British Columbia Drug and Poison Information Centre (BC DPIC)

New guidelines from the health watchdog the National Institute for Health and Care Excellence (NICE) on the use of intravenous (IV) drips have prompted a flurry of headlines, with The Guardian reporting that, "Thousands of patients [are] dying from incorrect use of IV drips", and The Daily Telegraph claiming that, "Tens of thousands harmed in hospital by IV drip blunders".

Both newspapers present misleading figures that have been taken out of context. Their stats, which state that one in three patients die from too much fluid within days of surgery, are taken from the National Confidential Enquiry into Patient Outcome and Death (2011). The enquiry reported on a study of just 569 high-risk patients. Three of the patients were given too much fluid before their operation and one died.

Only approximately 10% of people having surgery are considered high risk. In fact, the NICE report says that less than 1% of all patients undergoing surgery die during the same hospital admission.

Still, the rates of non-fatal complications reported in the guidelines are disturbingly high and should be seen as a call to improve patient safety in this area.

 

What are intravenous (IV) drips used for?

Intravenous (IV) drips are used for a variety of reasons, including:

• giving daily fluid to people who cannot drink water, for example during surgery or because they are vomiting
• to replace lost fluid, such as from bleeding or severe diarrhoea
• to correct chemical or metabolic imbalance, such as having too much potassium inside the body
• to manage hydration if fluid is not being distributed around the body normally

The amount and composition of fluid given depends on a person's weight, physical condition, medical problems and medication.

 

What has prompted the warning?

The National Institute for Health and Care Excellence (NICE) has issued guidance on when and how IV fluids should be prescribed.

It states that there is evidence that as many as one in five patients on IV fluids and electrolytes (salts and minerals) suffer complications because of inappropriate use.

 

What are the risks of incorrect use?

If a patient receives too little fluid, it increases the risk of dehydration and in severe cases can lead to kidney failure.

The risks of receiving too much fluid often depend on individual circumstances, but they can include:

• excess fluid collecting inside the lungs, which can cause breathing difficulties and increased risk of pneumonia
• swelling of the ankles
• an imbalance of electrolytes in the blood, which can disrupt organs 
• heart failure in serious cases

There are different types and composition of fluids, which must be balanced to ensure electrolyte levels are correct and to keep the fluid circulating through the blood vessels.

 

What has NICE recommended?

NICE has provided comprehensive guidelines on prescribing IV fluids for medical professionals. Most of the recommendations are of a very technical nature and many are probably only of interest to health professionals. The recommendations can be read in full online.

They include increased education of health professionals on the principles of fluid management, regular checks of patients on fluids for possible "red flags" that indicate they are receiving too much or too little fluid, and that hospitals should identify an "IV fluids champion" to lead best practice for the management of IV fluids.

NICE is also working with the General Medical Council, the Medical Schools Council and the Centre for Pharmacy Postgraduate Education to develop an online learning tool for medical professionals.

The NICE guidance concludes by making a number of recommendations for further research into fluid management, such as:

• investigation into exactly how common complications of IV fluid therapy are
• identifying what the best type of fluid is for people who are in hypovolemic shock (where severe blood and fluid loss has occurred)
• identifying the most effective training methods for hospitals to use to improve care standards

Speaking at a press conference, one of the authors of the guidelines, Dr Mike Stroud, said: "It is astonishing really that doctors are not well educated in fluid therapy, but because it is not a speciality, it has fallen through the cracks.

"This new NICE guideline has training and education at its heart and will play a vital role in making sure that staff at all levels in the NHS deliver consistent, high-quality care for all patients."

 

Analysis by Bazian. Edited by NHS Choices.
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Links To The Headlines

Tens of thousands harmed in hospital by IV drip blunders. The Daily Telegraph, December 10 2013

One fifth of patients' drips 'are dangerous'. BBC News, December 10 2013

Nine in ten doctors are untrained in using a drip: Thousands of patients at risk because of lack of basic knowledge. Daily Mail, December 10 2013

'Staggering numbers' of patients at risk because medical staff aren't trained to use IV drips. The Independent, December 10 2013

Thousands of patients dying from incorrect use of IV drips, warns Nice. The Guardian, December 10 2013

"New test can give two years' warning of Alzheimer's," reports the Mail Online. The news comes from a small Canadian study that found that a specific change in brain activity seen on MRI testing, combined with certain memory difficulties, was 87.5% accurate at predicting the development of Alzheimer's disease.

The study looked at people with a condition known as mild cognitive impairment (MCI). MCI describes a range of symptoms that impact on cognition and memory, but not to such an extent that it seriously affects a person's day to day life. Some people with MCI will go on to develop Alzheimer's, although it is currently difficult to identify those who would benefit from treatment.

The researchers performed various cognitive tests and an MRI scan on 45 people with MCI and 20 healthy people. They followed both groups over two years and compared the results of the initial tests between those who developed dementia and those who did not.

They found that difficulties with memory retrieval of familiar information, coupled with thinning of the part of the brain associated with various emotional and thinking processes, could predict which people with MCI would go on to develop Alzheimer's disease.

This is not really a new test, as cognitive testing and MRI scans are already part of the diagnostic process for investigating the early signs of dementia.

The findings may help predict which people are at an increased risk of developing Alzheimer's disease, but the study size is too small for the results to change current medical practice. It is likely that these techniques will be used in larger populations to see if the results continue to be accurate.

 

Where did the story come from?

The study was carried out by researchers from the University of Montreal and was funded by the Canadian Institutes of Health Research (CIHR) and the Heart and Stroke Foundation of Canada.

It was published in the peer-reviewed Journal of Alzheimer's Disease.

The media reported the story fairly accurately, but were overly optimistic that the results of such a small trial could soon be used to predict the onset of Alzheimer's disease.

 

What kind of research was this?

This was a cohort study that followed a group of people with MCI and a group of healthy volunteers over a period of two years. MCI does not necessarily lead to dementia, and this study aimed to see if there were any factors that could predict which people with MCI would go on to develop the condition, in particular Alzheimer's disease.

Early diagnosis is important as the symptoms and signs of Alzheimer's disease may only become apparent many years after the condition has started. This could result in a lost opportunity to start drug treatment that could slow the progression of the condition. However, as this was a cohort study it can only show an association and cannot prove causality.

 

What did the research involve?

Researchers took a group of 45 people with MCI and a control group of 20 healthy elderly people recruited from the community with no symptoms of MCI. Both groups were followed up yearly for two years.

MCI was diagnosed in a memory disorders clinic through medical and neurological assessment, as well as cognitive testing. The condition was indicated by:

• cognitive memory complaint by the individual – the individual was aware they had memory problems
• reduced performance on clinical tests assessing memory, language or attention compared with that expected to be seen in line with age and education
• essentially normal ability to perform daily activities of living
• no dementia, as indicated by being above diagnostic thresholds on cognitive testing

People were excluded from the study if they had:

• alcohol dependence
• a general anaesthetic in the previous six months
• a history of a severe psychiatric disorder
• traumatic brain injury
• any other disease known to impair cognition

The study participants had further cognitive tests, including tests of word recall, working memory and planning abilities, as well as an MRI brain scan to look at:

• hippocampal volume (part of the brain involved with memory)
• cortical thickness (the outer layer of brain tissue)
• white matter hyperintensity volume (seen in ageing and some neurological conditions)

The researchers first compared the results between the two groups. They then compared the results of people with MCI who either did or did not develop dementia within the two years of the study. Lastly, they worked out which combination of results had the highest ability to predict which people would develop dementia.

 

What were the basic results?

Of the MCI group:

• 18 progressed to dementia – 15 with probable Alzheimer's disease and 3 with probable mixed dementia of Alzheimer's and vascular dementia
• 22 remained stable
• 5 were lost to follow-up

There were no differences between the control group and the MCI group in terms of age, gender or educational level.

As would be expected, at the beginning of the study the MCI group had significantly poorer memory than the controls for:

• immediate recall
• immediate recognition
• delayed free recall
• word pair learning

The MCI group also had significantly lower scores than the control group for working memory and planning abilities. There were no differences seen between the groups for task switching.

In terms of the MRI scan results, the average cortex thickness was significantly thinner in the group who developed dementia. It was also thinner in specific areas, such as the right anterior cingulate gyrus, a region of the brain thought to be associated with rational thought and decision making.

The researchers found that the combination of immediate recall and immediate recognition scores and the thickness of the cortex in the right anterior cingulate gyrus was the most accurate for predicting development of Alzheimer's, with an overall accuracy of 87.5%.

Specificity was 90.9% – that is, 90.9% of people who will not go on to develop Alzheimer's will not have the combination of recall and recognition problems or thinning of the right anterior cingulate gyrus.

Sensitivity was 83.3%, meaning that 83.3% of people who will go on to develop Alzheimer's will have this combination of test findings.

 

How did the researchers interpret the results?

The researchers concluded that their "findings suggest that detecting preclinical Alzheimer's disease is probably best accomplished by combining complementary information from targeted [brain] and cognitive classifiers, and highlight the importance of taking into account both structural and functional changes associated with the disease."

 

Conclusion

The researchers suggest that Alzheimer's disease can be predicted with an accuracy of 87.5% when thinning of the cortex in the right anterior cingulated gyrus is seen on MRI, alongside test results suggesting problems with recall and recognition.

This research does not indicate a new "test", as MRI and psychological testing are standard procedures when investigating the signs and symptoms of dementia. What is novel in this approach is looking at a specific combination of results as a potential way of predicting which people with MCI may develop Alzheimer's disease.

While this form of testing would be beneficial to accurately predict the onset of Alzheimer's disease, this was a small study that only followed people over the course of two years. Some forms of dementia can take years to develop. The results of the study would need to be replicated in a much bigger sample size before the technique could be used in clinical practice.

 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

New test can give two years warning of Alzheimers: Brain scan and memory exam has a 90 per cent accuracy rate. Mail Online, December 7 2013

Alzheimer's test can predict onset of the disease two years earlier than previously. Daily Mirror, December 7 2013

Links To Science

Peters F, Villeneuve S, Belleville S, et al. Predicting Progression to Dementia in Elderly Subjects with Mild Cognitive Impairment Using Both Cognitive and Neuroimaging Predictors. Journal of Alzheimer's Disease. Published online August 20 2013

“EU air quality rules are still too lax to protect us from pollution,” The Independent reports. It says that air quality regulations may not be sufficient to protect people from harmful sooty particles in traffic and factory fumes.

Pollutants are measured using a system known as particulate matter or PM, based on the size of the individual element; this is measured in micrometres. As a general rule, the lower the PM, the more dangerous the pollutant is, as very small particles are more likely to bypass the body’s defences and potentially cause lung and heart problems.

The research the newspaper reported on, which combined the results of 22 European studies in 367,251 people, found a 7% increase in mortality with each 5 micrograms per cubic metre increase in particulate matter with a diameter of 2.5 micrometres (PM2.5).

This was even after taking into account various socioeconomic, health and lifestyle factors. The increased risk was found even below the recommended European safety threshold currently set for PM2.5 concentration.

These findings are troubling as they suggest (though do not prove) that exposure to previously regarded ‘safe’ levels of air pollution may still be harmful.

Further analyses of the link with specific causes of death are planned, and these should help researchers to show whether the excess deaths are from causes that could biologically be linked with these pollutants.

 

Where did the story come from?

The study was carried out by researchers from Utrecht University in the Netherlands and various other European institutions and was funded by the European Community’s Seventh Framework Programme.

The study was published in the peer-reviewed medical journal The Lancet.

The UK media’s reporting of the study was accurate.

 

What kind of research was this?

The researchers say that various studies, particularly from the US, have shown that long term exposure to air pollution with a mass concentration of particulate matter (PM) smaller than 10 micrometres (PM10) or 2.5 micrometres (PM2.5) in diameter can have an influence on mortality.

However, few European studies are said to have investigated PM concentration effects on health and mortality, although some have shown associations between nitrogen dioxide (NO2) or nitrogen oxides (NOx) in the air and mortality.

The current research was part of the European Study of Cohorts for Air Pollution Effects (ESCAPE). This is an on-going project looking at the effects of air pollution on health.

The researchers combined standardised exposure assessments for PM, NO2 and NOx to health data from 22 ongoing European cohort studies to look at the association between exposure to these air pollutants and mortality. The current analysis specifically looked at death from any natural-cause. Future analyses will look at death from specific causes.

 

What did the research involve?

The research included 22 cohort studies from 13 countries across Europe and featured 367,251 participants.

The researchers measured the levels of certain air pollutants in the regions where the participants lived, and then identified which participants died over an average of about 14 years.

They then looked at whether those exposed to higher levels of different air pollutants were more likely to die during the study than those exposed to lower levels.

The participants included were selected from the general population. Some samples covered large areas of the respective country, including large cities and surrounding smaller rural communities. Recruitment to the studies was mainly during the 1990s, and the studies varied in the number and age of participants, and which other health and lifestyle factors were assessed.

The length of follow-up in the studies varied from six to 18 years (average 13.9 years). 

Participant deaths were identified through the countries’ death registers.

Deaths from natural-causes were identified on the basis of the underlying cause of death recorded on death certificates.

Causes of death not conceivably related to air pollution exposure (such as injury, accidents or suicide) were excluded.

The researchers estimated concentrations of air pollutants at the participants’ home addresses (at the start of the study) using a standard procedure. Air pollution was monitored between October 2008 and May 2011, and an average annual concentration of the pollutants PM10, PM2.5, NO2 and NOx was calculated.

As well as looking at pollutant concentrations, the researchers measured traffic intensity on the nearest road (vehicles per day), and total traffic load (intensity multiplied by length) on all major roads within a 100 metre buffer area. This was done as another way of estimating exposure to air pollution.

The researchers compared the risk of death over time between participants exposed to different levels of air pollutants. They took into account other factors that could affect risk of death (potential confounders). These were assessed based on questionnaires completed by participants at the start of the studies and included:

• year of enrolment into the study
• gender
• smoking status, smoking frequency and duration, and exposure to environmental tobacco smoke
• fruit and vegetable intake
• alcohol consumption
• body mass index (BMI)
• educational level, occupational class and employment status
• marital status
• socioeconomic status of the areas where the participants lived

 

What were the basic results?

During the study, 29,076 of the 367,251 participants died (8%). The average NO2 concentration ranged from 5.2 micrograms per cubic metre to 59.8 micrograms per cubic metre. The average PM2.5 concentration varied from 6.6 micrograms per cubic metre to 31.0 micrograms per cubic metre.

The pooled results of all cohorts revealed that each 5 microgram per cubic metre increase in PM2.5 concentration was associated with a 7% increase in mortality risk (hazard ratio [HR] 1.07, 95% confidence interval [CI] 1.02 to 1.13).

When looking at the association between mortality and different concentrations of PM2.5, there was a borderline significant increased risk of mortality when people were exposed to a concentration below the European annual mean limit of 25 micrograms per cubic metre (HR 1.06, 95% CI 1.00 to 1.12), and below 20 micrograms per cubic metre (HR 1.07, 95% CI 1.01 to 1.13).

At lower thresholds (15 or 10 micrograms per cubic metre) mortality was still raised, but this increase did not reach statistical significance.

There was no statistically significant association between mortality and increasing concentrations of NO2, NOx, PM10, traffic intensity on the nearest road or traffic intensity on major roads within 100 metres.

 

How did the researchers interpret the results?

The researchers conclude that “long-term exposure to fine particulate air pollution was associated with natural-cause mortality, even within concentration ranges well below the present European annual mean limit value”.

 

Conclusion

This is a valuable study combining the results of 22 European cohorts looking at the association between air pollutant concentration and overall mortality.

The analysis benefits from its large size, long duration of follow-up (average 13.9 years), ability to adjust for various potential confounders, and standardised measures of air pollution and mortality across studies.

The study found no association between mortality and average annual concentrations of PM10, NO2 and NOx or traffic intensity on nearest roads and major roads. However, they did find a 7% increase in mortality with each 5 micrograms per cubic metre increase in PM2.5 concentration. This link remained even after taking into account various socioeconomic, health and lifestyle factors. The findings are reported to be similar to those of a recent pooling of studies looking at the effect of PM2.5 on death from any cause.

Of particular note the researchers found significant associations with mortality at the European annual mean limit for PM2.5 of 25 micrograms per cubic metre. The World Health Organization’s air quality guideline suggests an annual mean limit for PM2.5 of 10 micrograms per cubic metre, and the authors suggest that their findings imply that moving towards this level could lead to health benefits.

The researchers note that when comparing the cohorts, they found that the variation in PM2.5 concentration was not solely related to traffic variables, but also seemed to vary according to population density, industrial sources, urban green space, and elevation above sea level.

Although measurement of air pollution was standardised, it is difficult to accurately measure how much pollution an individual is exposed to. The estimates in the current study were based only on the participants’ home addresses at the start of the study – these could change, and they could have different levels of exposure at work. More accurate measurements are likely to be difficult to obtain.

And despite adjustment for the measured confounders, it is still difficult to be certain that the PM2.5 concentration was itself the factor directly responsible for the increase in overall mortality risk.

However, the fact that this link was found consistently across different countries does seem to suggest it is a robust finding.

The findings suggest that even low air concentrations of fine particulate matter seem to be associated with mortality. This highlights the importance of continuing to work towards reducing levels of air pollution.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

EU air quality rules are still too lax to protect us from pollution, study finds. The Independent, December 9 2013

Even ‘safe’ levels of air pollution can harm your health. Daily Express, December 9 2013

Links To Science

Beelen R, Raaschou-Nielsen O, Stafoggia M, et al. Effects of long-term exposure to air pollution on natural-cause mortality: an analysis of 22 European cohorts within the multicentre ESCAPE project. The Lancet. Published online December 9 2013