The must-read acute care medicine articles from 2021

Patients with hypotension

• Patients should be screened for high risk for hemodynamic collapse prior to administration of induction medications and intubation by assessing the stroke index. A stroke index greater than 0.7 predicts a high risk. These patients should receive hemodynamic optimization (for example, intravenous fluids, administration of vasopressors) whenever possible, prior to administration of induction medications and intubation.
• Vasopressor infusions are preferable to bolus-dosed vasopressors. However, if vasopressor infusions are not possible, bolus-dosed vasopressors should be available and used to maintain systemic pressure during and after the intubation until an infusion can be started. When bolus-dosed vasopressors are used, diluted epinephrine should be considered as the vasopressor of choice in patients with depressed myocardial function.

Patients with right ventricular (RV) dysfunction

• Patients should be screened for significant RV dysfunction prior to intubation because of their high risk for hemodynamic decompensation with positive pressure ventilation.
• RV dysfunction may sometimes worsen with fluid administration. Fluid-intolerant patients may instead need RV afterload reduction with inhaled or intravenous pulmonary vasodilators.
• Patients with RV failure–induced shock should be considered for preintubation extracorporeal membrane oxygenation if available.
• Patients with RV volume overload should receive diuresis prior to intubation.
• Ventilator settings should aim to avoid hypercapnia, maintain low airway pressures, and use a higher PEEP to avoid atelectasis.

Patients with severe metabolic acidosis

• Patients with severe metabolic acidosis are at high risk for decompensation after intubation because of volume depletion and inadequate alveolar ventilation, resulting in profound acidosis.
• Patients with high minute ventilation prior to intubation should be considered for awake intubation to maintain spontaneous respirations. Otherwise, consider a spontaneous breathing mode after intubation with a high minute ventilation (that is, use a higher-than-normal respiratory rate on the ventilator in order to reproduce the preintubation minute ventilation). Apnea time should be minimized in order to minimize worsening acidosis.
• Preintubation bicarbonate boluses to prevent worsening acidosis are controversial and lack data showing any benefit.

Neurologically injured patients

• Eucapnia and normoxia should be maintained before, during, and after intubation to maintain stable cerebral blood flow.
• Hemodynamically neutral induction agents should be used.
• Patients should be positioned with the head of bed elevated to 30° upright when possible.
• Limit PEEP post intubation in order to promote venous drainage.

Evidence update for the treatment of anaphylaxis

The treatment of anaphylaxis is considered bread and butter in emergency and acute care medicine, but a great deal of what we have learned over the years is not well supported by the literature. In an article published in Resuscitation, the Anaphylaxis Working Group of the Resuscitation Council of the United Kingdom performed an evidence review regarding the emergency treatment of anaphylaxis.

A summary of key points includes:

• Anaphylaxis is defined as a systemic hypersensitivity reaction, usually rapid in onset, with potentially life-threatening compromise in airway, breathing, and/or circulation.
• The most important treatment is epinephrine (EPI), with an initial recommended dose in adults of 0.5 mg administered via the intramuscular (IM) route. Up to 10% of patients have a suboptimal response to one dose, but 98% will respond by the third dose; therefore, these authors recommend repeating the IM EPI every 5 minutes, if needed, up to three doses. There is no evidence to support any alternative or additional vasopressors, and so they should only be used if EPI is ineffective. Intravenous EPI is not recommended initially except in the perioperative setting where close monitoring can be performed. If intravenous EPI is used, the authors recommend an intravenous infusion rather than bolus dosing.
• Intravenous fluid bolus dosing is recommended in the majority of cases of anaphylaxis, regardless of presence or absence of hemodynamic compromise, because of the profound reduction in venous tone and third-spacing that typically occurs.
• Antihistamines are not recommended in early treatment. They are only effective for reversing skin manifestations of anaphylaxis (which EPI treats as well), and the sedation they produce can confound the proper ongoing evaluation of the patient. Furthermore, the use of antihistamines early in the treatment of anaphylaxis has been found to produce delays in proper use of EPI.
• Steroids are not recommended in early treatment. They help only with the late phase of inflammatory response, but despite that, there is no good evidence that they decrease the biphasic response of anaphylaxis. There is some emerging evidence that the use of steroids may actually be associated with increased morbidity even after correcting for anaphylaxis severity. The authors recommended the use of steroids in anaphylaxis only for patients with poorly controlled asthma and possibly for patients with refractory anaphylaxis. Inhaled beta-agonists are recommended in anaphylaxis only for patients with lower respiratory tract symptoms caused by anaphylaxis, but warned that the inhaled beta-agonists should not delay proper use of EPI.
• The optimal observation period before discharge for stable patients is unknown. The authors noted the recommendations of the Joint Task Force on Practice Parameters of the American Academy of Allergy, Asthma, & Immunology and the American College of Allergy, Asthma, and Immunology: Biphasic reactions were more common in patients with severe initial symptoms – for example, those requiring more than one dose of EPI; therefore, these patients are recommended to have “extended observation.” Lower-risk patients with resolved symptoms of anaphylaxis can be observed for 1 hour, which would capture 95% of biphasic reactions in this group of patients.

Summary and other honorable mentions

There you have it. My two favorite practice-changing (non–COVID-19) articles of 2021. Not surprisingly, both articles deal largely with airway and hemodynamic concerns – the ABC’s of emergency medicine. Although these bulleted pearls provide key points from these two articles, the full discussions of those key points in the articles would provide a great deal more education than I can provide in this brief write-up, and so I strongly encourage everyone to read the full articles.

I also encourage readers to peruse the following “honorable mention” articles: Stiell and colleagues published a “Best Practices Checklist” on behalf of the Canadian Association of Emergency Physicians pertaining to the management of acute atrial fibrillation and atrial flutter; and on behalf of the American Heart Association (in collaboration with several other major organizations), Gulati and colleagues published the 2021 Guideline for the Evaluation and Diagnosis of Chest Pain. Both publications show us how we should strive to manage atrial fibrillation and chest pain, respectively, in the emergency department for years to come.

Amal Mattu, MD, is a professor, vice chair of education, and codirector of the emergency cardiology fellowship in the department of emergency medicine at the University of Maryland, Baltimore.

A version of this article first appeared on Medscape.com.