ISSN:0003-3022    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Intracranial pressures (cisternal cerebrospinal fluid and brain surface pressures) were measured in nine anesthetized dogs during and after experimental hypercapnic hypoxia. Both pressures increased significantly after 20 minutes of hypoventilation with the hypoxic mixture (PaO220 ± 7.3 torr; PaCO287 ± 7.9 torr). When the dogs were subsequently hyperventilated with oxygen, the cerebrospinal fluid pressure rapidly declined, but pressure at the brain surface remained twice the control value. This pressure dissociation was even more striking when the dogs were then given an infusion of distilled water intraveously. These findings suggest that swelling of the brain occurs during hypercapnic hypoxia and is not reversed by an hour of hyperventilation. The lack of correlation between cisternal CSF and brain surface pressures suggests that CSF was displaced from the cranium while brain volume expanded. CSF pressure did not, therefore, reflect the actual pressure of the brain.

ISSN:0003-3022    

出版商:OVID    

年代:1972

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Depolymerization of neuronal microtubules has been proposed as the macromolecular event underlying general anesthesia. If so, rapid axoplasmic transport produced by microtubules should be reduced during anesthesia with halothane. Axonally migrating protein in the optic pathway of the rabbit was labeled by intraocular injection of3H-leucine. The distribution of radioactivity in the optic tract 2.5 hours later was examined in controls and in rabbits anesthetized with halothane. The control rate of transport was 240—300 mm/hour. Systematic slowing during anesthesia was not observed. Failure of the label to penetrate the second half of the optic tract was observed only in rabbits in which the blood halothane levels exceeded 0.0084 atm and body temperatures fell about 2 C. Slowed transport of label did not occur in anesthetized rabbits when body temperature was maintained at the same level as that of the controls. It is concluded that halothane anesthesia probably left microtubular function intact but that superadded minor hypothermia might have caused some impairment.

ISSN:0003-3022    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The clinical signs of anesthetic depth (heart rate, mean arterial pressure, pupil diameter, pupil reactivity to light, tearing, and eye movement) were correlated with anesthetic dose in healthy young volunteers. During halothane, halothane—nitrous oxide, Forane, or Forane–nitrous oxide anesthesia at normal PaCO2(controlled ventilation), only hypotension in the first hour of anesthesia correlated with anesthetic dose. After five hours of halothane or halothane–nitrous oxide, blood pressure remained constant as anesthetic concentration increased. During cyclopropane, diethyl ether, and fluroxene anesthesia, only pupillary dilatation and reduced pupil reactivity to light correlated with anesthetic dose. When nitrous oxide was added to halothane, ether, or fluroxene, mean arterial pressure rose and pupils dilated. During halothane–oxygen anesthesia with spontaneous ventilation, the rise in PaCO2allowed less hypotension and increased heart rate. Tidal volume decreased and respiratory rate increased as anesthesia deepened. During Forane–oxygen anesthesia with spontaneous respiration, mean arterial pressure, tidal volume, and minute ventilation decreased as anesthesia deepened. In healthy surgical patients anesthetized with halothane or Forane only, incision of the skin modified the clinical signs significantly. While surgery continued, this change in clinical signs persisted during Forane anesthesia, but returned to control during halothane anesthesia.

ISSN:0003-3022    

出版商:OVID    

年代:1972

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The Interaction of caffeine with pentobarbital taken for its hypnotic effect was studied in 42 medical and surgical patients. Each patient received the following medications orally: a lactose placebo; 250 mg caffeine; 100 mg pentobarbital; and 250 mg caffeine plus 100 mg pentobarbital. Hypnotic effects were determined by patient evaluation of sleep. Caffeine had an adverse effect on sleep, whereas pentobarbital was an effective hypnotic. Together, their effects appeared additive, and the 250 mg caffeine plus 100 mg pentobarbital combination was not distinguishable from the placebo.

ISSN:0003-3022    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Inherited susceptibility to malignant hyperthermia has been recognized in Poland China swine. Clinical and laboratory studies were made to compare the syndrome with that observed in man and in other breeds of swine in South Africa and Europe. Malignant-hyperthermia-susceptible (MHS) swine were identified by increased ATP depletion in biopsied muscle studiedin vitro. MHS and related swine had elevated serum creatine phosphokinase values compared with control swine (MHS swine &OV0335; 2,435 IU/l; MHS-related swine &OV0335; 1,260 ID/l; control swine &OV0335; 144 IU/l). The syndrome was triggered by administration of halothane and of succinylcholine chloride. Resulting clinical responses, in order of appearance, were tachycardia, hyperventilation, skeletal muscle rigidity, hyperthermia, cardiac arrhythmias, and death. Blood chemical responses which occurred early in the syndrome included hypercapnia, acidosis, elevated plasma inorganic phosphorus, and lactacidemia. The malignant hyperthermia syndrome in this breed of swine appears similar to that in Land-race and Pietrain swine, and in man. The Poland China swine is an appropriate animal model for the study of this disease.

ISSN:0003-3022    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Compared with muscle from normal swine, muscle slices from a strain of malignant-hyperthennia-susceptible (MHS) swinein vitroshowed greater depletion of ATP and greater production of lactate, and halothane increased the ATP depletion and lactate production in MHS muscle slices. No difference between the calcium uptake capacities of specimens of sarcoplasmic reticulum isolated from normal and from MHS swine was detected. Halothane increased the amounts of Ca++bound by sarcoplasmic reticulum from both control and MHS muscle. The data suggest an underlying myopathy in MHS muscle, the nature of which appears to be rapid utilization of muscle ATP and loss of glycolytic control mechanisms.

ISSN:0003-3022    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The gas–hydrate theory of anesthesia proposed by Pauling and Miller suggests that either synergism or antagonism can occur when anesthetics are combined. Using MAC as a standard for depth of anesthesia, the properties of MAC fractions in combinations of anesthetics were evaluated and found to be additive, with the following exception: the combination of cyclopropane with nitrous oxide or ethylene produced antagonism. This result may be explained by competition of these agents for the same cavities in the hydrate structure.

ISSN:0003-3022    

出版商:OVID    

年代:1972

数据来源: OVID