Journal of anesthesia
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Journal of anesthesia · Dec 1995
RETRACTED ARTICLE: The dose-response relationship of amrinone in increasing the contractility of fatigued diaphragm in dogs.
We studied the dose-related effects of amrinone on the contractility of a fatigued diaphragm in 16 anesthetized, mechanically ventilated dogs. The animals were divided into two groups: the control group (Group C,n=8) and the amrinone group (Group A,n=8). Diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20 Hz applied for 30 min. ⋯ In Group, C, the speed of recovery ofP di at 20 Hz stimulation was relatively slower. The integrated electric activity of the diaphragam (E di) in each group did not change at any frequency of stimulation throughout the experiment. We conclude that amrinone exerts a dose-dependent enhancement of the contractility of a fatigued diaphragm in dogs.
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To reduce the doses of intravenous anesthetics (ketamine, diazepam, droperidol, and vecuronium) used in total intravenous anesthesia (TIVA), epidural administration of a ϰ-stimulating opioid, eptazocine, was combined with TIVA in 115 patients. Surgical procedures were uneventful under TIVA plus epidural eptazocine; significant depression of EEG and somatosensory-evoked potentials during anesthesia were observed without delay in recovery. ⋯ Therefore, epidural eptazocine may make it possible to use lower doses of anesthesia in TIVA, thus reducing the adverse effects associated with TIVA such as hypertension during surgery, intraoperative awareness, postanesthetic respiratory depression, delayed recovery from anesthesia, and neurological signs after anesthesia. This may be due to the ϰ-stimulating action of epidural eptazocine on the spinal cord and its σ-blocking action, as well as its lack of μ-action on the brain.
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Journal of anesthesia · Dec 1995
Evaluation of a delivery system and monitors for ventilator administration of nitric oxide.
The aim of this study was to compare nitric oxide (NO) and nitrogen dioxide (NO2) measurements obtained by chemiluminescence and electrochemical monitors using a delivery system for ventilator administration of NO. The formation of NO2 in this system and the efficacy of a soda-lime absorber to scavenge NO2 from inspiratory gas were also evaluated. Various concentrations of NO without and with soda lime were administered to a model lung via a Servo ventilator 900C with controlled ventilation by setting mass-flow regulators to maintain desired concentrations of NO in 80% O2. ⋯ NO, although a high concentration of NO2 appeared in the breathing circuit without soda lime. Four hundred grams of soda lime continued to absorb NO2 effectively during long-term administration of inhaled NO. These findings suggest that electrochemical monitoring is accurate and clinically useful for measurements of NO and NO2 concentrations, and that low doses of inhaled NO can be administered safely and reliably with the NO delivery system using a soda-lime absorber and mass-flow regulators.
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Journal of anesthesia · Dec 1995
Difference of train-of-four fade induced by nondepolarizing neuromuscular blocking drugs: a theoretical consideration on the underlying mechanisms.
Nondepolarizing neuromuscular blocking drugs induce train-of-four (TOF) fade, i.e., the reduction of the fourth to the first twitch height in a train under TOF stimulation. It has been observed that the degree of TOF fade varies with the drug used and is inversely correlated with the potencies of the drug. ⋯ The model was based on the following assumptions: (1) Twitch response is evoked by the binding of acetylcholine (ACh) molecules to the postsynaptic nicotinic receptors in a neuromuscular junction, (2) time-dependent ACh mobilization in a motor nerve terminal results in less ACh output at the fourth stimulus in a train than at the first stimulus, (3) the drugs compete with ACh for the postsynaptic receptors and inhibit the receptor-binding of ACh, and (4) the drugs have various affinities for the receptors. This study suggested that the difference of affinities of the drugs for postsynaptic ACh receptors may cause the difference of TOF fade.
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Journal of anesthesia · Dec 1995
Effects of stellate ganglion block on cardiac coronary circulation.
Since the stellate ganglion contains cardiac sympathetic nerves, stellate ganglion block (SGB) may influence cardiac and coronary hemodynamics. We investigated this influence of SGB by measuring the heart rate (HR), the left circumflex coronary artery blood flow (CBF), the maximum rate of increase of the left ventricular pressure (LV max dP/dt), the cardiac output (CO), the myocardial oxygen consumption (MVO2), and the myocardial oxygen extraction ratio (MOER) in nine dogs before and after performing SGB by means of injection of 2 ml 1% mepivacaine. Left SGB resulted in a decrease of 10% in CBF and a decrease of 15% in LV max dP/dt, but HR, CO, and MVO2 remained unchanged. ⋯ Inhalation of 100% oxygen decreased MOER to the pre-SGB level in either side, thus improving the myocardial oxygen supply-demand relationship. This study suggests the possibility that SGB has deteriorative effects on the myocardial oxygen supply-demand relationship. Those effects were counteracted by the inhalation of 100% oxygen.