Managing Shock

Educational Objectives

The goal of this program is to improve the management of shock. After hearing and assimilating this program, the clinician will be better able to:

1. Diagnose contributing conditions and mimics of septic shock.
2. Use ultrasonography to assess fluid responsiveness in patients presenting with symptoms of shock.
3. Implement initiatives for fluid stewardship in patients with shock.

Summary

Recognizing shock: a high index of suspicion is key; consider sepsis if 2 of the 4 systemic inflammatory response syndrome (SIRS) criteria are present; however, SIRS is broader than the sequential organ failure assessment (SOFA) and quick SOFA (qSOFA); currently, the best markers for outcome appear to be the National Early Warning score (NEWS) and NEWS2, which include heart rate, respiratory rate, blood pressure, temperature, oxygen saturation, and mental status; NEWS has been shown to be superior to qSOFA in detecting sepsis and organ dysfunction within the emergency department (ED); SOFA and qSOFA are intended more for the intensive care unit (ICU) setting; NEWS and NEWS2 are intended more for the ED; assess mental status as a marker for reduced perfusion to the brain; assess the pulse and specifically try to identify new-onset atrial fibrillation (AF); the most common dysrhythmia is AF with rapid ventricular response; this is triggered either by the underlying shock state or the management because of administration of vasoactive agent; assess the skin for rash, petechiae, bruising, and color; rule out hemorrhagic shock; look for occult sources of bleeding; perform a rectal examination for melanotic stool or hematochezia; assess for insulin resistance and new-onset diabetes mellitus in the setting of shock and increases in creatinine and international normalized ratio; thrombocytopenia is the least useful marker for severity of illness

Ultrasonography (USG): utilize USG early and often to assess cardiac function, dynamic response to passive leg raises, and fluid sequestration in the pericardial space, pleural space, peritoneal space, or soft tissues; regardless of the etiology of shock (eg, neurogenic, cardiogenic, hemorrhagic), USG can be used to assess dynamic responses to fluid boluses or a simulated fluid bolus by passive leg raise; passive leg raise mimics 500 mL of blood return to the right heart; if blood pressure or pulse pressure variation increases by 10% to 15%, it mimics the stroke index; perform USG to look at stroke volume index as a marker

Vasopressors: in cardiogenic shock associated with return of spontaneous circulation (ROSC), >50% of patients will require vasopressors; for out-of-hospital cardiac arrest with ROSC, prepare norepinephrine (Levophed) and dobutamine to avoid delays in administration of potentially life-sustaining medications; both are inexpensive

Computed tomography (CT): used for septic shock and cardiac arrest without an identifiable source; CT of the chest, abdomen, and pelvis is high yield in finding the etiology, but studies have not demonstrated differences in outcomes

Hypotension: is a red flag warning; shock index is a marker of poor outcomes; utilizing the team and USG is critically important for the resuscitation of patients

Management: for septic shock, hemorrhagic shock, or neurogenic shock, norepinephrine is recommended; for anaphylactic shock, epinephrine is used; fluid boluses alone will not help; there are dangers of fluid in resuscitation; overresuscitation with fluids can create left ventricular (LV) dysfunction; consider other diagnoses besides sepsis; 10% of patients admitted from the ED are discharged with an alternative diagnosis than sepsis because of confirmation bias and therapeutic and diagnostic momentum; if the patient does not respond to resuscitative efforts, broaden the differential diagnosis; when delaying vasopressors at 2 hr in the setting of shock, mortality increases by 5% for every additional hour of delay

Mean arterial pressure (MAP) target: range should be 65 to 70 mm Hg in all cases, with the exception of a target of >75 mm Hg for ROSC after cardiac arrest; 1 study reported no benefit, but 3 small studies showed benefit for higher MAP; in the setting of neurogenic shock, a target MAP of >75 mm Hg is recommended, though the evidence is not strong; the American Association of Neurological Surgeons recommends the higher MAP with the goal of perfusing the penumbra; perfusing the penumbra and preventing the extension of injury has a major effect on outcomes

Medication reactions: assess for drug-drug interactions and drug reactions; check the patient’s medication list; determine what medications the patient has at home, including complementary and over-the-counter medications; hepatic failure can mimic septic shock; check for illicit substances

Infection vs inflammation: macrophage activation syndrome (MAS) is a life-threatening inflammatory disorder; it is not an infection; MAS can be triggered by viral illnesses (eg, COVID-19), systemic juvenile idiopathic arthritis, Still disease, and systemic lupus erythematosus; MAS mimics severe infection; the diagnosis is made with bone marrow biopsy; serum tests are not helpful yet; MAS causes sustained high fevers, pancytopenia, liver dysfunction, and secondary organ injury sustained over days, leading to death

Other differential diagnoses: consider endocrinopathies, including thyroid and adrenal disease; pulmonary hypertension (PHTN) is a silent killer; patients typically present to the ED 5 times before the diagnosis is made; physicians reading echocardiography are trained to focus on the left heart and tend to disregard the right heart; if PHTN is suspected, request an evaluation of the right heart and an estimate of pulmonary arterial pressures when ordering echocardiography; patients present with decreased exercise tolerance and atypical chest pain; the typical patient is a Black woman aged 20 to 40 yr; an acute exacerbation of PHTN is extremely difficult to manage because of the administration of small amounts of fluid boluses and vasopressors; a small amount of dobutamine can be added, and diuretics can be considered; consider cancer treatment, chemotherapy, and immune therapy; patients may not mention immune therapy when asked for medications because they do not consider it a medicine

Early antibiotics: early administration of broad-spectrum antibiotics significantly affects outcomes; delays between ordering antibiotics and their administration can be considerable; there should be verbal communication to the team about the importance of administering the first dose quickly; the timing of a second dose for boarders in the ED is equally important; it is important to identify and control the source; each hour of delay in source control is associated with an increase in 90-day mortality

Fluid resuscitation and fluid tolerance: Douglas et al (2020) — a prospective, multicentered, randomized trial on passive leg raise was done to assess fluid responsiveness; fluid responsiveness was used to determine the need for fluid boluses or vasopressors; fluid balance at 72 hr was significantly lower (by 1.37 L), favoring the intervention group; this difference resulted in less renal replacement therapy (5.1% vs 17.5%) and less mechanical ventilation (17.7% vs 34.1%); the study was insufficiently powered to show mortality benefit

Fluid boluses in sepsis: the current teaching is to administer a fluid bolus if dynamic measures predict the patient will respond to a fluid bolus with increase in stroke volume index, pulse pressure variation, or improvement in blood pressure; the speaker questions the utility of this practice; intravenous (IV) fluids are temporizing and last <60 min in the vascular space; delay in instituting vasopressors increases mortality

Venous excess ultrasound (VExUS) score: venous congestion is assessed, most notably in the liver, reflective of the gut, based on the portal vein and in the kidney; the emphasis is on splanchnic congestion; the 4 sites assessed in VExUS are the inferior vena cava and hepatic, portal, and renal veins; doppler flow is assessed in the hepatic, portal, and renal veins; score is 0 to 3; the concept is that, if VExUS reveals severe hepatic, portal, and renal congestion in a patient who is fluid responsive based on dynamic measures, administration of a fluid bolus will be harmful; a single center study investigating cardiorenal syndrome reported a significant association between changes in the VExUS score and fluid balance; another study compared VExUS with the gold standard (pulmonary artery catheterization) and reported similar outcomes

Fluid creep: fluids administered by emergency medical services (EMS) before arrival at the ED are not reconciled when determining the initial fluid bolus, and fluids administered in the ED are not reconciled with the ICU

Manifestation of excessive fluid: the glycocalyx, which holds the capillaries together and maintains fluid within the space, is damaged by excess fluid, creating endothelial injury; this manifests as confusion and myocardial depression; evidence demonstrates impaired contractility, prolonged mechanical ventilation, complications with acute respiratory distress syndrome, hepatic congestion, increased cholestasis in the gut causing ileus and malabsorption, renal interstitial edema, and salt retention; a fluid bolus with congestion in the kidney causes further harm and increases the likelihood of dialysis; fluid creep results in intubation in 50% more patients, 67% more requiring renal replacement therapy, twice the time on vasopressors, and prolonged ICU stay by ≈3 days

Fluid stewardship: should be increased; oral fluids are preferred over IV fluids; consider fluids in boluses, drips, and antibiotic administration; reconcile fluids during handoffs between EMS, the ED, and the ICU; educate teams on fluid stewardship

Extremes of heat: sepsis and meningoencephalitis cannot be excluded in heat-related illness; patients often present with low platelets and are vasopressor-dependent; serotonin syndrome, neuroleptic malignant syndrome, MAS, drug-drug interactions, illicit drug use, and complementary medicines combined with exposure to heat can result in poor outcomes; predictors of poor outcomes include elevated heat-related illness, increased creatinine phosphokinase, profound metabolic acidosis, multiorgan failure, vasopressor dependence, and elevated liver enzymes

Salvage therapy: assess electrolytes, specifically hypoglycemia; low calcium can be attributable to persistent hypotension; severe metabolic acidosis can be related to lactic acidemia; the goal in this case is renal replacement therapy; consider adrenal insufficiency; patients should receive 200 to 300 mg of hydrocortisone as a drip over 24 hr; consider screening for hypothyroidism; consider extracorporeal membrane oxygenation or a ventricular assist device to address LV dysfunction if the etiology is reversible; consider adding dobutamine for hypokinesis; a randomized controlled trial initiated methylene blue within 24 hr of norepinephrine for septic shock and reported decrease in vasopressor requirement, reduced ICU stay and overall hospitalization, and no change in mortality; be cautious in patients with glucose-6-phosphorylase deficiency and those on serotonergic agents

Readings

Beck V, Chateau D, Bryson GL, et al. Timing of vasopressor initiation and mortality in septic shock: a cohort study. Crit Care. 2014;18(3):R97. Published 2014 May 12. doi:10.1186/cc13868; Crayne CB, Albeituni S, Nichols KE, et al. The immunology of macrophage activation syndrome. Front Immunol. 2019;10:119. Published 2019 Feb 1. doi:10.3389/fimmu.2019.00119; Douglas IS, Alapat PM, Corl KA, et al. Fluid response evaluation in sepsis hypotension and shock: a randomized clinical trial. Chest. 2020;158(4):1431-1445. doi:10.1016/j.chest.2020.04.025; Hawkins WA, Smith SE, Newsome AS, et al. Fluid stewardship during critical illness: A call to action. J Pharm Pract. 2020;33(6):863-873. doi:10.1177/0897190019853979; Hawryluk G, Whetstone W, Saigal R, et al. Mean arterial blood pressure correlates with neurological recovery after human spinal cord injury: analysis of high frequency physiologic data. J Neurotrauma. 2015;32(24):1958-1967. doi:10.1089/neu.2014.3778; Ibarra-Estrada M, Kattan E, Aguilera-González P, et al. Early adjunctive methylene blue in patients with septic shock: a randomized controlled trial. Crit Care. 2023;27(1):110. Published 2023 Mar 13. doi:10.1186/s13054-023-04397-7; Niemelä V, Siddiqui F, Ameloot K, et al. Higher versus lower blood pressure targets after cardiac arrest: Systematic review with individual patient data meta-analysis. Resuscitation. 2023;189:109862. doi:10.1016/j.resuscitation.2023.109862; Welch J, Dean J, Hartin J. Using NEWS2: an essential component of reliable clinical assessment. Clin Med (Lond). 2022;22(6):509-513. doi:10.7861/clinmed.2022-0435.

Disclosures

For this program, members of the faculty and the planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. DeBlieux was recorded at the Critical Points in Emergency Critical Care, held October 22-24, 2024, in Atlanta, GA, and presented by Well Assembled Meetings. For more information about upcoming CME activities from this presenter, please visit WellAssembled.com/events. Audio Digest thanks the speakers and Well Assembled Meetings for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 1.50 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 1.50 CE contact hours.

Lecture ID:

EM420702

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.