Anesthesia and analgesia
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Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Comparative Study Clinical TrialPreoperative acute hypervolemic hemodilution with hydroxyethylstarch: an alternative to acute normovolemic hemodilution?
Acute normovolemic hemodilution (ANH) may help to reduce demand for homologous blood but requires extra time and apparatus. A more simple procedure is acute hypervolemic hemodilution (HHD), where hydroxyethylstarch is administered preoperatively without removal of blood. In a prospectively randomized study we compared ANH (preoperatively 15 mL/kg autologous blood removal and replacement with 15 mL/kg of hydroxyethylstarch with HHD (15 mL/kg of hydroxyethylstarch administered preoperatively) in 49 patients undergoing hip arthroplasty. ⋯ Mean time required to perform ANH was 58 (46-62) min versus HHD 16 (12-19) min (P < 0.05). Costs for ANH were $63.60 USD and for HHD $32.75 USD (labor costs not included). In orthopedic patients undergoing hip replacement with a predicted blood loss of about 1000 mL, HHD seems to be a simple as well as time- and cost-saving alternative for ANH.
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Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialThe effects of reversal of neuromuscular blockade on autonomic control in the perioperative period.
Impaired parasympathetic control of heart rate is associated with increased incidence of cardiac dysrhythmias and ischemia. Anticholinergic drugs suppress parasympathetic control and could be detrimental in the early postoperative period in high-risk patients. In this double-blind randomized trial, 30 ASA physical status I and II patients undergoing minor surgery received either atropine 20 micrograms/kg and neostigmine 50 micrograms/kg (Group A), glycopyrrolate 8 micrograms/kg and neostigmine 50 micrograms/kg (Group G), or placebo (Group P) for reversal of neuromuscular blockade. ⋯ Groups A and G showed a borderline decrease in normalized high-frequency variability at 2 h (P = 0.05 for Groups A and G versus Group P). Anticholinergic drugs with neostigmine cause impairment of parasympathetic control of heart rate which persists into the early postoperative period. The effects of glycopyrrolate appear to be of shorter duration; this drug may thus be preferable in patients at risk of cardiovascular complications.
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Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Comparative Study Clinical TrialPrevention of hypotension during spinal anesthesia: a comparison of intravascular administration of hetastarch versus lactated Ringer's solution.
This study was designed to compare the efficacy of 6% hetastarch to that of crystalloid administration in reducing the incidence and severity of hypotension during spinal anesthesia. Forty ASA grade I patients scheduled for postpartum tubal ligations under spinal anesthesia were randomly allocated to receive either 500 mL of hetastarch solution or 1000 mL of lactated Ringer's solution prior to spinal anesthesia. Spinal anesthesia was managed identically in both groups by anesthesiologists who were unaware of the type of fluid administered. ⋯ The difference in the incidence of hypotension was significant (P < 0.05). The requirement of 5-mg bolus doses of ephedrine to maintain systolic arterial blood pressure > 75% of baseline was significantly greater in the lactated Ringer's group than in the hetastarch group (15 vs 4, P < 0.05). We conclude that an intravenous infusion of 500 mL of 6% hetastarch solution is more effective than 1000 mL lactated Ringer's solution in attenuating spinal anesthesia induced hypotension in women undergoing postpartum tubal ligation.
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Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialHemodynamic effects, myocardial ischemia, and timing of tracheal extubation with propofol-based anesthesia for cardiac surgery.
Recent interest in earlier tracheal extubation after coronary artery bypass graft (CABG) surgery has focused attention on the potential benefits of a propofol-based technique. We randomized 124 patients (34 with poor ventricular function) undergoing CABG surgery to receive either a propofol-based (5 mg.kg-1.h-1 prior to sternotomy, 3 mg.kg-1. h-1 thereafter; n = 58) or enflurane-based (0.2%-1.0%, n = 66) anesthetic. Induction of anesthesia consisted of fentanyl 15 micrograms/kg and midazolam 0.05 mg/kg intravenously in both groups. ⋯ Patients receiving propofol were extubated earlier (median 9.1 h versus 12.3 h, P = 0.006), although there was no difference in time to intensive care unit (ICU) discharge (both 22 h, P = 0.54). Both groups had similar hemodynamic changes throughout (all P > 0.10), as well as metaraminol (P = 0.49) and inotrope requirements (P > 0.10), intraoperative myocardial ischemia (P = 0.12) and perioperative myocardial infarction (P = 0.50). The results of this trial suggest that a propofol-based anesthetic, when compared to an enflurane-based anesthetic requiring additional dosing of fentanyl and midazolam for CPB, can lead to a significant reduction in time to extubation after CABG surgery, without adverse hemodynamic effects, increased risk of myocardial ischemia or infarction.
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Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialThe duration of impairment of autonomic control after anticholinergic drug administration in humans.
Impaired parasympathetic control of heart rate is associated with increased incidence of cardiac dysrhythmias and ischemia. Anticholinergic drugs, commonly administered during reversal of neuromuscular blockade, suppress parasympathetic control in the early postoperative period. This could potentially be detrimental in patients at risk of cardiovascular complications. ⋯ Both drugs resulted in a marked decrease in baroreflex sensitivity and high-frequency heart rate variability. The times to return to baseline values were approximately doubled after atropine compared to glycopyrrolate (177 +/- 22 vs 82 +/- 8 min for baroreflex sensitivity, 212 +/- 16 vs 111 +/- 14 min for high-frequency power, and 171 +/- 18 vs 95 +/- 18 min for high-frequency power normalized to total power; P < 0.01 for all variables). Atropine leads to more prolonged impairment of parasympathetic control than equipotent doses of glycopyrrolate, and its use may thus be less desirable in high-risk patients in the early postoperative period.