How Do You Measure Oxygen (O₂) Saturation?

What is pulse rate?

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Pulse is the rhythmic expansion and contraction of the arteries as blood is pumped by the heart and which can be felt at certain locations of the body, most commonly the wrist (radial) and neck (carotid).

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Each pulsation represents a heartbeat, and the pulse rate is the number of heart beats per minute (bpm).

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Why measure pulse rate?

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A regular pulse indicates that your heart is effectively pumping blood throughout the body and our pulse rate can be reflective of our health in general such as physical fitness.

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In practice, it is most useful and the easiest to determine two features of the pulse:

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1. Pulse rate:

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At times, when the pulse is too high (tachycardia) or too low (bradycardia), it can be a sign of an underlying abnormality such as cardiovascular (heart) or thyroid problems.

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2. Pulse rhythm:

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Our heart (for the most part) should beat at a regular interval. When our heart beats irregularly this usually requires further investigation as it can be a sign of a rhythm abnormality of the heart.

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How do you measure pulse rate?

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To obtain an accurate pulse reading:

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1. Find a quiet and comfortable space:

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Choose a calm environment to minimize external influences on your pulse rate.

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2. Locate your pulse:

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Common pulse points include the wrist (radial artery) towards the thumb side (see below) and the neck (carotid artery).

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It is often easiest to use two to three fingertips (index, middle and fourth fingers) and applying light pressure at the site to feel the pulse.

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3. Count the beats:

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Using a timer or watch, count the number of beats you feel within a 60-second interval. Alternatively, count for 15 seconds and multiply by 4 to get your beats per minute.

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4. Ensure proper technique:

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Maintain a light touch when feeling for your pulse. Pressing too hard may obstruct blood flow, leading to inaccurate readings.

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5. Record your findings:

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Keep a log of your pulse rate, noting the time of day and any relevant activities or emotions. Regular monitoring helps identify patterns over time.

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What is a normal pulse rate?

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A normal resting pulse rate for adults typically falls between 60 and 100 bpm at rest. Athletes may have lower resting rates due to enhanced cardiovascular fitness.

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Remember, like blood pressure, pulse rate is dynamic and will go up and down depending on several factors including:

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• Age
• Body temperature
• Physical activity
• Pain
• Emotions and stress
• Medication
• Caffeine intake

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Understanding these factors can provide context to your pulse readings.

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Summary

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Monitoring your pulse can offer insights into cardiovascular fitness and help detect irregularities. If you notice persistent irregularities in your pulse rate consult a medical professional.

What is body temperature?

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Body temperature is one of the core 'observations' or 'vital signs' that reflects the balance between heat production and heat loss within the body. It is measured in degrees Celsius (°C) or Fahrenheit (°F).

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The average adult's normal body temperature hovers around 37 degrees Celsius (98.6 degrees Fahrenheit) but like blood pressure, individual variation exists with a range from 36.1°C (97°F) to 37.2°C (99°F).

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Temperature can also vary slightly depending on the time of day, activity level, and other factors. It is a useful marker to measure, especially when we are feeling unwell to confirm if there is fever. In some instances, our body temperature can drop too low and when extreme, this is called hypothermia.

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Why is it useful to measure body temperature?

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Measuring body temperature can help to:

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• ‍Detect an infection: When you have an infection, your body temperature will often rise. This is because your body is fighting off the infection and trying to raise the temperature of your body to make it more difficult for the bacteria or virus to grow.

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• ‍Identify other health problems: Sometimes, a high or low body temperature can be a sign of an underlying health problem, such as a thyroid disorder.

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How do you measure body temperature?

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There are several ways to measure your body temperature. The most common methods include:

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Oral thermometer:

This is one of the commonest types of thermometers. Place the thermometer under the tongue and with your mouth closed hold the thermometer in place until a reading is taken.

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Wait at least 15-30 minutes after eating or drinking hot/cold substances before taking an oral temperature.

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Rectal thermometer:

This is the most accurate type of thermometer, but it is not recommended for adults. Insert the probe gently into the rectum until the device beeps or the specified time elapses.

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Use a water-soluble lubricant (such as KY-Jelly).

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Axillary (armpit) thermometer:

‍This is a good option for children and babies. Place the thermometer under the armpit and hold the arm snugly against the body for the recommended time until the thermometer beeps.

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Keep the area as dry as possible when taking a measurement.

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Tympanic (ear) thermometer:

‍This is a quick and easy way to measure your temperature. Place the thermometer in the ear, click the button and hold it in place until it beeps.

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Pulling the ear gently can help straighten the ear canal and ensure a snug fit for an accurate reading.

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Infrared (forehead) thermometer:

This method is quick, non-invasive and suitable for children and adults. It is also useful when many measurements need to be taken quickly (e.g. in a screening setting). However, it may be less accurate than other forms of measurement. Point the thermometer at the forehead, click the button and wait until a reading is taken.
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Keep the forehead dry, free from sweat or hair for optimal results.

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Tips for accurate temperature readings

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1. Choose the right thermometer: different thermometers have specific uses, so choose the one most appropriate for the age group and situation.

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2. Follow manufacturer instructions: always adhere to the instructions provided with the thermometer as each device may have slightly different specifications.

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3. Rest before measurement: wait for at least 15 minutes after physical activity or consuming hot/cold substances before checking temperature.

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4. Consistent method: sticking to one method for consistency can help to monitor trends in body temperature over time.

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What is considered a fever?

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Fever: A body temperature of 38°C (100.4°F) or higher is indicative of a fever.

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Low-Grade Fever: some sources might use the term "low-grade fever" for temperatures slightly above the normal range but below 38°C (100.4°F).

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What is considered hypothermia?

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Hypothermia is when the body temperature drops dangerously low, to below 35°C (95°F).

Summary

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It is important to be aware that the method of measurement can affect the recorded temperature to a degree (not literally!). For example, oral, rectal, ear, and forehead temperature measurements may yield slightly different readings, however the cut-off ranges above for fever and hypothermia hold true.

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It can be helpful to be familiar with your own baseline temperature and recognize any significant deviations from your normal range.

What is evidence-based medicine?

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Evidence-based medicine (EBM) is as its name suggests - the application of medicine and healthcare based on the best available current evidence.

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Evidence-based medicine is specifically medicine that will adapt alongside new data and scientific discoveries. When clinical practice follows evidence-based medicine, it provides the best and most up-to-date care for patients. Thus, EBM is a fundamental cornerstone in the fast-paced world of healthcare.

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The journey of evidence-based medicine

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You may or may not be surprised to learn that medical treatments have not always followed evidence and indeed, this continues to be the case in many scenarios.

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From days of old, doctors have relied on their experience when treating patients and from days of even older, doctors have relied on hunches, medical traditions and even superstition. These approaches had their good and bad sides, but it could be inconsistent, based on guesswork and more often than not, fraught with subjectivity.

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As medicine and our understanding of health grew, the need for a more structured and evidence-driven approach became clear with evidence-based medicine beginning to take shape in the early 1990s. Instead of relying on tradition, feelings and conventional wisdom, doctors started using the best, most up-to-date scientific evidence to make decisions.

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Dr. David Sackett, a pioneer and arguably one of the 'fathers' of modern evidence-based medicine described it as:

"the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients."

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Since then, evidence-based medicine has vastly transformed the landscape of healthcare with a huge paradigm shift in what is accepted medical practice over time, particularly over the last century.

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The time before evidence-based medicine

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Just imagine a couple of scenarios if time-honoured traditions did not evolve with scientific advances in medicine:

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Bloodletting

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Bloodletting has a history spanning over 3,000 years and was popular throughout Europe in the Middle Ages and was for a long time accepted medical practice. Illness was thought related to bad 'humours' in the body, and bloodletting was one way of purging 'disease' from the body. You would be rightly concerned if you attended the doctors today with a skin rash and the solution was to drain some of your blood.

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We now know that in fact for the vast majority of people, blood loss results in illness. We know this because modern medicine has developed the ability to measure and quantify objective blood markers through laboratory testing in order to determine illness.

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Mental illness and Superstition

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In historical contexts, mental health was often intertwined with superstition, leading to the belief that mental illnesses were manifestations of supernatural forces. In many societies, individuals exhibiting unusual or erratic behaviour were perceived as being possessed by evil spirits or demons that required some sort of 'cleansing'. The prevailing lack of scientific understanding and medical knowledge contributed to the reliance on mystical explanations and therefore exorcism was considered a legitimate treatment for mental disorders at one point.

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It wasn't until the development of modern psychiatry and the understanding of psychological disorders being multi-factorial in origin and rooted in biology, neurochemistry and socio-environmental factors that such superstitious beliefs began to give way to evidence-based medical approaches in the treatment of mental health issues. This was also a key proponent in the gradual destigmatisation of societal attitudes towards mental health.

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Challenges

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One of the big challenges in the field of evidence-based medicine is the overwhelming amount of medical information available in a rapidly evolving landscape. Doctors need to sift through all of it to find the best evidence, reach consensus, continually refine guidelines and then translate this into clinical practice, all within the confines of finite resources. Best practice may not always be followed and overcoming these challenges will require ongoing training and support for healthcare providers.

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On top of that in today's world, there are genuine concerns surrounding the growing amount of quackery and misleading medical information out there. The widespread use of online platforms has made it easier for unverified and pseudo-scientific health advice to circulate, putting individuals at risk of falling victim to inaccurate or downright fraudulent practices. People may be bamboozled into promises of quick fixes or treatments that aren't proven to work, potentially suffering financial loss but moreover delaying proper treatment and putting their well-being at risk.

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The future of evidence-based medicine

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The future of evidence-based medicine holds exciting prospects as the convergence of technology (such as AI, genomics) and diverse data sets (for example electronic health records, wearable device information) fosters a more personalised and dynamic approach to healthcare.

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Collaborative efforts between clinicians, researchers, and technology experts are likely to accelerate the translation of research findings into more patient-centred healthcare, ultimately improving patient outcomes and driving the evolution of evidence-based medicine into a more dynamic and adaptive framework.

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Overall, think of evidence-based medicine as being your healthcare GPS. It makes sure doctors have a roadmap to follow, based on the best information out there. It keeps you safe, helps you get the most from your healthcare, and pushes medicine forward. As we keep embracing the power of EBM through global information exchange, healthcare will keep getting better to ensure that everyone receives optimal care.

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