We tested the hypotheses that 1) there is an age-associated decrease in arterial alpha-adrenergic responsiveness and 2) there is upregulation of this response during suppression of sympathetic nervous system (SNS) activity. We measured forearm blood flow (FABF) by plethysmography during brachial artery infusions of the alpha-adrenergic agonist norepinephrine (NE) and the nonadrenergic agonist angiotensin II (ANG II) in 15 young and 14 older healthy human subjects. Among the old (O) relative to the young (Y) we identified greater plasma NE levels (Y: 1.29 +/- 0.07 nM vs. O: 2.14 +/- 0.17 nM; P = 0.0001); a decrease in NE-mediated reduction in FABF [analysis of variance (ANOVA) P = 0.04]; and, in contrast, no difference in ANG II-mediated reduction in FABF (ANOVA P = 0.43). In the nine older subjects studied during guanadrel (G) to suppress SNS activity, we identified decreased plasma NE levels [placebo (P): 2.11 +/- 0.24 nM vs. G: 1.09 +/- 0.09 nM; P = 0.002], increased NE-mediated FABF response (ANOVA P = 0.01), and no difference in FABF response to ANG II (ANOVA: P = 0.69) compared with P. We conclude that there is appropriate desensitization of arterial alpha-adrenergic responsiveness among the older relative to the young subjects that is specific for the alpha-adrenergic system. Among the older subjects there is homologous upregulation of this response when SNS activity is suppressed.
In subjects with type 2 diabetes in whom an impaired response to an endothelial-dependent vasodilator has been characterized, the populations have also been at least moderately obese. Obesity has been characterized as an independent predictor of endothelial dysfunction in nondiabetic subjects. We hypothesized that in normotensive subjects with type 2 diabetes compared with age-matched control subjects, 1) endothelium-dependent vasodilation, as demonstrated by the forearm blood flow (FABF) response to intraarterial acetylcholine, would be decreased; 2) endothelium-independent vasodilation, as demonstrated by the FABF response to intraarterial nitroprusside, would be similar; 3) the degree of insulin resistance, as measured by the insulin sensitivity index (SI), would predict greater impairment in the FABF response to acetylcholine; and 4) these relationships would be independent of obesity. We measured FABF by venous occlusion plethysmography during brachial arterial infusions of the endothelium-dependent vasodilator acetylcholine and the endothelium-independent vasodilator nitroprusside in 20 control and 17 subjects with type 2 diabetes. We measured SI using the frequently sampled i.v. glucose tolerance test. Among the diabetic relative to the control subjects we identified a decrease in the acetylcholine-mediated percent increase in FABF (P = 0.02). Using the absolute FABF response to acetylcholine and including adjustments for body mass index and other covariates, the overall group difference remained and was noted to be greatest in those subjects who had lower baseline FABFs. In contrast, no significant difference in the nitroprusside-mediated increase in the percent change FABF was identified between groups (P = 0.30). Finally, the degree of insulin resistance, as measured by SI, did not independently predict greater impairment of the FABF response to acetylcholine. This study is the first to identify specific endothelial cell dysfunction that remains significant after adjustment for obesity in a population of normotensive subjects with type 2 diabetes.
OBJECTIVE:To assess the effects of a multimedia educational intervention about advance directives (ADs) and cardiopulmonary resuscitation (CPR) on the knowledge, attitude and activity toward ADs and life-sustaining treatments of elderly veterans. DESIGN:Prospective randomized controlled, single blind study of educational interventions. SETTING:General medicine clinic of a university-affiliated Veterans Affairs Medical Center (VAMC). PARTICIPANTS:One hundred seventeen Veterans, 70 years of age or older, deemed able to make medical care decisions. INTERVENTION:The control group ( n ؍ 55) received a handout about ADs in use at the VAMC. The experimental group ( n ؍ 62) received the same handout, with an additional handout describing procedural aspects and outcomes of CPR, and they watched a videotape about ADs. MEASUREMENTS AND MAIN RESULTS:Patients' attitudes and actions toward ADs, CPR and life-sustaining treatments were recorded before the intervention, after it, and 2 to 4 weeks after the intervention through self-administered questionnaires. Only 27.8% of subjects stated that they knew what an AD is in the preintervention questionnaire. This proportion improved in both the experimental and control (87.2% experimental, 52.5% control) subject groups, but stated knowledge of what an AD is was higher in the experimental group (odds ratio ؍ 6.18, p Ͻ .001) and this effect, although diminished, persisted in the follow-up questionnaire (OR ؍ 3.92, p ؍ .003). Prior to any intervention, 15% of subjects correctly estimated the likelihood of survival after CPR. This improved after the intervention in the experimental group (OR ؍ 4.27, p ؍ .004), but did not persist at follow-up. In the postintervention questionnaire, few subjects in either group stated that they discussed CPR or ADs with their physician on that day (OR ؍ 0.97, p ؍ NS). CONCLUSION:We developed a convenient means of educating elderly male patients regarding CPR and advance directives that improved short-term knowledge but did not stimulate advance care planning.
BackgroundThe program “Implementing Goals of Care Conversations with Veterans in VA LTC Settings” is proposed in partnership with the US Veterans Health Administration (VA) National Center for Ethics in Health Care and the Geriatrics and Extended Care Program Offices, together with the VA Office of Nursing Services. The three projects in this program are designed to support a new system-wide mandate requiring providers to conduct and systematically record conversations with veterans about their preferences for care, particularly life-sustaining treatments. These treatments include cardiac resuscitation, mechanical ventilation, and other forms of life support. However, veteran preferences for care go beyond whether or not they receive life-sustaining treatments to include issues such as whether or not they want to be hospitalized if they are acutely ill, and what kinds of comfort care they would like to receive.MethodsThree projects, all focused on improving the provision of veteran-centered care, are proposed. The projects will be conducted in Community Living Centers (VA-owned nursing homes) and VA Home-Based Primary Care programs in five regional networks in the Veterans Health Administration. In all the projects, we will use data from context and barrier and facilitator assessments to design feedback reports for staff to help them understand how well they are meeting the requirement to have conversations with veterans about their preferences and to document them appropriately. We will also use learning collaboratives—meetings in which staff teams come together and problem-solve issues they encounter in how to get veterans’ preferences expressed and documented, and acted on—to support action planning to improve performance.DiscussionWe will use data over time to track implementation success, measured as the proportions of veterans in Community Living Centers (CLCs) and Home-Based Primary Care (HBPC) who have a documented goals of care conversation soon after admission. We will work with our operational partners to spread approaches that work throughout the Veterans Health Administration.Electronic supplementary materialThe online version of this article (doi:10.1186/s13012-016-0497-0) contains supplementary material, which is available to authorized users.
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