Anesthesia and analgesia
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Anesthesia and analgesia · Apr 1996
Lidocaine inhibits blood coagulation: implications for epidural blood patch.
Lidocaine in the epidural space, through inhibitory effects upon coagulation, may contribute to inefficacy of epidural autologous blood patch (EBP). This study was undertaken to evaluate the effect of achievable epidural concentrations of lidocaine on blood coagulation as a step in testing this hypothesis. Ex vivo blood coagulation using whole blood (n = 20) was studied with computerized thrombelastography (TEG). ⋯ Statistical analysis using analysis of variance for repeated measures revealed that the three highest lidocaine concentrations tested caused hypocoagulable and/or fibrinolytic changes as compared with controls. Achievable epidural admixtures of lidocaine and whole blood will impair coagulation. Therefore, residual lidocaine in the epidural space may contribute to failures of immediate or early EBP.
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Anesthesia and analgesia · Apr 1996
The effects of propofol on hemodynamics and renal blood flow in healthy and in septic sheep, and combined with fentanyl in septic sheep.
Sepsis is characterized by myocardial depression and systemic vasodilation, both of which are most likely mediated by nitric oxide. Propofol inhibits nitric oxide synthase and may therefore be beneficial in sepsis. On the other hand, renal blood flow, known to be only minimally affected by propofol in healthy subjects, may be drastically reduced in septic individuals, because the renal microvasculature is known to be very sensitive to nitric oxide. ⋯ Renal blood flow was reduced to 60% +/- 10% of the preseptic baseline and to 39% +/- 4% of the septic value. This reduction was selective, since the cardiac output decreased significantly less. These adverse effects of propofol on hemodynamics and renal blood flow were reduced when propofol was combined with fentanyl.
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Anesthesia and analgesia · Apr 1996
Norepinephrine does not potentiate porcine malignant hyperthermia.
Malignant hyperthermia (MH) is a rare genetic trait characterized by potential life-threatening episodes of hypermetabolism, hyperthermia, and muscle rigidity when susceptible humans or animals are exposed to triggering drugs. The role of norepinephrine (NE) in triggering MH is controversial. The purpose of this study was to show that NE does not initiate nor speed the onset of MH in susceptible swine exposed to known triggering drugs. ⋯ The large dose NE infusion resulted in increased total catecholamines throughout the study in the NE group with no effect on time to MH trigger compared to animals where mean arterial pressure (MAP) was maintained by IABP. Animals in all three groups with times to trigger of less than 30 min had significantly higher MAPs at control, 15 min, and trigger time than those with times to trigger of greater than 30 min. We conclude that NE does not trigger MH and that severe reduction of MAP delays the the onset of MH in susceptible swine.
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Anesthesia and analgesia · Apr 1996
Postoperative analgesia with continuous epidural sufentanil and bupivacaine: a prospective study in 614 patients.
To assess the efficacy and safety of postoperative analgesia with continuous epidural sufentanil and bupivacaine, we performed a prospective study in 614 patients undergoing major surgery. Before surgical incision, all patients received an initial dose of 50 micrograms sufentanil in 6-10 mL bupivacaine 0.125% via a lumbar or thoracic catheter. After 1 h, a continuous infusion was started with 50 micrograms sufentanil in 50 mL bupivacaine 0.125% at a rate of 6-10 mL/h. ⋯ Late respiratory depression was observed in three patients; in most patients only minor side effects were seen. Technical complications during epidural puncture or insertion of the catheter were 4% and 3%, respectively. We conclude that continuous epidural sufentanil and bupivacaine is safe and effective.
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Anesthesia and analgesia · Apr 1996
The effects of sevoflurane, isoflurane, halothane, and enflurane on hemodynamic responses during an inhaled induction of anesthesia via a mask in humans.
A rapid increase in isoflurane or desflurane concentration induces tachycardia and hypertension and increases-plasma catecholamine concentration. Little information is available as to whether sevoflurane, halothane, and enflurane induce similar responses during anesthesia induction via mask. Fifty ASA physical status I patients, aged 20-40 yr, and scheduled for elective minor surgery, received one of four volatile anesthetics: sevoflurane, isoflurane, halothane, or enflurane. ⋯ In contrast, changes in sevoflurane and halothane concentrations did not induce hyperdynamic responses. Plasma norepinephrine concentration in the isoflurane group was significantly higher than that in the sevoflurane group during 2.7 MAC (P = 0.022). We propose that there is a direct relationship between airway irritation of the anesthetic and immediate cardiovascular change during an inhaled induction of anesthesia.