We have observed that there is a large subset of geriatric patients who develop relative hypotension during physiologic stress and, when treated with vasopressors, are difficult to wean from them. This phenomenon has been especially noted in malnourished individuals. The vasomotor component of peripheral resistance mediated by the sympathetic nervous system deteriorates with age and metabolic derangements, particularly diabetes mellitus. Since malnutrition has substantial effects on peripheral nervous system function, we evaluated the effect of nutritional status on sympathetic vasomotor competence utilizing the cold pressor response (CPR).
Study Design: Prospective data collection. A complete nervous system evaluation was performed, with special attention to mental status and peripheral sensation of pain and cold in order to assure the integrity of the sensory limb of the CPR. Blood pressure was measured in both arms, and the cuff placed on the arm with the higher pressure. The contralateral hand was then immersed in ice water for 70 seconds, and the blood pressure determination repeated. Clinical and laboratory data were collected from the clinical record. The magnitudes of the systolic, diastolic and mean arterial pressure responses to cold challenge were correlated graphically with albumin level(ALB), total lymphocyte count(TLC), body mass index(BMI), age and other clinical data.
22 nondiabetic patients were evaluated (13 women, 9 men; age 73±7yr). None were on vasopressors. All had normal mental status and peripheral nervous system function. All CPRs were lower than normal (diastolic response 3.5±6mm Hg, systolic 0.8±13 mm Hg) but within the group there was no correlation between CPR and either age or use of vasodilating medications. There was an inverse relationship between BMI and CPR (CPR=-0.7BMI) and a direct relationship between CPR and ALBxTLC (CPR=0.75xALBxTLC). There were weaker relationships between CPR and individual variables.
Sympathetic competence is impaired in older adults and is further adversely affected by malnutrition and obesity.
The sick elderly should be evaluated for nutritional deficiency and for vasomotor incompetence to stratify their risk for hemodynamic destabilization.
W.D. Marino, None.