MovieChat Forums > Hector and the Search for Happiness (2014) Discussion > Air pressure and the cancer patient conf...

Air pressure and the cancer patient confuses me

posted 10 years ago by hal-9010
11 replies | jump to latest

* * * MINOR SPOILERS * * *

I do not think it is correct when they lower the altitude to ease the pressure in order to comfort the cancer patient onboard the plane.

Firstly: airplanes are pressurized vehicles and so the altitude is in principle irrelevant for the travelers and the pressure inside the cabin.

Secondly: it is true that airplanes differ their cabin pressures during travel for various reasons and does not hold a sea level pressure, as many perhaps assume. However, the minimum pressure is never below that of which it would be at about 2 000 m altitude. And since a typical flight altitude is well above 10 000 m there is NO WAY the plane would go so far down to below 2000 m just to accomodate an ill fated passenger.

Thirdly: wouldn't less pressure benefit the patient and so the plane would have to increase its altitude and not decrease as he asked?

Fourthly: a plane is a PRESSURIZED VEHICLE so there is no need to change altitudes, the captain could adjust the cabin pressure to anything at will by turning a few nobs and without risking safe flight routines ...

Tell me, am i wrong ?

.... and a last note: in Africa he was just a psychiatrist unable to assist medically. On the plane he was... now trained enough medically to assist a brain tumor patient. I guess, "where there is a will" there is happiness.

___________
** I am normally not a praying man, but if you are up there, please save me Superman **

[–] starcraftbw88 10 years ago

Yeah, movie sucked; psychiatrist turned into a neurosurgeon on the plane. And African villages just burst out into parties whenever a white dude shows up. There are so many things wrong with the movie.

[–] filmfancy 10 years ago

There are so many things wrong with the movie.

Like why is a dying woman travelling and taking a plane when her sister could have come to visit her instead. If the sisters are that close, why would the well sister allow the sick one to travel?

And all the pieces matter (The Wire)

[–] benman46 10 years ago

A psychiatrist is a medically trained doctor who specialises on the brain. So he would know exactly what to do in the case of a patient with a brain tumour.

[–] hal-9010 10 years ago

he is no neurosurgeon, but you are right. He must be trained on some level in the field. Did not realize this. Thanx. It explains "my last note".

___________
** I am normally not a praying man, but if you are up there, please save me Superman **

[–] leed8362 10 years ago

Not sure where you learned this? Try researching before. http://www.cancer.net/blog/2014-07/traveling-cancer
I'm not a doctor, but a certified open water diver. Watching the movie for the first time and before hearing Hector's solution, my first guess was to lower the altitude. The pressure can effect the air spaces in your body. You can feel discomfort in the ear or sinuses in a "reverse squeeze". Your body's air space doesn't have problem with ascent (ear popping). To avoid decompression sickness, scuba divers, depending on the descent, must wait a certain period ascending to the surface and air travel.

I'm not sure what the differences are in psychiatry in the US and the UK. But generally they need to know biochemistry, neuroscience, biology, pharmacology and medicine. Dressing a bullet wound isn't something Hector would be practiced with.

[–] hal-9010 10 years ago

Not sure why you think I am wrong in my science?

I am not contradicting what your link is stating and advising, nor do my words go against your experience as a diver. Naturally, pressure effects our fluids especially and so we can feel discomfort when such changes in pressure occurs; be it water or air. However, what I do say is that an airplane is a pressurized vehicle and so can manually adjust its inside pressure despite on how the outside pressure may be (to a certain limit of course). This is the whole point of a pressurized vehicle. A solution you yourself would go for in the case of catching divers' disease. I very much doubt you would ask them to throw the "Diving chamber" overboard after entering it, in a way, I think, this is what our hero asks the plane captain to do.

The reason we still experience popping in our ears etc when flying is that the in-cabin pressure indeed changes while either taking off or landing. However, once the plane reaches an altitude of about 2000 meters the in-cabin pressure is maintained more or less constant. In other words, there will be no change in the inside pressure if the plane changes its altitude, as our hero seem to believe.

It would have to go below 2000 meters to really mean anything – however, I am absolutely sure that the Captain would never go below this altitude on a long distance flight. If the patient experiences displeasure then the Captain of the plane can change the inside pressure at will to (in principle) sea level pressure without changing the altitude.

So just to recap my position: Naturally, change in pressure can create discomfort and so also relief. However, plane travellers are unaffected to the outside pressure when its altitude is above 2000 meters. Commercial airlines usually fly at above 10 000 meters and so the solution for our patient is to ask the Captain to change the inside pressure (which he can by the turn of a switch) rather than to fly dangerously below 2 000 meters on the rest of the flight.

And yes, I think your point about psychiatry makes perfect sense. 😃

___________
** I am normally not a praying man, but if you are up there, please save me Superman **

[–] Redwood-George 10 years ago

Commercial airliners typically pressurize the cabins to 8,000ft (roughly 2,500m) while they fly at 30,000ft (10,000m). The pressurization system in a plane can't significantly increase the pressure above that - it's a differential between internal and external pressure. Flying at 30,000 ft and pressurizing the plane to sea level would put quite a bit more stress on the structure of the jet.

For the sake of the movie, if they wanted to increase the pressure to 4,000ft they'd probably need to fly below 20,000ft. Not only would this increase drag (burning more fuel) but they'd also be exposed to more weather and turbulence. The captain could choose to fly at a lower altitude but he'd probably catch grief from flight operations for routing the plane so inefficiently. (Of course the counter-argument is that it was probably more economical to continue flying at a lower altitude rather than turning the plane around or landing at a nearby airport, delaying the flight)

[–] hotbody805 9 years ago

The American Society of Clinical Oncology noted that patients who have a brain tumor may not be advised to fly due to a risk of increased swelling in their brains, or cerebral edema.

During flight, air pressure and oxygen levels change when the plane reaches high altitudes. The swelling of the brain increases pressure inside the skull. Symptoms of increased intracranial pressure include headache, decreased consciousness and vomiting.

[–] hal-9010 9 years ago

Of course, but this is not what the OP is talking about though.

Once onboard the plane and once the plane is above 2000 meters in altitude, the pressure and oxygen levels are maintained more or less constant. So when the plane is already at those levels (like in this movie) it makes no difference at all if the plane would increase or decrease its altitude... only if the plane again would go below 2000 meters a difference in the pressure would be felt: which a commercial airline would not do (normally it is about 10000 metres).

However, as the OP argues; the captain can in principle manipulate the cabin pressures to accommodate our patient. However, not by change of altitude, but by increasing the air pressure mechanically inside the vessel.... effectively meaning that although our heroes intention is medically sound, his basic recommendation to the Captain is nonsense.

___________
** I am normally not a praying man, but if you are up there, please save me Superman **

[–] Film_monger 9 years ago

Internal pressure can be adjusted to a great extent, but if you have ever flown with a sinus blockage, you would experience an intense pain of the sinus ballooning. It is a debilitating pain far worse than even a class 10 migraine.
The aircraft typically flies about 28-35 thousand feet. At that altitude, the cabin altitude would be set at about 6000-8000 feet. They could mitigate some of the pressure with the cabin air controls but it puts an enormous strain on the pressure cabin. The lower altitude is less efficient but could easily be done for a medical emergency. If they flew at 10-15 thousand and set the cabin to 4000 feet, then the patient would gain an incredible amount of relief.
I am retired from the air force so I can attest to these facts. It was a perfectly reasonable thing to do that would only have meant a bit more fuel burned and flying through a bit more air traffic.

[–] hal-9010 9 years ago

Thanx for this insight. I makes sense that they would be able to manipulate the in cabin pressure to a greater extend the lower the outside pressure would be, so in fact both solutions would apply. Thanx.

___________
** I am normally not a praying man, but if you are up there, please save me Superman **