The Technology of Processed Electroencephalogram Monitoring Devices for Assessment of Depth of Anesthesia.

Commercial brain function monitors for depth of anesthesia have been available for more than 2 decades; there are currently more than 10 devices on the market. Advances in this field are evidenced by updated versions of existing monitors, development of new monitors, and increasing research unveiling the mechanisms of anesthesia on the brain. Electroencephalography signal processing forms an integral part of the technology supporting the brain function monitors for derivation of a depth-of-anesthesia index. This article aims to provide a better understanding of the technology and functionality behind these monitors. This review will highlight the general design principles of these devices and the crucial stages in electroencephalography signal processing and classification, with a focus on the key mathematical techniques used in algorithm development for final derivation of the index representing anesthetic state. We will briefly discuss the advantages and limitations of this technology in the clinical setting as a tool in our repertoire used for optimizing individualized patient care. Also included is a table describing 10 available commercial depth-of-anesthesia monitors.

Syringe Pump Performance Maintained with IV Filter Use During Low Flow Rate Delivery for Pediatric Patients.

BACKGROUND: Complex surgical and critically ill pediatric patients rely on syringe infusion pumps for precise delivery of IV medications. Low flow rates and in-line IV filter use may affect drug delivery. To determine the effects of an in-line filter to remove air and/or contaminants on syringe pump performance at low flow rates, we compared the measured rates with the programmed flow rates with and without in-line IV filters. METHODS: Standardized IV infusion assemblies with and without IV filters (filter and control groups) attached to a 10-mL syringe were primed and then loaded onto a syringe pump and connected to a 16-gauge, 16-cm single-lumen catheter. The catheter was suspended in a normal saline fluid column to simulate the back pressure from central venous circulation. The delivered infusate was measured by gravimetric methods at predetermined time intervals, and flow rate was calculated. Experimental trials for initial programmed rates of 1.0, 0.8, 0.6, and 0.4 mL/h were performed in control and filter groups. For each trial, the flow rate was changed to double the initial flow rate and was then returned to the initial flow rate to analyze pump performance for titration of rates often required during medication administration. These conditions (initial rate, doubling of initial rate, and return to initial rate) were analyzed separately for steady-state flow rate and time to steady state, whereas their average was used for percent deviation analysis. Differences between control and filter groups were assessed using Student t tests with adjustment for multiplicity (using n = 3 replications per group). RESULTS: Mean time from 0 to initial flow (startup delay) was <1 minute in both groups with no statistical difference between groups (P = 1.0). The average time to reach steady-state flow after infusion startup or rate changes was not statistically different between the groups (range, 0.8-5.5 minutes), for any flow rate or part of the trial (initial rate, doubling of initial rate, and return to initial rate), although the study was underpowered to detect small time differences. Overall, the mean steady-state flow rate for each trial was below the programmed flow rate with negative mean percent deviations for each trial. In the 1.0-mL/h initial rate trial, the steady-state flow rate attained was lower in the filter than the control group for the initial rate (P = 0.04) and doubling of initial rate (P = 0.04) with a trend during the return to initial rate (P = 0.06), although this same effect was not observed when doubling the initial rate trials of 0.8 or 0.6 mL/h or any other rate trials compared with the control group. CONCLUSIONS: With low flow rates used in complex surgical and pediatric critically ill patients, the addition of IV filters did not confer statistically significant changes in startup delay, flow variability, or time to reach steady-state flow of medications administered by syringe infusion pumps. The overall flow rate was lower than programmed flow rate with or without a filter.

Prior Podcast Experience Moderates Improvement in Electroencephalography Evaluation After Educational Podcast Module.

BACKGROUND: There is continued interest in using technology to enhance medical education and the variables that may affect its success. METHODS: Anesthesiology residents and fourth-year medical students participated in an electroencephalography (EEG) educational video podcast module. A 25-item evaluation tool was administered before any EEG education was provided (baseline), and the podcast was then viewed. Another 25-item evaluation tool was administered after podcast viewing (after podcast). Ten EEG interpretations were completed with a neurophysiologist with an additional 25-item evaluation tool administered after the interpretations (after 10 EEG interpretations). Participants were surveyed concerning technology and podcasting experience before the educational module and their responses to the podcast educational model. Multiple analyses were performed (1) to evaluate differences in improvement in EEG evaluation scores between the podcast module and the standard didactics (control group); and (2) to evaluate potential moderation by technology and the podcast experience on the change in mean EEG evaluation scores from after the podcast module to after 10 EEG interpretations. RESULTS: A total of 21 anesthesiology residents and 12 fourth-year medical students participated. Scores on the 25-item evaluation tool increased with each evaluation time (P ≤ 0.001). Moderation analyses revealed that individuals with more podcast experience (≥4 previous podcasts) had greater increases in scores after a podcast and 10 EEG interpretations compared with individuals with less experience (≤3 previous podcasts) (P = 0.027). Furthermore, compared with a control group with similar baseline characteristics that received only standard didactics without a podcast, those in the podcast group had greater increases in mean EEG evaluation scores between baseline and after 10 EEG interpretations. CONCLUSIONS: In reviewing the improvement in EEG evaluation after a podcast education module, those with more podcast experience achieved greater gains in EEG evaluation scores. For EEG education, those receiving the podcast education module showed greater increases in scores compared with those receiving didactic teaching without podcasting, as measured by change in a mean EEG evaluation scores.

Evaluating the long-term retention of a multidisciplinary electroencephalography instructional model.

BACKGROUND: Clinical decision making and problem solving require a core of basic factual knowledge that must be accessed sometimes months or years after it has been learned. We examined whether 10 compared with 20 total electroencephalogram (EEG) interpretations impacted scores for long-term retention with the residents in the 20 total EEG group assessed with additional examinations. METHODS: Study participants interpreted 10 (10 EEG group) or 20 (20 EEG group) EEGs during a month rotation. Using a 25-item evaluation tool, participants were assessed before any EEG interpretations and were reassessed with another 25-item assessment tool after 10 EEG interpretations with the neurophysiologist. The 20 EEG group also received unique 25-item assessments after 15 and 20 EEG interpretations. Long-term retention was assessed with a 40-item evaluation tool targeted for administration 12 months after the curriculum. The assessments were unique for the specific time points studied (baseline, after 10 EEG interpretations, after 15 EEG interpretations, after 20 EEG interpretations, and long term); all participants completed the same assessment tool for each specific time point assessed during the study. The assessment tools evaluated knowledge of EEG monitoring, anesthetic effects, and clinical EEG interpretation. RESULTS: Twenty anesthesiology residents completed the study with each group consisting of 10 residents. The mean scores represent the percentage of correct items, and for the 10 EEG group, the mean scores went from 42.8% ± 14.4% at baseline to 63.2% ± 8.0% (P < 0.001) after 10 EEG interpretations; however, there was no statistically significant difference noted from baseline to long-term retention 6.9% ± 9.0% (P = 0.78). Mean scores for the 20 EEG group improved from 34.4% ± 9.7% at baseline to 63.2% ± 6.2% (P < 0.001) after 10 EEGs and 62.3% ± 9.3% (P < 0.001) for long-term retention. Using a mixed model analysis, the only difference between the 10 and 20 EEG groups involved long-term retention with a total of 20 EEG interpretations compared with 10 (P = 0.006); there were no statistical differences between the groups at baseline (P = 0.065) or after 10 EEG interpretations (P = 1.00). DISCUSSION: Long-term retention was significantly improved after 20 compared with 10 EEG interpretations as evaluated by the assessment tools. Potential reasons for better long-term retention may relate to the total number of EEG interpretations with 2 additional spaced interval opportunities and evaluations reinforcing learning.

Chronic intercostal neuralgia after placement of right ventricle to pulmonary artery conduit with prosthetic valve.

Adults with congenital heart disease often have complex medical issues requiring individualised multidisciplinary care for optimising outcomes and quality of life. Chronic pain is an example. We report a rare case of intercostal neuralgia seemingly caused by irritation from a prosthetic valve in a right ventricle to pulmonary artery conduit in a patient with tetralogy of Fallot. Intercostal neuralgia is a painful disorder linked to nerve irritation or injury from trauma, infection or pressure. Although chronic postsurgical pain after cardiac surgery is prevalent, rarely the aetiology relates to valve irritation on a single intercostal nerve. After failing pharmacological therapy for 8 months, the neuralgia completely resolved after an ultrasound-guided neurolytic block with long-term effectiveness and improvement in patient satisfaction.

Particle Filtration Efficiency Testing of Sterilization Wrap Masks.

OBJECTIVES: Non-traditional materials are used for mask construction to address personal protective equipment shortages during the coronavirus disease 2019 (COVID-19) pandemic. Reusable masks made from surgical sterilization wrap represent such an innovative approach with social media frequently referring to them as "N95 alternatives." This material was tested for particle filtration efficiency and breathability to clarify what role they might have in infection prevention and control. METHODS: A heavyweight, double layer sterilization wrap was tested when new and after 2, 4, 6, and 10 autoclave sterilizing cycles and compared with an approved N95 respirator and a surgical mask via testing procedures using a sodium chloride aerosol for N95 efficiency testing similar to 42 CFR 84.181. Pressure testing to indicate breathability was also conducted. RESULTS: The particle filtration efficiency for the sterilization wrap ranged between 58% to 66%, with similar performance when new and after sterilizing cycles. The N95 respirator and surgical mask performed at 95% and 68% respectively. Pressure drops for the sterilization wrap, N95 and surgical mask were 10.4 mmH2O, 5.9 mmH2O, and 5.1 mmH2O, respectively, well below the National Institute for Occupational Safety and Health limits of 35 mmH2O during initial inhalation and 25 mmH2O during initial exhalation. CONCLUSIONS: The sterilization wrap's particle filtration efficiency is much lower than a N95 respirator, but falls within the range of a surgical mask, with acceptable breathability. Performance testing of non-traditional mask materials is crucial to determine potential protection efficacy and for correcting misinterpretation propagated through popular media.

Evaluating the requirements of electroencephalograph instruction for anesthesiology residents.

BACKGROUND: During a 1-mo neurosurgical intensive care unit rotation, anesthesiology residents interpret electroencephalograms (EEGs) performed throughout the institution, including intraoperative EEGs. The curriculum goal is to increase familiarity with EEG use and interpretation with 20 EEG interpretations with a clinical neurophysiologist during this rotation. We aimed to determine whether the EEG curriculum goals could be achieved with fewer EEG interpretations. METHODS: Each anesthesiology resident who participated interpreted 20 EEGs throughout the rotation. Using a 25-question evaluation tool, anesthesiology residents were assessed before interpreting any EEGs with a clinical neurophysiologist and reassessed after 10, 15, and 20 EEG interpretations. Each 25-item evaluation tool was developed to assess the impact of this EEG curriculum to gain experience with EEG monitoring and anesthetic effects using EEG tracings, and clinical EEG interpretation. RESULTS: Eight residents completed the study. Mean scores improved from 8.00 +/- 2.51 at baseline to 15.12 +/- 3.00 (P < 0.001), 15.88 +/- 3.18 (P < 0.001), and 18.12 +/- 3.23 (P < 0.001) after 10, 15, and 20 EEG interpretations. DISCUSSION: This innovative, collaborative approach using the expertise of the clinical neurophysiologist met the curriculum goals after 10 supervised EEG interpretations, as measured by the study assessment tool.

Evaluating an Interdisciplinary EEG Initiative on In-Training Examination EEG-Related Item Scores for Anesthesiology Residents.

PURPOSE: Clinical neurophysiology is an evolving area of medicine with clinical applications in intensive care unit and intraoperative settings, where EEG is used. An interdisciplinary module was implemented over 7 years in one institution to strengthen anesthesiology residents' EEG education. This study researched the module's outcome by evaluating participants' specific performance on EEG-related questions (keywords) through independent testing, i.e., the in-training examinations (ITEs). METHODS: Residency program ITE performance reports from 2002 to 2014 were searched for EEG keyword items. The ITE uses images for assessment. Analysis of variance was used to evaluate differences in the composite performance (mean percent correct on EEG-related keywords) of anesthesiology trainees from their clinical anesthesia year 1 (CA-1) to their clinical anesthesia year 3 (CA-3) who received the education module and compared with those who did not receive the training module, as well as compared with the national average for the corresponding training level. RESULTS: Residents who received the education module (mean percent correct = 83.3%, 95% CI: 74.0-92.7) performed significantly better than residents within the same program who did not receive the module (P = 0.04; mean difference = 22.0%, 95% CI: 1.0-43.0), as well as national residents on the same keywords (P = 0.01; mean difference = 23.4%, 95% CI: 3.9-42.9). Differences between residents who did not receive the module and national residents (matched for same keywords) were not statistically significant (P = 0.983, mean difference = 5.2%, 95% CI: -17.3 to 27.7). CONCLUSIONS: The multidisciplinary education module was effective for the EEG-specific topics as measured by the national ITE examination performance that resulted in sustained learning over time.

The effectiveness of a simple novel approach on electroencephalograph instruction for anesthesiology residents.

BACKGROUND: The electroencephalogram (EEG) measures cerebral activity and, because of its use as an intraoperative monitor, the Accreditation Council for Graduate Medical Education requires EEG monitoring experience during anesthesiology residency. To improve the anesthesiology residents' education at the University of Kentucky, a new learning module was created in collaboration with a neurologist expert in EEGs. METHODS: During the neurosurgical intensive care unit rotation, the anesthesiology residents interpreted intraoperative EEGs and EEGs performed throughout the institution. The number of EEGs interpreted during this experience ranged from 14 to 48. An evaluation tool of 25 items was developed to assess the impact of this experience, which included EEG tracings, clinical EEG interpretation and monitoring, and EEG anesthetic effects. RESULTS: Forty evaluations were performed on 33 residents. Seven residents had evaluations before and after the in depth EEG experience. Mean (se) scores of 25 items significantly improved from 10.7 +/- 3.9 to 18.9 +/- 3.0 (P < 0.001) after this educational opportunity. The residents with the new educational EEG exposure (n = 12, 19.2 +/- 3.4) scored better than did the residents with only the traditional approach without in depth EEG exposure (n = 14, 9.5 +/- 2.4). DISCUSSION: This educational effort using the department of neurology expertise provided a significant improvement in EEG assessment tool scores.

Revisiting the applicability of adult early post-operative nausea and vomiting risk factors for the paediatric patient: A prospective study using cotinine levels in children undergoing adenotonsillectomies.

BACKGROUND AND AIMS: Post-operative vomiting (POV) in children remains a significant clinical problem. This prospective study aims to investigate the applicability of well-established adult early post-operative nausea and vomiting (PONV) risk factors on paediatric POV after adenotonsillectomies under regulated anaesthetic conditions. METHODS: After Institutional Review Board approval, 213 children aged 3-10-year-old were enrolled. The participants had pre-operative questionnaires completed, followed protocolised anaesthetic plans and had saliva analysed for cotinine. The primary outcomes were POV as correlated with age, gender, family or personal history of PONV, motion sickness history, opioid use, surgical time, anaesthetic time and environmental tobacco smoke (ETS) exposure, as assessed by cotinine levels and questionnaire reports. Data on analgesics, antiemetics and POV incidence before post-anaesthesia care unit discharge were collected. Statistical analysis was done through multiple logistic regression. RESULTS: A total of 200 patients finalised the study. Early POV occurred in 32%. Family history of PONV (odds ratio [OR] = 5.3, P < 0.01) and motion sickness history (OR = 4.4, P = 0.02) were highly significant risk factors. Age reached borderline statistical significance (OR = 1.4, P = 0.05). None of the other factors reached statistical significance. CONCLUSION: Early POV occurs frequently in paediatric patients undergoing adenotonsillectomies. In this paediatric-aged group, the incidence of POV was affected by the family history of PONV, and history of motion sickness. Age, female gender, opioid use, surgical and anaesthetic times did not affect the incidence of POV. ETS exposure, as assessed by cotinine levels and questionnaire reports, had no protective effect on early paediatric POV.

The Post-Anesthetic Care of Pediatric Patients With Pulmonary Hypertension.

Few conditions make even the most experienced pediatric anesthesiologists take pause. Pulmonary hypertension is one such condition due to the associated high perioperative morbidity and mortality. Much is written about the intraoperative management of pediatric pulmonary hypertension. This article will instead focus on postoperative care and review the evidence in support of a risk stratification approach for the post-anesthetic disposition of these patients. The total risk for post-anesthetic adverse events includes the patient's baseline risk factors and the incremental risks imposed by the procedure and anesthetic. A proposal with recommendations to guide practitioners and a table summarizing relevant factors are provided. Last, the readers' attention is drawn to the heterogeneity of pulmonary hypertensive disease. Pulmonary arterial hypertension (precapillary) differs significantly from pulmonary venous hypertension (postcapillary); the anesthetic management for one may be relatively contraindicated in the other. Their dissimilarities justify the need to distinguish them for study and research endeavors.

Education research: evaluating the use of podcasting for residents during EEG instruction: a pilot study.

OBJECTIVE: Educational methods for residents are shifting toward greater learner independence aided by technological advances. A Web-based program using a podcast was created for resident EEG instruction, replacing conventional didactics. The EEG curriculum also consisted of EEG interpretations under the tutelage of a neurophysiologist. This pilot study aimed to objectively evaluate the effectiveness of the podcast as a new teaching tool. METHODS: A podcast for resident EEG instruction was implemented on the Web, replacing the traditional lecture. After Institutional Review Board approval, consent was obtained from the participating residents. Using 25-question evaluation tools, participants were assessed at baseline before any EEG instruction, and reassessed after podcasting and after 10 clinical EEG exposures. Each 25-item evaluation tool contained tracings used for clinical EEG interpretations. Scores after podcast training were also compared to scores after traditional didactic training from a previous study among anesthesiology trainees. RESULTS: Ten anesthesiology residents completed the study. The mean scores with standard deviations are 9.50 ± 2.92 at baseline, 13.40 ± 3.31 (p = 0.034) after the podcast, and 16.20 ± 1.87 (p = 0.019) after interpreting 10 EEGs. No differences were noted between the mean educational tool scores for those who underwent podcasting training compared to those who had undergone traditional didactic training. CONCLUSION: In this pilot study, podcast training was as effective as the prior conventional lecture in meeting the curricular goals of increasing EEG knowledge after 10 EEG interpretations as measured by assessment tools.

The effectiveness of an interdisciplinary approach to EEG instruction for residents(r).

Expanding EEG use calls for education during postgraduate training. We performed a study to see whether an innovative, interdisciplinary approach to EEG instruction for residents achieved curriculum goals of increasing knowledge of EEG use and interpretation. A 45-minute EEG educational module was developed by a clinical neurophysiologist and a neurocritical care anesthesiologist. After institutional review board approval and consent, neurologic surgery residents were evaluated using a 25-question assessment tool before and after the module to assess its impact. This tool included EEG tracing interpretations. Nine of 10 residents completed the study. Assessment tool scores increased from a mean of 12.00 +/- 1.87 before the educational module to 19.67 +/- 2.06 (P < 0.001) after the educational module. This innovative, collaborative approach for EEG instruction of residents using the expertise of a clinical neurophysiologist met the curriculum goals after a 45-minute educational module as measured by the study assessment tool.