Nitrox question

[sphyrnidus]

Suits me, but still a long way from 100%...

 

[Polari]

But this statement is about 100% Oxygen. Recreational mixtures do not exceed 36%.

When i said before that:

If this law is correct then it can be 6 times more.I know is not much if you compare it with the oxygen on hemoglobin but is still almost 1/10th of the total.

I calculate that based on air (21%)
Now if i calculate it based on 36% or 40% you understand that it will be a significant part of the total oxygen.It would be like 1/4 of the total.
So you said that your a doc.Please go back ,read Hernys law, do the mathematical equations and then come back and if you dare please repeat this:

There is actually very little oxygen dissolved in the blood. Yes it's the oxyhemoglobin that does the trick.
And yes I doc

I dont like to sound arrogant or anything.I dont even finish the school not do i have any relation with the medical world.But there so many docs here and not even one can read a simple law that a 10 years old kid easy can understand ?
If iam wrong then please let me know by laws or by mathematical or experiments not by just what you heard.I will then say ok i was wrong and continue my study based on the proof you provide.

 

[freewillie]

I've never said the law was incorrect. What I argued was the amount of oxygen that could dissolve into blood plasma was not clinically significant to deliver enough oxygen to reduce PhatDiver's skipped heart beats.

We are arguing apples and oranges. The law states that you can dissolve more gas with increased pressure and increased gas concentration. That is true. But body physiology is such that the amount of oxygen that is delivered and the clinical difference that it makes is not significant. They are two different principles.

For the last example of being able to dissolve enough oxygen to be effective at 3 ATM and at 100% oxygen for hyperbaric therapy may be true under those circumstances. Your equations are correct. But, divers do not dive at 100% oxygen. They dive at no more than 36%-40% oxygen. We are also stipulating that the OP is diving at depths above 65 Ft at the deepest. At 3 ATM you are closer to 100 ft., a depth that is greater that what we are experiencing. You are invoking variables that don't pertain to the actual situation we are discussing.

The other notion is does the increased oxygen in plasma make a clinical difference. Can you get more tissue oxygen. While you have successfully stated under what circumstances you can achieve those levels the conditions required are not applicable to the actual conditions experienced. It's like going to a ski resort in the summer. You may need the big ski parka during the winter, but during the summer the same conditions do not apply even for the same location.

We can think of it in other way. The question of oxygen is a quantitative volume, how much do you need to make a difference? It is like arguing the difference in temperature and heat of a coffee cup and a bath tub. Both the coffee cup and the bath tub might have the same temperature of water but the amount of thermal heat is much greater in the bath tub compared to the coffee cup. The same would be true for plasma oxygen. You are trying to deliver a coffee cup of heat but that is not the same as a bath tub of heat. If that makes sense.

 

[Polari]

For the last example of being able to dissolve enough oxygen to be effective at 3 ATM and at 100% oxygen for hyperbaric therapy may be true under those circumstances. Your equations are correct. But, divers do not dive at 100% oxygen. They dive at no more than 36%-40% oxygen. We are also stipulating that the OP is diving at depths above 65 Ft at the deepest. At 3 ATM you are closer to 100 ft., a depth that is greater that what we are experiencing. You are invoking variables that don't pertain to the actual situation we are discussing.

Thank you for your time but i still disagree.I really learn a lot by this thread and hope my understanding gets more clear.Maybe iam not doing correct my maths.
.Lets see.I will try to do the math and please advise.

3 ATM is 20meter.OP depth is at 3ATM and sometimes 100ft or 33meters or 4ATM

Po2 =760(at 3 atm)x(EAN0.40%)=912mmHg
That means the volume of dissolved oxygen increases almost 10 times.
So 0.31ml/dl x 9.2 = 2.8ml/dl of blood.

A healthy adult human at rest uses about 6ml of oxygen per dl of circulating blood.

You are trying to deliver a coffee cup of heat but that is not the same as a bath tub of heat. If that makes sense.

As we see from the above example is almost the half the oxygen needed.So this coffee is more like the half of a bath tub

 

[stuartv]

If I may, I think I understand what both of you are saying and maybe I can try to explain it better, in a way that Polari will understand.

Polari, I think what freewillie is trying to say is that the body only USES the oxygen that is attached to hemoglobin. The other oxygen that is dissolved in the blood is just, well, O2 dissolved into a liquid. That O2 that is not attached to the hemoglobin is not used by the body to, for example, feed the heart. That is why it's not significant.

Maybe this helps? If not, pardon me for intruding.

 

[Polari]

The other oxygen that is dissolved in the blood is just, well, O2 dissolved into a liquid. That O2 that is not attached to the hemoglobin is not used by the body to, for example, feed the heart. That is why it's not significant.

copy-paste:
Oxygen is essential to any healing process. Through Hyperbaric Oxygen Therapy (HBOT), the concentration of oxygen dissolved in the bloodstream is raised many times above normal (up to 2000%). Because of this high concentration of oxygen, Hyperbaric Oxygen is used to accelerate the healing process after operations and incidents such as plastic surgery, non healing wound care, burn victims, smoke inhalation victims, many neuralgic, orthopaedic as well as emergency conditions and degenerative diseases. In addition to the blood, all body fluids including the lymph and cerebral-spinal fluids are infused with the healing benefits of this molecular Oxygen. It can reach bones and tissues which are not accessible to the red blood cells, enhance white blood cell function, and promote the formation of new capillary and peripheral blood vessels.
This results in an increased control of infections and faster healing of a wide range of conditions. With HBOT many patients have remained free of opportunistic infections, experiencing relief from fatigue and even maintaining their body weight in the process! Other uses for HBOT are the treatment of certain cardiovascular conditions.
HBOT is also being increasingly used very successfully by sports teams to improve the healing process of injured athletes such as when Beckham and Rooney suffered broken bones in their feet prior to the 2002 and 2006 World Cup, not to mention the usage of Hyperbaric Oxygen and Oxygen Tents by many teams for acclimatization and also injury healing in the recent 2010 world cup series

 

[TSandM]

No, the body can use oxygen dissolved in the plasma just fine. There just isn't enough of it.

If the person has a normal Hb level of 15 g/dl, he will be carrying almost 20 ml/dl of oxygen on the hemoglobin. At sea level and breathing room air, dissolved oxygen (.3 ml/dl) is about 2% of the total. If we take the person to 40% FI02 and down to 4 ATA, that's about 8 times as much dissolved oxygen, or 2.4 ml/dl, which brings the contribution up to 10% of the total oxygen. It's a 12% increase in total available O2. It just isn't going to make a difference. As I mentioned earlier, research shows that normal people (not conditioned athletes) even when exerting do not drop their arterial saturation, which says that the diffusion across the alveolar membranes is fast enough to supply the oxygen requirements of the tissues. Perhaps for an extremely conditioned individual under maximal stress, the extra 12% might make a difference, but for the average diver, it simply isn't going to change anything.

 

[Polari]

If we take the person to 40% FI02 and down to 4 ATA, that's about 8 times as much dissolved oxygen, or 2.4 ml/dl, which brings the contribution up to 10% of the total oxygen. It's a 12% increase in total available O2. It just isn't going to make a difference. As I mentioned earlier, research shows that normal people (not conditioned athletes) even when exerting do not drop their arterial saturation, which says that the diffusion across the alveolar membranes is fast enough to supply the oxygen requirements of the tissues. Perhaps for an extremely conditioned individual under maximal stress, the extra 12% might make a difference, but for the average diver, it simply isn't going to change anything.

Now i can understand it better.
Even that now you made me have more questions If and when you have the time please elaborate on them.

First is the maths.If:
Ptotal: 760(at the current atm)
Po2artial oxygen pressure
0.31ml/dl: The volume of dissolved oxygen in plasma
Fo2: percentage of oxygen

Po2=Ptot.atm x Fo2=> Po2=760.4ATM x 0.40=1216 mmHg
So we have 12 times more oxygen dissolved in blood.
0.31x12=3.72ml/dl

That is 20% of the total (total is in bold because is my next question ) How did you came up with 12% ? Is my calculations wrong?Please let me know where.

On the next question.
This is a statement i will make based on what i learn until now.
The total in our case does not mean much.Why?Because the oxygen used first is the dissolved oxygen in blood.
Now we can see why oxygen dissolved in plasma is so important.
Especially if we calculate only the oxygen needed by tissue not the oxygen total our blood transfers.
We know that our body at rest uses about 6ml of oxygen per dl of circulating blood.
If 3.72ml/dl is 62% of the oxygen we use then on this occasion dissolved oxygen in blood is the primary source of oxygen :shocked2:

I put emoticons cause sometime my writings looks aggressive which it is not the case.

 

[Polari]

A note to whom may interested:
Another reason why the dissolve oxygen in blood is important and so beneficial especially in amounts we saw above is the gradient between the oxygen in blood and tissue.Causing a partial pressure that creates a diffuse oxygen directly to tissue.
Also because the oxygen is in solution it can reach areas where red blood cells may not be able to pass and can also provide tissue oxygenation in the setting of impaired hemoglobin concentration or function

Taken from Book Principles and Practice of wound Care

A nice simple pdf explaining the laws mentioned :
1. Boyle’s Law,2. Dalton’s Law,3. Henry’s Law,4. Graham’s Law

 

[boulderjohn]

From Oxygen Transport - Regulation of Tissue Oxygenation - NCBI Bookshelf

Blood: Plasma and Red Blood Cells

For purposes of discussing oxygen transport by the blood, we will consider blood to be composed of two phases: plasma and red blood cells (RBCs). The fractional volume of blood occupied by RBCs is called the hematocrit, and its value is a little less than 50% in human adults (∼40% for females and ∼45% for males). Oxygen is carried in the blood in two forms: (1) dissolved in plasma and RBC water (about 2% of the total) and (2) reversibly bound to hemoglobin (about 98% of the total).

At physiological PO2 (40 < PO2 < 100 mm Hg), only a small amount of oxygen is dissolved in plasma since oxygen has such a low solubility. At elevated PO2 (breathing 100 % oxygen or during hyperbaric oxygenation), however, the physically dissolved form of oxygen can become significant. Henry's law states that the amount of oxygen dissolved in plasma is directly proportional to PO2...

From http://www.vet.utk.edu/vhms/pdf/Physiology_of_Hyperbaric_Oxygen.pdf

2. Following its entrance into the blood, a certain amount of
oxygen is immediately combined with hemoglobin in the
blood. If the patient is breathing air at sea level most of the
oxygen in the blood is combined with hemoglobin. A very
small amount is dissolved in the plasma.

a. The amount of oxygen carried by hemoglobin
depends on the amount of hemoglobin in the blood.
In general, 100 ml (3.33oz) of blood carries
approximately 20.4 ml of oxygen. Once hemoglobin
is saturated with oxygen, it provides no additional
oxygen for the tissues under hyperbaric conditions.

b. A very small amount of oxygen, not combined with
hemoglobin, is dissolved in the plasma when a patient
breaths air at sea level (1 ATA). Approximately 100 ml
(3.33 oz.) of blood has only 0.31 ml of oxygen in it
at sea level.

Under hyperbaric conditions more oxygen is available
to be dissolved in the plasma governed by Henry’s
Law. For each 100 mmHg increase in the oxygen
pressure in the alveolus another 0.31 ml of oxygen
can be dissolved in the plasma. We can increase the
dissolved oxygen up to 15 times normal by the use of
hyperbaric therapy.