ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

To determine whether the caloric source of intravenous nutrition can influence oxidative drug metabolizing capacity, antipyrine metabolism was studied in six healthy volunteers, who were taking no food or liquid by mouth, after they had been administered an intravenous nutritional regimen of 5% dextrose, 440 kcal/day, for 4 days and after they had been switched to an essentially isocaloric intravenous nutritional regimen of amino acids (Aminosyn® 3.5%) for 1 day. The change in intravenous nutritional regimen resulted in a 21% decrease in mean half-life (range: 3–32%), a 20% decrease in mean area under the concentration-time curve (range: 4–42%), and a 24% increase in mean metabolic clearance rate (range: 2–71%) for antipyrine. These results show that the change from intravenous dextrose to intravenous amino acids for only 1 day produced in all subjects an increase in antipyrine metabolism. Interestingly, there was marked variability in the responsiveness of the different subjects to the change in intravenous caloric source.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Morphine, 20 mg·kg−1, sc, halved the plasma clearance of sulfobromophthalein (BSP) while tripling hepatic tissue levels of this dye. Since narcotics depress respiration, effects of hypoxia, hypercapnia, and acidosis on BSP disposition were studied. Ambient gases breathed by rats were adjusted to achieve blood gas levels identical to those of morphine-induced respiratory depression. Saline-treated rats breathing room air had PAo2of 87 ± 3 mmHg (mean ± SE) and Paco2of 40 ± 2 mmHg. After intraarterial injection of BSP, 100mg·kg−1, plasma clearance of this dye was 7.1 ± 1.1 ml·min−1and BSP levels in the liver at 40 min after injection were 163.3 ± 19.8 μg· kg−1. After morphine, 20 mg·kg−1, Pao2decreased to 47 ± 4 mmHg and Paco2increased to 89 ± 5 mmHg. In these rats BSP clearance dropped to 3.5 ± 0.4 ml·min−1, and 40-min liver dye levels were increased to 596.4 ± 60.4 μg·g−1. Similar hypoxia and hypercapnia caused by breathing 9% O2and 8% CO2in the absence of morphine caused plasma BSP clearance to be decreased to 4.4 ± 0.2 ml·min−1and 40-min hepatic BSP to be increased to 292.5 ± 31.8 μg·g−1. Hypercapnia and acidosis alone did not affect BSP disposition, while hypoxia without hypercapnia decreased its plasma clearance to 5.5 ± 0.3 ml·min−1and increased liver levels to 339.1 ± 35.1 μg·g−1. Hypoxia was reversed completely in morphine-treated rats by placing them in 40% O2. In these animals, despite normal oxygen, plasma BSP clearance was decreased to 4.4 ± 0.6 ml·min−1, and liver BSP was increased to 497.9 ± 65.6 μg·g−1. Thus, respiratory depression with hypoxia may contribute to morphine-induced effects on BSP disposition, but altered blood gases cannot account fully for these narcotic effects.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The systemic and cerebral effects of hypotension induced with isoflurane were examined in 12 dogs. Hypotension to a mean arterial pressure of either 50 mmHg or 40 mmHg for 1 h was produced by 2.5 ± 0.1–2.9 ± 0.3% end-expired isoflurane anesthesia. Before and during the period of hypotension the following were measured or derived: arterial and pulmonary artery pressures; arterial, mixed venous, and sagittal sinus blood gases; cardiac output and cerebral blood flow; whole body and cerebral oxygen consumption; systemic and cerebral vascular resistance; intracranial pressure, serum lactate, and pyruvate concentrations; and blood glucose. At the end of the period of hypotension, brain biopsy specimens were taken for the determination of ATP, ADP, AMP, phosphocreatine, lactate, and pyruvate concentrations.Isoflurane-induced hypotension produced a significant decrease in systemic vascular resistance (27–43%) associated with a significant decrease in cardiac output (39–42%) and a smaller decrease in whole-body oxygen consumption (14–21%). Isoflurane also produced a significant decrease in cerebral oxygen consumption (40–44%) accompanied by a decrease in cerebral blood flow (60–62%). Following both the 40 and 50 mmHg periods of hypotension, the cerebral energy state was normal, indicating the preservation of normal aerobic metabolism. This differs from previous results obtained using a similar protocol, wherein trimethaphan-induced hypotension to 50 mmHg and trimethaphan, halothane, and nitroprusside-induced hypotension to 40 mmHg were associated with gross alterations in the cerebral energy state. Our failure to observe any detrimental effects of isoflurane-induced hypotension indicates that isoflurane may offer some advantage over other hypotensive techniques and is consistent with the concept that isoflurane offers a potential for cerebral protection.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Central and splanchnic hemodynamic effects during controlled hypotension induced by the administration of the endogenous vasodilator adenosine were studied in ten artificially ventilated dogs under neurolept anesthesia. Adenosine was administered as a continuous infusion in the aorta (n = 3), in the inferior vena cava (n = 3), and after pretreatment with dipyridamole (which inhibits the cellular uptake of adenosine) (n = 4) in a dose sufficient to maintain a mean arterial blood pressure (MABP) level of approximately 50 mmHg. Observations were made before and after 20 min of controlled hypotension. Basal arterial plasma levels of adenosine were in the 10−7M range (&OV0398; = 0.4 μM). The hemodynamic response was similar in all three settings. Adenosine caused a profound decrease in systemic vascular resistance (SVR) (52%,P< 0.01) and preportal vascular resistance (PPR) (64%,P< 0.01), while hepatic arterial vascular resistance (HAR) increased by 49% (P< 0.05). Cardiac output increased (22%,P< 0.05) through increase of stroke volume (77%,P< 0.01), while heart rate decreased (28%,P< 0.01). Whole-body oxygen uptake decreased (14%,P< 0.01). Portal venous blood flow increased by 28% (P< 0.05), whereas hepatic arterial blood flow decreased by 70% (P< 0.01). In the preportal tissues, oxygen uptake decreased by 21% (P< 0.01). In contrast, hepatic oxygen consumption increased (53%,P< 0.05). Adenosine-induced hypotension was not associated with changes in plasma renin activity or the plasma concentration of norepinephrine. It is concluded that adenosine causes a rapidly induced and easily maintained hypotension and may be a potentially useful agent for controlled hypotension in patients.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The effects of morphine, halothane, and their various combinations on the purposeful movement (PM) response and the heart rate (HR) increase caused by noxious stimulation were studied in 250 rat experiments. Doses that block the PM and HR responses for the single agent and for combinations were determined with a probit procedure and compared with an isobolographic analysis. As was evidenced by the PM response, the combined anesthetic effect of morphine and halothane, with some deviations, may be defined as additive. It also was found that the combined administration of morphine and halothane results in an antagonism for suppression of the HR increase to noxious stimulation. Halothane antagonized morphine to a much greater extent than morphine to halothane.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The stability of the pulmonary blood pressure and flow response to alveolar hypoxia (hypoxic pulmonary vasoconstriction or HPV) was studied in six pentobarbital anesthetized, mechanically ventilated open-chested dogs. Aortic and left pulmonary artery blood flows; systemic and pulmonary arterial, central venous, left atrial, and airway pressures; hemoglobin; arterial and mixed venous blood gases were measured. The right lung was ventilated continuously with 100% oxygen, while the left lung was ventilated alternately with 100% O2(prehypoxia control phase), an hypoxic gas mixture containing 4% O2, 3% CO2, balance N2for 4 h, or 100% O2(post-hypoxia control phase). Hypoxic ventilation of the left lung resulted in an immediate and sustained decrease in left lung blood flow (&OV0422;L%) from 39.0 ± 1.8% (mean ± SE) to 9.9 ± 3.6% at 15 min of hypoxic ventilation. &OV0422;L% remained decreased and did not vary significantly during the 4 h of hypoxia. Venous admixture correspondingly was increased and Pao2decreased by hypoxic ventilation and did not vary significantly during the 4 h of hypoxia. All variables returned to control levels upon reestablishing ventilation with 100% O2.While the maximal reduction in &OV0422;L% with left lung hypoxic ventilation was identical to that observed during atelectasis previously in our laboratory, the time course of the response was different. The response to hypoxia was maximal by 15 min, however, &OV0422;L% decreased more slowly during atelectasis, where the maximal reduction was observed by 60 min. The present study therefore demonstrated that hypoxic ventilation of the left lung yielded an immediate and sustained decrease in left lung blood flow for 4 h. The stability of the HPV response probably was accounted for by the lack of such confounding factors as respiratory alkalosis, severe systemic hypoxemia, and increased cardiac output.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The effect of nitrous oxide on the elimination of halothane was studied in 10 patients ranging in age from 20 to 50 years. After establishing a stable baseline (inspired halothane concentration: 0.85%, end-tidal halothane concentration: 0.75%), halothane administration was stopped and the rate of decrease in alveolar concentration of halothane (FE/FE0FE: measured end-tidal concentration of halothane; FE0: the endtidal concentration immediately preceding the cessation of halothane administration) was measured continuously. The rate of decrease in FE/F0was more rapid when nitrous oxide (70%) is discontinued abruptly and replaced by the same concentration of nitrogen (Part 2) than when the nitrous oxide is continued (Part 1). One minute and a half after the cessation of halothane administration, FE/FE0, was 0.38 ± 0.05 (mean ± SD) in Part 2 and 0.45 ± 0.04 in Part 1 (P< 0.01). In Part 2, the fall in the alveolar concentration of halothane was accompanied by a decrease in alveolar carbon dioxide from 4.27 ± 0.01% to 4.16 ± 0.01 % at 1.5 min and an increase in the mean expired tidal volume from 522 ± 39 ml to 557 ± 29 ml. The authors conclude that the elimination of nitrous oxide accelerates the elimination of halothane both by dilution and by an increased expired ventilation.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Vecuronium and pancuronium were compared for placental transfer, pharmacokinetic variables, and neonatal effects during cesarean section under general anesthesia. Eighteen women underwent rapid-sequence intravenous induction usingd-tubocurarine, succinylcholine, thiopental, and oxygen. Immediately after tracheal intubation, an intravenous injection of vecuronium (n = 11) or pancuronium (n = 7), 0.04 mg/kg, was given. Maternal venous blood samples were obtained before induction and at frequent intervals for 4 h after administration of vecuronium or pancuronium. Also, maternal venous and umbilical-cord arterial and venous blood samples were obtained at delivery. To describe placental transfer and maternal pharmacokinetics of the drugs, serum drug concentrations were determined using single-ion-monitoring mass spectrometry. The Apgar score and Neurologic and Adaptive Capacity Score (NACS) were used to evaluate neonatal condition. Both drugs crossed the placenta, as demonstrated by low concentrations of vecuronium (8.5–26.4 ng/ml) or pancuronium (12.2–34.2 ng/ml) found in umbilical venous blood. At delivery, the ratio of the drug concentration in umbilical venous blood to that in maternal venous blood was 0.11 ± 0.02 for vecuronium and 0.19 ± 0.03 for pancuronium. Vecuronium had a more rapid clearance (6.4 ± 0.4 ml±kg−1± min−1, mean ± SE) and a shorter elimination half-life (36 ± 1.8 min) than pancuronium (3.0 ± 0.1 ml·kg−1· min−1and 72 ± 6 min, respectively). No other pharmacokinetic differences were found between the drugs. Neonatal outcome was not affected adversely by either muscle relaxant, as assessed by Apgar scores and NACSs. The short duration of action, the minimal placental transfer, and the apparent lack of clinical neuromuscular effects on the newborn suggest that vecuronium should be a useful muscle relaxant for cesarean section.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Cerebral blood volume (CBV) and intracranial (ICP) were examined in dogs during 3.5 h anesthesia with isoflurane (1.4% expired) or fentanyl (continuous intravenous infusion), and after decreasing the concentration of isoflurane to <0.15% expired or discontinuing administration of fentanyl. Isoflurane (1.4%) increased CBV 9–11 % for >3 h but increased ICP for only the first 21.7 ± 1.4 min (mean ± SEM). Fentanyl decreased CBV 7–10% for >3 h but decreased ICP for only the first 20.3 ± 2.7 min. Because both halothane or enflurane increase ICP for <3 h in this model, both isoflurane or fentanyl may be preferred to halothane or enflurane for patients at risk for increased ICP.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID