2022 SCAI SHOCK

Title:
Mixed Shock in the Intensive Care Unit: Importance of Repeated Clinical Evaluation

Introduction:
Cardiogenic shock is frequently seen in the intensive care unit. Often, it coexists or superimposes on existing distributive shock versus other forms of shock. In this case report, we will seek to highlight this spectrum of multi etiology shock.

Clinical Case:
A 71-year-old female presented from home for being unresponsive. On examination in the ED, she was minimally responsive to touch and called but was protecting her airway but appeared tenuous. She had a past medical history of hypertension and chronic obstructive pulmonary disease. Physical examination showed hypotension (51/32 mmHg), tachycardia (105 bpm) and tachypnea (35/min), hypoxemia (SPO2 80%). Her cardiorespiratory exam was normal except for coarse breath sounds bilaterally. She had edema to his bilateral lower extremities and pressure ulcerations. Her laboratory parameters showed an elevated lactate (2.3 mmol/L), acute kidney injury and elevated cardiac biomarkers. Her blood gas showed acute on chronic respiratory acidosis and chest computerized tomographic scan demonstrated emphysema and bilateral pleural effusions. Her electrocardiogram demonstrated atrial fibrillation. Due to her acute on chronic respiratory failure, she was intubated and mechanically ventilated. She was treated with broad-spectrum antimicrobials and vasoactive medications (norepinephrine and vasopressin) for undifferentiated shock of likely septic etiology. Echocardiography demonstrated biventricular dilatation, low LVEF of 20 to 25% and decreased RV systolic function, right ventricular systolic pressure of 43 mmHg and dilated inferior vena cava. She also had severe mitral and tricuspid regurgitation that appeared to be functional. Due to her respiratory failure, right ventricular dilatation and inability to obtain CT pulmonary angiogram, she was empirically started on heparin for suspected pulmonary embolism.

Due to clinical improvement on vasoactive medications, antimicrobial therapy and mechanical ventilation, her right heart catheterization was deferred. When she had and clinical stability, she received an elective left and right heart catheterization that demonstrated elevated biventricular filling pressures (right atrium 20 mmHg, left ventricular end-diastolic pressure 30 mmHg), low cardiac index (1.8 L/min/m2). An intra-aortic balloon pump was placed for cardiac output augmentation. Coronary angiography demonstrated a 99% mid left anterior descending artery occlusion which was treated with percutaneous coronary intervention.

Three days later, she developed hyperthermia, oliguria and leukocytosis concerning for a secondary shock etiology. She underwent a repeat right heart catheterization that demonstrated lower biventricular filling pressures but worsening cardiac index concerning for a distributive shock. Due to ongoing shock, percutaneous left and right ventricular assist devices were placed to assist with combined septic and cardiogenic shock. However, the patient continued to deteriorate with worsening acute kidney injury, acute liver failure and lactic acidosis. Despite broad-spectrum antimicrobials, she developed multiorgan failure and transition to comfort care and subsequently passed.

Discussion:
Cardiogenic shock often presents in the setting of either primary or secondary septic shock and can display mixed behavior. Detailed understanding of hemodynamics at frequent time intervals and use of pulmonary artery catheterization to assist with decision making for pharmacological or mechanical circulatory support is of paramount importance in such patients with mixed shock.