Article Data

  • Views 868
  • Dowloads 377


Open Access Special Issue

Clinical approach to coma patients: tips and tricks

  • Winchana Srivilaithon1
  • Sombat Muengtaweepongsa2

1Department of Emergency Medicine, Faculty of Medicine, Thammasat University, 12120 Klong Luang, Pathum Thani, Thailand

2Center of Excellence in Stroke, Faculty of Medicine, Thammasat University, 12120 Klong Luang, Pathum Thani, Thailand

DOI: 10.22514/sv.2021.230

Submitted: 23 May 2021 Accepted: 29 July 2021

Online publish date: 11 November 2021

*Corresponding Author(s): Sombat Muengtaweepongsa E-mail:


The reticular activating system (RAS) is responsible for wakefulness. The RAS projects activation to either side of the hemisphere. The dysfunction of the RAS or insufficiency of its activation results in impairment of consciousness. Physicians classify levels of awareness into four levels, from normal status to most severe unconsciousness, these being alert, drowsy, stupor, and coma, respectively. While the causes of unconsciousness are varied, physicians generally divide them into structural and metabolic etiologies upon the dominant approach. Surgical management is the primary treatment for the structural coma, while the metabolic coma requires predominantly medical treatment. The diagnosis and management of unconscious patients require extensive clinical assessment, consisting of a careful approach to history-taking and general medical and neurological examinations. Following immediate resuscitation by the ABCDE approach and proper management protocols, physicians should look for causes of loss of consciousness through clinical evidence and investigations. Appropriate management will help to avoid secondary complications related to the impairment of consciousness. The prognostication of a coma is also varied and primarily depends on its etiology. The algorithm for prognostication in a coma is helpful for poor outcome determinants.


Coma; Unconsciousness; Glasgow coma scale; Prognostication

Cite and Share

Winchana Srivilaithon,Sombat Muengtaweepongsa. Clinical approach to coma patients: tips and tricks. Signa Vitae. 2021.doi:10.22514/sv.2021.230.


[1] Morin A. Levels of consciousness and self-awareness: a comparison and integration of various neurocognitive views. Consciousness and Cognition. 2006; 15: 358–371.

[2] Arguinchona JH, Tadi P. Neuroanatomy, Reticular Activating System. StatPearls Publishing: Treasure Island. 2021.

[3] Yeo SS, Chang PH, Jang SH. The Ascending Reticular Activating System from Pontine Reticular Formation to the Thalamus in the Human Brain. Frontiers in Human Neuroscience. 2013; 7: 416.

[4] Parvizi J. Consciousness and the brainstem. Cognition. 2001; 79: 135–160.

[5] Newman JB, Banks WP, Baars BJ. Essential Sources in the Scientific Study of Consciousness. Cambridge, Mass: A Bradford Book. 2003.

[6] Terlouw C, Bourguet C, Deiss V. Consciousness, unconsciousness and death in the context of slaughter. Part I. Neurobiological mechanisms underlying stunning and killing. Meat Science. 2016; 118: 133–146.

[7] Blumenfeld H. Neuroanatomical Basis of Consciousness. The Neurology of Conciousness. 2016; 33: 3–29.

[8] Ropper AH. Coma. In: Kasper D, Fauci A, Hauser S, Longo D, Jameson JL, Loscalzo J. Harrison’s Principles of Internal Medicine. McGraw-Hill Education: New York, NY. 2015.

[9] Bates D. Coma and brain stem death. Medicine. 2008; 36: 601–608.

[10] Hemphill JC. Disorders of Consciousness in Systemic Diseases. Aminoff’s Neurology and General Medicine. 2014; 137: 1243–1261.

[11] Encyclopædia Britannica. Britannica Academic. Available at: (Accessed: 3 De-cember 2017).

[12] Simon RP, Aminoff MJ, Greenberg DA. Coma. Clinical Neurology. McGraw-Hill Education: New York, NY. 2017.

[13] Kemp WL, Burns DK, Brown TG. Chapter 11. Neuropathology. Pathology: The Big Picture. The McGraw-Hill Companies: New York, NY. 2008.

[14] Horsting MWB, Franken MD, Meulenbelt J, van Klei WA, de Lange DW. The etiology and outcome of non-traumatic coma in critical care: a systematic review. BMC Anesthesiology. 2015; 15: 65.

[15] Edlow JA, Rabinstein A, Traub SJ, Wijdicks EFM. Diagnosis of reversible causes of coma. Lancet. 2014; 384: 2064–2076.

[16] Trübel HK, Novotny E, Lister G. Outcome of coma in children. Current Opinion in Pediatrics. 2003; 15: 283–287.

[17] Wong CP, Forsyth RJ, Kelly TP, Eyre JA. Incidence, aetiology, and outcome of non-traumatic coma: a population based study. Archives of Disease in Childhood. 2001; 84: 193–199.

[18] Seshia SS, Bingham WT, Kirkham FJ, Sadanand V. Nontraumatic coma in children and adolescents: diagnosis and management. Neurologic Clinics. 2011; 29: 1007–1043.

[19] Greer DM, Yang J, Scripko PD, Sims JR, Cash S, Kilbride R, et al. Clinical examination for outcome prediction in nontraumatic coma. Critical Care Medicine. 2012; 40: 1150–1156.

[20] Weiss N, Regard L, Vidal C, Luque Y, Taldir G, Vallet H, et al. Causes of coma and their evolution in the medical intensive care unit. Journal of Neurology. 2012; 259: 1474–1477.

[21] Zammit C, Choi KE, Rosengart A. Principles of Neurosciences Critical Care. In: Oropello JM, Pastores SM, Kvetan V (ed.) Critical Care. McGraw-Hill Education: New York, NY. 2016.

[22] Kasper DL, Fauci AS, Hauser SL, Longo DL, Jameson JL, Loscalzo J. Confusion, Stupor, and Coma. Harrison’s Manual of Medicine. McGraw-Hill Education: New York, NY. 2016.

[23] Durcan L. Coma and Disorders of Consciousness. In: McKean SC, Ross JJ, Dressler DD, Scheurer DB (ed.) Principles and Practice of Hospital Medicine. McGraw-Hill Education: New York, NY. 2017.

[24] Kislitsina ON, Rich JD, Wilcox JE, Pham DT, Churyla A, Vorovich EB, et al. Shock – Classification and Pathophysiological Principles of Therapeutics. Current Cardiology Reviews. 2019; 15: 102–113.

[25] Olson KR. Poisoning. In: Papadakis MA, McPhee SJ, Rabow MW (ed) Current Medical Diagnosis & Treatment 2017. McGraw-Hill Education: New York, NY. 2016.

[26] Masharani U. Diabetes Mellitus & Hypoglycemia. In: Papadakis MA, McPhee SJ, Rabow MW (ed) Current Medical Diagnosis & Treatment 2018. McGraw-Hill Education: New York, NY. 2017.

[27] Mihic SJ, Koob GF, Mayfield J, Harris RA. Ethanol. In: Brunton LL, Hilal-Dandan R, Knollmann BC (ed) Goodman & Gilman’s: The Pharmacological Basis of Therapeutics. McGraw-Hill Education: New York, NY. 2017.

[28] Ghany MG, Hoofnagle JH. Approach to the Patient with Liver Disease. In: Kasper D, Fauci A, Hauser S, Longo D, Jameson JL, Loscalzo J (ed) Harrison’s Principles of Internal Medicine. McGraw-Hill Education: New York, NY. 2015.

[29] Ropper AH, Samuels MA, Klein JP. Chapter 17. Coma and Related Disorders of Consciousness. Adams and Victor’s Principles of Neurology. 10th edn. The McGraw-Hill Companies: New York, NY. 2014.

[30] Olson KR, Anderson IB, Benowitz NL, Blanc PD, Clark RF, Kearney TE, et al. Comprehensive Evaluation and Treatment. Poisoning & Drug Overdose. 7th edn. McGraw-Hill Education: New York, NY. 2017.

[31] Santistevan J, Long B, Koyfman A. Rash Decisions: an Approach to Dangerous Rashes Based on Morphology. The Journal of Emergency Medicine. 2017; 52: 457–471.

[32] Tan J, Fedi M. Clinical approach to comatose patients. Anaesthesia & Intensive Care Medicine. 2016; 17: 607–610.

[33] Greer DM, Yang J, Scripko PD, Sims JR, Cash S, Wu O, et al. Clinical examination for prognostication in comatose cardiac arrest patients. Resuscitation. 2013; 84: 1546–1551.

[34] Grmec Š, Gašparovic V. Comparison of APACHE II, MEES and Glasgow Coma Scale in patients with nontraumatic coma for prediction of mortality. Critical Care. 2001; 5: 19.

[35] Barlow P. A practical review of the Glasgow Coma Scale and Score. The Surgeon. 2012; 10: 114–119.

[36] Sternbach GL. The Glasgow Coma Scale11Medical Classics is coordi-nated by George Sternbach, MD, of Stanford University Medical Center, Stanford, California. The Journal of Emergency Medicine. 2000; 19: 67–71.

[37] Teasdale G, Maas A, Lecky F, Manley G, Stocchetti N, Murray G. The Glasgow Coma Scale at 40 years: standing the test of time. The Lancet Neurology. 2014; 13: 844–854.

[38] McClintic MM, Horrall SD. Coma. In: Stone CK, Humphries RL (ed.) CURRENT Diagnosis & Treatment: Emergency Medicine. 8th edn. New York, NY: McGraw-Hill Education. 2017.

[39] Bajekal R, Bari F. Eye signs in anaesthesia and intensive care medicine. Anaesthesia & Intensive Care Medicine. 2017; 18: 44–46.

[40] Wilhelm H. Disorders of the pupil. Handbook of Clinical Neurology. 2011; 102: 427–466.

[41] Berger JR. CHAPTER 13: Coma. Clinical Adult Neurology (pp. 213–227). Demos Medical Publishing, LLC.: New York. 2009.

[42] Pullen RL. Clinical do’s & don’ts. Checking for oculocephalic reflex. Nursing. 2005; 35: 24.

[43] Rzewnicki I, Łebkowski W, Kordecki JK. Evaluation of vestibulo-ocular reflex in patients with damage to the central nervous system (GCS score 5–3). Advances in Medical Sciences. 2015; 60: 107–111.

[44] Greer DG, Donofrio PD. CHAPTER 16 - Electrophysiological Evalua-tions. In: Dobbs MR (ed) Clinical Neurotoxicology (201–212.). W.B. Saunders: Philadelphia. 2009.

[45] Howard RS. Coma and brainstem death. Medicine. 2012; 40: 500–506.

[46] Cooksley T, Holland M. The management of coma. Medicine. 2017; 45: 115–119.

[47] Thim T, Krarup NHV, Grove EL, Rohde CV, Løfgren B. Initial assess-ment and treatment with the Airway, Breathing, Circulation, Disability, Exposure (ABCDE) approach. International Journal of General Medicine. 2012; 5: 117–121.

[48] Imsuwan I. Vasopressor in the emergency room. Thammasat Medical Journal. 2015; 15: 10.

[49] Olgers TJ, Dijkstra RS, Drost-de Klerck AM, Ter Maaten JC. The ABCDE primary assessment in the emergency department in medically ill patients: an observational pilot study. The Netherlands Journal of Medicine. 2017; 75: 106–111.

[50] Traub SJ, Wijdicks EF. Initial Diagnosis and Management of Coma. Emergency Medicine Clinics of North America. 2016; 34: 777–793.

[51] Wijdicks EFM. Management of the comatose patient. Handbook of Clinical Neurology. 2017; 140: 117–129.

[52] Seder DB, Bösel J. Airway management and mechanical ventilation in acute brain injury. Handbook of Clinical Neurology. 2017; 140: 15–32.

[53] Diango D, Moghomaye M, Maiga Y, Beye SA, Dembele AS, Coulibaly Y, et al. Coma in the elderly: Etiological factors, management, and prognosis in the department of anesthesia and intensive care. Anesthesia, Essays and Researches. 2011; 5: 153–157.

[54] Goswami A, Spencer R. Cardiovascular system: critical incidents. Anaesthesia & Intensive Care Medicine. 2017; 18: 219–223.

[55] Keller U. Nutritional Laboratory Markers in Malnutrition. Journal of Clinical Medicine. 2019; 8: 775

[56] McDougall M. Nutritional support in the critically ill. Anaesthesia & Intensive Care Medicine. 2015; 16: 171–173.

[57] Bruno M, Laureys S, Demertzi A. Coma and disorders of consciousness. Handbook of Clinical Neurology. 2013; 118: 205–213.

[58] Han JH, Wilber ST. Altered mental status in older patients in the emergency department. Clinics in Geriatric Medicine. 2013; 29: 101–136.

[59] Kottner J, Dassen T. Pressure ulcer risk assessment in critical care: interrater reliability and validity studies of the Braden and Waterlow scales and subjective ratings in two intensive care units. International Journal of Nursing Studies. 2010; 47: 671–677.

[60] Hoshijima H, Kuratani N, Takeuchi R, Shiga T, Masaki E, Doi K, et al. Effects of oral hygiene using chlorhexidine on preventing ventilator-associated pneumonia in critical-care settings: a meta-analysis of randomized controlled trials. Journal of Dental Sciences. 2013; 8: 348–357.

[61] Wijdicks EFM, Hijdra A, Young GB, Bassetti CL, Wiebe S. Practice Parameter: Prediction of outcome in comatose survivors after cardiopul-monary resuscitation (an evidence-based review). Neurology. 2006; 67: 203–210.

[62] Muengtaweepongsa S. Methods and clinical applications of targeted temperature management. Neurology Asia. 2015; 20: 325–333.

[63] De Georgia M, Raad B. Prognosis of coma after cardiac arrest in the era of hypothermia. Continuum. 2012; 18: 515–531.

[64] Panchal AR, Bartos JA, Cabañas JG, Donnino MW, Drennan IR, Hirsch KG, et al. Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2020; 142: S366–S468.

[65] Seewald S, Wnent J, Lefering R, Fischer M, Bohn A, Jantzen T, et al. CaRdiac Arrest Survival Score (CRASS) — a tool to predict good neurological outcome after out-of-hospital cardiac arrest. Resuscitation. 2020; 146: 66–73.

[66] Estraneo A, Moretta P, Loreto V, Santoro L, Trojano L. Clinical and neuropsychological long-term outcomes after late recovery of responsiveness: a case series. Archives of Physical Medicine and Rehabilitation. 2014; 95: 711–716.

[67] Kustermann T, Ata Nguepnjo Nguissi N, Pfeiffer C, Haenggi M, Kurmann R, Zubler F, et al. Brain functional connectivity during the first day of coma reflects long-term outcome. NeuroImage: Clinical. 2020; 27: 102295.

[68] Carrasco-Gómez M, Keijzer HM, Ruijter BJ, Bruña R, Tjepkema-Cloostermans MC, Hofmeijer J, et al. EEG functional connectivity contributes to outcome prediction of postanoxic coma. Clinical Neuro-physiology. 2021; 132: 1312–1320.

[69] Laureys S, Celesia GG, Cohadon F, Lavrijsen J, León-Carrión J, Sannita WG, et al. Unresponsive wakefulness syndrome: a new name for the vegetative state or apallic syndrome. BMC Medicine. 2010; 8: 68.

[70] Giacino JT, Ashwal S, Childs N, Cranford R, Jennett B, Katz DI, et al. The minimally conscious state: definition and diagnostic criteria. Neurology. 2002; 58: 349–353.

[71] Bruno M, Vanhaudenhuyse A, Thibaut A, Moonen G, Laureys S. From unresponsive wakefulness to minimally conscious PLUS and functional locked-in syndromes: recent advances in our understanding of disorders of consciousness. Journal of Neurology. 2011; 258: 1373–1384.

[72] Bruno M, Majerus S, Boly M, Vanhaudenhuyse A, Schnakers C, Gosseries O, et al. Functional neuroanatomy underlying the clinical subcategorization of minimally conscious state patients. Journal of Neurology. 2012; 259: 1087–1098.

[73] Poulsen I, Balle M, Givard KL. Nociception Coma Scale–Revised: Nurses’ Experience in Clinical Practice. Pain Management Nursing. 2019; 20: 592–598.

[74] Weaver JA, Liu J, Guernon A, Pape TB, Mallinson T. Psychometric Properties of the Coma near-Coma Scale for Adults in Disordered States of Consciousness: a Rasch Analysis. Archives of Physical Medicine and Rehabilitation. 2021; 102: 591–597.

[75] Giacino JT, Whyte J, Bagiella E, Kalmar K, Childs N, Khademi A, et al. Placebo-controlled trial of amantadine for severe traumatic brain injury. The New England Journal of Medicine. 2012; 366: 819–826.

[76] Giacino JT, Katz DI, Schiff ND, Whyte J, Ashman EJ, Ashwal S, et al. Practice Guideline Update Recommendations Summary: Disorders of Consciousness: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology; the American Congress of Rehabilitation Medicine; and the National Institute on Disability, Independent Living, and Rehabilitation Research. Archives of Physical Medicine and Rehabilitation. 2018; 99: 1699–1709.

[77] Thibaut A, Schiff N, Giacino J, Laureys S, Gosseries O. Therapeutic interventions in patients with prolonged disorders of consciousness. The Lancet Neurology. 2019; 18: 600–614.

Abstracted / indexed in

Science Citation Index Expanded (SciSearch) Created as SCI in 1964, Science Citation Index Expanded now indexes over 9,200 of the world’s most impactful journals across 178 scientific disciplines. More than 53 million records and 1.18 billion cited references date back from 1900 to present.

Journal Citation Reports/Science Edition Journal Citation Reports/Science Edition aims to evaluate a journal’s value from multiple perspectives including the journal impact factor, descriptive data about a journal’s open access content as well as contributing authors, and provide readers a transparent and publisher-neutral data & statistics information about the journal.

Chemical Abstracts Service Source Index The CAS Source Index (CASSI) Search Tool is an online resource that can quickly identify or confirm journal titles and abbreviations for publications indexed by CAS since 1907, including serial and non-serial scientific and technical publications.

IndexCopernicus The Index Copernicus International (ICI) Journals database’s is an international indexation database of scientific journals. It covered international scientific journals which divided into general information, contents of individual issues, detailed bibliography (references) sections for every publication, as well as full texts of publications in the form of attached files (optional). For now, there are more than 58,000 scientific journals registered at ICI.

Geneva Foundation for Medical Education and Research The Geneva Foundation for Medical Education and Research (GFMER) is a non-profit organization established in 2002 and it works in close collaboration with the World Health Organization (WHO). The overall objectives of the Foundation are to promote and develop health education and research programs.

Scopus: CiteScore 0.5(2019) Scopus is Elsevier's abstract and citation database launched in 2004. Scopus covers nearly 36,377 titles (22,794 active titles and 13,583 Inactive titles) from approximately 11,678 publishers, of which 34,346 are peer-reviewed journals in top-level subject fields: life sciences, social sciences, physical sciences and health sciences.

Embase Embase (often styled EMBASE for Excerpta Medica dataBASE), produced by Elsevier, is a biomedical and pharmacological database of published literature designed to support information managers and pharmacovigilance in complying with the regulatory requirements of a licensed drug.

Submission Turnaround Time