鋳鋼品製造工場における振動障害

第2報 皮膚知覚と末梢循環機能について

抄録

The purpose of the present study was to obtain better understanding of the sensory disturbances and the dysfunctions of blood flow of hands of 71 male workers who used the vibrating pneumatic tools (e.g., chipping hammer, air grinder and sand rammer) in a factory of steel foundry.
The vibrating tool users were asked to stay 30 minutes or over in a room at temperatures of 20° to 23°C and examined. The pain sense was tested on the dorsum of the middle phalanges by pinprick. The response to pinprick was determined with a intravenous injection needle 1/2mm in diameter pressed by various weights, and the threshold being expressed as grams. The vibratory sense was assessed at the ventral regions of the distal phalanges with a C-128 tuning fork, and the threshold being expressed as seconds, which showed the duration of the aroused sensation of vibration. The skin temperature was determined at the same part as that of the vibratory sense by a skin thermometer. The recovery time of blood flow was measured in seconds at the nail-bed of fingers by Yamada's “Nail Press Test.”
The workers were divided into three groups according to their duration of the work as vibrating tool users and the presence or absence of the attacks of Raynaud's phenomenon as follows : the first group consisted of 17 men who worked for less than 1/2 year ; the second group, 40 men who worked for 1/2 year or more and had no attack of Raynaud's phenomenon ; the third group, 14 men suffered from the attack of Raynaud's phenomenon.
The data were compared among the three groups. The results are as follows :
1. The prevalence of workers who showed the value of 3g or over as the threshold of pain sense was higher in the second and the third group than in the first group, and that of 5g or over, higer in the third group than in the second group.
2. The values of 8 seconds or less as the vibratory sense threshold were seen more in the third group than the other groups.
3. The workers who showed the skin temperature below 31.0°C were found more in the third group than in the other groups.
4. The third group had more workers who required 3 seconds or over for the recovery time of blood flow than the first group.
5. There were correlations between the increase in years of age and the degree of loss of pain sense in the third group, between the former and that of vibratory sense in the second and the third groups and between the length of the recovery time and the fall of the skin temperature in three groups.