Re: Question regarding fluid resuscitation

[Guest guest]

Gene,

I, as a practicing paramedic, did not get taught this; but I am glad you are

bringing it up. My question is in the situation of a trauma patient with severe

volume loss and only fluid on hand, will the increase in CPP by fluid

resuscitation be sufficient to perfuse the brain with the reduction in oxygen

carrying capacity as the circulating volume is diluted? It is possible to raise

pressure without increasing perfusion. Is there a happy medium, or should we

consider carrying other volume expanders?

Perhaps this would be an argument for the continued use of PASGs? Just a

thought.

Sent from my iPhone

McGee, EMT-P

> For the last few years, fluid resuscitation of trauma patients has been aimed

at maintaining a systolic BP of 80-90 mm Hg. The concept is that of " permissive

hypotension " based upon hydrostatic concerns about the effects of heightened

hydrostatic pressures in the fact of internal bleeding. It has been postulated

that increased hydrostatic pressures will dislodge clots that have been formed

as a natural response to injury, and that increased fluid volumes will dilute

clotting factors and lead to increased bleeding. These concepts are valid.

>

> However, I propose that this concept fails to take into consideration one

vital aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

>

> There are two components of blood pressure: the systolic and diastolic

readings. Systolic pressure represents hydrostatic pressure, and diastolic

pressure represents the degree of vasoconstriction. This is an

oversimplification, but it is

>

> basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg does

not insure adequate CPP.

>

> In order to figure CPP, one must first determine mean arterial pressure (MAP)

and estimate the intracranial pressure (ICP). Intracranial pressure cannot be

monitored in the field, but can be estimated based upon clinical observations.

>

> The formula for CPP is this: CPP = MAP - ICP.

>

> MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

>

> Normal patients without head injuries, at rest, have an ICP of from around 5

to 15 mm Hg. This can vary depending upon posture. For example, if a patient who

is supine suddenly stands up, his ICP will fall, and if he is dehydrated or

taking antihypertensives that antagonize alpha-1 vasoconstriction, he can become

dizzy or even faint. Conversely, when one coughs or sneezes, ICP spikes, but

only for a few seconds.

>

> With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

>

> Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg,

then MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In

fact, a CPP of 53 is close to the limit for survival.

>

> And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

>

> These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

>

> So my question is this: How many of you who are EMS educators use this in your

teaching? How many of you who are Paramedics have had this training and

understand these concepts?

>

> Are we doing enough to educate our medics to the basics of brain perfusion

with the current guidelines about fluid resuscitation?

>

> Gene Gandy, JD, LP, NREMTP

> PERCOMONLINE.COM

> Tucson, AZ

>

> .

>

>

[Guest guest]

Gene,

I, as a practicing paramedic, did not get taught this; but I am glad you are

bringing it up. My question is in the situation of a trauma patient with severe

volume loss and only fluid on hand, will the increase in CPP by fluid

resuscitation be sufficient to perfuse the brain with the reduction in oxygen

carrying capacity as the circulating volume is diluted? It is possible to raise

pressure without increasing perfusion. Is there a happy medium, or should we

consider carrying other volume expanders?

Perhaps this would be an argument for the continued use of PASGs? Just a

thought.

Sent from my iPhone

McGee, EMT-P

> For the last few years, fluid resuscitation of trauma patients has been aimed

at maintaining a systolic BP of 80-90 mm Hg. The concept is that of " permissive

hypotension " based upon hydrostatic concerns about the effects of heightened

hydrostatic pressures in the fact of internal bleeding. It has been postulated

that increased hydrostatic pressures will dislodge clots that have been formed

as a natural response to injury, and that increased fluid volumes will dilute

clotting factors and lead to increased bleeding. These concepts are valid.

>

> However, I propose that this concept fails to take into consideration one

vital aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

>

> There are two components of blood pressure: the systolic and diastolic

readings. Systolic pressure represents hydrostatic pressure, and diastolic

pressure represents the degree of vasoconstriction. This is an

oversimplification, but it is

>

> basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg does

not insure adequate CPP.

>

> In order to figure CPP, one must first determine mean arterial pressure (MAP)

and estimate the intracranial pressure (ICP). Intracranial pressure cannot be

monitored in the field, but can be estimated based upon clinical observations.

>

> The formula for CPP is this: CPP = MAP - ICP.

>

> MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

>

> Normal patients without head injuries, at rest, have an ICP of from around 5

to 15 mm Hg. This can vary depending upon posture. For example, if a patient who

is supine suddenly stands up, his ICP will fall, and if he is dehydrated or

taking antihypertensives that antagonize alpha-1 vasoconstriction, he can become

dizzy or even faint. Conversely, when one coughs or sneezes, ICP spikes, but

only for a few seconds.

>

> With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

>

> Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg,

then MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In

fact, a CPP of 53 is close to the limit for survival.

>

> And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

>

> These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

>

> So my question is this: How many of you who are EMS educators use this in your

teaching? How many of you who are Paramedics have had this training and

understand these concepts?

>

> Are we doing enough to educate our medics to the basics of brain perfusion

with the current guidelines about fluid resuscitation?

>

> Gene Gandy, JD, LP, NREMTP

> PERCOMONLINE.COM

> Tucson, AZ

>

> .

>

>

[Guest guest]

Gene. I have heard of this before, and did learn it many years ago, but I have

not seen it tough in a few years to be sure. In my paramedic class in the late

80's we did not even talk about it.

________________________________

To: texasems-l

Sent: Tue, June 28, 2011 4:54:58 AM

Subject: Question regarding fluid resuscitation

 

For the last few years, fluid resuscitation of trauma patients has been aimed at

maintaining a systolic BP of 80-90 mm Hg. The concept is that of " permissive

hypotension " based upon hydrostatic concerns about the effects of heightened

hydrostatic pressures in the fact of internal bleeding. It has been postulated

that increased hydrostatic pressures will dislodge clots that have been formed

as a natural response to injury, and that increased fluid volumes will dilute

clotting factors and lead to increased bleeding. These concepts are valid.

However, I propose that this concept fails to take into consideration one vital

aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

There are two components of blood pressure: the systolic and diastolic readings.

Systolic pressure represents hydrostatic pressure, and diastolic pressure

represents the degree of vasoconstriction. This is an oversimplification, but it

is

basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg does

not insure adequate CPP.

In order to figure CPP, one must first determine mean arterial pressure (MAP)

and estimate the intracranial pressure (ICP). Intracranial pressure cannot be

monitored in the field, but can be estimated based upon clinical observations.

The formula for CPP is this: CPP = MAP - ICP.

MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

Normal patients without head injuries, at rest, have an ICP of from around 5 to

15 mm Hg. This can vary depending upon posture. For example, if a patient who is

supine suddenly stands up, his ICP will fall, and if he is dehydrated or taking

antihypertensives that antagonize alpha-1 vasoconstriction, he can become dizzy

or even faint. Conversely, when one coughs or sneezes, ICP spikes, but only for

a few seconds.

With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg, then

MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In fact, a

CPP of 53 is close to the limit for survival.

And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

So my question is this: How many of you who are EMS educators use this in your

teaching? How many of you who are Paramedics have had this training and

understand these concepts?

Are we doing enough to educate our medics to the basics of brain perfusion with

the current guidelines about fluid resuscitation?

Gene Gandy, JD, LP, NREMTP

PERCOMONLINE.COM

Tucson, AZ

..

[Guest guest]

Gene. I have heard of this before, and did learn it many years ago, but I have

not seen it tough in a few years to be sure. In my paramedic class in the late

80's we did not even talk about it.

________________________________

To: texasems-l

Sent: Tue, June 28, 2011 4:54:58 AM

Subject: Question regarding fluid resuscitation

 

For the last few years, fluid resuscitation of trauma patients has been aimed at

maintaining a systolic BP of 80-90 mm Hg. The concept is that of " permissive

hypotension " based upon hydrostatic concerns about the effects of heightened

hydrostatic pressures in the fact of internal bleeding. It has been postulated

that increased hydrostatic pressures will dislodge clots that have been formed

as a natural response to injury, and that increased fluid volumes will dilute

clotting factors and lead to increased bleeding. These concepts are valid.

However, I propose that this concept fails to take into consideration one vital

aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

There are two components of blood pressure: the systolic and diastolic readings.

Systolic pressure represents hydrostatic pressure, and diastolic pressure

represents the degree of vasoconstriction. This is an oversimplification, but it

is

basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg does

not insure adequate CPP.

In order to figure CPP, one must first determine mean arterial pressure (MAP)

and estimate the intracranial pressure (ICP). Intracranial pressure cannot be

monitored in the field, but can be estimated based upon clinical observations.

The formula for CPP is this: CPP = MAP - ICP.

MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

Normal patients without head injuries, at rest, have an ICP of from around 5 to

15 mm Hg. This can vary depending upon posture. For example, if a patient who is

supine suddenly stands up, his ICP will fall, and if he is dehydrated or taking

antihypertensives that antagonize alpha-1 vasoconstriction, he can become dizzy

or even faint. Conversely, when one coughs or sneezes, ICP spikes, but only for

a few seconds.

With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg, then

MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In fact, a

CPP of 53 is close to the limit for survival.

And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

So my question is this: How many of you who are EMS educators use this in your

teaching? How many of you who are Paramedics have had this training and

understand these concepts?

Are we doing enough to educate our medics to the basics of brain perfusion with

the current guidelines about fluid resuscitation?

Gene Gandy, JD, LP, NREMTP

PERCOMONLINE.COM

Tucson, AZ

..

[Guest guest]

,

There comes a point at which a patient needs blood. Period. I don't know how

low hematocrit can go and still be adequate to perfuse the brain. Anybody care

to comment on that? Of course, there are vasopressors, but my motto is don't

give a vasopressor to an empty tank.

Gene

Re: Question regarding fluid resuscitation

Gene,

I, as a practicing paramedic, did not get taught this; but I am glad you are

bringing it up. My question is in the situation of a trauma patient with severe

volume loss and only fluid on hand, will the increase in CPP by fluid

resuscitation be sufficient to perfuse the brain with the reduction in oxygen

carrying capacity as the circulating volume is diluted? It is possible to raise

pressure without increasing perfusion. Is there a happy medium, or should we

consider carrying other volume expanders?

Perhaps this would be an argument for the continued use of PASGs? Just a

thought.

Sent from my iPhone

McGee, EMT-P

> For the last few years, fluid resuscitation of trauma patients has been aimed

at maintaining a systolic BP of 80-90 mm Hg. The concept is that of " permissive

hypotension " based upon hydrostatic concerns about the effects of heightened

hydrostatic pressures in the fact of internal bleeding. It has been postulated

that increased hydrostatic pressures will dislodge clots that have been formed

as a natural response to injury, and that increased fluid volumes will dilute

clotting factors and lead to increased bleeding. These concepts are valid.

>

> However, I propose that this concept fails to take into consideration one

vital aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

>

> There are two components of blood pressure: the systolic and diastolic

readings. Systolic pressure represents hydrostatic pressure, and diastolic

pressure represents the degree of vasoconstriction. This is an

oversimplification, but it is

>

> basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg does

not insure adequate CPP.

>

> In order to figure CPP, one must first determine mean arterial pressure (MAP)

and estimate the intracranial pressure (ICP). Intracranial pressure cannot be

monitored in the field, but can be estimated based upon clinical observations.

>

> The formula for CPP is this: CPP = MAP - ICP.

>

> MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

>

> Normal patients without head injuries, at rest, have an ICP of from around 5

to 15 mm Hg. This can vary depending upon posture. For example, if a patient who

is supine suddenly stands up, his ICP will fall, and if he is dehydrated or

taking antihypertensives that antagonize alpha-1 vasoconstriction, he can become

dizzy or even faint. Conversely, when one coughs or sneezes, ICP spikes, but

only for a few seconds.

>

> With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

>

> Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg,

then MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In

fact, a CPP of 53 is close to the limit for survival.

>

> And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

>

> These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

>

> So my question is this: How many of you who are EMS educators use this in your

teaching? How many of you who are Paramedics have had this training and

understand these concepts?

>

> Are we doing enough to educate our medics to the basics of brain perfusion

with the current guidelines about fluid resuscitation?

>

> Gene Gandy, JD, LP, NREMTP

> PERCOMONLINE.COM

> Tucson, AZ

>

> .

>

>

[Guest guest]

Gene,

While that is not in the text I/we use for our medic courses (which is Brady)

......which tells us that it's not in the NSC.....it has been taught in ITLS now

for some time and for that reason is taught in our medic classes. As you point

out, the theory explains the reason for targeting a somewhat higher systolic in

a hypotensive patient with a CHI, which is also part of our protocols. I suppose

this is becoming more common to EMS protocols hopefully everywhere (?). And I

would presume this is also taught in PHTLS (?). A good question to ask sir.

Don,

Tyler

________________________________

From: Wegandy wegandy@... >

To: texasems-l

Sent: Tue, June 28, 2011 4:54:58 AM

Subject: Question regarding fluid resuscitation

For the last few years, fluid resuscitation of trauma patients has been aimed at

maintaining a systolic BP of 80-90 mm Hg. The concept is that of " permissive

hypotension " based upon hydrostatic concerns about the effects of heightened

hydrostatic pressures in the fact of internal bleeding. It has been postulated

that increased hydrostatic pressures will dislodge clots that have been formed

as a natural response to injury, and that increased fluid volumes will dilute

clotting factors and lead to increased bleeding. These concepts are valid.

However, I propose that this concept fails to take into consideration one vital

aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

There are two components of blood pressure: the systolic and diastolic readings.

Systolic pressure represents hydrostatic pressure, and diastolic pressure

represents the degree of vasoconstriction. This is an oversimplification, but it

is

basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg does

not insure adequate CPP.

In order to figure CPP, one must first determine mean arterial pressure (MAP)

and estimate the intracranial pressure (ICP). Intracranial pressure cannot be

monitored in the field, but can be estimated based upon clinical observations.

The formula for CPP is this: CPP = MAP - ICP.

MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

Normal patients without head injuries, at rest, have an ICP of from around 5 to

15 mm Hg. This can vary depending upon posture. For example, if a patient who is

supine suddenly stands up, his ICP will fall, and if he is dehydrated or taking

antihypertensives that antagonize alpha-1 vasoconstriction, he can become dizzy

or even faint. Conversely, when one coughs or sneezes, ICP spikes, but only for

a few seconds.

With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg, then

MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In fact, a

CPP of 53 is close to the limit for survival.

And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

So my question is this: How many of you who are EMS educators use this in your

teaching? How many of you who are Paramedics have had this training and

understand these concepts?

Are we doing enough to educate our medics to the basics of brain perfusion with

the current guidelines about fluid resuscitation?

Gene Gandy, JD, LP, NREMTP

PERCOMONLINE.COM

Tucson, AZ

..

[Guest guest]

Toni,

It pretty much boils down to what I wrote below. Not a whole lot to add.

Gene

Question regarding fluid resuscitation

For the last few years, fluid resuscitation of trauma patients has been aimed at

maintaining a systolic BP of 80-90 mm Hg. The concept is that of " permissive

hypotension " based upon hydrostatic concerns about the effects of heightened

hydrostatic pressures in the fact of internal bleeding. It has been postulated

that increased hydrostatic pressures will dislodge clots that have been formed

as a natural response to injury, and that increased fluid volumes will dilute

clotting factors and lead to increased bleeding. These concepts are valid.

However, I propose that this concept fails to take into consideration one vital

aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

There are two components of blood pressure: the systolic and diastolic readings.

Systolic pressure represents hydrostatic pressure, and diastolic pressure

represents the degree of vasoconstriction. This is an oversimplification, but it

is

basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg does

not insure adequate CPP.

In order to figure CPP, one must first determine mean arterial pressure (MAP)

and estimate the intracranial pressure (ICP). Intracranial pressure cannot be

monitored in the field, but can be estimated based upon clinical observations.

The formula for CPP is this: CPP = MAP - ICP.

MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

Normal patients without head injuries, at rest, have an ICP of from around 5 to

15 mm Hg. This can vary depending upon posture. For example, if a patient who is

supine suddenly stands up, his ICP will fall, and if he is dehydrated or taking

antihypertensives that antagonize alpha-1 vasoconstriction, he can become dizzy

or even faint. Conversely, when one coughs or sneezes, ICP spikes, but only for

a few seconds.

With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg, then

MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In fact, a

CPP of 53 is close to the limit for survival.

And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

So my question is this: How many of you who are EMS educators use this in your

teaching? How many of you who are Paramedics have had this training and

understand these concepts?

Are we doing enough to educate our medics to the basics of brain perfusion with

the current guidelines about fluid resuscitation?

Gene Gandy, JD, LP, NREMTP

PERCOMONLINE.COM

Tucson, AZ

..

[Guest guest]

The latest paramedic textbook series, Professional Paramedic, by Beebe and

Myers, Delmar (full disclosure: I contributed to the writing of parts of the

series) covers this nicely in the section on head trauma.

Gene

Question regarding fluid resuscitation

For the last few years, fluid resuscitation of trauma patients has been aimed at

maintaining a systolic BP of 80-90 mm Hg. The concept is that of " permissive

hypotension " based upon hydrostatic concerns about the effects of heightened

hydrostatic pressures in the fact of internal bleeding. It has been postulated

that increased hydrostatic pressures will dislodge clots that have been formed

as a natural response to injury, and that increased fluid volumes will dilute

clotting factors and lead to increased bleeding. These concepts are valid.

However, I propose that this concept fails to take into consideration one vital

aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

There are two components of blood pressure: the systolic and diastolic readings.

Systolic pressure represents hydrostatic pressure, and diastolic pressure

represents the degree of vasoconstriction. This is an oversimplification, but it

is

basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg does

not insure adequate CPP.

In order to figure CPP, one must first determine mean arterial pressure (MAP)

and estimate the intracranial pressure (ICP). Intracranial pressure cannot be

monitored in the field, but can be estimated based upon clinical observations.

The formula for CPP is this: CPP = MAP - ICP.

MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

Normal patients without head injuries, at rest, have an ICP of from around 5 to

15 mm Hg. This can vary depending upon posture. For example, if a patient who is

supine suddenly stands up, his ICP will fall, and if he is dehydrated or taking

antihypertensives that antagonize alpha-1 vasoconstriction, he can become dizzy

or even faint. Conversely, when one coughs or sneezes, ICP spikes, but only for

a few seconds.

With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg, then

MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In fact, a

CPP of 53 is close to the limit for survival.

And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

So my question is this: How many of you who are EMS educators use this in your

teaching? How many of you who are Paramedics have had this training and

understand these concepts?

Are we doing enough to educate our medics to the basics of brain perfusion with

the current guidelines about fluid resuscitation?

Gene Gandy, JD, LP, NREMTP

PERCOMONLINE.COM

Tucson, AZ

..

[Guest guest]

Gene,

I was not taught in Paramedic school but that was a little bit ago. I was

taught the concept in CCEMT-P, TCCC and PHTLS/ITLS.

You can put all the NON-oxygen carrying volume you want but there comes a point

that you have a lot of fluid and only one little cell trying to oxygenate the

body and brain. I am also with you on vasopressors, they have there place but

not when it comes to an empty tank.

There is at least one study out there saying low hematocrit through hemodilution

increases ICP and causes a worsened neurological outcome.

So you can give your patient fluids to help meet your CCP and MAP levels and

help decrease the ICP. However, Because you've had a loss of volume through a

bleed somewhere, you give the fluids which causes hemodilution which causes low

hematocrit which causes increased ICP so you are potentially causing the very

thing which you are trying to avoid or help treat in the first place. The

answer? Blood and/or blood products. You can do many things to help with the

increased ICP issues: good oxygenation to assist your lone cell trying to

oxygenate, raise the head of the bed slightly which can sometimes decrease the

ICP, hypothermia is sometimes helpful, watch your glucose levels, mannitol,

steroids (although research is showing that steroids should not be used in

TBI),blood and/or blood products, AND adequate sedation and pain treatment.

I've looked to see if there was an article or study on the internet saying at

what hematocrit level does oxygenation cease and can't find one. I found

research saying in general hematocrit levels <23% increase mortality but still

nothing specific to at what point does oxygenation cease.

Now that I have put in my two cents worth I'll go back to my bat cave....

>

> > For the last few years, fluid resuscitation of trauma patients has been

aimed at maintaining a systolic BP of 80-90 mm Hg. The concept is that of

" permissive hypotension " based upon hydrostatic concerns about the effects of

heightened hydrostatic pressures in the fact of internal bleeding. It has been

postulated that increased hydrostatic pressures will dislodge clots that have

been formed as a natural response to injury, and that increased fluid volumes

will dilute clotting factors and lead to increased bleeding. These concepts are

valid.

> >

> > However, I propose that this concept fails to take into consideration one

vital aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

> >

> > There are two components of blood pressure: the systolic and diastolic

readings. Systolic pressure represents hydrostatic pressure, and diastolic

pressure represents the degree of vasoconstriction. This is an

oversimplification, but it is

> >

> > basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg

does not insure adequate CPP.

> >

> > In order to figure CPP, one must first determine mean arterial pressure

(MAP) and estimate the intracranial pressure (ICP). Intracranial pressure cannot

be monitored in the field, but can be estimated based upon clinical

observations.

> >

> > The formula for CPP is this: CPP = MAP - ICP.

> >

> > MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

> >

> > Normal patients without head injuries, at rest, have an ICP of from around 5

to 15 mm Hg. This can vary depending upon posture. For example, if a patient who

is supine suddenly stands up, his ICP will fall, and if he is dehydrated or

taking antihypertensives that antagonize alpha-1 vasoconstriction, he can become

dizzy or even faint. Conversely, when one coughs or sneezes, ICP spikes, but

only for a few seconds.

> >

> > With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

> >

> > Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg,

then MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In

fact, a CPP of 53 is close to the limit for survival.

> >

> > And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

> >

> > These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

> >

> > So my question is this: How many of you who are EMS educators use this in

your teaching? How many of you who are Paramedics have had this training and

understand these concepts?

> >

> > Are we doing enough to educate our medics to the basics of brain perfusion

with the current guidelines about fluid resuscitation?

> >

> > Gene Gandy, JD, LP, NREMTP

> > PERCOMONLINE.COM

> > Tucson, AZ

> >

> > .

> >

> >

[Guest guest]

Good information, .

GG

Re: Question regarding fluid resuscitation

Gene,

I was not taught in Paramedic school but that was a little bit ago. I was taught

the concept in CCEMT-P, TCCC and PHTLS/ITLS.

You can put all the NON-oxygen carrying volume you want but there comes a point

that you have a lot of fluid and only one little cell trying to oxygenate the

body and brain. I am also with you on vasopressors, they have there place but

not when it comes to an empty tank.

There is at least one study out there saying low hematocrit through hemodilution

increases ICP and causes a worsened neurological outcome.

So you can give your patient fluids to help meet your CCP and MAP levels and

help decrease the ICP. However, Because you've had a loss of volume through a

bleed somewhere, you give the fluids which causes hemodilution which causes low

hematocrit which causes increased ICP so you are potentially causing the very

thing which you are trying to avoid or help treat in the first place. The

answer? Blood and/or blood products. You can do many things to help with the

increased ICP issues: good oxygenation to assist your lone cell trying to

oxygenate, raise the head of the bed slightly which can sometimes decrease the

ICP, hypothermia is sometimes helpful, watch your glucose levels, mannitol,

steroids (although research is showing that steroids should not be used in

TBI),blood and/or blood products, AND adequate sedation and pain treatment.

I've looked to see if there was an article or study on the internet saying at

what hematocrit level does oxygenation cease and can't find one. I found

research saying in general hematocrit levels <23% increase mortality but still

nothing specific to at what point does oxygenation cease.

Now that I have put in my two cents worth I'll go back to my bat cave....

>

> > For the last few years, fluid resuscitation of trauma patients has been

aimed at maintaining a systolic BP of 80-90 mm Hg. The concept is that of

" permissive hypotension " based upon hydrostatic concerns about the effects of

heightened hydrostatic pressures in the fact of internal bleeding. It has been

postulated that increased hydrostatic pressures will dislodge clots that have

been formed as a natural response to injury, and that increased fluid volumes

will dilute clotting factors and lead to increased bleeding. These concepts are

valid.

> >

> > However, I propose that this concept fails to take into consideration one

vital aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

> >

> > There are two components of blood pressure: the systolic and diastolic

readings. Systolic pressure represents hydrostatic pressure, and diastolic

pressure represents the degree of vasoconstriction. This is an

oversimplification, but it is

> >

> > basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg

does not insure adequate CPP.

> >

> > In order to figure CPP, one must first determine mean arterial pressure

(MAP) and estimate the intracranial pressure (ICP). Intracranial pressure cannot

be monitored in the field, but can be estimated based upon clinical

observations.

> >

> > The formula for CPP is this: CPP = MAP - ICP.

> >

> > MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

> >

> > Normal patients without head injuries, at rest, have an ICP of from around 5

to 15 mm Hg. This can vary depending upon posture. For example, if a patient who

is supine suddenly stands up, his ICP will fall, and if he is dehydrated or

taking antihypertensives that antagonize alpha-1 vasoconstriction, he can become

dizzy or even faint. Conversely, when one coughs or sneezes, ICP spikes, but

only for a few seconds.

> >

> > With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

> >

> > Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg,

then MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In

fact, a CPP of 53 is close to the limit for survival.

> >

> > And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

> >

> > These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

> >

> > So my question is this: How many of you who are EMS educators use this in

your teaching? How many of you who are Paramedics have had this training and

understand these concepts?

> >

> > Are we doing enough to educate our medics to the basics of brain perfusion

with the current guidelines about fluid resuscitation?

> >

> > Gene Gandy, JD, LP, NREMTP

> > PERCOMONLINE.COM

> > Tucson, AZ

> >

> > .

> >

> >

[Guest guest]

from a field perspective, giving fluids to temporarily maintain B/P and CPP

is just that....a temporary effort.

from a clinical perspective, I've seen many folks 'walking, talking and

potty trained' with H/H of 5g/15%- they do tend to decompensate rapidly when

stressed. I think that the still ambulatory patient with the lowest reading

was around 3.9/11%....

any time there is leaking from the vascular system, fluid replacement is

only the first step. The critical step is fixing the leak- In trauma, this is

generally with transfusion followed by surgery (or surgery followed by

transfusion, depending on the situation). For other conditions, other fixes

may apply....for example, relieving a chronic bladder neck obstruction with a

Foley catheter may result in a profound diuresis- possibly over 3

liters/hour- appropriate fluid replacement (baseline plus 3/4ths of the hourly

output x 24 hours, then baseline plus 1/2 hourly output for 24 hours, etc) and

tincture of time will fix this problem.

ck

In a message dated 06/30/11 01:04:45 Central Daylight Time,

txladymedic@... writes:

I've looked to see if there was an article or study on the internet saying

at what hematocrit level does oxygenation cease and can't find one. I

found research saying in general hematocrit levels <23% increase mortality but

still nothing specific to at what point does oxygenation cease.

[Guest guest]

to the best of my knowledge, the use of artificial heme replacements is

limited to research even in clinical, much less field medicine. I don't even

think that the US/CAN/UK military field medical services are using it right

now.

ck

In a message dated 06/30/11 07:08:53 Central Daylight Time,

summedic@... writes:

Thanks doc, and Gene, this has been a great topic. Does anyone have

any information on the use of artificial blood, possibly in the field?

Sent from my iPhone

McGee, EMT-P

> from a field perspective, giving fluids to temporarily maintain B/P and

CPP

> is just that....a temporary effort.

>

> from a clinical perspective, I've seen many folks 'walking, talking and

> potty trained' with H/H of 5g/15%- they do tend to decompensate rapidly

when

> stressed. I think that the still ambulatory patient with the lowest

reading

> was around 3.9/11%....

>

> any time there is leaking from the vascular system, fluid replacement is

> only the first step. The critical step is fixing the leak- In trauma,

this is

> generally with transfusion followed by surgery (or surgery followed by

> transfusion, depending on the situation). For other conditions, other

fixes

> may apply....for example, relieving a chronic bladder neck obstruction

with a

> Foley catheter may result in a profound diuresis- possibly over 3

> liters/hour- appropriate fluid replacement (baseline plus 3/4ths of the

hourly

> output x 24 hours, then baseline plus 1/2 hourly output for 24 hours,

etc) and

> tincture of time will fix this problem.

>

> ck

>

>

> In a message dated 06/30/11 01:04:45 Central Daylight Time,

> txladymedic@... writes:

>

> I've looked to see if there was an article or study on the internet

saying

> at what hematocrit level does oxygenation cease and can't find one. I

> found research saying in general hematocrit levels <23% increase

mortality but

> still nothing specific to at what point does oxygenation cease.

>

> [Non-text portions of this message have been removed]

>

>

[Non-text portions of this message have been removed]

------------------------------------

Yahoo! Groups Links

[Guest guest]

I asked because I recently took a TCCC course and they mentioned it for military

use. I am not sure if they were just looking into it or what.

Sent from my iPhone

McGee, EMT-P

> to the best of my knowledge, the use of artificial heme replacements is

> limited to research even in clinical, much less field medicine. I don't even

> think that the US/CAN/UK military field medical services are using it right

> now.

>

> ck

>

>

> In a message dated 06/30/11 07:08:53 Central Daylight Time,

> summedic@... writes:

>

> Thanks doc, and Gene, this has been a great topic. Does anyone have

> any information on the use of artificial blood, possibly in the field?

>

> Sent from my iPhone

> McGee, EMT-P

>

>

>

> > from a field perspective, giving fluids to temporarily maintain B/P and

> CPP

> > is just that....a temporary effort.

> >

> > from a clinical perspective, I've seen many folks 'walking, talking and

> > potty trained' with H/H of 5g/15%- they do tend to decompensate rapidly

> when

> > stressed. I think that the still ambulatory patient with the lowest

> reading

> > was around 3.9/11%....

> >

> > any time there is leaking from the vascular system, fluid replacement is

> > only the first step. The critical step is fixing the leak- In trauma,

> this is

> > generally with transfusion followed by surgery (or surgery followed by

> > transfusion, depending on the situation). For other conditions, other

> fixes

> > may apply....for example, relieving a chronic bladder neck obstruction

> with a

> > Foley catheter may result in a profound diuresis- possibly over 3

> > liters/hour- appropriate fluid replacement (baseline plus 3/4ths of the

> hourly

> > output x 24 hours, then baseline plus 1/2 hourly output for 24 hours,

> etc) and

> > tincture of time will fix this problem.

> >

> > ck

> >

> >

> > In a message dated 06/30/11 01:04:45 Central Daylight Time,

> > txladymedic@... writes:

> >

> > I've looked to see if there was an article or study on the internet

> saying

> > at what hematocrit level does oxygenation cease and can't find one. I

> > found research saying in general hematocrit levels <23% increase

> mortality but

> > still nothing specific to at what point does oxygenation cease.

> >

> >

[Guest guest]

,

Well, of course you have described the great dilemma that we face in attempted

resuscitation of these patients. You are entirely correct. All of these things

come into play.

Obviously, when the Hct gets too low, there will not be adequate oxygen carrying

capacity in the blood. There are no definitive studies that I can find that

define the limits of Hct in terms of being able to supply adequate oxygen to the

tissues.

I think that as prehospital providers, we should concentrate on CPP. Now, that

may conflict with our other concepts of fluid resuscitation, and there is a

definite conflict between the concept of permissive hypotension and adequate

CPP.

Obviously at some point fluid resuscitation will become a negative for survival.

In isolated thoracic penetrating injury, penetrating abdominal injury, AAA, and

so forth, it's really up for grabs what we ought to do in fluid resuscitation.

We know that in isolated penetrating abdominal and thoracic injuries, too much

fluid can be bad. But we also know that unless the brain is perfused

adequately, brain injury will result, and no matter what we do to the rest of

the body, the patient will not recover with a meaningful life.

So we balance what we do.

The ability to see the BIG PICTURE is the difference between a poor medic and a

master medic. Let's all work to be master medics.

GG

Re: Question regarding fluid resuscitation

Gene,

I was not taught in Paramedic school but that was a little bit ago. I was taught

the concept in CCEMT-P, TCCC and PHTLS/ITLS.

You can put all the NON-oxygen carrying volume you want but there comes a point

that you have a lot of fluid and only one little cell trying to oxygenate the

body and brain. I am also with you on vasopressors, they have there place but

not when it comes to an empty tank.

There is at least one study out there saying low hematocrit through hemodilution

increases ICP and causes a worsened neurological outcome.

So you can give your patient fluids to help meet your CCP and MAP levels and

help decrease the ICP. However, Because you've had a loss of volume through a

bleed somewhere, you give the fluids which causes hemodilution which causes low

hematocrit which causes increased ICP so you are potentially causing the very

thing which you are trying to avoid or help treat in the first place. The

answer? Blood and/or blood products. You can do many things to help with the

increased ICP issues: good oxygenation to assist your lone cell trying to

oxygenate, raise the head of the bed slightly which can sometimes decrease the

ICP, hypothermia is sometimes helpful, watch your glucose levels, mannitol,

steroids (although research is showing that steroids should not be used in

TBI),blood and/or blood products, AND adequate sedation and pain treatment.

I've looked to see if there was an article or study on the internet saying at

what hematocrit level does oxygenation cease and can't find one. I found

research saying in general hematocrit levels <23% increase mortality but still

nothing specific to at what point does oxygenation cease.

Now that I have put in my two cents worth I'll go back to my bat cave....

>

> > For the last few years, fluid resuscitation of trauma patients has been

aimed at maintaining a systolic BP of 80-90 mm Hg. The concept is that of

" permissive hypotension " based upon hydrostatic concerns about the effects of

heightened hydrostatic pressures in the fact of internal bleeding. It has been

postulated that increased hydrostatic pressures will dislodge clots that have

been formed as a natural response to injury, and that increased fluid volumes

will dilute clotting factors and lead to increased bleeding. These concepts are

valid.

> >

> > However, I propose that this concept fails to take into consideration one

vital aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

> >

> > There are two components of blood pressure: the systolic and diastolic

readings. Systolic pressure represents hydrostatic pressure, and diastolic

pressure represents the degree of vasoconstriction. This is an

oversimplification, but it is

> >

> > basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg

does not insure adequate CPP.

> >

> > In order to figure CPP, one must first determine mean arterial pressure

(MAP) and estimate the intracranial pressure (ICP). Intracranial pressure cannot

be monitored in the field, but can be estimated based upon clinical

observations.

> >

> > The formula for CPP is this: CPP = MAP - ICP.

> >

> > MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

> >

> > Normal patients without head injuries, at rest, have an ICP of from around 5

to 15 mm Hg. This can vary depending upon posture. For example, if a patient who

is supine suddenly stands up, his ICP will fall, and if he is dehydrated or

taking antihypertensives that antagonize alpha-1 vasoconstriction, he can become

dizzy or even faint. Conversely, when one coughs or sneezes, ICP spikes, but

only for a few seconds.

> >

> > With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

> >

> > Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg,

then MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In

fact, a CPP of 53 is close to the limit for survival.

> >

> > And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

> >

> > These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

> >

> > So my question is this: How many of you who are EMS educators use this in

your teaching? How many of you who are Paramedics have had this training and

understand these concepts?

> >

> > Are we doing enough to educate our medics to the basics of brain perfusion

with the current guidelines about fluid resuscitation?

> >

> > Gene Gandy, JD, LP, NREMTP

> > PERCOMONLINE.COM

> > Tucson, AZ

> >

> > .

> >

> >

[Guest guest]

,

Well, of course you have described the great dilemma that we face in attempted

resuscitation of these patients. You are entirely correct. All of these things

come into play.

Obviously, when the Hct gets too low, there will not be adequate oxygen carrying

capacity in the blood. There are no definitive studies that I can find that

define the limits of Hct in terms of being able to supply adequate oxygen to the

tissues.

I think that as prehospital providers, we should concentrate on CPP. Now, that

may conflict with our other concepts of fluid resuscitation, and there is a

definite conflict between the concept of permissive hypotension and adequate

CPP.

Obviously at some point fluid resuscitation will become a negative for survival.

In isolated thoracic penetrating injury, penetrating abdominal injury, AAA, and

so forth, it's really up for grabs what we ought to do in fluid resuscitation.

We know that in isolated penetrating abdominal and thoracic injuries, too much

fluid can be bad. But we also know that unless the brain is perfused

adequately, brain injury will result, and no matter what we do to the rest of

the body, the patient will not recover with a meaningful life.

So we balance what we do.

The ability to see the BIG PICTURE is the difference between a poor medic and a

master medic. Let's all work to be master medics.

GG

Re: Question regarding fluid resuscitation

Gene,

I was not taught in Paramedic school but that was a little bit ago. I was taught

the concept in CCEMT-P, TCCC and PHTLS/ITLS.

You can put all the NON-oxygen carrying volume you want but there comes a point

that you have a lot of fluid and only one little cell trying to oxygenate the

body and brain. I am also with you on vasopressors, they have there place but

not when it comes to an empty tank.

There is at least one study out there saying low hematocrit through hemodilution

increases ICP and causes a worsened neurological outcome.

So you can give your patient fluids to help meet your CCP and MAP levels and

help decrease the ICP. However, Because you've had a loss of volume through a

bleed somewhere, you give the fluids which causes hemodilution which causes low

hematocrit which causes increased ICP so you are potentially causing the very

thing which you are trying to avoid or help treat in the first place. The

answer? Blood and/or blood products. You can do many things to help with the

increased ICP issues: good oxygenation to assist your lone cell trying to

oxygenate, raise the head of the bed slightly which can sometimes decrease the

ICP, hypothermia is sometimes helpful, watch your glucose levels, mannitol,

steroids (although research is showing that steroids should not be used in

TBI),blood and/or blood products, AND adequate sedation and pain treatment.

I've looked to see if there was an article or study on the internet saying at

what hematocrit level does oxygenation cease and can't find one. I found

research saying in general hematocrit levels <23% increase mortality but still

nothing specific to at what point does oxygenation cease.

Now that I have put in my two cents worth I'll go back to my bat cave....

>

> > For the last few years, fluid resuscitation of trauma patients has been

aimed at maintaining a systolic BP of 80-90 mm Hg. The concept is that of

" permissive hypotension " based upon hydrostatic concerns about the effects of

heightened hydrostatic pressures in the fact of internal bleeding. It has been

postulated that increased hydrostatic pressures will dislodge clots that have

been formed as a natural response to injury, and that increased fluid volumes

will dilute clotting factors and lead to increased bleeding. These concepts are

valid.

> >

> > However, I propose that this concept fails to take into consideration one

vital aspect of trauma care, that of adequate perfusion of the brain. Cerebral

perfusion pressure (CPP) is the measure of brain perfusion, and it must be

maintained at a level of 80 mm Hg or better. Studies show that when a patient's

CPP is maintained at that level, there is a 35% improvement in outcomes, whereas

lower CPPs result in poorer outcomes.

> >

> > There are two components of blood pressure: the systolic and diastolic

readings. Systolic pressure represents hydrostatic pressure, and diastolic

pressure represents the degree of vasoconstriction. This is an

oversimplification, but it is

> >

> > basically accurate. Simply maintaining a systolic pressure of 80-90 mm Hg

does not insure adequate CPP.

> >

> > In order to figure CPP, one must first determine mean arterial pressure

(MAP) and estimate the intracranial pressure (ICP). Intracranial pressure cannot

be monitored in the field, but can be estimated based upon clinical

observations.

> >

> > The formula for CPP is this: CPP = MAP - ICP.

> >

> > MAP can easily be computed by this formula: (1/3 pulse pressure) + diastolic

pressure. Thus, a patient with a BP of 140/80 will have a pulse pressure of 60.

One-third of 60 is 20, and added to the diastolic pressure of 80, results in a

MAP of 100.

> >

> > Normal patients without head injuries, at rest, have an ICP of from around 5

to 15 mm Hg. This can vary depending upon posture. For example, if a patient who

is supine suddenly stands up, his ICP will fall, and if he is dehydrated or

taking antihypertensives that antagonize alpha-1 vasoconstriction, he can become

dizzy or even faint. Conversely, when one coughs or sneezes, ICP spikes, but

only for a few seconds.

> >

> > With a MAP of 100, and an estimated ICP of 15, the CPP would be 85, which is

fine. But if the BP is, for example, 90/50, then the MAP is only 63. [1/3 pulse

pressure (40) = 13. Diastolic pressure of 50 + 13 = 63, the MAP.

> >

> > Using the formula CPP = MAP - ICP, if one assumes a normal ICP of 10 mm Hg,

then MAP (63) - estimated ICP (10) = 53, far below the target CPP of 80. In

fact, a CPP of 53 is close to the limit for survival.

> >

> > And this is in a patient without a head injury. Given a patient with rising

intracranial pressure, it becomes obvious that a higher MAP is needed to

adequately perfuse the brain.

> >

> > These concepts are taught in the traumatic brain injury courses, but not

emphasized, I fear, in paramedic training.

> >

> > So my question is this: How many of you who are EMS educators use this in

your teaching? How many of you who are Paramedics have had this training and

understand these concepts?

> >

> > Are we doing enough to educate our medics to the basics of brain perfusion

with the current guidelines about fluid resuscitation?

> >

> > Gene Gandy, JD, LP, NREMTP

> > PERCOMONLINE.COM

> > Tucson, AZ

> >

> > .

> >

> >