Anesthesia and analgesia
-
Anesthesia and analgesia · Oct 2003
The effect of sevoflurane and propofol on cerebral neurotransmitter concentrations during cerebral ischemia in rats.
Sevoflurane and propofol are neuroprotective possibly by attenuating central or peripheral catecholamines. We evaluated the effect of these anesthetics on circulating catecholamines and brain neurotransmitters during ischemia in rats. Forty male Sprague-Dawley rats were randomly assigned to one of the following treatment groups: fentanyl and N(2)O/O(2) (control), 2.0% sevoflurane, 0.8-1.2 mg x kg(-1) x min(-1) of propofol, and sham-operated rats with fentanyl and N(2)O/O(2). Ischemia (30 min) was produced by unilateral common carotid artery occlusion plus hemorrhagic hypotension to a mean arterial blood pressure of 32 +/- 2 mm Hg. Pericranial temperature, arterial blood gases, and pH value were maintained constant. Cerebral catecholamine and glutamate concentrations, sampled by microdialysis, and plasma catecholamine concentrations were analyzed using high-pressure liquid chromatography. During ischemia, circulating catecholamines were almost completely suppressed by propofol but only modestly decreased with sevoflurane. Sevoflurane and propofol suppressed brain norepinephrine concentration increases by 75% and 58%, respectively, compared with controls. Intra-ischemia cerebral glutamate concentration was decreased by 60% with both sevoflurane and propofol. These results question a role of circulating catecholamines as a common mechanism for cerebral protection during sevoflurane and propofol. A role of brain tissue catecholamines in mediating ischemic injury is consistent with our results. ⋯ During incomplete cerebral ischemia, the neuroprotective anesthetics sevoflurane and propofol suppressed cerebral increases in norepinephrine and glutamate concentrations. In contrast, propofol, but not sevoflurane, suppressed the ischemia-induced increase in circulating catecholamines to baseline levels. The results question a role for plasma catecholamines in cerebral ischemic injury.
-
Anesthesia and analgesia · Oct 2003
Review Meta AnalysisInhaled nitric oxide for acute hypoxic respiratory failure in children and adults: a meta-analysis.
We systematically reviewed randomized controlled trials examining inhaled nitric oxide (INO) for the treatment of acute respiratory distress syndrome or acute lung injury in children and adults. Qualitative assessments of identified trials were made, and metaanalyses were performed according to Cochrane methodology. Five randomized controlled trials (n = 535) met entry criteria. ⋯ Other clinical indicators of effectiveness, such as duration of hospital and intensive care stay, were inconsistently reported. Lack of data prevented assessment of all outcomes. If further trials assessing INO in acute respiratory distress syndrome or acute lung injury are to proceed, they should be stratified for primary etiology, incorporate other modalities that may affect outcome, and evaluate clinically relevant outcomes before any benefit of INO can be excluded.