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Hello Everybody!

Here is this week’s newsletter from Autonomic.


Things aren’t always what they seem.

Here are two examples of ‘maybe not’  in relation to diagnostic screening.

On first appearances it seems that there would be no doubts that most screening proposed would make a difference.

But when examined closely, these two studies did not support the medical diagnosis as they should have.

Aaron Carroll, The Incidental Economist, applies four questions when discussing a screening test.

They are

  1. Is the condition prevalent and severe enough to warrant screening? 
  2. Do we have a cost-effective means to screen the general population
  3. Does early diagnosis make a difference (that is, do we have treatments available that are more successful when patients are diagnosed earlier?) 
  4. Will an early diagnosis motivate people to use information gained from screening?

The BMJ reported upon the systematic review of studies that looked at the accuracy of tests used to identify pre-diabetes.

The study then reviewed the efficacy of the interventions used to to prevent diabetes.

In an astounding finding, it found the A1C marker that was being tested to identify pre-diabetes could not be relied upon.

Half of the people with an abnormal A1C didn’t have any glycemic abnormalities.

So there is no screening test for pre-diabetes that can be trusted. 

Carroll says

 That means that it’s both missing people who have prediabetes and putting people who         don’t into interventions they may not need.

 Since more intervention programs try and get people to adopt healthier lifestyles, there’s little harm in getting them to eat better and be more active. Some trials put people on metformin, though, and that does come with side effects. They all involve costs, too.

In a similar vein, JAMA has reported about an asthma study by Canadian researchers. 

They wanted to know whether a diagnosis of asthma could be ruled out after a period of time.

And whether asthma medications could be safely stopped.

This study reviewed 613 people that had been diagnosed with asthma over the previous five years.

(O)ver four visits they gave them a series of drug challenges and spirometry, a physical test of breathing capacity, to confirm or rule out the disorder. 

The researchers were able to rule out the diagnosis of asthma in 33% of the participants.

Some patients ( 2%) had been misdiagnosed and some (29.5%) had no clinical or laboratory evidence of asthma.

Needless to say the researchers concluded that patients with physician- diagnosed asthma who were not using daily asthma medications or had been weaned, should have their diagnosis reassessed.

To learn more about diabetes and asthma click here:


There are commonly prescribed and administered medications that require accurate weight measurement for safe prescribing.

Weight needs to be measured using equipment that is calibrated to maintain accuracy and precision.

Do you know where the scales are on the ward? And when they are calibrated?

Accurately weighing a patient is one of the admission assessment parameters that is consistently poorly measured.

One hospital has found that there was an eighteen per cent compliance in recording patient weight accurately

Blood pressure medication, sedation, chemotherapy and anti-thrombolytic medication all require accurate weight measurement for safe prescribing and administration.

In many clinical settings the incidence of poor compliance in obtaining and recording patient weight has led to unsafe care.

The importance of accurate weight measurement is especially relevant in intensive care units, care of bariatric patients; and patients with renal impairment.

When weight was recorded, nearly 25% of staff estimated the weight of patients. 

One practice that occurs is the visual estimation of the patient’s weight. 

But over 40% of patients needed an accurate weight to have had an informed clinical decision for treatment,

Now a barrier to an accurate weight may be the clinical status of the patient. They are just too unwell to be weighed.

But a more likely explanation is the lack of access to appropriate scales that accommodate the patient.

Also the scales may not be accurate.

Where this occurred, there was a large and unacceptable variance and inaccuracy in the estimation.

There was one study that tried averaging estimates of weight by different people.

It was thought that like the “wisdom of crowds” it would lead to a more accurate weight measure.

It was unreliable.

It is not only medication where an accurate weight is important, manual handling of patients and the number of staff and required equipment, radiation therapy doses also require accurate weight recordings for safe and effective patient care.

Evans sai

“Failure to obtain an accurate weight, and re‐assessment of weight, poses significant risks and should be seen as an unacceptable practice within the healthcare team.During any admission to hospital patients, and their families, should have full confidence the right dose of medication is prescribed and administered, or other interventions are undertaken to ensure optimal recovery. Recorded weight informs the planning of safe and quality care and minimises the risks to both the patient and the care providers.”

Accurate paediatric weight is important when prescribing medication but the same emphasis of accuracy in dosage is not that evident in adults.

Safe prescribing practice requires the prescriber to confirm the accuracy of the patient’s weight for weight-based dosages as well as recording the weight on the medication chart.

One study (Hilmer) identified significant medication safety concerns and a risk of adverse drug events in patients that took weight-based medication and who had not been accurately weighed.

An unknown weight of a patient also may have Occupational Health and Safety implications for nursing staff.

Equipment used may also have a weight limit, especially those used for manual handling of a patient.

Identifying where risk will occur to staff and patients can only occur with an accurate weight and the use of equipment that can handle the weight being moved.

Patients who are at risk of compromised skin integrity (either under or overweight) are also at risk of pressure ulcers.

A baseline weight at admission is the start of monitoring skin integrity along with the review of a patient’s nutritional status.

Accurate morning daily weights were essential in heart failure disease care management.

To obtain an accurate patient daily, weight, patients should be weighed every morning, after their first void and before they eat breakfast. 

To learn more about accurate weight:

Evans, Alison. “Positive patient outcomes in acute care: does obtaining and recording accurate weight make a difference?.” Australian Journal of Advanced Nursing, The 29.3 (2012): 62.

Hilmer, S. N., et al. “Failure to weigh patients in hospital: a medication safety risk.” Internal medicine journal 37.9 (2007): 647-650.


Normal isn’t always normal.

Taking vital signs on a patient is done many times as part of the rhythm of a nurse’s day.

It is a skill that is taught early on in a nurse’s education.

What if the temperature that is considered normal is not “normal”.

The body temperature of a healthy human being is considered normal at 98.6 degrees Fahrenheit (F) or 37 degrees Centigrade (C).

In the mid 1800’s, Carl Wunderlich, a medical director at Leipzig University hospital, conducted a study on the vital signs of over 25,000 patients.

The study found that the average temperature of a normal human being was 98.6 degrees Fahrenheit (F) or 37 degrees Centigrade (C).

The thermometer that was used was subsequently found to have been two degrees Centigrade higher than it should have been.

Freakonomics Radio has put together part of a podcast about this thermometer in the episode called “Bad Medicine, Part 1: The Story of 98.6.”

The thermometer that Wunderlich used was a non-registering thermometer, which meant that it had to be read in place.

It was awkward to use.

It only measured axillary temperatures.

A modern temperature study in 1992 reviewed the work of Carl Wunderlich. 

It was entitled A Critical Appraisal of 98.6°F, the Upper Limit of the Normal Body Temperature, and Other Legacies of Carl Reinhold August Wunderlich by Philip Mackowiak, Steven Wasserman and Myron Levine.

It found that that only eight per cent of the 148 people studied had a temperature of 98.6F.

So if 98.6 was normal, this meant that 92 per cent were abnormal.

The study found that the actual normal temperature was 98.2F or 36.8 C, with an upper limit of 37.7C or 99.9F.

So one person’s normal could be considered a fever in another with the the variations that occur from person to person.

Temperature varied for a number of study participants.

There is a 6AM trough for temperature and a peak between 4-6PM.

Women who are ovulating have elevated temperatures.

There was a tendency for higher temperatures to be recorded among black than among white subjects.

The study concluded 

Thirty-seven degrees centigrade (98.6°F) should be abandoned as a concept relevant to clinical thermometry; 37.2°C (98.9°F) in the early morning and 37.7°C (99.9°F) overall should be regarded as the upper limit of the normal oral temperature range in healthy adults aged 40 years or younger, and several of Wunderlich’s other cherished dictums should be revised.

An increase in temperature is not a reliable sign of disease or infection.

To learn more about “normal” temperature:

Thanks for supporting Autonomic.

See you next week.

Cheers from the Autonomic team