Measurements of right-ventricular (RV) ejection fraction on ultrasound can be used to reliably predict who will get acute mountain sickness, Italian and French researchers reported on 12 December at EuroEcho-Imaging 2013 in Istanbul.
Hypothesizing that cardiovascular maladaptation to hypoxia is responsible for acute mountain sickness syndromes and that early identification could predict future development of symptoms, a team lead by Dr. Rosa Maria Bruno from the department of internal medicine at University of Pisa in Italy, evaluated cardiovascular function using ultrasound-based techniques in 34 healthy volunteers at sea level and after passive ascent by cable car to 3,842 meters at Aiguille du Midi, France.
About one-third of the individuals had previously experienced an episode of high-altitude cerebral and/or pulmonary edema. After 24 hours at 3,842 meters, 13 of the 34 volunteers developed symptoms of moderate to severe acute mountain sickness.
While their cardiovascular function at sea level was similar to the remaining group, these 13 had significant alterations in cardiovascular adaptation to hypoxia after only four hours from arrival at high altitude, according to the researchers. Their oxygen saturation was significantly lower and the systolic function of the RV, as evaluated by the tricuspid annular plane systolic excursion (TAPSE) echocardiographic measure of RV ejection fraction, decreased despite a similar increase in pulmonary artery pressure compared with subjects without acute mountain sickness symptoms.
TAPSE was unchanged in individuals without acute mountain sickness symptoms.
The combination of oxygen saturation less than 87% and a TAPSE value less than 28 mm after four hours of exposure to high altitude could predict who will develop acute mountain sickness the day after with 94% negative predictive value and 92% sensitivity, according to the authors.
If these results are confirmed by larger studies, it will be possible to identify vulnerable individuals and suggest particular behaviors and drugs only to this subgroup, Bruno said in a statement.
