Emergency · LIVE

Pediatric NEXUS II

Apply the Gupta 2018 Pediatric NEXUS II seven-criterion decision instrument and return whether the child is low-risk (all seven caller-assigned flags false). Age 0-17 is required but is not a score criterion. CT may be omitted by this instrument when low-risk. Does not order a CT.

LIVE $0.005 USDC GET /api/calc/pediatric_nexus_ii

Markdown: /docs/pediatric-nexus-ii.md · Canonical: https://magentlab.com/docs/pediatric-nexus-ii

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

What it computes

Apply the Gupta 2018 Pediatric NEXUS II seven-criterion decision instrument and return whether the child is low-risk (all seven caller-assigned flags false). Age 0-17 is required but is not a score criterion. CT may be omitted by this instrument when low-risk. Does not order a CT.

When to use

When an agent has caller-assigned findings after blunt head trauma in a child (age 0-17) and needs the published Pediatric NEXUS II decision instrument, not Mower 2017 adult NEXUS Head CT, not PECARN, CATCH, or CHALICE, and not Hoffman 2000 NEXUS C-spine.

When not to use

• Not a medical device. Not a diagnosis. magent does not examine the patient.
• Not a CT order. Low-risk means CT may be omitted by this instrument. Presence of a criterion does not mandate CT. Do not order a CT from this tool.
• Not adult NEXUS Head CT. This tool is the Gupta 2018 seven-criterion Pediatric NEXUS II instrument, not the Mower 2017 adult eight-criterion NEXUS Head CT, not PECARN, CATCH, or CHALICE, and not Hoffman 2000 NEXUS C-spine.
• Age 0-17 is required but is not a criterion: it matches the Gupta 2018 pediatric population and is not scored. Adult NEXUS Head CT age ≥ 65 is dropped. The seven clinical flags determine low_risk.

Formula

low_risk iff no skull_fracture and no scalp_hematoma and no neurologic_deficit and no altered_alertness and no abnormal_behavior and no persistent_vomiting and no coagulopathy

Citation

Title

Validation of the Pediatric NEXUS II Head Computed Tomography Decision Instrument for Selective Imaging of Pediatric Patients with Blunt Head Trauma.

Authors

Gupta M, Mower WR, Rodriguez RM, Hendey GW

Source

Acad Emerg Med. 2018;25(7):729-737

DOI

10.1111/acem.13431

Worked example

Also searched as

• Pediatric NEXUS II
• Gupta Pediatric NEXUS II
• Pediatric NEXUS II Head CT
• NEXUS II pediatric head CT
• Gupta 2018 Pediatric NEXUS II
• pediatric blunt head trauma CT rule
• seven-criterion Pediatric NEXUS II
• Pediatric NEXUS II decision instrument

Try

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

/api/calc/pediatric_nexus_ii?age=10&skull_fracture=false&scalp_hematoma=false&neurologic_deficit=false&altered_alertness=false&abnormal_behavior=false&persistent_vomiting=false&coagulopathy=false

Full URL: https://api.magentlab.com/api/calc/pediatric_nexus_ii?age=10&skull_fracture=false&scalp_hematoma=false&neurologic_deficit=false&altered_alertness=false&abnormal_behavior=false&persistent_vomiting=false&coagulopathy=false

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/pediatric_nexus_ii?age=10&skull_fracture=false&scalp_hematoma=false&neurologic_deficit=false&altered_alertness=false&abnormal_behavior=false&persistent_vomiting=false&coagulopathy=false"

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/pediatric_nexus_ii 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": [
    {
      "abnormal_behavior": "false",
      "age": "10",
      "altered_alertness": "false",
      "coagulopathy": "false",
      "neurologic_deficit": "false",
      "persistent_vomiting": "false",
      "scalp_hematoma": "false",
      "skull_fracture": "false"
    },
    {
      "abnormal_behavior": "false",
      "age": "10",
      "altered_alertness": "false",
      "coagulopathy": "false",
      "neurologic_deficit": "false",
      "persistent_vomiting": "false",
      "scalp_hematoma": "false",
      "skull_fracture": "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/pediatric_nexus_ii",
  "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": "Gupta M, Mower WR, Rodriguez RM, Hendey GW",
        "doi": "10.1111/acem.13431",
        "id": "gupta-2018",
        "pmid": "29665151",
        "source": "Acad Emerg Med. 2018;25(7):729-737",
        "title": "Validation of the Pediatric NEXUS II Head Computed Tomography Decision Instrument for Selective Imaging of Pediatric Patients with Blunt Head Trauma."
      },
      "formula": "pediatric_nexus_ii",
      "formula_expression": "low_risk iff no skull_fracture and no scalp_hematoma and no neurologic_deficit and no altered_alertness and no abnormal_behavior and no persistent_vomiting and no coagulopathy",
      "age_years": 10,
      "criteria": [
        {
          "factor": "no_skull_fracture",
          "met": true
        },
        {
          "factor": "no_scalp_hematoma",
          "met": true
        },
        {
          "factor": "no_neurologic_deficit",
          "met": true
        },
        {
          "factor": "no_altered_alertness",
          "met": true
        },
        {
          "factor": "no_abnormal_behavior",
          "met": true
        },
        {
          "factor": "no_persistent_vomiting",
          "met": true
        },
        {
          "factor": "no_coagulopathy",
          "met": true
        }
      ],
      "low_risk": 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": "Gupta M, Mower WR, Rodriguez RM, Hendey GW",
        "doi": "10.1111/acem.13431",
        "id": "gupta-2018",
        "pmid": "29665151",
        "source": "Acad Emerg Med. 2018;25(7):729-737",
        "title": "Validation of the Pediatric NEXUS II Head Computed Tomography Decision Instrument for Selective Imaging of Pediatric Patients with Blunt Head Trauma."
      },
      "formula": "pediatric_nexus_ii",
      "formula_expression": "low_risk iff no skull_fracture and no scalp_hematoma and no neurologic_deficit and no altered_alertness and no abnormal_behavior and no persistent_vomiting and no coagulopathy",
      "age_years": 10,
      "criteria": [
        {
          "factor": "no_skull_fracture",
          "met": true
        },
        {
          "factor": "no_scalp_hematoma",
          "met": true
        },
        {
          "factor": "no_neurologic_deficit",
          "met": true
        },
        {
          "factor": "no_altered_alertness",
          "met": true
        },
        {
          "factor": "no_abnormal_behavior",
          "met": true
        },
        {
          "factor": "no_persistent_vomiting",
          "met": true
        },
        {
          "factor": "no_coagulopathy",
          "met": true
        }
      ],
      "low_risk": true
    }
  ]
}

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": "Gupta M, Mower WR, Rodriguez RM, Hendey GW",
    "doi": "10.1111/acem.13431",
    "id": "gupta-2018",
    "pmid": "29665151",
    "source": "Acad Emerg Med. 2018;25(7):729-737",
    "title": "Validation of the Pediatric NEXUS II Head Computed Tomography Decision Instrument for Selective Imaging of Pediatric Patients with Blunt Head Trauma."
  },
  "formula": "pediatric_nexus_ii",
  "formula_expression": "low_risk iff no skull_fracture and no scalp_hematoma and no neurologic_deficit and no altered_alertness and no abnormal_behavior and no persistent_vomiting and no coagulopathy",
  "age_years": 10,
  "criteria": [
    {
      "factor": "no_skull_fracture",
      "met": true
    },
    {
      "factor": "no_scalp_hematoma",
      "met": true
    },
    {
      "factor": "no_neurologic_deficit",
      "met": true
    },
    {
      "factor": "no_altered_alertness",
      "met": true
    },
    {
      "factor": "no_abnormal_behavior",
      "met": true
    },
    {
      "factor": "no_persistent_vomiting",
      "met": true
    },
    {
      "factor": "no_coagulopathy",
      "met": true
    }
  ],
  "low_risk": true
}

Client errors (HTTP 400)

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

Related tools

• NEXUS Head CT — Apply the Mower 2017 NEXUS Head CT eight-criterion decision instrument and return whether the patient is low-risk (all eight caller-assigned criteria absent). CT may be omitted by this instrument when low-risk. Does not order a CT.
• PECARN pediatric head CT — Apply the Kuppermann 2009 PECARN prediction trees and return high, intermediate, or low risk of clinically important brain injury from caller-assigned findings after pediatric head trauma.
• CATCH — Apply the Osmond 2010 CATCH derivation and return high, medium, or low risk plus whether CT of the head is indicated from seven caller-assigned findings after pediatric minor head injury.
• CHALICE — Apply the Dunning 2006 CHALICE rule and return whether CT is required from caller-assigned history, examination, and mechanism findings after head injury in a child younger than 16.

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.