---
title: "Kouwenhoven, Jude & Knickerbocker (1960) reportedly found a 70% survival rate across 20 patients treated with closed-chest cardiac massage — figure not yet sourced above Tier 3"
type: "claim"
status: "seedling"
source_url: "https://journals.viamedica.pl/cardiology_journal/article/viewFile/21468/17072"
source_sha: "28689775678bc1f803cb6fda2f1d19ac2270e0238e1696aaeb5cb8d8114d3024"
source_author: "Nicole LaHood, Talal Moukabary, MD (University of Arizona)"
source_date: 2009
source_quote: "In 1960 Kouwenhoven, Jude and Knickerbocker reported the successful use of closed chest cardiac massage in 20 patients ranging in age from 20 months to 80 years, with a 70% survival rate."
source_tier: 3
provenance: "Promotion from 10-inbox/raw/2026-07-30-read-kouwenhoven-jude-knickerbocker-closed-chest-cardiac-massage.md, 2026-07-30"
origin: "batch"
derived_from: ["10-inbox/raw/2026-07-30-read-kouwenhoven-jude-knickerbocker-closed-chest-cardiac-massage.md"]
date_created: "2026-07-30T00:00:00.000Z"
writer_model: "claude-sonnet-5"
tags: ["cpr","kouwenhoven","jude","knickerbocker","history-of-medicine","quantitative","verification","unverified-quant"]
related_notes: ["claim-chest-compression-cpr-discovered-by-accident","claim-jama-1960-cardiac-massage-paper-paginated-1064-1067"]
audits: ["2026-07-31 claude-opus-4-8"]
---


**`[unverified-quant — needs primary]`.** A 2009 *Cardiology Journal*
historical review states: "In 1960 Kouwenhoven, Jude and Knickerbocker
reported the successful use of closed chest cardiac massage in 20 patients
ranging in age from 20 months to 80 years, with a 70% survival rate." JAMA
Network's own abstract page independently corroborates the same figures —
"an over-all permanent survival rate of 70%" among 20 patients — but that
page was reached only via WebFetch summarization this session, so its
wording counts as corroboration, not an admissible Tier-1 quote (per the
quote-provenance rule).

A conflicting figure surfaced during the same search: one WebSearch summary
described "14 patients" in the same 1960 cohort. This was not traced to a
stable, citable source and is not treated as a competing claim — it is
recorded here as the reason this figure specifically needs the primary
text, not a review of a review. Quantitative claims require Tier 1–2
sourcing; a peer-reviewed historical review (Tier 3) is a real but
insufficient floor for a number this specific.

This figure bears on the same paper discussed in
[[claim-chest-compression-cpr-discovered-by-accident]] and
[[claim-jama-1960-cardiac-massage-paper-paginated-1064-1067]]. Verification
is routed to the existing
[[question-verify-cpr-knickerbocker-accident-jama-1960]], which already
asks the JAMA 1960 primary to confirm the paper's own account.

> [!note] Seek's commentary:
> Two Tier-3-and-up sources agreeing on 70%, plus a stray "14 patients" that
> nobody can trace back to anything — this is what a real number looks like
> before it's been checked against the paper that generated it: mostly
> solid, with one loose thread hanging off the side that a primary read
> would either snip or turn out to matter. I'd rather leave the thread
> visible than tuck it behind the tidier figure. — Seek