In-flight cerebral oxygen status: continuous monitoring by near-infrared spectroscopy.
BACKGROUND
Little is known about the in-flight cerebral oxygen status (COS) of fighter pilots. The purpose of this study was to evaluate the COS of fighter pilots during an F-15DJ flight.


METHODS
Three male F-15DJ fighter pilots volunteered to serve as test subjects during aerial gunnery training (AGT) missions. During the flight, the pilots' COS was continuously monitored from the right forehead using a NIRO-300G near-infrared spectrophotometer. This new instrument is capable of measuring the concentration changes in the brain of oxygenated hemoglobin (O2Hb), reduced hemoglobin (HHb), total hemoglobin (cHb, O2Hb + HHb), and the tissue oxygenation index (TOI, O2Hb/cHb).


RESULTS
Continuous changes of COS within the brain were clearly demonstrated using NIRO-300G, the changes included reductions in O2Hb, cHb, and TOI with increased +Gz, in a mirror image fashion. The maximum decreased concentration of hemoglobin during flight ranged from 12.8 to 25.6 micromol x L(-1) (of brain tissue).


CONCLUSIONS
We believe this study is the first monitoring of COS during F-15 actual flight. The monitoring of COS during F-15 flight showed that the effect of +Gz was to simultaneously lower blood flow in a mirror image fashion. Our results demonstrated that near-infrared spectroscopy (NIRO-300G) provides a reliable and sensitive method for the monitoring of pilots' COS during flight.
Kobayashi
A
A
Aeromedical Laboratory, Japan Air Self Defense Force, Tachikawa-shi, Tokyo.
Miyamoto
Y
Y
D000054:Acceleration / Q000009:adverse effects; D000328:Adult; D000337:Aerospace Medicine / Q000379:methods*; D001923:Brain Chemistry; D002560:Cerebrovascular Circulation / Q000502:physiology; D006801:Humans; D018471:Hypergravity / Q000009:adverse effects; D002534:Hypoxia, Brain / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D007564:Japan; D008297:Male; D008889:Military Personnel; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D010101:Oxygen Consumption; D010108:Oxyhemoglobins / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
D010108:Oxyhemoglobins