Heart & lung : the journal of critical care
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Limited data are available on the efficacy of a common endotracheal suctioning intervention to prevent decreases in arterial oxygenation (PaO2) after endotracheal suctioning. We evaluated the effect of five hyperinflation breaths with hyperoxygenation, administered before and after endotracheal tube suctioning, in anesthetized, paralyzed sheep with normal lung function and with abnormal lung function induced by pulmonary acid aspiration. Using a second ventilator to deliver hyperinflation and hyperoxygenation prevented PaO2 from falling below control values after endotracheal tube suctioning in animals with either normal or abnormal lung function. ⋯ These results highlight the difference in PaO2 response when hyperinflation and hyperoxygenation suctioning interventions are delivered with mechanical versus manual techniques. These results also emphasize that the response to hyperinflation and hyperoxygenation differs in subjects with normal versus abnormal lung function. Laboratory evaluation of endotracheal tube suctioning interventions should use abnormal lung function models, rather than normal lung function models, to approximate more closely the critically ill patient population that requires suctioning.
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Comparative Study
Minimum discard volume from arterial catheters to obtain coagulation studies free of heparin effect.
With the use of the canine experimental model, the accuracy and reliability of coagulation test results were compared between arterial samples and samples obtained by venipuncture. The age of the catheter, the concentration of the heparinized flush solution, and the minimum discard volume were evaluated to obtain coagulation study results free of heparin effect. ⋯ Analyses revealed no significant difference in test results between new lines and 7-day-old lines, nor between heparin concentrations of 1 unit/ml, 2 units/ml, or 4 units/ml. A minimum discard volume of five times the dead space (measured from catheter tip to sampling proximal stopcock) resulted in accurate and reliable PT, aPTT, and TT test results from the arterial catheters.
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By consensus, the most clinically important consequence of near drowning is hypoxemia. Whether it is due to physiologic shunting induced by diffuse alveolar flooding from saltwater aspiration or to diffuse atelectasis induced by surfactant inactivation from freshwater aspiration, both physiologic disturbances can be reversed with the institution of positive-pressure breathing in the form of PEEP or CPAP, which should be the mainstay of pulmonary management of respiratory insufficiency in these patients. The use of prophylactic antibiotics or corticosteroids as an adjunct in the management of pulmonary insufficiency resulting from near drowning is not warranted, may be detrimental, and remains controversial. ⋯ A significant subset of comatose near-drowning victims survive with eventually normal neurologic recovery when routine aggressive supportive intensive care is administered. Uncontrolled studies reporting improved outcomes with the institution of complex cerebral salvage techniques, such as induction of hypothermia, intracerebral pressure monitoring, induction of barbiturate coma, and the use of corticosteroids and osmotic diuretics, remain controversial. It is now clear that neither induced hypothermia nor barbiturate coma improves survival or neurologic outcome in these patients and may be detrimental.(ABSTRACT TRUNCATED AT 250 WORDS)