Awareness during general anesthesia occurs in approximately 0.1–0.2% of cases; nevertheless, particular attention is required because it can lead to critical complications including insomnia, depression, anxiety, and post-traumatic stress disorder. To prevent these complications, bispectral index (BIS) and end-tidal anesthetic gas (ETAG) concentration monitoring are commonly used to examine patient consciousness during surgery. In the present case, an 80-year-old man was scheduled for total gastrectomy. Anesthesia was maintained using desflurane 4.0–5.0% vol, oxygen, and nitrous oxide. The authors simultaneously monitored BIS, which was maintained between 37 and 43, and ETAG, which was maintained between 0.9 and 1.2 minimum alveolar concentration (MAC). After the operation, however, the authors were surprised to learn that the patient complained of awareness during anesthesia. Although BIS and ETAG concentration monitoring are useful in preventing awareness during anesthesia, they cannot be completely trusted. Even though BIS was maintained at approximately 40 and ETAG at 0.7–1.3 MAC, awareness during anesthesia occurred.
Aged, 80 and over ; Anesthesia ; Anesthesia, General ; Anxiety ; Consciousness ; Consciousness Monitors ; Depression ; Gastrectomy ; Humans ; Intraoperative Awareness ; Nitrous Oxide ; Oxygen ; Sleep Initiation and Maintenance Disorders ; Stress Disorders, Post-Traumatic

BACKGROUND: Phase-lag entropy (PLE) was recently described as a measurement of temporal pattern diversity in the phase relationship between two electroencephalographic signals from prefrontal and frontal montages. This study was performed to evaluate the performance of PLE for assessing the depth of sedation. METHODS: Thirty adult patients undergoing upper limb surgery with a brachial plexus block were administered propofol by target-controlled infusion. The depth of sedation was assessed using the Observer's Assessment of Alertness/Sedation (OAA/S) scale. The effect-site concentration (Ce) of propofol was initially started at 0.5 μg/ml and was increased in increments of 0.2 μg/ml until an OAA/S score of 1 was reached. Three minutes after the target Ce was reached, the PLE, bispectral index (BIS), and level of sedation were assessed. Correlations between the OAA/S score and PLE or BIS were determined. The prediction probabilities (P(k)) of PLE and BIS were also analyzed. RESULTS: The PLE values were closely correlated with the OAA/S scores (Spearman's Rho = 0.755; P < 0.001) to an extent comparable with the correlation between the BIS and OAA/S score (Spearman's Rho = 0.788; P < 0.001). The P(k) values of PLE and BIS were 0.731 and 0.718, respectively. CONCLUSIONS: PLE is a new and reliable consciousness monitoring system for assessing the depth of sedation induced by propofol, which is comparable with the BIS.
Adult ; Brachial Plexus Block ; Consciousness Monitors ; Electroencephalography ; Entropy ; Humans ; Propofol ; Upper Extremity

BACKGROUND: Most depth of anesthesia (DOA) monitors rely on the temporal characteristics of a single-channel electroencephalogram (EEG) and cannot provide spatial or connectivity information. Phase lag entropy (PLE) reflects DOA by calculating diverse connectivity from temporal patterns of phase relationships. The aim of this study was to compare the performance of PLE and bispectral index (BIS) monitors for assessing DOA during anesthesia induction, nerve integrity monitoring (NIM), and anesthesia emergence. METHODS: Thirty-five patients undergoing elective thyroid surgery with recurrent laryngeal nerve NIM received propofol and remifentanil via target-controlled infusion. After applying PLE and BIS monitors, propofol infusion was initiated at a calculated effect site concentration (Ce) of 2 µg/mL and then increased in 1-µg/mL Ce increments. After propofol Ce reached 5 μg/mL, a remifentanil infusion was begun, and anesthesia induction was considered complete. During NIM, PLE and BIS values were compared at a specific time points from platysma muscle exposure to subcutaneous tissue closure. PLE and BIS values were recorded continuously from preanesthetic state to full recovery of orientation; bias and limits of agreement between monitors were calculated. RESULTS: PLE and BIS values decreased progressively with increasing propofol Ce during anesthetic induction and increased by stages during emergence. The prediction probabilities of PLE and BIS for detecting propofol Ce changes were 0.750 and 0.756, respectively, during induction and 0.749 and 0.746, respectively, during emergence. No aberrant PLE or BIS values occurred during NIM. Correlation coefficients for BIS and PLE were 0.98 and 0.92 during induction and emergence, respectively. PLE values were significantly higher than BIS values at full recovery of orientation. Estimated bias between monitors was −4.16 ± 8.7, and 95% limits of agreement were −21.21 to 12.89. CONCLUSION: PLE is a reasonable alternative to BIS for evaluating consciousness and DOA during general anesthesia and during NIM. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0003490
Anesthesia ; Anesthesia, General ; Bias (Epidemiology) ; Consciousness ; Consciousness Monitors ; Electroencephalography ; Entropy ; Humans ; Information Services ; Propofol ; Recurrent Laryngeal Nerve ; Subcutaneous Tissue ; Superficial Musculoaponeurotic System ; Thyroid Gland

BACKGROUND: This prospective study aimed to determine whether the bispectral index (BIS) is a valid objective tool for differentiating adequate from inadequate deep sedation in spontaneously breathing children with cerebral palsy (CP).METHODS: Propofol was titrated to increase the level of sedation with a continuous infusion of remifentanil at a rate of 0.05 μg/kg/min while maintaining spontaneous ventilation in 22 children with spastic CP, aged 3–18 years. The depth of sedation was assessed using the University of Michigan Sedation Scale (UMSS) and the Modified Observer’s Assessment of Alertness and Sedation (MOAAS) scale. Receiver operating characteristic curve analysis was performed to determine the cutoff BIS values for deep sedation, defined as a UMSS score of 3–4 and a MOAAS score of 0–1.RESULTS: The BIS values significantly changed with the increase in the level of sedation across both the UMSS and MOAAS scores (P < 0.001). The BIS values correlated with the UMSS (r = −0.795, P < 0.001) and MOAAS (r = 0.815, P < 0.001) scores. The cutoff BIS value to detect adequate deep sedation in children with CP was 61.5 (UMSS score: sensitivity 0.860, specificity 0.814; MOAAS score: sensitivity 0.794, specificity 0.811).CONCLUSIONS: The BIS value strongly correlates with the clinical sedation scales, such as the UMSS and MOAAS, during deep sedation in children with CP. Therefore, BIS monitoring can be used as a valid tool for assessing the level of propofol sedation in spontaneously breathing children with CP undergoing a botulinum toxin injection.
Botulinum Toxins ; Cerebral Palsy ; Child ; Consciousness Monitors ; Deep Sedation ; Humans ; Michigan ; Muscle Spasticity ; Propofol ; Prospective Studies ; Respiration ; ROC Curve ; Sensitivity and Specificity ; Ventilation ; Weights and Measures

BACKGROUND: The bispectral index (BIS) is a valuable indicator for measuring sedation levels and patient consciousness. Recent reports have highlighted its clinical value as an indicator for anesthesia-related cerebral hypoperfusion and ischemic brain damage. CASE REPORT: A 55-year-old female patient underwent right breast conservation surgery during general anesthesia. During surgery, the patient experienced abrupt bradycardia (heart rate of 36 bpm) without hypotension. During bradycardia, her BIS was severely reduced from 45 to 20 along with elvated suppression ratio (50). After injection of 0.5mg of atropine, her BIS level was recovered, her heart rate was increased, and her suppression ratio was decreased. CONCLUSION: The patient recovered from anesthesia without showing any signs of neurological sequelae based on BIS level monitoring.
Anesthesia ; Anesthesia, General ; Atropine ; Bradycardia ; Brain ; Breast ; Consciousness ; Consciousness Monitors ; Female ; Heart Rate ; Humans ; Hypotension ; Mastectomy, Segmental ; Middle Aged

BACKGROUND: Conscious sedation has been widely utilized in plastic surgery. However, inadequate research has been published evaluating adequate drug dosage and depth of sedation. In clinical practice, sedation is often inadequate or accompanied by complications when sedatives are administered according to body weight alone. The purpose of this study was to identify variables influencing the depth of sedation during conscious sedation for plastic surgery. METHODS: This prospective study evaluated 97 patients who underwent plastic surgical procedures under conscious sedation. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and glucose levels were measured. Midazolam and ketamine were administered intravenously according to a preset protocol. Bispectral index (BIS) recordings were obtained to evaluate the depth of sedation 4, 10, 15, and 20 minutes after midazolam administration. Associations between variables and the BIS were assessed using multiple regression analysis. RESULTS: Alcohol intake and female sex were positively associated with the mean BIS (P<0.01). Age was negatively associated with the mean BIS (P<0.01). Body mass index (P=0.263), creatinine clearance (P=0.832), smoking history (P=0.398), glucose (P=0.718), AST (P=0.729), and ALT (P=0.423) were not associated with the BIS. CONCLUSIONS: Older patients tended to have a greater depth of sedation, whereas females and patients with greater alcohol intake had a shallower depth of sedation. Thus, precise dose adjustments of sedatives, accounting for not only weight but also age, sex, and alcohol consumption, are required to achieve safe, effective, and predictable conscious sedation.
Alanine Transaminase ; Alcohol Drinking ; Aspartate Aminotransferases ; Body Mass Index ; Body Weight ; Conscious Sedation* ; Consciousness Monitors ; Creatinine ; Deep Sedation ; Female ; Glucose ; Humans ; Hypnotics and Sedatives ; Ketamine ; Midazolam ; Plastics* ; Prospective Studies* ; Smoke ; Smoking ; Surgery, Plastic*

Regional anesthesia is mostly used in operations on the lower abdomen or lower extremities in elderly patients. It shows nearly no difference in long-term outcomes compared to general anesthesia, but it is used more often because of the several advantages. However, during the regional anesthetic procedures, the patient must cooperate and has to be lateral decubitus position without physical movement. Therefore, in the case of the patients who are not cooperated, it may be not easy to perform regional anesthesia. In this study, we present 3 case reports that regional anesthesia after sedation is performed in un-cooperated patients. Regional anesthesia after sedation may be a good method to improve outcomes in un-cooperated elderly patients.
Abdomen ; Aged* ; Anesthesia, Conduction ; Anesthesia, General ; Anesthesia, Spinal* ; Consciousness Monitors ; Humans ; Lower Extremity ; Methods

BACKGROUND: For many drugs, dosing scalars such as ideal body weight (IBW) and lean body mass are recommended over the use of total body weight (TBW) during weight-based dose calculations. Doses based on TBW are frequently used, and this may cause under- or over-dosing. Because dexmedetomidine (DEX) overdosing could increase the incidence of side effects, and spinal anesthesia may increase sensitivity to a sedative agent, determining an appropriate dose is critical. METHODS: Eighty patients were randomly divided into 2 groups, the IBW and TBW groups. Patients received a loading dose of DEX 1 µg/kg IBW or TBW for 10 min, followed by a continuous infusion at 0.5 µg/kg/h IBW or TBW after the induction of spinal anesthesia. The patients' vital signs, bispectral index (BIS), peripheral capillary oxygen saturation, time to reach a BIS of 80, airway obstruction score, and coughing were monitored and recorded at 0, 10, 30, and 50 min after the start of the loading dose injection. RESULTS: The changes in BIS, airway obstruction score, the incidence of side effects, and time to reach a BIS of 80 did not show statistically significant differences between the two groups. However, airway obstruction and/or coughing occurred in both groups, and the average BIS in both groups was lower than the target BIS of 60-80 at 30 and 50 min. CONCLUSIONS: A loading dose of DEX 1 µg/kg for 10 min, and a maintenance dose of DEX 0.5 µg/kg/h of either IBW or TBW, may induce excessive sedation, airway obstruction, and/or coughing under spinal anesthesia.
Airway Obstruction* ; Anesthesia, Spinal* ; Body Weight ; Capillaries ; Consciousness Monitors ; Cough ; Dexmedetomidine* ; Humans ; Ideal Body Weight ; Incidence ; Oxygen ; Vital Signs

BACKGROUND/AIMS: The efficacy of bispectral index (BIS) monitoring during colonoscopic sedation is debated. We aimed to determine whether BIS monitoring was useful for propofol dose titration, and to evaluate differences in sedative administration between expert and inexperienced medical personnel during colonoscopy procedures that required moderate sedation. METHODS: Between February 2012 and August 2013, 280 consecutive patients scheduled to undergo a screening colonoscopy participated in this study and were randomly allocated to the expert or inexperienced endoscopist group. Each group was further divided into either a BIS or a modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S) subgroup. Trained nurses administered combined propofol sedation and monitored sedation using either the BIS or MOAA/S scale. RESULTS: The mean BIS value throughout the procedure was 74.3 +/- 6.7 for all 141 patients in the BIS group. The mean total propofol dose administered in the BIS group was higher than that in the MOAA/S group, independently of the endoscopists' experience level (36.9 +/- 29.6 and 11.3 +/- 20.7, respectively; p < 0.001). The total dose of propofol administered was not significantly different between the inexperienced endoscopist group and the expert endoscopist group, both with and without the use of BIS (p = 0.430 and p = 0.640, respectively). CONCLUSIONS: Compared with monitoring using the MOAA/S score alone, BIS monitoring was not effective for titrating the dose of propofol during colonoscopy, irrespective of colonoscopist experience.
Adult ; Aged ; Anesthetics, Intravenous/*administration & dosage/adverse effects ; *Clinical Competence ; *Colonoscopy ; Conscious Sedation/adverse effects/*nursing ; Consciousness/*drug effects ; *Consciousness Monitors ; Electroencephalography/*instrumentation/*nursing ; Female ; Humans ; Male ; Middle Aged ; *Nurse Anesthetists ; Predictive Value of Tests ; Propofol/*administration & dosage/adverse effects ; Prospective Studies ; Republic of Korea

BACKGROUND: This study was designed to determine the optimal anesthetic depth for the maintenance and recovery in interventional neuroradiology. METHODS: Eighty-eight patients undergoing interventional neuroradiology were randomly allocated to light anesthesia (n = 44) or deep anesthesia (n = 44) groups based on the value of the bispectral index (BIS). Anesthesia was induced with propofol, alfentanil, and rocuronium and maintained with 1-3% sevoflurane. The concentration of sevoflurane was titrated to maintain BIS at 40-49 (deep anesthesia group) or 50-59 (light anesthesia group). Phenylephrine was used to maintain the mean arterial pressure within 20% of preinduction values. Recovery times were recorded. RESULTS: The light anesthesia group had a more rapid recovery to spontaneous ventilation, eye opening, extubation, and orientation (4.1 +/- 2.3 vs. 5.3 +/- 1.8 min, 6.9 +/- 3.2 min vs. 9.1 +/- 3.2 min, 8.2 +/- 3.1 min vs. 10.7 +/- 3.3 min, 10.0 +/- 3.9 min vs. 12.9 +/- 5.5 min, all P < 0.01) compared to the deep anesthesia group. The use of phenylephrine was significantly increased in the deep anesthesia group (768 +/- 184 vs. 320 +/- 82 microg, P < 0.01). More patients moved during the procedure in the light anesthesia group (6/44 [14%] vs. 0/44 [0%], P = 0.026). CONCLUSIONS: BIS values between 50 and 59 for interventional neuroradiology were associated with a more rapid recovery and favorable hemodynamic response, but also with more patient movement. We suggest that maintaining BIS values between 40 and 49 is preferable for the prevention of patient movement during anesthesia for interventional neuroradiology.
Alfentanil ; Anesthesia* ; Anesthesia, General ; Arterial Pressure ; Consciousness Monitors ; Hemodynamics ; Humans ; Phenylephrine ; Propofol ; Radiology, Interventional ; Ventilation