hour crystalloid in mL, 1 decimal
- `first_8h_ml` (number): Half of volume_24h_ml for the first 8 hours from the time of burn, 1 decimal
- `remaining_16h_ml` (number): Half of volume_24h_ml for the remaining 16 hours, 1 decimal
- `citation` (object): Baxter Clin Plast Surg 1974 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": "Baxter CR",
    "doi": "10.1016/S0094-1298(20)30126-7",
    "id": "baxter-1974",
    "source": "Clin Plast Surg. 1974;1(4):693-703",
    "title": "Fluid volume and electrolyte changes of the early postburn period"
  },
  "formula": "parkland",
  "formula_expression": "volume_24h_ml = 4 * weight_kg * tbsa_percent; first_8h_ml = volume_24h_ml / 2; remaining_16h_ml = volume_24h_ml / 2",
  "weight_kg": 70.0,
  "first_8h_ml": 7.0e3,
  "remaining_16h_ml": 7.0e3,
  "tbsa_percent": 50.0,
  "volume_24h_ml": 1.4e4
}
```

## Errors

- HTTP 400 `invalid_weight`: weight_kg (1-500) or weight_lb (2-1100) is required Returned before settlement; you are not charged.
- HTTP 400 `invalid_tbsa_percent`: tbsa_percent must be a number from 1 to 100. 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

- [Maintenance fluids](https://magentlab.com/docs/maintenance-fluids) — Compute Holliday–Segar 1957 daily maintenance water from weight, plus the corresponding hourly milliliters.

## 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.