Comparison of the tidal volume by the recruitment maneuver combined with positive end-expiratory pressure for mechanically ventilated children.

The recruitment maneuver (RM) combined with PEEP to prevent atelectasis have beneficial effects. However, the change in tidal volume (VT) due to RM combined with PEEP in pediatric patients during the induction of general anesthesia is unknown. Therefore, we assessed the effects of RM combined with PEEP on VT. Pediatric patients were divided into three groups: infants, preschool children, and school children. The RM was performed by maintaining pressure control continuous mandatory ventilation (PC-CMV) with a 15 cmH2O and PEEP increase of 5 cmH2O. VT, respiratory function and hemodynamics were monitored before and after RM combined with PEEP. VT (mL) /ideal body weight (kg) before vs. after RM combined with PEEP were 9 vs 12 mL/kg (p < 0.05) in the infants, 9 vs 11 mL/kg (p < 0.05) in the preschool children, 8 vs 10 mL/kg (p < 0.05) in the school children, respectively. HR and BP before and after RM combined with PEEP increased by 2-3% and decreased by 4-7% in all groups. RM combined with PEEP resulted in an increase in VT per ideal body weight (1.1-1.2%). Therefore, this RM combined with PEEP method might improve the lung function in pediatric patients.

Positional Change Used to Manage Postextubation Respiratory Failure in a Child With Cerebral Palsy.

Dental treatment for patients with cerebral palsy (CP) is often performed under general anesthesia due to involuntary movements that can render dental treatment difficult. Since CP is often accompanied by spasticity, care must be taken when positioning patients during general anesthesia. We report the management of a 14-year-old girl with CP and epilepsy undergoing general anesthesia for dental treatment who experienced respiratory failure due to acute thoracoabdominal muscle hypertonia after extubation. She had a history of cardiac arrest due to respiratory failure caused by acute muscle hypertonia and successful resuscitation. General anesthesia was induced after careful positioning of the patient to prevent spastic muscle stretching, and the dental treatment was completed without complications. However, upon awakening after extubation, the patient developed respiratory failure due to acute muscle hypertonia. The patient was resedated and repositioned from a supine to a sitting position, and her symptoms improved. There was no recurrence of muscle hypertonia, and she recovered fully without complications. In this case, respiratory failure associated with acute muscle hypertonia was successfully managed by position change after initial treatment with positive-pressure ventilation and propofol. It is important to be prepared for the possibility of respiratory failure associated with acute muscle hypertonia and its countermeasures when providing general anesthesia for patients with CP.

The difference in rotation angle of the distal endotracheal tube through nasal approach.

BACKGROUND: Nasal intubation using a fiberoptic scope is a useful technique. In clinical practice, we have experienced difficulty in advancing the endotracheal tube (ETT) over the fiberoptic scope because of resistance to the passage of the ETT against rotation in the nasal cavity, when it gets hung up on structures of the laryngeal inlet. Several maneuvers have been proposed to overcome this difficulty. The gap between the tip of the ETT and the fiberoptic scope can be reduced using a thicker fiberoptic scope and a thinner ETT. Moreover, simultaneous rotation of the fiberoptic scope and ETT could lead to successful intubation by reducing impingement on the ETT. However, the discrepancy between these rotation angles is unclear. This observational prospective study aimed to investigate the discrepancy in the rotation angle between the ETT and fiberoptic scope during nasal intubation. METHODS: The patients (aged 20-80 years) who underwent nasal intubation for oral and maxillofacial surgery participated in three sizes of preformed nasal ETT and were intubated using a fiberoptic scope. They were divided into three groups; the ETT internal diameter (ID) 6.5 mm (6.5 group), ID 7.0 mm (7.0 group), and ID 7.5 mm (7.5 group). The ETT was then inserted through the nasal cavity into the pharynx. After the fiberoptic scope was advanced through the ETT above the glottis, simultaneous rotation by both the proximal end of the fiberoptic scope and ETT was performed in 90° and 180° in both right (clockwise) and left (counterclockwise) directions, and the rotation angle at the distal end of the ETT was monitored using a video laryngoscope (Pentax-AWS). RESULTS: A total of 39 patients were included in the study. When both the proximal end of the fiberscope and ETT were simultaneously rotated by 90°, in the 6.5 group (n = 13), the distal end of the ETT rotated by 47.8 ± 1.5°. In the 7.0 °group (n = 13), the distal end of the ETT rotated by 45.5 ± 1.0°. In the 7.5 group (n = 13), the distal end of the ETT rotated by 39.9 ± 1.0°. When the proximal end of the fiberscope and ETT were rotated by 180°, in the 6.5 group, the distal end of the ETT rotated by 166.2 ± 2.5°. In the 7.0 group, the distal end of the ETT rotated by 145.7 ± 2.2°. In the 7.5 group, the distal end of the ETT rotated by 115.1 ± 2.0°. All rotation angles in the distal end of the ETT were significantly lower than those in both the proximal end of the fiberscope and ETT (p < 0.05). Rotating right by 180° was significantly different among the three groups (p < 0.05), although rotating right by 90° was not significantly different. Similar results were obtained for the left rotation. CONCLUSION: Simultaneous rotation by the proximal end of the ETT and fiberscope above the glottis for the nasal approach induced significant differences in the distal end of the ETT. The larger tube lagged by the resistance of the nasal passages during rotation. Therefore, the ETT does not rotate as much as the rotation angle. TRIAL REGISTRATION: This prospective observational study was conducted after receiving approval from the Ethics Review Board of Kyushu University Hospital (Approval No. 30-447).

Risk Factors for Postoperative Sore Throat After Nasotracheal Intubation.

OBJECTIVE: Postoperative sore throat is relatively frequent complication after orotracheal intubation. However, there are few reports about postoperative sore throat in nasotracheal intubation. In this retrospective study, we investigated the risk factors of postoperative sore throat in nasotracheal intubation. METHODS: Anesthesia records of patients 16 to 80 years of age who underwent nasotracheal intubation were included. Patients underwent oral and maxillofacial surgery from February 2015 until September 2018. Airway device (Macintosh laryngoscope, Pentax-AWS, or McGRATH video laryngoscope, or fiberoptic scope), sex, age, height, weight, American Society of Anesthesiologists classification, intubation attempts, duration of intubation, intubation time, tube size, and fentanyl and remifentanil dose were investigated. Fisher exact test, Wilcoxon rank sum test, Welch t test, and Steel-Dwass multiple test were used, and a multivariable analysis was performed using stepwise logistic regression to determine the risk factors of postoperative sore throat. RESULTS: A total of 169 cases were analyzed, and 126 patients (74.6%) had a postoperative sore throat. Based on the univariate analysis of the data, 12 factors were determined to be potentially related to the occurrence of a postoperative sore throat. However, after evaluation using stepwise logistic regression analysis, the 2 remaining variables that correlated with postoperative sore throat were airway device (P < .05) and intubation attempts (P = .04). In the model using logistic regression analysis, the fiberoptic scope had the strongest influence on the incidence of sore throat with reference to Pentax-AWS (odds ratio = 5.25; 95% CI = 1.54-17.92; P < .05). CONCLUSION: Use of a fiberoptic scope was identified as an independent risk factor for postoperative throat discomfort. Compared with direct laryngoscopy and other video laryngoscopes, the use of a fiberoptic scope had a significantly higher incidence of sore throat.

Comparison of different methods of more effective chest compressions during cardiopulmonary resuscitation (CPR) in the dental chair.

Introduction: When performing cardiopulmonary resuscitation (CPR) on a patient who has suffered a cardiopulmonary arrest during dental treatment, few dental chairs have sufficient stability to perform effective chest compressions. We previously proposed a method of stabilizing the backrest of a dental chair using a support stool. As a result, we confirmed that the vertical displacement of the backrest could be significantly reduced. In the present study, we verified the effectiveness of the stool stabilization method using several dental chairs (flat and curved) with significantly different backrest shapes. Methods: Vertical displacement of the backrests of dental chairs was recorded. Data were obtained at three different stool positions (without a stool, under the chest at the level that participants were performing manual chest compressions, and under the shoulders). Reduction displacement ratios were calculated to evaluate the effectiveness of the stool positions. Results: The method significantly reduced the vertical displacement of the backrest for all types. When the curvature of the backrest was large, the reduction in vertical displacement was 40% when the stool was placed under the chest at the level of manual chest compressions and 65% when placed underneath the shoulder. In the case of a flat dental chair, this reduction was 90% when using a stool in either position, compared to no stool. Conclusion: When we need to perform CPR on a patient in the dental chair, placing a stool under the shoulders allows effective manual chest compression by firmly supporting the backrest of a dental chair of any shape.

The influence of electrocardiogram (ECG) filters on the heights of R and T waves in children.

Anesthesiologists often compare intraoperative and preoperative electrocardiogram (ECG) waveforms in patients undergoing general anesthesia. In addition, many intraoperative ECG monitors have filters for removing electrocautery noise. In pediatric anesthesiology practice, we often note the appearance of elevated T waves-specifically, an increase in their height-with the use of such filters, even though no actual clinical change has occurred, which possibly leads to misdiagnosis. We investigated changes in R and T wave heights and in the T/R ratio according to the use of the strong (S) versus the diagnostic (D) filtering mode during pediatric anesthesiology. Primary outcomes were the dependence of the heights of the R and T waves on the filter mode and the correlation between rates of change in the R- and T-wave heights and heart rate (HR). In the S mode, the height of the R wave was lower (p = 0.013, η2 = 0.28) and the T/R ratio was higher than the corresponding values in the D mode (χ2 = 20.46, p < 0.001). The T/R ratios were also higher in the S mode than in the D mode, and when the D mode was changed to the S mode during tachycardia, there was a strong correlation between the rate of reduction in the R wave and HR (r = 0. 573, p = 0.041). Significant differences in the heights of the R wave and in the T/R ratio occur when using different intraoperative ECG filtering modes. Specifically, in S mode, a greater relative increase in T wave height may occur due to a significant decrease in R wave height. To avoid spurious diagnoses, anesthesiologists should be familiar with these potentially purely filter-driven changes whenever ECG is intraoperatively monitored.

Alternative Technique for Nasotracheal Intubation Using a Flexible Fiberoptic Scope.

In oral maxillofacial surgery, the endotracheal tube (ETT) is often inserted nasotracheally to provide surgeons a better view and easier access to the oral cavity. Use of a flexible fiberoptic scope is an effective technique for difficult intubation. While the airway anatomy can be observed as the scope is advanced, the ETT tip cannot be observed with the traditional method. It is occasionally difficult to advance the ETT beyond the glottis as impingement of the ETT tip may occur. We devised a new nasotracheal intubation technique using a fiberoptic scope. In this novel technique, the ETT and fiberoptic scope are inserted into the pharyngeal space separately through the right and left nasal cavities. This permits continuous observation of the glottis as the ETT is advanced into the trachea. The main advantage of this technique is that the ETT tip is visualized as it is advanced, which helps avoid impingement of the ETT. If resistance is noted, the ETT can easily be rotated or withdrawn without causing laryngeal damage, leading to safe and smooth intubation. This novel technique allows advancement of the ETT under continuous indirect vision, thus minimizing contact of the ETT with the laryngeal structures and aiding in unhindered passage into the glottis.

A Comparison of Two Stool Positions for Stabilizing a Dental Chair During CPR.

OBJECTIVE: Most dental chairs lack sufficient stability to perform effective manual chest compression (MCC) during cardiopulmonary resuscitation (CPR). A stabilizing stool can significantly reduce backrest vertical displacement in all chair types; however, a severely curved exterior backrest may negatively impact the stool's effectiveness. This study evaluated the efficacy of 2 stool positions for stabilizing a dental chair during MCC. METHODS: Chest compressions were performed on a manikin positioned in a dental chair while vertical displacement of the chair backrest during MCC was recorded using video and measured. Vertical displacement data were captured with no stool and with a stabilizing stool in 2 different positions. Reduction ratios were calculated to evaluate the effectiveness of the 2 stool positions. RESULTS: With no stool, the backrest median (interquartile range) vertical displacement during chest compressions was 16.5 (2.5) mm as compared with 12.0 (1.5) mm for the stabilizing stool positioned under the area of MCC and 8.5 (1.0) mm under the shoulders. The stool positioned under the shoulders produced a significantly increased calculated reduction ratio of 48% (14%) compared with 27% (20%) under the area of MCC (P < .001). CONCLUSIONS: Positioning a stabilizing stool under the shoulders was more effective at reducing vertical displacement of the dental chair backrest during chest compressions than positioning the stool under the area of MCC.

Sevoflurane concentration for cannulation in developmental disabilities.

OBJECTIVE: The goal of this study was to compare the end-tidal sevoflurane concentration and time for intravenous cannulation at induction of anesthesia using sevoflurane with or without nitrous oxide in healthy children and in those with developmental disabilities. METHODS: Normal and developmentally disabled children were anesthetized by inhalation of sevoflurane with nitrous oxide or with nitrous oxide-free oxygen, and intravenous cannulae were introduced. Nitrous oxide was stopped after loss of consciousness. The following parameters were recorded for each patient: age, gender, height, weight, BMI, duration of intravenous cannulation, end-tidal concentration of sevoflurane at the completion of intravenous cannulation, and use of nitrous oxide. For each parameter except gender, p-value were calculated by one-way analysis of variance (ANOVA). For gender, p-value were calculated using the Fisher method. Two-way ANOVA was performed to evaluate the effect of patient health status and nitrous oxide use on the end-tidal concentrations of sevoflurane and the time required for intravenous cannulation. RESULTS: The end-tidal sevoflurane concentrations at the completion of the intravenous cannulation had received a significant main effect of the factor "the use of nitrous oxide" (F(1,166) = 25.8, p < 0.001, η2 = 0.13) and a small effect of the factor "the patient health status" (F(1,166) = 0.259, p = 0.611, η2 = 0.001). However, the time required for intravenous cannulation was not significantly affected by either of the two factors, "the use of nitrous oxide" (F(1,166) = 0.454, p = 0.501, η2 = 0.003) and "the patient health status" (F(1,166) = 0.308, p = 0.579, η2 = 0.002). CONCLUSIONS: Between the healthy children and the children with developmental disabilities, no significant differences in the time required for the intravenous cannulation from the beginning of anesthetic induction. However, the end-tidal sevoflurane concentrations at the completion of the intravenous cannulation was significantly different. Sevoflurane in alveoli might be diluted by nitrous oxide.

Quantification and Visualization of Reliable Hemodynamics Evaluation Based on Non-Contact Arteriovenous Fistula Measurement.

The condition of arteriovenous fistula (AVF) blood flow is typically checked by using auscultation; however, auscultation should require a qualitative judgment dependent on the skills of doctors, and further attention to contact infection is required. For these reasons, this study developed a non-contact and non-invasive medical device to measure the pulse wave of AVFs by applying optical imaging technology. As a first step toward realization of the quantification judgment based on non-contact AVF measurement, we experimentally validated the developed system, whereby the hemodynamics of 168 subjects were visually and quantitatively evaluated based on clinical tests. Based on the evaluation results, the fundamental statistical characteristics of the non-contact measurement, including the average and median values, and distribution of measured signal-to-noise power ratio, were demonstrated. The clinical test results contributed to the future construction of quantified criteria for the AVF condition with the non-contact measurement.

A Case of Laryngeal Granulomas After Oral and Maxillofacial Surgery With Prolonged Intubation.

Laryngeal granuloma development can be a postoperative complication of laryngeal trauma or irritation resulting from general anesthesia and endotracheal intubation. These rare benign lesions are located primarily over the cartilaginous portions of the larynx, particularly the vocal processes of the arytenoids. Airway manipulation during the intubation process and prolonged intubation periods can be contributing factors to intubation-related laryngeal granulomas, which may manifest 1 to 4 months after intubation. The patient in this case was a female who returned with complaints of throat pain without hoarseness or sensations of a "lump in her throat" 3 months following surgery, during which she was intubated with a 7.0-mm nasotracheal tube for 30 hours, likely contributing to her bilateral laryngeal granulomas. The patient underwent successful conservative medical management consisting of a proton pump inhibitor and an inhaled corticosteroid.

Prediction of appropriate formula for nasotracheal tube size in developmental disability children.

OBJECTIVES: Developmental disability children have differences in growth. Therefore, tube size selection is important for nasotracheal intubation. In our previous study for healthy children undergoing dental surgery, height was the most suitable factor to predict nasotracheal tube size. The aim of this study was to find the most suitable formula for selection of nasotracheal tube size for them, retrospectively. MATERIAL AND METHODS: Developmental disability children aged 2 to 10 years were included in this study. They were intubated nasotracheally from April 2012 until May 2017. Their actually intubated tube sizes were checked. The predicted tube sizes were calculated according to the formulas by the backgrounds: the diameter of the trachea at the 6th cervical (C6), 7th cervical (C7), and 2nd thoracic vertebrae (T2) in X-ray. The actually intubated tube sizes were compared with predicted sizes. Data were analyzed using Spearman's regression analysis. RESULTS: The tube sizes with 5.0, 5.5, and 6.0 mm ID were intubated in 75 patients. The age-based formula was the most suitable; the correlation coefficients (r2) were 0.9027 (vs age), 0.5434 (vs height), 0.3779 (vs weight), 0.0785 (vs C6), 0.2279 (vs C7), and 0.3065 (Th2) (p < 0.01). However, 0.5-mm smaller size tubes were more frequently intubated actually. Their correspondence rate to the predicted size was 48% (5.0 mm), 52% (5.5 mm), and 39% (6.0 mm), respectively. CONCLUSION: The age-based formula could be the most suitable for predicting nasotracheal tube size in developmental disability children aged 2 to 10 years. One smaller size by the age formula was most suitable at first trial tube. CLINICAL RELEVANCE: The present data indicate that the selection of nasotracheal tube using one smaller size by the age formula (ID = 4 + age [years]/4) might be useful for developmental disability children.

Cleft-lip-plate patient with tracheobronchomalacia: A case report and review of the literature in Japan.

BACKGROUND: Tracheobronchomalacia (TBM) is a severe life-threatening perioperative complication. It is a rare condition caused by congenital and developmental anomalies of the trachea and/or the bronchus. It is often difficult to diagnose TBM before surgery as this congenital disease presents very few symptoms preoperatively and most often appears postoperatively. CASE PRESENTATION AND REVIEW: The study describes a case of cleft-lip-plate (CL/P) in a 7-month-old Japanese female with TBM and Tetralogy of Fallot syndrome. Before undergoing cleft-lip surgery, her TBM was not fully elucidated by preoperative examinations, and the operation was completed uneventfully. After the surgery, however, she started showing severe respiratory distress and developed hypoxia and bradycardia in the operating room. CPR was performed successfully, but a bronchoscopy revealed a severely collapsed airway, and the pathological condition was diagnosed as TBM occurred postoperatively. Eight months later, she died of sudden respiratory failure similar to that of the postoperative event caused by TBM. A literature review was conducted on the complications of CL/P from 1990 to 2017 in Japan. CONCLUSIONS: It was hypothesized that CL/P with congenital heart disease (CHD) and TBM with CHD may crossover in relatively high rates. Currently, there are very few solutions available to treat severe airway obstruction related to TBM. This highlights the need for preoperative diagnosis of TBM as an important step in overcoming severe airway complications.

Effective Method Using a Stool in Cardiopulmonary Resuscitation (CPR) on Dialysis Chair.

BACKGROUND: Heart failure is the leading cause of death in dialysis patients. Cardiac arrest due to hypotension may also occur during dialysis therapy. If cardiac arrest is elicited, manual chest compressions (MCCs) should be started as soon as possible. However, all types of dialysis chairs are not stable for MCC, because there is no steady support between the backboard of the dialysis chair and the floor. These conditions may alter the effectiveness of MCC. METHODS: We investigated whether a round chair is effective in supporting the dialysis chair for MCC. Four adult males performed MCC on a mannequin placed on three dialysis chairs. MCC was performed in sets of 2 (each set was 100 times per minute) per person, with and without a round chair. A total of 4,800 compressions were performed by four executors. RESULTS: When the chair was not used as a stabilizer, the mean values of the fluctuation range were 20.8 ± 8.1 mm, 18.7 ± 5.5 mm, and 12.8 ± 1.8 mm, respectively. When the chair was used, the mean values of the fluctuation range were 6.1 ± 1.1 mm, 7.5 ± 2.1 mm, and 1.0 ± 0 mm, decreasing by 70%, 59%, and 92%. CONCLUSION: MCC performed with the stool under the backrest as a stabilizer was effective in supporting the dialysis chair.

Mask Induction for an Intellectually Disabled Patient With Congenital Infiltrating Lipomatosis of the Face.

Airway management for patients with craniofacial disorders poses many challenges. Congenital infiltrating lipomatosis of the face (CILF) is an extremely rare disorder in which mature lipocytes invade adjacent tissues in the head and neck. The manifestations are typically unilateral, often with associated hypertrophy of both the hard and soft tissues of the face. This is a case report regarding the anesthetic management for a 5-year-old intellectually disabled female with CILF involving the right side of her face who underwent a successful intubated general anesthetic for dental treatment. Awake fiber-optic intubations are recommended and routinely used for patients with suspected or confirmed difficult airways. In this case, substantial distortion of the normal facial anatomy was observed clinically with noted hypertrophy of the right maxilla, mandible, and right side of the tongue. Further complicating matters was the patient's inability to fully cooperate because of her intellectual disability, precluding the option of an awake fiber-optic intubation. To secure the airway following mask induction of anesthesia, spontaneous ventilation was carefully maintained using sevoflurane, nitrous oxide, and oxygen combined with the application of a nasopharyngeal airway. Despite compression of the oral cavity and upper pharyngeal space by the hypertrophic tissues due to CILF, the space in and around the glottis was preserved. Intubation was completed easily with the use of a fiber-optic scope without any serious complications.

Influence of measurement principle on total hemoglobin value.

BACKGROUND: Total hemoglobin (tHb) measurement is indispensable for determining the patient's condition (hemorrhagic vs. ischemic) and need for blood transfusion. Conductivity- and absorbance-based measurement methods are used for blood gas analysis of tHb. For conductivity-based measurement, tHb is calculated after converting blood conductivity into a hematocrit value, whereas absorbance measurement is based on light absorbance after red blood cell hemolysis. Due to changes in plasma electrolytes and hemolysis, there is a possibility that conductivity- and absorbance-based measurement methods may cause a difference in tHb. METHODS: In this study, test samples with controlled electrolyte changes and hemolysis were created by adding sodium chloride, distilled water or hemolytic blood to blood samples collected from healthy volunteers, and tHb values were compared between both methods. RESULTS: Conductivity-based measurement revealed reduced tHb value (from 15.49 to 13.05 g/dl) following the addition of 10% sodium chloride, which was also reduced by the addition of hemolysate. Conversely, the addition of distilled water significantly increased tHb value than the expected value. In the absorbance method, there was no significant change in tHb value due to electrolyte change or hemolysis. CONCLUSIONS: We have to recognize unexpected conductivity changes occur at all times when tHb is measured via conductivity- and absorbance-based measurement methods. The absorbance method should be used when measuring tHb in patients with expected blood conductivity changes. However, when using this method, the added contribution of hemoglobin from hemolytic erythrocytes lacking oxygen carrying capacity must be considered. We recognize that discrepancy can occur between conductivity- and absorbance-based measurement methods when tHb is measured.

Endotracheal Tube Migration Associated With Extension During Tracheotomy.

Tracheotomy is occasionally performed to prevent postoperative airway obstruction especially for invasive surgical procedures involving head and neck cancer. When performed under general anesthesia, attention must be paid to avoid rupture of the tracheal tube cuff during the incision into the trachea. In this study, changes in the position of the endotracheal tube tip during extension of the head and neck for a tracheotomy were investigated. Twelve patients underwent placement of a tracheotomy during surgical procedures for oral cancer. After nasal intubation, the distance between the tube tip and the carina was measuring using a fiberoptic scope with the patient's head placed at an angle of 110°. Patients were repositioned for tracheotomy by placing a pillow under the shoulders and extending the head and neck at an angle of 140°. The distance measurements were subsequently repeated. The difference between the first and second measurements was calculated and analyzed statistically using a paired t test. On average the patients were 69.5 ± 9.0 years in age. The distance between the tube tip and the carina at an angle of 140° (3.6 ± 1.1 cm) was significantly longer than that at an angle of 110° (1.7 ± 1.0 cm) (p < 0.001). The migration in the positioning of the endotracheal tube tip was 1.9 ± 0.7 cm (range: 0.7-3.7 cm) upon extension. In 3 cases, the tube cuff was ruptured during incision of the trachea. The endotracheal tube tip may migrate in the cephalad direction approximately 2 cm as a result of the extension of the patient's head and neck during a tracheotomy. Therefore, consideration should be given to advancing the endotracheal tube tip towards the caudal side and to confirming the position of the tube and cuff during a tracheotomy.

Age-related effects of three inhalational anesthetics at one minimum alveolar concentration on electroencephalogram waveform.

BACKGROUND: The characteristics of electroencephalogram (EEG) profiles under general anesthesia may depend on age and type of anesthetic. AIM: This study investigated age-related differences in EEG waveforms between three inhalational anesthetics used at the same minimum alveolar concentration (MAC), which indicates the level of analgesia. METHODS: Patients with American Society of Anesthesiologists physical status I-II were divided into three groups according to age: pediatric (≦ 15 years); adult (16-64 years); and elderly (≧ 65 years). Each group was divided into three subgroups according to the inhalational anesthetic used: sevoflurane, isoflurane, and desflurane. Anesthesia was maintained at 1 MAC, followed by assessment of 95% spectral edge frequency (SEF95) values and amplitude of EEG waveform. RESULTS: The 3 age groups comprised a total of 180 patients. The mean (± SD) EEG waveform amplitude and SEF95 values for sevoflurane in the pediatric, adult, and elderly age groups, respectively, were: 32.9 ± 2.9 µV and 16.7 ± 2.4 Hz; 16.4 ± 3.6 µV and 12.2 ± 1.3 Hz; and 11.0 ± 2.1 µV and 13.6 ± 1.6 Hz. EEG waveform amplitude and SEF95 values were significantly higher in the pediatric group than in the other groups. SEF95 value was higher in the elderly group than in the adult group. Similar results were obtained for isoflurane and desflurane. CONCLUSION: The amplitude of the EEG waveform and SEF95 values varied with age, even at the same analgesic state in patients under general anesthesia. This age-dependent change in EEG waveform was observed for all three inhalational anesthetics, and should be considered in procedures requiring general anesthesia.