normal PCO2. It should correct with administration of oxygen. Shunting (pulmonary edema or pneumonia) has an elevated A‐a gradient that does not improve with oxygen administration. The patient is young for postoperative MI and has risk factors and a chest x‐ray consistent with COVID‐19 pneumonia, which could also increase his risk of thrombotic events since as an arterial thrombus.Answer: CWeinberger SE, Cockrill BA and Mande J. Principles of Pulmonary Medicine , 5th ed., W.B. Saunders, Philadelphia, PA, (2008).NIH COVID‐19 Treatment Guidelines. Therapeutic management of patients with COVID‐19. www.covid19treatmentguidelines.nih.gov/therapeutic‐management/ (accessed 15 December 20).23 A 63‐year‐old patient with history of hypertension and type 2 diabetes presents with acute respiratory distress syndrome from pneumococcal pneumonia and is being managed by the ICU team for severe ARDS. After appropriate sedation and analgesia, which of the following is NOT an appropriate strategy for management?Low tidal volume ventilation (4–8ml/kg IBW).Prone positioning <6 hours/day.Use of recruitment maneuvers.Higher PEEP levels with plateau pressures <30 cm H2O.Very select use of high‐frequency oscillatory ventilation.Acute respiratory distress syndrome management guidelines target management with low tidal volume ventilation, low inspiratory pressures with plateau pressures <30 cm H20, high PEEP levels are better than low PEEP levels, and prone positioning for at least 12‐hour periods per day with improved mortality. Less than 6 hours of prone position per day would not be recommended as it is too short a time period.Answer: BFan E., Del Sorbo L, Goligher EC, et al. An Official American Thoracic Society/European Society of Intensive Care Medicine/Society of critical care medicine clinical practice guideline: mechanical ventilation in adult patients with acute respiratory distress syndrome. Am J Respir Crit Care Med. 2017; 195 9: 1253–1263. https://www.thoracic.org/statements/resources/cc/ards‐guidelines.pdf.
2 Cardiopulmonary Resuscitation, Oxygen Delivery and Shock
Kevin W. Cahill, MD, Harsh Desai, MD, and Luis Cardenas, DO, PhD
Department of Surgery, Christiana Care Health Care System, Newark, DE, USA
1 A 72‐year‐old woman with a history of Child’s B cirrhosis and supraventricular tachycardia is in the ICU following laparotomy for strangulated ventral hernia. She begins to complain of rapid heartbeat and is noted to be in an irregular, wide‐complex ventricular tachycardia on EKG. She maintains pulse and adequate blood pressure. Which of the following is the best initial therapy to administer?Synchronized cardioversion.Adenosine 6 mg IV.Amiodarone 150 mg IV.Defibrillation.Vagal maneuvers.The 2020 ACLS guidelines differentiate between regular and irregular wide‐complex tachycardia with and without pulse. In this instance, the patient is in an irregular wide‐complex tachycardia, symptomatic, but stable as evidence by pulse and pressure. Given this hemodynamic stability, synchronized cardioversion and defibrillation are not the initial therapies (choices A, D). Adenosine and vagal maneuvers may be effective in regular ventricular tachycardia (choices B, E). Therefore, amiodarone is the best initial medication to administration often followed by infusion (choice C). Individuals with hemodynamically unstable ventricular tachycardia should not initially receive amiodarone. These individuals should be cardioverted. Amiodarone can be used regardless of the individual's underlying heart function and the type of ventricular tachycardia. It can be used in individuals with monomorphic ventricular tachycardia, but is contraindicated in individuals with polymorphic ventricular tachycardia as it is associated with prolonged QT intervals, which will be made worse with anti‐arrhythmic drugs. Amiodarone is categorized as a class III anti‐arrhythmic agent, and prolongs phase 3 of the cardiac action potential. Amiodarone slows conduction rate and prolongs the refractory period of the SA and AV nodes. It also prolongs the refractory periods of the ventricles, bundles of His, and the Purkinje fibers without exhibiting any effects on the conduction rate. Serious side effects include interstitial lung disease and liver dysfunction with elevated liver enzymes.Answer: CLittmann L, Olson EG, Gibbs MA . Initial evaluation and management of wide‐complex tachycardia: a simplified and practical approach. Am J Emerg Med. 2019; 37: 1340–1345.Panchal AR, Bartos JA, Cabanas JG et al. Part 3: Adult basic and advanced cardiac life support: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2020; 142 (suppl 2): S366–S468.
2 Which of the following techniques has not been shown to be effective in airway management during cardiac arrest?Head tilt – chin liftJaw thrustCricoid pressureNasopharyngeal airwayOropharyngeal airwayOf the above maneuvers, cricoid pressure has not been shown to be effective during airway management in cardiopulmonary resuscitation. It may impede ventilation or placement of airway adjuncts such as a supraglottic airway as well as contribute to increased airway trauma. Jaw thrust is preferred in patients with suspected spinal injury. Nasopharyngeal and oropharyngeal airways are particularly useful in cases of facial trauma though care must be taken with possible basilar skull fractures.Answer: CCarauna E, Chevret S, Pirracchio R . Effect of cricoid pressure on laryngeal view during prehospital tracheal intubation: a propensity‐based analysis. Emerg Med J. 2017; 34 (3): 132–137.Panchal AR, Bartos JA, Cabanas JG et al. Part 3: Adult basic and advanced cardiac life support: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2020; 142 (suppl 2): S366–S468.
3 In a patient experiencing PEA arrest, which of the following would not be a likely etiology?HypoglycemiaHypoxiaHypovolemiaHypokalemiaHypocalcemiaPulseless electrical activity is so named due to evidence of cardiac mechanical activity on echocardiogram or rhythm on EKG. The algorithm is similar to the asystole algorithm utilizing compressions and epinephrine. The traditional etiologies are described as “Hs” and “Ts.” The “Hs” include hypoglycemia, hypoxia, hyper/hypokalemia, hypovolemia, acidosis, and hypothermia. Hypocalcemia can present with muscular and neurologic symptoms such as perioral numbness, cramping, fatigue, seizures, and irritability. Hypocalcemia may also be associated with increased risk of arrhythmias, but is not typically considered high on the initial differential of PEA arrest. The “Ts” taught as etiologies include tension pneumothorax, cardiac tamponade, toxins, pulmonary thrombosis, or coronary thrombosis. Evaluation for pneumothorax or tamponade includes rapid bedside physical exam as well as point of care ultrasound for rule out. Ultrasound may also reveal signs of thrombosis with right ventricular enlargement or free‐floating thrombus.Answer: EAndersen LW, Holmberg MJ, Berg KM et al. In hospital cardiac arrest: a review. JAMA. 2019; 321 (12): 1200–1210.Panchal AR, Bartos JA, Cabanas JG et al. Part 3: Adult basic and advanced cardiac life support: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2020; 142 (suppl 2): S366–S468.
4 Which of the following is the minimum chest compression fraction (defined as amount of time spent delivering chest compressions during CPR) shown to be associated with improved survival?0–20%21–40%41–60%61–80%81–100%Optimal outcomes have been demonstrated with minimal pauses between compressions for pulse checks and breaths given during high‐quality CPR. A compression fraction of at least 60% has been shown to be necessary for best outcomes. Animal studies previously conducted have demonstrated decreased coronary and cerebral perfusion when chest compressions are not being conducted resulting in worsened outcomes. Multiple retrospective analyses and cohort studies have resulted in many emergency agencies targeting a compression fraction of between 60 and 80% as a quality metric. This involves delivery of high‐quality compressions of appropriate depth, 2 inches, and rate, at least 100/min.Answer: DChristenson J, Andrusiek D, Everson‐Stewart S et al. Chest compression fraction determines survival in patients with out of hospital ventricular fibrillation. Circulation. 2009; 120: 1241–1247.Panchal AR, Bartos JA, Cabanas JG et al. Part 3: Adult basic and advanced cardiac life support: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2020; 142 (suppl 2): S366–S468.
5 Which of the following
