- Critical Care Medicine
- Cardiothoracic Anesthesiology
- Extracorporeal Membrane Oxygenation
- Critical Care Ultrasonography
- Quality Improvement
Clinical Assistant Professor, Anesthesiology, Perioperative and Pain Medicine
Program Director, Anesthesiology Critical Care Medicine Fellowship, Stanford University School of Medicine (2024 - Present)
Director, Critical Care Ultrasonography, Stanford University School of Medicine (2021 - 2024)
Honors & Awards
ACTA Fellowship Teaching Award, Adult Cardiothoracic Anesthesiology Fellowship Program, Stanford University School of Medicine (2023)
ACTA Fellowship Teaching Award, Adult Cardiothoracic Anesthesiology Fellowship Program, Stanford University School of Medicine (2022)
John Silvey Thompson III, MD Memorial Critical Care Medicine Fellowship Award, Department of Anesthesiology, Perioperative and Pain Medicine (2020)
Frank H. Sarnquist Recognition Award, Department of Anesthesiology, Perioperative and Pain Medicine (2019)
Best case presentation (second prize), Western Anesthesia Regional Conference (2018)
Best presentation in category “Perioperative Challenges and Emergencies”, Western Anesthesia Regional Conference (2016)
TRANSFORM Patient Safety Program Award, Stanford Hospital & Clinics (April 2015)
TRANSFORM Patient Safety Program Award, Stanford Hospital & Clinics (September 2014)
Best Educational Abstract, Department of Anesthesiology, Perioperative, and Pain Medicine (2014)
George M.L. Sommerman Engineering Graduate Student Teaching Assistant Award, Johns Hopkins University (2010)
Center for Leadership Education Teaching Assistant Award of the Year, Johns Hopkins University (2008)
Richard J. Jones Outstanding Academic Achievement Award in Biomedical Engineering, Johns Hopkins University (2008)
Board Certification, American Board of Anesthesiology, Adult Cardiac Anesthesia (2024)
Board Certification, National Board of Echocardiography, Advanced Perioperative Transesophageal Echocardiography (2021)
Board Certification: National Board of Echocardiography, Critical Care Echocardiography (2020)
Board Certification: American Board of Anesthesiology, Critical Care Medicine (2020)
Board Certification: American Board of Anesthesiology, Anesthesia (2020)
Board Certification: American Board of Internal Medicine, Internal Medicine (2019)
Fellowship: Stanford University Anesthesiology Fellowships (2021) CA
Fellowship: Stanford University Critical Care Medicine Fellowship (2020) CA
Residency: Stanford University Anesthesiology Residency CA
Medical Education: Stanford University School of Medicine (2014) CA
MSE, Johns Hopkins University, Biomedical Engineering (2010)
BS, Johns Hopkins University, Biomedical Engineering (2008)
Additional Clinical Info
- Preparing for the Adult Cardiac Anesthesiology Subspecialty Certification: Recognition of Expertise in Cardiac Anesthesiology. Journal of cardiothoracic and vascular anesthesia 2023
Use of methylene blue to treat vasoplegia syndrome in cystic fibrosis patients undergoing lung transplantation: A case series.
Annals of cardiac anaesthesia
2023; 26 (1): 36-41
Several studies have demonstrated the utility of methylene blue (MB) to treat vasoplegic syndrome (VS), but some have cautioned against its routine use in lung transplantation with only two cases described in prominent literature. Cystic fibrosis patients commonly have chronic infections which predispose them to a systemic inflammatory syndrome-like vasoplegic response during lung transplantation. We present 13 cystic fibrosis patients who underwent lung transplantation and received MB for vasoplegic syndrome while on cardiopulmonary bypass, with or without inhaled pulmonary vasodilator therapy.Single-center, retrospective, case series analysis of cystic fibrosis patients who underwent lung transplant and received MB for vasoplegia. We defined the primary outcome as 30-day mortality, and secondary outcomes as primary graft failure, 1-year mortality, postoperative complications, and hemodynamic response to MB.MB was associated with a significant increase in mean arterial pressure (MAP) (P < 0.001) in all patients, and 84.6% (11/13) of the patients had either a decrease or no change in vasopressor requirement. No patients developed acute primary graft dysfunction and there was 100% 30-day and 1-year survival. One patient required Extracorporeal membrane oxygenation (ECMO) for hypoxemia and 69% (9/13) of the patients had evidence of postoperative right ventricular dysfunction, but no patients required a right ventricular assist device.This case series demonstrates the effectiveness of MB in treating vasoplegia in cystic fibrosis patients during lung transplantation, without evidence of primary graft dysfunction, 30-day or 1-year mortality. The safety of MB regarding hypoxemia and increased pulmonary vascular resistance requires further investigation.
View details for DOI 10.4103/aca.aca_276_20
View details for PubMedID 36722586
IMPACT OF C-REACTIVE PROTEIN ON ANTICOAGULATION MONITORING IN EXTRACORPOREAL MEMBRANE OXYGENATION
LIPPINCOTT WILLIAMS & WILKINS. 2023: 54
View details for Web of Science ID 000921450900108
Pheochromocytoma crisis precipitated by dexamethasone with profound lactic acidosis, but without severe hypertension.
Endocrinology, diabetes & metabolism case reports
Summary: We describe a case of a 47-year-old patient who presented with severe lactic acidosis, troponinemia, and acute kidney injury after receiving 8 mg of intramuscular dexamethasone for seasonal allergies in the setting of an undiagnosed epinephrine-secreting pheochromocytoma. This case was atypical, however, in that the patient exhibited only mildly elevated noninvasive measured blood pressures. Following a period of alpha-adrenergic blockade, the tumor was resected successfully. Steroid administration can precipitate pheochromocytoma crisis that may present unusually as in our patient with mild hypertension but profound lactic acidosis.Learning points: Steroids administered via any route can precipitate pheochromocytoma crisis, manifested by excessive catecholamine secretion and associated sequelae from vasoconstriction. Lack of moderate/severe hypertension on presentation detracts from consideration of pheochromocytoma as a diagnosis. Lactatemia after steroid administration should prompt work-up for pheochromocytoma, as it can be seen in epinephrine-secreting tumors. Noninvasive blood pressure measurements may be unreliable during pheochromocytoma crisis due to excessive peripheral vasoconstriction.
View details for DOI 10.1530/EDM-22-0306
View details for PubMedID 36511456
- Things We Do for No ReasonTM : Mandatory central venous catheter placement for initiation of vasopressors. Journal of hospital medicine 2022; 17 (7): 565-568
- SGLT-2 Inhibitors: Proliferating Indications and Perioperative Pitfalls. Journal of cardiothoracic and vascular anesthesia 2022
Unexpected Interruptions in the Inhaled Epoprostenol Delivery System: Incidence of Adverse Sequelae and Therapeutic Consequences in Critically Ill Patients.
Critical care explorations
2021; 3 (10): e0548
OBJECTIVES: Inhaled epoprostenol is a continuously delivered selective pulmonary vasodilator that is used in patients with refractory hypoxemia, right heart failure, and postcardiac surgery pulmonary hypertension. Published data suggest that inhaled epoprostenol administration via vibrating mesh nebulizer systems may lead to unexpected interruptions in drug delivery. The frequency of these events is unknown. The objective of this study was to describe the incidence and clinical consequences of unexpected interruption in critically ill patients.DESIGN: Retrospective review and analysis.SETTING: Stanford University Hospital, a 605-bed tertiary care center.PATIENTS: Patients receiving inhaled epoprostenol in 2019.INTERVENTIONS: No interventions.MEASUREMENTS AND MAIN RESULTS: Clinical indication, duration of inhaled epoprostenol delivery, mode of respiratory support, and documented unexpected interruption. In 2019, there were 493 administrations of inhaled epoprostenol in 433 unique patients. Primary indications for inhaled epoprostenol were right heart dysfunction (n = 394; 79.9%) and hypoxemia (n = 92; 18.7%). Unexpected delivery interruptions occurred in 31 administrations (6.3%). Median duration of therapy prior to unexpected interruption was 2 days (interquartile range, 2-5 d). Respiratory support at the time of unexpected interruption was mechanical ventilation (61.3%), high-flow nasal cannula (35.5%), and noninvasive positive pressure ventilation (3.2%). Adverse sequelae of unexpected interruption included elevated pulmonary artery pressures (n = 12), systemic hypotension (n = 8), hypoxemia (n = 8), elevated central venous pressure (n = 4), and cardiac arrest (n = 1). Therapeutic interventions following unexpected interruption included initiation of inhaled nitric oxide (n = 21), increase in vasoactive medication (n = 2), and increase in respiratory support (n = 2). Most of the adverse events were Common Terminology Criteria for Adverse Events grade 3 and 4 (93.5%).CONCLUSIONS: A retrospective review of patients receiving inhaled epoprostenol via vibrating mesh nebulizer in 2019 revealed interruptions in 6.3% of administrations with most of these interruptions requiring therapeutic intervention. The true incidence of unexpected interruption and subsequent rate of unexpected interruption's requiring intervention is unknown due to the reliance on unexpected interruption identification and subsequent documentation in the electronic medical record. Sudden interruption in inhaled epoprostenol delivery can result in severe cardiopulmonary compromise, and on rare occasion, death.
View details for DOI 10.1097/CCE.0000000000000548
View details for PubMedID 34671745
Death From Primary Amebic Meningoencephalitis After Recreational Water Exposure During Recent Travel to India-Santa Clara County, California, 2020.
Open forum infectious diseases
2021; 8 (8): ofab322
Background: In February 2020, a man returned to the United States after an 11-day trip to India and died of primary amebic meningoencephalitis (PAM), caused by nasal exposure to the free-living ameba Naegleria fowleri found in warm water. We identified potential exposures, confirmed etiology, and described the molecular epidemiology of the infection.Methods: We reviewed medical records to describe his clinical course and interviewed his family to determine water exposures. Genotyping was performed on the N. fowleri strain and compared with North American strains through repetitive nonpolymorphic nuclear loci analysis to identify differences. We reviewed N. fowleri strains in the National Center for Biotechnology Information database (GenBank) to determine genotypes present in India.Results: The patient became acutely encephalopathic 3 days after returning; the only known nasal water exposure was at an indoor swimming pool in India 5 days earlier. Cerebrospinal fluid (CSF) testing demonstrated neutrophil-predominant pleocytosis and low glucose, but negative gram stain and culture. CSF microscopy revealed trophozoites; N. fowleri was detected by real-time polymerase chain reaction. Classical genotyping confirmed genotype I, common in the United States and among Indian strains in GenBank. The North American N. fowleri strains and the patient's strain varied at 5 nonpolymorphic loci.Conclusions: A man died from PAM after likely exposure at a vacation rental pool in India. We recommend including PAM in the differential diagnosis when CSF studies suggest bacterial meningitis but gram stain is negative. Genotyping can advance our understanding of N. fowleri molecular epidemiology and support future investigations.
View details for DOI 10.1093/ofid/ofab322
View details for PubMedID 34395708
Perioperative Implications of the 2020 American Heart Association Scientific Statement on Drug-Induced Arrhythmias-A Focused Review.
Journal of cardiothoracic and vascular anesthesia
The recently released American Heart Association (AHA) scientific statement on drug-induced arrhythmias discussed medications commonly associated with bradycardia, supraventricular tachycardias, and ventricular arrhythmias. The foundational data for this statement were collected from general outpatient and inpatient populations. Patients undergoing surgical and minimally invasive treatments are a unique subgroup, because they may experience hemodynamic changes associated with anesthesia and their procedure, receive multiple drug combinations not given in either inpatient or outpatient settings, or experience postprocedural inflammatory syndromes. Accordingly, the generalizability of the AHA scientific statement to this perioperative population is unclear. This focused review highlights important aspects of the new AHA scientific statement and their application to the perioperative setting. The authors review medications frequently encountered and given by anesthesiologists and their risk of drug-induced arrhythmias and discuss common anesthetic and adjunctive medications and their associated risks of bradycardia, atrial fibrillation, torsades de pointes, and drug-induced Brugada syndrome. In many instances, the risk of arrhythmia reported by the AHA scientific statement in the general population appeared to be higher than found in perioperative arenas. Furthermore, the authors discuss the arrhythmia risk of additional medications commonly ordered or administered by anesthesiologists that are not included in the AHA scientific statement. As patient and procedural complexity increases and novel anesthetic combinations propagate, further research and observational studies will be required to delineate further perioperative risks for drug-induced arrhythmia.
View details for DOI 10.1053/j.jvca.2021.05.008
View details for PubMedID 34144871
The Use of Factor Eight Inhibitor Bypass Activity (FEIBA) for the Treatment of Perioperative Hemorrhage in Left Ventricular Assist Device Implantation.
Journal of cardiothoracic and vascular anesthesia
OBJECTIVE: To test the hypothesis that factor eight inhibitor bypassing activity (FEIBA) can be used to control bleeding following left ventricular assist device (LVAD) implantation without increasing the 14-day composite thrombotic outcome of pump thrombus, ischemic cerebrovascular accidents, pulmonary embolism, and deep venous thrombosis.DESIGN: Retrospective cohort study.SETTING: Academic hospital.PARTICIPANTS: Three hundred nineteen consecutive patients who underwent LVAD implantation (December 1, 2009 to December 30, 2018).INTERVENTION: FEIBA administered to control perioperative hemorrhage.MEASUREMENTS AND MAIN RESULTS: The 82 patients (25.7%) in the FEIBA cohort had more risk factors for perioperative hemorrhage, such as lower preoperative platelet count (169 ± 66 v 194 ± 68 * 103/mL, p = 0.004), prior cardiac surgery (36.6% v 21.9%, p = 0.008), and longer cardiopulmonary bypass (CPB) time (100.3 v 75.2 minutes, p = 0.001) than the 237 controls. After 16.6 units (95% CI: 14.3-18.9) of blood products were given, 992 units (95% CI: 821-1163) of FEIBA were required to control bleeding in the FEIBA cohort. Compared to the controls, there were no differences in the 14-day composite thrombotic outcome (11.0% v 7.6%, p = 0.343) or mortality rate (3.7% v 1.3%, p = 0.179). Multivariate logistical regression identified preoperative international normalized ratio (odds ratio [OR]: 1.30, 95% CI: 1.04-1.62) and CPB time (OR: 1.11, 95% CI: 1.02-1.20) as risk factors for 14-day thrombotic events, but FEIBA usage was not associated with an increased risk.CONCLUSIONS: In this retrospective cohort study, the use of FEIBA (1,000 units, 13 units/kg) to control perioperative hemorrhage following LVAD implantation was not associated with increases in mortality or composite thrombotic outcome.
View details for DOI 10.1053/j.jvca.2021.04.030
View details for PubMedID 34034934
- Antithrombin in Extracorporeal Membrane Oxygenation: To Replenish or Not to Replenish? Critical care medicine 2021; 49 (4): e480–e481
THE SAFETY AND EFFICACY OF PERIOPERATIVE FEIBA AFTER LEFT VENTRICULAR ASSIST DEVICE IMPLANTATION
LIPPINCOTT WILLIAMS & WILKINS. 2021: 168
View details for Web of Science ID 000672597100323
First lung and kidney multi-organ transplant following COVID-19 Infection.
The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation
As the world responds to the global crisis of the COVID-19 pandemic an increasing number of patients are experiencing increased morbidity as a result of multi-organ involvement. Of these, a small proportion will progress to end-stage lung disease, become dialysis dependent, or both. Herein, we describe the first reported case of a successful combined lung and kidney transplantation in a patient with COVID-19. Lung transplantation, isolated or combined with other organs, is feasible and should be considered for select patients impacted by this deadly disease.
View details for DOI 10.1016/j.healun.2021.02.015
View details for PubMedID 34059432
A SYSTEMATIC REVIEW OF PALLIATIVE CARE IN MECHANICAL CIRCULATORY SUPPORT
LIPPINCOTT WILLIAMS & WILKINS. 2021: 391
View details for Web of Science ID 000672597101368
- POCUS for Visualization and Facilitation of Urinary Catheter Placement. POCUS journal 2020; 5 (2): 35-36
Rescue of Nimodipine-Induced Refractory Vasoplegia With Hydroxocobalamin in Subarachnoid Hemorrhage: A Case Report.
Critical care explorations
2020; 2 (10): e0205
Background: We report a case of refractory vasoplegia after nimodipine administration that was unresponsive to triple vasopressor therapy and was rescued by IV hydroxocobalamin.Case Summary: An 84-year-old male presented comatose from a subarachnoid hemorrhage and developed severe hypotension unresponsive to three vasopressors following a single dose of enteral nimodipine. Multisystem point-of-care ultrasonography ruled out alternate etiologies of shock, indicating that this was likely a vasoplegic state caused by nimodipine. We administered 5 grams of IV hydroxocobalamin over 15 minutes due to the possibility of impaired nitric oxide metabolism as the driver of vasoplegia. This led to immediate improvement in hemodynamics and rapid discontinuation of vasopressors. The patient experienced chromaturia but no other adverse effects due to hydroxocobalamin.Conclusions: Nimodipine administration is a standard practice for patients with aneurysmal subarachnoid hemorrhage to reduce unfavorable outcomes from cerebral vasospasm. Although mild hypotension is a common side effect of nimodipine, in rare cases, it may become profound, leading to refractory vasoplegia. There is no evidence-base for reversal agents for nimodipine-induced vasoplegia, and this case is the first to demonstrate successful use of hydroxocobalamin as a potential rescue therapy. We also propose an algorithm for treatment of vasoplegia with consideration of medications that act on nitric oxide-mediated vasodilation and their side-effect profiles.
View details for DOI 10.1097/CCE.0000000000000205
View details for PubMedID 33063021
- Rethinking sedation during prolonged mechanical ventilation for COVID-19 respiratory failure. Anesthesia and analgesia 2020
Mortality of Patients Requiring Escalation to Intensive Care within 24 Hours of Admission in a Mixed Medical-Surgical Population.
Clinical medicine & research
Delayed intensive care unit admissions are associated with increased mortality. We present a retrospective study looking at whether indirect admissions to the ICU within 24 hours of hospital admission were associated with increased mortality.Retrospective cohort study SETTING: Mixed medical-surgical ICU at a large tertiary United States Veterans Affairs (VA) Hospital System POPULATION: The patients were a mix of medical and surgical patients. Patients included both those directly admitted from the operating room as well as those escalated to the ICU after initial admission to the ward (indirect admission).All admissions to a medical-surgical ICU from 2008 to 2013 were included in the study. The database was queried for time and location where the admission originated. Separate lists were created for patients with severe sepsis, patients who transferred to the ICU within the first 24 hours, and patients who had rapid response or code team activations. Analysis was applied to the whole group and to medical and surgical subpopulations.A total of 3,862 ICU admissions were studied. Univariate analysis indicated an impact of delayed admission on whole group and surgical patients, however multivariate analysis indicated a significant effect of delayed admission on 1-year surgical mortality. Multivariate analysis also showed a consistent effect of age, ICU length of stay and cardiac arrest on mortality of both medical and surgical ICU patients.In a large retrospective study, surgical patients had increased 1-year mortality if they required escalation to the ICU within 24 hours of hospital admission. This result was not replicated in medical patients, possibly related to a burden of illness that could not be altered by earlier care.
View details for DOI 10.3121/cmr.2019.1497
View details for PubMedID 31959671
Catecholamine-induced cerebral vasospasm and multifocal infarctions in pheochromocytoma.
Endocrinology, diabetes & metabolism case reports
We report the case of a 76-year-old male with a remote history of papillary thyroid cancer who developed severe paroxysmal headaches in the setting of episodic hypertension. Brain imaging revealed multiple lesions, initially of inconclusive etiology, but suspicious for metastatic foci. A search for the primary malignancy revealed an adrenal tumor, and biochemical testing confirmed the diagnosis of a norepinephrine-secreting pheochromocytoma. Serial imaging demonstrated multiple cerebral infarctions of varying ages, evidence of vessel narrowing and irregularities in the anterior and posterior circulations, and hypoperfusion in watershed areas. An exhaustive work-up for other etiologies of stroke including thromboembolic causes or vasculitis was unremarkable. There was resolution of symptoms, absence of new infarctions, and improvement in vessel caliber after adequate alpha-adrenergic receptor blockade for the management of pheochromocytoma. This clinicoradiologic constellation of findings suggested that the etiology of the multiple infarctions was reversible cerebral vasoconstriction syndrome (RCVS). Pheochromocytoma remains a poorly recognized cause of RCVS. Unexplained multifocal cerebral infarctions in the setting of severe hypertension should prompt the consideration of a vasoactive tumor as the driver of cerebrovascular dysfunction. A missed or delayed diagnosis has the potential for serious neurologic morbidity for an otherwise treatable condition.The constellation of multifocal watershed cerebral infarctions of uncertain etiology in a patient with malignant hypertension should trigger the consideration of undiagnosed catecholamine secreting tumors, such as pheochromocytomas and paragangliomas. Reversible cerebral vasoconstriction syndrome is a serious but reversible cerebrovascular manifestation of pheochromocytomas that may lead to strokes (ischemic and hemorrhagic), seizures, and cerebral edema. Alpha-adrenergic receptor blockade can reverse cerebral vasoconstriction and prevent further cerebral ischemia and infarctions. Early diagnosis of catecholamine secreting tumors has the potential for reducing neurologic morbidity and mortality in patients presenting with cerebrovascular complications.
View details for DOI 10.1530/EDM-20-0078
View details for PubMedID 32820130
DUAL TRAINING IN ANESTHESIOLOGY AND INTERNAL MEDICINE: SYNERGISTIC PATHWAY TO CRITICAL CARE MEDICINE
LIPPINCOTT WILLIAMS & WILKINS. 2020
View details for Web of Science ID 000530000201468
Retrospective Analysis of Peri-Intubation Hypoxemia During the Coronavirus Disease 2019 Epidemic Using a Protocol for Modified Airway Management.
2020; 14 (14): e01360
This single-center retrospective study evaluated a protocol for the intubation of patients with confirmed or suspected coronavirus disease 2019 (COVID-19). Twenty-one patients were intubated, 9 of whom were found to have COVID-19. Adherence to the airway management protocol was high. COVID-19 patients had lower peripheral capillary oxygen saturation by pulse oximetry (Spo2) nadirs during intubation (Spo2, 73% [72%-77%] vs 89% [86%-94%], P = .024), and a greater percentage experienced severe hypoxemia defined as Spo2 ≤80% (89% vs 25%, P = .008). The incidence of severe hypoxemia in COVID-19 patients should be considered in the development of guidelines that incorporate high-flow nasal cannula and noninvasive positive pressure ventilation.
View details for DOI 10.1213/XAA.0000000000001360
View details for PubMedID 33449537
- Traumatic Pneumothorax Presenting as a Subcutaneous "Airball". American journal of respiratory and critical care medicine 2020
Anesthetic Considerations for Liver Transplantation in a Patient with Mitochondrial Neurogastrointestinal Encephalopathy Syndrome.
2019; 11 (6): e5038
Mitochondrial neurogastrointestinal encephalopathy (MNGIE) is a rare, complex mitochondrial disorder with variable phenotypes caused by a defect in the TYMP gene that codes for the thymidine phosphorylase enzyme. Orthotopic liver transplantation (OLT) has been proposed as a curative option for patients by using the liver as a source to restore thymidine phosphorylase levels in the body. Anesthetic considerations for this syndrome have not been clearly outlined in the past. We describe the clinical presentation of a young woman with MNGIE, her perioperative assessment, and intraoperative management during liver transplantation.
View details for DOI 10.7759/cureus.5038
View details for PubMedID 31501730
View details for PubMedCentralID PMC6721878
Curricular Innovations for Medical Students in Palliative and End-of-Life Care: A Systematic Review and Assessment of Study Quality
JOURNAL OF PALLIATIVE MEDICINE
2015; 18 (4): 338-349
Recent focus on palliative and end-of-life care has led medical schools worldwide to enhance their palliative care curricula.The objective of the study was to describe recent curricular innovations in palliative care for medical students, evaluate the quality of studies in the field, and inform future research and curricular design.The authors searched Medline, Scopus, and Educational Resource Information Center (ERIC) for English-language articles published between 2007 and 2013 describing a palliative care curriculum for medical students. Characteristics of the curricula were extracted, and methodological quality was assessed using the Medical Education Research Study Quality Instrument (MERSQI).The sample described 48 curricula in 12 countries. Faculty were usually interdisciplinary. Palliative care topics included patient assessment, communication, pain and symptom management, psychosocial and spiritual needs, bioethics and the law, role in the health care system, interdisciplinary teamwork, and self-care. Thirty-nine articles included quantitative evaluation, with a mean MERSQI score of 9.9 (on a scale of 5 to 18). The domain most likely to receive a high score was data analysis (mean 2.51 out of 3), while the domains most likely to receive low scores were validity of instrument (mean 1.05) and outcomes (mean 1.31).Recent innovations in palliative care education for medical students represent varied settings, learner levels, instructors, educational modalities, and palliative care topics. Future curricula should continue to incorporate interdisciplinary faculty. Studies could be improved by integrating longitudinal curricula and longer-term outcomes; collaborating across institutions; using validated measures; and assessing higher-level outcomes including skills, behaviors, and impact on patient care.
View details for DOI 10.1089/jpm.2014.0270
View details for Web of Science ID 000351274500008
View details for PubMedID 25549065
Hypothermia Amplifies Somatosensory-evoked Potentials in Uninjured Rats
JOURNAL OF NEUROSURGICAL ANESTHESIOLOGY
2012; 24 (3): 197-202
Temperature fluctuations significantly impact neurological injuries in intensive care units. As the benefits of therapeutic hypothermia continue to unfold, many of these discoveries are generated by studies in animal models undergoing experimental procedures under the influence of anesthetics. We studied the effect of induced hypothermia on neural electrophysiological signals of an uninjured brain in a rodent model while under isoflurane. Fourteen rats were divided into 2 groups (n=7 each), on the basis of electrode placement at either frontal-occipital or primary somatosensory cortical locations. Neural signals were recorded during normothermia (T=36.5 to 37.5°C), mild hypothermia (T=32 to 34°C), and hyperthermia (T=38.5 to 39.5°C). The burst-suppression ratio was used to evaluate electroencephalography (EEG), and amplitude-latency analysis was used to assess somatosensory-evoked potentials (SSEPs). Hypothermia was characterized by an increased burst-suppression ratio (mean±SD) of 0.58±0.06 in hypothermia versus 0.16±0.13 in normothermia, P<0.001 in frontal-occipital; and 0.30±0.13 in hypothermia versus 0.04±0.04 in normothermia, P=0.006 in somatosensory. There was potentiation of SSEP (2.89±1.24 times the normothermic baseline in hypothermia, P=0.02) and prolonged peak latency (N10: 10.8±0.4 ms in hypothermia vs. 9.1±0.3 ms in normothermia; P15: 16.2±0.8 ms in hypothermia vs. 13.7±0.6 ms in normothermia; P<0.001), whereas hyperthermia was primarily marked by shorter peak latencies (N10: 8.6±0.2 ms, P15: 12.6±0.4 m; P<0.001). In the absence of brain injury in a rodent model, hypothermia induces significant increase to the SSEP amplitude while increasing SSEP latency. Hypothermia also suppressed EEGs at different regions of the brain by different degrees. The changes to SSEP and EEG are both reversible with subsequent rewarming.
View details for DOI 10.1097/ANA.0b013e31824ac36c
View details for Web of Science ID 000305272400005
View details for PubMedID 22441433
View details for PubMedCentralID PMC3372632
Study of the origin of short- and long-latency SSEP during recovery from brain ischemia in a rat model
2010; 485 (3): 157-161
Somatosensory evoked potentials (SSEPs) have been established as an electrophysiological tool for the prognostication of neurological outcome in patients with hypoxic-ischemic brain injury. The early and late responses in SSEPs reflect the sequential activation of neural structures along the somatosensory pathway. This study reports that the SSEP can be separated into early (short-latency, SL) and late (long-latency, LL) responses using independent component analysis (ICA), based on the assumption that these components are generated from different neural sources. Moreover, this source separation into the SL and LL components allows analysis of electrophysiological response to brain injury, even when the SSEPs are severely distorted and SL and LL components get mixed. With the help of ICA decomposition and corrected peak estimation, the latency of LL-SSEP is shown to be predictive of long-term neurological outcome. Further, it is shown that the recovery processes of SL- and LL-SSEPs follow different dynamics, with the SL-SSEP restored earlier than LL-SSEP. We predict that the SL- and LL-SSEPs reflect the timing of the progression of evoked response through the thalamocortical pathway and as such respond differently depending upon injury and recovery of the thalamic and cortical regions, respectively.
View details for DOI 10.1016/j.neulet.2010.08.086
View details for Web of Science ID 000284017400004
View details for PubMedID 20816917
View details for PubMedCentralID PMC2997340
Quantitative assessment of somatosensory-evoked potentials after cardiac arrest in rats: Prognostication of functional outcomes
CRITICAL CARE MEDICINE
2010; 38 (8): 1709-1717
High incidence of poor neurologic sequelae after resuscitation from cardiac arrest underscores the need for objective electrophysiological markers for assessment and prognosis. This study aims to develop a novel marker based on somatosensory evoked potentials (SSEPs). Normal SSEPs involve thalamocortical circuits suggested to play a role in arousal. Due to the vulnerability of these circuits to hypoxic-ischemic insults, we hypothesize that quantitative SSEP markers may indicate future neurologic status.Laboratory investigation.University Medical School and Animal Research Facility.: Sixteen adult male Wistar rats.None.SSEPs were recorded during baseline, during the first 4 hrs, and at 24, 48, and 72 hrs postasphyxia from animals subjected to asphyxia-induced cardiac arrest for 7 or 9 mins (n = 8/group). Functional evaluation was performed using the Neurologic Deficit Score (NDS). For quantitative analysis, the phase space representation of the SSEPs-a plot of the signal vs. its slope-was used to compute the phase space area bounded by the waveforms recorded after injury and recovery. Phase space areas during the first 85-190 mins postasphyxia were significantly different between rats with good (72 hr NDS >or=50) and poor (72 hr NDS <50) outcomes (p = .02). Phase space area not only had a high outcome prediction accuracy (80-93%, p < .05) during 85-190 mins postasphyxia but also offered 78% sensitivity to good outcomes without compromising specificity (83-100%). A very early peak of SSEPs that precedes the primary somatosensory response was found to have a modest correlation with the 72 hr NDS subscores for thalamic and brainstem function (p = .066) and not with sensory-motor function (p = .30).Phase space area, a quantitative measure of the entire SSEP morphology, was shown to robustly track neurologic recovery after cardiac arrest. SSEPs are among the most reliable predictors of poor outcome after cardiac arrest; however, phase space area values early after resuscitation can enhance the ability to prognosticate not only poor but also good long-term neurologic outcomes.
View details for DOI 10.1097/CCM.0b013e3181e7dd29
View details for Web of Science ID 000280116500011
View details for PubMedID 20526197
View details for PubMedCentralID PMC3050516
Evolution of somatosensory evoked potentials after cardiac arrest induced hypoxic-ischemic injury
2010; 81 (7): 893-897
We tested the hypothesis that early recovery of cortical SEP would be associated with milder hypoxic-ischemic injury and better outcome after resuscitation from CA.Sixteen adult male Wistar rats were subjected to asphyxial cardiac arrest. Half underwent 7min of asphyxia (Group CA7) and half underwent 9min (Group CA9). Continuous SEPs from median nerve stimulation were recorded from these rats for 4h immediately following CA, and at 24, 48, and 72h. Clinical recovery was evaluated using the Neurologic Deficit Scale.All rats in group CA7 survived to 72h, while only 50% of rats in group CA9 survived to that time. Mean NDS values in the CA7 group at 24, 48, and 72h after CA were significantly higher than those of CA9. The N10 (first negative potential at 10ms) amplitude was significantly lower within 1h after CA in rats that suffered longer CA durations. SEPs were also analyzed by separating the rats into good (NDS>or=50) vs. bad (NDS<50) outcomes at 72h, again showing significant difference in N10 and peak-to-peak amplitudes between the two groups. In addition, a smaller N7 potential was consistently observed to recover earlier in all rats.The diminished recovery of N10 is associated with longer CA times in rats. Higher N10 and peak-to-peak amplitudes during early recovery are associated with better neurologic outcomes. N7, which may represent thalamic activity, recovers much earlier than cortical responses (N10), suggesting failure of thalamocortical conduction during early recovery.
View details for DOI 10.1016/j.resuscitation.2010.03.030
View details for Web of Science ID 000279758500025
View details for PubMedID 20418008
View details for PubMedCentralID PMC2893290
Characterization of Neurologic Injury using Novel Morphological Analysis of Somatosensory Evoked Potentials
32nd Annual International Conference of the IEEE Engineering-in-Medicine-and-Biology-Society (EMBC 10)
IEEE. 2010: 2798–2801
This paper describes an innovative, easy-to-interpret, clinically translatable tool for analysis of Somatosensory Evoked Potentials (SSEPs). Unlike traditional analysis, which involves peak-to-peak amplitude and latency calculation, this method, phase space analysis, analyzes the overall morphology of the SSEP, and includes greater information. The SSEP is plotted in phase space (x-dot vs. x), which leads to an approximately spiral curve. The area swept out by this curve is termed the Phase Space Area (PSA). As PSA calculation involves numerical differentiation, we present a comparison of two different approaches to combat noise amplification: finite-window smoothing, and total variation regularization (TVR) of the numerical derivative. These methods are applied to simulated SSEPs. The efficacy of these methods in performing noise-reduction is assessed and compared with ensemble averaging. While TVR gives a reasonably robust approximation of the derivative, Gaussian smoothing of the derivative offers the best trade-off between the number of signal sweeps required to be averaged, close approximation of the SSEP derivative, and optimal estimation of the PSA. We validate this method by analyzing non-characteristic SSEPs that have indistinguishable peaks as is frequently seen in cases of underlying neurologic injury such as hypoxic-ischemic encephalopathy.
View details for Web of Science ID 000287964003051
View details for PubMedID 21095700
Discovery of Long-Latency Somatosensory Evoked Potentials as a Marker of Cardiac Arrest Induced Brain Injury
SPRINGER. 2010: 101–4
View details for Web of Science ID 000307744700027
EARLY INDICATION OF NEUROLOGICAL OUTCOMES AFTER CARDIAC ARREST USING QUANTITATIVE SOMATOSENSORY EVOKED POTENTIAL MONITORING
LIPPINCOTT WILLIAMS & WILKINS. 2009: A308
View details for Web of Science ID 000272509900599
Neural Signals in Cortex and Thalamus during Brain Injury from Cardiac Arrest in Rats
Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society
IEEE. 2009: 5946–5949
Previous research has shown that a characteristic burst-suppression (BS) pattern appears in EEG during the early recovery period following cardiac arrest (CA). To study cortical and subcortical neural activity underlying BS, extracellular activity in the parietal cortex and the centromedian nucleus of the thalamus and extradural EEG were recorded in a rodent CA model. Preliminary results show that during the BS, the cortical firing rate is extraordinarily high, and that bursts in EEG correlate to dense spikes in cortical neurons. An unexpected and novel observation is that 1) thalamic activity reappears earlier than cortical activity following CA, and 2) the correlation coefficient of cortical and thalamic activity rises during BS period. These results will help elucidate the mechanism of brain recovery after CA injury.
View details for Web of Science ID 000280543604212
View details for PubMedID 19965064
Honors Biomedical Instrumentation - A Course Model for Accelerated Design
Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society
IEEE. 2009: 2015–2018
A model for a 16-week Biomedical Instrumentation course is outlined. The course is modeled in such a way that students learn about medical devices and instrumentation through lecture and laboratory sessions while also learning basic design principles. Course material covers a broad range of topics from fundamentals of sensors and instrumentation, guided laboratory design experiments, design projects, and eventual protection of intellectual property, regulatory considerations, and entry into the commercial market. Students eventually complete two design projects in the form of a 'Challenge' design project as well as an 'Honors' design project. Sample problems students solve during the Challenge project and examples of past Honors projects from the course are highlighted.
View details for Web of Science ID 000280543601236
View details for PubMedID 19964766
Information Theoretical Assessment of Neural Spiking Activity with Temperature Modulation
Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society
IEEE. 2009: 4990–4993
Previous research has shown that hypothermia immediately after Cardiac Arrest (CA) improves neurological outcomes. In order to study how hypothermia affects neural spiking, cortical and subcortical neural activity was recorded from rodents. Consistent with previous findings, preliminary results show that the firing rate is proportional to the temperature. We also studied the information coded in the spike-timing information of individual neurons and observed that information content varies with temperature. Furthermore, there is an increased dependence between the cortex and sub-cortical structures such as the Thalamus during hypothermia. The latter is most likely an indicator of coupling between these highly connected structures in response to temperature manipulation leading to arousal after global cerebral ischemia.
View details for Web of Science ID 000280543603340
View details for PubMedID 19965028
Specific Considerations for Venovenous Extracorporeal Membrane Oxygenation During Coronavirus Disease 2019 Pandemic.
ASAIO journal (American Society for Artificial Internal Organs : 1992)
; 66 (10): 1069–72
Extracorporeal membrane oxygenation (ECMO) is recognized as organ support for potentially reversible acute respiratory distress syndrome (ARDS). However, limited resource during the outbreak and the coagulopathy associated with coronavirus disease 2019 (COVID-19) make the utilization of venovenous (VV) ECMO highly challenging. We herein report specific considerations for cannulation configurations and ECMO management during the pandemic. High blood flow and anticoagulation at higher levels than usual practice for VV ECMO may be required because of thrombotic hematologic profile of COVID-19. Among our first 24 cases (48.8 ± 8.9 years), 17 patients were weaned from ECMO after a mean duration of 19.0 ± 10.1 days and 16 of them have been discharged from ICU.
View details for DOI 10.1097/MAT.0000000000001251
View details for PubMedID 33136589