%0 Journal Article %T Relationship between Changes in Cerebral Blood Flow with Symptoms of Acute Mountain Sickness in Men Repeatedly Exposed to Simulated High Altitude %A Peter Ondru£¿ %A Roman Alberty %A Timothy Lyons %A Stephen Muza %A Vincent Echav¨¦ %A Jacques Poisson %A Allen Cymerman %J Advances in Physical Education %P 49-59 %@ 2164-0408 %D 2017 %I Scientific Research Publishing %R 10.4236/ape.2017.71005 %X
Objective: To study the relationship between changes in the cerebral blood flow (CBF) velocity with symptoms of acute mountain sickness (AMS) during simulated high altitude. Research Design and Methods: Mean middle arterial cerebral flow velocity (MCAv) was assessed by transcranial Doppler sonography in 8 healthy lowland male adults aged 20 - 24 yrs before and after 6 h and 48 h at simulated altitude corresponding to 4572 m. The same study was repeated three weeks later in the same subjects. End-tidal pCO2 (ETCO2) and arterial oxygen saturation (SaO2) were measured by standardized procedures. AMS symptoms were recorded using the modified environmental symptoms questionnaire after 6 h and 48 h exposure to calculate the mean score of cerebral (AMS-C) symptoms. Results: Mean MCAv significantly increased with high altitude (HA) by 4% at 6 h HA and 24% at 48 h HA (P < 0.05) compared to sea-level values. We observed a substantial inter-subject variance in MCAv changes, especially in the first hours upon altitude exposure. Within first 2 days, we found a moderate positive correlation between MCAv with decreased ETCO2 (mean ¡À SD 32 ¡À 4 mmHg; r = 0.47, P < 0.05), and a weak negative correlation of MCAv with a similar low SaO2 (77% ¡À 8%; r = - 0.43, P < 0.05). Five of the 10 original subjects developed symptoms of AMS; however, AMS-C scores decreased (P = 0.08) with increased duration of exposure (6 h HA 0.91 ¡À 1.09 vs 48 h HA 0.39 ¡À 0.40). No differences in AMS-C scores were observed when subjects with and without increased MCAv were compared at 6 h HA and 48 h HA. Furthermore, there was no correlation between changes in neither absolute nor relative MCAv and AMS-C scores. Severity of AMS symptoms coincided well with reduction in SaO2 (r = - 0.55, P < 0.05). Conclusion: Our results suggest that there is a lack of relationship between changes in CBF velocity with symptoms of AMS, and that a substantial inter-subject variance exists in the CBF response to high altitude exposure.
%K High-Altitude Sickness %K Cerebral Blood Flow %K Hypobaric Hypoxia %K Transcranial Doppler Sonography %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=74397