Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1980
Tachyphylaxis and phase II block development during infusion of succinylcholine in children.
Contraction of the adductor of the thumb in response to ulnar nerve stimulation during continuous infusion of succinylcholine (SCh) was evaluated in 22 children anesthetized with halothane (1% to 1.5%) and N2O/O2. Twitch rates of 0.1 Hz were used to evaluate the force of contraction. Train-of-four stimulation (2 Hz for 2 seconds) was used to differentiate between phase I and phase II block. ⋯ A mean dose of 10.3 +/- 0.6 mg/kg of SCh administered in a span of 71 +/- 5 minutes produced a mean train-of-four ratio of 12 +/- 5%. The recovery from phase II block after 10.3 +/- 0.6 mg/kg of SCh to train-of-four ratios of 50% and 75% was 16 +/- 3 minutes and 41 +/- 5 minutes, respectively. Caution should be used when more than 3 mg/kg of SCh is infused intravenously; adequate neuromuscular monitoring should be available and ample time should be given for spontaneous recovery.
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Experiments were performed in a rat sciatic nerve preparation to determine the characteristics of nerve blocks produced by a combination of commercially available solutions of bupivacaine and chloroprocaine. A mixture of equal parts of commercially available chloroprocaine 2% and bupivacaine 0.5% resulted in a nerve blockade with characteristics of a chloroprocaine block. Changing the pH value of this mixture from 3.60 to 5.56 changed these characteristics to a blockade resembling that produced by bupivacaine. It is concluded that the nerve blockades obtained by mixing commercially available solutions of local anesthetics are unpredictable and may depend on a number of factors which include not only the types of drugs but the pH of the mixture.
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Anesthesia and analgesia · Sep 1980
Halothane-induced suppression of cell-mediated immunity in normal and tumor-bearing C3Hf/He mice.
The present investigation was designed to demonstrate whether depression of cell-mediated immunity in tumor-bearing hosts is potentiated by halothane anesthesia. Both the in vivo and in vitro effects of halothane anesthesia on splenic lymphocytes from normal and tumor-bearing C3Hf/He mice were examined by lymphocyte transformation. The stimulation index (SI) of lymphocytes from normal C3Hf/He mice exposed to 1.5% halothane/98.5% oxygen anesthesia was significantly less than that of lymphocytes from normal C23Hf/He mice exposed to oxygen (SI of 25.3 and 33.6, respectively) (p < 0.001). ⋯ Lymphocytes from tumor-bearing hosts exposed to 1.5% halothane anesthesia demonstrated diminished lymphocyte transformation compared with those from control (tumor-bearing) mice exposed to oxygen (SI of 1.7 and 4.4, respectively) (p < 0.001). In both tumor-bearing and normal mice, there was a significant suppression of the cell-mediated immune response when the animals were exposed to halothane compared to exposure to oxygen. Results of this investigation demonstrate that halothane anesthesia potentiates the suppression of cell-mediated immunity observed in tumor-bearing hosts.