How to Measure and Record Vital Signs
Taking a set of vital signs will help you monitor the condition of your patient and identify if their condition is improving or deteriorating. First aiders and first responders may be trained to measure some, or all, of the five main vital signs. In this blog post we will look at how to measure and record vital signs in first aid.
The number of vital sign sets recorded will depend upon a number of factors:
- Time spent with the patient
- Seriousness of the patient condition (ie, how ‘sick’ they are)
- Any changes observed
It should be remembered that at all times when dealing with a patient you should explain what you want to do and obtain the patient’s consent before carrying out any vital sign measurements.
Vital sign #1 Pulse rate
Taking a patient’s pulse is an important part of your physical assessment and secondary survey.
Whist you can obtain this information electronically, you should always start by feeling the pulse yourself as this will give you more information.
What are you looking for when taking the pulse?
The obvious answer to this question is the number of beats per minute or pulse rate but in addition you should be feeling the pulse to see if it is regular or irregular. An irregular pulse can be an indication of Atrial Fibrillation (A-Fib).
If you discover an irregular pulse, this should prompt you to ask your patient if they have any heart conditions, or if they have ever been told they have Atrial Fibrillation or A-Fib. A-Fib may cause no symptoms at all but does significantly increase the risk of a stroke.
Another important piece of information to note when taking a patients pulse is the quality or strength of the pulse. You should note if the patients pulse is any of the following:
If the heart is pumping a large amount of blood with each heartbeat, the pulse will feel very strong. This strong pulse is called a “bounding” pulse
Weak or ‘thready‘
If the heart is pumping only a small amount of blood with each heartbeat, the pulse will be harder to detect. This type of pulse is called weak or thready. If the pulse is weak, you may have trouble feeling (palpating) the pulse at first.
What is the normal pulse rate?
A normal pulse in an adult is around 60 – 100 beats per minute (bpm).
Vital sign #2 Respiratory rate
Normal respiration is an automated process and does not require conscious effort. However, in the case of illness or trauma, a patient’s respiratory rate may become unusually fast or slow indicating the need for immediate medical attention.
The respiratory rate is simply the number of breaths an individual takes per minute.
Observe and count the rise and fall of the patients chest over a period of time. Count the number of breaths in 15 seconds and multiply by 4, 20 seconds and multiply by 3, 30 seconds and multiply by 2 or observe for a full minute.
Try to count the respiratory rate discreetly to gain a more accurate reading. Also be aware of patient dignity when counting the respiratory rate of a female patient. An ideal way to obtain the respiratory rate of a female is to do so whilst taking the patients pulse as this will prevent any awkwardness.
What are Normal Respiratory Rates?
Respiratory rates, like pulse rates, will vary with the patient’s age.
Adult: 12 – 20 breaths per minute
Child: 15 – 30 breaths per minute
Infant: 25 – 50 breaths per minute
Vital Sign #3 Oxygen Saturation (SpO2)
A pulse oximeter is a device intended for the non-invasive measurement of blood oxygen saturation (SpO2) and pulse rate.
Typically a pulse oximeter uses two LEDs (light-emitting diodes) generating red and infrared lights through a translucent part of the body. Bone, tissue, pigmentation, and venous vessels normally absorb a constant amount of light over time. Oxyhemoglobin and its deoxygenated form have significantly different absorption pattern.
The arteriolar bed normally pulsates and absorbs variable amounts of light during systole and diastole, as blood volume increases and decreases. The ratio of light absorbed at systole and diastole is translated into an oxygen saturation measurement.
The pulse oximeter should be placed on the patients finger. You should give the readings time to settle before taking note of the figures you are given. This can take anything from a few seconds to a minute or two depending upon a number of factors.
Normal oxygen saturation levels should be considered to be above 94% or 88% – 92% for a patient who has chronic lung disease.
Vital Sign #4 Blood Pressure (BP)
Every blood pressure reading consists of two numbers or levels. They are shown as one number on top of the other, for example 165/60. The first (or top) number is the systolic blood pressure. It is the highest level your blood pressure reaches when your heart contract.
The second (or bottom) number is the diastolic blood pressure. It is the lowest level your blood pressure reaches as your heart relaxes between beats.
How to record a manual blood pressure (BP)
To begin a manual blood pressure measurement, use a properly sized blood pressure cuff. Lightly press the stethoscope’s bell over the brachial artery just below the cuff’s edge.
Check for the patients pulse and inflate the cuff until the pulse stops. Add another 10-15 units on the pressure gauge. Checking the pulse during inflation prevents unnecessary discomfort caused by over-inflation of the cuff.
Listen with the stethoscope, slowly release the valve to maintain a slow deflation of the cuff and simultaneously observe the guage. When the pulse is heard in the stethoscope you have identified the patients systolic pressure.
Continue to deflate the cuff – when the pulse sound disappears you have identified the diastolic pressure.
Vital Sign #5 Temperature
A temperature reading is often taken from the ear canal. This is known as a typamic temperature reading as the thermoemeter uses the tymapanic membrane (ear drum) in order to record the body temperature. Both low and high body temperatures can be life-threatening.