Critical care : the official journal of the Critical Care Forum
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Comment
Magnesium sulfate for aneurysmal subarachnoid hemorrhage: the end of the road or more trials?
Delayed cerebral ischemia (DCI) is a feared complication and an important cause of poor outcome after aneurysmal subarachnoid hemorrhage (SAH). In the current study, Wong and colleagues performed a systematic review and meta-analysis of randomized controlled trials that investigated the efficacy of magnesium sulfate in patients with aneurysmal SAH. Outcome measures were DCI, cerebral infarction, and functional outcome 3 and 6 months after SAH. ⋯ Clinical deterioration due to DCI is more subject to inter-observer bias compared to cerebral infarction, which represents the ultimate outcome of the ischemic event. The Magnesium in Aneurysmal Subarachnoid Hemorrhage-II (MASH-II: ISRCTN68742385) phase III clinical trial nears completion. It aims to include 1,200 patients, and its results are urgently awaited.
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Cardiac arrest following trauma occurs infrequently compared with cardiac aetiology. Within the German Resuscitation Registry a traumatic cause is documented in about 3% of cardiac arrest patients. Regarding the national Trauma Registry, only a few of these trauma patients with cardiac arrest survive. The aim of the present study was to analyze the outcome of cardiopulmonary resuscitation (CPR) after traumatic cardiac arrest by combining data from two different large national registries in Germany. ⋯ Our present study encourages CPR attempts in cardiac arrest patients following severe trauma. When a manageable number of patients is present, the decision on whether to start CPR or not should be done liberally, using comparable criteria as in patients with cardiac etiology. In this respect, trauma management programs that restrict CPR attempts should not be encouraged.
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Marked variability in transfusion practice exists in cardiac surgical patients, with consumption of approximately 20% of the worldwide allogeneic blood supply. Observational studies have reported an association between red blood cell transfusion and adverse outcome, including pulmonary complications, in cardiac surgery. ⋯ This study provides interesting preliminary data, but is limited by multiple confounding variables (plasma transfusion, use of anticoagulants and heparin antagonists) and the small sample size. A large multicenter, prospective, randomized clinical trial regarding the safety (inclusive of pulmonary complications) and efficacy of red blood cell transfusion in cardiac surgery is needed.
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Assessment of vasomotor tone is essential in defining appropriate resuscitation strategies for the hypotensive patient. Although changes in mean arterial pressure to cardiac output define arterial resistance, resistance is only one component of vasomotor tone. Compliance is the other component. ⋯ Dynamic Ea is only one component of vasomotor tone, however, and increases in pulse pressure may not be proportional to increases in mean arterial pressure. Also, devices that use the arterial pressure pulse to calculate the stroke volume have an inherent bias that is different amongst devices based on their transfer function algorithms. The use of dynamic Ea for clinical decision-making thus needs to be validated separately for different devices and types of patients.
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Pleth Variability Index (PVI) is an automated and continuous calculation of respiratory variations in the perfusion index. PVI correlates well with respiratory variations in pulse pressure (ΔPP) and is able to predict fluid responsiveness in the operating room. ICU patients may receive vasopressive drugs, which modify vascular tone and could affect PVI assessment. We hypothesized that the correlation between PVI and ΔPP and the ability of PVI to identify patients with ΔPP > 13% is dependent on norepinephrine (NE) use. ⋯ Our results suggest that in mechanically ventilated adult patients, NE alters the correlation between PVI and ΔPP and the ability of PVI to predict ΔPP > 13% in ICU patients.