BACKGROUND: The required dose of anesthetics is generally smaller in patients with low cardiac output (CO). A high CO decreases the blood concentration of anesthetics during induction and maintenance of anesthesia. However, a high CO may also shorten the delivery time of anesthetics to the effect site, e.g. the brain. We assessed the time required for induction of anesthesia with propofol administered by target-controlled infusion (TCI), and investigated factors that modify the pharmacodynamics of propofol. METHODS: After measuring CO and blood volume (BV) by dye densitometry, propofol was infused using TCI to simulate a plasma concentration of 3 microg/ml. After infusion, the time taken to achieve bispectral index (BIS) values of 80 and 60 was determined. Age, sex, lean body mass (LBM), and cardiovascular parameters were analyzed as independent variables. The dependent variables were the time taken to achieve each BIS value and the plasma concentration of propofol (Cp) 10 min after the commencement of infusion. RESULTS: Multiple regression analysis revealed that a high CO significantly reduced the time taken to reach the first end point (P = 0.020, R2 = 0.076). Age and LBM significantly prolonged the time taken to reach the second end point (P = 0.001). Cp was negatively correlated with BV (P = 0.020, R2 = 0.073). CONCLUSIONS: Cardiac output was a statistically significant factor for predicting the time required for induction of anesthesia in the initial phase, whereas, age and LBM were significant variables in the late phase. The pharmacodynamics of propofol was intricately altered by CO, age, and LBM.
Anesthesia ; Anesthetics ; Blood Volume ; Brain ; Cardiac Output ; Cardiac Output, Low ; Consciousness Monitors ; Densitometry ; Humans ; Plasma ; Propofol

No abstract available.
Animals ; Mice

BACKGROUND: We hypothesized that cross-clamping of the descending thoracic aorta (CcDTA) would result in significant changes in plasma propofol concentrations (Cp) proximal and distal to the cross-clamp. We investigated the effect of CcDTA on Cp centrally and distally, including the pulmonary artery and the cardiopulmonary bypass (CPB) cannula. METHODS: The bispectral index (BIS) was recorded during CcDTA in eight patients undergoing thoracic aortic surgery using target-controlled total intravenous anesthesia with propofol. The calculated Cp was maintained at 3 microg/ml. Cp was measured in blood samples drawn from the right radial artery, left dorsalis pedis artery, pulmonary artery, and the long venous CPB cannula. RESULTS: Complete data were obtained from six patients. BIS decreased significantly in all cases 5 minutes after initiating CcDTA. BIS continued to decrease in association with increasing propofol concentrations. During CcDTA, Cp in samples from the radial and pulmonary arteries (3.5 +/- 0.50 and 2.9 +/- 0.63 microg/ml, mean +/- SD) was significantly higher than in samples from the dorsalis pedis artery and the venous cannula (1.1 +/- 0.22 and 1.4 +/- 0.02 microg/ml) (P < 0.05). CONCLUSIONS: The results suggest that almost all of the blood returning from the superior vena cava during CcDTA directly enters the pulmonary circulation without mixing with blood from the inferior vena cava. Observed changes in anesthetic blood concentrations could be due to the presence of a split circulation and asymmetrical distribution of propofol induced by CcDTA and CPB.
Anesthesia, Intravenous ; Aorta, Thoracic ; Arteries ; Cardiopulmonary Bypass ; Catheters ; Humans ; Plasma ; Propofol ; Pulmonary Artery ; Pulmonary Circulation ; Radial Artery ; Vena Cava, Inferior ; Vena Cava, Superior

BACKGROUND: Neonatal exposure to anesthetics induces neuronal apoptosis and long-term cognitive dysfunction in rodents. We showed that the nicotinamide adenine dinucleotide phosphate-oxidase inhibitor apocynin not only reduces neurotoxicity by decreasing superoxide levels and preventing mitochondrial dysfunction but also improves long-term memory impairment in neonatal mice exposed to sevoflurane. We also found that after the contextual fear conditioning test, glutamatergic neurons expressed c-Fos (neural activation) regardless of previous exposure to sevoflurane. Moreover, there were fewer c-Fos-expressing glutamatergic neurons in the basolateral amygdala (BLA) after exposure to sevoflurane than after exposure to carrier gas. In this study, we investigated whether the administration of apocynin prior to sevoflurane exposure would preserve glutamatergic neurons in the BLA. METHODS: Apocynin (50 mg/kg) was injected intraperitoneally into six-day-old male mice 30 min before 6 h of exposure to 3% sevoflurane or carrier gas only. The mice were allowed to mature and then were subjected to the contextual fear conditioning test. The neural activation and neuron population in the BLA were investigated 2 h later. RESULTS: Administration of apocynin prior to neonatal sevoflurane exposure not only prevented learning deficits but also preserved c-Fos-expressing glutamatergic neurons in the BLA. CONCLUSIONS: Apocynin mitigates the cognitive impairment induced by neonatal sevoflurane exposure and preserves c-Fos-expressing glutamatergic neurons in the basolateral amygdala.
Anesthesia ; Anesthetics ; Animals ; Apoptosis ; Basolateral Nuclear Complex* ; Brain ; Cognition Disorders ; Humans ; Learning ; Male ; Memory, Long-Term ; Mice* ; NAD ; Neurons* ; Pediatrics ; Rodentia ; Superoxides

BACKGROUND: Droperidol (DHB) reportedly reduces the dose of propofol needed to achieve hypnosis when anesthesia is induced and decreases the bispectral index (BIS) in propofol-sedated patients during spinal anesthesia. We reported previously that supplemental DHB decreased the BIS after the administration of sevoflurane and remifentanil. This study investigated the effect of DHB on desflurane (DES) consumption in a clinical setting. METHODS: We conducted a prospective, randomized double-blinded study of 35 women with American Society of Anesthesiologist physical status I or II who underwent a mastectomy. Either DHB (20 µg/kg) or a saline placebo was administered to patients 30 min after the induction of anesthesia. A blinded anesthesiologist maintained a BIS value of 50 during anesthesia by modulating inhaled DES concentrations that changed 0.5% at 2.5 min intervals and maintained analgesia via the constant administration of remifentanil by referring to vital signs. The primary endpoint was the effect of DHB on DES consumption. The secondary endpoints included blood circulatory parameters, the time from the end of surgery to extubation, and discharge time between the groups. RESULTS: The characteristics of the patients did not differ between the groups. The DHB group used a mean of 27.2 ± 6.0 ml of DES compared with 41.4 ± 9.5 ml by the placebo group (P < 0.05). CONCLUSIONS: A small dose of DHB reduced the DES concentration needed to maintain a BIS of 50. Our results show that DHB reduced the consumption of DES without adverse effects.
Analgesia ; Anesthesia ; Anesthesia, General ; Anesthesia, Spinal ; Breast Neoplasms* ; Breast* ; Droperidol* ; Female ; Humans ; Hypnosis ; Mastectomy ; Propofol ; Prospective Studies ; Vital Signs