Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1998
0.45% saline and 5% dextrose in water, but not 0.9% saline or 5% dextrose in 0.9% saline, worsen brain edema two hours after closed head trauma in rats.
In this study, we examined the effect of four i.v. fluids (250 mL/kg) on blood glucose and osmolality and brain tissue specific gravity after closed head trauma (CHT) in rats. CHT was delivered at Time 0; blood was sampled at 60 min; fluid infusion began at 75 min and ended at 105 min. Blood was again sampled at 105 and 120 min, and brain tissue specific gravity was determined at 120 min. Five groups (one control and four fluid-treated groups) received CHT, and five other groups (one control and four fluid-treated) did not (n = 9 in each group). 0.45% saline (1/2 NS) and 5% dextrose in water (D5W) accentuated the decrease of brain tissue specific gravity (1.0366 +/- 0.0025 and 1.0368 +/- 0.0028, respectively; mean +/- SD) caused by CHT (1.0395 +/- 0.0036), but 5% dextrose in 0.9% saline (D5NS) and 0.9% saline (NS) did not (1.0431 +/- 0.0042 and 1.0389 +/- 0.0049, respectively). In addition, 1/2 NS decreased blood osmolality (248 +/- 6 mOsm/L), D5W increased blood glucose (1095 +/- 173 mg/dL), D5NS increased blood osmolality (350 +/- 5 mOsm/L) and glucose (1695 +/- 76 mg/dL), and NS caused no significant change. We conclude that administering hypoosmolar i.v. fluids after CHT causes a significant worsening of cerebral edema 2 h after CHT. ⋯ We previously reported worse neurological outcome and/or mortality after closed head trauma in rats when 5% dextrose in water or 0.45% saline was given i.v. compared with 0.9% saline or 5% dextrose in 0.9% saline. The present results and our previous findings indicate that worsening of outcome after closed head trauma in rats may be caused more by edema formation than by hyperglycemia.
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Anesthesia and analgesia · Jun 1998
Comparative StudyThe effects of propofol on cerebral blood flow velocity and cerebral oxygen extraction during cardiopulmonary bypass.
We investigated the effects of burst-suppression doses of propofol on cerebral blood flow velocity (CBFV), cerebral oxygen extraction (COE), and dynamic autoregulation in 20 patients undergoing cardiac surgery. The experimental procedure was performed during nonpulsatile cardiopulmonary bypass (CPB) with stable hypothermia (32 degrees C) in fentanyl-anesthetized patients. Middle cerebral artery transcranial Doppler flow velocity, right jugular bulb oxygen saturation, and jugular venous pressure (JVP) were continuously measured. Dynamic autoregulation was tested by stepwise changes in mean arterial pressure (MAP) within a range of 40-80 mm Hg by sodium nitroprusside and phenylephrine before (control) and during propofol infusion, with a stable plasma concentration (approximately 9 microg/mL). Propofol induced a 35% decrease in CBFV (P < 0.0001) and a 10% decrease in COE (P < 0.05) compared with control. The slopes of the curves relating CBFV and COE to cerebral perfusion pressure (CPP = MAP - JVP) were less pronounced with propofol (P < 0.01 and P < 0.05, respectively). We conclude that propofol decreases CBFV and improves dynamic autoregulation during moderate hypothermic CPB. Furthermore, during propofol infusion, cerebral blood flow was in excess relative to oxygen demand, as indicated by the decrease in COE. ⋯ In this study, we evaluated the effects of propofol on continuously measured cerebral blood flow velocity (CBFV) and cerebral oxygen extraction as a function of perfusion pressure. Propofol induced 35% and 10% decreases in CBFV and cerebral oxygen extraction, respectively. The slope of the curve relating cerebral perfusion pressure to CBFV decreased with propofol.
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Anesthesia and analgesia · Jun 1998
Editorial CommentPatient simulator competency testing: ready for takeoff?
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Clinical TrialConjugated estrogen reduces transfusion and coagulation factor requirements in orthotopic liver transplantation.
We conducted a prospective, randomized study to determine the efficacy of conjugated estrogen in reducing blood product transfusion during orthotopic liver transplantation (OLT). Patients undergoing OLT were included in the study. Only those having a reaction time of more than 30 mm or 15 min (19 -28 mm) on computed thromboelastography (CTEG) at the beginning of surgery were enrolled in the study. Patients were randomized to receive either conjugated estrogen (CE) or placebo. Every patient received a first dose of CE (100 mg i.v.) (20 mL) or placebo (20 mL of isotonic sodium chloride solution) at the beginning of the procedure and a second dose of CE (100 mg i.v.) or 20 mL of placebo (20 mL of isotonic sodium chloride solution) just after reperfusion of the new graft. The two groups were similar in age, weight, requirement for veno-veno bypass, time on veno-veno bypass, CTEG measurement, and preoperative hemoglobin and platelet values. Blood products were given in relation to hematocrit and coagulation (CTEG) variables, which were measured every hour during the surgery. The amount of transfused blood products did not differ in terms of units of cryoprecipitate, but the intraoperative requirements for red blood cells (6 +/- 3 vs 9 +/- 6 U; P = 0.05), platelets (12 +/- 8 U vs 18 +/- 10 U; P = 0.05) and fresh-frozen plasma (3 +/- 3 U vs 6 +/- 4 U; P = 0.001) was significantly less in the estrogen group than in the control group. We conclude that CE is associated with a significant decrease in use of fresh-frozen plasma, platelets, and red blood cells during OLT. ⋯ In this study, we prospectively investigated whether i.v. conjugated estrogen could decrease blood product transfusion during orthotopic liver transplantation. Conjugated estrogen-treated patients received less fresh-frozen plasma, red blood cells, and platelets. In this population of patients, conjugated estrogen can be a useful addition in coagulation management during orthotopic liver transplantation.