ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

While it is generally agreed that cerebral blood flow (CBF) increases during hypercarbia, measurements of cerebral metabolic rate (CMRO2) during hypercarbia have yielded divergent results. Accordingly, the authors reexamined the changes in CMRO2during normocarbia and hypercarbia to 80 and 100 torr employing a canine model designed to minimize potential measurement errors introduced by hypercarbia. Repetitive measurements of arterial–cerebral venous blood oxygen content differences C(a-v)O2were made, and CBF was measured simultaneously by both a direct (sagittal sinus blood flow collection) and an indirect (133Xe washout) technique. CMRO2, derived from the direct CBF measurements and C(a-v)O2, was unchanged at PaO2, 80 torr and was significantly decreased (by 10 per cent) at PaCO2100 torr. Comparison of the two techniques for determining CBF showed good agreement between the direct method and fast compartment analysis of the133Xe washout.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Hepatic centrilobular necrosis developed in rats pretreated with triiodothyronine (T3) and then anesthetized with halothane, 1 per cent, for two hours at an ambient oxygen concentration. Increasing oxygen concentrations decreased the severity of the lesion, there being a significantly (P< 0.05) less severe lesion with oxygen, 99 per cent, as compared with 21 per cent. Pretreatment with phenobarbital alone resulted in hepatic necrosis only when hypoxia (F1O20.14) was also present, and there was no significant worsening of the T3-induced lesion when phenobarbital was added at any oxygen concentration studied. However, the lesion produced by T3and oxygen, 14 per cent, was significantly worse than the lesion produced by phenobarbital and oxygen, 14 per cent. Glutamic pyruvic transaminase (SGPT) was significantly elevated to 776 (±226) U/I in the T3-treated rats (10 mg/kg/day, orally) immediately after halothane anesthesia. There was a significant decrease in glutathione to 1.48 (±0.06) mg/g liver 24 hours after T3administration (1 mg/kg subcutaneously for five days), but no further decrease with continued T3pretreatment or with halothane anesthesia. Pretreatment with T3caused a significant decrease in cytochrome P-450 to 0.41 (±0.01) nmol/mg microsomal protein, and halothane anesthesia caused a further significant decrease to 0.27 (±0.04) nmol/mg microsomal protein. The mechanism for the hepatic toxicity of halothane in this model remains to be determined.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

To assess the change in venous admixture during breathing of 100 per cent oxygen (F1O2, 1.0), shunt fraction (Qs/Qt) was calculated at a maintenance F1O2(F1O2m: 0.27–0.70) and at F1O21.0 in 40 studies of 34 patients with acute respiratory failure. At F1O21.0 Qs/Qtincreased in 26 studies, but did not increase in 14 studies. Patients in whom Qs/Qtincreased during breathing of oxygen had mild respiratory failure, as indicated by low Qs/Qtvalues at F1O2mand a low incidence of diffuse parenchymal infiltrates on chest roentgenograms. All patients who had recently had cardiovascular surgical procedures were in this group. Respiratory failure was more severe in those in whom Qs/Qtdecreased with oxygen, as indicated by high Qs/Qtvalues at F1O2mevidence of diffuse pulmonary disease by roentgenography, and signs of adult respiratory distress syndrome. The authors conclude that changes in Qs/Qtin response to F1O21.0 in acute respiratory failure are related to the severity of respiratory insufficiency.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The pharmacokinetics ofd-tubocurarine (dTc) during enflurane and during halothane anesthesia were compared in man. Seven patients received enflurane (1.3–1.4 per cent end-tidal) with nitrous oxide (70 per cent), while seven patients received an equipotent anesthetic concentration of halothane (0.5–0.7 per cent end-tidal) with nitrous oxide (70 per cent). Force of thumb adduction was used to assess paralysis. Using a rapid followed by a slower infusion ofdTc, relatively constant plasma concentrations were obtained within an hour and were maintained for one to two hours. To determine the effect of enflurane with nitrous oxide on force of thumb adduction, a control group of four patients did not receivedTc while thumb adduction was monitored for two to three hours. In the halothane-treated group, a constant plasma concentration ofdTc resulted in a constant degree of paralysis. With enflurane, however, a constant plasma concentration resulted in a time-dependent increase of paralysis, indicating an increased sensitivity of the neuromuscular junction todTc. In the control group, enflurane alone did not decrease the force of thumb adduction.The increase in paralysis in the enflurane-treated group was linear over a one to two hour period, with a mean increase of 9.0 per cent per hour. Evaluating only the first hour of enflurane anesthesia, the steady-state plasma concentration that caused 50 per cent paralysis (Cpss(50)was .52 ± .13 μg/ml (mean ± SD), while the Cpss(50)for halothane was significantly lower, .36 ± .04 μg/ml. Thus, during the first hour of enfluranne anesthesia, larger amounts ofdTc will be needed to initiate paralysis in comparison with halothane anesthesia. As the duration of enfluranne anesthesia increases, sensitivity todTc will progressively increase, and subsequent maintenance doses ofdTc needed will be smaller, relative to equipotent halothane anesthesia.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The incidence and degree of hypotension, time to establish surgical analgesia, and several other maternal and fetal variables were studied when 2-chloroprocaine, 3 per cent, and bupivacaine, 0.5 per cent, were used for epidural analgesia in 30 women undergoing elective cesarean section. Surgical analgesia occurred 8 min sooner (P< 0.001) with chloroprocaine (14 ± 1 min) than with bupivacaine (22 ± 2 min). Blood pressure values were significantly lower with chloroprocaine than with bupivacaine during the 18-to-32 min interval after local anesthetic injection, while pulse rates were higher (P< 0.05) at 18, 20, and 22 min. Hypotension necessitating treatment with ephedrine occurred in 33 per cent of chloroprocaine-treated subjects, compared with 13 per cent of those receiving bupivacaine. Newborn outcome was excellent in both groups, as reflected by umbilical vessel blood-gas values, times to sustained respiration, and 5-min Apgar scores. The authors conclude that chloroprocaine disturbs maternal cardiovascular status more than does bupivacaine when used for cesarean section epidural analgesia. However, chloroprocaine can be employed safely in normal pregnancies if maternal hypotension is corrected rapidly.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The effects of different levels of arterial blood oxygen content (CaO2) on brain tissue adenosine triphosphate (ATP), phosphocreatine (PCr), lactate, and reduced nicotinamide adenine dinucleotide (NADH) were studied during cerebral hypoxia in normothermic and hypothermic male Wistar rats with unilateral carotid ligation. Animals were exposed to hypoxia (PaO219–26 torr) for 25 min, and brain tissue metabolite values measured microfluorometrically were compared with those of normothermic normoxic controls. CaO2was 4.0 ± 0.2 ml/dl (mean ± SEM) at PaO226 torr in normothermic animals. CaO2was increased to 8.2 ± 0.3 ml/dl at PaO226 torr by means of bicarbonate infusion producing a leftward shift of the oxyhemoglobin-dissociation curve in one normothermic hypoxic group. In all normothermic hypoxic groups ATP and PCr decreased and lactate and NADH increased significantly compared with control values. There was no significant difference in brain tissue metabolite values among these groups despite an increase in CaO2by twofold in one group. Hypothermia (32 C) resulted in CaO28.4 ± 0.2 ml/dl at PaO226 torr. This was decreased to 4.0 ± 0.2 ml/dl by decreasing PaO2to 19 torr in another group at the same temperature. ATP and PCr were well preserved in both groups despite the difference in CaO2s. Although the lactate and NADH levels were increased in the hypothermic group with CaO24.0 ± 0.2 ml/dl, they were significantly lower than those values in normothermic hypoxic groups. These results indicate that the increase in CaO2produced by hypothermia is not a major determinant in hypothermic protection during cerebral hypoxia.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Numerous problems can occur with liquid oxygen delivery systems, in part because of the complexities of such systems. These systems must comply with guidelines of the Joint Commission on Accreditation of Hospitals. During the past year, 18 major problems with the liquid oxygen delivery system have occurred at the authors' hospital. Five times, false alarms have resulted from calibration drift in line pressure sensors. Thrice, excessive depletion of the reserve supply has occurred because of pressure imbalance between the main and reserve systems. Twice, excessive depletion of the reserve supply occurred owing to failure of the vacuum seal on the reserve supply vessel. Eight other potentially serious mishaps have also been reported. These problems, which are inherent in liquid oxygen delivery systems, are for the most part preventable.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID