Trapezius muscle metabolism measured with NIRS in helicopter pilots flying a simulator.
BACKGROUND
This study examined metabolic and hemodynamic responses during night vision goggle (NVG) induced neck strain among military helicopter pilots. We hypothesized that near infrared spectroscopy (NIRS) would be capable of identifying metabolic differences in the trapezius muscles of pilots between simulated flights with and without NVG.


METHODS
There were 33 pilots who were monitored on consecutive days during Day and NVG flight simulator missions. NIRS probes were attached bilaterally to the trapezius muscles at the C7 level to record total oxygenation index (TOI, %), total hemoglobin (tHb), oxyhemoglobin (HbO2), and deoxyhemoglobin (HHb).


RESULTS
Significant differences in tHb were found between Day (0.51+/-2.31 micromol x cm (-1)) and NVG (4.14 +/- 2.74 micromol x cm(-1)) missions, and for HbO2 (Dayend 2.63+/-1.64 micromol x cm(-1); NVGend 5.77+/-1.98 micromol x cm(-1)). Significant left and right side differences between Day and NVG were found for tHb (NVGleit -1.83+/-2.55; NVGright 10.45+/-2.86 micromol x cm(-1)), HbO2 (NVGleft 1.77+/-1.90; NVGright 9.95+/-2.07 micromol x cm(-1)), and HHb (Dayleft -1.84+/-0.95; Dayright -2.32+/-0.87 micromol x cm (-1); NVGleft -3.60+/-1.05 micromol x cm(-1); NVGright 0.49+/-1.16 micromol x cm(-1).


CONCLUSIONS
These results support NIRS's utility in assessing the significant metabolic and hemodynamic effects of NVG on neck musculature during real-time missions for 1) left and right side differences; and 2) Day vs. NVG missions. The additional mass of the NVG equipment does increase the metabolic stress of these muscles during simulated missions.
Harrison
Michael F
MF
University of Regina, Regina, SK, Canada.
Neary
J Patrick
JP
Albert
Wayne J
WJ
Veillette
Dan W
DW
McKenzie
Neil P
NP
Croll
James C
JC
D000328:Adult; D000337:Aerospace Medicine; D000401:Aircraft; D003198:Computer Simulation; D003624:Darkness; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008027:Light; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared; D014584:User-Computer Interface
D006454:Hemoglobins