Objective: This study determined the mechanisms and time-course of recovery of vascular relaxation in middle cerebral arteries (MCA) of salt-fed Sprague-Dawley rats returned to low salt (LS) diet (0.4% NaCl) or infused with low-dose angiotensin II (ANG II).Methods: Rats were fed high salt (HS) diet (4% NaCl) for 3 days or 4 weeks before return to LS diet for various periods. Other rats fed HS diet (HS + ANG II) received a chronic (3 days) i.v. infusion of a low dose of ANG II (5 ng·kg −1 ·min −1 ) to prevent salt-induced ANG II suppression.Results: HS diet eliminated the increase in cerebral blood flow in response to acetylcholine (ACh) infusion and the relaxation of MCA in response to ACh, iloprost, cholera toxin, and reduced PO 2 . Recovery of vascular relaxation was slow, requiring at least 2 weeks of LS diet, regardless of the duration of exposure to HS diet. Hypoxic dilation was mediated by cyclooxygenase metabolites and ACh-induced dilation was mediated via NO in LS rats and in HS rats returned to LS diet or receiving ANG II infusion.
Conclusions:Return to LS diet for 2 weeks or chronic 3-day ANG II infusion restore the mechanisms that normally mediate cerebral vascular relaxation.
Conservative management for the majority of patients with severe chest injuries has produced a reduction in mortality, complications, and hospital length of stay. More recently, operative stabilization of rib fractures has been used with the implication of improved outcome. We assessed the impact of operative rib fracture stabilization on outcome among trauma patients. A matched case-control study of patients undergoing operative rib fracture stabilization was performed. Thirty patients undergoing rib stabilization were matched with 30 controls. Length of intensive care unit (controls, 14.1 ± 2.7 vs cases, 12.1 ± 1.2, P = 0.51) and total hospital (controls, 21.1 ± 3.9 vs cases, 18.8 ± 1.8, P = 0.59) stay were similar for both groups. There was a trend toward fewer total ventilator days for operative patients (6.5 ± 1.3 days vs 11.2 ± 2.6 days, P = 0.12). Ventilator days for operative patients from the time of stabilization was 2.9 ± 0.6 days compared with 9.4 ± 2.7 days in controls (P = 0.02). Rib fracture fixation may reduce ventilator requirements in trauma patients with severe thoracic injuries. Long-term functional outcomes need to be assessed to ascertain the impact of this procedure.
This pilot study indicates that intermittent IV pantoprazole effectively controls gastric pH and may protect against UGI bleeding in high risk ICU patients without the development of tolerance.
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