Cardiovascular effects of halothane in man.
TL;DR: The author examined the cardiovascular effect of halothane in 15 unmedicated volunteers under moditions of constant arterial carbon dioxide tension and body temperature to find out whether peripheral resistance fell and heart rate increased with progressive duration of anesthesia.
Abstract: The author examined the cardiovascular effect of halothane in 15 unmedicated volunteers under moditions of constant arterial carbon dioxide tension and body temperature. Compared with awake measurements, the effects during the first hour of anesthesia included depression of enrdiac output, stmke volume, arterial pressure, left ventricular minute and stroke work, and myocardial contractility (as evidenced by the ballistocardiogram IJ-wave amplitude), muscle blood flow, and total body oxygen consumption. Mean right atrial pressure incrensed. These efeect were directly related to halothane concentration. Total peripheral resistance and heart rate were unchnnged and, at lighter anesthetic levels, skin blood flow increased. After five hours of anesthesia saveral values returned to towards or above awake values. These were: cardiac output, stroke volume, left ventricular work or stroke work, IJ-wave amplitude, muscle blood flow, and mean right atrial pressure. Told peripheral resistance fell and heart rate increased with progressive duration of anesthesia.
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TL;DR: Sevoflurane with nitrous oxide provides satisfactory anesthetic induction and intubating conditions; however, induction using sevoflURane without nitrousoxide is associated with a high incidence of patient excitement and prolonged time to intubation.
Abstract: BackgroundFor pediatric patients, sevoflurane may be an alternative to halothane, the anesthetic agent used most commonly for inhalational induction. The induction, maintenance, and emergence characteristics were studied in 120 unpremedicated children 1–12 yr of age randomly assigned to receive one
250 citations
TL;DR: The characteristics of the top 100 most frequently cited articles published in anesthetic journals are identified and analysis of citation rates allows for the recognition of seminal advances in anesthesia and gives a historic perspective on the scientific progress of this specialty.
Abstract: UNLABELLED The number of citations an article receives after its publication reflects its recognition in the scientific community. In the present study, therefore, we identified and examined the characteristics of the top 100 most frequently cited articles published in anesthetic journals. These articles were identified using the database of the Science Citation Index Expanded (SCI-EXPANDED, 1945 to present) and the Web of SCIENCE(R). The most-cited article received 707 citations and the least cited article received 197 citations, with a mean of 283 citations per article. These citation classics were published between 1954 and 1997 in 5 high-impact anesthetic journals, led by Anesthesiology (73 articles) followed by Anesthesia & Analgesia (10), British Journal of Anesthesia (10), Anesthesia (6), and Acta Anaesthesiologica Scandinavica (2). Seventy-eight articles were original publications, 22 were review articles, and one was an editorial. They originated from nine countries, with the United States contributing 70 articles. Within the United States, California leads the list of citation classics with 25 articles. Twenty-nine persons authored two or more of the top-cited articles. The main topics covered by the top-cited articles are pharmacology, volatile anesthetics, circulation, regional anesthesia, and lung physiology. This analysis of citation rates allows for the recognition of seminal advances in anesthesia and gives a historic perspective on the scientific progress of this specialty. IMPLICATIONS We performed a citation analysis to identify important contributions and contributors to the anesthetic literature. These classic articles have influenced many people and have brought to our attention the many important advances in anesthesia made during the last 50 yr.
248 citations
TL;DR: The authors evaluated the hemodynamic effects of sevoflurane in healthy volunteers not undergoing surgery to establish an understanding of the detailed cardiovascular properties of an anesthetic.
Abstract: BackgroundSevoflurane is a new inhalational anesthetic with desirable clinical properties. In some clinical situations, an understanding of the detailed cardiovascular properties of an anesthetic is important, so the authors evaluated the hemodynamic effects of sevoflurane in healthy volunteers not
214 citations
TL;DR: These features combined with its favourable cardiovascular profile should make sevoflurane the agent of choice for inhalation induction in adult and paediatric anaesthesia and prove to be a valuable alternative anaesthetic agent for adults in both outpatient and inpatient surgery.
Abstract: Sevoflurane is an ether inhalation general anaesthetic agent with lower solubility in blood than isoflurane or halothane but not desflurane. The low solubility and the absence of pungency facilitate rapid mask induction; the low blood solubility also expedites "wash-out' and therefore recovery from anaesthesia. Sevoflurane produces dose-dependent CNS, cardiovascular and respiratory depressant effects that generally parallel those of isoflurane. Sevoflurane is degraded by carbon dioxide absorbents to nephrontoxic (in rats) haloalkenes, although renal toxicity has not been observed in humans. Compared with other inhalation anaesthetics, negligible quantities of carbon monoxide are generated from degradation of sevoflurane by carbon dioxide absorbents. Sevoflurane has negligible airway irritant effects, which facilitates a "smooth' induction, even in comparison with halothane in paediatric patients, and makes sevoflurane especially amenable to rapid induction of anaesthesia in adults and children. Emergence, orientation an postoperative cognitive and psychomotor function recovery of paediatric outpatients is singnificantly more rapid from sevoflurane than from halothane anaesthesia. In adult inpatients and outpatients, emergence and orientation are significantly faster after sevoflurane than after isoflurane but not desflurane anaesthesia. Other recovery parameters (e.g. times to sitting, ambulation) occur at similar times after either sevoflurane or desflurane anaesthesia. Recovery of psychomotor function occurs at generally similar times after sevoflurane, isoflurane or desflurane. Compared with propofol, sevoflurane facilitates more predictable extubation times and significantly better postoperative modified Aldrete scores in outpatients, although cognitive and psychomotor recovery occurs at similar times for both agents. As a supplement to opioid anaesthesia during coronary bypass graft surgery or in those at risk for myocardial ischaemia, sevoflurane is comparable to isoflurane. Limited data suggest that it is also as useful as isoflurane for the maintenance of anaesthesia during neurosurgical or obstetric procedures. Sevoflurane is well tolerated by adult and paediatric patients during induction of anaesthesia, with a low incidence of mild airway complications (breath-holding, coughing, excitement and laryngospasm). During rapid induction, it is particularly better tolerated than isoflurane or halothane. Sevoflurane has a lower potential for hepatic injury than halothane. Unlike methoxyflurane, sevoflurane undergoes minimal intrarenal defluorination, which may account for the lack of fluoride ion-induced nephrotoxicity in humans, despite elevated plasma fluoride levels after its use. In summary, sevoflurane provides for a rapid and smooth induction of, and recovery from, anaesthesia. These features combined with its favourable cardiovascular profile should make sevoflurane the agent of choice for inhalation induction in adult and paediatric anaesthesia. Although further clinical evaluation will define the role of this agent relative to that of propofol and desflurane, sevoflurane should also prove to be a valuable alternative anaesthetic agent for adults in both outpatient and inpatient surgery.
189 citations
TL;DR: The margin ofsafety between concentrations of cnflurane required for surgical anesthesia and hazardous concentrations is less during controlled ventilation than is the margin of safety associated with other potent inhalation anesthetics.
Abstract: We studied the cardiovascular effects of enflurane in 12 unpremedicated volunteers without surgery under conditions of constant arterial CO, tension and body temperature. During the first hour of anesthesia 1 MAC (1.86% end-tidal) was associated with decreased cardiac output (CO) by 25.9%, stroke volume (SV) by 39.6%, systemic vascular resistance (SVR) by 16.1%, IJ wave of the ballistocardiogram (Beg) by 39%. and aortic dP/dt by 60.7% compared to awake values. Heart rate (HR) increased 22.4%, but blood pressure (BP) declined by 36%. Central venous pressure (CVP) rose less than 1 torr. Plethysmographic measurements of finger (skin) and forearm (muscle) blood flow did not significantly change from awake levels, but forearm vascular resistance was reduced. An increase to 1.5 MAC caused further declines in SV, aortic dP/dt, and Bcg, but not in BP or CO. Heart rate increased and the CVP rose 3.8 torr above control. Two MAC enflurane could not be achieved without progressive and profound hypotension.During the sixth hour of continuous anesthesia, we observed some recovery of cardiovascular performance. Cardiac output, SV, and aortic dP/dt returned toward awake levels at 1 MAC, but not at 1.5 MAC. Systemic vascular resistance declined during the interval, and BP remained unaltered.The margin of safety between concentrations of cnflurane required for surgical anesthesia and hazardous concentrations is less during controlled ventilation than is the margin of safety associated with other potent inhalation anesthetics.
130 citations