Listening to the story about the death of David Bloom of MSNBC made me concerned. They say the many hours in the hummvee, and the associated lack of his ability to stretch and move around, contributed to the "embolism. This also reminded me of a case about a year back where a lady also died of an embolism on an airliner. The contributing factor was that she was on a long trip and could not, or did not move around…
Perhaps I just need something to worry about, but I sometimes make long trips in the confines of my SR20. Well, I cant get up and walk around, and I can barely stretch so I am wonderin . . . Is there something, or some type of stretching that can be done to minimize the risk of embolisms while confined to a “flight” position for many hours. Is there a doctor in the house?
Unless you have a medical condition already, I think you would run out of fuel before you were in a SR 20 long enough to have a problem.
I am no doctor but this is what I have been told.
Mason
Dennis,
If you ever get a blood clot in your legs (anywhere)…YOU KNOW! Long before you form a clot large enough to break off and kill you…the pain leading up to that point is ‘tough stuff’. You’ll get the heads up if something is wrong.
I had 3 major clots in my left leg in '96 after double hip replacement surgery. The 18 hrs. leading up to the ‘emergency’ emergency room visit were unbearable after major doses of percacet and valium.
Bloom was told 8-10 hours before to get out of there and seek medical treatment…Apparently he continued on.
Sitting in a Cirrus, your legs are stretched out, clots behind the knee can/will form if your leg(s) stays bent +45 degrees or more for a very long time.
Plus my bladder and my comfort level need to get down every 2.5 hrs. or so. It is then convenient to top off the fuel too.
A quick MedLine search for pertinent medical literature suggests that deep vein thrombosis (DVT) and/or pulmonary embolism (PE) is not likely in shorter flights (i.e. less than 5-6 hours).
Suggested treatment/prevention has included: compression stockings, aspirin, foot exercises (without uniform consensus on effectiveness).
I will try to include a MS Word document attachment with a sampling of some of the abstracts, for those interested in more details.
Richard Ward, MD (pathologist, with NO claim that coagulation is my area of expertise)
Of course in an airliner you are generally pressurized to 8000’. We often fly higher, and experience lower blood oxygen levels than you’d get in an airliner (at 8000’ I typically have a blood-ox of 93+, but up high on O2 I usually settle for a level of 90-91). I don’t know if that would make you more or less likely to experience coagulation.
-Curt
Rich Ward basically said it best. You are at litle risk for the durantion of flight between fuel stops. Plus you move your legs more as a pilot to work the rudder pedals.
Hypoxemia and altitude have no direct effect on coagulation but many folks at high altitude become dehydrated and that CAN make your blood clot a little faster.
David Bloom was pending a lot of time inside a tank. Most of us will not experience THAT DEGREE of confinement.
But doesn’t altitude make your fingers and feet swell. What effect does that have?
The swelling that occurs with altitude is a function of immobility and reduced airpressurre outside your body. Kinda like what would happen if you took an inflated balloon to 10,000 feet. The air inside would expand over time and “swell” the balloon until it popped. The same can happen at extreme altitudes with your body which is why astronauts need pressure suits.
But that has no effect on blood clotting.
So, you are saying that I wouldn’t get an embolism, but if I go high enough and for long enough, I might explode!
What will my wife think?
In reply to:
The swelling that occurs with altitude is a function of immobility and reduced airpressurre outside your body. Kinda like what would happen if you took an inflated balloon to 10,000 feet. The air inside would expand over time and “swell” the balloon until it popped. The same can happen at extreme altitudes with your body which is why astronauts need pressure suits.
Brian,
My understanding is there are 2 reasons you may need a pressure suit; either because the partial pressure of oxygen is insufficient, or because G-forces will move your fluids away from your brain without it. I didn’t think control of swelling was an issue. Gases expand with altitude but liquids don’t.
-Curt
That is why they limit the service ceiling of the Cirrus to 17,500. They do not want you to explode.
In reply to:
What will my wife think?
She might think you should upgrade to a `22! (as long as you are adequately insured) [;)]
Dennis,
It’s a common misconception (promoted by several otherwise entertaining science fiction movies, including the 1981 Sean Connery film http://us.imdb.com/Title?0082869Outland) that you would explode if exposed to vacuum.
For an excellent explanation of why this is not the case, see http://www.badastronomy.com/mad/1999/space_feel.htmlthis link from Phil Plait’s informative and entertaining http://www.badastronomy.com/Bad Astronomy web site.
I actually demonstrate this to my introductory astronomy students. I place both an open beaker of water and an orange (which, like you and me, has a skin and is filled with fluid) side by side in a vacuum jar. I then evacuate most of the air with a vacuum pump. At sufficiently low pressure the water in the beaker boils (at room temperature!). The orange, however, is unaffected (and is just as juicy when removed from the vacuum jar and sliced open).
Cheers,
Roger
In reply to:
That is why they limit the service ceiling of the Cirrus to 17,500. They do not want you to explode.
The “service ceiling” of the SR22 is much higher that 17,500, that being the altitude at which the airplane can manage only a 50 FPM climb rate. The maximum authorized altitude for the SR22, a POH limit, is 17,000 feet.
Curt:
Your body has a mixture of gas and liquids in a variety of organs including your blood, intestines and joints. Just like divers can get the bends from too much pressure change with depth, high altitude flyers can get the bends too for the same reason: as outside air pressure drops, internal body gas pressures do not initially. Over time nitrogen will try to “bubble” out of your blood and joint etc. and produce the bends as well. If it were ONLY G forces and Air pressure for breathing we were worried about, then astronauts would only have to were a G suit on their legs and a pressure mask on their face. The whole body has to be protected in those environments.
Don:
While deep vein thrombosis (DVT) may result in clinical symptoms, many are asymptomatic.
One of the abstracts cited in the attachment in my earlier posting included the following in its summary: “We conclude that symptomless DVT might occur in up to 10% of long-haul airline travellers”.
In reply to:
The maximum authorized altitude for the SR22, a POH limit, is 17,000 feet.
Gordon,
I’m asking (because I really don’t know)… is that a maximum authorized altitude, or a maximum demonstrated altitude? IOW… is it in any sense contrary to the FARs to climb higher than that?
- Mike.
My copy of the SR22 POH says “maximum operating altitude”. I don’t see a lot of wiggle room. I would treat that just like “maximum gross weight”. By the way the SR20 “maximum operating altitude” is 17,500 so there is some factor other than the ability to climb which went into this number.
In reply to:
is that a maximum authorized altitude, or a maximum demonstrated altitude? IOW… is it in any sense contrary to the FARs to climb higher than that?
I didn’t have the POH with me when I posted, but I do now. The POH refers to it as the “Maximum operating altitude.” It is 17,000 feet MSL.
I goofed on the definition of “service ceiling.” It is that altitude at which the maximum ROC is 100 feet/minute, not 50. (Could have something to do with the fact I’m turning 50 in three weeks!) It is the “practical upper limit for steady, level flight.”
I think the only FAR you’d violate going past 17,000 would be that requiring conformance with the POH. Altitudes requiring specific oxygen delivery systems don’t kick in until the you’re into the 20’s, except I believe at 18K and higher you can’t use a cannula.
Art, The factor that went into the number is the fact that when you get to 180 there are different certification requirements. Cirrus chose not to certify the airplane for altitudes above 17500, probably for economic reasons.
I agree that the limit is real and flying above 17500 is in violation of the operating limitations of the aircraft.