Anesthesia and analgesia
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Anesthesia and analgesia · Dec 1999
Comment Letter Comparative StudyThe difference between actual and calculated osmolality of IU solutions should not be overlooked.
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Anesthesia and analgesia · Dec 1999
Clinical TrialThe hemodynamic effects of propofol in children with congenital heart disease.
We studied the hemodynamic effects of propofol during elective cardiac catheterization in 30 children with congenital heart disease. Sixteen patients were without cardiac shunt (Group I), six had left-to-right cardiac shunt (Group II), and eight had right-to-left cardiac shunt (Group III). The mean (+/-SD) ages were 3.8+/-3.1 yr (Group I), 3.2+/-3.7 yr (Group II), and 1.0+/-0.6 yr (Group III). After sedation and cardiac catheter insertion, hemodynamic data and oxygen consumption were measured before and after the administration of propofol (2-mg/kg bolus, 50- to 200-microg x kg(-1) x min(-1) infusion), and values were compared by using a paired t-test (significance: P < 0.05). After the propofol administration, systemic mean arterial pressure and systemic vascular resistance decreased significantly and systemic blood flow increased significantly in all patient groups; heart rate, pulmonary mean arterial pressure, and pulmonary vascular resistance were unchanged. Pulmonary to systemic resistance ratio increased (Group I, P = 0.005; Group II, P = 0.03; Group III, P = 0.10). In patients with cardiac shunt, propofol resulted in decreased left-to-right flow and increased right-to-left flow; the pulmonary to systemic flow ratio decreased significantly (Group II, P = 0.005; Group III, P = 0.01). Clinically relevant decreases in Pao2 (P = 0.008) and Sao2 (P = 0.01) occurred in Group III patients. We conclude that propofol can result in clinically important changes in cardiac shunt direction and flow. ⋯ The principal hemodynamic effect of propofol in children with congenital heart defects is a decrease in systemic vascular resistance. In children with cardiac shunt, this results in a decrease in the ratio of pulmonary to systemic blood flow, and it can lead to arterial desaturation in patients with cyanotic heart disease.
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Anesthesia and analgesia · Dec 1999
Randomized Controlled Trial Clinical TrialThe failure of negative pressure rewarming (Thermostat) to accelerate recovery from mild hypothermia in postoperative surgical patients.
The Thermostat device (Aquarius Medical Corp., Phoenix, AZ) is used in a new technique to accelerate recovery from hypothermia by mechanically distending blood vessels in the hand, thereby increasing transfer of exogenous heat to the body core. We evaluated the use of the Thermostat device in patients with mild postoperative hypothermia (< 36 degrees C). We studied adult patients undergoing elective surgery, general anesthesia, and neuromuscular blockade. Patients with an initial postoperative tympanic membrane temperature < 36 degrees C were randomized into two groups: 1) Thermostat, which consisted of a hypothermia warming mitt/seal and thermal exchange chamber for 60 min, and 2) conventional treatment, which consisted of warm blankets and/or radiant heat. Of the 191 patients enrolled, 60 (31%) developed hypothermia and were randomized to receive the Thermostat (n = 30) or conventional methods (n = 30). Fourteen patients in the Thermostat group and 17 patients in the conventional group rewarmed to 36 degrees C before discharge from the recovery room (P is not significant). There were no differences in vital signs, rewarming time, time to discharge from the recovery room, or postoperative temperature between groups. We conclude that patients with mild postoperative hypothermia rewarmed in a similar fashion, regardless of whether the Thermostat or conventional methods were used. ⋯ We found that a commercially available negative pressure rewarming device (Thermostat; Aquarius Medical Corp., Phoenix, AZ) was not effective in accelerating rewarming in postoperative hypothermic surgical patients after general anesthesia.
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Anesthesia and analgesia · Dec 1999
Comparative Study Clinical TrialPreoperative anxiety and intraoperative anesthetic requirements.
The purpose of this study was to determine whether larger doses of anesthetics are required in the anxious patient to establish and maintain a clinically sufficient hypnotic component of the anesthetic state. Fifty-seven women undergoing bilateral laparoscopic tubal ligation with a propofol-based anesthetic regimen were enrolled in this cross-sectional study. Trait (baseline) and state (situational) anxiety were assessed in all patients immediately before surgery, and the propofol doses required for the induction and maintenance of anesthesia were recorded. A bispectral index monitor was used to assure that the hypnotic component of the anesthetic state was the same in all patients. We found that patients with high trait anxiety required more propofol for both the induction (2.1+/-0.4 vs 1.8+/-0.3 mg/kg; P = 0.01) and maintenance of anesthesia (170+/-70 vs 110+/-20 microg x kg(-1) x min(-1); P = 0.02), compared with patients with low trait anxiety. State anxiety, however, was not found to affect the propofol doses required for the induction or maintenance of anesthesia. Multiple regression models confirmed that Trait anxiety is an independent predictor for intraoperative propofol requirements (P = 0.02). We conclude that increased baseline (i.e., trait) anxiety is associated with increased intraoperative anesthetic requirements. Thus, we suggest that the initial dose of anesthetic administered by an anesthesiologist should be modified based on the anxiety level exhibited by the patient. ⋯ The goal of this study was to assess the relationship between preoperative anxiety and intraoperative anesthetic requirements. We found that high baseline anxiety predicts increased intraoperative anesthetic requirements. We suggest that anesthesiologists should modify the initial induction dose based on the anxiety level exhibited by the patient.
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Anesthesia and analgesia · Dec 1999
Effect of small-dose dopamine on mesenteric blood flow and renal function in a pig model of cardiopulmonary resuscitation with vasopressin.
Vasopressin (antidiuretic hormone) seems a promising alternative to epinephrine for cardiopulmonary resuscitation (CPR) in cardiac arrest victims, mediating a pronounced blood flow shift toward vital organs. We evaluated the effects of small-dose dopamine on splanchnic blood flow and renal function after successful resuscitation with this potent vasoconstrictor in an established porcine CPR model. After 4 min of cardiac arrest and 3 min of CPR, animals received 0.4 U/kg vasopressin and were continuously infused with either dopamine 4 microg x kg(-1) x min(-1) (n = 6), or saline placebo (n = 6). Defibrillation was performed 5 min after drug administration; all animals were observed for 6 h after return of spontaneous circulation. During the postresuscitation phase, average mean +/- SD superior mesenteric artery blood flow was significantly (P = 0.002) higher in the dopamine group compared with the placebo group (1185+/-130 vs 740+/-235 mL/min), whereas renal blood flow was comparable between groups (255+/-40 vs 250+/-85 mL/min). The median calculated glomerular filtration rate had higher values in the dopamine group (70-120 mL/min) than in the placebo group (40-70 mL/min; P = 0.1 at 0 min and P = 0.08 at 360 min). We conclude that small-dose dopamine administration may be useful in improving superior mesenteric artery blood flow and renal function after successful resuscitation with vasopressin. ⋯ Long-term survival after cardiac arrest may be determined by the ability to ensure adequate organ perfusion during cardiopulmonary resuscitation and in the postresuscitation phase. In this regard, small-dose dopamine improved postresuscitation blood flow to the mesenteric bed when vasopressin was used as an alternative vasopressor in an animal model of cardiac arrest.