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Luks AM, Beidleman BA, Freer L, Grissom CK, Keyes LE, McIntosh SE, Rodway GW, Schoene RB, Zafren K, Hackett PH. Wilderness Medical Society Clinical Practice Guidelines for the Prevention, Diagnosis, and Treatment of Acute Altitude Illness: 2024 Update. Wilderness Environ Med 2024; 35:2S-19S. [PMID: 37833187 DOI: 10.1016/j.wem.2023.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 04/14/2023] [Accepted: 05/17/2023] [Indexed: 10/15/2023]
Abstract
To provide guidance to clinicians about best practices, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for prevention, diagnosis, and treatment of acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. Recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches for managing each form of acute altitude illness that incorporate these recommendations as well as recommendations on how to approach high altitude travel following COVID-19 infection. This is an updated version of the original WMS Consensus Guidelines for the Prevention and Treatment of Acute Altitude Illness published in Wilderness & Environmental Medicine in 2010 and the subsequently updated WMS Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness published in 2014 and 2019.
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Affiliation(s)
- Andrew M Luks
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, WA
| | - Beth A Beidleman
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, MA
| | - Luanne Freer
- Everest ER, Himalayan Rescue Association, Kathmandu, Nepal
| | - Colin K Grissom
- Pulmonary and Critical Care Medicine, Intermountain Healthcare and the University of Utah, Salt Lake City, UT
| | - Linda E Keyes
- Department of Emergency Medicine, Section of Wilderness Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO
| | - Scott E McIntosh
- Department of Emergency Medicine, University of Utah Health, Salt Lake City, UT
| | - George W Rodway
- Department of Family Medicine-Sports Medicine, University of Nevada, Reno School of Medicine, Reno, NV
| | - Robert B Schoene
- Division of Pulmonary and Critical Care Medicine, Sound Physicians, St. Mary's Medical Center and Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco, CA
| | - Ken Zafren
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA
- Himalayan Rescue Association, Kathmandu, Nepal
| | - Peter H Hackett
- Altitude Research Center, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
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Retinal microvasculature is a potential biomarker for acute mountain sickness. SCIENCE CHINA. LIFE SCIENCES 2023:10.1007/s11427-022-2271-x. [PMID: 36811802 DOI: 10.1007/s11427-022-2271-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 12/21/2022] [Indexed: 02/24/2023]
Abstract
Increased cerebral blood flow resulting from altered capillary level autoregulation at high altitudes leads to capillary overperfusion and then vasogenic cerebral edema, which is the leading hypothesis of acute mountain sickness (AMS). However, studies on cerebral blood flow in AMS have been mostly restricted to gross cerebrovascular endpoints as opposed to the microvasculature. This study aimed to investigate ocular microcirculation alterations, the only visualized capillaries in the central neural system (CNS), during early-stage AMS using a hypobaric chamber. This study found that after high altitude simulation, the optic nerve showed retinal nerve fiber layer thickening (P=0.004-0.018) in some locations, and the area of the optic nerve subarachnoid space (P=0.004) enlarged. Optical coherence tomography angiography (OCTA) showed increased retinal radial peripapillary capillary (RPC) flow density (P=0.003-0.046), particularly on the nasal side of the nerve. The AMS-positive group had the largest increases in RPC flow density in the nasal sector (AMS-positive, Δ3.21±2.37; AMS-negative, Δ0.01±2.16, P=0.004). Among multiple ocular changes, OCTA increase in RPC flow density was associated with simulated early-stage AMS symptoms (beta=0.222, 95%CI, 0.009-0.435, P=0.042). The area under the receiver operating characteristics curve (AUC) for the changes in RPC flow density to predict early-stage AMS outcomes was 0.882 (95%CI, 0.746-0.998). The results further confirmed that overperfusion of microvascular beds is the key pathophysiologic change in early-stage AMS. RPC OCTA endpoints may serve as a rapid, noninvasive potential biomarker for CNS microvascular changes and AMS development during risk assessment of individuals at high altitudes.
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Lau T, Ahn JS, Manji R, Kim DJ. A Narrative Review of Point of Care Ultrasound Assessment of the Optic Nerve in Emergency Medicine. Life (Basel) 2023; 13:life13020531. [PMID: 36836888 PMCID: PMC9962087 DOI: 10.3390/life13020531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/05/2023] [Accepted: 02/14/2023] [Indexed: 02/17/2023] Open
Abstract
Point of care ultrasound (POCUS) of the optic nerve is easy to learn and has great diagnostic potential. Within emergency medicine, research has primarily focused on its use for the assessment of increased intracranial pressure, but many other applications exist, though the literature is heterogeneous and largely observational. This narrative review describes the principles of POCUS of the optic nerve including anatomy and scanning technique, as well as a summary of its best studied clinical applications of relevance in emergency medicine: increased intracranial pressure, idiopathic intracranial hypertension, optic neuritis, acute mountain sickness, and pediatric intracranial pressure assessment. In many of these applications, sonographic optic nerve sheath diameter (ONSD) has moderately high sensitivity and specificity, but the supporting studies are heterogeneous. Further studies should focus on standardization of the measurement of ONSD, establishment of consistent diagnostic thresholds for elevated intracranial pressure, and automation of ONSD measurement.
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Affiliation(s)
- Torey Lau
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Department of Emergency Medicine, St. Paul’s Hospital, Vancouver, BC V6Z 1Y6, Canada
| | - Justin S. Ahn
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Department of Emergency Medicine, Royal Columbian Hospital, New Westminster, BC V3L 3W7, Canada
| | - Rahim Manji
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Department of Emergency Medicine, St. Paul’s Hospital, Vancouver, BC V6Z 1Y6, Canada
| | - Daniel J. Kim
- Department of Emergency Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Department of Emergency Medicine, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada
- Correspondence: ; Tel.: +1-604-875-4855
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Vitiello L, De Bernardo M, Capasso L, Cornetta P, Rosa N. Optic Nerve Ultrasound Evaluation in Animals and Normal Subjects. Front Med (Lausanne) 2022; 8:797018. [PMID: 35071277 PMCID: PMC8766506 DOI: 10.3389/fmed.2021.797018] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022] Open
Abstract
In recent years, ultrasonographic measurement of the optic nerve sheath diameter (ONSD) has been widely used to identify the presence of increased intracranial pressure (ICP). Intracranial hypertension is a life-threatening condition that can be caused by various neurological and non-neurological disorders, and it is associated to poor clinical results. Ultrasonography could be used to qualitatively and efficiently detect ICP increases, but to reach this purpose, clear cut-off values are mandatory. The aim of this review is to provide a wide overview of the most important scientific publications on optic nerve ultrasound normal values assessment published in the last 30 years. A total of 42 articles selected from PubMed medical database was included in this review. Our analysis showed that ocular ultrasonography is considered to be a valuable diagnostic tool, especially when intracranial hypertension is suspected, but unfortunately this research provided conflicting results that could be due to the different ultrasound protocols. This is mainly caused by the use of B scan alone, which presents several limitations. The use of B-scan coupled with the standardized A-scan approach could give more accurate, and reliable ultrasound evaluation, assuring higher data objectivity.
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Affiliation(s)
- Livio Vitiello
- Eye Unit, Department of Medicine, Surgery and Dentistry, "Scuola Medica Salernitana", University of Salerno, Baronissi, Italy
| | - Maddalena De Bernardo
- Eye Unit, Department of Medicine, Surgery and Dentistry, "Scuola Medica Salernitana", University of Salerno, Baronissi, Italy
| | - Luigi Capasso
- Corneal Transplant Unit, Azienda Sanitaria Locale (ASL) Napoli 1, Naples, Italy
| | - Palmiro Cornetta
- Eye Unit, "Maria SS Addolorata" Hospital, Azienda Sanitaria Locale (ASL) Salerno, Eboli, Italy
| | - Nicola Rosa
- Eye Unit, Department of Medicine, Surgery and Dentistry, "Scuola Medica Salernitana", University of Salerno, Baronissi, Italy
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Wipplinger F, Holthof N, Lienert J, Maeder MB, Moens D. In reply to Vitiello, De Bernardo, Capasso, and Rosa. Wilderness Environ Med 2021; 32:408-409. [PMID: 34303606 DOI: 10.1016/j.wem.2021.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 05/17/2021] [Indexed: 11/17/2022]
Affiliation(s)
- Flavia Wipplinger
- Department of Anesthesiology and Pain Medicine, Inselspital Bern University Hospital, Bern, Switzerland
| | - Niels Holthof
- Department of Anesthesiology and Pain Medicine, Inselspital Bern University Hospital, Bern, Switzerland
| | - Jasmin Lienert
- Department of Emergency Medicine, Hôpital du Valais, Sion, Switzerland
| | - Monika Brodmann Maeder
- Department of Emergency Medicine, Inselspital Bern University Hospital, Bern, Switzerland; Institute for Mountain Emergency Medicine, EURAC Research, Bolzano, Italy
| | - Didier Moens
- Department of Emergency Medicine, Liège University Hospital, Liège, Belgium
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Point-of-Care Ultrasound Diagnosis of Acute High Altitude Illness: A Case Report. Wilderness Environ Med 2021; 32:204-209. [DOI: 10.1016/j.wem.2020.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 02/04/2023]
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Tsai TY, Gozari G, Su YC, Lee YK, Tu YK. Optic nerve sheath diameter changes at high altitude and in acute mountain sickness: meta-regression analyses. Br J Ophthalmol 2020; 106:731-735. [PMID: 33310776 DOI: 10.1136/bjophthalmol-2020-317717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/09/2020] [Accepted: 11/17/2020] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS To assess changes in optic nerve sheath diameter (ONSD) at high altitude and in acute mountain sickness (AMS). METHODS Cochrane Library, EMBASE, Google Scholar and PubMed were searched for articles published from their inception to 31st of July 2020. Outcome measures were mean changes of ONSD at high altitude and difference in ONSD change between subjects with and without AMS. Meta-regressions were conducted to investigate the relation of ONSD change to altitude and time spent at that altitude. RESULTS Eight studies with 248 participants comparing ONSD from sea level to high altitude, and five studies with 454 participants comparing subjects with or without AMS, were included. ONSD increased by 0.14 mm per 1000 m after adjustment for time (95% CI: 0.10 to 0.18; p<0.01). Restricted cubic spline regression revealed an almost linear relation between ONSD change and time within 2 days. ONSD was greater in subjects with AMS (mean difference=0.47; 95% CI: 0.14 to 0.80; p=0.01; I2=89.4%). CONCLUSION Our analysis shows that ONSD changes correlate with altitude and tend to increase in subjects with AMS. Small study number and high heterogeneity are the limitations of our study. Further large prospective studies are required to verify our findings.
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Affiliation(s)
- Tou-Yuan Tsai
- Emergency Department, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan
| | - George Gozari
- Emergency Department, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan
| | - Yung-Cheng Su
- Emergency Department, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.,School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Yi-Kung Lee
- Emergency Department, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.,School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Yu-Kang Tu
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan .,Department of Dentistry, National Taiwan University Hospital and School of Dentistry, National Taiwan University, Taipei, Taiwan.,Research Center of Big Data and Meta-analysis, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
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Krusche T, Limmer M, Jendrusch G, Platen P. Influence of Natural Hypobaric Hypoxic Conditions on Dynamic Visual Performance. High Alt Med Biol 2020; 21:1-11. [PMID: 31746645 DOI: 10.1089/ham.2019.0033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Background: Both dynamic and static visual performances are essential for safety and motoric performance at altitude. There is a lack of information regarding alterations in dynamic visual performance (DVP) in oxygen-reduced environments. The purpose of this study was to analyze DVP in natural hypoxic conditions in a group of young, healthy hikers. Methods: DVP in four parafoveal subfields was analyzed using the computer-assisted Düsseldorf Test for Dynamic Vision. Measurements were performed twice at altitudes above 3500 m during an 8-day alpine hike. Results: On day 5 (3647 m), no changes in DVP were detected. On day 6 (4554 m), however, we found a significant reduction in DVP in the superior parafoveal retinal subfield, partly representing the lower visual field. The observed changes did not correlate with oxygen saturation, hematocrit, or cardiovascular parameters. We found no interrelation between symptoms of acute mountain sickness and DVP at altitude. Conclusions: Our data suggest that hiking at altitudes above 4500 m results in lower DVP in the visual field of healthy young people. The alteration might affect motor performance and coordination, increasing the risk of accidents.
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Affiliation(s)
- Till Krusche
- Department of Sports Medicine and Sports Nutrition, Faculty of Sport Science, Ruhr-Universität Bochum, Bochum, Germany
| | - Mirjam Limmer
- Department of Sports Medicine and Sports Nutrition, Faculty of Sport Science, Ruhr-Universität Bochum, Bochum, Germany.,Institute of Outdoor Sports and Environmental Science, German Sport University Cologne, Cologne, Germany
| | - Gernot Jendrusch
- Department of Sports Medicine and Sports Nutrition, Faculty of Sport Science, Ruhr-Universität Bochum, Bochum, Germany
| | - Petra Platen
- Department of Sports Medicine and Sports Nutrition, Faculty of Sport Science, Ruhr-Universität Bochum, Bochum, Germany
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Gül F, Sayan İ, Arıkan H, Karacabey S, Arslantaş MK, Cinel İ. The Role of Transocular Ultrasound in the Assessment of Neurotoxicity-Related Encephalopathy in Mushroom Poisoning. Turk J Anaesthesiol Reanim 2019; 48:62-67. [PMID: 32076682 PMCID: PMC7001805 DOI: 10.5152/tjar.2019.37891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 05/29/2019] [Indexed: 11/30/2022] Open
Abstract
Objective Mushroom poisonings can lead to life-threatening organ dysfunctions and neurotoxicity-related encephalopathy. This study aimed to detect increased intracranial pressure by measuring optic nerve sheath diameter (ONSD) ultrasonographically and to determine its association with clinical and laboratory parameters. Methods In this prospective case-control study, we evaluated the patients aged above 18 years who presented to the emergency department with mushroom poisoning. Vital signs, clinical and laboratory parameters and ONSD of both eyes measured with transocular ultrasound were noted at initial admission and the 24th hour. Results We measured ONSD in 26 cases with mushroom poisoning and 26 healthy volunteers. Baseline ONSD measurements of the poisoning group were significantly higher than those of the control group (5.94±0.73 vs. 4.11±0.64, p<0.0001). ONSD values significantly regressed at 24th hour compared with the baseline measurements in the poisoning group (5.94±0.73 vs. 5.06±0.56, p<0.001).The ONSD values were significantly higher in patients who had a clinical picture of encephalopathy compared with patients who didn’t have (6.05±0.72 vs. 4.36±1.03, p<0.001). No significant deterioration was observed in ammonium levels, hepatic and renal functions of the patients. Conclusion We detected increased ONSDs in patients with mushroom poisoning compared with those in the control healthy volunteers. Our findings suggest that ONSD, measured by ultrasonography, may be safely and effectively used to diagnose transient encephalopathy associated with neurotoxicity.
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Affiliation(s)
- Fethi Gül
- Department of Anaesthesiology and Reanimation, Marmara University Pendik Training and Reserach Hospital, İstanbul, Turkey
| | - İsmet Sayan
- Department of Pulmonary and Critical Care Medicine, Marmara University School of Medicine, İstanbul, Turkey
| | - Hüseyin Arıkan
- Department of Pulmonary and Critical Care Medicine, Marmara University School of Medicine, İstanbul, Turkey
| | - Sinan Karacabey
- Department of Traumatology and Emergency Medicine, Marmara University School of Medicine, İstanbul, Turkey
| | - Mustafa Kemal Arslantaş
- Department of Anaesthesiology and Reanimation, Marmara University School of Medicine, İstanbul, Turkey
| | - İsmail Cinel
- Department of Anesthesiology and Reanimation, Division of Critical Care Medicine, Marmara University School of Medicine, İstanbul, Turkey
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Weber U, Schiefer J, Mühlbacher J, Bernardi MH, Ortner CM, Jaksch P. High altitude trekking after lung transplantation: a prospective study using lung ultrasound to detect comets tails for interstitial pulmonary edema in lung transplant recipients and healthy volunteers. Transpl Int 2018; 31:1245-1253. [PMID: 29928768 DOI: 10.1111/tri.13307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/15/2018] [Indexed: 12/26/2022]
Abstract
The intensity of physical activity which can be tolerated after lung transplantation and the tolerance to prolonged exercise at high altitude are poorly investigated. Lung ultrasound comet tails have been used in the diagnosis of interstitial pulmonary edema and high pulmonary altitude edema. The aim was to assess the number of lung ultrasound comet tails and to monitor changes in the optic nerve sheath diameter (ONSD) during a climb to the top of Mount Kilimanjaro in 10 lung transplant recipients and 10 healthy controls at three different altitude levels: 1360, 3505, 4900 m. Lung transplant recipients showed a constant increase in comet tail scores with altitude, whereas control subjects only showed an increase at the highest measurement point. Differences between groups (transplant versus control) reached significance only after the first ascend: 0.9 (95% CI: -0.41; 2.21) vs. 0.1 (95% CI: -0.12; 0.32) (P = 0.2; 1360 m), 2.33 (95% CI: 0.64; 4.02) vs. 0.3 (95% CI: -0.18; 0.78) (P = 0.04; 3505 m), and 4.11 (95% CI: 0.13; 0.34) vs. 2.9 (95% CI: 0.49; 5.31) (P = 0.15; 4900 m); ONSD increased significantly in both groups from 3.53 (95% CI: 0.34; 0.66) at 1360 m to 4.11 (95% CI: 0.36; 0.71) at 4900 m (P < 0.05). Lungs of transplant recipients are able to adapt to altitude and capable of performing prolonged exercise at high altitude after slow ascend.
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Affiliation(s)
- Ulrike Weber
- Division of Cardiac Thoracic Vascular Anaesthesia and Intensive Care Medicine, Department of Anaesthesiology, General Intensive Care and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Judith Schiefer
- Division of Cardiac Thoracic Vascular Anaesthesia and Intensive Care Medicine, Department of Anaesthesiology, General Intensive Care and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Jakob Mühlbacher
- Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - Martin Hermann Bernardi
- Division of Cardiac Thoracic Vascular Anaesthesia and Intensive Care Medicine, Department of Anaesthesiology, General Intensive Care and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Clemens Maria Ortner
- Division of Cardiac Thoracic Vascular Anaesthesia and Intensive Care Medicine, Department of Anaesthesiology, General Intensive Care and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Peter Jaksch
- Department of Thoracic Surgery, Medical University of Vienna, Vienna, Austria
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Schatz A, Guggenberger V, Fischer MD, Schommer K, Bartz-Schmidt KU, Gekeler F, Willmann G. Optic nerve oedema at high altitude occurs independent of acute mountain sickness. Br J Ophthalmol 2018; 103:bjophthalmol-2018-312224. [PMID: 29973364 DOI: 10.1136/bjophthalmol-2018-312224] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 06/14/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND/AIMS The study aims to investigate changes in the optic nerve sheath diameter (ONSD) at high altitude and to assess correlation to optic disc oedema (ODE) and acute mountain sickness (AMS). This investigation is part of the Tübingen High Altitude Ophthalmology study. METHODS Fourteen volunteers ascended to 4559 m for 4 days before returning to low altitude. Ultrasonography of ONSD, quantification of optic disc parameters using a scanning laser ophthalmoscope and fluorescein angiography were performed at 341 m and at high altitude. Pearson's coefficient was used to correlate changes in ONSD with the optic disc and AMS. Assessment of AMS was performed using the Lake Louise (LL) and AMS-cerebral (AMS-C) scores of the Environmental Symptom Questionnaire-III. All volunteers were clinically monitored for heart rate (HR) and oxygen saturation (SpO2). RESULTS The mean ONSD at high altitude (4.6±0.3 mm, p<0.05) was significantly increased compared with baseline (3.8±0.4 mm) and remained enlarged throughout high-altitude exposure. This change in ONSD did not correlate with AMS (AMS-C, r=0.26, p=0.37; LL, r=0.21, p=0.48) and high-altitude headache (r=0.54, p=0.046), or clinical parameters of SpO2 (r=0.11, p=0.72) and HR (r=0.22, p=0.44). Increased ONSD did not correlate with altered key stereometric parameters of the optic disc describing ODE at high altitude (r<0.1, p>0.5). CONCLUSION High-altitude exposure leads to marked oedema formation of the optic nerve independent of AMS. Increased ONSD and ODE reflect hypoxia-driven oedema formation of the optic nerve at high altitude, providing important pathophysiological insight into high-altitude illness development and for future research.
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Affiliation(s)
- Andreas Schatz
- Department of Ophthalmology, University of Tübingen, Tübingen, Germany
- Department of Ophthalmology, Katharinenhospital, Stuttgart, Germany
| | | | - M Dominik Fischer
- Department of Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Kai Schommer
- Medizinischer Dienst der Krankenversicherungen, MDK Baden-Württemberg, Mannheim, Germany
| | | | - Florian Gekeler
- Department of Ophthalmology, University of Tübingen, Tübingen, Germany
- Department of Ophthalmology, Katharinenhospital, Stuttgart, Germany
| | - Gabriel Willmann
- Department of Ophthalmology, University of Tübingen, Tübingen, Germany
- Department of Ophthalmology, Katharinenhospital, Stuttgart, Germany
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Yanamandra U, Gupta A, Yanamandra S, Das SK, Patyal S, Nair V. Bedside Ultrasonography as an Alternative to Computed Tomography Scan for the Measurement of Optic Nerve Sheath Diameter. J Neurosci Rural Pract 2018; 9:252-255. [PMID: 29725178 PMCID: PMC5912033 DOI: 10.4103/jnrp.jnrp_537_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background Optic nerve sheath diameter (ONSD) as measured by optic nerve sheath ultrasonography (ONSU) is used as a surrogate marker of intracranial pressure (ICP), especially in resource-limited settings. There is a growing interest in the use of ONSU in emergency and high-altitude setups. Notwithstanding multiple studies done on this subject, there is a paucity of data regarding standardization of techniques and comparison of ONSU with computed tomography (CT). Materials and Methods Thirty-five patients with a diagnosis of high-altitude cerebral edema were enrolled in the study. ONSD was measured in all patients using ONSU, along visual and coronal axis, and CT scan. We repeated ONSU in these patients on days 3, 7, 10, and 15 (day of discharge). Correlation between visual and coronal axis as well as CT scan was analyzed. Results The correlation of visual to coronal and coronal to visual was equally significant (both correlation coefficients being R2 = 0.983). Correlation of ONSD by visual axis to CT scan was better than coronal axis (correlation coefficient R2 = 0.986 vs. 0.96, respectively). Conclusion In our study, we found a strong correlation between the visual and coronal axes. Thus, either of the two axes can be used for monitoring ICP. However, it has been found that measurements along the coronal axis are challenging, especially in the emergency setup. ONSD measured along visual axis correlated better with CT scan as compared to the coronal axis.
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Affiliation(s)
- Uday Yanamandra
- Department of Hematology, Army Hospital (Research & Referral), New Delhi, India
| | - Amul Gupta
- Department of Radiology, Military Hospital, Jaipur, Rajasthan, India
| | - Sushma Yanamandra
- Research Associate, Army Hospital (Research & Referral), New Delhi, India
| | - Subrat Kumar Das
- Research Associate, Army Hospital (Research & Referral), New Delhi, India
| | | | - Velu Nair
- Ex-Director General Medical Services (Army), New Delhi, India
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Noninvasive Brain Physiology Monitoring for Extreme Environments: A Critical Review. J Neurosurg Anesthesiol 2016; 27:318-28. [PMID: 25811362 DOI: 10.1097/ana.0000000000000175] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Our ability to monitor the brain physiology is advancing; however, most of the technology is bulky, expensive, and designed for traditional clinical settings. With long-duration space exploration, there is a need for developing medical technologies that are reliable, low energy, portable, and semiautonomous. Our aim was to review the state of the art for noninvasive technologies capable of monitoring brain physiology in diverse settings. A literature review of PubMed and the Texas Medical Center library sites was performed using prespecified search criteria to identify portable technologies for monitoring physiological aspects of the brain physiology. Most brain-monitoring technologies require a moderate to high degree of operator skill. Some are low energy, but many require a constant external power supply. Most of the technologies lack the accuracy seen in gold standard measures, due to the need for calibration, but may be useful for screening or monitoring relative changes in a parameter. Most of the technologies use ultrasound or electromagnetic radiation as energy sources. There is an important need for further development of portable technologies that can be operated in a variety of extreme environments to monitor brain health.
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Amini R, Stolz LA, Patanwala AE, Adhikari S. Coronal Axis Measurement of the Optic Nerve Sheath Diameter Using a Linear Transducer. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2015; 34:1607-1612. [PMID: 26254151 DOI: 10.7863/ultra.15.14.09039] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/07/2014] [Indexed: 06/04/2023]
Abstract
OBJECTIVES The true optic nerve sheath diameter cutoff value for detecting elevated intracranial pressure is variable. The variability may stem from the technique used to acquire sonographic measurements of the optic nerve sheath diameter as well as sonographic artifacts inherent to the technique. The purpose of this study was to compare the traditional visual axis technique to an infraorbital coronal axis technique for assessing the optic nerve sheath diameter using a high-frequency linear array transducer. METHODS We conducted a cross-sectional study at an academic medical center. Timed optic nerve sheath diameter measurements were obtained on both eyes of healthy adult volunteers with a 10-5-MHz broadband linear array transducer using both traditional visual axis and coronal axis techniques. Optic nerve sheath diameter measurements were obtained by 2 sonologists who graded the difficulty of each technique and were blinded to each other's measurements for each participant. RESULTS A total of 42 volunteers were enrolled, yielding 84 optic nerve sheath diameter measurements. There were no significant differences in the measurements between the techniques on either eye (P = .23 [right]; P = .99 [left]). Additionally, there was no difference in the degree of difficulty obtaining the measurements between the techniques (P = .16). There was a statistically significant difference in the time required to obtain the measurements between the traditional and coronal techniques (P < .05). CONCLUSIONS Infraorbital coronal axis measurements are similar to measurements obtained in the traditional visual axis. The infraorbital coronal axis technique is slightly faster to perform and is not technically challenging.
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Affiliation(s)
- Richard Amini
- Department of Emergency Medicine, University of Arizona Medical Center, Tucson, Arizona USA (R.A., L.A.S., S.A.); and Department of Pharmacy, College of Medicine, University of Arizona, Tucson, Arizona USA (A.E.P.).
| | - Lori A Stolz
- Department of Emergency Medicine, University of Arizona Medical Center, Tucson, Arizona USA (R.A., L.A.S., S.A.); and Department of Pharmacy, College of Medicine, University of Arizona, Tucson, Arizona USA (A.E.P.)
| | - Asad E Patanwala
- Department of Emergency Medicine, University of Arizona Medical Center, Tucson, Arizona USA (R.A., L.A.S., S.A.); and Department of Pharmacy, College of Medicine, University of Arizona, Tucson, Arizona USA (A.E.P.)
| | - Srikar Adhikari
- Department of Emergency Medicine, University of Arizona Medical Center, Tucson, Arizona USA (R.A., L.A.S., S.A.); and Department of Pharmacy, College of Medicine, University of Arizona, Tucson, Arizona USA (A.E.P.)
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Kanaan NC, Lipman GS, Constance BB, Holck PS, Preuss JF, Williams SR. Optic Nerve Sheath Diameter Increase on Ascent to High Altitude: Correlation With Acute Mountain Sickness. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2015; 34:1677-1682. [PMID: 26269295 DOI: 10.7863/ultra.15.14.10060] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
OBJECTIVES Elevated optic nerve sheath diameter on sonography is known to correlate with increased intracranial pressure and is observed in acute mountain sickness. This study aimed to determine whether optic nerve sheath diameter changes on ascent to high altitude are associated with acute mountain sickness incidence. METHODS Eighty-six healthy adults enrolled at 1240 m (4100 ft), drove to 3545 m (11,700 ft) and then hiked to and slept at 3810 m (12,500 ft). Lake Louise Questionnaire scores and optic nerve sheath diameter measurements were taken before, the evening of, and the morning after ascent. RESULTS The incidence of acute mountain sickness was 55.8%, with a mean Lake Louise Questionnaire score ± SD of 3.81 ± 2.5. The mean maximum optic nerve sheath diameter increased on ascent from 5.58 ± 0.79 to 6.13 ± 0.73 mm, a difference of 0.91 ± 0.55 mm (P = .09). Optic nerve sheath diameter increased at high altitude regardless of acute mountain sickness diagnosis; however, compared to baseline values, we observed a significant increase in diameter only in those with a diagnosis of acute mountain sickness (0.57 ± 0.77 versus 0.21 ± 0.76 mm; P = .04). This change from baseline, or Δ optic nerve sheath diameter, was associated with twice the odds of developing acute mountain sickness (95% confidence interval, 1.08-3.93). CONCLUSIONS The mean optic nerve sheath diameter increased on ascent to high altitude compared to baseline values, but not to a statistically significant degree. The magnitude of the observed Δ optic nerve sheath diameter was positively associated with acute mountain sickness diagnosis. No such significant association was found between acute mountain sickness and diameter elevation above standard cutoff values, limiting the utility of sonography as a diagnostic tool.
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Affiliation(s)
- Nicholas C Kanaan
- University of Utah, Salt Lake City, Utah USA (N.C.K.); Stanford University School of Medicine, Palo Alto, California USA (G.S.L., S.R.W.); Tacoma General Hospital, Tacoma, Washington USA (B.B.C.); University of Hawaii, Honolulu, Hawaii USA (P.S.H.); and Royal Perth Hospital, Perth, Western Australia, Australia (J.F.P.).
| | - Grant S Lipman
- University of Utah, Salt Lake City, Utah USA (N.C.K.); Stanford University School of Medicine, Palo Alto, California USA (G.S.L., S.R.W.); Tacoma General Hospital, Tacoma, Washington USA (B.B.C.); University of Hawaii, Honolulu, Hawaii USA (P.S.H.); and Royal Perth Hospital, Perth, Western Australia, Australia (J.F.P.)
| | - Benjamin B Constance
- University of Utah, Salt Lake City, Utah USA (N.C.K.); Stanford University School of Medicine, Palo Alto, California USA (G.S.L., S.R.W.); Tacoma General Hospital, Tacoma, Washington USA (B.B.C.); University of Hawaii, Honolulu, Hawaii USA (P.S.H.); and Royal Perth Hospital, Perth, Western Australia, Australia (J.F.P.)
| | - Peter S Holck
- University of Utah, Salt Lake City, Utah USA (N.C.K.); Stanford University School of Medicine, Palo Alto, California USA (G.S.L., S.R.W.); Tacoma General Hospital, Tacoma, Washington USA (B.B.C.); University of Hawaii, Honolulu, Hawaii USA (P.S.H.); and Royal Perth Hospital, Perth, Western Australia, Australia (J.F.P.)
| | - James F Preuss
- University of Utah, Salt Lake City, Utah USA (N.C.K.); Stanford University School of Medicine, Palo Alto, California USA (G.S.L., S.R.W.); Tacoma General Hospital, Tacoma, Washington USA (B.B.C.); University of Hawaii, Honolulu, Hawaii USA (P.S.H.); and Royal Perth Hospital, Perth, Western Australia, Australia (J.F.P.)
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Lochner P, Falla M, Brigo F, Pohl M, Strapazzon G. Ultrasonography of the Optic Nerve Sheath Diameter for Diagnosis and Monitoring of Acute Mountain Sickness: A Systematic Review. High Alt Med Biol 2015; 16:195-203. [DOI: 10.1089/ham.2014.1127] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Affiliation(s)
- Piergiorgio Lochner
- Department of Neurology, General Hospital of Merano, Merano, Italy
- Department of Neurology, University A. Avogadro, Novara, Italy
| | - Marika Falla
- Department of Neurology and Psychiatry, Sapienza University, Roma, Italy
- Department of Neurology, General Hospital of Bolzano, Bolzano, Italy
| | - Francesco Brigo
- Department of Neurology, General Hospital of Merano, Merano, Italy
- Department of Neurological and Movement Sciences, University of Verona, Italy
| | - Michael Pohl
- EURAC Institute of Mountain Emergency Medicine, Bolzano, Italy
- Landeskrankenhaus Bregenz, Austria
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Wilson MH, Imray CHE. The cerebral venous system and hypoxia. J Appl Physiol (1985) 2015; 120:244-50. [PMID: 26294747 DOI: 10.1152/japplphysiol.00327.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 08/13/2015] [Indexed: 01/24/2023] Open
Abstract
Most hypobaric hypoxia studies have focused on oxygen delivery and therefore cerebral blood inflow. Few have studied venous outflow. However, the volume of blood entering and leaving the skull (∼700 ml/min) is considerably greater than cerebrospinal fluid production (0.35 ml/min) or edema formation rates and slight imbalances of in- and outflow have considerable effects on intracranial pressure. This dynamic phenomenon is not necessarily appreciated in the currently taught static "Monro-Kellie" doctrine, which forms the basis of the "Tight-Fit" hypothesis thought to underlie high altitude headache, acute mountain sickness, and high altitude cerebral edema. Investigating both sides of the cerebral circulation was an integral part of the 2007 Xtreme Everest Expedition. The results of the relevant studies performed as part of and subsequent to this expedition are reviewed here. The evidence from recent studies suggests a relative venous outflow insufficiency is an early step in the pathogenesis of high altitude headache. Translation of knowledge gained from high altitude studies is important. Many patients in a critical care environment develop hypoxemia akin to that of high altitude exposure. An inability to drain the hypoxemic induced increase in cerebral blood flow could be an underappreciated regulatory mechanism of intracranial pressure.
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Affiliation(s)
- Mark H Wilson
- The Centre for Altitude, Space and Extreme Environment Medicine, University College London, London, United Kingdom; The Birmingham Medical Research Expeditionary Society, Queen Elizabeth Hospital, Edgbaston, Birmingham, United Kingdom; Imperial Neurotrauma Centre, Imperial College, St Mary's Hospital, London, United Kingdom; Institute of Pre-Hospital Care, London's Air Ambulance, Royal London Hospital, Whitechapel, United Kingdom; and
| | - Christopher H E Imray
- The Centre for Altitude, Space and Extreme Environment Medicine, University College London, London, United Kingdom; The Birmingham Medical Research Expeditionary Society, Queen Elizabeth Hospital, Edgbaston, Birmingham, United Kingdom; Department of Surgery, Warwick Medical School, UHCW NHS Trust, Warwick, United Kingdom
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Ko SB. Optic Nerve Sheath Diameter on Brain Magnetic Resonance Imaging: A Single Center Study. JOURNAL OF NEUROCRITICAL CARE 2015. [DOI: 10.18700/jnc.2015.8.1.16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Change in optic nerve sheath diameter as a radiological marker of outcome from endoscopic third ventriculostomy in children. Childs Nerv Syst 2015; 31:721-8. [PMID: 25735849 DOI: 10.1007/s00381-015-2655-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 02/12/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE The purpose of this study was to investigate the value of the change in optic nerve sheath diameter (ONSD) as a radiological marker of endoscopic third ventriculostomy (ETV) outcome in children. METHODS Magnetic resonance imaging (MRI) scans of patients on whom ETVs were performed between the periods of January 2009 and June 2013 were reviewed. ONSD measurements on pre- and post-operative images were performed by two blinded observers, and the relationship between the change in these measurements and outcome from ETV were investigated. These findings were then also compared to conventional imaging features associated with ETV outcome. RESULTS MRI scans of 24 patients were adequate to measure the ONSD pre- and post-operatively. In patients with successful ETV (n = 19), the mean change in ONSD was 0.73 mm and in patients with a failed ETV (n = 5), the mean change in ONSD was 0.18 mm (p = 0.0007). A change in ONSD of 7.5 % of the initial measurement demonstrated a sensitivity of 92.9 % and a sensitivity of 85.7 % for ETV outcome (area under the receiver operating characteristic curve (AUROC) = 0.96). CONCLUSION Change in ONSD is a useful radiological marker of ETV outcome and may be used in combination with conventional radiological parameters to aid decision-making in this difficult group of patients.
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Affiliation(s)
- Mark H. Wilson
- The Brain Injury Centre—St Mary's Hospital, Imperial College, London, United Kingdom
- Birmingham Medical Research Expeditionary Society, Birmingham, United Kingdom
- The Institute of Pre-Hospital Care, London's Air Ambulance, Barts and the London Medical School, Queen Mary University of London, The Helipad, The Royal London Hospital, Whitechapel, United Kingdom
| | - Alex Wright
- Birmingham Medical Research Expeditionary Society, Birmingham, United Kingdom
| | - Christopher H.E. Imray
- University Hospital Coventry and Warwickshire NHS Trust and Warwick Medical School, Coventry, United Kingdom
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Update on High Altitude Cerebral Edema Including Recent Work on the Eye. High Alt Med Biol 2014; 15:112-22. [DOI: 10.1089/ham.2013.1142] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Sightings edited by John W. Severinghaus. High Alt Med Biol 2013. [DOI: 10.1089/ham.2013.1423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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