Showing papers in "Anesthesiology in 1971"
TL;DR: There are many words in the English language to describe the varieties of pain experience, and there is a high level of agreement that the words fall into classes and subclasses that represent particular dimensions or properties ofPain experience.
Abstract: The purpose of this study was to develop new approaches to the problem of describing and measuring pain in human subjects. Words used to describe pain were brought together and categorized, and an attempt was made to scale them on a common intensity dimension. The data show that: 1) there are many w
982 citations
TL;DR: The cardiovascular effects of Forane, a new inhalation anesthetic, were examined in seven un-medicated volunteers under conditions of constant arterial carbon dioxide tension and body temperature and demonstrated maintenance of myocardial function but progressive vasodilatation as anesthesia deepened.
Abstract: The cardiovascular effects of Forane, a new inhalation anesthetic, were examined in seven un-medicated volunteers under conditions of constant arterial carbon dioxide tension and body temperature. Comparison of results during anesthesia with awake values demonstrated maintenance of myocardial function but progressive vasodilatation as anesthesia deepened. No significant changes in the cardiac output, ballistocardiogram I-J wave amplitude, ejection time, mean rate of ventricular ejection, or pre-ejection period occurred with onset or deepening of anesthesia. Arterial pressure decreased, as did total peripheral resistance. Increased muscle and skin blood flow and forearm venous compliance suggested that the loss of resistance was due in part to dilatation of vessels in the skin and muscles. Cardiac output was maintained by an increased heart rate which compensated for the decreased stroke volume. Comparisons of results during the first and fifth hours of anesthesia demonstrated only minor changes with increased duration of anesthesia. These included further increases in forearm blood flow and an increase in base excess.
321 citations
TL;DR: A survey was undertaken to evaluate the possible relationship between spontaneous miscarriage and exposure to the operating room, and results indicate that during the years 1966-1970, 29.7 per cent of pregna were affected.
Abstract: A survey was undertaken to evaluate the possible relationship between spontaneous miscarriage and exposure to the operating room. The study was carried out by personal interview of 67 operating room and 92 general duty nurses. Results indicate that during the years 1966–1970, 29.7 per cent of pregna
302 citations
TL;DR: Evidence is presented to suggest that inorganic fluoride is the substance responsible for methoxyflurane; induced renal dysfunction, and a proposed metabolic pathway to support this hypothesis is presented.
Abstract: Serun inorganic fluoride concentration and urinary inorganic fluoride and oxalic acid excretion were found to be markedly elevated in ten patients previously shown to have methoxyflurane-induced renal dysfunction. Five patients with climically evident renal dysfunction had a mean peak serum inorganic fluoride level (190.4 ± 20.9 μ/1) significantly higher (P
213 citations
TL;DR: It is proposed that a portion of the brainstem reticular formation exerts a tonic inhibitory effect on transmission at all levels of the somatic projection system, which would underlie prolonged pain and spread of trigger zones.
Abstract: The mechanisms underlying pathologic pain states such as phantom limb pain remain a mystery. Observations that 1) pain may persist indefinitely; 2) trigger zones may spread to healthy parts of the body; and 3) pain may be abolished by either decreasing or increasing the sensory input cannot be explained solely in terms of peripheral causes or abnormal activity restricted to the spinal cord. This paper proposes that a portion of the brainstem reticular formation exerts a tonic inhibitory effect on transmission at all levels of the somatic projection system. The loss of sensory input after amputation would decrease the tonic inhibition and increase the probability of self-sustaining neural activity. The self-sustaining activity, its capacity to recruit adjacent neurons, and its occurrence at several transmission levels would underlie prolonged pain and spread of trigger zones. Modulation of the sensory input by anesthetic blocks or intense stimulation would abolish the self-sustaining activity and produce pain relief.
190 citations
TL;DR: The biotransformation of Ēthrane was studied in seven healthy female patients by measuring urinary fluorine excretion, with results indicating that following anesthesia, urinary excretion rates of fluoride in reached a maximum in seven hours, and maximum excretion of organic fluorine metabolites was reached on the second day.
Abstract: The biotransformation of Ēthrane was studied in seven healthy female patients by measuring urinary fluorine excretion. The total amount of Ēthrane recovered was 85.1 per cent of the amount absorbed; 82.7 ± 18.8 per cent was recovered as unchanged Ēthrane in exhaled air and 2.4 per cent as nonvolatile fluorinated metabolites in urine. Of the urinary fluorine, 0.5 per cent was excreted in inorganic form and 1.9 per cent in organic form. Following anesthesia, urinary excretion rates of fluoride in reached a maximum in seven hours. Maximum excretion of organic fluorine metabolites was reached on the second day. Urinary excretion then assumed a simple exponential decay, with half-times of 1.53 days for inorganic fluoride and 3.69 days for or-ganic fluorine. The excretion of unaltered Ēthrane in exhaled air assumed a three-term exponential decay, with half-times of 17.8 minutes, 3.2 hours, and 36.2 hours.
155 citations
TL;DR: The EEG patterns of increasing depths of Ēthrane-O2 anesthesia and the alterations in the patterns produced by changing Paco2 and by addition of 60 per cent nitrous oxide have been evaluated in 30 individuals.
Abstract: The EEG patterns of increasing depths of Ēthrane-O2 anesthesia and the alterations in the patterns produced by changing Paco2 and by addition of 60 per cent nitrous oxide have been evaluated in 30 individuals. Increasing depth of anesthesia was characterized by the appearance of high-voltage spikes,
123 citations
120 citations
TL;DR: A significant reduction in atmospheric contamination of the operating room was obtained by use of appropriate scavenging equipment and the scavenging system employed to remove overflow anesthetic gases.
Abstract: Halothane present in the ambient atmosphere was continuously measured in each of two operating rooms during the conduct of surgical anesthesia. Concentrations were determined on-line with a mass spectrometer and found to vary with sampling site, breathing system used, and the scavenging system employed to remove overflow anesthetic gases. Concentrations of halothane measured within a 3-foot radius of the anesthesia equipment averaged 8.7 ppm when a nonrebreathing circuit was used (flow 10 l/min), and 4.9 ppm with a semiclosed circle system (flow 4–5 l/min). End-tidal concentrations of halothane averaged 0.21 ppm in 81 samplings from operating room nurses and 0.46 ppm in 36 samplings from anesthetists. Residual concentrations were present in many individuals 16 hours after exposure. A significant reduction in atmospheric contamination of the operating room was obtained by use of appropriate scavenging equipment. The implications of these findings are discussed.
117 citations
TL;DR: The kinetics of disposition of lidocaine after intravenous regional anesthesia of the arm and direct intravenous infusion were studied in volunteers, finding release of drug into the systemic circulation was found to be biphasic, an initial fast release of about 30 per cent of the dose followed by a gradual washout of the remainder.
Abstract: The kinetics of disposition of lidocaine after intravenous regional anesthesia of the arm and direct intravenous infusion were studied in volunteers. Plasma levels of the drug in blood samples from a contralateral artery and in some cases also from the pulmonary artery and a contralateral vein were
116 citations
TL;DR: The influence of epinephrine on the cardiovascular effects of high (T5) peridural analgesia was studied in 19 human volunteers and lidocaine–epinephrine solution caused a significantly greater decrease in TPR, and consequently in MAP, and a greater increase in leg blood flow than did saline–epinphrine solution.
Abstract: The influence of epinephrine on the cardiovascular effects of high (T5) peridural analgesia was studied in 19 human volunteers, each of whom received two injections. In 12, the effects of lidocaine alone were compared with those of lidocaine–epinephrine. Peridural analgesia with lidocaine alone produced small (5 to 10 per cent) changes in cardiac output (CO), total peripheral resistance (TPR) and mean arterial pressure (MAP). During peridural analgesia with Iidocaine–epinephrine a 49 per cent increase in CO and a 37 per cent decrease in TPR resulted in a 10 per cent decrease in MAP. All of these changes from control were statistically significant and were significantly greater than those produced by lidocaine alone. In another seven subjects, the effects of peridural injection of lidocaine–epinephrine were compared with those of injection of saline–epinephrine. The two solutions produced similar effects on the heart, but lidocaine–epinephrine solution caused a significantly greater decrease in TPR, and consequently in MAP, and a greater increase in leg blood flow than did saline–epinephrine solution.
TL;DR: Isolated cat papillary muscles driven at a rate of 12 beats/min at 37.5 C were exposed tojeoncen-trations of cyclopropane, diethyl ether, Ethrane, halothanc, and methoxyflurane similar to those required to produce general anesthesia m vivo, implying a common mode of action on the con-tractile process.
Abstract: Isolated cat papillary muscles driven at a rate of 12 beats/min at 37.5 C were exposed tojeoncen-trations of cyclopropane, diethyl ether, Ethrane, halothanc, and methoxyflurane similar to those required to produce general anesthesia m vivo. Each anesthetic depressed peak developed ten-sion, maximal dp/dt, and the force-time integral of the twitch, and each shortened the time to peak tension. These variables were altered in qualitatively similar ways by all anesthetics tested, implying a common mode of action on the con-tractile process. When administered in cquieffec-tivc concentrations from the standpoint of producing general anesthesia (i.e at equal MAC's), the order of activity of the anesthetics in depressing contractility (from most to least depressant) was: Ethrane > halothanc > methoxyflurane > cyclopropane > diethyl ether.
TL;DR: With Forane, production of arrhythmias required progressively more epinephrine as Paco2 increased, and with halothane and fluroxene, the same trend was present, but it was not significant.
Abstract: The effect of Forane on epinephrine-induced cardiac arrhythmias was tested in dogs by comparing it with halothane and fluroxene. The doses of epinephrine necessary to produce two or more premature ventricular contractions at 1.25 and 2.0 MAC and at Paco2's of 20, 40, and 80 torr were determined. Only 14 to 22 per cent as much epinephrine as in the awake state was needed to produce arrhythmias during halothane anesthesia. The amounts of epinephrine which induced arrhythmias during fluroxene and Forane anesthesia did not differ from the values in awake animals, With Forane, production of arrhythmias required progressively more epinephrine as Paco2 increased. With halothane and fluroxene, the same trend was present, but it was not significant. As depth of anesthesia increased, more epinephrine was needed to produce arrhythmias with all agents tested.
TL;DR: The neuromuscular effects of pancuronium were studied in 65 patients anesthetized with nitrous oxide supplemented by thiopental and/or meperidine and there was a marked variation among patients in their responses to Pancuronium.
Abstract: The neuromuscular effects of pancuronium were studied in 65 patients anesthetized with nitrous oxide supplemented by thiopental and/or meperidine. There was a marked variation among patients in their responses to pancuronium. A dose of 0.02 mg/kg depressed twitch height 44 per cent. Recovery to 90 per cent of control twitch height took 16 minutes. With repeated doses a cumulative effect was observed. A dose of 0.04 mg/kg produced an 88 per cent block. Twitch height recovered to 90 per cent of control in 58 minutes. After a dose of 0.08 mg/kg the twitch response was markedly depressed (>98 per cent) or abolished, and the trachea could be intubated with ease. Recoveries to 10 and 25 per cent of control took 65 and 86 minutes, respectively. During a partial block, tetanus was usually poorly sustained and posttetanic facilitation was observed.
TL;DR: Forane-induced EEG changes can be distinguished from those seen with other anesthetics by the maintenance of high-frequency activity at any level where EEG activity is present, and depth of anesthesia can be monitored with the EEG.
Abstract: Electroencephalograms (EEC) of seven healthy male volunteers anesthetized with Forane were studied. Body temperature and Paco2 were maintained at normal levels except that hypocapnia was transiently induced once or twice during each study. Increasing doses of Forane produced increasing periods of bu
TL;DR: Succinylcholine-induced muscle fasciculations may be prevented by pretreatment with small doses of nondepolarizing muscle relaxants, but such pretreatment may increase the difficulty of tracheal intubation by antagonizing succinylCholine (SCh) depolarization.
Abstract: Succinylcholine-induced muscle fasciculations may be prevented by pretreatment with small doses of nondepolarizing muscle relaxants. Such pretreatment, however, may increase the difficulty of tracheal intubation by antagonizing succinylcholine (SCh) depolarization. To determine which drugs and doses
TL;DR: In contrast to halothane, Forane in increasing concentrations did not cause progressive increases in respiratory frequency, and this depression results from a unique failure of respiratory frequency to increase with increasing depth of anesthesia.
Abstract: The ventilatory effects of Forane were studied in ten volunteers and compared with values obtained in eight volunteers anesthetized with halothane. Paco2 averaged 60 torr with both 1.9 per cent alveolar Forane (approximately 1.45 X MAC) and 1.6 per cent halothane (1.9 X MAC). The slopes of the CO2 response curves were depressed to 30 ± 6 per cent (Mean ± SE) of awake control values by 1.28 per cent Forane (approximately 1.0 X MAC) and to 45 ± 7 per cent of controls with 1.05 per cent halothane (1.25 X MAC). Therefore, when equivalent anesthetic doses are considered, less Forane than halothane was needed to increase Paco2 and depress the slope of the CO2 response curve. In contrast to halothane, Forane in increasing concentrations did not cause progressive increases in respiratory frequency. At equal multiples of MAC, Forane produces more profound respiratory depression than halothane, and this depression results from a unique failure of respiratory frequency to increase with increasing depth of anesthesia.
TL;DR: It is suggested that recovery of the response to tetanic stimulation at 100/sec would provide a practical index of adequate recovery from curarization.
Abstract: The relation between receptor occlusion by a competitive neuromuscular blocking agent and fade of an indirectly elicited tetanus at frequencies of 30, 100 and 200/sec has been determined. Tetanic fade at 30/sec returned to normal when one-fifth to one-quarter of the receptors became available, and t
TL;DR: It was concluded that the ketamine-induced anesthetic state is a result of functional disorganization of the CNS rather than CNS depression, and there is little or no possibility that ketamine induces dream sleep in the cat.
Abstract: The effects of ketamine on CNS electrical activities (EEC and multiple-unit activity of the brain-stem core) and gross behavior were studied in cats with chronically implanted electrodes. Ketamine induced three distinct patterns, related to dose An initial CNS excitation coupled with catatonic behavior was followed by disorganized excitation characterized by a catatonie-anesthetic state and finally, electrographic seizures without clinical correlates. During the initial period multiple-unit activity increased. Following this, the basal level of multiple-unit activity decreased, but the level increased phasically in synchrony with EEG hypersynchrony. During the stage of generalized seizures, the basal level decreased further, while phasic enhancement was not much affected. Comparison of polygraphic findings in the ketamine-induced anesthetic state and during control paradoxical (dream) sleep revealed that there is little or no possibility that ketamine induces dream sleep in the cat. Comparison of ketamine anesthesia and states induced by other hallucinogenic and convulsant drugs, including anesthetics, indicated some possibility that ketamine induces hallucinations. It was concluded that the ketamine-induced anesthetic state is a result of functional disorganization of the CNS rather than CNS depression.
TL;DR: The minimum alveolar concentration (MAC) of enflurane in man was found to be 1.68 per cent, a value close to that which would have been predicted, based on its lipid solubility.
Abstract: The minimum alveolar concentration (MAC) of enflurane in man was found to be 1.68 per cent, a value close to that which would have been predicted, based on its lipid solubility.
TL;DR: In human volunteers, Forane failed to alter twitch height, but increased average neuromuscular refractory period and prevented a sustained response to stimulation at higher frequencies of tetanus and these effects were dose-related.
Abstract: In human volunteers, Forane failed to alter twitch height, but increased average neuromuscular refractory period and prevented a sustained response to stimulation at higher frequencies of tetanus. These effects were dose-related. Surgical patients anesthetized with 1.25 MAC Forane were unable to sustain tetanus at more than 120 Hz. In contrast, patients anesthetized with 1.25 MAC halothane were able to sustain tetanus at 200 Hz. In 15 patients anesthetized with 1.25 MAC Forane, the median effective dose of d-tubocurarine needed to produce a 50 per cent depression of twitch height (ED50) was 1.70 mg/m2. In contrast, the ED50 of d-tubocurarine in 17 patients anesthetized with 1.25 MAC halothane was 5.69 mg/m2. Thus, 3.3 times as much d-tubocurarine was needed to produce a 50 per cent depression of twitch height with halothane.
TL;DR: Pancuronium, gallamine, and succinylcholine produced more profound neuromuscular blockade in 36 patients anesthetized with 1.25 MAC Forane than in 36 Patients anesthenized with 2 MAC halothane.
Abstract: Pancuronium, gallamine, and succinylcholine produced more profound neuromuscular blockade in 36 patients anesthetized with 1.25 MAC Forane than in 36 patients anesthetized with 1.25 MAC halothane. The median effective dose of pancuronium necessary to produce 50 per cent depression of twitch height (ED20) was 0.27 mg/m2 during Forane and 0.49 mg/m2 during halothane anesthesia, giving a halothane/Forane potency ratio of 1.8. The ED20 of gallamine was 9.4 mg/m2 during Forane anesthesia and 22.5 mg/m2 during halothane anesthesia, for a potency ratio of 2.4. The ED20 of succinylcholine was 3.4 mg/m2 during Forane anesthesia and 5.1 mg/m2 during halothane anesthesia, for a potency ratio of 1.5.
TL;DR: The evidence indicates that diazepam depresses the ventilatory response to CO2, and also modifies the characteristics of gas exchange within the lung, producing a rise in VD/VT, and often associated with a Rise in Pactco2.
Abstract: The effects of diazepam (0.14 mg/kg) on steady-state gas exchange were studied in 13 patients, and the responses to a carbon dioxide stimulus using a recently introduced rebreathing technique are described. There were significant increases in VD/VT and Paco2, and a decrease in VT. E and o2- were unc