How Saline Earned its Salt


The other day in Resus as I was putting up a bag of fluids for a patient I wondered how long it was we’d been using what seems an incredibly simple but important intervention for our patients. “Putting up a bag of fluids” is a core part of the resuscitation of an unwell patient to the extent it just rolls off the tongue.

Turns out the history of IV saline goes back to Victorian Britain and the cholera pandemics. The Industrial Revolution brought unprecedented numbers of people to the cities, especially London where the population trebled between 1815 and 1860. In many places sewage disposal was not much changed from Tudor days and so struggled to cope. By and large the response was simply to tip the waste into cesspits or into the nearest river hence ‘The Great Stink’ of 1858 which brought the city of London and even Parliament to a standstill.

These conditions were perfect for cholera, a disease brought to Britain from the Indian subcontinent in 1832. A secretory diarrhoea spread via the faeco-oral route it ‘enjoyed’ 5 pandemics between 1817 and 1896. Cholera presents with ‘rice water’ diarrhoea (up to a litre an hour) with a mortality rate up to 70% in untreated patients largely due to extreme dehydration.

Cholera challenged medics at the time and inspired some great work such as that of John Snow on Broad Street in 1854 who rejected the miasmic theory of spread and instead proposed there was a causative agent and that contaminated water was the source. In the same year the causative agent was identified by Filippo Pacini in Italy and was first grown in culture in 1884 by Robert Koch working in Egypt and India. Fluid replacement with intravenous fluid was another such innovation.

By 1832 the work of Dr W B O’Shaughnessy had concluded that the blood of cholera patients had lost most of its water as well as its saline contents and the Lancet recommended “the injection into the veins of tepid water, holding a solution of the normal salts of the blood.” That same year Thomas Latta, a physician working in Leith, Scotland attempted to treat a patient with cholera doing just this.

He first tried treating patients with fluids inserted rectally but found that not only did it not work it actually seemed to make their vomiting and diarrhoea worse. So then he tried intravenous injection. He wrote describing how over half an hour he injected 6 pints (3.4 litres) of fluid in the basilic vein of an elderly lady with cholera: “soon the sharpened features, and sunken eye, and fallen jaw, pale and cold, bearing the manifest imprint of death’s signet, began to glow with returning animation; the pulse returned to the wrist…” Sadly he left the patient in the hands of the house surgeon who did not repeat the treatment as the patient deteriorated again and so she died 5 hours later.

That same year Dr Robert Christison wrote to the Dutch government advising them on this new treatment. He described 37 cases treated with intravenous fluids of whom 12 survived. He mentioned certain risks including air embolus, phlebitis and the potential risks of introducing so much fluid to a patient but generally recommended the treatment. Looking back there were probably other risks too such as secondary infections from unsterile injections they wouldn’t have been aware of.

In these early days there was no standardisation of what the fluid should contain with some physicians using egg whites with their fluid and some adding albumin. It wasn’t until Dr Sydney Ringer’s work in the 1880s that an optimum physiological solution was found. The dangers of potential fluid overload were identified quite early on as well with S.K. Mujumbar of Port Blair, India writing in 1916 of the need to identify cholera patients who actually need fluids so as not to cause “an extra amount of work on the already weakened and embarrassed heart”.

0.9% Saline has since become a staple of modern medicine and is included on the World Health Organisation’s list of essential medicines last published in 2017.

Further pandemics of cholera occurred in 1899-1923 and 1961-1975 by which time advances in public health medicine meant Western Europe was unaffected. The last outbreak in the USA took place in 1910-1911. Cholera remains endemic in many countries in Africa and has continued to re-surface whenever sanitation is affected such as in Haiti following Hurricane Matthew. Diarrhoeal disease is the second highest cause of mortality and leading cause of malnutrition in the under-fives worldwide. The WHO describes diarrhoea as “preventable and treatable”. Re-hydration whether orally or intravenously remains the mainstay of treatment.

So whenever we are putting up a bag of fluid for a patient we are continuing a tradition first started by Thomas Latta injecting 6 pints of fluid into the basilic vein of his patient in Leith.

Thanks for reading

- Jamie