Chest-compression CPR was discovered by accident: a defibrillator paddle's weight alone raised a dog's blood pressure before any current flowed

Closed-chest cardiac massage — the manual chest-compression technique underlying essentially all modern CPR — was not designed but noticed. In the late 1950s, while testing a closed-chest defibrillator prototype on a dog, graduate student Guy Knickerbocker, working in William Kouwenhoven's Johns Hopkins program (claim-kouwenhoven-electrocution-research-produced-defibrillator), per NIST "noticed that the weight of the paddles alone pressing on the dog's chest increased its blood pressure" — a circulatory effect produced by mechanical pressure before any current was applied. That incidental observation redirected the team toward rhythmic manual compression of the chest, published as W. B. Kouwenhoven, J. R. Jude, and G. G. Knickerbocker, "Closed-Chest Cardiac Massage," JAMA 173:1064–1067 (1960) — the paper underlying modern CPR practice.

The discovery-by-accident structure is the reversal at the heart of the story: a life-support technique nearly every adult is trained in was found inside an experiment designed to test something else, buried in the physical fact of a chest under paddle weight. It is the terminal hop of a lineage that began with the telephone/power industry's electric-shock-injury research (claim-bstj-1936-published-electric-shock-heart-paper).

Unverified against the primary. The narrative rests on NIST's Tier-2 account. The JAMA 1960 paper itself was not read at capture, and the specific quantitative and mechanistic details — the exact blood-pressure change Knickerbocker measured, and the claim that compression restored "roughly half of normal circulation" — carry a [unverified-quant/mechanism — needs primary] flag inherited from the capture. Verification is routed to question-verify-cpr-knickerbocker-accident-jama-1960; this note stays seedling until the primary confirms the figures.

Correction 2026-07-30: the citation pagination above was wrong in the original promotion — corrected from 173:94–97 to 173:1064–1067, confirmed Tier 1 against PubMed's own catalog record and JAMA Network's own article page. See claim-jama-1960-cardiac-massage-paper-paginated-1064-1067 for the correction's own sourcing. Separately, a 2026-07-30 verification capture surfaced Guy Knickerbocker's own first-person account of this discovery, which describes a materially different physical circumstance than the paddle-weight narrative this note rests on — see claim-knickerbockers-own-account-conflicts-with-nist-paddle-weight-mechanism. This note's [unverified-quant/mechanism — needs primary] flag stands; if anything, it is now better evidenced as unresolved, not less.