Haldane's decompression model

Haldane's decompression model is a mathematical model that describes the process of decompression in scuba diving. It was developed by the British scientist John Scott Haldane in the early 20th century.

History

Haldane's decompression model was first proposed in 1908. Haldane was a physiologist who had been studying the effects of high pressure on the human body. He was commissioned by the Royal Navy to develop a safe method for divers to ascend from deep dives without suffering from decompression sickness, also known as "the bends".

Principles

Haldane's model is based on the concept of tissue compartments, which represent groups of tissues in the body with similar rates of gas absorption and elimination. Each compartment is assumed to be homogeneously perfused, and the rate of gas uptake and elimination is assumed to be proportional to the difference in partial pressures in the gas in the lung and the tissue.

Haldane introduced the concept of "half-times" to describe the rate at which tissues absorb and eliminate gas. A tissue with a short half-time will absorb and eliminate gas quickly, while a tissue with a long half-time will do so more slowly.

Haldane also proposed the concept of "supersaturation", which is the state in which a tissue contains more gas than it would at equilibrium with the current ambient pressure. Haldane's model assumes that a certain level of supersaturation is tolerable without causing decompression sickness.

Limitations and modifications

While Haldane's decompression model was a significant advancement in diving safety, it has some limitations. It does not account for the effect of exercise, temperature, or the aging process on decompression. It also assumes a linear relationship between pressure and gas uptake/elimination, which is not accurate at high pressures.

Over the years, many modifications have been made to Haldane's model to improve its accuracy. These include the Bühlmann model, which introduces different allowable supersaturation levels for different tissues, and the Varying Permeability Model, which accounts for the non-linear relationship between pressure and gas uptake/elimination.

See also

• Decompression practice
• Decompression theory
• Decompression (diving)