Critical care medicine
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Critical care medicine · Jul 1996
Randomized Controlled Trial Clinical TrialCerebrospinal fluid and plasma nitrite and nitrate concentrations after head injury in humans.
To measure cerebrospinal fluid and plasma nitrite and nitrate concentrations as indicators of nitric oxide production in adults after severe closed-head injury. To determine if there is an association between cerebrospinal fluid and plasma nitrite and nitrate concentrations, and cerebral blood flow, arterio-jugular oxygen content difference, injury severity, and outcome after severe closed-head injury. ⋯ Increases in cerebrospinal fluid nitrite and nitrate concentrations peaked at 30 to 42 hrs after severe closed-head injury. This increase in cerebrospinal fluid nitrite and nitrate concentrations was greater in nonsurvivors. Also, cerebrospinal fluid and plasma nitrite and nitrate concentrations were associated with injury Severity Score, suggesting that increased nitric oxide production in the brain is associated with injury severity and death. Hypothermia did not prevent the increase in cerebrospinal fluid nitrite and nitrate concentrations. Further study is required to determine the source of this increase in cerebrospinal fluid nitrite and nitrate concentrations and to further define the relationship to outcome and the effect of hypothermia on this process.
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Critical care medicine · Jul 1996
Randomized Controlled Trial Clinical TrialRenal hemodynamics during norepinephrine and low-dose dopamine infusions in man.
To characterize the effects of pressor doses of norepinephrine and low-dose dopamine (3 micrograms/kg/min) on renal hemodynamics in man, as well as to determine the clinical relevance of combining dopamine with norepinephrine. ⋯ The addition of dopamine (3 micrograms/kg/min) to pressor doses of norepinephrine normalized renal blood flow in healthy volunteers. These hemodynamic changes were not reflected in urine output and glomerular filtration rate; hence, these monitoring parameters may be unreliable indicators of renal function in the setting of vasopressor therapy. In addition, systemic effects were observed with dopamine (3 micrograms/kg/min), as indicated by a decrease in MAP.
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Critical care medicine · Jul 1996
Randomized Controlled Trial Clinical TrialEffects of heat and moisture exchangers on minute ventilation, ventilatory drive, and work of breathing during pressure-support ventilation in acute respiratory failure.
To evaluate the effect of two commonly used heat and moisture exchangers on respiratory function and gas exchange in patients with acute respiratory failure during pressure-support ventilation. ⋯ The tested heat and moisture exchangers should be used carefully in patients with acute respiratory failure during pressure-support ventilation, since these devices substantially increase minute ventilation, ventilatory drive, and work of breathing. However, an increase in pressure-support ventilation (5 to 10 cm H2O) may compensate for the increased work of breathing.
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Critical care medicine · Jul 1996
Mediastinal tube placement in children with pneumomediastinum: hemodynamic changes and description of technique.
To describe the technique, hemodynamic response, and complication rate after the insertion of a percutaneous mediastinal tube for drainage of pneumomediastinum. ⋯ These findings suggest that hemodynamic compromise commonly accompanies pneumomediastinum in children. Decompression of the mediastinal space and drainage of the pneumomediastinum, using this simple bedside technique for continuous drainage, can be performed rapidly and safely in children, resulting in immediate hemodynamic improvement, and allowing for continuous drainage.
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Critical care medicine · Jul 1996
Comparative StudyCerebral effects of resuscitation with hypertonic saline and a new low-sodium hypertonic fluid in hemorrhagic shock and head injury.
A 2400-mOsm/L hypertonic solution (isosal) with a lower sodium content, compared with conventional 7.5% hypertonic saline, was formulated using a mixture of sodium chloride, glucose, and mixed amino acids. This solution was developed to minimize hypernatremia during resuscitation. We assessed the effects of isosal on hemodynamics, brain edema, and plasma sodium concentration after head injury associated with hemorrhagic shock. DESIGN. Prospective, randomized laboratory study. ⋯ After combined head injury and shock, isosal and 7.5% hypertonic saline have similar effects on hemodynamics and intracranial pressure. Hypertonic saline induces a greater degree of brain dehydration; isosal resuscitation results in smaller increases in plasma sodium.