Measuring the compensatory reserve to identify shock

Convertino, Víctor A.; Schiller, Alicia M.

doi:10.1097/ta.0000000000001430

Cited by 27 publications

(48 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The algorithm identifies the most similar waveform in the waveform library with the unknown sample to generate a CRM value. Modified from Convertino et al…”

Section: Mesauring the Crmentioning

confidence: 99%

The compensatory reserve: potential for accurate individualized goal‐directed whole blood resuscitation

Convertino

Koons

2020

Transfusion

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…The algorithm identifies the most similar waveform in the waveform library with the unknown sample to generate a CRM value. Modified from Convertino et al…”

Section: Mesauring the Crmentioning

confidence: 99%

The compensatory reserve: potential for accurate individualized goal‐directed whole blood resuscitation

Convertino

Koons

2020

Transfusion

Self Cite

View full text Add to dashboard Cite

show abstract

“…The capacity for compensation that "protects" against low tissue perfusion during states of compromised DO 2 is known as the compensatory reserve. 10,[63][64][65] A historical challenge has been to develop a capability to measure the integration of compensatory mechanisms, particularly as it relates to DO 2 , rather than their physiological outcomes (e.g. blood pressure, SpO 2 , blood pH).…”

Section: Physiologic Similarities Between Hemorrhagic Shock and _mentioning

confidence: 99%

Physiological comparison of hemorrhagic shock and V˙O₂max: A conceptual framework for defining the limitation of oxygen delivery

Convertino

Lye

Koons

et al. 2019

Exp Biol Med (Maywood)

View full text Add to dashboard Cite

Based on evidence extracted from a cross-sectional review of the literature, we sought to advance a novel conceptual framework that the physiology of hemorrhagic shock from exsanguination and maximal oxygen uptake ([Formula: see text]O2max), induced by physical exercise, shares key common features. As such, this review focuses on the notion that intolerance to inadequate oxygen delivery (DO2) resulting from associated states of hypovolemia appears to be a common physiological link that “connects” hemorrhagic shock to the physiology that limits maximal aerobic capacity. Our approach focuses on the similarities in a complex cascade of cardiopulmonary, metabolic and autonomic compensatory responses during hemorrhage and maximal physical exertion that ultimately function to avoid critical levels of DO2 (DO2crit) and are manifested by elevation in blood lactate levels. We introduce a paradigm of absolute (i.e. hemorrhage) versus relative (i.e. exercise) hypovolemia as a primary physiological factor that contributes to reaching DO2crit, and define the concept of “O2 deficit” to replace the clinical concept of O2 debt. Using the peer-reviewed literature, we provide human data obtained from patients who suffered hemorrhagic shock from severe blood loss and compare it to healthy subjects who performed maximal exercise. We include a novel conceptual framework of the continuum of metabolic relationship between DO2 and [Formula: see text]O2 that is manifested as the final step during both progressive blood loss leading to hemorrhagic shock and at [Formula: see text]O2max. We present evidence to support the contribution of utilizing “O2 extraction reserve” as the initial mechanism for developing an O2 deficit, and the notion of individual variability in compensatory responses. In the absence of reversing inadequate DO2, an increased reliance on O2 extraction reserve, cellular anaerobic glycolysis, and phosphocreatine stores to supplement the energy required by the tissues for normal function will deplete a finite capacity for compensation. In the end, acidity reflected by a blood pH ≤ ∼7.0 leads to disturbance of normal cell functioning of metabolic machinery manifested by irreversible shock in the case of hemorrhage or physical exhaustion when [Formula: see text]O2max is reached. 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 [Formula: see text]O2max helps to re-evaluate paradigms of triage for improved monitoring of accurate resuscitation in patients suffering from hemorrhagic shock.

show abstract

“…CRM represents a new paradigm that measures the sum total of all mechanisms that compensate for relative blood volume deficit to allow for early recognition of physiological compromise earlier than the development of clinical symptoms. 4,11,26,27…”

Section: Hypovolemia and Physiological Compensationmentioning

confidence: 99%

Bridging the gap between military prolonged field care monitoring and exploration spaceflight: the compensatory reserve

et al. 2019

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Measuring the compensatory reserve to identify shock

Cited by 27 publications

References 58 publications

The compensatory reserve: potential for accurate individualized goal‐directed whole blood resuscitation

The compensatory reserve: potential for accurate individualized goal‐directed whole blood resuscitation

Physiological comparison of hemorrhagic shock and V˙O₂max: A conceptual framework for defining the limitation of oxygen delivery

Bridging the gap between military prolonged field care monitoring and exploration spaceflight: the compensatory reserve

Contact Info

Product

Resources

About

Measuring the compensatory reserve to identify shock

Cited by 27 publications

References 58 publications

The compensatory reserve: potential for accurate individualized goal‐directed whole blood resuscitation

The compensatory reserve: potential for accurate individualized goal‐directed whole blood resuscitation

Physiological comparison of hemorrhagic shock and V˙O2max: A conceptual framework for defining the limitation of oxygen delivery

Bridging the gap between military prolonged field care monitoring and exploration spaceflight: the compensatory reserve

Contact Info

Product

Resources

About

Physiological comparison of hemorrhagic shock and V˙O₂max: A conceptual framework for defining the limitation of oxygen delivery