Vitals API - Scalpal

All responses are JSON unless noted. Values only appear as numbers when Presage marks them stable; otherwise they’re null.

Method	Route	Returns
GET	`/vitals`	The latest snapshot
GET	`/vitals/stream`	The same snapshot as server-sent events, about 10 a second
POST	`/baseline/capture`	Freezes the baseline from the last 12 s of stable readings (median)
GET	`/baseline`	The current baseline
GET	`/monitor`	OR monitor values: baseline plus the simulated change
GET	`/preview.jpg`	One JPEG from the configured camera, no quota. `409` while a live session holds the camera
GET	`/health`	Mode and status

Snapshot

{
  "schema": "scalpal.vitals/0",
  "mode": "live",
  "label": "Volunteer · real vitals · Presage",
  "status": { "ok": true, "code": 0, "reason": "Measuring" },
  "pulse": { "bpm": 85.3, "confidence": 97.7 },
  "breathing": { "bpm": 17.6, "confidence": 72.0, "heldMs": 4000 },
  "measuring": { "pulse": false, "breathing": true },
  "traces": { "pulse": [[77660000, 0.17]], "breathing": [[77660000, -0.41]] },
  "cameraBusy": true,
  "updatedAt": 1791093163288
}

mode is demo or live. Demo payloads are always labeled.
heldMs means the reading dipped below Presage’s stable threshold and this is the last stable value, that many milliseconds old. It’s held for up to 10 s, then becomes null.
traces are [timestamp in microseconds, value] pairs.
status.reason carries Presage’s hint when it isn’t measuring, like Move down, or tilt the camera up.

Baseline

{ "hr": 85, "rr": 18, "sys": 118, "dia": 76, "source": "measured" }

source is measured (live), demo, or authored when there weren’t enough stable readings. Blood pressure always comes from the authored baseline, since Presage doesn’t measure it here.

Monitor

GET /monitor?bloodLostMl=1000&bleedMlPerMin=200&weightKg=70

Parameter	Default	Meaning
`bloodLostMl`	0	Blood lost so far
`bleedMlPerMin`	0	Current uncontrolled bleeding rate
`weightKg`	70	Chart weight, for estimated blood volume
`critical`	off	`1` adds an acute spike

{
  "hr": 110, "rr": 25, "sys": 116, "dia": 78,
  "hemorrhageClass": 2, "bloodLossPct": 22.4,
  "baseline": { "hr": 85, "rr": 18, "source": "measured" },
  "label": "HR 110 · simulated from baseline 85 (measured)",
  "simulated": true, "mode": "live"
}