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Intubation dans le noir: Plutôt Poncho que JVN

A Study on the Tactical Safety of Endotracheal Intubation Under Darkness.


Strict blackout discipline is extremely important for all military units. To be able to effectively determine wound characteristics and perform the necessary interventions at nighttime, vision and light restrictions can be mitigated through the use of tactical night vision goggles (NVGs). The lamp of the classical laryngoscope (CL) can be seen with the naked eye; infrared light, on the other hand, cannot be perceived without the use of NVGs. The aim of the study is to evaluate the safety of endotracheal intubation (ETI) procedures in the darkunder tactically safe conditions with modified laryngoscope (ML) model.


We developed an ML model by changing the standard lamp on a CL with an infrared light-emitting diode lamp to obtain a tool which can be used to perform ETI under night conditions in combination with NVGs. We first evaluated the safety of ETI procedures in prehospital conditions under darkness by using both the CL and the ML for the study, and then researched the procedures and methods by which ETI procedure could be performed in the dark under tactically safe conditions. In addition, to better ensure light discipline in the field of combat, we also researched the benefits, from a light discipline standpoint, of using the poncho liner (PL) and of taking advantage of the oropharyngeal region during ETIs performed by opening the laryngoscope blades directly in the mouth and using a cover. During the ETI procedures performed on the field, two experienced combatant staff simulated the enemy by determining whether the light from the two different types of laryngoscope could be seen at 100-m intervals up to 1,500 m.


In all scenarios, performing observations with an NVG was more advantageous for the enemy than with the naked eye. The best measure that can be taken against this threat by the paramedic is to ensure tactical safety by having an ML and by opening the ML inside the mouth with the aid of a PL. The findings of the study are likely to shed light on the tactical safety of ETI performed with NVGs under darkness.


Considering this finding, we still strongly recommend that it would be relatively safer to open the ML blade inside the mouth and to perform the procedures under a PL. In chaotic environments where it might become necessary to provide civilian health services for humanitarian aid purposes (Red Crescent, Red Cross, etc.) without NVGs, we believe that it would be relatively safer to open the CL blade inside the mouth and to perform the procedures under a PL.

Pour voir: Etre dans le bleu!

 Safest light in a combat area while performing intravenous access in the dark.


Cannulation for the administration of intravenous fluids is integral to the prehospital management of injured military patients. However, this may be technically challenging to undertake during night-time conditions where the use of light to aid cannulation may give the tactical situation away to opponents. The aim of this study was to investigate the success and tactical safety of venepuncture under battlefield conditions with different colour light sources.


The procedure was carried out with naked eye in a bright room in the absence of a separate light source, with a naked eye in a dark room under red, white, blue and green light sources and under an infrared light source while wearing night vision goggles (NVGs). The success, safety, degree of difficulty and completion time for each procedure were then explored.


All interventions made in daylight and in a dark room were found to be 100% successful. Interventions performed under infrared light while wearing NVGs took longer than under other light sources or in daylight. Interventions performed under blue light were tactically safer when compared with interventions performed under different light sources.


Blue light offered the best tactical safety during intravenous cannulation under night-time conditions and is recommended for future use in tactical casualty care. The use of NVGs using infrared light cannot be recommended if there is the possibility of opponents having access to the technology.


Intervenir sur une tuerie massive: Un savoir faire à acquérir

3 Echo: concept of operations for early care and evacuation of victims of mass violence.

This report describes the successful use of a simple 3-phase approach that guides the initial 30 minutes of a response to blast and active shooter events with casualties: Enter, Evaluate, and Evacuate (3 Echo) in a mass-shooting event occurring in Minneapolis, Minnesota USA, on September 27, 2012. Early coordination between law enforcement (LE) and rescue was emphasized, including establishment of unified command, a common operating picture, determination of evacuation corridors, swift victim evaluation, basic treatment, and rapid evacuation utilizing an approach developed collaboratively over the four years prior to the event. Field implementation of 3 Echo requires multi-disciplinary (Emergency Medical Services (EMS), fire and LE) training to optimize performance.

3Echo Concept.png

This report details the mass-shooting event, the framework created to support the response, and also describes important aspects of the concepts of operation and curriculum evolved through years of collaboration between multiple disciplines to arrive at unprecedented EMS transport times in response to the event.


Combat en montagne: Soutien médical

Challenges of Military Health Service Support in Mountain Warfare

Raimund Lechner et Al.


Un environnement hostile pour des blessés particuliers et des équipes médicales dont l'entraînement doit être au plus haut. Lire aussi



History is full of examples of the influence of the mountain environment on warfare. The aim of this article is to identify the main environmental hazards and summarize countermeasures to mitigate the impact of this unique environment.


A selective PubMed and Internet search was conducted. Additionally, we searched bibliographies for useful supplemental literature and included the recommendations of the leading mountain medicine and wilderness medicine societies.


A definition of mountain warfare mainly derived from environmental influences on body functions is introduced to help identify the main environmental hazards. Cold, rugged terrain, hypoxic exposure, and often a combination and mutual aggravation of these factors are the most important environmental factors of mountain environment. Underestimating this environmental influence has decreased combat strength and caused thousands of casualties during past conflicts. Some marked differences between military and civilian mountaineering further complicate mission planning and operational sustainability.


To overcome the restrictions of mountain environments, proper planning and preparation, including sustained mountain mobility training, in-depth mountain medicine training with a special emphasize on prolonged field care, knowledge of acclimatization strategies, adapted time calculations, mountain-specific equipment, air rescue strategies and makeshift evacuation strategies, and thorough personnel selection, are vital to guarantee the best possible medical support. The specifics of managing risks in mountain environments are also critical for civilian rescue missions and humanitarian aid.


Guide de médecine rurale AUS


Clic sur l'image pour accéder au document


Retex du soutien d'une opération aéroportée

Delayed drop zone evacuationexecution of the medical plan for an airborne operation into northern Iraq.


Un publication déjà ancienne, mais l'expérience rapportée est assez unique et porte sur l'emploi d'une antenne chirurgicale et des conditions d'emploi lors des premières heures.


Flying directly from its home station in Vicenza, Italy, the 173rd Airborne Brigade committed itself to the invasion of Iraq on the night of March 26, 2003. Representing the establishment of a northern front, approximately 1,000 paratroopers jumped into an isolated valley on a mission to secure and to hold the Bashur airstrip. This article describes the unique challenges of medical preparation for the mission, injuries sustained on the jump, and lessons learned. Emphasis is placed on the use of a policy of delayed evacuation until clarification of diagnosis.

Lunettes de vision nocturne: Une aide ? A voir !

A new perspective on life-saving procedures in a battlefield setting: Emergency cricothyroidotomy, needle thoracostomy, and chest tube thoracostomy with night vision goggles.


Des résultats bien étonnants quand on connait les problèmes de profondeur de champ inhérents à l'emploi de dispositifs de vision nocturne, surtout monoculaires. Comme toujours maîtriser le geste en conditions normales, maîtriser l'outil de vision et s'entraîner dans ces conditions. Lire également 1, 2, 3




In the patients with multiple and serious trauma, early applications of life-saving procedures are related to improved survival. We tried to experimentally determine the feasibility of life-saving interventions that are performed with the aid of night vision goggles (NVG) in nighttime combat scenario.


Chest tube thoracostomy (CTT), emergency cricothyroidotomy (EC), and needle thoracostomy (NT) interventions were performed by 10 combatant medical staff. The success and duration of interventions were explored in the study. Procedures were performed on the formerly prepared manikins/models in a bright room and in a dark room with the aid of NVG. Operators graded the ease of interventions.


All interventions were found successful. Operators stated that both CTT and EC interventions were more difficult in dark than in daytime (p<0.05). No significant difference was observed in the difficulty in the NT interventions. No significant difference was observed in terms of completion times of interventions between in daytime and in dark scenario.


The operators who use NVGs have to be aware of that they can perform their tactic and medical activities without taking off the NVGs and without the requirement of an extra light source.

| Tags : vision nocturne


Gelures graves: Plus tôt la thrombolyse

Time Matters in Severe Frostbite: Assessment of Limb/Digit Salvage on the Individual Patient Level.
Un article très intéressant car il utilise d'une part le score d'hennepin et d'autre part a recours à une imagerie TDM très précoce pour documenter des déficits de vascularisation après réchauffement et dès lors indiquer la thrombolyse.

Severe frostbite is associated with high levels of morbidity through loss of digits or limbs. The aim of this study was to examine the salvage rate following severe frostbite injury. Frostbite patients from 2006 to 2014 were identified in the prospectively maintained database at a single urban burn and trauma center. Patients with imaging demonstrating a lack of blood flow in limbs/digits were included in the analysis (N = 73). The Hennepin Frostbite Score was used to quantify frostbite injury and salvage. This score provides a single value to assess each individual patient's salvage rate. The majority of patients with perfusion deficits were male (80%) with an average age of 42 years (range 11-83 years). Patients requiring amputation tended to be older (P = .002), have more tissue impacted by frostbite (P < .001), and experienced a longer time from rewarming to thrombolytic therapy (P = .001). A majority of patients (62%) received thrombolytic treatment. The percentage of patients requiring amputation was lower and the salvage rate was higher in patients treated with thrombolytics; however, the differences failed to reach statistical significance (P = .092 and P = .061, respectively). The rate of salvage decreases as the time from rewarming to thrombolytic therapy increases. Regression analysis demonstrates an additional 26.8% salvage loss with each hour of delayed treatment (P = .006). When the amount of tissue at risk for amputation is included in the model, each hour delay in thrombolytic treatment results in a 28.1% decrease in salvage (P = .011). This study demonstrates a significant decrease in limb/digit salvage with each hour of delayed administration of thrombolytics in patients with severe frostbite

| Tags : gelures


MEDEVAC de la BSS: En gros que fait on ?

Forward medevac during Serval and Barkhane operations in Sahel: A registry study.

Carfantan C, et Al. Injury. 2017 Jan;48(1):58-63.


Une activité particulièrement sensible dont la lecture permet de comprendre toute la complexité de la prise en charge de nos soldats dans un contexte d'élongation majeure. On comprend également tous les enjeux de positionnement d'équipes sanitaires ayant la maîtrise de certaines pratiques avancées de réanimation préhospitalière.




The French army has been deployed in Mali since January 2013 with the Serval Operation and since July 2014 in the Sahel-Saharan Strip (SSS) with the Barkhane Operation where the distances (up to 1100km) can be very long. French Military Medical Service deploys an inclusive chain from the point of injury (POI) to hospital in France. A patient evacuation coordination cell (PECC) has been deployed since February 2013 to organise forward medical evacuation (MEDEVAC) in the area between the POI and three forward surgical units. The purpose of this work was to study the medical evacuation length and duration between the call for Medevac location accidents and forward surgical units (role 2) throughout the five million square kilometers French joint operation area.


Our retrospective study concerns the French patients evacuated by MEDEVAC from February 2013 to July 2016. The PECC register was analysed for patients' characteristics, NATO categorisation of gravity (Alpha, Bravo or Charlie who must be respectively at hospital facility within 90min, 4h or 24h), medical motive for MEDEVAC and the time line of each MEDEVAC (from operational commander request to entrance in role 2).


A total of 1273 French military were evacuated from February to 2013 to July 2016; 533 forward MEDEVAC were analysed. 12,4% were Alpha, 28,1% Bravo, 59,5% Charlie. War-related injury represented 18,2% of MEDEVAC. The median time for Alpha category MEDEVAC patients was 145min [100-251], for Bravo category patients 205min [125-273] and 310min [156-669] for Charlie. The median distance from the point of injury to role 2 was 126km [90-285] for Alpha patients, 290km [120-455] km for Bravo and 290km [105-455] for Charlie.


Patient evacuation in such a large area is a logistic and human challenge. Despite this, Bravo and Charlie patients were evacuated in NATO recommended time frame. However, due to distance, Alpha patients time frame was longer than this recommended by NATO organisation. That's where French doctrine with forward medical teams embedded in the platoons is relevant to mitigate this distance and time frame challenge.

| Tags : evasan


Hypothermie accidentelle: Vision scandinave

Accidental hypothermia-an update : The content of this review is endorsed by the International Commission for Mountain Emergency Medicine (ICAR MEDCOM).

Paal et al. Scand J Trauma Resusc Emerg Med. (2016) 24:111



This paper provides an up-to-date review of the management and outcome of accidental hypothermia patients with and without cardiac arrest.


The authors reviewed the relevant literature in their specialist field. Summaries were merged, discussed and approved to produce this narrative review.


The hospital use of minimally-invasive rewarming for non-arrested, otherwise healthy, patients with primary hypothermia and stable vital signs has the potential to substantially decrease morbidity and mortality for these patients. Extracorporeal life support (ECLS) has revolutionised the management of hypothermic cardiac arrest, with survival rates approaching 100 % in some cases. Hypothermic patients with risk factors for imminent cardiac arrest (temperature <28 °C, ventricular arrhythmia, systolic blood pressure <90 mmHg), and those who have already arrested, should be transferred directly to an ECLS-centre. Cardiac arrest patients should receive continuous cardiopulmonary resuscitation (CPR) during transfer. If prolonged transport is required or terrain is difficult, mechanical CPR can be helpful. Delayed or intermittent CPR may be appropriate in hypothermic arrest when continuous CPR is impossible. Modern post-resuscitation care should be implemented following hypothermic arrest. Structured protocols should be in place to optimise pre-hospital triage, transport and treatment as well as in-hospital management, including detailed criteria and protocols for the use of ECLS and post-resuscitation care.


Based on new evidence, additional clinical experience and clearer management guidelines and documentation, the treatment ofaccidental hypothermia has been refined. ECLS has substantially improved survival and is the treatment of choice in the patient with unstable circulation or cardiac arrest.


| Tags : hypothermie


Chaud et froid: Nous aussi !

Critical care at extremes of temperature: effects on patients, staff and equipment

Hindle EM, et al. J R Army Med Corps 2014;160:279–285


Le chaud et le froid ont aussi des effets sur notre performance, et il faut en tenir compte.


Modern travel and military operations have led to a significant increase in the need to provide medical care in extreme climates. Presently, there are few data on what happens to the doctor, their drugs and equipment when exposed to these extremes. A review was undertaken to find out the effects of ‘extreme heat or cold’ on anaesthesia and critical care; in addition, subject matter experts were contacted directly. Both extreme heat and extreme cold can cause a marked physiological response in a critically ill patient and the doctor treating these patients may also suffer a decrement in both physical and mental functioning. Equipment can malfunction when exposed to extremes of temperature and should ideally be stored and operated in a climatically controlled environment. Many drugs have a narrow range of temperatures in which they remain useable though some have been shown to remain effective if exposed to extremes of temperature for a short period of time. All personnel embarking on an expedition to an extreme temperature zone should be of sufficient physical robustness and ideally should have a period of acclimatisation which may help mitigate against some of the physiological effects of exposure to extreme heat or extreme cold. Expedition planners should aim to provide climatic control for drugs and equipment and should have logistical plans for replenishment of drugs and medical evacuation of casualties.


Coup de chaleur: Position US





Le coup de chaleur d'exercice est une réalité. Un refroidissement obtenu en moins de 30 minutes est indispensable. L'immersion corps entier est la méthode la plus efficace mais n'est pas forcément disponible. Le refroidissement par immersion des membres supérieurs est discuté. Une approche très intéressante semble être l'emploi de nouvelles couvertures refroidissantes (lien) qui permettent un abaissement significatif des mesures de refroississement dès le lieu de prise en charge et pendant toute la phase de transport.

| Tags : hyperthermie


Hypoxie d'altitude: Pour les AMET AUSSI !

Effects of Altitude-Related Hypoxia on Aircrews in Aircraft With Unpressurized Cabins

Nishi S. Military Medicine, 176, 1:79, 2011


La prise en charge de blessés en altitude ajoute à l'hémorragie le problème de l'hypoxie liée à la baisse de la PAO2 par baisse de la pression barométrique. Ceci joue aussi pour les sauveteurs, dès 1500 m,  dont la performance peut être moindre avec une réduction de la capcité de concentration et une baisse d'acuité visuelle marquée à partir de 3000 m. Cela peut être le cas des équipes AMET dès lors que les cabines ne sont pas pressurisées


Introduction: Generally, hypoxia at less than 10,000 ft (3,048 m) has no apparent effect on aircrews. Nevertheless, several hypoxic incidents have been reported in flights below 10,000 ft. A recently introduced pulse oximeter using finger probes allows accurate monitoring of oxygen saturation (SPO 2 ) in the aeromedical environment. Using such a pulse oximeter, inflight SPO 2 levels were evaluated in aircrew in unpressurized aircraft. In addition, career in- flight hypoxic experiences were surveyed.

Methods: In-fl ight SPO 2 was measured in aircrews operating UH-60J helicopters at up to 13,000 ft, and 338 aircrew members operating unpressurized cabin aircraft were surveyed concerning possible in-fl ight hypoxic experiences.

Results: In aircrews operating UH-60J helicopters, SPO 2 decreased significantly at altitudes over 5,000 ft, most markedly at 13,000 ft (vs. ground level). The survey identified three aircrew members with experiences suggesting hypoxemia at below 5,000 ft.

Conclusions: Careful attention should be paid to the possibility of hypoxia in aircrews operating unpressurized cabin aircraft. 

| Tags : altitude


Gestion des contraintes thermiques

Management of Heat and Cold Stress – Guidance to NATO Medical Personnel

Findings of Task Group HFM-187



Egalement:  Consensus recommendations on training and competing in the heat


Hyperthermie d'effort: Quoi de neuf ?

Exertional Heat Stroke: New Concepts Regarding Cause and Care

Casa DJ  et All. Curr Sports Med Rep. 2012 May-Jun;11(3):115-23


Une bibliographie très riche pour ce qui est pour nous une préoccupation régulière. Lire aussi (1, 2,3)


When athletes, warfighters, and laborers perform intense exercise in the heat, the risk of exertional heat stroke (EHS) is ever present. The recent data regarding the fatalities due to EHS within the confines of organized American sport are not promising: during the past 35 years, the highest number of deaths in a 5-year period occurred from 2005 to 2009. This reminds us that, regardless of the advancements of knowledge in the area of EHS prevention, recognition, and treatment, knowledge has not been translated into practice. This article addresses important issues related to EHS cause and care. We focus on the predisposing factors, errors in care, physiology of cold water immersion, and return-to-play or duty considerations

| Tags : hyperthermie


Froid: Alaska Guide 2014

ColdInjuriesAlaska Guidelines.jpg

Clic sur l'image pour accéder au document

| Tags : hypothermie


Médecine d'altitude: Manuel sponsorisé par l'OTAN


Clic sur l'image pour accéder au document

| Tags : altitude


OHB des gelures: Etudes des pratiques européennes ?

Place de l'oxygenotherapie hyperbare dans le traitement des gelures : Evaluations des pratiques europeennes

Thèse de médecine Kolakowska E.

À l’heure actuelle, l’oxygénothérapie hyperbare (OHB) ne fait pas partie des recommandations pour le traitement des gelures et pourtant elle est proposée par plusieurs spécialistes. La gelure est une lésion tissulaire survenant lors d’une exposition prolongée et directe à une température inférieure à 0 °C. L’OHB pourrait être utile par le biais de l’amélioration de l’oxygénation locale, la limitation de l’oedème, la lutte contre l’infection et la stimulation des processus de cicatrisation. L’équipe du centre hyperbare de l’Hôpital de Sainte-Marguerite à Marseille avait traité les victimes de gelures avec des résultats très encourageants, ce qui nous a motivé à évaluer les pratiques concernant l’utilisation de l’OHB dans la prise en charge des gelures dans différents centres hyperbares Européens et vérifier, s’il avait existé un bénéfice thérapeutique. Il s’agit d’une étude réalisée à l’aide d’un questionnaire auprès des médecins exerçant aux caissons hyperbares en Europe. Sur 134 messages envoyés, 21 médecins avaient rempli le questionnaire. 86 % des spécialistes estimaient que théoriquement l’OHB pourrait être indiquée dans la prise en charge de gelures. Parmi les 25 patients inclus, 84 % avaient été atteints de gelures profondes et seulement 44% avaient bénéficié d’une prise en charge dans les premières 72 heures. Malgré la gravité des lésions et le délai de la prise en charge, nous avons constaté, qu’à 3 mois d’évolution, 88 % des patients avaient présenté une amélioration sur le plan cutané par rapport à l’état initial. Bien que notre étude ne soit pas d’une grande valeur statistique, elle permet toutefois de s’apercevoir du bénéfice thérapeutique que l’OHB pourrait apporter dans cette pathologie, y compris tardivement. En effet, des études prospectives larges seront nécessaires et justifiées.

Rappel: Schéma physiopathologique de la gelure 

Gelure Physiopath.jpg

| Tags : gelures


Médecine de haute altitude: En pratique, c'est quoi ?

Mount Everest Base Camp Medical Clinic “Everest ER”: Epidemiology of Medical Events During the First 10 Years of Operation

Pressman BA et AL. Wilderness Environ Med. 2015 Mar;26(1):4-10


Si l'intervention dans de telles conditions nécessite évidemment une pratique réelle de la montagne en haute altitude, la spécificité de la pathologie médicale rencontrée semble être essentiellement en rapport avec l'isolement.



As the highest peak on the planet, Mount Everest provides a truly austere environment in which to practice medicine. We examined records of all visits to the Everest Base Camp Medical Clinic (Everest ER) to characterize the medical problems that occur in these patients.


A retrospective analysis of medical records from the first 10 years of operation (2003–2012) was performed. Descriptive data collected included patient demographics, diagnoses, treatments, prescriptions, medications dispensed, and evacuation type, if any.

Results: In all, 2941 patients were seen for a total of 3569 diagnoses. The number of patient visits each year at the Everest ER increased at a greater rate than the total numbers of climbers attempting Mount Everest over this period. The most commonly treated patients were Nepalese, accounting for 51% of all nationalities. The most common medical diagnoses were from pulmonary causes such as high altitude cough and upper respiratory infections, comprising more than 38% of all medical diagnoses. The most common traumatic diagnoses were from dermatologic causes such as frostbite and lacerations, comprising 56% of all traumatic diagnoses. Pulmonary and dermatologic diagnoses were also the most frequent reasons for evacuation from Everest Base Camp, most commonly for high altitude pulmonary edema and frostbite, respectively.


Medical professionals treating patients at extreme altitude should have a broad scope of practice and should be well prepared to deal with serious traumas from falls, cold exposure injuries, and altitude illness.

| Tags : altitude


O2 pas mieux extrait lors de l'effort en altitude !

Systemic oxygen extraction during exercise at high altitude

Martin DS et Al. British Journal of Anaesthesia 114 (4): 677–82 (2015)


On pourrait penser que qu'un des mécanismes d'adaptation à l'effort conduit en haute altitude soit l'augmentation de l'extraction d'oxygène, il semble qu'il n'en soit rien. C'est ce que suggère le travail proposé qui avance par ailleurs que ceci serait en relation avec:

1. Une anomalie de diffusion tissulaire de l'oxygène notamment à cause de la baisse du gradient de pression partielle entre capillaire et mitochondrie, ceci étant associé à la réduction du temps de transit capillaire musculaire  en rapport avec l 'effort.

2. Des anomalies régionales de besoins en oxygène avec hétérogénéité des débits sanguins régionaux.

3. La redistribution des débits sanguins musculaires vers les organes dits "nobles"

4. La réduction de la consommation au niveau mitochondrial

En altitude la consommation en oxygène est plus en rapport avec la consommation mitochondriale qu'avec la délivrance d'oxygène aux tissus. 

Ces observations vont l 'opposé de ce que l'on peut observer en cas d'hémorragie. On peut se poser la question des mécanismes d'adaptations en cas d'hémorragie survenant dans les mêmes conditions. EN tous cas ne changeons rien, continuons d'en apporter.



Classic teaching suggests that diminished availability of oxygen leads to increased tissue oxygen extraction yet evidence to support this notion in the context of hypoxaemia, as opposed to anaemia or cardiac failure, is limited.


At 75 m above sea level, and after 7–8 days of acclimatization to 4559 m, systemic oxygen extraction [C(a2v)O2] was calculated in five participants at rest and at peak exercise. Absolute [C(a2v)O2] was calculated by subtracting central venous oxygen content (CcvO2) from arterial oxygen content (CaO2 ) in blood sampled from central venous and peripheral arterial catheters, respectively. Oxygen uptake (VO˙ 2) was determined from expired gas analysis during exercise.


Ascent to altitude resulted in significant hypoxaemia; median (range) SpO2 87.1 (82.5–90.7)% and PaO2 6.6 (5.7–6.8) kPa. While absolute C(a-v)O2 was reduced at maximum exercise at 4559 m [83.9 (67.5–120.9) ml litre-1 vs 99.6 (88.0–151.3) ml litre-1 at 75 m, P¼0.043], there was no change in oxygen extraction ratio (OER) [C(a-v)O2/CaO2] between the two altitudes [0.52 (0.48–0.71) at 4559 m and 0.53 (0.49–0.73) at 75 m, P¼0.500]. Comparison of C(a-v)O2 at peak VO˙ 2 at 4559 m and the equivalent VO˙ 2 at sea level for each participant also revealed no significant difference [83.9 (67.5–120.9) ml litre1 vs 81.2 (73.0–120.7) ml litre-1 , respectively, P¼0.225].


In acclimatized individuals at 4559 m, there was a decline in maximum absolute C(a-v)O2 during exercise but no alteration in OER calculated using central venous oxygen measurements. This suggests that oxygen extraction may have become limited after exposure to 7–8 days of hypoxaemia.