Improved baroreflex sensitivity in elderly hypertensives on lisinopril is not explained by blood pressure reduction alone.

OBJECTIVE: The major goals of this study were to determine whether lisinopril and nifedipine lowered blood pressure and improved carotid baroreflexes in older hypertensives. DESIGN: The effects of lisinopril at 10-40 mg/day versus nifedipine gastrointestinal therapeutic system (GITS) at 30-90 mg/day on blood pressure and baroreflex sensitivity were studied after 3 weeks each on (1) single-blind placebo, (2) double-blind assignment to either lisinopril or nifedipine, (3) single-blind placebo, and (4) crossover to double-blind lisinopril or nifedipine. Measurements at the end of the four phases included 24-h blood pressure using the Accutracker, laboratory hemodynamics with the Dinamap and impedance cardiography, baroreflex sensitivity with the pneumatic neck chamber, and plasma samples for neurohumoral and metabolic activity. PATIENTS: Thirteen patients aged 55 years or older (mean +/- SEM 65 +/- 1 years) with mild-to-moderate hypertension completed the study. MAIN OUTCOME MEASURES: The primary data for analysis across the four study phases included ambulatory blood pressure values, laboratory hemodynamics, and baroreflex sensitivity. RESULTS: Compared with the preceding placebo, lisinopril and nifedipine lowered 24-h blood pressure significantly. In the laboratory, the effects of both compounds on blood pressure, cardiac output, calculated total systemic resistance, and the stroke volume-pulse pressure relationship, an index of arterial compliance, were similar. Lisinopril was associated with a relative increase in the standing systolic blood pressure compared with nifedipine (P < 0.05). This coincided with an enhanced heart-rate (R-R interval) response to neck pressure, which also decreased carotid transmural pressure, with lisinopril versus nifedipine (P < 0.05). CONCLUSIONS: Lisinopril and nifedipine were both effective as monotherapy for controlling blood pressure in these elderly patients. Despite similar effects on blood pressure and systemic hemodynamics, baroreflex sensitivity in response to a reduction in carotid transmural pressure was greater with lisinopril than with nifedipine.

Insulin does not reduce forearm alpha-vasoreactivity in obese hypertensive or lean normotensive men.

Evidence supports the hypothesis that an impaired capacity of insulin to antagonize norepinephrine-induced vasoconstriction increases alpha-adrenergic tone in overweight young men with insulin resistance and mild hypertension. Therefore, the effects of regionally infused insulin at 100 microU/mL on forearm blood flow (milliliters per deciliter per minute) and responses to norepinephrine were measured in seven obese hypertensive and eight lean normotensive men younger than 45 years old. The obese hypertensive men were hyperinsulinemic and insulin resistant compared with the normotensive men, as evidenced by abnormal values for fasting insulin (15.5 +/- 1.6 versus 7.2 +/- 0.8 microU/mL, P < .001), the insulin area under the curve in response to a 2-hour oral glucose tolerance test (12.0 +/- 1.5 versus 6.7 +/- 1.1 mU x min/dL, P < .01), and the disappearance rate of glucose during a 15-minute insulin tolerance test (2.7 +/- 0.3 versus 4.1 +/- 0.3 mg%/min, P < .05). The logarithm of the norepinephrine EC50 was not significantly different in obese hypertensive men (mean, 95% confidence interval: -8.15, -8.42 to -7.87) versus lean normotensive men (-7.91, -8.23 to -7.59). The 2-hour regional insulin infusion at 100 microU/mL did not significantly alter the EC50 for norepinephrine in either group. Insulin at this concentration induced significant and similar increases of forearm blood flow in the hypertensive and normotensive groups (1.7 +/- 0.4 versus 1.7 +/- 0.6 mL/100 mL per minute, P = NS). At approximately 100 microU/mL, insulin does not antagonize norepinephrine-induced vasoconstriction in the forearm circulation of either obese hypertensive or lean normotensive men.(ABSTRACT TRUNCATED AT 250 WORDS)

Outcomes of cardiopulmonary resuscitation in nursing homes: can we predict who will benefit?

PURPOSE: To determine the benefits of cardiopulmonary resuscitation (CPR) in nursing home patients and assess possible prearrest and arrest predictors of survival. PATIENTS AND METHODS: During a 4-year period (1986 to 1989), consecutive nursing home patients from Milwaukee, Wisconsin, who sustained cardiac arrest and received CPR by paramedics were studied. The patients' prearrest clinical characteristics were determined including age, length of stay in nursing home, medical diagnoses, medications, circumstances surrounding the arrest, laboratory studies, and baseline functional status. Cardiac arrest data were obtained from a paramedic computer data base and included whether the arrest was witnessed, initial cardiac rhythm, and success of CPR. Survival was defined as the discharge of the patient alive from the hospital, and the patient's pre- and post-arrest functional status was compared. Possible predictors of survival were analyzed from the patient's prearrest characteristics and arrest characteristics. RESULTS: Of the total 196 patients who received CPR, 37 (19%) were successfully resuscitated and hospitalized, and 10 (5%) survived to be discharged. However, 27% of patients survived whose arrests were witnessed and who demonstrated ventricular fibrillation at the time of the arrest. In comparison, only 2.3% of all other nursing home patients who received CPR survived (p < 0.0002). Age, mental or functional status, hematocrit, renal dysfunction, pulmonary disease, cancer, and cardiovascular disease were not significant predictors of survival. At the time of hospital discharge, the functional status of the majority (80%) of the survivors was comparable to their prearrest status and 40% of the survivors lived for greater than 12 months. CONCLUSION: We conclude that only a small percentage of nursing home patients who sustain cardiac arrest will benefit from CPR. However, greater than 25% of nursing home patients whose arrest is witnessed and who demonstrate ventricular fibrillation will survive. This is comparable to the survival rate of elderly community-dwelling persons who sustain cardiac arrest. Our data suggest that CPR should be initiated only in nursing home patients whose cardiac arrest is witnessed and should only be continued in patients whose initial documented cardiac rhythm is ventricular fibrillation or ventricular tachycardia.