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  • 1
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Remifentanil ; Propofol ; Isofluran ; Aufwachverhalten ; Shivering ; Key words Remifentanil ; Propofol ; Isoflurane ; Recovery times ; Shivering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Objectives: Due to its unique pharmacokinetics, the new esterase-metabolised opioid remifentanil results in rapid post-anaesthesia recovery. The aim of this clinical investigation was to compare recovery times after remifentanil anaesthesia in combination with hypnotic concentrations of either propofol or isoflurane. Dosages used in the study protocol were based on recommendations by the pharmaceutical manufacturer. Methods: Patients (ASA status I–II) scheduled for elective arthroscopy were included in this trial. Without premedication in the morning, anaesthesia was induced identically in both groups: remifentanil bolus (1 µg/kg), start of remifentanil-infusion (0.5 µg/kg/min), followed immediately by propofol (ca. 2 mg/kg). For maintenance of anaesthesia remifentanil (0.25 µg/kg/min) was combined with either a propofol infusion of 0.1 mg/kg/min or 0.5 MAC isoflurane (=0.6 vol.%) in O2/air. Anaesthetic delivery was discontinued simultaneously with termination of surgery and recovery times were recorded. Results: A total of 40 patients were studied at random in two groups of 20 each with comparable demographic data and anaesthetic technique (Tables 1 and 2). In both groups emergence was very rapid. Recovery times were significantly shorter for remifentanil-isoflurane than for remifentanil-propofol (Table 3): spontaneous ventilation 5.1 vs 8.1 min (P〈0.05), extubation 5.5 vs. 8.6 min (P〈0.02), post-anaesthesia recovery score ≥9 of 10 points 6.2 vs 11.3 min (P〈0.01), and arrival at PACU 16.2 vs 19.2 min (P〈0.01). Mild to moderate shivering was noted in 40% of all patients (9 cases following isoflurane, 7 following propofol). Conclusions: Using the manufacturer’s recommended dosages, emergence after remifentanil anaesthesia is more rapid with 0.5 MAC isoflurane than with 0.1 mg/kg/min propofol. These results are most probably due to the different pharmacological properties of both co-anaesthetics, especially the applied dosages, and to different interactions with remifentanil. Present clinical experience suggests that a further dose reduction, especially for propofol, is possible. For both remifentanil groups emergence was remarkably rapid between return of consciousness and the awake state (on-off phenomenon), which might contribute to post-anaesthesia safety.
    Notes: Zusammenfassung Das neue Opioid Remifentanil wird rasch durch unspezifische Blut- und Gewebeesterasen metabolisiert und läßt so kurze Aufwachzeiten erwarten. In der vorliegenden klinischen Untersuchung sollte das Aufwachverhalten bei Kombination von Remifentanil mit Propofol oder Isofluran in hypnotisch wirksamen Konzentrationen verglichen werden. Methodik: Untersucht wurden 40 Patienten (ASA I–II), die sich einer elektiven Arthroskopie unterziehen mußten. Die Narkoseeinleitung war in beiden Gruppen identisch: Remifentanilbolus (1 µg/kg), Beginn der Remifentanilinfusion (0,5 µg/kg/min), sofort anschließend Propofol (ca. 2 mg/kg). Die weitere Narkoseführung erfolgte mit Remifentanil 0,25 µg/kg/min in Kombination mit 0,1 mg/kg/min Propofol oder mit 0,5 MAC Isofluran (=0,6 Vol.-%) in O2/Luft. Die Anästhetikazufuhr wurde erst mit der letzten Hautnaht beendet und die üblichen Aufwachzeiten ermittelt. Ergebnisse: In beiden Gruppen (je n=20) benötigte der Aufwachvorgang zwischen beginnender Rückkehr des Bewußtseins und vollständiger Wachheit nur ca. 90 s. Dabei waren die Aufwachzeiten in der Remifentanil-Isoflurangruppe signifikant kürzer als in der Remifentanil-Propofolgruppe: Spontanatmung im Mittel nach 5,1 vs. 8,1 min (p〈0,05), Extubation nach 5,5 vs. 8,6 min (p〈0,02). Diskussion: Bei der vom Hersteller empfohlenen Dosierung verlief die Aufwachphase nach Remifentanil mit 0,5 MAC Isofluran signifikant schneller als bei der Kombination von Remifentanil mit 0,1 mg/kg/min Propofol. Bisherige klinische Erfahrungen lassen vermuten, daß insbesondere die Propofoldosis weiter reduziert werden kann. Die für beide Remifentanilgruppen bemerkenswert kurze Zeitspanne zwischen beginnender Rückkehr des Bewußtseins und anschließend vollständiger Wachheit ohne Atemdepression (ON-OFF-Phänomen) kann zur postanästhesiologischen Sicherheit beitragen.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Remifentanil ; Propofol ; Desfluran ; Aufwachverhalten ; kardiovaskuläre Effekte ; Key words Remifentanil ; Propofol ; Desflurane ; Cardiovascular effects ; Emergence times
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Objective: To ascertain whether there is a difference between total intravenous anaesthesia with propofol (P) and remifentanil (R) and inhalational anaesthesia with desflurane (D) and nitrous oxide (N) with regard to haemodynamic reactions, recovery profile and postoperative analgesic demand in patients scheduled for elective microsurgical vertebral disc resection. Methods: 50 patients (ASA I–II, 18–65 years) were randomly assigned to receive total intravenous anaesthesia with propofol and remifentanil or inhalational anaesthesia with desflurane and nitrous oxide. After standardised induction of anaesthesia in both groups (1 µg·kg−1 remifentanil, 1.5 mg·kg−1 propofol, 0.1 mg·kg−1 cisatracurium), anaesthesia was maintained in the D/N group with desflurane in 50% N2O. The patients of the P/R group received a constant infusion of 2 mg·kg−1·h−1 propofol and a constant infusion of 0.5 µg·kg−1·min−1 remifentanil, which was reduced after 15 min by 50%. The administration of desflurane and the infusion of the anaesthetics were adjusted to maintain a surgical depth of anaesthesia. At the end of surgery the anaesthetics were discontinued and early emergence from anaesthesia was assessed by measuring time to spontaneous ventilation (VT〉4 ml/kg), tracheal extubation, opening of the eyes and stating correct name and data of birth. The frequency of analgesics and total demand for analgesics were determined using patient-controlled analgesia and recorded for 2 h postoperatively. In addition the pain level of the patients was measured on a visual analogue scale and the incidence of postoperative shivering, nausea and vomiting was noted. Results: Patients anaesthetised with desflurane responded to tracheal intubation and skin incision with increasing blood pressure and showed higher heart rates than patients anaesthetised with propofol and remifentanil, but there were no other haemodynamic differences between the groups in response to surgical stimuli. There were significantly shorter times to spontaneous ventilation (3.2 vs. 6.3 min), extubation (3.8 vs. 9.5 min), eye opening (3.0 vs. 11.5 min) and giving name and date of birth (4.8 vs. 14.3 min) in patients anaesthetised with remifentanil and propofol than in those receiving desflurane and nitrous oxide. In addition, patients anaesthetised with remifentanil and propofol had a greater incidence of postoperative shivering. There were no significant differences between the two groups in the patients’ pain scores, analgesic demand and incidence of nausea and vomiting. Conclusion: Patients anaesthetised with propofol and remifentanil have significantly shorter emergence times than patients anaesthetised with desflurane and nitrous oxide. The low incidence of postoperative pain after microsurgical vertebral disc resections requires no large-scale analgesic therapy, even after total intravenous anaesthesia including remifentanil.
    Notes: Zusammenfassung Fragestellung: Unterscheidet sich eine totale intravenöse Anästhesie mit Propofol (P) und Remifentanil (R) von einer Inhalationsanästhesie mit Desfluran (D) und Lachgas (L) bei lumbalen Bandscheibenoperationen hinsichtlich der Steuerbarkeit der Narkose, der Beeinflussung hämodynamischer Parameter, des Aufwachverhaltens und des postoperativen Analgetikabedarfs der Patienten? Methodik: 50 Patienten (ASA I–II, 18–65 Jahre) wurden randomisiert entweder einer P/R- oder D/L-Gruppe zugeteilt. Nach standardisierter Narkoseeinleitung (1 µg/kg Remifentanil, 1,5 mg/kg Propofol, 0,1 mg/kg Cisatracurium) wurde die Anästhesie in der D/L-Gruppe bedarfsadaptiert mit Desfluran in 50% N2O und in der P/R-Gruppe mit 2 mg/kg/h Propofol und 0,5 µg/kg/min Remifentanil aufrechterhalten, wobei die Remifentanildosis nach 15 min halbiert wurde. Am Operationsende unmittelbar vor der Umlagerung in die horizontale Rückenlage wurde die Zufuhr der Anästhetika abrupt unterbrochen und folgende Aufwachzeiten erfaßt: Eintritt Spontanatmung (VT〉4 ml/kg), Extubation, Augenöffnen, richtiges Benennen von Namen und Geburtsdatum und der Analgetikabedarf der ersten 2 postoperativen Stunden im Aufwachraum. Ergebnisse: Die Patienten der D/L-Gruppe reagierten auf den Intubationsreiz und die Hautinzision mit signifikanten Blutdruckanstiegen und zeigten signifikant höhere Herzfrequenzwerte, während ansonsten die hämodynamischen Parameter während des Narkoseverlaufs vergleichbar waren. Die Patienten der P/R-Gruppe erreichten signifikant früher eine stabile Spontanatmung (3,2 vs. 6,4 min), konnten früher extubiert werden (3,8 vs. 9,5 min), öffneten früher die Augen (3,0 vs. 11,5 min) und waren eher in der Lage, ihren Namen und Geburtsdatum zu benennen (4,8 vs. 14,3 min), wiesen aber auch signifikant häufiger Muskelzittern auf. Keine signifikanten Unterschiede fanden sich im Analgetikabedarf sowie in der Inzidenz von Übelkeit und Erbrechen. Schlußfolgerung: Die Patienten erwachen aus der TIVA mit Propofol/Remifentanil schneller als aus der Desfluran/N2O-Narkose und erreichen schneller ein höheres Vigilanzniveau, wobei die geringe Intensität postoperativer Wundschmerzen nach Bandscheibenoperationen kein aufwendiges Konzept zur postoperativen Analgesie erfordert.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-0662
    Keywords: Antarctica ; Palmer ; Marsh ; Mawson ; aerosol particles ; biogeochemical cycles ; sulfate ; nitrate ; methanesulfonate ; lead-210 ; beryllium-7 ; sea-salt ; ammonium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract High volume bulk aerosol samples were collected continuously at three Antarctic sites: Mawson (67.60° S, 62.50° E) from 20 February 1987 to 6 January 1992; Palmer Station (64.77° S, 64.06° W) from 3 April 1990 to 15 June 1991; and Marsh (62.18° S, 58.30° W) from 28 March 1990, to 1 May 1991. All samples were analyzed for Na+, SO 4 2− , NO 3 − , methanesulfonate (MSA), NH 4 + ,210Pb, and7Be. At Mawson for which we have a multiple year data set, the annual mean concentration of each species sometimes vary significantly from one year to the next: Na+, 68–151 ng m−3; NO 3 − , 25–30 ng m−3; nss SO 4 2− , 81–97 ng m−3; MSA, 19–28 ng m−3; NH 4 + , 16–21 ng m−3;210Pb, 0.75–0.86 fCi m−3. Results from multiple variable regression of non-sea-salt (nss) SO 4 2− with MSA and NO 3 − as the independent variables indicates that, at Mawson, the nss SO 4 2− /MSA ratio resulting from the oxidation of dimethylsulfide (DMS) is 2.80±0.13, about 13% lower than our earlier estimate (3.22) that was based on 2.5 years of data. A similar analysis indicates that the ratio at Palmer is about 40% lower, 1.71±0.10, and more comparable to previous results over the southern oceans. These results when combined with previously published data suggest that the differences in the ratio may reflect a more rapid loss of MSA relative to nss SO 4 2− during transport over Antarctica from the oceanic source region. The mean210Pb concentrations at Palmer and Marsh and the mean NO 3 − concentration at Palmer are about a factor of two lower than those at Mawson. The210Pb distributions are consistent with a210Pb minimum in the marine boundary layer in the region of 40°–60° S. These features and the similar seasonalities of NO 3 − and210Pb at Mawson support the conclusion that the primary source regions for NO 3 − are continental. In contrast, the mean concentrations of MSA, nss SO 4 2− , and NH 4 + at Palmer are all higher than those at Mawson: MSA by a factor of 2; nss SO 4 2− by 10%; and NH 4 + by more than 50%. However, the factor differences exhibit substantial seasonal variability; the largest differences generally occur during the austral summer when the concentrations of most of the species are highest. NH 4 + /(nss SO 4 2− +MSA) equivalent ratios indicate that NH3 neutralizes about 60% of the sulfur acids during December at both Mawson and Palmer, but only about 30% at Mawson during February and March.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-0662
    Keywords: Antarctica ; aerosol particles ; ice ; biogeochemical cycles ; sulfate ; nitrate ; methanesulfonate ; lcad-210 ; boryllium-7 ; sea-salt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract High volume aerosol samples were collected continuously at Mawson, Antarctica (67°36'S, 62°30'E), from February 1987 through October 1989. All samples were analyzed for Na+, Cl-, SO4 =, NO3 -, methanesulfonate (MSA), NH4 +,7Be, and210Pb. The annual mean concentrations of many of the species are very low, substantially lower than even those over the relatively pristine regions of the tropical and subtropical South Pacific. The concentrations at Mawson are comparable both in magnitude and in seasonality to those which have been measured in long term studies at the South Pole and at the coastal German Antarctic research station, Georg von Neumayer (GvN). This comparability suggests that the aerosol composition may be relatively uniform over a broad sector of the Antarctic. The concentrations of most of the species exhibit very strong and sharply-defined seasonal cycles. MSA, non-sea-salt (nss) SO4 = and NH4 + all exhibit similar cycles, with maxima during the austral summer (December through February) being more than an order of magnitude higher than the winter minima. The limited7Be data appears to exhibit a similar cycle. Although nitrate and210Pb also exhibit relatively high concentrations during the austral summer, their cycles are far more complex than those of the previous species with indications of multiple peaks. As expected, the concentration of sea-salt (as indicated by Na+ and Cl-) peaks during the winter. The results from multiple variable regression analyses indicate that the dominant source of nss SO4 = is the oxidation of dimethylsulfide (DMS) which produces MSA and nss SO4 = in a ratio of about 0.31 (about five times higher than that over the tropical and subtropical oceans). However, a very significant fraction (about 25%) of the nss SO4 = is associated with NO3 -, The seasonal cycle of NO3 - is similar to that of210Pb and distinctly different from that of7Be and MSA. These results indicate that the major source of NO3 - over Antarctica is probably continental as opposed to stratospheric or marine biogenic.
    Type of Medium: Electronic Resource
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