Browsing by Author "Chen, Andy W."

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    Intraoperative Tension Pneumothorax in a Trauma Patient: An Adult Simulation Case for Anesthesia Residents
    (MDPI, 2022-06-16) Okano, David Ryusuke; Chen, Andy W.; Mitchell, Sally A.; Cartwright, Johnny F.; Moore, Christopher; Anesthesia, School of Medicine
    Anesthesiologists may encounter multiple obstacles in communication when attempting to collect information for emergency surgeries. Occult tension pneumothorax that was asymptomatic in the emergency department (ED) could become apparent upon positive pressure ventilation and pose a critical threat to the patient intraoperatively. Here, we describe a simulation exercise that was developed as a curriculum module for the Indiana University (IU) Anesthesiology residency program. It is primarily designed for first-year clinical anesthesia residents (CA-1/PGY-2). It is a 50 min encounter with two scenarios. The first scenario focuses on information collection and communication with a non-cooperative patient with multiple distractors. The second scenario focuses on the early diagnosis of tension pneumothorax and subsequent treatment. The residents were given formative feedback and met the educational objectives. Commonly missed critical actions included misdiagnosing the tension pneumothorax as mainstem intubation, bronchospasm, pulmonary thromboembolism, and anaphylaxis. Residents rated the feedback and debriefing as "extremely useful" or "very useful." Time constraints limit the number of residents who can sit in the "hot seat." The structure of the mannequin limits the ability to diagnose pneumothorax by auscultation and ultrasound. In the future, the scenarios may also be utilized to educate student anesthesiologist assistants and other non-physician anesthesia learners.
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    Intraoperative Tension Pneumothorax in a Trauma Patient: An Adult Simulation Case for Anesthesia Residents
    (2022-09-17) Chen, Andy W.; Okano, David R.; Mitchell, Sally A.; Cartwright, Johnny F.; Moore, Christopher; Boyer, Tanna J.
    Introduction: Anesthesiologists may encounter multiple obstacles in communication when attempting to collect information for emergency surgeries. Occult tension pneumothorax that was asymptomatic in the Emergency Department (ED) could become apparent upon positive pressure ventilation and pose a critical threat to the patient intraoperatively. Methods: This simulation is primarily designed to train first-year of clinical anesthesia (CA-1) residents. It is designed as a 50-minute encounter consisting of 2 scenes. The first scene focuses on information collection and communication with a non-cooperative patient with multiple distractors. The second scene focuses on the early diagnosis of tension pneumothorax and the treatment. Results: This scenario has been developed as one of the regular simulation trainings at our facility. We tried to keep the simulation environment as realistic as possible. We did not grade the learners based on their performance, although most of the residents met the educational objectives. Commonly missed critical actions included misdiagnosing the tension pneumothorax as mainstem intubation, bronchospasm, pulmonary thromboembolism, or anaphylaxis. All residents learned from this scenario, as they rated the feedback and debriefing as “extremely useful” or “very useful.” Discussion: Our simulation program helps anesthesia residents develop crisis management skills for perioperative incidents in a safe environment, as well as to foster excellent communication skills. Time constraints limit the number of the residents who can sit in the “hot seat.” The structure of the mannequin often limits the ability to diagnose pneumothorax by auscultation. The scenarios can be also employed to educate student anesthesia assistants in the future.
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    Perioperative Anesthetic Considerations for Anti-NMDA Receptor Encephalitis Patients: A Case Report
    (2022-09-17) Chen, Andy W.; Axe, Michelle R.; Boyer, Tanna J.
    Introduction: Anti-NDMA receptor (anti-NMDA-R) encephalitis is a neurologic autoimmune disease that presents with characteristic psychiatric, neurological, and constitutional symptoms. It is caused by production of anti-NMDA-R antibodies, which in turn cause downregulation of NMDA receptors on central neurons. Detection of anti-NMDA-R antibodies in the serum or cerebrospinal fluid (CSF) confirms the diagnosis. The disease is often associated with an underlying tumor, most commonly an ovarian teratoma. Perioperative anesthetic management of patients with anti-NMDA-R encephalitis is a subject of interest to anesthesiologists because many anesthetic agents interact with the NMDA receptor, and therefore pose a risk of worsening the patient’s encephalitis, especially if surgical removal of the underlying teratoma is required for treatment. Case Description: A 15-year-old male diagnosed with anti-NMDA-R encephalitis in April 2022 was taken to the operating room (OR) for G-tube placement under general anesthesia in June 2022. The procedure followed a month-long hospitalization in the ICU and a month-long stay in the inpatient rehabilitation unit, all at Riley Children’s Hospital in Indianapolis, IN. The procedure was performed with total intravenous (IV) anesthesia with midazolam, dexmedetomidine, and remifentanil. Other medications the patient received during the procedure include cefazolin, dexamethasone, ondansetron, and ketorolac. Neither propofol nor volatile anesthetics were administered during the case. The patient remained hemodynamically stable intraoperatively with an uneventful postoperative course. Discussion: There is currently no definitive consensus on the optimal anesthetic regimen for patients with anti-NMDA-R encephalitis. In the available literature on this subject, both ketamine and nitrous oxide (N2O) have been routinely avoided because they are well-known for their direct NMDA-R antagonist activity. Commonly used agents include propofol, volatile anesthetics (e.g. sevoflurane), opioids, nondepolarizing paralytics, dexmedetomidine, and benzodiazepines (e.g. midazolam). Notably, volatile anesthetics (e.g. sevoflurane) and propofol are known to have some inhibitory activity on NMDA receptors, with volatile anesthetics demonstrating this moreso than propofol. Furthermore, there is some data to suggest that use of volatile anesthetics in these patients is associated with higher rates of postoperative adverse events, namely hypoventilation (potentially requiring reintubation) as well as pneumonia (e.g. aspiration pneumonia and ventilator-associated pneumonia). However, other studies and reviews have also reported no postoperative adverse events in the setting of volatile anesthetic use. A number of authors advocate for the use of midazolam, dexmedetomidine, and opioids, as these agents do not interact with NMDA receptors. Although there are no known reports of IV opioid-induced hypoventilation postoperatively in anti-NMDA-R encephalitis patients (to our knowledge), opioids still ought to be used judiciously in these patients, as they are at elevated risk of hypoventilation due to involvement of the brainstem respiratory center by the primary disease process.