Critical care : the official journal of the Critical Care Forum
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Simple methods to predict the effect of lung recruitment maneuvers (LRMs) in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are lacking. It has previously been found that a static pressure-volume (PV) loop could indicate the increase in lung volume induced by positive end-expiratory pressure (PEEP) in ARDS. The purpose of this study was to test the hypothesis that in ALI (1) the difference in lung volume (DeltaV) at a specific airway pressure (10 cmH2O was chosen in this test) obtained from the limbs of a PV loop agree with the increase in end-expiratory lung volume (DeltaEELV) by an LRM at a specific PEEP (10 cmH2O), and (2) the maximal relative vertical (volume) difference between the limbs (maximal hysteresis/total lung capacity (MH/TLC)) could predict the changes in respiratory compliance (Crs), EELV and partial pressures of arterial O2 and CO2 (PaO2 and PaCO2, respectively) by an LRM. ⋯ A PV-loop-derived parameter, MH/TLC of 0.3, predicted changes in lung mechanics better than changes in gas exchange in this lung injury model.
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Editorial Comment
The essential nature of healthcare databases in critical care medicine.
Medical databases serve a critical function in healthcare, including the areas of patient care, administration, research and education. The quality and breadth of information collected into existing databases varies tremendously, between databases, between institutions and between national boundaries. The field of critical care medicine could be advanced substantially by the development of comprehensive and accurate databases.
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Editorial Comment
Are platelets a 'forgotten' source of sepsis-induced myocardial depressing factor(s)?
The mechanism of sepsis-induced cardiac failure was initially thought to be related to the presence of 'myocardial depressant' substances that directly alter heart function. Exosomes released by platelets and identified in the plasma are suggested to, at least partially, explain myocardial depression in sepsis. This hypothesis needs to be evaluated by clinical studies.
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The current gold standard for the diagnosis of elevated intracranial pressure (ICP) remains invasive monitoring. Given that invasive monitoring is not always available or clinically feasible, there is growing interest in non-invasive methods of assessing ICP using diagnostic modalities such as ultrasound or magnetic resonance imaging (MRI). ⋯ They report a positive correlation between measurements of the ONSD on MRI and invasive ICP measurements. If the findings of this study can be replicated in larger populations, this technique may be a useful non-invasive screening test for elevated ICP in select populations.
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Editorial Comment
Insulin, intracerebral glucose and bedside biochemical monitoring utilizing microdialysis.
Following subarachnoid hemorrhage, hyperglycemia is strongly associated with complications and with impaired neurological recovery. Targeted insulin therapy for glycemic control might, on the contrary, have harmful effects by causing too low cerebral glucose levels. The study published by Schlenk and colleagues in the previous issue of Critical Care shows that insulin caused a significant decrease in the interstitial cerebral glucose concentration although the blood glucose level remained unaffected. Since several studies utilizing various analytical techniques have shown that cerebral blood flow and cerebral glucose uptake and metabolism are insulin-independent processes, the observation remains unexplained.