RECOGNITION AND RESPONSE

Infants and children are naturally tachycardic because of their smaller stroke volumes.  This is a normal physiological response to ensure that they maintain an adequate cardiac output to meet the body’s needs.

Taking a pulse rate will enable you to determine if the patient is either bradycardic or tachycardic.  Bradycardia is a pre-terminal sign.  Extreme tachycardia with loss of variability is a highly reliable sign of severity.

Assessing a central pulse volume will give an indication of stroke volume.  A weak pulse is therefore a sign of reduced cardiac output. In circulatory failure (shock) the pulse can become ultimately impalpable. 

Blood Pressure:
It is very important to use right size cuff for measuring blood pressure in children. The correct size is the one with:

• Cuff width >80% of child’s upper arm length
• Cuff bladder >40% of the circumference of the arm

Video: Capillary refill time (CRT) - CRT is assessed by applying pressure for 5 seconds and then releasing. The CRT is the time (in seconds) for the skin colour to return to normal. Central CRT is best performed over the centre of the sternum. If the child is cold, because of ambient temperature, then the CRT will often be prolonged (i.e. >2 seconds), therefore this clinical sign needs to be used alongside other clinical signs.
This video is also avalable at: https://youtu.be/sYmSH6mYdzU

In a normal ambient temperature the skin of a healthy infant or child should be pink and warm to touch.

Skin colour and temperature can give a great deal of information. Hypoxia causes vasoconstriction and pallor. With deterioration the infant/child will become mottled and ultimately cyanosed. Cyanosis from circulatory failure (shock) is initially peripheral, whereas respiratory failure causes central cyanosis.

Effects on breathing

Circulatory failure (shock) will often cause a metabolic acidosis.  This metabolic acidosis will cause tachypnoea. 

Mental status

Circulatory failure can lead to agitation, drowsiness and ultimately loss of consciousness.  In young infants, such as the case above, the initial compromise may be difficult to detect except for subtle signs such as poor feeding or a child/infant who is not responding to usual cues.  The level of consciousness should be assessed using the AVPU system, as described in the Disability chapter.

Urine output

Normal urine output is:

Volumes less than this indicate inadequate renal perfusion from circulatory failure.  Trends in weight can be useful to assess water balance.

What is the aetiology?

Determining the underlying cause of circulatory failure is important to direct further management of the patient.

1. You have established the child has evidence of poor tissue perfusion and therefore shock.
2. Does the child have signs of hypovolaemia?
3. What is the cause of the hypovolaemia? (e.g. bleeding, inadequate fluid resuscitation, inappropriate diuretic use). A thorough review of the fluid balance charts, blood results and drug charts will be needed.
4. Is there evidence of sepsis? (e.g. pyrexia, source of infection, warm to touch)
5. Is there evidence of a cardiogenic cause? (e.g. h/o congenital heart diseases, cardiac surgeries)

Response

Immediate management of the shocked patient

1. Ensure airway patency
2. Give high flow oxygen via facemask with reservoir.
3. Ensure adequate breathing
4. Attach monitoring (oxygen saturations probe, ECG and BP)
5. Intravenous access (2 peripheral cannulae if possible).  Early Intraosseous needle if cannulation is not rapidly established. 
6. Give a fluid challenge and assess response (cautious if evidence of cardiogenic shock)
7. Treat the underlying cause
8. Re-assess

Figure: A Tibial Intraosseous needle (left – drill for insertion, right – manual needle). When using an Intraosseous needle the fluid should be administered with a 20ml syringe to avoid fluid entering the tissues

Video: Intraosseous (IO) insertion: note that in both videos the IO is aspirated to try and take a sample. As a mannequin is used no blood is aspirated in these examples. (This video is also available at: https://youtu.be/kac9P1nVzZg)

Fluid challenge:

Rapid fluid resuscitation is essential.

• Initially give 10mls/kg fluid bolus of a balanced crystalloid or 0.9% saline to all patients with shock (caution in cardiogenic shock or raised intracranial pressure)
• If shock persists a 2nd bolus can be given.

Patient response is then clinically re-assessed by monitoring their physiological variables, watching for a return to normal values (capillary refill, respiratory rate, BP, heart rate). In particular review the response of the heart rate to the boluses of fluid.

If the patient fails to respond or starts to develop any signs of pulmonary oedema, senior advice must be sought immediately.

Inform anaesthetist and consider inotropes if more than 40mls/kg needed.