Last week, the Australian Therapeutic Goods Administration added intravenous (IV) fluids to the growing list of medicines in short supply. The shortage is due to higher-than-expected demand and manufacturing issues.

Two particular IV fluids are affected: saline and compound sodium lactate (also called Hartmann’s solution). Both fluids are made with salts.

There are IV fluids that use other components, such as sugar, rather than salt. But instead of switching patients to those fluids, the government has chosen to approve salt-based solutions by other overseas brands.

So why do IV fluids contain different chemicals? And why can’t they just be interchanged when one runs low?

We can’t just inject water into a vein

Drugs are always injected into veins in a water-based solution. But we can’t do this with pure water, we need to add other chemicals. That’s because of a scientific principle called osmosis.

Osmosis occurs when water moves rapidly in and out of the cells in the blood stream, in response to changes to the concentration of chemicals dissolved in the blood plasma. Think salts, sugars, nutrients, drugs and proteins.

Too high a concentration of chemicals and protein in your blood stream leads it to being in a “hypertonic” state, which causes your blood cells to shrink. Not enough chemicals and proteins in your blood stream causes your blood cells to expand. Just the right amount is called “isotonic”.

Mixing the drug with the right amount of chemicals, via an injection or infusion, ensures the concentration inside the syringe or IV bag remains close to isotonic.

What are the different types of IV fluids?

There are a range of IV fluids available to administer drugs. The two most popular are:

• 0.9% saline, which is an isotonic solution of table salt. This is one of the IV fluids in short supply
• a 5% solution of the sugar glucose/dextrose. This fluid is not in short supply.

There are also IV fluids that combine both saline and glucose, and IV fluids that have other salts:

• Ringer’s solution is an IV fluid which has sodium, potassium and calcium salts
• Plasma-Lyte has different sodium salts, as well as magnesium
• Hartmann’s solution (compound sodium lactate) contains a range of different salts. It is generally used to treat a condition called metabolic acidosis, where patients have increased acid in their blood stream. This is in short supply.

What if you use the wrong solution?

Some drugs are only stable in specific IV fluids, for instance, only in salt-based IV fluids or only in glucose.

Putting a drug into the wrong IV fluid can potentially cause the drug to “crash out” of the solution, meaning patients won’t get the full dose.

Or it could cause the drug to decompose: not only will it not work, but it could also cause serious side effects.

An example of where a drug can be transformed into something toxic is the cancer chemotherapy drug cisplatin. When administered in saline it is safe, but administration in pure glucose can cause life-threatening damage to a patients’ kidneys.

What can hospitals use instead?

The IV fluids in short supply are saline and Hartmann’s solution. They are provided by three approved Australian suppliers: Baxter Healthcare, B.Braun and Fresenius Kabi.

The government’s solution to this is to approve multiple overseas-registered alternative saline brands, which they are allowed to do under current legislation without it going through the normal Australian quality checks and approval process. They will have received approval in their country of manufacture.

The government is taking this approach because it may not be effective or safe to formulate medicines that are meant to be in saline into different IV fluids. And we don’t have sufficient capacity to manufacture saline IV fluids here in Australia.

The Australian Society of Hospital Pharmacists provides guidance to other health staff about what drugs have to go with which IV fluids in their Australian Injectable Drugs Handbook. If there is a shortage of saline or Hartmann’s solution, and shipments of other overseas brands have not arrived, this guidance can be used to select another appropriate IV fluid.

Why don’t we make it locally?

The current shortage of IV fluids is just another example of the problems Australia faces when it is almost completely reliant on its critical medicines from overseas manufacturers.

Fortunately, we have workarounds to address the current shortage. But Australia is likely to face ongoing shortages, not only for IV fluids but for any medicines that we rely on overseas manufacturers to produce. Shortages like this put Australian lives at risk.

In the past both myself, and others, have called for the federal government to develop or back the development of medicines manufacturing in Australia. This could involve manufacturing off-patent medicines with an emphasis on those medicines most used in Australia.

Not only would this create stable, high technology jobs in Australia, it would also contribute to our economy and make us less susceptible to future global drug supply problems.

Nial Wheate, Professor and Director Academic Excellence, Macquarie University and Shoohb Alassadi, Casual academic, pharmaceutical sciences, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Extreme heat is increasingly common in Australia and around the world and besides making us uncomfortable, it can harm our health. For example, exposure to extreme heat can exacerbate existing medical conditions, or cause problems such as heat stroke.

Due to a combination of physiology and behaviour, children are potentially more vulnerable to severe heat-related illness such as heat stroke or heat exhaustion.

But these are not the only heat-related health issues children might experience on a very hot day. In a new study, we looked at emergency department (ED) visits and unplanned hospital admissions among children in New South Wales on heatwave days.

We found a significant increase in children attending hospital compared to milder days – with a range of health issues.

Why are children more vulnerable in the heat?

Sweating is the main way we lose heat from our bodies and cool down.

Children have a greater skin surface area to body mass ratio, which can be an advantage for sweating – they can lose more heat through evaporation for a given body mass. But this also means children can lose fluids and electrolytes faster through sweating, theoretically making them more susceptible to dehydration.

Meanwhile, younger children, particularly babies, can’t sweat as much as older children and adults. This means they can’t cool down as effectively.

Children in general also tend to engage in more outdoor physical activity, which might see them more exposed to very hot temperatures.

Further, children may be less in-tune to the signals their body is giving them that they’re overheating, such as excessive sweating or red skin. So they might not stop and cool down when they need to. Young children especially may not recognise the early signs of heat stress or be able to express discomfort.

Our study

We wanted to examine children’s exposure to extreme heat stress and the associated risks to their health.

We measured extreme heat as “heatwave days”, at least two consecutive days with a daily maximum temperature above the 95th percentile for the relevant area on a universal thermal climate index. This ranged from 27°C to 45°C depending on the area.

We assessed health outcomes by looking at ED visits and unplanned hospital admissions among children aged 0–18 years from NSW between 2000 and 2020. This totalled around 8.2 million ED visits and 1.4 million hospital admissions.

We found hospital admissions for heat-related illness were 104% more likely on heatwave days compared to non-heatwave days, and ED visits were 78% more likely. Heat-related illness includes a spectrum of disorders from minor conditions such as dehydration to life-threatening conditions such as heat stroke.

But heat-related illness wasn’t the only condition that increased on heatwave days. There was also an increase in childhood infections, particularly infectious enteritis possibly related to food poisoning (up 6% for ED visits and 17% for hospital admissions), ear infections (up 30% for ED visits and 3% for hospital admissions), and skin and soft tissue infections (up 6% for ED visits and 4% for hospital admissions).

We know many infectious diseases are highly seasonal. Some, like the flu, peak in winter. But heat and humidity increase the risk of certain infections caused by bacterial, viral and fungal pathogens.

For example, warmer weather and higher humidity can increase the survival of bacteria, such as Salmonella, on foods, which increases the risk of food poisoning.

Hot weather can also increase the risk of ear infections. Children may be at greater risk during hot weather because they often swim or play at the beach or pool. Water can stay in the ear after swimming and a moist environment in the ear canal can cause growth of pathogens leading to ear infections.

Which children are most vulnerable?

During heatwaves, we found infants aged under one were at increased risk of ED visits and hospital admission for any reason compared to older children. This is not surprising, because babies can’t regulate their body temperature effectively and are reliant on their caregivers to keep them cool.

Our study also found children from the most disadvantaged areas were more vulnerable to heat-related illness on heatwave days. Although we don’t know exactly why, we hypothesised families from poorer areas might have limited access to air-conditioning and could be more likely to live in hotter neighbourhoods.

Keeping kids cool: tips for parents

The highest levels of heat exposure on hot days for young children is usually when they’re taken outside in prams and strollers. To protect their children from direct sunlight, parents often instinctively cover their stroller with a cloth such as a muslin.

However, a recent study from our group showed this actually increases temperatures inside a stroller to as much as 3–4˚C higher than outside.

But if the cloth is wet with water, and a small fan is used to circulate the air close to the child, stroller temperatures can be 4–5˚C lower than outside. Wetting the cloth every 15–20 minutes (for example, with a spray bottle) maintains the cooling effect.

When young children are not in a stroller, and for older children, there are a few things to consider to keep them cool and safe.

Remember temperatures reported on weather forecasts are measured in the shade, and temperatures in the sun can be up to 15˚C higher. So sticking to the shade as much as possible is important.

Exercise generates heat inside the body, so activities should be shortened, or rescheduled to cooler times of the day.

Sunscreen and hats are important when outdoors, but neither are especially effective for keeping cool. Spraying water on the child’s skin – not just the face but arms, legs and even the torso if possible – can help. Wetting their hats is another idea.

Proper hydration on hot days is also essential. Regular water breaks, including offering water before, during and after activity, is important. Offering foods with high water content such as watermelon and orange can help with hydration too.

Wen-Qiang He, Research Fellow in Biostatistics and Epidemiology, Faculty of Medicine and Health, University of Sydney; James Smallcombe, Post-doctoral Research Associate, Faculty of Medicine and Health, University of Sydney; Natasha Nassar, Professor of Paediatric and Perinatal Epidemiology and Chair in Translational Childhood Medicine, University of Sydney, and Ollie Jay, Professor of Heat & Health; Director of Heat & Health Research Incubator; Director of Thermal Ergonomics Laboratory, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.