Now there are a few very helpful external tools used for monitoring the oxygenation
of a patient.
One of the most popular and most frequently used is the pulse oximeter.
It can be a measurement tool that measures the oxygen saturation and trends in that oxygen
saturation.
The way that the pulse oximeter works is that it measures the percent of hemoglobin that
is fully saturated or bound with oxygen molecules.
It’s very important to remember that oxygen saturation does not equate to oxygen delivery
to the tissues and the pulse ox does not provide information about the effectiveness of ventilation
or the elimination of carbon dioxide.
An effective pulse oximeter needs pulsatile blood flow in order to determine oxygen saturation.
A pulse ox will display an inaccurate reading unless the pulse rate matches the ECG monitor.
And even then, we should be watching and monitoring other ways to determine the oxygenation and
gas exchange of the patient.
It’s important to reevaluate the patient if the pulse oximeter signals a decrease in
oxygen saturation, indicates a weak or absent signal, has an inaccurate pulse rate or doesn’t
detect a pulse at all.
Don't imagine that it's just a failure of the pulse ox, it actually could be a true
monitoring of a change in the condition of our patient.
Now it’s important that if we see that failing pulse oximeter that we re-evaluate the child
to determine if the patient is stable or if they need additional care.
If for some reason an infant probe is unavailable, we can use an adult probe around the hand
or the foot of an infant.
Capnography should be attached in order to monitor the concentration or partial pressure
of carbon dioxide in the expired air.
Normal expired air in a person who has proper circulation and respiration contains 35-40
mmHg of CO2 on the digital readout.
If CPR was being performed and a sudden sustained rise in CO2 to 35-40 mmHg occurs, this would
be an indication of a return of spontaneous circulation.
When CO2 is absent as measured with capnography, it means either the endotracheal tube is in
a wrong position or there is no circulation.
The goal with CPR is to see a reading of greater than 10 mmHg.
If the end tidal CO2 reading is less than 10 mmHg, CPR compression depth and rate should
be adjusted in order to improve circulation.
If a child is unable to maintain an effective airway, oxygenation or an adequate ventilation
on their own, intubation with an Endotracheal Tube should be considered.
It's vital that all ACLS and PALS providers know their limitations and their areas of
proficiency.
If a provider knows that they may be called upon to intubate a patient, they should be
sure to take advantage of any and all opportunities to improve their experience and skills in
order to proficiently be able to secure an advanced airway if the need arises.
In the case that an intubated patient begins to deteriorate, we should be ready to check
the following in order to rule out a treatable problem.
I'd ask questions like, "Is the tube displaced out of the trachea or has it gone into the
right or left main stem bronchus?"
"Has an obstruction developed caused by thick secretions, blood, a foreign body or pus?"
"Or is the tube being kinked?"
"Has the patient developed a simple or tension pneumothorax?"
Or, "has the equipment failed due to a disconnection in the O2 supply from the ventilation system,
a lean in the ventilator, a power supply failure or even a malfunction of the valves in the
bag or circuit?"
...can all cause cause this kind of failure.
So if there is a mechanical failure, we must remember to go back to the basics and even
begin to manually ventilate the patient with a bag valve mask if the patient is on a ventilator.
Watch for signs of correction which include good chest rise and fall with ventilations.
We should also be getting good lung sounds upon auscultation including listening over
the stomach in order to rule out an accidental esophageal intubation.
Check all your monitors including capnography, the ecg, pulse ox and the heart rate.
Be sure to suction the ET tube if an obstruction is suspected and if it's kinked due to the
patient being agitated or waking up, that's when we should consider sedatives and analgesics
with or without a neuromuscular blocker in order to reduce the agitation and control
ventilation and oxygenation.
It’s important to remember that if we cannot confirm proper tube placement in the airway,
direct visualization of the tube passing through the glottis is advised.
If the provider suspects that the cause of the deterioration is that the tube is misplaced
or not working correctly, removal of the original tube and ventilation with a bag mask device
may be the best route of treatment until a properly advanced airway solution can be completed.
Lastly, if the patient is complicating their oxygenation and ventilation due to agitation
after all other causes are ruled out, then the provider may consider medicinal treatments
in order to correct the problem.
If an analgesic is decided upon, one might consider fentanyl or morphine.
For sedation, one could consider lorazepam, or midazolam.
Lastly, Succinylcholine may be used if a neuromuscular blocking agent must be used.
If a paralytic agent is used, the provider must know that they can adequately oxygenate
and ventilate the patient with a basic airway management solution.