[Informativeness of pulse bloodfilling of auricular helical vessels for evaluation of human tolerance to plusGz acceleration]. / Informativnost' pul'sovogo krovenapolneniia sosudov ushnoi rakoviny dlia otsenki ustoichivosti cheloveka k peregruzkam plusGz

The possiblity of using photoelectric plethysmography as an objective method to assess the human tolerance to accelerations was examined. The tolerance of 40 young healthy male test subjects to plus GZ accelerations of 3, 5, 6 and 7 g with an increase gradient of 0.4 g/sec and a plateau time of 30 sec was measured. The test subjects induced an arbitrary tension of the abdominal and leg muscles in order to better tolerate accelerations. When the tolerance reached its limit (as judging by optic disorders), the auricular pulse amplitude decreased 4-fold in 84% test subjects. The threshold value of the amplitude can be used as an informative indicator of a group and individual tolerance to plus GZ accelerations. A portable photoelectric plethysmograph has been designed for operational medical control of the health state of pilots inflight.