A Guide to the Use of Vasopressors and Inotropes for Patients in Shock.

Shock is a life-threatening circulatory failure that results in inadequate tissue perfusion and oxygenation. Vasopressors and inotropes are vasoactive medications that are vital in increasing systemic vascular resistance and cardiac contractility, respectively, in patients presenting with shock. To be well versed in using these agents is an important skill to have in the critical care setting where patients can frequently exhibit symptoms of shock. In this review, we will discuss the pathophysiological mechanisms of shock and evaluate the current evidence behind the management of shock with an emphasis on vasopressors and inotropes.

So You Want to Do Trauma Research? A Practical Guide to Creating a Research Program at Your Home Institution.

BACKGROUND: There are 3 pillars upon which the foundation of a teaching program in health care is founded: research, education, and clinical care. However, in a busy academic trauma practice, the unfortunate reality is that research is often a low priority in the frenzy of mandates for clinical productivity. OBJECTIVE: The purpose of this report is to advise hospitals on how to create a modest trauma research program that supports research interests without significantly impacting the overall clinical productivity of the department. METHODS: Relevant literature related to the development of an academic trauma research department was reviewed. Relevant articles were then compared to this manuscript to assess the novelty of the topic. RESULTS: There are 4 essential components of a trauma research program: (1) a zealot, (2) institutional commitment and support, (3) a statistician, and (4) registry data access. CONCLUSION: The creation of a trauma research program may seem like a herculean effort, but this work is necessary for institutions hoping to achieve status as a Level I/II trauma center. Following the steps outlined in this report, trauma providers can create a robust research program at their institution without sacrificing clinical productivity.

Brain Death/Death by Neurologic Criteria: What You Need to Know.

ABSTRACT: Since the beginning of time, man has been intrigued with the question of when a person is considered dead. Traditionally, death has been considered the cessation of all cardiorespiratory function. At the end of the last century a new definition was introduced into the lexicon surrounding death in addition to cessation of cardiac and respiratory function: Brain Death/Death by Neurologic Criteria (BD/DNC). There are medical, legal, ethical, and even theological controversies that surround this diagnosis. In addition, there is no small amount of confusion among medical practitioners regarding the diagnosis of BD/DNC. For families enduring the devastating development of BD/DNC in their loved one, it is the duty of the principal caregiver to provide a transparent presentation of the clinical situation and clear definitive explanation of what constitutes BD/DNC. In this report, we present a historical outline of the development of BD/DNC as a clinical entity, specifically how one goes about making a determination of BD/DNC, what steps are taken once a diagnosis of BD/DNC is made, a brief discussion of some of the ethical/moral issues surrounding this diagnosis, and finally the caregiver approach to the family of a patient who had been declared with BD/DNC. It is our humble hope that with a greater understanding of the myriad of complicated issues surrounding the diagnosis of BD/DNC that the bedside caregiver can provide needed closure for both the patient and the family enduring this critical time in their life.

The State of the Union: Trauma System Development in the United States.

Injury is both a national and international epidemic that affects people of all age, race, religion, and socioeconomic class. Injury was the fourth leading cause of death in the United States (U.S.) in 2021 and results in an incalculable emotional and financial burden on our society. Despite this, when prevention fails, trauma centers allow communities to prepare to care for the traumatically injured patient. Using lessons learned from the military, trauma care has grown more sophisticated in the last 50 years. In 1966, the first civilian trauma center was established, bringing management of injury into the new age. Now, the American College of Surgeons recognizes 4 levels of trauma centers (I-IV), with select states recognizing Level V trauma centers. The introduction of trauma centers in the U.S. has been proven to reduce morbidity and mortality for the injured patient. However, despite the proven benefits of trauma centers, the U.S. lacks a single, unified, trauma system and instead operates within a "system of systems" creating vast disparities in the level of care that can be received, especially in rural and economically disadvantaged areas. In this review we present the history of trauma system development in the U.S, define the different levels of trauma centers, present evidence that trauma systems and trauma centers improve outcomes, outline the current state of trauma system development in the U.S, and briefly mention some of the current challenges and opportunities in trauma system development in the U.S. today.

American Trauma Care: A System of Systems.

OBJECTIVE: The benefits of organized trauma systems have been well-documented during 50 years of trauma system development in the United States. Unfortunately, despite this evidence, trauma system development has occurred only sporadically in the 50 states. METHODS: The relevant literature related to trauma system design and development was reviewed based on relevance to the study. Information from these sources was summarized into a SWOT (strengths, weaknesses, opportunities, and threats) analysis. RESULTS: Strengths discovered were leadership brought forth by the American College of Surgeons Committee on Trauma and meaningful change generated from The National Academy of Sciences, Engineering, and Medicine report addressing the fractionation of the nation's trauma systems, whereas weaknesses included patient outcome disparities due to the lack of a national governing authority, undertriage, underresourced rural trauma, and underfunded trauma research. Opportunities included the creation of level IV trauma centers; telemedicine; the development of rural trauma management courses; air medical transport to bring high-intensity care to the patient, particularly in rural areas; trauma research; and trauma prevention through outreach and educational programs. The following threats were determined: mass casualty incidents, motor vehicle collisions because of the high rate of motor vehicle collision deaths in the United States relative to other developed countries, and underfunded trauma systems. CONCLUSION: Much work remains to be done in the development of an American trauma system. Recommendations include implementation of trauma care governance at the federal level; national oversight and support of emergency medical services systems, particularly in rural areas with strict reporting processes for emergency medical services programs; national organization of our mass casualty response; increased federal and state funding allocated to trauma centers; a consistent model for trauma system development; and trauma research.

American Association for the Surgery of Trauma/American College of Surgeons Committee on Trauma clinical protocol for management of acute respiratory distress syndrome and severe hypoxemia.

LEVEL OF EVIDENCE: Therapeutic/Care Management: Level V.

Surgical Science and the Evolution of Critical Care Medicine.

Surgical science has driven innovation and inquiry across adult and pediatric disciplines that provide critical care regardless of location. Surgically originated but broadly applicable knowledge has been globally shared within the pages Critical Care Medicine over the last 50 years.

Paradoxical response to chest wall loading predicts a favorable mechanical response to reduction in tidal volume or PEEP.

BACKGROUND: Chest wall loading has been shown to paradoxically improve respiratory system compliance (CRS) in patients with moderate to severe acute respiratory distress syndrome (ARDS). The most likely, albeit unconfirmed, mechanism is relief of end-tidal overdistension in 'baby lungs' of low-capacity. The purpose of this study was to define how small changes of tidal volume (VT) and positive end-expiratory pressure (PEEP) affect CRS (and its associated airway pressures) in patients with ARDS who demonstrate a paradoxical response to chest wall loading. We hypothesized that small reductions of VT or PEEP would alleviate overdistension and favorably affect CRS and conversely, that small increases of VT or PEEP would worsen CRS. METHODS: Prospective, multi-center physiologic study of seventeen patients with moderate to severe ARDS who demonstrated paradoxical responses to chest wall loading. All patients received mechanical ventilation in volume control mode and were passively ventilated. Airway pressures were measured before and after decreasing/increasing VT by 1 ml/kg predicted body weight and decreasing/increasing PEEP by 2.5 cmH2O. RESULTS: Decreasing either VT or PEEP improved CRS in all patients. Driving pressure (DP) decreased by a mean of 4.9 cmH2O (supine) and by 4.3 cmH2O (prone) after decreasing VT, and by a mean of 2.9 cmH2O (supine) and 2.2 cmH2O (prone) after decreasing PEEP. CRS increased by a mean of 3.1 ml/cmH2O (supine) and by 2.5 ml/cmH2O (prone) after decreasing VT. CRS increased by a mean of 5.2 ml/cmH2O (supine) and 3.6 ml/cmH2O (prone) after decreasing PEEP (P < 0.01 for all). Small increments of either VT or PEEP worsened CRS in the majority of patients. CONCLUSION: Patients with a paradoxical response to chest wall loading demonstrate uniform improvement in both DP and CRS following a reduction in either VT or PEEP, findings in keeping with prior evidence suggesting its presence is a sign of end-tidal overdistension. The presence of 'paradox' should prompt re-evaluation of modifiable determinants of end-tidal overdistension, including VT, PEEP, and body position.

Paradoxical Positioning: Does "Head Up" Always Improve Mechanics and Lung Protection?

OBJECTIVES: Head-elevated body positioning, a default clinical practice, predictably increases end-expiratory transpulmonary pressure and aerated lung volume. In acute respiratory distress syndrome (ARDS), however, the net effect of such vertical inclination on tidal mechanics depends upon whether lung recruitment or overdistension predominates. We hypothesized that in moderate to severe ARDS, bed inclination toward vertical unloads the chest wall but adversely affects overall respiratory system compliance (C rs ). DESIGN: Prospective physiologic study. SETTING: Two medical ICUs in the United States. PATIENTS: Seventeen patients with ARDS, predominantly moderate to severe. INTERVENTION: Patients were ventilated passively by volume control. We measured airway pressures at baseline (noninclined) and following bed inclination toward vertical by an additional 15°. At baseline and following inclination, we manually loaded the chest wall to determine if C rs increased or paradoxically declined, suggestive of end-tidal overdistension. MEASUREMENTS AND MAIN RESULTS: Inclination resulted in a higher plateau pressure (supineΔ: 2.8 ± 3.3 cm H 2 O [ p = 0.01]; proneΔ: 3.3 ± 2.5 cm H 2 O [ p = 0.004]), higher driving pressure (supineΔ: 2.9 ± 3.3 cm H 2 O [ p = 0.01]; proneΔ: 3.3 ± 2.8 cm H 2 O [ p = 0.007]), and lower C rs (supine Δ: 3.4 ± 3.7 mL/cm H 2 O [ p = 0.01]; proneΔ: 3.1 ± 3.2 mL/cm H 2 O [ p = 0.02]). Following inclination, manual loading of the chest wall restored C rs and driving pressure to baseline (preinclination) values. CONCLUSIONS: In advanced ARDS, bed inclination toward vertical adversely affects C rs and therefore affects the numerical values for plateau and driving tidal pressures commonly targeted in lung protective strategies. These changes are fully reversed with manual loading of the chest wall, suggestive of end-tidal overdistension in the upright position. Body inclination should be considered a modifiable determinant of transpulmonary pressure and lung protection, directionally similar to tidal volume and positive end-expiratory pressure.

A Rationale for Safe Ventilation with Inhalation Injury: An Editorial Review.

Lung injury from smoke inhalation manifests as airway and parenchymal damage, at times leading to the acute respiratory distress syndrome. From the beginning of this millennium, the approach to mechanical ventilation in the patient with ARDS was based on reduction of tidal volume to 6 milliliters/kilogram of ideal body weight, maintaining a ceiling of plateau pressure, and titration of driving pressure (plateau pressure minus PEEP). Beyond these broad constraints, there is little specification for the mechanics of ventilator settings, consideration of the metabolic impact of the disease process on the patient, or interaction of patient disease and ventilator settings. Various studies suggest that inhomogeneity of lung injury, which increases the risk of regional lung trauma from mechanical ventilation, may be found in the patient with smoke inhalation. We now appreciate that energy transfer principles may affect optimal ventilator management and come into play in damaged heterogenous lungs. Mechanical ventilation in the patient with inhalation injury should consider various factors. Self-injurious respiratory demand by the patient can be reduced using analgesia and sedation. Dynamic factors beginning with rate management can reduce the incidence of potentially damaging ventilation. Moreover, preclinical study is underway to examine the flow of gas based on the ventilator mode selected, which may also be a factor triggering regional lung injury.

Static and Dynamic Measurements of Compliance and Driving Pressure: A Pilot Study.

RATIONALE: Monitoring tidal cycle mechanics is key to lung protection. For this purpose, compliance and driving pressure of the respiratory system are often measured clinically using the plateau pressure, obtained after imposing an extended end-inspiratory pause, which allows for relaxation of the respiratory system and redistribution of inflation volume (method A). Alternative methods for estimating compliance and driving pressure utilize the measured pressure at the earliest instance of zero flow (method B), the inspiratory slope of the pressure-time tracing during inflation with constant flow (method C), and the expiratory time constant (method D). METHODS: Ten passive mechanically ventilated subjects, at a large tertiary referral center, underwent measurements of compliance and driving pressure using the four different methods. The inspiratory tidal volume, inspiratory to expiratory ratio, and positive end expiratory pressures were then adjusted from baseline and the measurements re-obtained. RESULTS: Method A yielded consistently higher compliance and lower driving pressure calculations compared to methods B and C. Methods B and C most closely approximated one another. Method D did not yield a consistent reliable pattern. CONCLUSION: Static measurements of compliance and driving pressure using the plateau pressure may underestimate the maximum pressure experienced by the most vulnerable lung units during dynamic inflation. Utilizing the pressure at zero flow as a static measurement, or the inspiratory slope as a dynamic measurement, may calculate a truer estimate of the maximum alveolar pressure that generates stress upon compromised lung units.