IntroductionThe aim of this study was to develop consensus recommendations on safety parameters for mobilizing adult, mechanically ventilated, intensive care unit (ICU) patients.MethodsA systematic literature review was followed by a meeting of 23 multidisciplinary ICU experts to seek consensus regarding the safe mobilization of mechanically ventilated patients.ResultsSafety considerations were summarized in four categories: respiratory, cardiovascular, neurological and other. Consensus was achieved on all criteria for safe mobilization, with the exception being levels of vasoactive agents. Intubation via an endotracheal tube was not a contraindication to early mobilization and a fraction of inspired oxygen less than 0.6 with a percutaneous oxygen saturation more than 90% and a respiratory rate less than 30 breaths/minute were considered safe criteria for in- and out-of-bed mobilization if there were no other contraindications. At an international meeting, 94 multidisciplinary ICU clinicians concurred with the proposed recommendations.ConclusionConsensus recommendations regarding safety criteria for mobilization of adult, mechanically ventilated patients in the ICU have the potential to guide ICU rehabilitation whilst minimizing the risk of adverse events.

Nitric oxide (NO) appears to play a role in contraction-stimulated glucose uptake in isolated rodent skeletal muscle; however, no studies have examined this question in humans. Seven healthy men completed two 30-min bouts of supine cycling exercise at 60 +/- 2% peak pulmonary oxygen uptake (VO2 peak), separated by 90 min of rest. The NO synthase inhibitor N(G)-monomethyl-L-arginine ([L-NMMA]; total dose 5 mg/kg body weight) or saline (control) were administered via the femoral artery for the final 20 min of exercise in a randomized blinded crossover design. L-Arginine (5 mg/kg body weight) was co-infused during the final 5 min of each exercise bout. Leg blood flow (LBF) was measured by thermodilution in the femoral vein, and leg glucose uptake was calculated as the product of LBF and femoral arteriovenous (AV) glucose difference. L-NMMA infusion significantly (P < 0.05) reduced leg glucose uptake compared with control (48 +/- 12% lower at 15 min, mean +/- SE). The reduction in glucose uptake was due solely to a decrease in AV glucose difference, as there was no effect of L-NMMA infusion on LBF during exercise. Co-infusion of L-arginine restored glucose uptake during L-NMMA infusion to levels similar to control. These results indicate that NO production contributes substantially to exercise-mediated skeletal muscle glucose uptake in humans independent of skeletal muscle blood flow.

OBJECTIVE -Diabetic individuals have impaired endothelium-dependent forearm vasodilatory responses to ischemia, acetylcholine, and other endothelium-dependent agonists. The functional significance of impaired endothelium-dependent dilation in diabetic individuals is uncertain but is most likely to be manifest during leg muscle exercise and may have relevance to peripheral vascular disease and leg ischemia, which is prevalent in diabetic individuals. The current study aimed to determine the relationship between leg blood flow (LBF) responses to endothelium-dependent vasodilation and dynamic large muscle exercise. RESEARCH DESIGN AND METHODS -LBF responses (thermodilution)to intrafemoral arterial infusions of an endothelium-dependent (acetylcholine) and endotheliumindependent (sodium nitroprusside) vasodilator and a standardized 25-min cycling bout at 60% VO 2peak were compared in nine male type 2 diabetic subjects and nine age-, sex-, VO 2peak -, and weight-matched control subjects.RESULTS -LBF responses to acetylcholine and exercise but not sodium nitroprusside were significantly (P Ͻ 0.05) attenuated in patients with diabetes compared with healthy control subjects. The percentage increase in LBF in response to exercise and acetylcholine were significantly correlated (r ϭ 0.54, P ϭ 0.02). Furthermore, resting plasma glucose was significantly related to the LBF response to exercise (r ϭ Ϫ0.66, P ϭ 0.003) independently of insulin, HbA 1c , lipids, BMI, and blood pressure.CONCLUSIONS -The increase in LBF during exercise is substantially attenuated in type 2 diabetic compared with matched control subjects. Impaired endothelium-dependent vasodilation secondary to elevated plasma glucose may underlie this observation. This mechanism may be of importance in determining the leg ischemic threshold in diabetic individuals with peripheral vascular disease. Diabetes Care 26:899 -904, 2003

Nitric oxide (NO) synthase inhibition reduces leg glucose uptake during cycling without reducing leg blood flow (LBF) in young, healthy individuals. This study sought to determine the role of NO in glucose uptake during exercise in individuals with type 2 diabetes. Nine men with type 2 diabetes and nine control subjects matched for age, sex, peak pulmonary oxygen uptake (VO 2 peak), and weight completed two 25-min bouts of cycling exercise at 60 ؎ 2% VO 2 peak, separated by 90 min. N G -monomethyl-L-arginine (L-NMMA) (total dose 6 mg/kg) or placebo was administered into the femoral artery for the final 15 min of exercise in a counterbalanced, blinded, crossover design. LBF was measured by thermodilution in the femoral vein, and leg glucose uptake was calculated as the product of LBF and femoral arteriovenous glucose difference. During exercise with placebo, glucose uptake was not different between control subjects and individuals with diabetes; however, LBF was lower and arterial plasma glucose and insulin levels were higher in individuals with diabetes. L-NMMA had no effect on LBF or arterial plasma glucose and insulin concentrations during exercise in both groups. L-NMMA significantly reduced leg glucose uptake in both groups, with a significantly greater reduction (P ‫؍‬ 0.04) in the diabetic group (75 ؎ 13%, 5 min after L-NMMA) compared with the control group (34 ؎ 14%, 5 min after L-NMMA). These data suggest a greater reliance on NO for glucose uptake during exercise in individuals with type 2 diabetes compared with control subjects.

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