Bispectral Index Monitoring Allows Faster Emergence and Improved Recovery from Propofol, Alfentanil, and Nitrous Oxide Anesthesia

Background: The bispectral index (BIS), a parameter derived from the electroencephalograph (EEG), has been shown to correlate with increasing sedation and loss of consciousness. This study determined whether addition of BIS monitoring to standard anesthetic practice results in improvements in the conduct of anesthesia or in patient outcomes.

Methods: Three hundred two patients receiving a propofol-alfentanil-nitrous oxide anesthetic were studied at four institutions. Thirty-four patients were initially enrolled to determine preexisting anesthetic practice and patient outcomes at each institution. Subsequent patients were randomized to either standard clinical practice (SP group), or standard practice plus BIS monitoring (BIS group). In all patients, the anesthesiologist attempted to provide a stable anesthetic with the fastest possible recovery. BIS was recorded for all patients, but viewed only in the BIS group. In the BIS group, propofol infusions were adjusted to achieve a target BIS between 45-60, increasing to 60-75 during the final 15 min of the case. In the SP group, propofol dose adjustments were made based only on standard clinical signs. Drug use, intraoperative responses, and patient recovery parameters were recorded.

Results: Demographics were similar between groups. Compared with the SP group, patients in the BIS group required lower normalized propofol infusion rates (134 vs. 116 micro gram [center dot] kg sup -1 [center dot] min sup -1; P < 0.001), were extubated sooner (11.22 vs. 7.25 min; P < 0.003), had a higher percentage of patients oriented on arrival to PACU (43% vs. 23%; P < 0.02), had better postanesthesia care unit (PACU) nursing assessments (P < 0.001), and became eligible for discharge sooner (37.77 vs. 31.70 min; P < 0.04). There was no significant difference in the incidence of intraoperative responses between the groups.     

Spectral Entropy Monitoring Is Associated with Reduced Propofol Use and Faster Emergence in Propofol-Nitrous Oxide-Alfentanil Anesthesia

Background: This multicenter study evaluated the effect of a new depth of anesthesia-monitoring device based on time-frequency-balanced spectral entropy of electroencephalogram monitoring (GE Healthcare Finland, Helsinki, Finland) on consumption of anesthetic drugs and recovery times after anesthesia.

Methods: The study was a prospective, randomized, single-blind study performed in six hospitals in Finland, Sweden, and Norway. After institutional review board approval and written informed consent from each patient, the patients were randomly allocated to anesthesia with entropy values either shown (entropy group) or not shown (control group). Anesthesia was maintained with propofol, nitrous oxide, and alfentanil. In the entropy group, propofol was given to keep the state entropy value between 45 and 65, and alfentanil was given to keep the state entropy-response entropy difference below 10 units and heart rate and blood pressure within +/-20% of the baseline values. The control group patients were anesthetized to keep heart rate and blood pressure within +/-20% of the baseline values. Statistical methods included Mann-Whitney U test and unpaired t tests.

Results: A total of 368 patients were studied. In the entropy group, entropy values were higher during the whole operation and especially during the last 15 min (P < 0.001). Consequently, propofol consumption was smaller in the entropy group during the whole anesthesia period (P < 0.001) and especially during the last 15 min (P < 0.001). This shortened the time delay in the early recovery parameters in the entropy group.     

Narcotrend监测在临床麻醉中的应用及研究进展

随着人们对术中维持适宜麻醉深度重要性及术中知晓危害性认识的增加。新型脑电监测系统麻醉／意识深度监测仪被越来越广泛地应用于临床和科研．大曩研究结果证实了它的有效性。现就Narcotrend麻醉深度监测的临床应用及其研究进展作一综述。     

Narcotrend监测下硬膜外阻滞复合全麻在老年病人腹部手术中的应用

目的比较Narcotrend监测下硬膜外阻滞复合全麻和单纯全麻用于老年病人腹部手术的临床效果,探讨老年腹部手术病人更安全合理的麻醉方式。方法 40例ASAⅡ～Ⅲ择期行腹部手术的老年病人,随机分为硬膜外阻滞复合全麻组(EGA)和单纯全麻组(GA),每组20例。两组全麻诱导用药为舒芬太尼0.4μg/kg、顺苯磺阿曲库铵0.15 mg/kg、依托咪酯0.2 mg/kg,气管插管后微泵持续输注丙泊酚、瑞芬太尼及间断静注顺苯磺阿曲库铵维持麻醉,术中行Narcotrend监测并使Narcotrend分级(NTS)维持在D0～D2之间。EGA组全麻诱导前先行硬膜外穿刺置管,注入试验剂量1.3%利多卡因3 ml,气管插管后硬膜外追加1.3%利多卡因6～8 ml,再以0.375%罗哌卡因5～8 ml/次维持硬膜外阻滞。术中监测血流动力学变化,术毕记录两组病人全麻维持用药量和病人睁眼时间、拔管时间及定位功能恢复时间等。结果 EGA组术中收缩压低于GA组(P<0.05);术中麻醉用药比较,EGA组丙泊酚及顺苯磺阿曲库铵用量少于GA组(P<0.05),EGA组瑞芬太尼用量明显少于GA组(P<0.01);恢复时间比较,EGA组病人睁眼时间、拔管时间、定位功能恢复时间均明显短于GA组(P<0.01);两组病人均无术中知晓发生。结论硬膜外阻滞复合全麻用于老年病人腹部手术血流动力学稳定,全麻药用量减少,病人恢复较快,是一种安全可行的麻醉方法,同时进行麻醉深度监测,有利于预防术中知晓。     

Development and Evaluation of a Graphical Anesthesia Drug Display

Background: Usable real-time displays of intravenous anesthetic concentrations and effects could significantly enhance intraoperative clinical decision-making. Pharmacokinetic models are available to estimate past, present, and future drug effect-site concentrations, and pharmacodynamic models are available to predict the drug's associated physiologic effects.

Methods: An interdisciplinary research team (bioengineering, architecture, anesthesiology, computer engineering, and cognitive psychology) developed a graphic display that presents the real-time effect-site concentrations, normalized to the drugs' EC95, of intravenous drugs. Graphical metaphors were created to show the drugs' pharmacodynamics. To evaluate the effect of the display on the management of total intravenous anesthesia, 15 anesthesiologists participated in a computer-based simulation study. The participants cared for patients during two experimental conditions: with and without the drug display.

Results: With the drug display, clinicians administered more bolus doses of remifentanil during anesthesia maintenance. There was a significantly lower variation in the predicted effect-site concentrations for remifentanil and propofol, and effect-site concentrations were maintained closer to the drugs' EC95. There was no significant difference in the simulated patient heart rate and blood pressure with respect to experimental condition. The perceived performance for the participants was increased with the drug display, whereas mental demand, effort, and frustration level were reduced. In a postsimulation questionnaire, participants rated the display to be a useful addition to anesthesia monitoring.     

Independent Predictors of Delay in Emergence From General Anesthesia

Some patients with intellectual disabilities spend longer than others in emergence from ambulatory general anesthesia for dental treatment. Although antiepileptic drugs and anesthetics might be involved, an independent predictor for delay of the emergence remains unclear. Thus, a purpose of this study is to identify independent factors affecting the delay of emergence from general anesthesia. This was a retrospective cohort study in dental patients with intellectual disabilities. Patients in need of sedative premedication were removed from participants. The outcome was time until emergence from general anesthesia. Stepwise multivariate regression analysis was used to extract independent factors affecting the outcome. Antiepileptic drugs and anesthetic parameters were included as predictor variables. The study included 102 cases. Clobazam, clonazepam, and phenobarbital were shown to be independent determinants of emergence time. Parameters relating to anesthetics, patients'' backgrounds, and dental treatment were not independent factors. Delay in emergence time in ambulatory general anesthesia is likely to be related to the antiepileptic drugs of benzodiazepine or barbiturates in patients with intellectual disability.Key Words: Day case, Propofol, Remifentanil, Anticonvulsants, Benzodiazepines, Barbituric acidAmbulatory general anesthesia is useful for dental treatment of patients with severe intellectual disabilities because it is hard for them to cooperate with dental treatment and to stay in the hospital.^1–3 Because controlling the recovery state is important in managing ambulatory general anesthesia, we perform total intravenous anesthesia consisting mainly of propofol and remifentanil, which allows a quick and comfortable recovery.^4–7 Midazolam, a short-acting benzodiazepine injection, was shown to be a clear determinant of delayed recovery from general anesthesia in our previous study,⁸ so we ceased using midazolam injection in ambulatory general anesthesia in our facility. Nevertheless, some patients still spent longer than others in emergence and/or recovery from general anesthesia. Therefore, other independent factors were suspected to affect the recovery state in patients with intellectual disabilities.Patients with intellectual disabilities use antiepileptic drugs (AEDs) at a higher rate; these are known to interact with other drugs, mainly by affecting drug metabolism, such as CYP and/or uridine diphosphate-glucuronosyl-transferase (UGT).^9–13 Because AEDs have a sedative effect, they are considered to enhance the clinical effects of anesthetics. In addition, patients with epilepsy are often controlled with multidrug therapy, and several anesthetics can be used for general anesthesia. It is therefore difficult to identify independent factors affecting recovery from general anesthesia when a patient with epilepsy has a delayed emergence from general anesthesia. We therefore sought to identify factors affecting emergence from general anesthesia. We used multivariate analysis in a retrospective cohort study, in which each AED was included as a predictor variable, in addition to anesthetic parameters.     

Development and Psychometric Evaluation of the Pediatric Anesthesia Emergence Delirium Scale

Background: Emergence delirium has been investigated in several clinical trials. However, no reliable and valid rating scale exists to measure this phenomenon in children. Therefore, the authors developed and evaluated the Pediatric Anesthesia Emergence Delirium (PAED) scale to measure emergence delirium in children.

Methods: A list of scale items that were statements describing the emergence behavior of children was compiled, and the items were evaluated for content validity and statistical significance. Items that satisfied these evaluations comprised the PAED scale. Each item was scored from 1 to 4 (with reverse scoring where applicable), and the scores were summed to obtain a total scale score. The degree of emergence delirium varied directly with the total score. Fifty children were enrolled to determine the reliability and validity of the PAED scale. Scale validity was evaluated using five hypotheses: The PAED scale scores correlated negatively with age and time to awakening and positively with clinical judgment scores and Post Hospital Behavior Questionnaire scores, and were greater after sevoflurane than after halo-thane. The sensitivity of the scale was also determined.

Results: Five of 27 items that satisfied the content validity and statistical analysis became the PAED scale: (1) The child makes eye contact with the caregiver, (2) the child's actions are purposeful, (3) the child is aware of his/her surroundings, (4) the child is restless, and (5) the child is inconsolable. The internal consistency of the PAED scale was 0.89, and the reliability was 0.84 (95% confidence interval, 0.76-0.90). Three hypotheses supported the validity of the scale: The scores correlated negatively with age (r = -0.31, P <0.04) and time to awakening (r = -0.5, P <0.001) and were greater after sevoflurane anesthesia than halothane (P <0.008). The sensitivity was 0.64.     

Applications of Drug Anesthesia in Control Chronic Pain

Surgery is one of the major causes of chronic pain in patients that have undergone any kind of surgeries. These complain are not only associated with major surgeries; even common minor surgeries like hernia repair have a significant risk of chronic pain. The development of chronic postsurgical pain (CPSP) depends on the type of surgical technique used. Furthermore, changes in the central nervous system have been associated with the development of persistent and chronic pain after surgical trauma and nerve injury. Anesthesia agents that block the mechanisms stimulating the process of central sensitization may be efficient in reducing the incidence of CPSP and finally psychosocial factors have been reported to be an important factor in the progression of chronic pain and as such should be addressed as part of perioperative care. The purpose of this mini-review is to give a comprehensive summary of the application of anesthesia drugs to reduce or control chronic pain during or after surgery.     

Comparative Evaluation of the Datex-Ohmeda S/5 Entropy Module and the Bispectral Index® Monitor during Propofol-Remifentanil Anesthesia

Background: Different analytical concepts were introduced to quantify the changes of the electroencephalogram. The Datex-Ohmeda S/5 Entropy Module (Datex-Ohmeda Division, Instrumentarium Corp., Helsinki, Finland) was the first commercial monitor based on the entropy generating two indices, the state entropy (SE) and the response entropy (RE). The aim of the current study was to compare the accuracy of SE and RE with the Bispectral Index(R) monitor (BIS(R); Aspect Medical Systems, Newton, MA) during propofol-remifentanil anesthesia.

Methods: The authors investigated 20 female patients during minor gynecologic surgery. SE, RE, BIS, mean arterial blood pressure, heart rate, and sedation level were recorded every 20 s during stepwise increase (target-controlled infusion, 0.5 [mu]g/ml) of propofol until the patients lost response. Five minutes after loss of response, remifentanil infusion (0.4 [mu]g [middle dot] kg-1 [middle dot] min-1) was started. Spearman correlation coefficient and prediction probability were calculated for sedation levels with SE, RE, BIS, mean arterial blood pressure, and heart rate. The ability of the investigated parameters to distinguish between the anesthesia steps awake versus loss of response, awake versus anesthesia, anesthesia versus first reaction, and anesthesia versus extubation was analyzed with the prediction probability.

Results: SE correlates best with sedation levels, but no significant differences of the prediction probability values among SE, RE, and BIS were found. The prediction probability for all investigated steps of anesthesia did not show significant differences among SE, RE, and BIS. SE, RE, and BIS were superior to mean arterial blood pressure and heart rate.     

Effect of Cranial Surgery and Brain Tumor Size on Emergence from Anesthesia

Background: Knowing which neurosurgical patients are at risk for delayed awakening may lead to better utilization of intensive care resources and avoid the risk and cost of pharmacologic reversal and diagnostic tests.

Methods: The authors compared anesthetic emergence from complex spinal surgery (spine; n = 47) with that from craniotomy for supratentorial nonfrontal (n = 22), frontal (n = 34), or posterior fossa tumor (n = 28). A further comparison involved patients with small versus large (diameter > 30 mm, mass effect) tumors. The standardized anesthetic regimen consisted of induction with 2-4 mg/kg sup -1 thiopental and 1-2 micro gram/kg sup -1 sufentanil, followed by maintenance with nitrous oxide, 0.2-0.5 micro gram *symbol* kg sup -1 *symbol* h sup -1 sufentanil and less or equal to 0.5% isoflurane. Sufentanil administration was terminated on dural or spinal muscle closure, isoflurane during skin closure, and nitrous oxide during dressing application. After discontinuing nitrous oxide, a minineurologic examination was performed every 15 min for 1 h, then hourly for 4 h and at 24 h.

Results: Craniotomy patients performed less well than spinal surgery patients on the minineurologic examination 15 and 30 min after discontinuing nitrous oxide. At 15 min, fewer patients with large (vs. small) tumors were oriented to time (58% vs. 87%; P < 0.01) or place (67% vs. 90%; P < 0.01). Forty-two percent of patients with large tumors still had an abnormal minineurologic examination score versus 15% of patients with small tumors. At 30 min, these values were 28% and 8%, respectively (P < 0.05). Seventy-one percent of patients with large tumors were oriented to time compared to 97% for small lesions (P <0.01). Emergence from anesthesia was similar for spinal surgery patients and patients with small brain tumors.     

异氟醚全麻深度的多指标判断

由于箭毒和新的麻醉技术的应用，乙醚麻醉分期已不再适用，急需寻找新的方法判断麻醉深度。本研究通过观察６０例在模拟刺激和手术刺激下异氟醚０．４－１．６ＭＡＣ呼气末浓度与脑电频率和波幅、额肌电波幅、手指动脉收缩和舒张压，肱动脉收缩和舒张压，批端容积波波幅，心率，诱发性食管下段收缩性，吸呼末氧浓度差，呼末二氧化碳浓度１２例指标的相关性分析，对上述各指标在全麻深度判断中的作用进一步评价。     

血肿内麻醉后抽吸法在骨折整复中的应用

对四肢创伤闭合性骨折2454例采用一种血肿内抽吸式局麻方法施行手法整复的经验进行总结。其方法为:在骨折断端注入局麻药10～20ml,待1～2min麻醉起效后,先将麻药和骨折断端血肿之混合液抽出,继之再行手法复位。经临床应用2454例,总的满意率100％,优良率达91.5％,无一例并发症发生。作者认为该法具有如下优点:(1)麻醉效果仍满意;(2)明显减少麻醉药物的毒副作用;(3)血肿内麻药混合液抽吸后,有利于手法整复中的手摸心会,便于骨折整复;(4)局部张力减小,减少外固定早期骨筋膜间室综合征的发生机会;(5)使外固定后肢体肿胀消退,周径缩小不致过大,增强骨折固定的稳定性。