Cecilia Canales

Accuracy and Precision of Continuous Noninvasive Arterial Pressure Monitoring Compared with Invasive Arterial Pressure: A Systematic Review and Meta-analysis

Background: Continuous noninvasive arterial pressure monitoring devices are available for bedside use, but the accuracy and precision of these devices have not been evaluated in a systematic review and meta-analysis. Methods: The authors performed a systematic review and meta-analysis of studies comparing continuous noninvasive arterial pressure monitoring with invasive arterial pressure monitoring. Random-effects pooled bias and SD of bias for systolic arterial pressure, diastolic arterial pressure, and mean arterial pressure were calculated. Continuous noninvasive arterial pressure monitoring was considered acceptable if pooled estimates of bias and SD were not greater than 5 and 8 mmHg, respectively, as recommended by the Association for the Advancement of Medical Instrumentation. Results: Twenty-eight studies (919 patients) were included. The overall random-effect pooled bias and SD were −1.6 ± 12.2 mmHg (95% limits of agreement −25.5 to 22.2 mmHg) for systolic arterial pressure, 5.3 ± 8.3 mmHg (−11.0 to 21.6 mmHg) for diastolic arterial pressure, and 3.2 ± 8.4 mmHg (−13.4 to 19.7 mmHg) for mean arterial pressure. In 14 studies focusing on currently commercially available devices, bias and SD were −1.8 ± 12.4 mmHg (−26.2 to 22.5 mmHg) for systolic arterial pressure, 6.0 ± 8.6 mmHg (−10.9 to 22.9 mmHg) for diastolic arterial pressure, and 3.9 ± 8.7 mmHg (−13.1 to 21.0 mmHg) for mean arterial pressure. Conclusions: The results from this meta-analysis found that inaccuracy and imprecision of continuous noninvasive arterial pressure monitoring devices are larger than what was defined as acceptable. This may have implications for clinical situations where continuous noninvasive arterial pressure is being used for patient care decisions.

Impact Assessment of Perioperative Point-of-Care Ultrasound Training on Anesthesiology Residents

Background:The perioperative surgical home model highlights the need for trainees to include modalities that are focused on the entire perioperative experience. The focus of this study was to design, introduce, and evaluate the integration of a whole-body point-of-care (POC) ultrasound curriculum (Focused periOperative Risk Evaluation Sonography Involving Gastroabdominal Hemodynamic and Transthoracic ultrasound) into residency training. Methods:For 2 yr, anesthesiology residents (n = 42) received lectures using a model/simulation design and half were also randomly assigned to receive pathology assessment training. Posttraining performance was assessed through Kirkpatrick levels 1 to 4 outcomes based on the resident satisfaction surveys, multiple-choice tests, pathologic image evaluation, human model testing, and assessment of clinical impact via review of clinical examination data. Results:Evaluation of the curriculum demonstrated high satisfaction scores (n = 30), improved content test scores (n = 37) for all tested categories (48 ± 16 to 69 ± 17%, P < 0.002), and improvement on human model examinations. Residents randomized to receive pathology training (n = 18) also showed higher scores compared with those who did not (n = 19) (9.1 ± 2.5 vs. 17.4 ± 3.1, P < 0.05). Clinical examinations performed in the organization after the study (n = 224) showed that POC ultrasound affected clinical management at a rate of 76% and detected new pathology at a rate of 31%. Conclusions:Results suggest that a whole-body POC ultrasound curriculum can be effectively taught to anesthesiology residents and that this training may provide clinical benefit. These results should be evaluated within the context of the perioperative surgical home.

High Fidelity Simulation Based Team Training in Urology: A Preliminary Interdisciplinary Study of Technical and Nontechnical Skills in Laparoscopic Complications Management

PURPOSE Simulation based team training provides an opportunity to develop interdisciplinary communication skills and address potential medical errors in a high fidelity, low stakes environment. We evaluated the implementation of a novel simulation based team training scenario and assessed the technical and nontechnical performance of urology and anesthesiology residents. MATERIALS AND METHODS Urology residents were randomly paired with anesthesiology residents to participate in a simulation based team training scenario involving the management of 2 scripted critical events during laparoscopic radical nephrectomy, including the vasovagal response to pneumoperitoneum and renal vein injury during hilar dissection. A novel kidney surgical model and a high fidelity mannequin simulator were used for the simulation. A debriefing session followed each simulation based team training scenario. Assessments of technical and nontechnical performance were made using task specific checklists and global rating scales. RESULTS A total of 16 residents participated, of whom 94% rated the simulation based team training scenario as useful for communication skill training. Also, 88% of urology residents believed that the kidney surgical model was useful for technical skill training. Urology resident training level correlated with technical performance (p=0.004) and blood loss during renal vein injury management (p=0.022) but not with nontechnical performance. Anesthesia resident training level correlated with nontechnical performance (p=0.036). Urology residents consistently rated themselves higher on nontechnical performance than did faculty (p=0.033). Anesthesia residents did not differ in the self-assessment of nontechnical performance compared to faculty assessments. CONCLUSIONS Residents rated the simulation based team training scenario as useful for interdisciplinary communication skill training. Urology resident training level correlated with technical performance but not with nontechnical performance. Urology residents consistently overestimated their nontechnical performance.

Closed-loop fluid administration compared to anesthesiologist management for hemodynamic optimization and resuscitation during surgery: an in vivo study.

BACKGROUND: Closed-loop systems have been designed to assist practitioners in maintaining stability of various physiologic variables in the clinical setting. In this context, we recently performed in silico testing of a novel closed-loop fluid management system that is designed for cardiac output and pulse pressure variation monitoring and optimization. The goal of the present study was to assess the effectiveness of this newly developed system in optimizing hemodynamic variables in an in vivo surgical setting. METHODS: Sixteen Yorkshire pigs underwent a 2-phase hemorrhage protocol and were resuscitated by either the Learning Intravenous Resuscitator closed-loop system or an anesthesiologist. Median hemodynamic values and variation of hemodynamics were compared between groups. RESULTS: Cardiac index (in liters per minute per square meter) and stroke volume index (in milliliters per square meter) were higher in the closed-loop group compared with the anesthesiologist group over the protocol (3.7 [3.4–4.1] vs 3.5 [3.2–3.9]; 95% Wald confidence interval, −0.5 to −0.23; P < 0.0005 and 40 [34–45] vs 36 [31–38]; 95% Wald confidence interval, −5.9 to −3.1; P < 0.0005, respectively). There was no significant difference in total fluid administration between the closed-loop and anesthesiologist groups (3685 [3230–4418] vs 3253 [2735–3926] mL; 95% confidence interval, −1651 to 431; P = 0.28). Closed-loop group animals also had lower coefficients of variance of cardiac index and stroke volume index during the protocol (11% [10%–16%] vs 22% [18%–23%]; confidence interval, 0.8%–12.3%; P = 0.02 and 11% [8%–16%] vs 17% [13%–21%]; confidence interval, 0.2%–11.4%; P = 0.04, respectively). CONCLUSION: This in vivo study building on previous simulation work demonstrates that the closed-loop fluid management system used in this experiment can perform fluid resuscitation during mild and severe hemorrhages and is able to maintain high cardiac output and stroke volume while reducing hemodynamic variability.

Intraoperative Stroke Volume Optimization Using Stroke Volume, Arterial Pressure, and Heart Rate: Closed-Loop (Learning Intravenous Resuscitator) Versus Anesthesiologists

OBJECTIVE The authors compared the performance of a group of anesthesia providers to closed-loop (Learning Intravenous Resuscitator [LIR]) management in a simulated hemorrhage scenario using cardiac output monitoring. DESIGN A prospective cohort study. SETTING In silico simulation. PARTICIPANTS University hospital anesthesiologists and the LIR closed-loop fluid administration system. INTERVENTIONS Using a patient simulator, a 90-minute simulated hemorrhage protocol was run, which included a 1,200-mL blood loss over 30 minutes. Twenty practicing anesthesiology providers were asked to manage this scenario by providing fluids and vasopressor medication at their discretion. The simulation program was also run 20 times with the LIR closed-loop algorithm managing fluids and an additional 20 times with no intervention. MEASUREMENTS AND MAIN RESULTS Simulated patient weight, height, heart rate, mean arterial pressure, and cardiac output (CO) were similar at baseline. The mean stroke volume, the mean arterial pressure, CO, and the final CO were higher in the closed-loop group than in the practitioners group, and the coefficient of variance was lower. The closed-loop group received slightly more fluid (2.1 v 1.9 L, p < 0.05) than the anesthesiologist group. CONCLUSIONS Despite the roughly similar volumes of fluid given, the closed-loop maintained more stable hemodynamics than the practitioners primarily because the fluid was given earlier in the protocol and CO optimized before the hemorrhage began, whereas practitioners tended to resuscitate well but only after significant hemodynamic change indicated the need. Overall, these data support the potential usefulness of this closed-loop algorithm in clinical settings in which dynamic predictors are not available or applicable.

Goal-Directed fluid therapy with closed-loop assistance during moderate risk surgery using noninvasive cardiac output monitoring: A pilot study

BACKGROUND Goal directed fluid therapy (GDFT) has been shown to improve outcomes in moderate to high-risk surgery. However, most of the present GDFT protocols based on cardiac output optimization use invasive devices and the protocols may require significant practitioner attention and intervention to apply them accurately. The aim of this prospective pilot study was to evaluate the clinical feasibility of GDFT using a closed-loop fluid administration system with a non-invasive cardiac output monitoring device (Nexfin™, BMEYE, Amsterdam, Netherlands). METHODS Patients scheduled for elective moderate risk surgery under general anaesthesia were enrolled. The primary anaesthesia team managing the case selected GDFT targets using the controller interface and all patients received a baseline 3 ml kg(-1) h(-1) crystalloid infusion. Colloid solutions were delivered by the closed-loop system for intravascular volume expansion using data from the Nexfin™ monitor. Compliance with GDFT management was defined as acceptable when a patient spent more than 85% of the surgery time in a preload independent state (defined as pulse pressure variation <13%) or when average cardiac index during surgery was >2.5 litre min(-1) m(-2). RESULTS A total of 13 patients were included in the study group. All patients met the established criteria for delivery of GDFT for greater than 85% of case time. The median length of stay in the hospital was 5 [3-6] days. CONCLUSION In this pilot study, GDFT management using the closed-loop fluid administration system with a non-invasive CO monitoring device was feasible and maintained a high rate of protocol compliance. CLINICAL TRIAL REGISTRATION NCT02020863.

Comparison of the didactic lecture with the simulation/model approach for the teaching of a novel perioperative ultrasound curriculum to anesthesiology residents ☆

STUDY OBJECTIVE To expose residents to two methods of education for point-of-care ultrasound, a traditional didactic lecture and a model/simulation-based lecture, which focus on concepts of cardiopulmonary function, volume status, and evaluation of severe thoracic/abdominal injuries; and to assess which method is more effective. DESIGN Single-center, prospective, blinded trial. SETTING University hospital. SUBJECTS Anesthesiology residents who were assigned to an educational day during the two-month research study period. MEASUREMENTS Residents were allocated to two groups to receive either a 90-minute, one-on-one didactic lecture or a 90-minute lecture in a simulation center, during which they practiced on a human model and simulation mannequin (normal pathology). Data points included a pre-lecture multiple-choice test, post-lecture multiple-choice test, and post-lecture, human model-based examination. Post-lecture tests were performed within three weeks of the lecture. An experienced sonographer who was blinded to the education modality graded the model-based skill assessment examinations. Participants completed a follow-up survey to assess the perceptions of the quality of their instruction between the two groups. MAIN RESULTS 20 residents completed the study. No differences were noted between the two groups in pre-lecture test scores (P = 0.97), but significantly higher scores for the model/simulation group occurred on both the post-lecture multiple choice (P = 0.038) and post-lecture model (P = 0.041) examinations. Follow-up resident surveys showed significantly higher scores in the model/simulation group regarding overall interest in perioperative ultrasound (P = 0.047) as well understanding of the physiologic concepts (P = 0.021). CONCLUSIONS A model/simulation-based based lecture series may be more effective in teaching the skills needed to perform a point-of-care ultrasound examination to anesthesiology residents.

High-Fidelity Simulation Enhances ACLS Training

Background: Medical student training and experience in cardiac arrest situations is limited. Traditional Advanced Cardiac Life Support (ACLS) teaching methods are largely unrealistic with rare personal experience as team leader. Yet Postgraduate Year 1 residents may perform this role shortly after graduation. Purposes: We expanded our ACLS teaching to a “Resuscitation Boot Camp” where we taught 2010 ACLS to 19 pregraduation students in didactic (12 hours) and experiential (8 hours) format. Methods: Immediately before the course, we recorded students performing an acute coronary syndrome/ventricular fibrillation (VF) scenario. As a final test, we recorded the same scenario for each student. Primary outcomes were time to cardiopulmonary resuscitation (CPR) and defibrillation (DF). Secondary measures were total scenario score, dangerous actions, proportion of students voicing “ventricular fibrillation,” 12-lead ST-elevation myocardial infarction (STEMI) interpretation, and care necessary for return of spontaneous circulation (ROSC). Two expert ACLS instructors scored both performances on a 121-point scale, with each student serving as their own control. We used t tests and McNemar tests for paired data with statistical significance at p <.05. Results: Before instruction, average time from arrest to CPR was 112 seconds and to first DF 3.01 minutes. Students scored 45 ± 9/121 points and 9/19 (49%) performed dangerous actions. After instruction, time to CPR was 12 seconds (p =.004) and to first DF 1.53 minutes (p =.03). Time to DF was delayed as students showed mastery of bag-valve-mask ventilation before DF. After instruction, students scored 97 ± 4/121 points (p <.0001) with no dangerous actions. Before training, only 4 of 19 (21%) students performed both CPR and DF within 2 minutes, and 3 of these had ROSC. After training, 14 of 19 (74%) achieved CPR + DF ≤ 2 minutes (p =.002), and all had ROSC. Before training, 5 of 19 (26%) students said “VF” and 4 of 19 obtained an ECG, but none identified STEMI. After training, corresponding performance was 13 of 19 “VF” (68%, p =.021) and 100% ECG and STEMI identification (p <.05). Conclusions: This course significantly improved knowledge and psychomotor skills. Critical actions required for resuscitation were much more common after training. ACLS training including high-fidelity simulation decreases time to CPR and DF and improves performance during resuscitation.

Positive end expiratory pressure during one-lung ventilation: selecting ideal patients and ventilator settings with the aim of improving arterial oxygenation.

The efficacy of positive end-expiratory pressure (PEEP) in treating intraoperative hypoxemia during one-lung ventilation (OLV) remains in question given conflicting results of prior studies. This study aims to (1) evaluate the efficacy of PEEP during OLV, (2) assess the utility of preoperative predictors of response to PEEP, and (3) explore optimal intraoperative settings that would maximize the effects of PEEP on oxygenation. Forty-one thoracic surgery patients from a single tertiary care university center were prospectively enrolled in this observational study. After induction of general anesthesia, a double-lumen endotracheal tube was fiberoptically positioned and OLV initiated. Intraoperatively, PEEP = 5 and 10 cm H(2)O were sequentially applied to the ventilated lung during OLV. Arterial oxygenation, cardiovascular performance parameters, and proposed perioperative variables that could predict or enhance response to PEEP were analysed. T-test and χ(2) tests were utilized for continuous and categorical variables, respectively. Multivariate analyses were carried out using a classification tree model of binary recursive partitioning. PEEP improved arterial oxygenation by ≥20% in 29% of patients (n = 12) and failed to do so in 71% (n = 29); however, no cardiovascular impact was noted. Among the proposed clinical predictors, only intraoperative tidal volume per kilogram differed significantly between responders to PEEP and non-responders (mean 6.6 vs. 5.7 ml/kg, P = 0.013); no preoperative variable predicted response to PEEP. A multivariate analysis did not yield a clinically significant model for predicting PEEP responsiveness. PEEP improved oxygenation in a subset of patients; larger, although still protective tidal volumes favored a positive response to PEEP. No preoperative variables, however, could be identified as reliable predictors for PEEP responders.

Correlation of Simulation Examination to Written Test Scores for Advanced Cardiac Life Support Testing: Prospective Cohort Study

Introduction Traditional Advanced Cardiac Life Support (ACLS) courses are evaluated using written multiple-choice tests. High-fidelity simulation is a widely used adjunct to didactic content, and has been used in many specialties as a training resource as well as an evaluative tool. There are no data to our knowledge that compare simulation examination scores with written test scores for ACLS courses. Objective To compare and correlate a novel high-fidelity simulation-based evaluation with traditional written testing for senior medical students in an ACLS course. Methods We performed a prospective cohort study to determine the correlation between simulation-based evaluation and traditional written testing in a medical school simulation center. Students were tested on a standard acute coronary syndrome/ventricular fibrillation cardiac arrest scenario. Our primary outcome measure was correlation of exam results for 19 volunteer fourth-year medical students after a 32-hour ACLS-based Resuscitation Boot Camp course. Our secondary outcome was comparison of simulation-based vs. written outcome scores. Results The composite average score on the written evaluation was substantially higher (93.6%) than the simulation performance score (81.3%, absolute difference 12.3%, 95% CI [10.6–14.0%], p<0.00005). We found a statistically significant moderate correlation between simulation scenario test performance and traditional written testing (Pearson r=0.48, p=0.04), validating the new evaluation method. Conclusion Simulation-based ACLS evaluation methods correlate with traditional written testing and demonstrate resuscitation knowledge and skills. Simulation may be a more discriminating and challenging testing method, as students scored higher on written evaluation methods compared to simulation.