Work in Hypoxic Conditions-Consensus Statement of the Medical Commission of the Union Internationale des Associations d'Alpinisme (UIAA MedCom)

Objectives: The Commission gives recommendations on how to provide health and safety for employees in different kinds of low oxygen atmospheres. So far, no recommendations exist that take into account the several factors we have outlined in this report. Methods: The health and safety recommendations of several countries were analysed for their strength and deficiencies. The scientific literature was checked (Medline, etc.) and evaluated for relevance of the topic. Typical situations of work in hypoxia were defined and their specific risks described. Specific recommendations are provided for any of these situations. Results: We defined four main groups with some subgroups (main risk in brackets): short exposure (pressure change), limited exposure (acute altitude disease), expatriates (chronic altitude disease), and high-altitude populations (re-entry pulmonary oedema). For healthy unacclimatized persons, an acute but limited exposure down to 13% O2 does not cause a health risk. Employees should be advised to leave hypoxic areas for any break, if possible. Detailed advice is given for any other situation and pre-existing diseases. Conclusions: If the specific risk of the respective type of hypoxia is taken into account, a pragmatic approach to provide health and safety for employees is possible. In contrast to other occupational exposures, a repeated exposure as often as possible is of benefit as it causes partial acclimatization. The consensus statement was approved by written consent in lieu of a meeting in July 200

Chemoreceptor responsiveness at sea level does not predict the pulmonary pressure response to high altitude

The hypoxic ventilatory response (HVR) at sea level (SL) is moderately predictive of the change in pulmonary artery systolic pressure (PASP) to acute normobaric hypoxia. However, because of progressive changes in the chemoreflex control of breathing and acid-base balance at high altitude (HA), HVR at SL may not predict PASP at HA. We hypothesized that resting peripheral oxyhemoglobin saturation (SpO2) at HA would correlate better than HVR at SL to PASP at HA. In 20 participants at SL, we measured normobaric, isocapnic HVR (L/min·-%SpO2 -1) and resting PASP using echocardiography. Both resting SpO2 and PASP measures were repeated on day 2 (n=10), days 4-8 (n=12), and 2-3 weeks (n=8) after arrival at 5050m. These data were also collected at 5050m on life-long HA residents (Sherpa; n=21). Compared to SL, SpO2 decreased from 98.6 to 80.5% (P<0.001), while PASP increased from 21.7 to 34.0mmHg (P<0.001) after 2-3 weeks at 5050m. Isocapnic HVR at SL was not related to SpO2 or PASP at any time point at 5050m (all P>0.05). Sherpa had lower PASP (P<0.01) than lowlanders on days 4-8 despite similar SpO2. Upon correction for hematocrit, Sherpa PASP was not different from lowlanders at SL, but lower than lowlanders at all HA time points. At 5050m, whilst SpO2 was not related to PASP in lowlanders at any point (all R2=0.50), there was a weak relationship in the Sherpa (R2=0.16; P=0.07). We conclude that neither HVR at SL nor resting SpO2 at HA correlates with elevations in PASP at HA

Model Contract for Health Care on Trekking and Expeditions for Doctors – Recommendation of the Medical Commission of the Union Internationale des Associations d’Alpinisme (UIAA)

This suggested contract document attempts to clarify the rights and obligations of the tour operator (referred to herein as “organization”, OR), the ED and the EX to avoid trouble and misunderstandings during the trip. Being an Expedition or Trekking Doctor (referred to herein as “Expedition Doctor”, ED) is more than being merely a member which advises others in case of a health problem during the trip and who may get a discount on organized trips! An ED has specific responsibilities, has to provide special skills, and must always accept responsibility for any diagnosis made, whether right or wrong. Both, the tour operator and the participants of the Expedition (referred to herein as “Expedition”, EX) have their individual and often conflicting interests to which the ED’s own mountaineering interests must also be added. However, to minimize the possible multiple risks associated with these conflicts of interest, the rights, obligations and priorisation of medical and expedition scheduling should be made clear well in advance of the expedition. The following is a model text which may be adapted to an EX’s specific demands. In this text, EX includes the organizers of the trip, the expedition’s leaders and the participants

Przenośne komory hiperbaryczne w leczeniu chorób wysokościowych

Portable hyperbaric chambers are a therapeutic option for altitude disease in the mountains. By an increase of the oxygen partial pressure the patient’s symptoms ameliorate significantly. Portable hyperbaric chambers may be used as ‘stand alone therapy’ as well as in combination with other therapeutic options. Here we present the recommendation how to use the device and how to avoid problems. The recommendation has been agreed by all members of the medical commission of the world umbrella organization Union Internationale des Associations d’Alpinisme (UIAA MedCom)

The Borg Scale at high altitude

Introduction: The Borg Scale for perceived exertion is well established in science and sport to keep an appropriate level of workload or to rate physical strain. Although it is also often used at moderate and high altitude, it was never validated for hypoxic conditions. Since pulse rate and minute breathing volume at rest are increased at altitude it may be expected that the rating of the same workload is higher at altitude compared to sea level.Material and methods: 16 mountaineers were included in a prospective randomized design trial. Standardized workload (ergometry) and rating of the perceived exertion (RPE) were performed at sea level, at 3,000 m, and at 4,560 m. For validation of the scale Maloney-Rastogi-test and Bland-Altmann-Plots were used to compare the Borg ratings at each intensity level at the three altitudes; p < 0.05 was defined as significant.Results: In Bland-Altmann-Plots more than 95% of all Borg ratings were within the interval of 1.96 x standard deviation. There was no significant deviation of the ratings at moderate or high altitude. The correlation between RPE and workload or oxygen uptake was weak.Conclusion: The Borg Scale for perceived exertion gives valid results at moderate and high altitude – at least up to about 5,000 m. Therefore it may be used at altitude without any modification. The weak correlation of RPE and workload or oxygen uptake indicates that there should be other factors indicating strain to the body. What is really measured by Borg’s Scale should be investigated by a specific study