Telemental Health Services Usage and Association with Health Care Utilization and Expenditures Among Vulnerable Medicare Beneficiaries in 2019: A Comparative Study Using Propensity Score Matching.

Background: Telemental health (TMH) offers a promising approach to managing major depressive disorder (MDD). The objective of our work was to evaluate TMH usage among a vulnerable population of MDD Medicare beneficiaries and its association with health care utilization and expenditures. Methods: This cohort study analyzed 2019 Mississippi Medicare fee-for-service data for adult beneficiaries with MDD. Subjects were matched by the use of TMH following 1:1 propensity score matching. Comparisons between TMH and non-TMH cohorts were made on health care utilization and expenditure outcomes, adjusting for provider types postmatching. Results: Among 7,673 identified beneficiaries, 551 used TMH and 7,122 did not. Prematching, TMH cohort showed greater proportions of dual beneficiaries, rural residents, subjects with income below $40,000, those with disability entitlement, and higher Charlson comorbidity index scores, compared to the non-TMH cohort (all p < 0.001). Moreover, the TMH cohort had fewer outpatient visits, but more inpatient admissions, emergency department (ED) visits, and higher medical, pharmacy, and total expenditures (all p < 0.001). Postmatching, TMH was associated with a 25% reduction in outpatient visits (p < 0.001) and a 20% reduction in pharmacy expenditures (p = 0.01), with no significant effect on inpatient admissions, ED visits, medical expenditures, or total expenditures. Conclusions: These results underscore the potential of TMH in enhancing accessible health care services for vulnerable populations and affordable services for Medicare. Our results provide a robust baseline for future policy discussions concerning TMH. Future studies should consider identifying barriers to TMH use among vulnerable populations and ensuring equitable and high-quality patient care.

Entropic Dynamics in a Theoretical Framework for Biosystems.

Central to an understanding of the physical nature of biosystems is an apprehension of their ability to control entropy dynamics in their environment. To achieve ongoing stability and survival, living systems must adaptively respond to incoming information signals concerning matter and energy perturbations in their biological continuum (biocontinuum). Entropy dynamics for the living system are then determined by the natural drive for reconciliation of these information divergences in the context of the constraints formed by the geometry of the biocontinuum information space. The configuration of this information geometry is determined by the inherent biological structure, processes and adaptive controls that are necessary for the stable functioning of the organism. The trajectory of this adaptive reconciliation process can be described by an information-theoretic formulation of the living system's procedure for actionable knowledge acquisition that incorporates the axiomatic inference of the Kullback principle of minimum information discrimination (a derivative of Jaynes' principle of maximal entropy). Utilizing relative information for entropic inference provides for the incorporation of a background of the adaptive constraints in biosystems within the operations of Fisher biologic replicator dynamics. This mathematical expression for entropic dynamics within the biocontinuum may then serve as a theoretical framework for the general analysis of biological phenomena.

A New Frontier in Telehealth Research: A National Telehealth Data Warehouse.

Importance: Given the rapid increase in telehealth utilization since the onset of the COVID-19 pandemic, it has become essential to examining the vast amount of available data on telehealth encounters to conduct more cogent, robust, and large-scope research studies to examine the utility, cost-impact, and effect on clinical outcomes that telehealth can potentially provide. However, the diversity of data collected by numerous telehealth organizations has made that type of analysis difficult. Objective: The University of Mississippi Medical Center (UMMC), a Telehealth Center of Excellence designated by the Health Resources and Services Administration, is creating a National Telehealth Data Warehouse. Design: UMMC will develop the data warehouse in Microsoft Azure and will use a data dictionary that was created by the Center for Telehealth and eHealth Law (CTeL) to support their national cost-benefit study on the use of telehealth during COVID-19. Impact: The data warehouse will provide unparalleled opportunities to conduct cost-benefit and cost-effectiveness analyses on telehealth, to develop and test quality measures specific to telehealth, and to understand how telehealth and reduce disparities in health care and expand access to care for everyone. The warehouse is expected to go live in the Summer of 2023.

Predictors of Metformin Failure: Repurposing Electronic Health Record Data to Identify High-Risk Patients.

CONTEXT: Metformin is the first-line drug for treating diabetes but has a high failure rate. OBJECTIVE: To identify demographic and clinical factors available in the electronic health record (EHR) that predict metformin failure. METHODS: A cohort of patients with at least 1 abnormal diabetes screening test that initiated metformin was identified at 3 sites (Arizona, Mississippi, and Minnesota). We identified 22 047 metformin initiators (48% female, mean age of 57 ± 14 years) including 2141 African Americans, 440 Asians, 962 Other/Multiracial, 1539 Hispanics, and 16 764 non-Hispanic White people. We defined metformin failure as either the lack of a target glycated hemoglobin (HbA1c) (<7%) within 18 months of index or the start of dual therapy. We used tree-based extreme gradient boosting (XGBoost) models to assess overall risk prediction performance and relative contribution of individual factors when using EHR data for risk of metformin failure. RESULTS: In this large diverse population, we observed a high rate of metformin failure (43%). The XGBoost model that included baseline HbA1c, age, sex, and race/ethnicity corresponded to high discrimination performance (C-index of 0.731; 95% CI 0.722, 0.740) for risk of metformin failure. Baseline HbA1c corresponded to the largest feature performance with higher levels associated with metformin failure. The addition of other clinical factors improved model performance (0.745; 95% CI 0.737, 0.754, P < .0001). CONCLUSION: Baseline HbA1c was the strongest predictor of metformin failure and additional factors substantially improved performance suggesting that routinely available clinical data could be used to identify patients at high risk of metformin failure who might benefit from closer monitoring and earlier treatment intensification.

Framework for Evaluating and Developing Sustainable Telehealth Programs.

During the COVID-19 pandemic and public health emergency, telehealth programs vastly expanded with strong support from various federal and state agencies. However, the uncertainty regarding future reimbursement policies for telehealth services has resulted in concerns about long-term sustainability of innovative health service delivery models beyond the financial support. Given the limited literature on creating telehealth programs with long-term sustainability in consideration, we have developed a framework for gathering appropriate data during various stages of program implementation to evaluate clinical effectiveness and economic sustainability that is applicable across various settings, with additional attention to health equity. Recognizing the difficulty of sustaining telehealth programs solely through a fee-for-service payment model, we encourage all telehealth stakeholders, especially payers and policymakers, to consider cost-effectiveness of telehealth programs and support alternate payment models for ensuring long-term sustainability.

In-Hospital Mortality Disparities Among American Indian and Alaska Native, Black, and White Patients With COVID-19.

Importance: American Indian and Alaska Native populations have some of the highest COVID-19 hospitalization and mortality rates in the US, with those in Mississippi being disparately affected. Higher COVID-19 mortality rates among Indigenous populations are often attributed to a higher comorbidity burden, although examinations of these associations are scarce, and none were believed to have included individuals hospitalized in Mississippi. Objective: To evaluate whether racial mortality differences among adults hospitalized with COVID-19 are associated with differential comorbidity experiences. Design, Setting, and Participants: The described cross-sectional study used retrospective hospital discharge data from the Mississippi Inpatient Outpatient Data System. All adult (aged ≥18 years) Mississippians of a known racial identity and who had been hospitalized with COVID-19 from March 1 to December 31, 2020, in any of the state's 103 nonfederal hospitals were included. Data were abstracted on June 17, 2021. Exposure: Racial identity. Main Outcomes and Measures: In-hospital mortality as indicated by discharge status. Results: A total of 18 731 adults hospitalized with a COVID-19 diagnosis and known racial identity were included (median age, 66 [IQR, 53-76] years; 10 109 [54.0%] female; 225 [1.2%] American Indian and Alaska Native; 9191 [49.1%] Black; and 9121 [48.7%] White). Pooling across comorbidity risk groups, odds of in-hospital mortality among Black patients were 75% lower than among American Indian and Alaska Native patients (odds ratio [OR], 0.25 [95% CI, 0.18-0.34]); odds of in-hospital death among White patients were 77% lower (OR, 0.23 [95% CI, 0.16-0.31]). Within comorbidity risk group analyses, Indigenous patients with the lowest risk (Elixhauser Comorbidity Index score ≤0) had an adjusted probability of in-hospital death of 0.10 compared with 0.03 for Black patients (OR, 0.29 [95% CI, 0.10-0.82]) and 0.04 for White patients (OR, 0.37 [95% CI, 0.13-1.07]). Probability of in-hospital death at the highest comorbidity risk levels (Elixhauser Comorbidity Index score ≥16) was 0.69 for American Indian and Alaska Native patients compared with 0.28 for Black patients (OR, 0.16 [95% CI, 0.08-0.32]) and 0.25 for White patients (OR, 0.14 [95% CI, 0.07-0.27]). Conclusions and Relevance: This cross-sectional study of US adults hospitalized with COVID-19 found that American Indian and Alaska Native patients had lower comorbidity risk scores than those observed among Black or White patients. Despite empirical associations between reduced comorbidity risk scores and reduced odds of inpatient mortality, American Indian and Alaska Native patients were significantly more likely to die in the hospital of COVID-19 than Black or White patients at every level of comorbidity risk. Alternative factors that may contribute to high mortality rates among Indigenous populations must be investigated.

COVID-19 Inpatient Mortality Disparities Among American Indian Adults in Mississippi's Safety Net Hospital.

BACKGROUND: Long-standing health disparities experienced by American Indians (AIs) are associated with increased all-cause mortality rates and shortened life expectancies when compared to other races and ethnicities. Nationally, these disparities have persisted with the COVID-19 pandemic as AIs are more likely than all other races to be infected, hospitalized, or die from SARS-CoV-2. The Mississippi Band of Choctaw Indians, the only federally recognized American Indian tribe in the state, has been one of the hardest hit in the nation. METHODS: Using de-identified data from the University of Mississippi Medical Center's COVID-19 Research Registry, a retrospective cohort study was conducted to assess COVID-19 inpatient mortality outcomes among adults (≥ age 18) admitted at the state's safety net hospital in 2020. RESULTS: Exactly 41% (n = 25) of American Indian adults admitted with a deemed diagnosis of COVID-19 died while in hospital, in comparison to 19% (n = 153) of blacks and 23% (n = 65) of whites. Racial disparities persisted even when controlling for those risk factors the CDC reported put adults at greatest risk of severe outcomes from the disease. The adjusted probability of inpatient mortality among American Indians was 46% (p < 0.00) in comparison to 19% among blacks and 20% among whites. CONCLUSION: Although comorbidities were commonly observed among COVID-19 + American Indian inpatients, only one was associated with inpatient mortality. This challenges commonly cited theories attributing disparate COVID-19 mortality experiences among indigenous populations to disparate comorbidity experiences. Expanded studies are needed to further investigate these associations.

Do Hospitals Providing Telehealth in Emergency Departments Have Lower Emergency Department Costs?

Background: Since 2003, the University of Mississippi Medical Center has operated a robust telehealth emergency department (ED) network, TelEmergency, which enhances access to emergency medicine-trained physicians at participating rural hospitals. TelEmergency was developed as a cost-control measure for financially constrained rural hospitals to improve access to quality, emergency care. However, the literature remains unclear as to whether ED telehealth services can be provided at lower costs compared with traditional in-person ED services. Introduction: Our objective was to empirically determine whether TelEmergency was associated with lower ED costs at rural hospitals when compared with similar hospitals without TelEmergency between 2010 and 2017. Materials and Methods: A panel of data for 2010-2017 was constructed at the hospital level. Hospitals with TelEmergency (n = 14 hospitals; 112 hospital-years) were compared with similar hospitals that did not use TelEmergency from Arkansas, Georgia, Mississippi, and South Carolina (n = 102; 766 hospital-years), matched using Coarsened Exact Matching. The relationship between total ED costs and treatment (e.g., participation in TelEmergency) was predicted using generalized estimating equations with a Poisson distribution, a log link, an exchangeable error term, and robust standard errors. Results: After controlling for ownership type, critical access hospital status, year, and size, TelEmergency was associated with an estimated 31.4% lower total annual ED costs compared with similar matched hospitals that did not provide TelEmergency. Conclusions: TelEmergency utilization was associated with significantly lower total annual ED costs compared with similarly matched hospitals that did not utilize TelEmergency. These findings suggest that access to quality ED care in rural communities can occur at lower costs.

The impact of the TelEmergency program on rural emergency care: An implementation study.

Introduction Timely, appropriate intervention is key to improving outcomes in many emergent conditions. In rural areas, it is particularly challenging to assure quality, timely emergency care. The TelEmergency (TE) program, which utilizes a dual nurse practitioner and emergency medicine-trained, board-certified physician model, has the potential to improve access to quality emergency care in rural areas. The objective of this study was to examine how the implementation of the TE program impacts rural hospital Emergency Department (ED) operations. Methods Methods included a before and after study of the effect of the TE program on participating rural hospitals between January 2007 and December 2008. Data on ED and hospital operations were collected one year prior to and one year following the implementation of TE. Data from participating hospitals were combined and compared for the two time periods. Results Nine hospitals met criteria for inclusion and participated in the study. Total ED volumes did not significantly change with TE implementation, but ED admissions to the same rural hospital significantly increased following TE implementation (6.7% to 8.1%, p-value = 0.02). Likewise, discharge rates from the ED declined post-initiation (87.1% to 80.0%, p-value = 0.003). ED deaths and transfer rates showed no significant change, while the rate of patient discharge against medical advice significantly increased with TE use. Discussion In this analysis, we found a significant increase in the rate of ED admissions to rural hospitals with TE use. These findings may have important implications for the quality of emergency care in rural areas and the sustainability of rural hospitals' EDs.

Emergent Bleeding in Patients Receiving Direct Oral Anticoagulants.

Direct oral anticoagulants (DOACs) offer clinical advantages over warfarin, such as minimal medication and food interactions and fixed dosing without the need for routine monitoring of coagulation status. As with all anticoagulants, bleeding, either spontaneous or provoked, is the most common complication. The long-term use of these drugs is increasing, and there is a crucial need for emergency medicine service professionals to understand the optimal management of associated bleeding. This review aims to describe the indications and pharmacokinetics of available DOACs; to discuss the risk of bleeding; to provide a treatment algorithm to manage DOAC-associated emergency bleeding; and to discuss future directions in bleeding management, including the role of specific reversal agents, such as the recently approved idarucizumab for reversal of the direct thrombin inhibitor dabigatran. Because air medical personnel are increasingly likely to encounter patients receiving DOACs, it is important that they have an understanding of how to manage patients with emergent bleeding.

Validation of the Sonographic Ottawa Foot and Ankle Rules (SOFAR) Study in a Large Urban Trauma Center.

INTRODUCTION: Differentiating the severity of acute ankle injuries is a common problem in the emergency department (ED). The Ottawa Foot and Ankle Rules (OFAR) were designed to obviate the need for unnecessary x-rays. Although these rules have been determined to be very sensitive, they lack the specificity necessary to make them practically useful for a condition in which a misdiagnosis could result in a significant disability. Our study objective was to determine if the addition of a bedside ultrasound (US) to the evaluation process could be used to significantly reduce the number of negative x-rays in OFAR positive patients. METHODS: A prospective observational studywas conducted in a Level I urban trauma center over a 12 month period in which bedside US was utilized to detect foot and/or ankle fractures in OFAR positive patients of age 18 years and older. All patients in the study received foot and/or ankle x-rays based on OFAR exam. Prior to viewing the x-rays, trained clinicians performed bedside US targeting the medial and lateral malleoli, navicular, and base of the 5th metatarsal and provided a diagnostic impression based on their US findings. The US findings were then compared to the formal x-ray interpretation. RESULTS: A total of fifty patients was enrolled into the study of which twenty-one patients were discovered to have a fracture by US. The sensitivity ofUS in detecting foot and/or ankle fractures was 100% (95% Confidence Interval [CI] 78%-100%) and the specificity of OFAR increased from 50% (95% CI 37%-63%) to 100% (95% CI 87%-100%) with the addition of US. The negative predictive value was 100% (95% CI 89%-100%), and the positive predictive value was 100% (95% CI 81%-100%). CONCLUSIONS: Among OFAR positive patients, bedside US has high sensitivity and specificity for detecting foot and/or ankle fractures. Further studies should be conducted to determine if utilizing bedside US in addition to OFAR could significantly reduce the number of x-rays and improve the efficiency and costs associated with evaluating these injuries in the ED. Implication for health policy/medical education/research/ practice. Utilizing bedside ultrasonography in addition to Ottawa Foot and Ankle Rules in acutely injured patients could significantly reduce the number of ordered x-rays and length of stay in the emergency department.

Theoretical Analysis of the Relative Impact of Obesity on Hemodynamic Stability During Acute Hemorrhagic Shock.

BACKGROUND: Evidence suggests that morbid obesity may be an independent risk factor for adverse outcomes in patients with traumatic injuries. OBJECTIVES: In this study, a theoretic analysis using a derivation of the Guyton model of cardiovascular physiology examines the expected impact of obesity on hemodynamic changes in Mean Arterial Pressure (MAP) and Cardiac Output (CO) during Hemorrhagic Shock (HS). PATIENTS AND METHODS: Computer simulation studies were used to predict the relative impact of increasing Body Mass Index (BMI) on global hemodynamic parameters during HS. The analytic procedure involved recreating physiologic conditions associated with changing BMI for a virtual subject in an In Silico environment. The model was validated for the known effect of a BMI of 30 on iliofemoral venous pressures. Then, the relative effect of changing BMI on the outcome of target cardiovascular parameters was examined during simulated acute loss of blood volume in class II hemorrhage. The percent changes in these parameters were compared between the virtual nonobese and obese subjects. Model parameter values are derived from known population distributions, producing simulation outputs that can be used in a deductive systems analysis assessment rather than traditional frequentist statistical methodologies. RESULTS: In hemorrhage simulation, moderate increases in BMI were found to produce greater decreases in MAP and CO compared to the normal subject. During HS, the virtual obese subject had 42% and 44% greater falls in CO and MAP, respectively, compared to the nonobese subject. Systems analysis of the model revealed that an increase in resistance to venous return due to changes in intra-abdominal pressure resulting from obesity was the critical mechanism responsible for the differences. CONCLUSIONS: This study suggests that obese patients in HS may have a higher risk of hemodynamic instability compared to their nonobese counterparts primarily due to obesity-induced increases in intra-abdominal pressure resulting in reduced venous return.

Prevalence of intubation rescue by air medical personnel during transfers from rural emergency departments.

OBJECTIVE: Non-emergency-trained providers in rural emergency departments (ED) often lack the skills required for emergency resuscitations and rely on air medical transport teams to provide the initial airway stabilization of these patients. In this study, we determined the prevalence with which endotracheal intubations are required of air medical personnel upon arrival to rural EDs including intubations that were first attempted by the local provider. METHODS: A retrospective database review was conducted of all air medical transfers from rural hospitals for a 28-month period. Those patients requiring an airway were categorized according to which provider initiated the intubation procedure. The prevalence of intubations performed by air medical and local providers was recorded as the percent of the total number of intubations. RESULTS: There were a total of 217 patients from 11 rural EDs requiring airway support. Air medical personnel were responsible for 85% of the intubations. Alternative airway support was necessary in 5% of the patients after unsuccessful intubation attempts. The failed intubations tended to be slightly older and female. CONCLUSION: Our study suggests that the vast majority of the intubations for patients requiring a helicopter evacuation from these rural settings are performed by the air medical personnel.

The effect of early quantitative resuscitation on organ function in survivors of septic shock.

OBJECTIVE: The objective of this study is to determine if early quantitative resuscitation (QR) attenuates organ dysfunction in survivors of septic shock. METHODS: This is a secondary analysis of a completed implementation study. Inclusion criteria are suspected infection, greater than or equal to 2 systemic inflammatory response syndrome criteria and either systolic blood pressure less than 90 mm Hg after a fluid bolus or lactate more than 4 mmol/L and survival to hospital discharge. Data were prospectively collected on eligible patients for 1 year before and 3 years after implementation of early QR. Patients in the before phase received nonprotocolized care (NPC) at physician discretion. Survivors who received QR were compared with survivors who received NPC. The primary outcome was the worst sequential organ failure assessment (SOFA) score during hospitalization. RESULTS: Two hundred sixty patients in the QR group and 41 patients in the NPC group were included. There were no significant differences in demographics between the 2 groups. The initial SOFA score in the QR group was 6 and in the NPC group was 6 (P = .17). There was no significant difference in the worst SOFA score during hospitalization between the QR and NPC groups (6 vs 6, respectively; P = .16). CONCLUSIONS: In survivors of septic shock, we found no difference in maximal organ dysfunction during hospitalization between patients who received QR vs NPC.

Functionality of empirical model-based predictive analytics for the early detection of hemodynamic instabilty.

UNLABELLED: Background. Monitoring cardiovascular hemodynamics in the modern clinical setting is a major challenge. Increasing amounts of physiologic data must be analyzed and interpreted in the context of the individual patient’s pathology and inherent biologic variability. Certain data-driven analytical methods are currently being explored for smart monitoring of data streams from patients as a first tier automated detection system for clinical deterioration. As a prelude to human clinical trials, an empirical multivariate machine learning method called Similarity-Based Modeling (“SBM”), was tested in an In Silico experiment using data generated with the aid of a detailed computer simulator of human physiology (Quantitative Circulatory Physiology or “QCP”) which contains complex control systems with realistic integrated feedback loops. Methods. SBM is a kernel-based, multivariate machine learning method that that uses monitored clinical information to generate an empirical model of a patient’s physiologic state. This platform allows for the use of predictive analytic techniques to identify early changes in a patient’s condition that are indicative of a state of deterioration or instability. The integrity of the technique was tested through an In Silico experiment using QCP in which the output of computer simulations of a slowly evolving cardiac tamponade resulted in progressive state of cardiovascular decompensation. Simulator outputs for the variables under consideration were generated at a 2-min data rate (0.083Hz) with the tamponade introduced at a point 420 minutes into the simulation sequence. The functionality of the SBM predictive analytics methodology to identify clinical deterioration was compared to the thresholds used by conventional monitoring methods. Results. The SBM modeling method was found to closely track the normal physiologic variation as simulated by QCP. With the slow development of the tamponade, the SBM model are seen to disagree while the simulated biosignals in the early stages of physiologic deterioration and while the variables are still within normal ranges. Thus, the SBM system was found to identify pathophysiologic conditions in a timeframe that would not have been detected in a usual clinical monitoring scenario. Conclusion. In this study the functionality of a multivariate machine learning predictive methodology that that incorporates commonly monitored clinical information was tested using a computer model of human physiology. SBM and predictive analytics were able to differentiate a state of decompensation while the monitored variables were still within normal clinical ranges. This finding suggests that the SBM could provide for early identification of a clinical deterioration using predictive analytic techniques. KEYWORDS: predictive analytics, hemodynamic, monitoring.

Characteristics and outcomes of patients with vasoplegic versus tissue dysoxic septic shock.

BACKGROUND: The current consensus definition of septic shock requires hypotension after adequate fluid challenge or vasopressor requirement. Some patients with septic shock present with hypotension and hyperlactatemia greater than 2 mmol/L (tissue dysoxic shock), whereas others have hypotension alone with normal lactate (vasoplegic shock). OBJECTIVE: The objective of this study was to determine differences in outcomes of patients with tissue dysoxic versus vasoplegic septic shock. METHODS: This was a secondary analysis of a large, multicenter randomized controlled trial. Inclusion criteria were suspected infection, two or more systemic inflammatory response criteria, and systolic blood pressure less than 90 mmHg after a fluid bolus. Patients were categorized by presence of vasoplegic or tissue dysoxic shock. Demographics and Sequential Organ Failure Assessment scores were evaluated between the groups. The primary outcome was in-hospital mortality. RESULTS: A total of 247 patients were included, 90 patients with vasoplegic shock and 157 with tissue dysoxic shock. There were no significant differences in age, race, or sex between the vasoplegic and tissue dysoxic shock groups. The group with vasoplegic shock had a lower initial Sequential Organ Failure Assessment score than did the group with tissue dysoxic shock (5.5 vs. 7.0 points; P = 0.0002). The primary outcome of in-hospital mortality occurred in 8 (9%) of 90 patients with vasoplegic shock compared with 41 (26%) of 157 in the group with tissue dysoxic shock (proportion difference, 17%; 95% confidence interval, 7%-26%; P < 0.0001; log-rank test P = 0.02). After adjusting for confounders, tissue dysoxic shock remained an independent predictor of in-hospital mortality. CONCLUSIONS: In this analysis of patients with septic shock, we found a significant difference in in-hospital mortality between patients with vasoplegic versus tissue dysoxic septic shock. These findings suggest a need to consider these differences when designing future studies of septic shock therapies.

Characterization of the spectrum of hemodynamic profiles in trauma patients with acute neurogenic shock.

OBJECTIVE: Neurogenic shock considered a distributive type of shock secondary to loss of sympathetic outflow to the peripheral vasculature. In this study, we examine the hemodynamic profiles of a series of trauma patients with a diagnosis of neurogenic shock. METHODS: Hemodynamic data were collected on a series of trauma patients determined to have spinal cord injuries with neurogenic shock. A well-established integrated computer model of human physiology was used to analyze and categorize the hemodynamic profiles from a system analysis perspective. A differentiation between these categories was presented as the percent of total patients. RESULTS: Of the 9 patients with traumatic neurogenic shock, the etiology of shock was decrease in peripheral vascular resistance (PVR) in 3 (33%; 95% confidence interval, 12%-65%), loss of vascular capacitance in 2 (22%; 6%-55%) and mixed peripheral resistance and capacitance responsible in 3 (33%; 12%-65%), and purely cardiac in 1 (11%; 3%-48%). The markers of sympathetic outflow had no correlation to any of the elements in the patients' hemodynamic profiles. CONCLUSIONS: Results from this study suggest that hypotension of neurogenic shock can have multiple mechanistic etiologies and represents a spectrum of hemodynamic profiles. This understanding is important for the treatment decisions in managing these patients.