How does iron lung end

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Last updated: April 8, 2026

Quick Answer: The iron lung era effectively ended in the late 1950s and early 1960s with the widespread adoption of polio vaccines. The Salk vaccine (inactivated polio vaccine) was introduced in 1955, followed by the Sabin vaccine (oral polio vaccine) in 1961, which dramatically reduced polio cases. By the 1970s, mechanical ventilators replaced iron lungs for most respiratory support needs, though a few patients continued using them into the 21st century. The last known U.S. iron lung user, Martha Lillard, still relied on one as of 2023.

Key Facts

The Salk inactivated polio vaccine was introduced in 1955
The Sabin oral polio vaccine was introduced in 1961
Polio cases in the U.S. dropped from 58,000 in 1952 to under 1,000 by 1962
Mechanical ventilators largely replaced iron lungs by the 1970s
Martha Lillard was still using an iron lung as of 2023

Overview

The iron lung, formally known as the Drinker respirator, was invented in 1927 by Philip Drinker and Louis Shaw at Harvard University to treat respiratory failure caused by polio. During the polio epidemics of the 1940s and 1950s, iron lungs became essential medical devices, with over 1,200 in use in the United States at the peak of the 1952 epidemic. These negative pressure ventilators encased patients' bodies (except their heads) in airtight metal cylinders, using alternating pressure to assist breathing when polio paralyzed chest muscles. The most severe polio epidemics occurred between 1947 and 1955, with the U.S. experiencing 58,000 cases in 1952 alone, creating urgent demand for respiratory support devices.

How It Works

The iron lung operates on negative pressure ventilation principles. A patient lies inside a cylindrical metal tank with their head protruding through a sealed collar. A pump mechanism rhythmically decreases and increases air pressure inside the chamber. When pressure decreases below atmospheric level, the patient's chest expands, drawing air into the lungs through normal breathing pathways. When pressure increases, the chest compresses, forcing exhalation. This mimics natural breathing mechanics without requiring active muscle contraction. Early models used hand-operated bellows, while later versions featured electric pumps. The device could maintain breathing indefinitely for patients with paralyzed respiratory muscles, though it limited mobility and required constant monitoring for proper seal maintenance and pressure regulation.

Why It Matters

The iron lung's significance extends beyond its medical function to symbolize both polio's devastating impact and medical innovation's triumph. It saved thousands of lives during polio epidemics when no alternatives existed for respiratory support. The device's eventual obsolescence following vaccine development demonstrates public health's power—polio vaccines reduced global cases from 350,000 annually in 1988 to just 6 reported wild cases in 2021. The transition to modern positive pressure ventilators in the 1970s marked critical advances in portable respiratory care technology. Today, iron lungs serve as historical artifacts reminding us of epidemic challenges and medical progress, while their few remaining users highlight long-term polio survivor experiences.