The total circulating volume of a 1 year old is roughly the same as the amount of water you pour on your indoor pot plant. At about 80mls/kg it doesn’t take much loss before you have a significantly shocked baby on your hands. With circulatory function failing, oxygen and nutrients are not reaching the cells and cellular waste products are not being cleared.
Circulatory assessment is therefore a very important skill to develop in order to recognise the early signs of a shocked child.
Increased heart rate may indicate shock, or hypoxia. or fever, or anxiety.
Bradycardia is defined as a heart rate less than 60 or a rapidly falling heart rate with poor systemic perfusion. Bad, bad, bad.
Cardiac compressions will need to be commenced in infants with HR<60 and poor perfusion. You will probably be experiencing a holy crap moment at this time and be hesitant to begin CPR. If in doubt, just do it. *Unnecessary* chest compressions are almost never damaging.
pulse volume and blood pressure:
A good indicator of general perfusion can be made by palpating peripheral and central pulses. A poor central pulse with absent peripheral pulses is a sign of significant shock.
Remember: when fitting a blood pressure cuff to a childs arm it is vital to select the correct cuff size. The width of the cuff should cover no less than 80% the length of the upper arm.
The child’s blood pressure is a much less sensitive indicator, as it may remain *compensated* until circulatory collapse is imminent. You can estimate the expected systolic blood pressure with the following formula: BP= 80+(age in years * 2). A very low BP is a warning of imminent cardiac arrest, get busy!
A slow capillary refill time indicates poor skin perfusion. Press down firmly with your finger on the sternum for 5 seconds and release. ( alternatively you can use the nail bed or soles of the feet.) A normal capillary refill should occur within 2-3 seconds. Capillary refill time is not a useful indicator in the hypothermic patient.
Decreased perfusion will lead to an inability of the cells to *take out the trash*. The resulting metabolic acidosis will result in an increased respiratory rate and tidal volumes (without other signs of respiratory distress such as recession) as the lungs try and blow off carbonic acid.
The skin may appear mottled or marbled and cold to touch.
Decreased level of consciousness. Drowsiness and/or agitation may increase as cellular perfusion decreases. The most sensitive indicator of changes in mental state is of course the parents.
Decreased urine output due to decreased perfusion of the kidneys. Less than 2ml/kg/hour in infants and 1 ml/kg/hour in children is a red flag. Once again ask the parents for any history of decreased output.
As babies and infants develop significant circulatory compromise it is not exactly rocket science to pick that they are sick. As they begin to die they begin to look dead. But the sensitivity to pick up on early signs of shock is more of an art, and will make a big difference in outcome.
Here is a pretty good summation from the Emergency Medicine Journal for you to print out and leave in the toilet for reading. What… you don’t do your best study in the toilet?
This information is mostly gleaned from the excellent book Advanced Paediatric Life Support. The practical approach.