No description available.

Many senescent individuals demonstrate an inability to regulate mean arterial pressure (MAP) in response to standing or head-up tilt; however, whether this aging effect is the result of depressed cardiac function or an inability to reduce peripheral vascular conductance remains unknown. Therefore, the purpose of this research was to investigate the effects of aging on MAP, heart rate (HR), regional blood flow (via radioactive-microspheres), and vascular conductance during head-up tilt in conscious young (4 mo; n=12) and old (24 mo; n=10) male Fischer-344 rats. Heart rate and MAP were measured continuously during normal posture and during 10 minutes of head-up tilt. Blood flow was determined during normal posture and at the end of 10 minutes of head-up tilt. Young rats increased MAP significantly at the onset of head-up tilt and generally maintained the increase in MAP for the duration of head-up tilt, while aged rats showed a significant reduction in MAP after 10 minutes of head-up tilt. In the normal posture, aged rats demonstrated lower blood flow to splanchnic, bone, renal, and skin tissues versus young rats. With tilt there were decreases in blood flow to skin, bone, and hind-limb in both age groups and in fat, splanchnic, reproductive, and renal tissues in the young. Bone blood flow was attenuated with age across both conditions in hind foot, distal femur, femur marrow, and proximal and distal tibia. Head-up tilt caused a decrease in blood flow across both age groups in all bones sampled with the exception of the hind foot. These results provide evidence that the initial maintenance of MAP in aged rats during head-up tilt occurs through decreased regional blood flow and vascular conductance, and that the fall in pressure is not attributable to an increase in tissue blood flow and vascular conductance. Therefore, reductions in arterial pressure during headup tilt are likely a result of an old age-induced reduction in cardiac performance. In addition, this is the first study to demonstrate a decreased bone vascular conductance in both young and old rats during head-up tilt.

Thèse de doctorat : Ingénierie cellulaire et tissulaire : Nancy 1 : 2009. / Titre provenant de l'écran-titre.

Thesis (MPhysio)--University of South Australia, 1998

Thesis (Ph. D.)--University of Oregon, 2007. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 196-214). Also available for download via the World Wide Web; free to University of Oregon users.

Academisch Proefschrift--Universiteit van Amsterdam, 2007. / Includes bibliographical references (p. 91-108).

Th.--Méd.--Paris, 1907-1908. / Paris, 1907-1908, t. 41, n ° 222.

M.Tech.

No description available.

BACKGROUND: Early postoperative cardiovascular complication rates are high and are associated with hemodynamic compromise. A large proportion of hypotensive episodes are missed with routine ward monitoring strategies due to low measurement frequency and nursing limitations. OBJECTIVES: The aim of this study was to determine the incidence of postoperative hypotension using a frequent monitoring strategy. Second, we looked at the relationship between postoperative hypotension and composite of mortality, non-fatal myocardial infarction, non-fatal stroke and new dialysis requirements. Finally, we sought to uncover significant predictors of postoperative hypotension. METHODS: Patients >45-years of age enrolled in the VISION Study were included in this sub-study. The COVIDIEN vital sign monitor was used to collect blinded hourly blood pressure measurements in patients post non-cardiac surgery until post-operative day three. RESULTS: 1248 patients were included in this analysis. The three-day incidence of hypotension in the compliant intensively monitored group was almost twice higher (31.4% - 81/258 patients) than in the routine monitoring group, and the average delay in identifying a drop in BP under 90mmHg was almost 1.5 hours (87.5min) (IQR 21.3-153.3min). Severe hypotension (SBP <80mmHg) in the first three postoperative days, had the strongest association amongst all perioperative factors with the composite outcome of death, MI, stroke and new requirement for dialysis after non-cardiac surgery at 30 days [adjusted OR of 2.83 (95%CI, 1.25-6.44)]. Significant predictors of postoperative hypotension include a history of dialysis [adjusted OR 3.1 (95%CI, 1.14-12.96)], open surgery [adjusted OR 2.39 (95%CI, 1.57-3.62)], abdominal surgery [adjusted OR 1.79 (95%CI, 1.25-2.57)], and orthopedic surgery [adjusted OR 1.72 (95%CI, 1.112.74)]. CONCLUSION: Early postoperative cardiovascular complication rates are high and are associated with hemodynamic compromise. A large proportion of hypotensive episodes are missed with routine ward monitoring strategies. / Thesis / Master of Science (MSc)