Pikes Peak CO

1
Pikes Peak CO

• Fatemeh, Lara, Ryan, Kevin
• Bio 349
• Spring 2007

2
The Question
Your lab partner Scott went to Colorado during
Spring break. While there, he drove to the top of
Pikes Peak to walk around and see the sights,
but had to sit down to rest three times. The last
time was in the weather station, where he glanced
at the barometer. It read 450 mmHg. Complete the
table of cardiopulmonary parameters at sea level
and explain your predictions for the direction of
change (increase, decrease, no change) that take
place by the time Scott enters the weather
station, as compared with the values that he had
at home in Bellingham.
3
Gas Exchange is by Diffusion
The net rate of diffusion is largely influenced
by the pressure gradients (PO2 and PCO2 across
the respiratory membrane).
Alveolar air does not contain the same amount of
O2 and CO2 as atmospheric air because of the
anatomic dead air space.
At equilibrium, alveolar PO2 will equal blood PO2.
4
Diagnosis?

• Scott is possibly experiencing moderate Acute
  Mountain Sickness (AMS) due to his desire to sit
  down to control dizziness, fatigue, nausea he may
  be experiencing.
• AMS occurs commonly above altitudes of 8000 ft.
• Pikes Peak maximum elevation is 14,115 ft.

5
Need to know

• Atmospheric air contains 21 O2, therefore PO2
  .21 x atmospheric pressure X mm Hg.
• But atmospheric air mixes with residual air in
  the anatomic dead air space, so alveolar PO2 is
  less
• Hemoglobin O2 saturation depends on the rate of
  diffusion at alveoli
• This, in turn, depends on arterial PO2
• Changes in effort during ventilation effort may
  be accomplished by a change in rate and/or a
  change in tidal volume
• If minute respiratory changes in an effort to
  maintain normal O2 levels, CO2 levels will also
  change
• With an effect on pH

6
Bellingham vs. Pikes Peak
7
Whats Happening

• At sea level, carbon dioxide acts on the
  peripheral chemoreceptors of the carotid arteries
  and aortic arch and on central chemoreceptors in
  the respiratory center of the medulla.
• When ascending up a mountain, the barometric
  pressure and partial pressure of oxygen
  decreases.
• When oxygen becomes less concentrated, we have a
  greater need for ventilation.

8
Consequences

• If Scott cannot acclimatize, the combination of
  high altitude and low air pressure will cause
  fluid to leak from the capillaries causing fluid
  build up in the lungs and brain.
• Fluid build up in the lungs is termed High
  Altitude Pulmonary Edema (HAPE) and fluid build
  up in the brain is termed High Altitude Cerebral
  Edema (HACE).

9
Prevention

• To prevent AMS, one should decrease activity
  (rest), increase fluid intake to prevent
  dehydration, and descend.
• Before climbing, one should plan acclimatization
  camps at different elevations.

10
Analogy

• Pressure of an upcoming exam
• The pressure gets worse as the exam date moves
  closer which forces you to be more productive and
  study and learn more
• This is analogous to the increase in altitude.
• As the altitude increases, the amount of oxygen
  in the air decreases, placing stress on your
  body, which causes your body to work harder to
  carry more oxygen to your tissues.

11
References

• http//www.destination360.com/north-america/us/col
  orado/pikes-peak.php
• http//www.lib.mcg.edu/edu/eshuphysio/program/sect
  ion4/4ch6/s4ch6_21.htm
• http//www.med.howard.edu/anatomy/gas/wk7/Barorece
  ptor.gif
• http//www.biosci.ohio-state.edu/patches/eeob410/
  respiratorylecture.htm
• http//www.high-altitude-medicine.com/AMS-medical.
  html
• http//www.alanarnette.com/alan/everest2006.php
• http//www.coloradoguy.com/williams-waldo-canyon.h
  tm
• http//www.bio.davidson.edu/courses/anphys/1999/Yu
  si/adaptation.html
• http//www.ilo.org/encyclopedia/?dnd857100051pr
  evDoc857000009
• http//www.altitudephysiology.org/oxygenphysiology
  /everestfacts/oxygencalculatorhighaltitude.htm
• http//www.bio.davidson.edu/courses/anphys/1999/Yu
  si/adaptation.html
• http//www.healthatoz.com/healthatoz/Atoz/common/s
  tandard/transform.jsp?requestURI/healthatoz/Atoz/
  ency/respiratory_alkalosis.jsp

12
References

• http//www.healthsystem.virginia.edu/Internet/Anes
  thesiology-Elective/airway/ventilation.cfm
• http//www.brooksidepress.org/Products/Military_OB
  GYN/Library/MilitaryTexts/GMOManual/GMOManual.htm
• http//www.lakesidepress.com/pulmonary/papers/eq/e
  qal.html
• http//www.lakesidepress.com/pulmonary/papers/eq/e
  qal.html
• http//jp.physoc.org/cgi/content/full/546/3/921
• http//www.portfolio.mvm.ed.ac.uk/studentwebs/sess
  ion4/61/altdet.htm
• http//www.lakesidepress.com/pulmonary/papers/eq/e
  qal.html
• http//hypertextbook.com/facts/2001/LaurenCalabres
  e.shtml
• http//www.altitudephysiology.org/oxygenphysiology
  /everestfacts/oxygencalculatorhighaltitude.htm