Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 168
Filtrar
1.
Transfusion ; 61 Suppl 1: S174-S182, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34269446

RESUMO

BACKGROUND: The Compensatory Reserve Measurement (CRM) is a novel method used to provide early assessment of shock based on arterial wave form morphology changes. We hypothesized that (1) CRM would be significantly lower in those trauma patients who received life-saving interventions compared with those not receiving interventions, and (2) CRM in patients who received interventions would recover after the intervention was performed. STUDY DESIGN AND METHODS: We captured vital signs along with analog arterial waveform data from trauma patients meeting major activation criteria using a prospective study design. Study team members tracked interventions throughout their emergency department stay. RESULTS: Ninety subjects met inclusion with 13 receiving a blood product and 10 a major airway intervention. Most trauma was blunt (69%) with motor vehicle collisions making up the largest proportion (37%) of injury mechanism. Patients receiving blood products had lower CRM values just prior to administration versus those who did not (50% versus 58%, p = .045), and lower systolic pressure (SBP; 95 versus 123 mmHg, p = .005), diastolic (DBP; 62 versus 79, p = .007), and mean arterial pressure (MAP; 75 versus 95, p = .006), and a higher pulse rate (HR; 101 versus 89 bpm, p = .039). Patients receiving an airway intervention had lower CRM values just prior to administration versus those who did not (48% versus 58%, p = .062); however, SBP, DBP, MAP, and HR were not statistically distinguishable (p ≥ .645). CONCLUSIONS: Our results support our hypotheses that the CRM distinguished those patients who received blood or an airway intervention from those who did not, and increased appropriately after interventions were performed.


Assuntos
Ferimentos e Lesões/diagnóstico , Ferimentos e Lesões/terapia , Adulto , Pressão Arterial , Pressão Sanguínea , Transfusão de Sangue , Serviço Hospitalar de Emergência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Ressuscitação/métodos , Choque Traumático/diagnóstico , Choque Traumático/terapia , Ferimentos e Lesões/fisiopatologia
2.
Transfusion ; 61 Suppl 1: S167-S173, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34269439

RESUMO

INTRODUCTION: We conducted a prospective observational study on 205 trauma patients at a level I trauma facility to test the hypothesis that a compensatory reserve measurement (CRM) would identify higher risk for progression to shock and/or need a life-saving interventions (LSIs) earlier than systolic blood pressure (SBP) and blood lactate (LAC). METHODS: A composite outcome metric included blood transfusion, procedural LSI, and mortality. Discrete measures assessed as abnormal (ab) were SBP <90 mmHg, CRM <60%, and LAC >2.0. A graded categorization of shock was defined as: no shock (normal [n] SBP [n-SBP], n-CRM, n-LAC); sub-clinical shock (ab-CRM, n-SBP, n-LAC); occult shock (n-SBP, ab-CRM, ab-LAC); or overt shock (ab-SBP, ab-CRM, ab-LAC). RESULTS: Three patients displayed overt shock, 53 displayed sub-clinical shock, and 149 displayed no shock. After incorporating lactate into the analysis, 86 patients demonstrated no shock, 25 were classified as sub-clinical shock, 91 were classified as occult shock, and 3 were characterized as overt shock. Each shock subcategory revealed a graded increase requiring LSI and transfusion. Initial CRM was associated with progression to shock (odds ratio = 0.97; p < .001) at an earlier time than SBP or LAC. CONCLUSIONS: Initial CRM uncovers a clinically relevant subset of patients who are not detected by SBP and LAC. Our results suggest CRM could be used to more expeditiously identify injured patients likely to deteriorate to shock, with requirements for blood transfusion or procedural LSI.


Assuntos
Transfusão de Sangue , Hemorragia/terapia , Choque Hemorrágico/terapia , Ferimentos e Lesões/terapia , Pressão Sanguínea , Feminino , Hemorragia/sangue , Hemorragia/diagnóstico , Hemorragia/fisiopatologia , Humanos , Lactatos/sangue , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Choque Hemorrágico/sangue , Choque Hemorrágico/diagnóstico , Choque Hemorrágico/fisiopatologia , Triagem , Ferimentos e Lesões/sangue , Ferimentos e Lesões/diagnóstico , Ferimentos e Lesões/fisiopatologia
3.
J Trauma Acute Care Surg ; 91(2S Suppl 2): S33-S39, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34039933

RESUMO

ABSTRACT: Traumatic brain injury (TBI) is associated with increased morbidity and mortality in civilian trauma and battlefield settings. It has been classified across a continuum of dysfunctions, with as much as 80% to 90% of cases diagnosed as mild to moderate in combat casualties. In this report, a framework is presented that focuses on the potential benefits for acute noninvasive treatment of reduced cerebral perfusion associated with mild TBI by harnessing the natural transfer of negative intrathoracic pressure during inspiration. This process is known as intrathoracic pressure regulation (IPR) therapy, which can be applied by having a patient breath against a small inspiratory resistance created by an impedance threshold device. Intrathoracic pressure regulation therapy leverages two fundamental principles for improving blood flow to the brain: (1) greater negative intrathoracic pressure enhances venous return, cardiac output, and arterial blood pressure; and (2) lowering of intracranial pressure provides less resistance to cerebral blood flow. These two effects work together to produce a greater pressure gradient that results in an improvement in cerebral perfusion pressure. In this way, IPR therapy has the potential to counter hypotension and hypoxia, potentially significant contributing factors to secondary brain injury, particularly in conditions of multiple injuries that include severe hemorrhage. By implementing IPR therapy in patients with mild-to-moderate TBI, a potential exists to provide early neuroprotection at the point of injury and a bridge to more definitive care, particularly in settings of prolonged delays in evacuation such as those anticipated in future multidomain operations. LEVEL OF EVIDENCE: Report.


Assuntos
Lesões Encefálicas Traumáticas/terapia , Circulação Cerebrovascular/fisiologia , Lesões Encefálicas Traumáticas/etiologia , Lesões Encefálicas Traumáticas/fisiopatologia , Hemodinâmica/fisiologia , Humanos , Respiração , Ressuscitação/métodos , Lesões Relacionadas à Guerra/fisiopatologia , Lesões Relacionadas à Guerra/terapia
4.
Compr Physiol ; 11(1): 1531-1574, 2021 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-33577122

RESUMO

Hemorrhage is a leading cause of death following traumatic injuries in the United States. Much of the previous work in assessing the physiology and pathophysiology underlying blood loss has focused on descriptive measures of hemodynamic responses such as blood pressure, cardiac output, stroke volume, heart rate, and vascular resistance as indicators of changes in organ perfusion. More recent work has shifted the focus toward understanding mechanisms of compensation for reduced systemic delivery and cellular utilization of oxygen as a more comprehensive approach to understanding the complex physiologic changes that occur following and during blood loss. In this article, we begin with applying dimensional analysis for comparison of animal models, and progress to descriptions of various physiological consequences of hemorrhage. We then introduce the complementary side of compensation by detailing the complexity and integration of various compensatory mechanisms that are activated from the initiation of hemorrhage and serve to maintain adequate vital organ perfusion and hemodynamic stability in the scenario of reduced systemic delivery of oxygen until the onset of hemodynamic decompensation. New data are introduced that challenge legacy concepts related to mechanisms that underlie baroreflex functions and provide novel insights into the measurement of the integrated response of compensation to central hypovolemia known as the compensatory reserve. The impact of demographic and environmental factors on tolerance to hemorrhage is also reviewed. Finally, we describe how understanding the physiology of compensation can be translated to applications for early assessment of the clinical status and accurate triage of hypovolemic and hypotensive patients. © 2021 American Physiological Society. Compr Physiol 11:1531-1574, 2021.

5.
Mil Med ; 186(5-6): e474-e479, 2021 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-33169135

RESUMO

INTRODUCTION: The Committee on Tactical Combat Casualty Care and Capabilities Development and Integration Directorate cite airway burn injuries as an indication for prehospital cricothyrotomy. We sought to build on previously published data by describing for the first time the incidence of prehospital airway interventions in combat casualties who received airway management in the setting of inhalational injuries.15,26 We hypothesized that (1) airway interventions in combat casualties who suffered inhalational injury would have a higher mortality rate than those without airway intervention and (2) prehospital cricothyrotomy was used with greater incidence than endotracheal intubation. MATERIALS AND METHODS: Using a previously described Department of Defense Trauma Registry dataset from January 2007 to August 2016, unique casualties with documented inhalational injury were identified. RESULTS: Our predefined search codes captured 28,222 (72.8% of all encounters in the registry) of those subjects. A total of 347 (1.2%) casualties had a documented inhalational injury, 27 (7.8%) of those with at least 1 prehospital airway intervention inhalational injuries (0.09% of our dataset [n = 28,222]). Within the subset of patients with an inhalation injury, 23 underwent intubation, 2 underwent cricothyrotomy, 3 had placement of an airway adjunct not otherwise specifically listed, and 1 casualty had both a cricothyrotomy and intubation documented. No casualties had a supraglottic, nasopharyngeal, or oropharyngeal airway listed. Contrary to our hypotheses, of those with an airway intervention, 74.0% survived to hospital discharge. In multivariable regression models, when adjusting for confounders, there was no difference in survival to discharge in those with an airway intervention compared to those without. CONCLUSIONS: Casualties undergoing airway intervention for inhalation injuries had similar survival adjusting for injury severity, supporting its role when indicated. Without case-specific data on airway status and interventions, it is challenging to determine if the low rate of cricothyrotomy in this population was a result of rapid transport to a more advanced provider capable of performing intubation or cricothyrotomy may not be meeting the needs of the medics.


Assuntos
Serviços Médicos de Emergência , Lesão por Inalação de Fumaça , Ferimentos e Lesões , Manuseio das Vias Aéreas , Humanos , Intubação Intratraqueal , Sistema de Registros , Lesão por Inalação de Fumaça/terapia
6.
Mil Med ; 2020 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-33242098

RESUMO

INTRODUCTION: The Prehospital Trauma Registry (PHTR) captures after-action reviews (AARs) as part of a continuous performance improvement cycle and to provide commanders real-time feedback of Role 1 care. We have previously described overall challenges noted within the AARs. We now performed a focused assessment of challenges with regard to hemodynamic monitoring to improve casualty monitoring systems. MATERIALS AND METHODS: We performed a review of AARs within the PHTR in Afghanistan from January 2013 to September 2014 as previously described. In this analysis, we focus on AARs specific to challenges with hemodynamic monitoring of combat casualties. RESULTS: Of the 705 PHTR casualties, 592 had available AAR data; 86 of those described challenges with hemodynamic monitoring. Most were identified as male (97%) and having sustained battle injuries (93%), typically from an explosion (48%). Most were urgent evacuation status (85%) and had a medical officer in their chain of care (65%). The most common vital sign mentioned in AAR comments was blood pressure (62%), and nearly one-quarter of comments stated that arterial palpation was used in place of blood pressure cuff measurements. CONCLUSIONS: Our qualitative methods study highlights the challenges with obtaining vital signs-both training and equipment. We also highlight the challenges regarding ongoing monitoring to prevent hemodynamic collapse in severely injured casualties. The U.S. military needs to develop better methods for casualty monitoring for the subset of casualties that are critically injured.

7.
Sensors (Basel) ; 20(22)2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33182638

RESUMO

Vital signs historically served as the primary method to triage patients and resources for trauma and emergency care, but have failed to provide clinically-meaningful predictive information about patient clinical status. In this review, a framework is presented that focuses on potential wearable sensor technologies that can harness necessary electronic physiological signal integration with a current state-of-the-art predictive machine-learning algorithm that provides early clinical assessment of hypovolemia status to impact patient outcome. The ability to study the physiology of hemorrhage using a human model of progressive central hypovolemia led to the development of a novel machine-learning algorithm known as the compensatory reserve measurement (CRM). Greater sensitivity, specificity, and diagnostic accuracy to detect hemorrhage and onset of decompensated shock has been demonstrated by the CRM when compared to all standard vital signs and hemodynamic variables. The development of CRM revealed that continuous measurements of changes in arterial waveform features represented the most integrated signal of physiological compensation for conditions of reduced systemic oxygen delivery. In this review, detailed analysis of sensor technologies that include photoplethysmography, tonometry, ultrasound-based blood pressure, and cardiogenic vibration are identified as potential candidates for harnessing arterial waveform analog features required for real-time calculation of CRM. The integration of wearable sensors with the CRM algorithm provides a potentially powerful medical monitoring advancement to save civilian and military lives in emergency medical settings.


Assuntos
Hemorragia/diagnóstico , Hipovolemia , Monitorização Fisiológica/instrumentação , Dispositivos Eletrônicos Vestíveis , Ferimentos e Lesões/diagnóstico , Algoritmos , Hemodinâmica , Humanos , Hipovolemia/diagnóstico
8.
J Spec Oper Med ; 20(3): 97-102, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32969011

RESUMO

Based on limited published evidence, physiological principles, clinical experience, and expertise, the author group has developed a consensus statement on the potential for iatrogenic harm with rapid sequence induction (RSI) intubation and positive-pressure ventilation (PPV) on patients in hemorrhagic shock. "In hemorrhagic shock, or any low flow (central hypovolemic) state, it should be noted that RSI and PPV are likely to cause iatrogenic harm by decreasing cardiac output." The use of RSI and PPV leads to an increased burden of shock due to a decreased cardiac output (CO)2 which is one of the primary determinants of oxygen delivery (DO2). The diminishing DO2 creates a state of systemic hypoxia, the severity of which will determine the magnitude of the shock (shock dose) and a growing deficit of oxygen, referred to as oxygen debt. Rapid accumulation of critical levels of oxygen debt results in coagulopathy and organ dysfunction and failure. Spontaneous respiration induced negative intrathoracic pressure (ITP) provides the pressure differential driving venous return. PPV subsequently increases ITP and thus right atrial pressure. The loss in pressure differential directly decreases CO and DO2 with a resultant increase in systemic hypoxia. If RSI and PPV are deemed necessary, prior or parallel resuscitation with blood products is required to mitigate post intervention reduction of DO2 and the potential for inducing cardiac arrest in the critically shocked patient.


Assuntos
Choque Hemorrágico , Humanos , Consumo de Oxigênio , Respiração com Pressão Positiva/efeitos adversos , Indução e Intubação de Sequência Rápida , Ressuscitação , Choque Hemorrágico/etiologia , Choque Hemorrágico/terapia
9.
Transfusion ; 60 Suppl 3: S62-S69, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32478865

RESUMO

BACKGROUND: The physiological response to hemorrhage includes vasoconstriction in an effort to shunt blood to the heart and brain. Hemorrhaging patients can be classified as "good" compensators who demonstrate high tolerance (HT) or "poor" compensators who manifest low tolerance (LT) to central hypovolemia. Compensatory vasoconstriction is manifested by lower tissue oxygen saturation (StO2 ), which has propelled this measure as a possible early marker of shock. The compensatory reserve measurement (CRM) has also shown promise as an early indicator of decompensation. METHODS: Fifty-one healthy volunteers (37% LT) were subjected to progressive lower body negative pressure (LBNP) as a model of controlled hemorrhage designed to induce an onset of decompensation. During LBNP, CRM was determined by arterial waveform feature analysis. StO2 , muscle pH, and muscle H+ concentration were calculated from spectrum using near-infrared spectroscopy (NIRS) on the forearm. RESULTS: These values were statistically indistinguishable between HT and LT participants at baseline (p ≥ 0.25). HT participants exhibited lower (p = 0.01) StO2 at decompensation compared to LT participants. CONCLUSIONS: Lower StO2 measured in patients during low flow states associated with significant hemorrhage does not necessarily translate to a more compromised physiological state, but may reflect a greater resistance to the onset of shock. Only the CRM was able to distinguish between HT and LT participants early in the course of hemorrhage, supported by a significantly greater ROC AUC (0.90) compared with STO2 (0.68). These results support the notion that measures of StO2 could be misleading for triage and resuscitation decision support.

10.
Transfusion ; 60 Suppl 3: S150-S157, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32478902

RESUMO

Hemorrhagic shock can be mitigated by timely and accurate resuscitation designed to restore adequate delivery of oxygen (DO2 ). Current doctrine of using systolic blood pressure (SBP) as a guide for resuscitation can be associated with increased morbidity. The compensatory reserve measurement (CRM) is a novel vital sign based on the recognition that the sum of all mechanisms that contribute to the compensatory response to hemorrhage reside in features of the arterial pulse waveform. CRM can be assessed continuously and non-invasively in real time. Compared to standard vital signs, CRM provides an early, as well as more sensitive and specific, indicator of patient hemorrhagic status since the activation of compensatory mechanisms occurs immediately at the onset of blood loss. Recent data obtained from our laboratory experiments on non-human primates have demonstrated that CRM is linearly related to DO2 during controlled progressive hemorrhage and subsequent whole blood resuscitation. We used this relationship to determine that the time of hemodynamic decompensation (i.e., CRM = 0%) is defined by a critical DO2 at approximately 5.3 mL O2 ∙kg-1 ∙min-1 . We also demonstrated that a target CRM of 35% during whole blood resuscitation only required replacement of 40% of the total blood volume loss to adequately sustain a DO2 more than 50% (i.e., 8.1 mL O2 ∙kg-1 ∙min-1 ) above critical DO2 (i.e., threshold for decompensated shock) while maintaining hypotensive resuscitation (i.e., SBP at ~90 mmHg). Consistent with our hypothesis, specific values of CRM can be used to accurately maintain DO2 thresholds above critical DO2 , avoiding the onset of hemorrhagic shock with whole blood resuscitation.

11.
PLoS One ; 15(6): e0234844, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32579572

RESUMO

BACKGROUND: To study central hypovolemia in humans, lower body negative pressure (LBNP) is a recognized alternative to blood removal (HEM). While LBNP mimics the cardiovascular responses of HEM in baboons, similarities in hemostatic responses to LBNP and HEM remain unknown in this species. METHODS: Thirteen anesthetized baboons were exposed to progressive hypovolemia by HEM and, four weeks later, by LBNP. Hemostatic activity was evaluated by plasma markers, thromboelastography (TEG), flow cytometry, and platelet aggregometry at baseline (BL), during and after hypovolemia. RESULTS: BL values were indistinguishable for most parameters although platelet count, maximal clot strength (MA), protein C, thrombin anti-thrombin complex (TAT), thrombin activatable fibrinolysis inhibitor (TAFI) activity significantly differed between HEM and LBNP. Central hypovolemia induced by either method activated coagulation; TEG R-time decreased and MA increased during and after hypovolemia compared to BL. Platelets displayed activation by flow cytometry; platelet count and functional aggregometry were unchanged. TAFI activity and protein, Factors V and VIII, vWF, Proteins C and S all demonstrated hemodilution during HEM and hemoconcentration during LBNP, whereas tissue plasminogen activator (tPA), plasmin/anti-plasmin complex, and plasminogen activator inhibitor-1 did not. Fibrinolysis (TEG LY30) was unchanged by either method; however, at BL, fibrinolysis varied greatly. Post-hoc analysis separated baboons into low-lysis (LY30 <2%) or high-lysis (LY30 >2%) whose fibrinolytic state matched at both HEM and LBNP BL. In high-lysis, BL tPA and LY30 correlated strongly (r = 0.95; P<0.001), but this was absent in low-lysis. In low-lysis, BL TAFI activity and tPA correlated (r = 0.88; P<0.050), but this was absent in high-lysis. CONCLUSIONS: Central hypovolemia induced by either LBNP or HEM resulted in activation of coagulation; thus, LBNP is an adjunct to study hemorrhage-induced pro-coagulation in baboons. Furthermore, this study revealed a subset of baboons with baseline hyperfibrinolysis, which was strongly coupled to tPA and uncoupled from TAFI activity.


Assuntos
Fibrinólise , Hemorragia/complicações , Hemostasia , Hipovolemia/tratamento farmacológico , Hipovolemia/fisiopatologia , Pressão Negativa da Região Corporal Inferior/efeitos adversos , Animais , Masculino , Papio
12.
J Trauma Acute Care Surg ; 89(2S Suppl 2): S153-S160, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32118823

RESUMO

BACKGROUND: Sepsis, a leading cause of morbidity and mortality worldwide, characterized by metabolic and hemodynamic changes that can lead to multiorgan failure and death. The evaluation of a patient's condition is routinely performed by several objective criteria. The compensatory reserve measurement (CRM) represents a new paradigm that measures the total of all physiological compensatory mechanisms, using noninvasive photoplethysmography to read changes in arterial waveforms. The present study's aim was to evaluate the applicability and the predictive value of the CRM during sepsis. METHODS: Data were prospectively collected from patients hospitalized in the department of surgery because of different inflammatory illnesses. All subjects were evaluated with hemodynamic, laboratory measurements and CRM throughout hospitalization. RESULTS: Of 100 subjects enrolled, 84 patients were not septic. The remaining 16 patients were in sepsis (Sequential Organ Failure Assessment [SOFA] score, >2), 6 of whom were in septic shock and 4 died. When nonseptic patients were compared with septic patients, statistical differences were found in C-reactive protein level (p < 0.0005), SOFA score (p < 0.0005), and CRM (p < 0.0001). Other parameters did not show any difference between groups. The area under the receiver operating characteristic curve for CRM was 1, significantly higher than the area under the receiver operating characteristic for heart rate (0.78), systolic blood pressure (0.67), quick SOFA (0.81), and respiratory rate (0.56). CONCLUSION: Clinical criteria, imaging, and laboratory features used to identify a septic patient are suboptimal. This demonstrates the need for a monitoring device capable of detecting rapidly, constantly, and simply the sum condition of the ill patient. We have shown that CRM was able to distinguish between severe septic and nonseptic patients early in the course of hospitalization and was significantly more sensitive than the conventional diagnostic tools. Such capability to assess the septic patients or even to triage these patients will surely aid treatment of sepsis. LEVEL OF EVIDENCE: Care management, level II.


Assuntos
Artérias/fisiologia , Hemodinâmica , Fotopletismografia , Sepse/diagnóstico , Adulto , Idoso , Algoritmos , Proteína C-Reativa/análise , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Escores de Disfunção Orgânica , Gravidade do Paciente , Valor Preditivo dos Testes , Estudos Prospectivos , Curva ROC , Sepse/classificação , Sepse/fisiopatologia , Choque Séptico/diagnóstico , Choque Séptico/mortalidade
13.
J Trauma Acute Care Surg ; 89(2S Suppl 2): S146-S152, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32118826

RESUMO

BACKGROUND: Current out-of-hospital protocols to determine hemorrhagic shock in civilian trauma systems rely on standard vital signs with military guidelines relying on heart rate and strength of the radial pulse on palpation, all of which have proven to provide little forewarning for the need to implement early intervention prior to decompensation. We tested the hypothesis that addition of a real-time decision-assist machine-learning algorithm, the compensatory reserve measurement (CRM), used by combat medics could shorten the time required to identify the need for intervention in an unstable patient during a hemorrhage profile as compared with vital signs alone. METHODS: We randomized combat medics from the Army Medical Department Center and School Health Readiness Center of Excellence into three groups: group 1 viewed a display of no simulated hemorrhage and unchanging vital signs as a control (n = 24), group 2 viewed a display of simulated hemorrhage and changing vital signs alone (hemorrhage; n = 31), and group 3 viewed a display of changing vital signs with the addition of the CRM (hemorrhage + CRM; n = 22). Participants were asked to push a computer key when they believed the patient was becoming unstable and needed medical intervention. RESULTS: The average time of 11.0 minutes (95% confidence interval, 8.7-13.3 minutes) required by the hemorrhage + CRM group to identify an unstable patient (i.e., stop the video sequence) was less by more than 40% (p < 0.01) compared with 18.9 minutes (95% confidence interval, 17.2-20.5 minutes) in the hemorrhage group. CONCLUSION: The use of a machine-learning monitoring technology designed to measure the capacity to compensate for central blood volume loss resulted in reduced time required by combat medics to identify impending hemodynamic instability. LEVEL OF EVIDENCE: Diagnostic, level IV.


Assuntos
Diagnóstico Precoce , Hemorragia/diagnóstico , Aprendizado de Máquina , Medicina Militar , Lesões Relacionadas à Guerra/diagnóstico , Algoritmos , Volume Sanguíneo , Humanos , Militares , Sinais Vitais
14.
J Trauma Acute Care Surg ; 89(2S Suppl 2): S161-S168, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32044875

RESUMO

BACKGROUND: Hemorrhage remains the leading cause of death following traumatic injury in both civilian and military settings. Heart rate variability (HRV) and heart rate complexity (HRC) have been proposed as potential "new vital signs" for monitoring trauma patients; however, the added benefit of HRV or HRC for decision support remains unclear. Another new paradigm, the compensatory reserve measurement (CRM), represents the integration of all cardiopulmonary mechanisms responsible for compensation during relative blood loss and was developed to identify current physiologic status by estimating the progression toward hemodynamic decompensation. In the present study, we hypothesized that CRM would provide greater sensitivity and specificity to detect progressive reductions in central circulating blood volume and onset of decompensation as compared with measurements of HRV and HRC. METHODS: Continuous, noninvasive measurements of compensatory reserve and electrocardiogram signals were made on 101 healthy volunteers during lower-body negative pressure (LBNP) to the point of decompensation. Measures of HRV and HRC were taken from electrocardiogram signal data. RESULTS: Compensatory reserve measurement demonstrated a superior sensitivity and specificity (receiver operator characteristic area under the curve [ROC AUC] = 0.93) compared with all HRV measures (ROC AUC ≤ 0.84) and all HRC measures (ROC AUC ≤ 0.86). Sensitivity and specificity values at the ROC optimal thresholds were greater for CRM (sensitivity = 0.84; specificity = 0.84) than HRV (sensitivity, ≤0.78; specificity, ≤0.77), and HRC (sensitivity, ≤0.79; specificity, ≤0.77). With standardized values across all levels of LBNP, CRM had a steeper decline, less variability, and explained a greater proportion of the variation in the data than both HRV and HRC during progressive hypovolemia. CONCLUSION: These findings add to the growing body of literature describing the advantages of CRM for detecting reductions in central blood volume. Most importantly, these results provide further support for the potential use of CRM in the triage and monitoring of patients at highest risk for the onset of shock following blood loss.


Assuntos
Volume Sanguíneo/fisiologia , Frequência Cardíaca/fisiologia , Hemodinâmica , Hemorragia/fisiopatologia , Hipovolemia/diagnóstico , Choque/diagnóstico , Adulto , Área Sob a Curva , Pressão Arterial , Eletrocardiografia , Feminino , Voluntários Saudáveis , Hemorragia/complicações , Humanos , Hipovolemia/etiologia , Hipovolemia/fisiopatologia , Pressão Negativa da Região Corporal Inferior , Aprendizado de Máquina , Masculino , Curva ROC , Sensibilidade e Especificidade , Choque/etiologia
15.
Shock ; 53(3): 327-334, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32045396

RESUMO

Hemorrhagic shock can be mitigated by timely and accurate resuscitation designed to restore adequate delivery of oxygen (DO2) by increasing cardiac output (CO). However, standard care of using systolic blood pressure (SBP) as a guide for resuscitation may be ineffective and can potentially be associated with increased morbidity. We have developed a novel vital sign called the compensatory reserve measurement (CRM) generated from analysis of arterial pulse waveform feature changes that has been validated in experimental and clinical models of hemorrhage. We tested the hypothesis that thresholds of DO2 could be accurately defined by CRM, a noninvasive clinical tool, while avoiding over-resuscitation during whole blood resuscitation following a 25% hemorrhage in nonhuman primates. To accomplish this, adult male baboons (n = 12) were exposed to a progressive controlled hemorrhage while sedated that resulted in an average (±â€ŠSEM) maximal reduction of 508 ±â€Š18 mL of their estimated circulating blood volume of 2,130 ±â€Š60 mL based on body weight. CRM increased from 6 ±â€Š0.01% at the end of hemorrhage to 70 ±â€Š0.02% at the end of resuscitation. By linear regression, CRM values of 6% (end of hemorrhage), 30%, 60%, and 70% (end of resuscitation) corresponded to calculated DO2 values of 5.9 ±â€Š0.34, 7.5 ±â€Š0.87, 9.3 ±â€Š0.76, and 11.6 ±â€Š1.3 mL O2·kg·min during resuscitation. As such, return of CRM to ∼65% during resuscitation required only ∼400 mL to restore SBP to 128 ±â€Š6 mmHg, whereas total blood volume replacement resulted in over-resuscitation as indicated by a SBP of 140 ±â€Š7 mmHg compared with an average baseline value of 125 ±â€Š5 mmHg. Consistent with our hypothesis, thresholds of calculated DO2 were associated with specific CRM values. A target resuscitation CRM value of ∼65% minimized the requirement for whole blood while avoiding over-resuscitation. Furthermore, 0% CRM provided a noninvasive metric for determining critical DO2 at approximately 5.3 mL O2·kg·min.


Assuntos
Transfusão de Sangue , Consumo de Oxigênio/fisiologia , Ressuscitação , Choque Hemorrágico/metabolismo , Choque Hemorrágico/terapia , Animais , Pressão Sanguínea , Volume Sanguíneo , Modelos Animais de Doenças , Masculino , Papio
16.
J Trauma Acute Care Surg ; 89(2S Suppl 2): S169-S174, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-31972755

RESUMO

BACKGROUND: Compensatory reserve measurement (CRM) is a novel noninvasive monitoring technology designed to assess physiologic reserve using feature interrogation of arterial pulse waveforms. This study was conducted to validate clinically relevant CRM values with a simplified color-coded dashboard view. METHODS: We performed a prospective observational study of 300 injured patients admitted to a level I trauma center. Compensatory reserve measurement was recorded upon emergency department admission. Data collected to complement the analysis included patient demographics, vital signs, lifesaving interventions, Injury Severity Score (ISS), and outcomes. Threshold values of CRM were analyzed for predictive capability of hemorrhage. RESULTS: A total of 285 patients met the inclusion criteria. Mean age of the population was 47 years, and 67% were male. Hemorrhage was present in 32 (11%), and lifesaving intervention was performed in 40 (14%) patients. Transfusion of packed red blood cells was administered in 33 (11.6%) patients, and 21 (7.4%) were taken to the operating room for surgical or endovascular control of hemorrhage. Statistical analyses were performed to identify optimal threshold values for three zones of CRM to predict hemorrhage. Optimal levels for red, yellow, and green areas of the dashboard view were stratified as follows: red if CRM was less than 30%, yellow if CRM was 30% to 59%, and green if CRM was 60% or greater. Odds of hemorrhage increased by 12-fold (odds ratio, 12.2; 95% confidence interval, 3.8-38.9) with CRM less than 30% (red) and 6.5-fold (odds ratio, 6.5; 95% confidence interval, 2.7-15.9) with CRM of equal to 30% to 59% (yellow) when compared with patients with CRM of 60% or greater. The area under the receiver operating characteristic curve for three-zone CRM was similar to that of continuous CRM (0.77 vs. 0.79) but further increased the ability to predict hemorrhage after adjusting for ISS (area under the receiver operating characteristic curve, 0.87). CONCLUSION: A three-zone CRM could be a potentially useful predictor of hemorrhage in trauma patients with added capabilities of continuous monitoring and a real-time ISS assessment. These data substantiate easily interpretable threshold dashboard values for triage with potential to improve injury outcomes. LEVEL OF EVIDENCE: Diagnostic, level II.


Assuntos
Volume Sanguíneo , Apresentação de Dados , Hemodinâmica , Hemorragia/diagnóstico , Aprendizado de Máquina , Choque/diagnóstico , Adulto , Transfusão de Sangue , Feminino , Hemorragia/complicações , Hemorragia/fisiopatologia , Hemorragia/terapia , Humanos , Escala de Gravidade do Ferimento , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Curva ROC , Fatores de Risco , Sensibilidade e Especificidade , Choque/etiologia , Interface Usuário-Computador , Sinais Vitais
17.
NPJ Microgravity ; 5: 29, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31815179

RESUMO

The concept of prolonged field care (PFC), or medical care applied beyond doctrinal planning timelines, is the top priority capability gap across the US Army. PFC is the idea that combat medics must be prepared to provide medical care to serious casualties in the field without the support of robust medical infrastructure or resources in the event of delayed medical evacuation. With limited resources, significant distances to travel before definitive care, and an inability to evacuate in a timely fashion, medical care during exploration spaceflight constitutes the ultimate example PFC. One of the main capability gaps for PFC in both military and spaceflight settings is the need for technologies for individualized monitoring of a patient's physiological status. A monitoring capability known as the compensatory reserve measurement (CRM) meets such a requirement. CRM is a small, portable, wearable technology that uses a machine learning and feature extraction-based algorithm to assess real-time changes in hundreds of specific features of arterial waveforms. Future development and advancement of CRM still faces engineering challenges to develop ruggedized wearable sensors that can measure waveforms for determining CRM from multiple sites on the body and account for less than optimal conditions (sweat, water, dirt, blood, movement, etc.). We show here the utility of a military wearable technology, CRM, which can be translated to space exploration.

18.
Aerosp Med Hum Perform ; 90(12): 1009-1015, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31747997

RESUMO

BACKGROUND: Portable noninvasive Heart Rate Complexity (HRC) and Compensatory Reserve Measurement (CRM) monitors have been developed to triage supine combat casualties. Neither monitor has been tested in upright individuals during physical exercise. This study tests the hypothesis that exercise evokes proportional changes in HRC and CRM.METHODS: Two instruments monitored volunteers (9 civilian and 11 soldiers) from the Army Trauma Training Department (ATTD) before, during, and following physical exercise. One recorded heart rate (HR, bpm), cardiac output (CO, L · min-1), heart rate variability (HRV, root mean square of successive differences, ms), and HRC (Sample Entropy, unitless). The other recorded HR, pulse oximetry (Spo2, %), and CRM (%).RESULTS: Baseline HR, CO, HRV, HRC, and CRM averaged 72 ± 1 bpm, 5.6 ± 1.2 L · min-1, 48 ± 24 ms, 1.9 ± 0.5, and 85 ± 10% in seated individuals. Exercise evoked peak HR and CO at > 200% of baseline, while HRC and CRM were simultaneously decreased to minimums that were ≤ 50% of baseline (all P < 0.001). HRV changes were variable and unreliable. Spo2 remained consistently above 95%. During a 60 min recovery, HR and CRM returned to baseline on parallel tracks (t1/2=11 ± 8 and 18 ± 14 min), whereas HRC recovery was slower than either CRM or HR (t1/2=40 ± 18 min, both P < 0.05).DISCUSSION: Exercise evoked qualitatively similar changes in CRM and HRC. CRM recovered incrementally faster than HRC, suggesting that vasodilation, muscle pump, and respiration compensate faster than cardiac autonomic control in young, healthy volunteers. Both HRC and CRM appear to provide reliable, objective, and noninvasive metrics of human performance in upright exercising individuals.Mulder MB, Eidelson SA, Buzzelli MD, Gross KR, Batchinsky AI, Convertino VA, Schulman CI, Namias N, Proctor KG. Exercise-induced changes in compensatory reserve and heart rate complexity. Aerosp Med Hum Perform. 2019; 90(12):1009-1015.


Assuntos
Exercício Físico/fisiologia , Frequência Cardíaca/fisiologia , Adulto , Eletrocardiografia , Feminino , Hemostasia , Humanos , Masculino , Oximetria , Oxigênio/sangue , Estudos Prospectivos , Adulto Jovem
19.
J Appl Physiol (1985) ; 127(5): 1187-1196, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31225967

RESUMO

The objective of this minireview is to describe the physiology and potential clinical benefits derived from inspiration. Recent animal and clinical studies demonstrate that one of the body's natural mechanisms associated with inspiration is to harness the respiratory pump to enhance circulation to vital organs. There is evidence that large reductions in intrathoracic pressure (>20 cmH2O) caused by some inspiration maneuvers (e.g., Mueller maneuver) or pathophysiology (e.g., heart failure, chronic obstructive lung disease) can result in adverse hemodynamic effects. However, the respiratory pump can improve cardiovascular functions when a "sweet spot" for generation of negative intrathoracic pressure during inspiration can be maintained at or less than 10 cmH2O below normal inspiration. These beneficial physiological effects include greater cardiac filling and output, lower intracranial pressure, cardiac baroreflex resetting, greater cerebral blood flow oscillatory patterns, increased vascular pressure gradients, and promoting sustained feedback between sympathetic nerve activity and arterial pressure. In addition to promoting gas exchange, data obtained from numerous animal and human experiments have provided new insights into "the other side of breathing": the modulation of circulation by reduced intrathoracic pressure generated during inspiration. The translation of these physiological relationships form the basis for the development and application of technologies designed to optimize the intrathoracic pump for treatment of clinical conditions associated with hypovolemia including cardiac arrest, orthostatic hypotension, hemorrhagic shock, and traumatic brain injury. Harnessing these fundamental mechanisms that control cardiopulmonary physiology provides opportunities to use inspiration as a potential tool to help treat significant and often life-threatening circulatory disorders.


Assuntos
Resistência das Vias Respiratórias/fisiologia , Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Inalação/fisiologia , Respiração , Animais , Parada Cardíaca/diagnóstico , Parada Cardíaca/fisiopatologia , Hemodinâmica/fisiologia , Humanos , Choque Hemorrágico/diagnóstico , Choque Hemorrágico/fisiopatologia
20.
Exp Biol Med (Maywood) ; 244(8): 690-701, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31042073

RESUMO

IMPACT STATEMENT: Disturbance of normal homeostasis occurs when oxygen delivery and energy stores to the body's tissues fail to meet the energy requirement of cells. The work submitted in this review is important because it advances the understanding of inadequate oxygen delivery as it relates to early diagnosis and treatment of circulatory shock and its relationship to disturbance of normal functioning of cellular metabolism in life-threatening conditions of hemorrhage. We explored data from the clinical and exercise literature to construct for the first time a conceptual framework for defining the limitation of inadequate delivery of oxygen by comparing the physiology of hemorrhagic shock caused by severe blood loss to maximal oxygen uptake induced by intense physical exercise. We also provide a translational framework in which understanding the fundamental relationship between the body's reserve to compensate for conditions of inadequate oxygen delivery as a limiting factor to V˙ O2max helps to re-evaluate paradigms of triage for improved monitoring of accurate resuscitation in patients suffering from hemorrhagic shock.


Assuntos
Adaptação Fisiológica/fisiologia , Hipóxia Celular , Hipovolemia/fisiopatologia , Consumo de Oxigênio , Oxigênio/metabolismo , Esforço Físico/fisiologia , Choque Hemorrágico/fisiopatologia , Equilíbrio Ácido-Base/fisiologia , Aerobiose , Animais , Sistema Nervoso Autônomo/fisiopatologia , Débito Cardíaco , Metabolismo Energético , Exsanguinação/fisiopatologia , Glicólise , Hemoglobinas/metabolismo , Homeostase , Humanos , Lactatos/metabolismo , Modelos Cardiovasculares , Mioglobina/metabolismo , Ventilação Pulmonar/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...