Biomedical subjects

M Maddens

Publications and source records attributed to M Maddens.

5 recordsLinked to original sources

PubMed1989

Atrial natriuretic peptide attenuates the reflex sympathetic responses to lower body negative pressure.

The authors studied the effect of intravenous infusion of atrial natriuretic peptide (ANP) on the plasma catecholamine and forearm vasoconstrictor responses to cardiopulmonary baroreflex deactivation in six normal, male volunteers in order to determine whether ANP influences reflex forearm vasoconstriction in humans. Unloading of low-pressure cardiopulmonary baroreceptors (CPBR) was accomplished by application of low levels (-10 and -20 mm Hg) of lower body negative pressure (LBNP). The authors measured the plasma norepinephrine (NE) and epinephrine, the mean arterial pressure (MAP), and the forearm vascular resistance (FVR) responses to reflex sympathetic activation by LBNP. ANP infusion (0.1 microgram.kg-1.min-1) decreased (p less than 0.01) basal MAP, as well as plasma renin activity and plasma aldosterone levels (p less than 0.05). ANP infusion also reduced (p less than 0.01) plasma NE responses to both levels of LBNP and tended to decrease both epinephrine and FVR during ANP infusion at -20 mm Hg LBNP (p = 0.8). These data suggest that exogenous ANP inhibits the reflex sympathetic responses that occur with CPBR unloading. The blunted plasma NE responses to CPBR unloading parallel the attenuation of FVR response to LBNP during ANP infusion, despite significant LBNP-induced hypotension.

Adult↗

PubMed1987

Impaired heart rate responses to cough and deep breathing in elderly patients with unexplained syncope.

To test the hypothesis that elderly patients with unexplained syncope have impaired autonomic control of heart rate, chronotropic responses to deep breathing and cough were studied in 12 elderly patients (85 +/- 4 years), 14 elderly control subjects (82 +/- 7 years) and 10 young subjects (26 +/- 5 years). There was no difference in resting RR interval between elderly patients with syncope and control subjects. However, the ratio of the maximum RR/minimum RR (an index of heart rate variability) during deep breathing was significantly lower in patients than in control subjects (p less than 0.005). In the minute following cough, there was no difference in initial reflex tachycardia, but subsequent rebound bradycardia was blunted in the elderly patients with syncope. The predominant impairment in elderly patients with unexplained syncope was the bradycardia component of the responses to deep breathing and cough, suggesting that these patients may have impaired parasympathetic modulation of heart rate. Although not likely to be the cause of syncope in these patients, these findings may reflect an underlying autonomic defect.

Aged↗

PubMed1987

Catecholamines in critical care.

Catecholamines (norepinephrine, epinephrine, and dopamine) are released into circulation in response to stress and injury and as part of the body's attempt at vasoregulation in response to circulatory failure. Norepinephrine is released from sympathetic nerve terminal, and epinephrine and dopamine are released from the adrenal medulla. Plasma levels of these catecholamines have been reported to be elevated in various clinical settings: congestive heart failure, myocardial infarction, cardiopulmonary bypass, diabetic ketoacidosis, hypoxia, hemorrhage, and septic shock. These amines have both beneficial and detrimental effects on survival. Both norepinephrine and dopamine are often employed in the critically ill to selectively increase cardiocerebral and renal blood flow, respectively.

Animals↗

PubMedDate not supplied

Eye care in the skilled nursing facility: a pilot study of prevalence and treatment patterns of glaucoma.

OBJECTIVE: The objective of this study was to determine the rates of ophthalmic examinations for glaucoma, prevalence rates of glaucoma, ongoing evaluation (follow-up) rates and rates of treatment for a population of residents in a skilled nursing facility. DESIGN: We conducted a retrospective evaluation and chart review of glaucoma-related ophthalmology services. SETTING: This study was conducted in a skilled nursing facility located in a large metropolitan area located in the Midwest. PARTICIPANTS: We studied all nursing home residents of the facility on October 1, 2002 (n = 160). METHODS: We conducted a retrospective evaluation and chart review of glaucoma-related ophthalmology services for 160 patients. The medical records used for review included admission records, physician history and physical records, hospital notes, nursing assessments, consultation notes, and medication reviews (including medications administered during hospital stays). Minimum data set (MDS) data and individual patient interviews were used to supplement and verify chart abstraction findings. RESULTS: Eighty-three residents (52%) had evidence of assessment for glaucoma. Thirty-three of these residents (40%) had documentation of a diagnosis of glaucoma; 25 (76%) had current treatment orders for a topical ophthalmic agent. Nine patients were using combination therapy; four used topical and oral beta-adrenergic-blocking agents. CONCLUSIONS: Visual impairment remains a serious problem for nursing facility residents. Assessment of visual abilities is infrequent or nonexistent. Education for nursing home personnel, discussion and activation among nursing home thought leaders, and guidelines for the evaluation and management of glaucoma in this care environment are needed.

Adrenergic beta-Antagonists↗

PubMedDate not supplied

Prevalence of Staphylococcus aureus carriage among asymptomatic nursing home personnel: a pilot study.

OBJECTIVES: To determine the carriage rate of Staphylococcus aureus (SA), both methicillin sensitive, and methicillin resistant (MRSA), among employees of a nursing home in the absence of an epidemic. DESIGN: Observational study. SETTING: A 210-bed suburban skilled nursing facility with a low endemic rate of SA infection. PARTICIPANTS: Seventy-three asymptomatic employees recruited in two waves. MEASUREMENT: Nasal swabs were cultured for SA; DNA strain typing was performed on MRSA isolates from the first wave of recruits. RESULTS: 21 of 73 (29%) cultures were positive for SA. Ten of these 21 (14% of participating employees) had nasal carriage of MRSA. MRSA carriage was not significantly correlated with age, duration of employment, or job type (clinical vs. non-clinical), and DNA strain typing suggested that employee carriage of MRSA was not the result of a common source. CONCLUSIONS: Staphylococcus aureus nasal carriage is common among skilled nursing facility personnel, and MRSA accounts for a substantial proportion of SA carriage among employees, even in the absence of an epidemic. Further research is needed to determine whether the high SA carriage rates among employees reflects work place acquisition, and, if so, whether it poses a hazard to the employees. The low incidence of nosocomial MRSA infections around the time of the study suggests that with usual infection control practices (eg, hand washing), MRSA-colonized caregivers pose little risk to nursing facility residents.

Journal Article↗