Basic observations


Basic observations are an essential part of assessment and detection of clinically deteriorating patients. NHS England advocates the use of the National Early Warning Score 2 (NEWS2) for assessment of adult patients in acute and ambulance settings. This page will cover the techniques required to complete this assessment.

NEWS2 scoring table

The NEWS2 scoring table


Introduce yourself to the patient with your name and role, and confirm the patients name and date of birth. Explain that you are about to take some basic observations and obtain consent. Wash your hands.

If the patient is confused or unconscious, check their identity from their hospital wrist band.

Respiratory rate

Record the number of inspirations over a 30 second period. Multiple this by two to get the respiratory rate per minute.

A raised respiratory rate per minute (>20) or hyperventilation may be physiological, such as post-exercise or otherwise can be suggestive of hypoxaemia (low blood oxygen concentration), shock, metabolic acidosis, anxiety or stress.

A reduced respiratory rate per minute (<12), or hypoventilation can by caused by physical limitations such as chest trauma, obesity, obstructive sleep apnoea and neuromuscular disorders (such as myaesthenia gravis or Guillain Barré syndrome) or metabolic causes such as metabolic alkalosis, central nervous system depressants (alcohol and narcotics), brainstem stroke and severe hypothyroidism. Hyperoxia (over-oxygenation) in COPD will lead to a relative hypoventilation (see “hyperoxia in COPD” box in the next section).

Oxygen saturation

Attach a pulse oximeter to the patient’s index finger to record the patient’s blood oxygen saturation. This records the percentage of haemoglobin binding sites occupied by oxygen in the body. Normal oxygen saturation is 96% and above. Record whether or not the patient is receiving any oxygen and if so, then at what flow rate.

A low oxygen saturation (<96%) is almost always due to hypoxaemia (low blood oxygen concentration) as there is less oxygen available to bind to the haemoglobin. The most common cause of hypoxaemia is hypoxia (inadequate tissue oxygen) of the lung such as in COPD, asthma or pneumonia. Other causes include hypoventilation, high altitude, ventilation-perfusion mismatch (such as in pulmonary embolism [PE]) or left-to-right shunting of blood.

In patients with COPD, aim for a target of 88-92% as over-oxygenating these patients may lead to hypercapnia (high levels of blood carbon dioxide [CO2]).

A pulse oximeter measures the amount of red and infrared light waves absorbed by oxygenated haemoglobin in the blood. As a result, an accurate reading is dependent on good, peripheral vascular flow. If you are unable to get a reading with a finger pulse oximeter you may need to switch to an ear lobe pulse oximeter instead.

When recording a patient’s oxygen saturation, it is important to state how much oxygen the patient is receiving. In the UK, this is measured as “flow rate” and ranges from 1-15L per minute. A patient receiving no oxygen will be inhaling room air which is made up of 21% oxygen. A patient on oxygen will be inhaling both oxygen and room air, and so the fraction of oxygen inhaled will be dependent on the flow rate and the mode of delivery. For example:

Ventilation-perfusion (V/Q) mismatch is a situation in which well-ventilated areas of lung receive insufficient blood supply whilst poorly-ventilated areas receive good blood supply. The body tries to avoid VQ mismatches by hypoxic vasoconstriction, a mechanism in which lung hypoxia causes vasoconstriction of arterioles supplying blood to that area.

The respiratory drive that serves to influence the ventilatory muscles is partly determined by the central chemoreceptors in the medulla oblungata. Hypercapnia, hypoxaemia and a low pH will act to increase respiratory drive. Blood CO2 combines with water to form carbonic acid – thereby reducing blood pH and causes a respiratory acidosis. In patients with longstanding COPD there are certain changes to the body as follows:

With the above points in mind, if you increase the fraction of inhaled oxygen such that they entire lung is well oxygenated (or over-oxygenated in this case) the following problems develop:

As a result, the NEWS2 suggests maintaining blood oxygen saturation in patients with COPD and chronic hypercapnia between 88-92% in order to prevent hyperoxia and any subsequent worsening hypercapnia.

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Methaemoglobinaemia is a rare condition in which there is an excessive amount of methaemoglobin in the blood. Methaemoglobin is a form of haemoglobin where the iron has been converted from its ferrous (Fe2+) form to its ferric (Fe3+) form. This may be triggered by certain medications. Patients with a deficiency of methaemoglobin reduction enzyme (NADH-cytochrome b5 reductase) - such as those with a genetic deficiency or those under 6 months of age - are more susceptible to the condition.

It will present with a low blood oxygen saturations despite there being no evidence of hypoxaemia (i.e. there is a normal arterial oxygen level).

Systolic blood pressure

Record the patient’s blood pressure at rest. To do this, you will need:


Palpate for the brachial pulse, medial to the biceps brachii tendon. Line up the arrow marked on the cuff with the brachial artery and fasten the cuff around the patient’s arm.

Ensure that the valve is closed on the hand pump. Inflate the cuff whist palpating the radial pulse. At the point where you can no longer feel the pulse, read the meter; this is a rough estimate of the patient’s systolic blood pressure.

Deflate the cuff and close the valve again. Place the diaphragm of your stethoscope over the brachial pulse, just under the cuff.

Area of palpation and auscultation of the brachial artery.

Place the diaphragm just under the cuff.


Inflate the cuff to 20mmHg above your estimated systolic pressure. Next, by minimally opening the valve, slowly deflate at around 2-3mmHg/s, whilst watching the pressure dial.

Listen carefully for loud beating sounds called ‘Korotkoff sounds.’ When you first hear the sounds, read the meter; this will be the systolic pressure. You will continue to hear the sounds for a brief amount of time. Once the sounds have completely died away, read the meter again; this will be the diastolic pressure. Readings are usually taken to the nearest 2mmHg.

Record the systolic blood pressure.

For more on blood pressure measurement and interpretation, see the blood pressure measurement page.

Pulse rate

Palpate the radial pulse, just lateral to the tendon of the flexor carpi radialis. Record the number of beats over 15 seconds and multiple by 4 to give you the pulse rate (heart rate) per minute . If you are unable to palpate the radial pulse, then palpate the carotid pulse just anterior to the sternocleidomastoid muscle, underneath the angle of the jaw.

A raised pulse per minute (>100) or tachycardia may be physiological, such as post-exercise or otherwise may be secondary to fever, infection, arrythmia, shock, pulmonary hypertension (including PE), hyperthyroidism, fear/anxiety or stress.

A reduced pulse per minute (≤60), or bradycardia may also be physiological in fit patients who do a lot of aerobic exercise. Pathological causes include heart disease (such as ischaemia or heart block), hypothyroidism and certain medications such as beta-blockers.

A pulse oximeter will also measure the patient’s pulse rate per minute.

Note that the NEWS2 score scores tachycardia at >90 and bradycardia as ≤50 (pulse per minute).


Talk to the patient and assess their response via the ACVPU scale. If the patient is asleep, then you will need to wake them up:

A more detailed assessment of consciousness is the Glasgow Coma Scale which more accurately assesses the patient’s ocular, verbal and motor responses to interaction.


There are numerous methods of recording temperature:

A raised temperature (>38℃) or pyrexia may be caused by infection, inflammatory disease, cancers and drugs.

A reduced temperature (≤36℃) or hypothermia may be due to prolonged exposure to cold water or weather or caused by alcohol intoxication, certain medications and hypothyroidism.

Temperature may also be measured rectally, however this is only ever used in newborn babies, if at all, and should only be done by those who are trained to do so.


Ensure that your observations are recorded in the patient’s notes or observation chart. If you are using the NEWS2 system, use the scoring table to determine their NEWS2 score and take the following actions:

Interactive markscheme

When assessing each other, click on each list item as you go along. Doing so will turn the list item green. Make careful note of any steps missed at the end. We recommend completing any examination or procedure in under 10 minutes, but you can adjust the timer to suit your needs.

  1. Introduction: “Hello, I’m SimpleOSCE and I am a medical student. Today I’ve been asked to take some basic observations from you. Can I confirm your name and DOB? Thank you.”
  2. Obtain consent.
  3. Wash your hands.
  4. Record respiratory rate per minute over 30 seconds.
  5. Use a pulse oximeter to record blood oxygen saturation.
  6. Record the patient’s blood pressure.
  7. Record the pulse rate per minute over at least 15 seconds.
  8. Record consciousness via the ACVPU scale.
  9. Record the patient’s temperature by tympanic, oral or axillary means.
  10. Document your findings in the patients notes, using the NEWS2 score or otherwise.
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