Critical Care · Year 4 · from Critical Care
Case 1: Septic Shock - Vasopressor Escalation
Clinical Image
Source: Wikimedia Commons - Pneumonia X-ray - CC BY-SA 4.0
Case Presentation
A 72-year-old man with diabetes mellitus and chronic kidney disease presents with confusion, productive cough, and fever for 2 days. On arrival, vital signs show temperature 39.5C (103.1F), heart rate 125 bpm, respiratory rate 28/min, blood pressure 78/42 mmHg (MAP 54), and SpO2 88% on room air. He is started on supplemental oxygen and the sepsis bundle is initiated. Blood cultures and sputum cultures are obtained, and broad-spectrum antibiotics (ceftriaxone and azithromycin) are administered within 45 minutes. Lactate returns at 6.8 mmol/L. A 30 mL/kg crystalloid bolus (2.1L for 70 kg patient) is administered over 30 minutes. Post-fluid resuscitation, MAP increases to 58 mmHg but remains below target. A central venous catheter is placed in the right internal jugular vein, and norepinephrine is initiated at 0.1 mcg/kg/min. Norepinephrine is titrated to 0.3 mcg/kg/min over 2 hours, achieving MAP of 68 mmHg. Repeat lactate at 4 hours is 4.2 mmol/L, showing 38% clearance. By 12 hours, norepinephrine requirements increase to 0.5 mcg/kg/min despite adequate volume status (IVC greater than 2 cm with less than 50% collapsibility on bedside ultrasound). Vasopressin 0.03 units/min is added as a second agent. Hydrocortisone 50 mg IV every 6 hours is initiated for refractory shock requiring multiple vasopressors. Over the next 48 hours, with source control (aspiration pneumonia, treated with antibiotics), vasopressors are gradually weaned, and he is transferred out of the ICU on day 5.
Key Learning Points
- Norepinephrine is the first-line vasopressor for septic shock due to its potent alpha-1 vasoconstriction with modest beta-1 inotropy
- Vasopressin (0.03-0.04 units/min fixed dose) is added as a second-line agent when norepinephrine requirements exceed 0.25-0.5 mcg/kg/min to reduce catecholamine exposure
- Corticosteroids (hydrocortisone 200 mg/day) are indicated for septic shock refractory to fluids and requiring moderate-to-high dose vasopressors; they accelerate shock reversal
- Lactate clearance of greater than 10-20% every 2 hours indicates adequate resuscitation response; failure to clear suggests ongoing hypoperfusion or cellular dysfunction