Adam Wendling

A comparison of 4 airway devices on cervical spine alignment in cadaver models of global ligamentous instability at c1-2.

BACKGROUND:The effects of advanced airway management on cervical spine alignment in patients with upper cervical spine instability are uncertain. METHODS:To examine the potential for mechanical disruption during endotracheal intubation in cadavers with unstable cervical spines, we performed a prospective observational cohort study with 3 cadaver subjects. We created an unstable, type II odontoid fracture with global ligamentous instability at C1-2 in lightly embalmed cadavers, followed by repetitive intubations with 4 different airway devices (Airtraq laryngoscope, Lightwand, intubating laryngeal mask airway [LMA], and Macintosh laryngoscope) while manual in-line stabilization was applied. Motion analysis data were collected using an electromagnetic device to assess the degree of angular movement in 3 axes (flexion-extension, axial rotation, and lateral bending) during the intubation trials with each device. Intubation was performed by either an emergency medical technician or attending anesthesiologist. RESULTS:Overall, 153 intubations were recorded with the 4 devices. The Lightwand technique resulted in significantly less flexion-extension and axial rotation at C1-2 than with the intubating LMA (mean difference in flexion-extension 3.2° [95% confidence interval {CI}, 0.9°–5.5°], P = 0.003; mean difference in axial rotation 1.6° [95% CI, 0.3°–2.8°], P = 0.01) and Macintosh laryngoscope (mean difference in flexion-extension 3.1° [95% CI, 0.8°–5.4°], P = 0.005; mean difference in axial rotation 1.4° [95% CI 0.1°–2.6°], P = 0.03). CONCLUSIONS:In cadavers with instability at C1-2, the Lightwand technique produced less motion than the Macintosh and intubating LMA.

Comparison of 4 airway devices on cervical spine alignment in a cadaver model with global ligamentous instability at C5-C6.

Study Design. Human cadaveric study using various intubation devices in a cervical spine instability model. Objective. We sought to evaluate various intubation techniques and determine which device results in the least cervical motion in the setting of a global ligamentous instability model. Summary of Background Data. Many patients presenting with a cervical spine injury have other injuries that may require rapid airway management with endotracheal intubation. Secondary neurologic injuries may occur in these patients because of further displacement at the level of injury, vascular insult, or systemic decrease in oxygen delivery. The most appropriate technique for achieving endotracheal intubation in the patient with a cervical spine injury remains controversial. Methods. A global ligamentous instability at the C5–C6 vertebral level was created in lightly embalmed cadavers. An electromagnetic motion analysis device (Liberty; Polhemus, Colchester, VT) was used to assess the amount of angular and linear translation in 3 planes during intubation trials with each of 4 devices (Airtraq laryngoscope, lighted stylet, intubating LMA, and Macintosh laryngoscope). The angular motions measured were flexion-extension, axial rotation, and lateral bending. Linear translation was measured in the medial-lateral (ML), axial, and anteroposterior planes. Intubation was performed by either an emergency medical technician or by a board-certified attending anesthesiologist. Both time to intubate as well as failure to intubate (after 3 attempts) were recorded. Results. There was no significant difference shown with regards to time to successfully intubate using the various devices. It was shown that the highest failure-to-intubate rate occurred with use of the intubating LMA (ILMA) (23%) versus 0% for the others. In flexion/extension, we were able to demonstrate that the Lightwand (P = 0.005) and Airtraq (P = 0.019) resulted in significantly less angular motion than the Macintosh blade. In anterior/posterior translation, the Lightwand (P = 0.005), Airtraq (P = 0.024), and ILMA (P = 0.021) all caused significantly less linear motion than the Macintosh blade. In axial rotation, the Lightwand (P = 0.017) and Airtraq (P = 0.022) resulted in significantly less angular motion than the Macintosh blade. In axial translation (P = 0.037) and lateral bending (P = 0.003), the Lightwand caused significantly less motion than the Macintosh blade. Conclusion. In a cadaver model of C5–C6 instability, the greatest amount of motion was caused by the most commonly used intubation device, the Macintosh blade. Intubation with the Lightwand resulted in significantly less motion in all tested parameters (other than ML translation) as compared with the Macintosh blade. It should also be noted that the Airtraq caused less motion than the Macintoshblade in 3 of the 6 tested planes. There were no significant differences in failure rate or the amount of time it took to successfully intubate in comparing these techniques. We therefore recommend the use of the Lightwand, followed by the Airtraq, in the setting of a presumed unstable cervical spine injury over the Macintosh laryngoscope.

Exploring agent physicality and social presence for medical team training

Mixed reality and 3D user interface technologies have increased the immersion, presence, and physicality of user interactions. These technologies can also increase the physicality of embodied conversational agents (ECAs) by making the ECAs occupy and interact with the physical space. We propose that increasing the physicality of an ECA can increase the ECAs social presence, that is, the feeling that the ECA is a real person. In this paper, we examine existing research and formalize the idea of ECA physicality. We also explored the relationship between physicality and social presence by conducting two user studies (n 18 and n 29). Both user studies took place in a medical team training context and involved virtual human ECAs as fellow team members. The first studys results suggested that increasing physicality increased social presence and elicited more realistic behavior. The second studys results suggested that individual dimensions of physicality affect social presence to different extents.

Anesthetic management for cesarean section in a patient with rupture of a cerebellar arteriovenous malformation

Intracranial hemorrhage in the pregnant patient is a rare cause of peripartum morbidity, and it presents a diagnostic and management dilemma. The case of a term parturient who presented with headache is presented. Clinical suspicion led to the diagnosis of ruptured cerebellar arteriovenous malformation. Optimal timing of interventions, both neurosurgical and obstetric, are discussed. We chose to pursue Cesarean section prior to definitive neurosurgical intervention in this term parturient. Delivery of the fetus before surgery eliminates concern for adverse pregnancy outcome when interventions for cerebral protection are used, such as hyperventilation, administration of mannitol, barbiturate coma, and induced hypertension or hypotension. Subsequent management options, including general, spinal, epidural, and combined-spinal epidural (CSE) anesthesia for Cesarean delivery, are discussed. We selected CSE anesthesia so as to provide a hemodynamically stable delivery followed by planned endovascular embolization.

Virtual Humans Versus Standardized Patients: Which Lead Residents to More Correct Diagnoses?

Purpose Medical educators frequently use standardized patient (SP) encounters to bridge the gap between didactic education and practical application. Typically, SPs are healthy adults with no consistent physical findings; however, highly immersive virtual humans (VHs) may enable the consistent presentation of abnormal physical findings to multiple learners across multiple repetitions. Thus, the authors conducted this study to compare how frequently junior anesthesiology residents suspected obstructive sleep apnea (OSA) in preoperative assessments of SPs versus a VH. Method The authors presented a patient whose case included the historical features of OSA (snoring, daytime fatigue, observed apnea, hypertension, and obesity). Three SPs (in 2008) and one VH (in 2009) were necessary to run the residents through the assessment. The VH appeared morbidly obese and had a neck circumference of 40 inches. An airway exam of the VH displayed an image of redundant soft tissue, prominent tongue, and tonsillar hypertrophy. The VH responded to natural speech by recognizing “triggers” in a humans voice. The 849 triggers and 259 VH responses were designed with a technique that collects information from user interactions. Results Five of 21 residents (23.8%) suspected OSA after interviewing the SPs, whereas 11 of 13 residents (84.6%) suspected OSA after interviewing the VH (odds ratio of 17.6; 95% CI of 2.9–107). Conclusions Residents suspected OSA much more frequently after interviewing the VH than after interviewing the SPs. The VH provides a unique opportunity to display numerous abnormal physical findings as part of SP encounters.

Virtual Role-Models: Using Virtual Humans to Train Best Communication Practices for Healthcare Teams

Due to logistical scheduling challenges, social training of conflict resolution skills with healthcare professionals is a difficult task. To overcome these challenges, we used virtual humans to fill in as surgical teammates and train conflict resolution skills in a surgical scenario. Surgical technologists were recruited at a United States teaching hospital to interact with a virtual nurse, virtual surgeon, and virtual anesthesiologist in a team training exercise. Leveraging social learning theory, the virtual nurse on the team modeled one of two conflict resolution strategies, either best practices or bad practices, during an important decision moment in the exercise. In a second important decision moment, we assessed if surgical technologists demonstrated the conflict resolution model they observed. We found human participants were successfully able to demonstrate the ideal conflict resolution strategy after observing the virtual nurse model best practices. While we found participants were positively influenced by the best practices model, we also found that conversely, the bad practices model negatively influenced participants’ conflict resolution behavior. If humans can be positively influenced by virtual humans, this form of social training could transform medical team training, empowering more healthcare professionals to speak up, and potentially decreasing the chances of patient morbidity or death in the OR.

Increasing agent physicality to raise social presence and elicit realistic behavior

The concepts of immersion and presence focus on the environment in a virtual environment. We instead focus on embodied conversational agents (ECAs). ECAs occupy the virtual environment as interactive partners. We propose that the ECA analogues of immersion and presence are physicality and social presence. We performed a study to determine the effect of an ECAs physicality on social presence and eliciting realistic behavior from the user. The results showed that increasing physicality can elicit realistic behavior and increase social presence but there was also an interaction effect with plausibility.

Using a Critical Incident Scenario With Virtual Humans to Assess Educational Needs of Nurses in a Postanesthesia Care Unit

Introduction: During critical incidents, teamwork failures can compromise patient safety. This study provides evidence that virtual humans can be used in simulated critical incidents to assess the learning needs of health professionals, and provide important information that can inform the development of continuing education programs in patient safety. We explored the effectiveness of information transfer during a devolving medical situation between postanesthesia care unit (PACU) nurses and a virtual attending physician. Methods: We designed a three‐stage scenario: tutorial, patient transfer, and critical incident. We developed 2 checklists to assess information transfer: Critical Patient Information and Interprofessional Communication Skills. All participants were videotaped; 2 raters reviewed all videos and assessed performance using the checklists. Results: Participants (n = 43) who completed all 3 stages scored 62.3% correct on critical patient information transfer and 61.6% correct on interprofessional communication skills. Almost 87% missed a fatal drug error. The checklists measured each item on a 1/0 (done/not) calculation. Additionally, no relationship was found between years of nursing experience and performance on either checklist. Discussion: The PACU nurses in this study did not consistently share critical information with an attending (virtual) physician during a critical incident, and most missed a fatal dosage error. These findings strongly suggest a crucial need for additional structured team training among practicing health care teams, and they demonstrate the utility of using virtual humans to simulate team members.

A Qualitative Evaluation of Behavior during Conflict with an Authoritative Virtual Human

This research explores the extent to which humans behave realistically during conflict with a virtual human occupying a position of authority. To this end, we created a virtual team to train nurses how to manage conflict in the operating room; the team’s virtual surgeon engages in reckless behavior that could endanger the safety of the team’s patient, requiring nurses to intervene and correct the virtual surgeon’s behavior. Results from post-hoc behavioral analysis and semi-structured interviews indicate that participants behaved realistically during conflict, as compared against existing behavioral frameworks. However, some participants reported perceiving their virtual teammates as strangers, which they felt may have caused them to behave differently than they would with their normal teammates.

Training Together: how another human Trainee's Presence affects Behavior during Virtual human- Based Team Training

Despite research showing that team training can lead to strong improvements in team performance, logistical difficulties can prevent team training programs from being adopted on a large scale. A proposed solution to these difficulties is the use of virtual humans to replace missing teammates. Existing research evaluating the use of virtual humans for team training has been conducted in settings involving a single human trainee. However, in the real world multiple human trainees would most likely train together. In this paper, we explore how the presence of a second human trainee can alter behavior during a medical team training program. Ninety-two nurses and surgical technicians participated in a medical training exercise, where they worked with a virtual surgeon and virtual anesthesiologist to prepare a simulated patient for surgery. The agency of the nurse and the surgical technician were varied between three conditions: human nurses and surgical technicians working together; human nurses working with a virtual surgical technician; and human surgical technicians working with a virtual nurse. Variations in agency did not produce statistically significant differences in the training outcomes, but several notable differences were observed in other aspects of the teams behavior. Specifically, when working with a virtual nurse, human surgical technicians were more likely to assist with speaking up about patient safety issues that were outside of their normal responsibilities; human trainees spent less time searching for a missing item when working with a virtual partner, likely because the virtual partner was physically unable to move throughout the room and assist with the searching process; and more breaks in presence were observed when two human teammates were present. These results show that some behaviors may be influenced by the presence of multiple human trainees, though these behaviors may not impinge on core training goals. When developing virtual human-based training programs, designers should consider that the presence of other humans may reduce involvement during training moments perceived to be the responsibility of other trainees, and should consider that a virtual teammates limitations may cause human teammates to limit their own behaviors in corresponding ways (e.g. searching less).