The purpose of this video is to provide general information and education about the care of
a critically ill child.
It is in no way a substitute for the independent decision making and judgment by a qualified
health care professional.
The information contained in this video should not be used to make a diagnosis or to overrule
the advice of a qualified healthcare provider, nor should it be used to provide advice for
emergency medical treatment.
Introduction to Burn Physiology by Dr. Robert Sheridan.
Please note that in this video, we will be following the guidelines used at Shiners Hospitals
for Children, Boston.
Some of this information may need to be modified based on the equipment, guidelines, and practices
in place in your institution.
Warning: some of the content of this video is extremely graphic, as it depicts the injuries
associated with severe burns.
Viewers unfamiliar with such injuries may find this material disturbing.
Hello my name is Rob Sheridan, and I work in the burn unit at the Shiners Hospital in
Boston.
What we're going to do is briefly talk about burn physiology.
We're first discuss the local response to a burn.
We'll talk briefly about the systemic response to a burn.
And then, briefly, the various important aspects of pediatric and geriatric physiology as it
relates to recovering from a burn.
Local Response.
I will talk briefly about the local response to burn injury.
What happens, you know, there's the thermal energy causes direct coagulaton of the tissue,
but then there's a peripheral area where there's damage that potentially is reversible.
A lot gets made of this zone of stasis and hyperemia where this potentially salvageable
areas of injured, but not necrotic skin.
And there may be something to this.
I think that where it comes into play most frequently is if there is a wound with some
peripheral areas that are not full thickness.
If the patient doesn't have a good quality fluid resuscitation, there may be some progression
of the wound in those areas that are threatened, but not necrotic.
So this is the local response to the burn.
A small burn, the response pretty much stays local.
And how do you manage the local response?
Well, you want to prevent hypoperfusion.
You want to do good resuscitation.
You want to prevent desiccation of the wound.
The purpose of the epithelium, in part, in large part, is to prevent desiccation of the
underlying dermis.
So you want to prevent that with your topical wound care plan.
And you want to prevent infection.
The epidermis also keeps the bacteria out, so you need to help the body along with that
issue.
So to manage the local injury, those are your goals: prevent hypoperfusion, desiccation,
and infection.
As the wounds get bigger, there becomes not just a local response, but a systemic response.
Exactly when this happens, and what burn size this happens, and what burn severity this
happens, is not entirely clear.
But it is quite common in burns under 15% or so the you see a relatively minimal systemic
response.
As the burns get bigger than that, the systemic response can become quite profound and quite
a problem.
And, again, there's a lots of ways to manage the goals of hypoperfusion prevention, desiccation
prevention, and infection.
There are a topical salves, topical ointments, topical liquids that can be put on.
There are membrane dressings, like illustrated here.
And we'll talk about these in more detail later.
But those are your goals as regards to local response.
Systemic Response.
So as the burns get bigger, the local response triggers a systemic response that can become
an increasing issue as the burns get larger.
This was initially well described by Cuthbertson, a Scott, a nutritionist.
And, he'd use the phrases as ebb and flow phases.
The ebb phase, referring kind of to the tide, being a period of hypoperfusion.
This is a period of hypotension related to hypovolemia, fluid gets lost through the wounds.
And we obscure this nowadays frequently with the fluid that we administer intravenously.
So the ebb phase is not quite as dramatic as it is in a setting in which a fluid resuscitations
are not done.
And, then he described the flow phase, which falls about 72 hours later in patients who
do survive the ebb phase.
And this is a period of increasing hyperdynamic circulation, increasing catabolic metabolism.
And this flow phase, or this hyperdynamic phase, will persist until well after wounds
are closed.
And in patients with very large injuries, it can persist a year or so after wound closure.
And this period is characterized by hyperdynamic circulation, protein catabolism, and glucose
intolerance.
How do you address the systemic response?
Well, the best way to do it is to remove the eschar as soon as it's obvious where it is
full thickness.
Close those wounds physiologically somehow.
And then support the hyperdynamic physiology as best you can.
There'll be increased needs for substrate.
There will be increased needs for volume.
So, to support those needs with nutritional support does help your patients survive that
phase of his care.
In patients in whom nutritional support is inadequate to this task, you really get into
a late systemic phase where there is a lot of catabolism.
And this really complicates their recovery.
It makes healing of their wounds and donor sites pretty much impossible.
It very much exaggerates the immune compromise that burn patients suffer.
And, so, very early, very aggressive attention to nutritional support of somebody with a
medium to large wound is really critical in avoiding this sort of late phase, catabolic
illness.
Pediatric Considerations.
Briefly, pediatric considerations are-- children are commonly burned.
The mechanisms are often a little bit different-- a lot more scalding, bathing, and cooking
accidents.
Airway is always an issue.
The pediatric airway, as you know, is much smaller than the adult airway.
As edema occurs in the head and neck, occlusion of the airway due to edema is much more rapid
than an adult with a full size trachea.
Children have higher energy needs per surface area unit.
They have a thinner skin.
They have exaggerated temperature loss.
All these things need really focused attention early on.
And from a practical perspective, they have smaller blood vessels.
Vascular access is more difficult and needs a little more attention to detail.
Having said that, there's no reason that children should have a higher mortality with the same
size injury as a young adult.
It's also very important to really keep in the forefront of your head that kids will
get cold easily, especially small children with thin skin, not a lot of insulation.
They're evaporating through their wounds.
They'll really get cold quickly.
You won't get cold.
They'll be cold.
This is particularly important in the operating room, because hypothermia will lead to coagulopathy.
And if you're doing an operation, it really demands an intact coagulation cascade to have
a successful outcome.
You really want to pay attention to this detail.
Constantly monitor the temperature of the child.
Injuries of abuse do occur in all age groups, probably more common in small children.
There are certain classic patterns and stories you want to be alert for.
This is one such, the flexor sparing across a popliteal fossa.
We'll talk a little bit more about this later.
But to have this in your mind as you go through the initial evaluation of patients is important.
And finally, kids grow.
And they outgrow their scars.
They outgrow their grafts.
And to keep them functioning normally requires periodic visits for reconstruction.
These operations are very straightforward in most cases.
They're very easy to do.
They're very well tolerated.
But they're best done as soon as they manifest rather than waiting.
Geriatric Considerations.
Geriatric considerations, again, the mechanisms tend to be a little different.
Sometimes, when very old patients are burned, it's part of their global deterioration in
their ability to interact with their environment.
They frequently have co-morbid issues.
They frequently have a reduced reserve.
There are sometimes advance directives or health care proxies that need to be brought
into the overall planning.
This ideally should be done extremely early so inappropriate things aren't done and inappropriate
paths not taken.
And, finally, they have very thin skin.
Like little children, they have an atrophic skin.
It doesn't heal well.
It doesn't tolerate donor site harvests very well.
And we'll talk later about some of the specific ways to address that operatively to get a
good outcome.
Finally, rehab can be more difficult for elderly patients.
They do best in their home environment.
Sometimes, that's very difficult, depending on the physical characteristics of the home
environment and who's living there and who can help.
And thinking about and planning a placement and the rehabilitative needs of elderly patients
is really important if you're going to give them a quality outcome.
Summary.
So, to summarize burn physiology, really there are local issues, there are systemic issues,
there are pediatric and geriatric unique aspects.
But really, it's all about the wound.
If you can address the wound efficiently, quickly, and with minimal morbidity related
to the operative event, you can really truncate the physiologic aberrations here very well.
And so if you can address the wound efficiently, everything else will get better.
That concludes our video on Introduction to Burn Physiology.
Please help us improve the content by providing us with some feedback.
What did or didn't you like about this video?
Was the content too simple, just right, or too difficult?
Was the length too short, just right, or too long?
Any additional comments?
You can either click the Start a New Discussion button and type in feedback or send us an
email at openpediatrics@c hildrens.harvard.edu.
Note, feedback is not required to complete this activity in the guided learning pathway.