[Analysis of circulatory responses to orthostatic stress in the elderly]

An active orthostatic stress test was conducted on 32 elderly patients over 65 years (elderly group) and 17 normal adults, for a comparative evaluation of their blood pressure, heart rates, and plasma catecholamine responses. In addition, 8 patients in the elderly group underwent a study of orthostatic responses with or without sublingual administration of isosorbide dinitrate (ISDN). The results of the orthostatic responses were evaluated by Schellong's method. The elderly group produced a positive reaction in one (3.1%), and a weakly positive reaction in two (6.3%), while the remaining 29 (90.6%) and all of the normal adults showed negative responses. The systolic blood pressure pattern that developed in response to rising among the elderly group was significantly different (p less than 0.001) from that of the normal adult group, but the response pattern seen in the heart rates of the former approximated that of the latter. The plasma norepinephrine concentration 10 minutes after rising increased significantly (p less than 0.001) in both the elderly and normal adult groups. This increase amounted to 1.5-fold in the elderly group and 2-fold in normal subjects, with a less prominent increase shown by the elderly. The norepinephrine levels of the elderly group were significantly higher than those of the normal adults both before and 10 minutes after rising (p less than 0.001 and p less than 0.01, respectively). In the elderly, ISDN caused a significant drop in the systolic blood pressure immediately after rising and a significant increase in the heart rate. Sublingual ISDN administration resulted in a significant increase in the norepinephrine level (p less than 0.05) in association with rising. These findings indicated that the circulatory responses to orthostatic stimuli are inappropriate as clinical data among the elderly and the administration of ISDN exaggerates this shortcoming further.