Evaluation and Management of the Individual with Recurrent High Altitude Pulmonary Edema.

Luks AM, Grissom CK. Evaluation and Management of the Individual with Recurrent HAPE. High Alt Med Biol. 00:000-000, 2024. Individuals with a history of acute altitude illness often seek recommendations from medical providers on how to prevent such problems on future ascents to high elevation. Although many of these cases can be managed with pharmacologic prophylaxis and counseling about the appropriate rate of ascent alone, there are some situations in which further diagnostic evaluation may also be warranted. One such situation is the individual with recurrent episodes of high altitude pulmonary edema (HAPE), as one of several predisposing factors may be present that warrants additional interventions beyond pharmacologic prophylaxis and slow ascent and may even preclude future travel to high altitude. This review considers this situation in greater detail. Structured around the case of an otherwise healthy 27-year-old individual with recurrent episodes of HAPE who would like to climb Denali (6,190 m), the review examines the known risk factors for disease and then provides guidance regarding when and how to evaluate such individuals and appropriate steps to prevent HAPE on further ascents to high elevation. Except in rare circumstances, a history of recurrent HAPE does not preclude further ascent to high elevation, as a multipronged approach including pharmacologic prophylaxis, careful planning about the rate of ascent, and the degree of physical effort and other strategies, such as preacclimatization, staged ascent, and use of hypoxic tents, can be employed to reduce the risk of recurrence with future travel.

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Frostbite: 2024 Update.

The Wilderness Medical Society convened an expert panel to develop a set of evidence-based guidelines for the prevention and treatment of frostbite. We present a review of pertinent pathophysiology. We then discuss primary and secondary prevention measures and therapeutic management. Recommendations are made regarding each treatment and its role in management. These recommendations are graded on the basis of the quality of supporting evidence and balance between the benefits and risks or burdens for each modality according to methodology stipulated by the American College of Chest Physicians. This is an updated version of the guidelines published in 2019.

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2024 Update.

The Wilderness Medical Society (WMS) convened an expert panel in 2011 to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. The current panel retained 5 original members and welcomed 2 new members, all of whom collaborated remotely to provide an updated review of the classifications, pathophysiology, evidence-based guidelines for planning and preventive measures, and recommendations for field- and hospital-based therapeutic management of heat illness. These recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks or burdens for each modality. This is an updated version of the WMS clinical practice guidelines for the prevention and treatment of heat illness published in Wilderness & Environmental Medicine. 2019;30(4):S33-S46.

Wilderness Medical Society Clinical Practice Guidelines for Prevention and Management of Avalanche and Nonavalanche Snow Burial Accidents: 2024 Update.

To provide guidance to the general public, clinicians, and avalanche professionals about best practices, the Wilderness Medical Society convened an expert panel to revise the evidence-based guidelines for the prevention, rescue, and resuscitation of avalanche and nonavalanche snow burial victims. The original panel authored the Wilderness Medical Society Practice Guidelines for Prevention and Management of Avalanche and Nonavalanche Snow Burial Accidents in 2017. A second panel was convened to update these guidelines and make recommendations based on quality of supporting evidence.

Wilderness Medical Society Clinical Practice Guidelines for the Prevention, Diagnosis, and Treatment of Acute Altitude Illness: 2024 Update.

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.

Implementation of coordinated spontaneous awakening and breathing trials using telehealth-enabled, real-time audit and feedback for clinician adherence (TEACH): a type II hybrid effectiveness-implementation cluster-randomized trial.

BACKGROUND: Intensive care unit (ICU) patients on mechanical ventilation often require sedation and analgesia to improve comfort and decrease pain. Prolonged sedation and analgesia, however, may increase time on mechanical ventilation, risk for ventilator associated pneumonia, and delirium. Coordinated interruptions in sedation [spontaneous awakening trials (SATs)] and spontaneous breathing trials (SBTs) increase ventilator-free days and improve mortality. Coordination of SATs and SBTs is difficult with substantial implementation barriers due to difficult-to-execute sequencing between nurses and respiratory therapists. Telehealth-enabled remote care has the potential to overcome these barriers and improve coordinated SAT and SBT adherence by enabling proactive high-risk patient monitoring, surveillance, and real-time assistance to frontline ICU teams. METHODS: The telehealth-enabled, real-time audit and feedback for clinician adherence (TEACH) study will determine whether adding a telehealth augmented real-time audit and feedback to a usual supervisor-led audit and feedback intervention will yield higher coordinated SAT and SBT adherence and more ventilator-free days in mechanically ventilated patients than a usual supervisor-led audit and feedback intervention alone in a type II hybrid effectiveness-implementation cluster-randomized clinical trial in 12 Intermountain Health hospitals with 15 ICUs. In the active comparator control group (six hospitals), the only intervention is the usual supervisor-led audit and feedback implementation. The telehealth-enabled support (TEACH) intervention in six hospitals adds real-time identification of patients eligible for a coordinated SAT and SBT and consultative input from telehealth respiratory therapists, nurses, and physicians to the bedside clinicians to promote adherence including real-time assistance with execution. All intubated and mechanically ventilated patients ≥ 16 years of age are eligible for enrollment except for patients who die on the day of intubation or have preexisting brain death. Based on preliminary power analyses, we plan a 36-month intervention period that includes a 90-day run-in period. Estimated enrollment in the final analysis is up to 9900 mechanically ventilated patients over 33 months. DISCUSSION: The TEACH study will enhance implementation science by providing insight into how a telehealth intervention augmenting a usual audit and feedback implementation may improve adherence to coordinated SAT and SBT and increase ventilator-free days. TRIAL REGISTRATION: Clinicaltrials.gov, NCT05141396 , registered 12/02/2021.

Awakening and Breathing Coordination: A Mixed-Methods Analysis of Determinants of Implementation.

Rationale: Routine spontaneous awakening and breathing trial coordination (SAT/SBT) improves outcomes for mechanically ventilated patients, but adherence varies. Understanding barriers to and facilitators of consistent daily use of SAT/SBT (implementation determinants) can guide the development of implementation strategies to increase adherence to these evidence-based interventions. Objectives: We conducted an explanatory, sequential mixed-methods study to measure variation in the routine daily use of SAT/SBT and to identify implementation determinants that might explain variation in SAT/SBT use across 15 intensive care units (ICUs) in urban and rural locations within an integrated, community-based health system. Methods: We described the patient population and measured adherence to daily use of coordinated SAT/SBT from January to June 2021, selecting four sites with varied adherence levels for semistructured field interviews. We conducted key informant interviews with critical care nurses, respiratory therapists, and physicians/advanced practice clinicians (n = 55) from these four sites between October and December 2021 and performed content analysis to identify implementation determinants of SAT/SBT use. Results: The 15 sites had 1,901 ICU admissions receiving invasive mechanical ventilation (IMV) for ⩾24 hours during the measurement period. The mean IMV patient age was 58 years, and the median IMV duration was 5.3 days (interquartile range, 2.5-11.9). Coordinated SAT/SBT adherence (within 2 h) was estimated at 21% systemwide (site range, 9-68%). ICU clinicians were generally familiar with SAT/SBT but varied in their knowledge and beliefs about what constituted an evidence-based SAT/SBT. Clinicians reported that SAT/SBT coordination was difficult in the context of existing ICU workflows, and existing protocols did not explicitly define how coordination should be performed. The lack of an agreed-upon system-level measure for tracking daily use of SAT/SBT led to uncertainty regarding what constituted adherence. The effects of the COVID-19 pandemic increased clinician workloads, impacting performance. Conclusions: Coordinated SAT/SBT adherence varied substantially across 15 ICUs within an integrated, community-based health system. Implementation strategies that address barriers identified by this study, including knowledge deficits, challenges regarding workflow coordination, and the lack of performance measurement, should be tested in future hybrid implementation-effectiveness trials to increase adherence to daily use of coordinated SAT/SBT and minimize harm related to the prolonged use of mechanical ventilation and sedation.

Implementation of Lung-Protective Ventilation in Patients With Acute Respiratory Failure.

OBJECTIVES: We implemented a computerized protocol for low tidal volume ventilation (LTVV) to improve management and outcomes of mechanically ventilated patients with, and without, the acute respiratory distress syndrome (ARDS). DESIGN: Pragmatic, nonrandomized stepped wedge type II hybrid implementation/effectiveness trial. SETTING: Twelve hospitals in an integrated healthcare system over a 2-year period. PATIENTS: Patients greater than or equal to 18 years old who had initiation of mechanical ventilation in the emergency department or ICU. We excluded patients who died or transitioned to comfort care on the day of admission to the ICU. We defined a subgroup of patients with ARDS for analysis. INTERVENTIONS: Implementation of ventilator protocols for LTVV in the ICU. MEASUREMENTS AND MAIN RESULTS: Our primary clinical outcome was ventilator-free days (VFDs) to day 28. Our primary process outcome was median initial set tidal volume. We included 8,692 mechanically ventilated patients, 3,282 (38%) of whom had ARDS. After implementation, set tidal volume reported as mL/kg predicted body weight decreased from median 6.1 mL/kg (interquartile range [IQR], 6.0-6.8 mL/kg) to 6.0 mL/kg (IQR, 6.0-6.6 mL/kg) ( p = 0.009). The percent of patients receiving LTVV (tidal volume ≤ 6.5 mL/kg) increased from 69.8% ( n = 1,721) to 72.5% ( n = 1,846) ( p = 0.036) after implementation. The percent of patients receiving greater than 8 mL/kg initial set tidal volume was reduced from 9.0% ( n = 222) to 6.7% ( n = 174) ( p = 0.005) after implementation. Among patients with ARDS, day 1 positive end-expiratory pressure increased from 6.7 to 8.0 cm H 2 O ( p < 0.001). We observed no difference in VFD (adjusted odds ratio, 1.06; 95% CI, 0.91-1.24; p = 0.44), or in secondary outcomes of length of stay or mortality, either within the main cohort or the subgroup of patients with ARDS. CONCLUSIONS: We observed improved adherence to optimal ventilator management with implementation of a computerized protocol and reduction in the number of patients receiving tidal volumes greater than 8 mL/kg. We did not observe improvement in clinical outcomes.

Early Restrictive or Liberal Fluid Management for Sepsis-Induced Hypotension.

BACKGROUND: Intravenous fluids and vasopressor agents are commonly used in early resuscitation of patients with sepsis, but comparative data for prioritizing their delivery are limited. METHODS: In an unblinded superiority trial conducted at 60 U.S. centers, we randomly assigned patients to either a restrictive fluid strategy (prioritizing vasopressors and lower intravenous fluid volumes) or a liberal fluid strategy (prioritizing higher volumes of intravenous fluids before vasopressor use) for a 24-hour period. Randomization occurred within 4 hours after a patient met the criteria for sepsis-induced hypotension refractory to initial treatment with 1 to 3 liters of intravenous fluid. We hypothesized that all-cause mortality before discharge home by day 90 (primary outcome) would be lower with a restrictive fluid strategy than with a liberal fluid strategy. Safety was also assessed. RESULTS: A total of 1563 patients were enrolled, with 782 assigned to the restrictive fluid group and 781 to the liberal fluid group. Resuscitation therapies that were administered during the 24-hour protocol period differed between the two groups; less intravenous fluid was administered in the restrictive fluid group than in the liberal fluid group (difference of medians, -2134 ml; 95% confidence interval [CI], -2318 to -1949), whereas the restrictive fluid group had earlier, more prevalent, and longer duration of vasopressor use. Death from any cause before discharge home by day 90 occurred in 109 patients (14.0%) in the restrictive fluid group and in 116 patients (14.9%) in the liberal fluid group (estimated difference, -0.9 percentage points; 95% CI, -4.4 to 2.6; P = 0.61); 5 patients in the restrictive fluid group and 4 patients in the liberal fluid group had their data censored (lost to follow-up). The number of reported serious adverse events was similar in the two groups. CONCLUSIONS: Among patients with sepsis-induced hypotension, the restrictive fluid strategy that was used in this trial did not result in significantly lower (or higher) mortality before discharge home by day 90 than the liberal fluid strategy. (Funded by the National Heart, Lung, and Blood Institute; CLOVERS ClinicalTrials.gov number, NCT03434028.).

Delivery of Lung-protective Ventilation for Acute Respiratory Distress Syndrome: A Hybrid Implementation-Effectiveness Trial.

Rationale: Lung-protective ventilation (LPV) improves outcomes for patients with acute respiratory distress syndrome (ARDS), but adherence remains inadequate. Objectives: To measure the process and clinical impacts of implementation of a science-based intervention to improve LPV adherence for patients with ARDS, in part by increased use of clinical decision support (CDS). Methods: We conducted a type III hybrid implementation/effectiveness pilot trial enrolling adult patients with ARDS admitted to three hospitals before and after the launch of a multimodal implementation intervention to increase the use of mechanical ventilation CDS and improve LPV adherence. The primary outcome was patients' percentage of time adherent to low tidal volume (⩽6.5 ml/kg predicted body weight) ventilation (LTVV). Secondary outcomes included adherence to prescribed oxygenation settings, the use of the CDS tool's independent oxygenation and ventilation components, ventilator-free days, and mortality. Analyses employed multivariable regression to compare adjusted pre- versus postintervention outcomes after the exclusion of a postintervention wash-in period. A sensitivity analysis measured process outcomes' level and trend change postintervention using segmented regression. Results: The 446 included patients had a mean age of 60 years, and 43% were female. Demographic and clinical characteristics were similar pre- versus postintervention. The adjusted proportion of adherent time increased postintervention for LTVV (9.2%; 95% confidence interval [CI], 3.8-14.5%) and prescribed oxygenation settings (11.9%; 95% CI, 7.2-16.5%), as did the probability patients spent ⩾90% of ventilated time on LTVV (adjusted odds ratio [aOR] 2.58; 95% CI, 1.64-4.10) and use of ventilation CDS (aOR, 41.3%; 95% CI, 35.9-46.7%) and oxygenation CDS (aOR, 54.3%; 95% CI, 50.9-57.7%). Ventilator-free days (aOR, 1.15; 95% CI, 0.81-1.62) and 28-day mortality (aOR, 0.78; 95% CI, 0.50-1.20) did not change significantly after intervention. Segmented regression analysis supported a causal relationship between the intervention and improved CDS usage but suggested trends before intervention rather than the studied intervention could explain increased LPV adherence after the intervention. Conclusions: In this pilot trial, a multimodal implementation intervention was associated with increased use of ventilator management CDS for patients with ARDS but was not associated with differences in clinical outcomes and may not have independently caused the observed postintervention improvements in LPV adherence. Clinical trial registered with www.clinicaltrials.gov (NCT03984175).

IFITM3 regulates fibrinogen endocytosis and platelet reactivity in nonviral sepsis.

Platelets and megakaryocytes are critical players in immune responses. Recent reports suggest infection and inflammation alter the megakaryocyte and platelet transcriptome to induce altered platelet reactivity. We determined whether nonviral sepsis induces differential platelet gene expression and reactivity. Nonviral sepsis upregulated IFN-induced transmembrane protein 3 (IFITM3), an IFN-responsive gene that restricts viral replication. As IFITM3 has been linked to clathrin-mediated endocytosis, we determined whether IFITM3 promoted endocytosis of α-granule proteins. IFN stimulation enhanced fibrinogen endocytosis in megakaryocytes and platelets from Ifitm+/+ mice, but not Ifitm-/- mice. IFITM3 overexpression or deletion in megakaryocytes demonstrated IFITM3 was necessary and sufficient to regulate fibrinogen endocytosis. Mechanistically, IFITM3 interacted with clathrin and αIIb and altered their plasma membrane localization into lipid rafts. In vivo IFN administration increased fibrinogen endocytosis, platelet reactivity, and thrombosis in an IFITM-dependent manner. In contrast, Ifitm-/- mice were completely rescued from IFN-induced platelet hyperreactivity and thrombosis. During murine sepsis, platelets from Ifitm+/+ mice demonstrated increased fibrinogen content and platelet reactivity, which was dependent on IFN-α and IFITMs. Platelets from patients with nonviral sepsis had increases in platelet IFITM3 expression, fibrinogen content, and hyperreactivity. These data identify IFITM3 as a regulator of platelet endocytosis, hyperreactivity, and thrombosis during inflammatory stress.

Computer clinical decision support that automates personalized clinical care: a challenging but needed healthcare delivery strategy.

How to deliver best care in various clinical settings remains a vexing problem. All pertinent healthcare-related questions have not, cannot, and will not be addressable with costly time- and resource-consuming controlled clinical trials. At present, evidence-based guidelines can address only a small fraction of the types of care that clinicians deliver. Furthermore, underserved areas rarely can access state-of-the-art evidence-based guidelines in real-time, and often lack the wherewithal to implement advanced guidelines. Care providers in such settings frequently do not have sufficient training to undertake advanced guideline implementation. Nevertheless, in advanced modern healthcare delivery environments, use of eActions (validated clinical decision support systems) could help overcome the cognitive limitations of overburdened clinicians. Widespread use of eActions will require surmounting current healthcare technical and cultural barriers and installing clinical evidence/data curation systems. The authors expect that increased numbers of evidence-based guidelines will result from future comparative effectiveness clinical research carried out during routine healthcare delivery within learning healthcare systems.

An alert tool to promote lung protective ventilation for possible acute respiratory distress syndrome.

Objective: Computer-aided decision tools may speed recognition of acute respiratory distress syndrome (ARDS) and promote consistent, timely treatment using lung-protective ventilation (LPV). This study evaluated implementation and service (process) outcomes with deployment and use of a clinical decision support (CDS) synchronous alert tool associated with existing computerized ventilator protocols and targeted patients with possible ARDS not receiving LPV. Materials and Methods: We performed an explanatory mixed methods study from December 2019 to November 2020 to evaluate CDS alert implementation outcomes across 13 intensive care units (ICU) in an integrated healthcare system with >4000 mechanically ventilated patients annually. We utilized quantitative methods to measure service outcomes including CDS alert tool utilization, accuracy, and implementation effectiveness. Attitudes regarding the appropriateness and acceptability of the CDS tool were assessed via an electronic field survey of physicians and advanced practice providers. Results: Thirty-eight percent of study encounters had at least one episode of LPV nonadherence. Addition of LPV treatment detection logic prevented an estimated 1812 alert messages (41%) over use of disease detection logic alone. Forty-eight percent of alert recommendations were implemented within 2 h. Alert accuracy was estimated at 63% when compared to gold standard ARDS adjudication, with sensitivity of 85% and positive predictive value of 62%. Fifty-seven percent of survey respondents observed one or more benefits associated with the alert. Conclusion: Introduction of a CDS alert tool based upon ARDS risk factors and integrated with computerized ventilator protocol instructions increased visibility to gaps in LPV use and promoted increased adherence to LPV.

Association of the Intermountain Risk Score with major adverse health events in patients positive for COVID-19: an observational evaluation of a US cohort.

OBJECTIVES: The Intermountain Risk Score (IMRS), composed using published sex-specific weightings of parameters in the complete blood count (CBC) and basic metabolic profile (BMP), is a validated predictor of mortality. We hypothesised that IMRS calculated from prepandemic CBC and BMP predicts COVID-19 outcomes and that IMRS using laboratory results tested at COVID-19 diagnosis is also predictive. DESIGN: Prospective observational cohort study. SETTING: Primary, secondary, urgent and emergent care, and drive-through testing locations across Utah and in sections of adjacent US states. Viral RNA testing for SARS-CoV-2 was conducted from 3 March to 2 November 2020. PARTICIPANTS: Patients aged ≥18 years were evaluated if they had CBC and BMP measured in 2019 and tested positive for COVID-19 in 2020. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was a composite of hospitalisation or mortality, with secondary outcomes being hospitalisation and mortality separately. RESULTS: Among 3883 patients, 8.2% were hospitalised and 1.6% died. Subjects with low, mild, moderate and high-risk IMRS had the composite endpoint in 3.5% (52/1502), 8.6% (108/1256), 15.5% (152/979) and 28.1% (41/146) of patients, respectively. Compared with low-risk, subjects in mild-risk, moderate-risk and high-risk groups had HR=2.33 (95% CI 1.67 to 3.24), HR=4.01 (95% CI 2.93 to 5.50) and HR=8.34 (95% CI 5.54 to 12.57), respectively. Subjects aged <60 years had HR=3.06 (95% CI 2.01 to 4.65) and HR=7.38 (95% CI 3.14 to 17.34) for moderate and high risks versus low risk, respectively; those ≥60 years had HR=1.95 (95% CI 0.99 to 3.86) and HR=3.40 (95% CI 1.63 to 7.07). In multivariable analyses, IMRS was independently predictive and was shown to capture substantial risk variation of comorbidities. CONCLUSIONS: IMRS, a simple risk score using very basic laboratory results, predicted COVID-19 hospitalisation and mortality. This included important abilities to identify risk in younger adults with few diagnosed comorbidities and to predict risk prior to SARS-CoV-2 infection.

Initial Derivation of a Predictive Model for Left Ventricular Longitudinal Strain (LS) in Early Sepsis.

Septic shock is a common deadly disease often associated with cardiovascular dysfunction. Left ventricular longitudinal strain (LV LS) has been proposed as a sensitive marker to measure cardiovascular function; however, it is not available universally in standard clinical echocardiograms. We sought to derive a predictive model for LV LS, using machine learning techniques with the hope that we may uncover surrogates for LV LS. We found that left ventricular ejection fraction, tricuspid annular plane systolic excursion, sepsis source, height, mitral valve Tei index, LV systolic dimension, aortic valve ejection time, and peak acceleration rate were all predictive of LV LS in this initial exploratory model. Future modeling work may uncover combinations of these variables which may be powerful surrogates for LV LS and cardiovascular function.

Positive End-Expiratory Pressure and Respiratory Rate Modify the Association of Mechanical Power and Driving Pressure With Mortality Among Patients With Acute Respiratory Distress Syndrome.

IMPORTANCE: Mechanical power and driving pressure have known associations with survival for patients with acute respiratory distress syndrome. OBJECTIVES: To further understand the relative importance of mechanical power and driving pressure as clinical targets for ventilator management. DESIGN: Secondary observational analysis of randomized clinical trial data. SETTING AND PARTICIPANTS: Patients with the acute respiratory distress syndrome from three Acute Respiratory Distress Syndrome Network trials. MAIN OUTCOMES AND MEASURES: After adjusting for patient severity in a multivariate Cox proportional hazards model, we examined the relative association of driving pressure and mechanical power with hospital mortality. Among 2,410 patients, the relationship between driving pressure and mechanical power with mortality was modified by respiratory rate, positive end-expiratory pressure, and flow. RESULTS: Among patients with low respiratory rate (< 26), only power was significantly associated with mortality (power [hazard ratio, 1.82; 95% CI, 1.41-2.35; p < 0.001] vs driving pressure [hazard ratio, 1.01; 95% CI, 0.84-1.21; p = 0.95]), while among patients with high respiratory rate, neither was associated with mortality. Both power and driving pressure were associated with mortality at high airway flow (power [hazard ratio, 1.28; 95% CI, 1.15-1.43; p < 0.001] vs driving pressure [hazard ratio, 1.15; 95% CI, 1.01-1.30; p = 0.041]) and neither at low flow. At low positive end-expiratory pressure, neither was associated with mortality, whereas at high positive end-expiratory pressure (≥ 10 cm H2O), only power was significantly associated with mortality (power [hazard ratio, 1.22; 95% CI, 1.09-1.37; p < 0.001] vs driving pressure [hazard ratio, 1.16; 95% CI, 0.99-1.35; p = 0.059]). CONCLUSIONS AND RELEVANCE: The relationship between mechanical power and driving pressure with mortality differed within severity subgroups defined by positive end-expiratory pressure, respiratory rate, and airway flow.

Return to High Altitude After Recovery from Coronavirus Disease 2019.

Luks, Andrew M. and Colin K. Grissom. Return to high altitude after recovery from coronavirus disease 2019. High Alt Med Biol. 22: 119-127, 2021.-With the increasing availability of coronavirus disease 2019 (COVID-19) vaccines and the eventual decline in the burden of the disease, it is anticipated that all forms of tourism, including travel to high altitude, will rebound in the near future. Given the physiologic challenges posed by hypobaric hypoxia at high altitude, it is useful to consider whether high-altitude travel will pose risks to those previously infected with severe acute respiratory syndrome coronavirus 2, particularly those with persistent symptoms after resolution of their infection. Although no studies have specifically examined this question as of yet, available data on the cardiopulmonary sequelae of COVID-19 provide some sense of the problems people may face at high altitude and who warrants evaluation before such endeavors. On average, most individuals who have recovered from COVID-19 have normal or near normal gas exchange, pulmonary function testing, cardiovascular function, and exercise capacity, although a subset of individuals have persistent functional deficits in some or all of these domains when examined up to 5 months after infection. Evaluation is warranted before planned high-altitude travel in individuals with persistent symptoms at least 2 weeks after a positive test or hospital discharge as well as in those who required care in an intensive care unit or suffered from myocarditis or arterial or venous thromboembolism. Depending on the results of this testing, planned high-altitude travel may need to be modified or even deferred pending resolution of the identified abnormalities. As more people travel to high altitude after the pandemic and further studies are conducted, additional data should become available to provide further guidance on these issues.