Paso del Agua Negra, Chile – 1997

Chile is a beautiful country, and for altitude research has the added advantages of good, rapid access to high altitude from a baseline at sea level- plus another escape from the cold and dark of January in Northern Europe. Locals consider onions to be effective for AMS! Nevertheless we would not recommend following their example of sticking an onion into the air filter of a car suffering from mountain sickness!
After driving up the coast from Santiago, pausing for a swim at Los Vilos we were based in La Serena and then headed inland and camped just below the Paso del Aqua Negra (4780m). The pass is a border crossing between Chile and Argentina and a tunnel is planned. In the summer it is a desert but the penitentes remaining from the winter snow provide adequate water supply.

Research included transcranial Doppler measurements of middle cerebral artery velocity, showing the effects of hypoxia, carbon dioxide and hyperventilation. The effectiveness of the Gamow bag was shown to be partly due to an increase in inspired CO2. The use of medroxyprogesterone in preventing acute mountain sickness was compared with acetazolamide.

Newspaper Highlights

  • “Doctors take hormone test to tackle Everest” – Birmingham Post 29th March 1993
  • “The Height of femininity” – Evening Mail 29th March 1993
  • “Everest by Hormones” – The Times 30th March 1993

Publications:

  1. Imray CHE, Barnett NJ, Walsh S, Clarke T, Morgan J, Hale D, Hoar H, Mole D, Chesner I and Wright AD. Near-infrared spectroscopy in the assessment of cerebral oxygenation at high altitude. Wilderness and Environmental Medicine 1998; 9: 198-203.
  2. Wright A. Paso del Agua Negra – Chile 1997. Aesculapius 1998; (18): 24.
  3. Beazley M, Hillenbrand P, Johnson B, Forster PJG, Wright AD, Imray CHE and BMRES. Recommended changes in Lake Louise acute mountain sickness (AMS) scoring system. The 11th International Hypoxia Symposium 1999. Hypoxia: Into the Next Millennium. Advances in Experimental Medicine and Biology. Eds. P. Hackett D. Wagner and R. Roach. 1999; 29: 364. Kluwer Academic Publishers.
  4. Bradwell AR, Williams D, Beazley M, Imray CHE and BMRES. Can acute mountain sickness be induced by exercise? The 11th International Hypoxia Symposium 1999. Hypoxia: Into the Next Millennium. Advances in Experimental Medicine and Biology. Eds. P. Hackett D. Wagner and R. Roach. 1999; 29: 368-369. Kluwer Academic Publishers.
  5. Clarke T, Walsh S, Mole D, Harvey T, Morgan J, Brearey S, Imray C and BMRES. Carbon dioxide or oxygen at altitude? Cutaneous, muscle and cerebral oxygenation. The 11th International Hypoxia Symposium 1999. Hypoxia: Into the Next Millennium. Advances in Experimental Medicine and Biology. Eds. P. Hackett D. Wagner and R. Roach. 1999; 29: 373-374. Kluwer Academic Publishers.
  6. Hale D, Walsh S, Clarke T, Harvey T, Cooper M, Brearey S, Bradwell A, Imray C and BMRES. Carbon dioxide or oxygen at altitude? The effect on arterial blood gases at sea level and on acute exposure to altitude. The 11th International Hypoxia Symposium
  7. Hypoxia: Into the Next Millennium. Advances in Experimental Medicine and Biology. Eds. P. Hackett D. Wagner and R. Roach. 1999; 29: 385-386. Kluwer Academic Publishers.
  8. Hillenbrand P, Beazley M, Forster PJG, Milles JJ, Clayton RN, Wright AD, Imray CHE and BMRES. A randomised controlled trial of progesterone in preventing acute mountain sickness (AMS). The 11th International Hypoxia Symposium 1999. Hypoxia: Into the Next Millennium. Advances in Experimental Medicine and Biology. Eds. P. Hackett D. Wagner and R. Roach. 1999; 29: 388. Kluwer Academic Publishers.
  9. Hoar H, Imray C, Walsh S, Clarke T, Cooper M, Mole D, Wright A and BMRES. Carbon dioxide contributes to the beneficial effect of pressurization in a portable hyperbaric chamber. The 11th International Hypoxia Symposium 1999. Hypoxia: Into the Next Millennium. Advances in Experimental Medicine and Biology. Eds. P. Hackett D. Wagner and R. Roach. 1999; 29: 389-390. Kluwer Academic Publishers.
  10. Morgan J, Wright A, Hoar H, Hale D, Imray C and BMRES. Near-infrared cerebral spectroscopy to assess cerebral oxygenation at high altitude. The 11th International Hypoxia Symposium 1999. Hypoxia: Into the Next Millennium. Advances in Experimental Medicine and Biology. Eds. P. Hackett D. Wagner and R. Roach. 1999; 29: 413. Kluwer Academic Publishers. 
  11. Tiivas C, Williams D, Harvey T, Brearey S, Chesner I, Hoar H, Imray C and BMRES. Carbon dioxide and cerebral blood flow at sea level and on acute exposure to altitude. The 11th International Hypoxia Symposium 1999. Hypoxia: Into the Next Millennium. Advances in Experimental Medicine and Biology. Eds. P. Hackett D. Wagner and R. Roach. 1999; 29: 433-434. Kluwer Academic.
  12. Walsh S, Imray C, Clarke T, Mole D, Morgan J, Wright A and BMRES. Cerebral oxygenation at high altitude and the response to carbon dioxide, hyperventilation and oxygen. The 11th International Hypoxia Symposium 1999. Hypoxia: Into the Next Millennium. Advances in Experimental Medicine and Biology. Eds. P. Hackett D. Wagner and R. Roach. 1999; 29: 438-439. Kluwer Academic Publishers.
  13. Williams D, Tiivas C, Hale D, Walsh S, Clarke T, Imray C and BMRES. Reduction in cerebrovascular reserve capacity in normal individuals at altitude. The 11th International Hypoxia Symposium 1999. Hypoxia: Into the Next Millennium. Advances in Experimental Medicine and Biology. Eds. P. Hackett D. Wagner and R. Roach. 1999; 29: 440-441. Kluwer Academic Publishers. Publications: 2004
  14. Wright AD, Beazley MF, Bradwell AR, Chesner IM, Clayton RN, Forster PJG, Hillenbrand P and Imray CHE. Medroxyprogesterone at high altitude. The effects on blood gases, cerebral regional oxygenation and acute mountain sickness. Wilderness and Environmental Medicine 2004; 15: 25-31.
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