Neurocritical Care Team

Karen Hirsch, MD
Associate Professor of Neurology and Neurological Sciences

Program Director, Neurocritical Care

Dr. Karen G. Hirsch joined the Stanford Stroke Center in 2012 as an Assistant Professor after completing neurology residency at the Johns Hopkins University and fellowship in neurocritical care at the University of California, San Francisco. She cares for critically ill patients with neurologic disorders in the intensive care unit and for patients with cerebrovascular disease in the inpatient stroke unit. Dr. Hirsch’s research focuses on novel imaging techniques such as functional brain imaging in patients with cardiac arrest and traumatic brain injury. She also studies methods of non-invasive measurement of cerebral blood flow, oxygenation, and cerebrovascular autoregulation and how these parameters might be targeted to improve outcome in patients with neurologic injury. In the outpatient clinic, she sees patients with head injury, stroke and other neurovascular diseases in addition to patients who have been discharged from the neurological intensive care unit.


Marion S. Buckwalter, MD, PhD
Associate Professor of Neurology and Neurological Sciences, and Neurosurgery

Dr. Buckwalter joined the Stroke Center in 2002 after her fellowship training at University of California San Francisco. Specialty trained in both neurocritical care and stroke, she oversees the care of patients who are neurologically critically ill. She also maintains a basic science laboratory at Stanford. Her lab focuses on how inflammatory responses after brain injury affect neurological recovery. In the United States, there are 4 million people currently living with the effects of stroke, and another 4.3 million living with the effects of traumatic brain injury. Of the people who have had a stroke, many are disabled to the degree that they cannot work, and a significant proportion are unable to walk, feed themselves, or communicate with their families the way they could prior to their stroke. Despite this very high number of people who are suffering, there is a large knowledge gap regarding the mechanisms by which neurological recovery occurs, and not a single FDA-approved therapy available to help people recover. There is reason to think that such a therapy might be obtainable - we know that some people, especially younger ones, experience significant recovery after stroke. Animal studies, almost entirely done in young animals, also demonstrate significant recovery after neurological injury. Dr. Buckwalter's goal is thus to better understand the mechanisms that contribute to recovery in the young, and how they are influenced by inflammatory responses. With better knowledge of these responses, she hopes to be able to develop new therapies that will help people recover better from stroke and other brain injuries.


Anna Finley Caulfield, MD
Clinical Associate Professor of Neurology and Neurological Sciences

Dr. Finley Caulfield joined the Stanford Stroke Center in 2004 from Beth Israel Deaconess Medical Center in Boston. She is specialty-trained both in stroke and neurocritical care. She cares for acute stroke patients and other neurologically critical ill patients in the intensive care unit. Currently, her research interests include hypothermia after cardiac arrest and comparing health care provider's predications of future neurological function in neurologically critical ill patients to their 6-month outcome.


Prashanth Krishnamohan, MD
Clinical Assistant Professor of Neurology & Neurological Sciences
Medical Director of Neurology, Stanford Health Care ValleyCare

Dr. Krishnamohan joined the Stanford Stroke Center as a Fellow in Neurocritical Care and Stroke in 2015 after completing an Internal Medicine residency in India and Neurology residency at the University of Kentucky. His clinical focus is on caring for patients with neurological illnesses in the intensive care unit. His research interest focuses on identifying predictors of brain injury severity after cardiac arrest. He is also the Medical Director of Neurology at Stanford Healthcare ValleyCare hospital where he is involved in building and expanding the Neurology program and also cares for hospitalized patients with acute strokes and other neurological diseases.


Zachary David Threlkeld, MD
Clinical Assistant Professor of Neurology and Neurological Sciences

Dr. Threlkeld cares for critically ill patients with acute neurologic illness, including traumatic brain injury, stroke, intracerebral hemorrhage, and epilepsy. He completed his residency training in neurology at the University of California, San Francisco, and joined the Stanford Neurocritical Care program after completing fellowship training in neurocritical care at Massachusetts General Hospital and Brigham and Women’s Hospital in Boston. He has a particular clinical and research interest in traumatic brain injury. His research uses advanced imaging modalities like functional magnetic resonance imaging (fMRI) to better understand disorders of consciousness.


Chitra Venkatasubramanian MBBS, MD, MSc, FNCS
Division of Stroke and Neurocritical Care
Clinical Professor, Department of Neurology and (by courtesy) Neurosurgery

Dr. Venkatasubramanian is a board certified vascular neurologist and neurointensivist who joined the Stanford Stroke Center in 2005 as a Fellow after completing successive residency training in internal medicine and neurology at Stanford University Medical Center. She also holds a Masters degree in Clinical Trials from LSHTM, University of London and is a board certified neurosonologist. She has been on faculty since 2007.  Her primary focus is the clinical care of neurologically critically ill patients in the intensive care unit and patients with acute stroke and TIA in the inpatient stroke unit. In addition, she sees patients with stroke and neurovascular diseases in her stroke clinic and patients discharged from the neurological ICU for follow up.

She is the Stanford prinicipal investigator for several clinical trials in intracerebral hemorrhage, large hemispheric infarction and fever management in brain injury. She also spearheads protocol development and quality improvement in the areas of emergency anticoagulation reversal, hypothermia after cardiac arrest, brain death and organ donation and pre-hospital neurocritical care for Lifeflight transport. She is keenly interested in the introduction of novel technologies in the ICU for delivering cutting edge neurocritical care.


APP Team

Jesus (Jay) Navoa, PA-C
Physician Assistant, Lead Advanced Practice Provider for the Inpatient Neurosciences

Jay graduated with a bachelor’s Degree in biology from Stony Brook University and continued his Physician Assistant education at St. John’s University in NY. He has over 13 years of neurosurgery and neurocritical care experience at Mount Sinai and Cornell-New York Presbyterian Hospitals and currently has been with Stanford since relocating to the west coast in 2016. He also has an additional year of thoracic surgery experience at Georgetown University Hospital. While at NYP, he helped in expanding the roles of the advanced practice providers in the neurosciences by assisting in the development of service line coverage in neurosurgery, general and vascular neurology and in neurocritical care. Jay currently oversees the advanced practice providers in both neurocritical care and inpatient neurosurgery and provides care for patients in both service lines.

Natalie Boehm, FNP-BC

Natalie graduated from Saddleback College in Mission Viejo, CA. She began her career as a registered nurse in the critical care unit, where she worked for 6 years. While gaining experience as a critical care nurse, she earned her bachelors in nursing science at Vanguard University in Costa Mesa, CA and then a Masters in Nursing Science, Nurse Practitioner at University of California. She moved to the Bay Area where she began her nurse practitioner career as  a neurocritical care nurse practitioner at Regional Medical Center in San Jose. She has been at Stanford as part of the inpatient Neurosurgery team since the beginning of 2019 and also works per diem with the Neurocritical Care team.

Elizabeth Fox, MSN, ACNS-BC, AGACNP-BC, CCRN, FAHA
Advanced Practice Provider, Neurocritical Care

Liz is an Advanced Practice Provider with Neurocritical Care at Stanford Health Care, Palo Alto, California.  She is board certified as an Adult-Gerontology Acute Care Nurse Practitioner and Adult Clinical Nurse Specialist.  Liz has held prior roles focused on stroke program development.  She is a Fellow of the American Heart/Stroke Association and serves as a board member of the Stroke Council of the Cardiovascular and Stroke Nursing Board.  She is also a committee member and chair elect for the Advanced Practice Provider Committee of the Neurocritical Care Society.  Liz serves as an assistant clinical professor in the Acute Care Nurse Practitioner program at University of California San Francisco.

Heather Clark, MS, RN, AGACNP-BC
Neurocritical Care Nurse Practitioner

Heather joined the Neurocritical Care service in 2017 as an APP after working for almost 3 years in cardiac surgery at Stanford.  She attended the University of Massachusetts Amherst for her undergraduate nursing degree and the University of California San Francisco for graduate school. She has been board certified as an Adult- Gerontology Acute Care Nurse Practitioner since 2014. Her clinical experience includes trauma, cardiac, medical, surgical, neurologic and neurosurgical ICUs over the last 15 years.

Angie Murkins, FNP-BC
Neurocritical Care Nurse Practictioner

Angie received her nursing degree from St. Luke’s College in Kansas City, MO and as a nurse practitioner from the University of Kansas School of Nursing in 2008. She previously worked in the CDU here at Stanford and has experience with the inpatient neurosurgery at Harborview Medical Center in Seattle, WA. She started with the neurosurgery team in 2017 and has since transitioned to caring for patients primarily on the neurocritical care service.