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Titolo:
ELECTROENCEPHALOGRAPHIC DEMONSTRATION OF CENTRAL-NERVOUS-SYSTEM EFFECTS OF DIFFERENT PREMEDICATION REGIMENS
Autore:
ENTHOLZNER E; SCHNECK HJ; HARGASSER S; HIPP R; TEMPEL G;
Indirizzi:
TECHUNIV MUNCHEN,KLINIKUM RECHTS ISAR,INST ANAESTHESIOL,ISMANINGERSTR22 D-81675 MUNICH GERMANY
Titolo Testata:
Anasthesist
fascicolo: 7, volume: 43, anno: 1994,
pagine: 431 - 440
SICI:
0003-2417(1994)43:7<431:EDOCE>2.0.ZU;2-5
Fonte:
ISI
Lingua:
GER
Soggetto:
MIDAZOLAM KINETICS; GASTRIC CONTENTS; SURGERY; MEPERIDINE; SUFENTANIL; MORBIDITY; SEDATION; FENTANYL; VOLUME; FLUID;
Keywords:
PREMEDICATION; ATROPINE; PROMETHAZINE; PETHIDINE; MEPERIDINE; NORDAZEPAM; DESMETHYLDIAZEPAM; MIDAZOLAM; EEG; PHARMACO-EEG; ELECTROENCEPHALOMETRY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
47
Recensione:
Indirizzi per estratti:
Citazione:
E. Entholzner et al., "ELECTROENCEPHALOGRAPHIC DEMONSTRATION OF CENTRAL-NERVOUS-SYSTEM EFFECTS OF DIFFERENT PREMEDICATION REGIMENS", Anasthesist, 43(7), 1994, pp. 431-440

Abstract

Introduction: For many years, the main goal of premedication was prevention of the dangerous side effects sometimes encountered in anesthetics with anticholinergics, antiemetic antihistaminics, and opioids. Because the rules were always preoperative fasting, premedication was administered i.m. Thus, the onset of action was within 15-30 min from administration. In recent years, with the introduction of newer anesthetics with fewer side effects, anxiolysis became the main aim in premedication. Moreover, the oral route became popular since it obviously didnot increase the acidity or volume of the gastric content. However, the uptake and thus onset of action of orally administered drugs may take longer and can differ considerably between individual patients. Therefore, the optimum interval between administration and induction of anesthesia remains controversial. The present study was carried out to examine the time course of drug action and the effects of different premedication regimens on the electroencephalogram (EEG). Patients and methods: After obtaining informed consent, in 38 unselected adult patients (ASA I and II, < 65 years) scheduled for elective surgery, the EEGwas recorded continuously before and after premedication. The patients were randomly assigned to four groups: M: midazolam, 0.2 mg/kg BW orally; N: nordazepam, 0.2 mg/kg BW orally; AP: atropine, 0.5 mg, plus promethazine, 50 mg i.m.; APP: atropine, 0.5 mg, plus promethazine, 50 mg, plus pethidine, 0.7 mg/kg BW i.m. The EEG was recorded for a reference period of 10 min before and a study period of 30 min after premedication. Automated EEG processing was performed with CATEEM(R) (computer-aided topographical electroencephalometry). Surface electrodes wereplaced according to the 10-20 system. Date were collected via an amplifier (resistance 10 MOMEGA) and a digitalization unit (filter 0.2-35 Hz, sampling rate 512 Hz, 12 bit A/D convertor). The original EEG signals were used in an interpolation algorythm to produce an additional 82 virtual recording points, allowing for high topographical resolution. After spectral analysis (fast Fourier transformation), the differentfrequency ranges of the EEG power spectrum are displayed in differentcolors. The screen displays the on-line map with color-based topographical power distribution. In order to achieve a pharmacodynamic time profile, the study period was subdivided into three periods of 10 min each. For clinical evaluation of vigilance, a 6-grade scoring system was used 1 = awake, 6 = not arousable). Results: All data are presented with respect to reference period. The power density of each frequency range for each electrode is integrated over the selected period and mean values are shown. Changes in power density with time are expressed as percentage change from reference period. Biometrical data showed nosignificant differences between groups. The median vigilance score 30min after premedication (end of study period) was 4 in groups M, AP, and APP, and 3 in group N. In both benzodiazepine groups, a distinct increase in power density was found in the beta-bands, while in groups AP and APP the increase was most pronounced in the delta and theta bands. In group M, there was a linear increase in beta1 power up to 310 %, while in the beta2 range there was a 170% maximum within the second period of 10 min. In group N, there was a similar course with a lower increase in beta1 (220%) and beta2 (130%). Increases in both beta-bands were most pronounced with frontal electrodes. While group M showed an increase in delta power (150%), together with moderate suppression in alpha (alpha1 50%, alpha2 40%), nordazepam caused only a slight increase in delta (124%) and a distinct increase in alpha2, to 150%, predominantly in the frontal areas. Group APP showed a linear increase in both delta up to 210% and theta power to 190%. Maximum increases in delta (170%) and theta (140%) in group AP, however, were less pronounced and occurred in the second period. In both groups there was suppression in alpha1 (AP: 20-40%, APP: 40-60%) and alpha2 (AP: 30-60%, APP: 40-60%). Conclusion: Our results indicate that premedication with oral benzodiazepines results in beta-activation, corresponding to the anxiolytic effect, while the degree of sedation as expressed by delta and theta bands may depend on the specific drug and dosage. The lower vigilance scores in group N may suggest a lower degree of sedative effect or too low a dosage. When benzodiazepines with fast uptake kinetics are administered orally, pharmacodynamic EEG effects may occur as soon as 30 min or less after premedication.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/07/20 alle ore 04:21:41