Anesthesiology
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Comparative Study
Effects of ketamine, halothane, enflurane, and isoflurane on systemic and splanchnic hemodynamics in normovolemic and hypovolemic cirrhotic rats.
The effects of ketamine, halothane, enflurane, and isoflurane on systemic and splanchnic hemodynamics in cirrhotic rats that were either normovolemic or hypovolemic following hemorrhage were characterized. Rats received at random either ketamine (30 mg/kg iv, 1.5 mg.kg-1.min-1 iv), halothane, enflurane, or isoflurane (1 MAC). Conscious rats were considered the control group. ⋯ After hemorrhage portal venous tributary blood flow decreased significantly in all groups except in enflurane group. During halothane and enflurane anesthesia hepatic arterial blood flow and hepatic arterial fraction of cardiac output decreased (P less than 0.01) and they were maintained in the other groups. After hemorrhage hepatic arterial fraction of cardiac output in conscious rats was higher than in those receiving ketamine, halothane, or enflurane (P less than 0.05) and was similar to those receiving isoflurane.(ABSTRACT TRUNCATED AT 250 WORDS)
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Because currently available blood warmers are inadequate for infants and children requiring massive transfusion, the performance of a new high-efficiency pediatric blood warmer (System 250TM, LEVEL 1 Technologies Inc., Marshfield, Massachusetts) was evaluated and compared with a commonly used conventional blood warmer (Model DW1000A, American Pharmaseal, Valencia, California). Cold (5-6 degrees C), diluted red blood cells (RBC) (Hct = 30%) were infused through the warmers over a series of flow rates, and the resulting temperatures of the infusate were measured. The flow rates of diluted packed RBC were also measured over a series of infusion pressures. ⋯ Above a flow rate of 250 ml/min, however, the water bath of the System 250TM cooled significantly, resulting in a deterioration of performance and an output temperature of only 24.2 degrees C at a flow rate of 400 ml/min. With a 16-G catheter attached, the flow rate at a pressure of 300 mmHg was 223 ml/min through the System 250TM compared with 160 ml/min (P less than 0.05) for the conventional warmer. The System 250TM produced higher output temperatures and a lower resistance to flow compared with the conventional warmer, but flow rates of cold blood through the System 250TM should be restricted to 250 ml/min or less to ensure adequate warming.