A 28-year-old research assistant is brought to the emergency department for severe chemical burns 30 minutes after accidentally spilling hydrochloric acid on himself. The burns cover both hands and forearms. His temperature is 37°C (98.6°F), pulse is 112/min, respirations are 20/min, and blood pressure is 108/82 mm Hg. Initial stabilization and resuscitation is begun, including respiratory support, fluid resuscitation, and cardiovascular stabilization. The burned skin is irrigated with saline water to remove the chemical agent. Which of the following is the most appropriate method to verify adequate fluid infusion in this patient?

Pulmonary capillary wedge pressure

A 32-year-old woman comes to the office for a regular follow-up. She was diagnosed with type 2 diabetes mellitus 4 years ago. Her last blood test showed a fasting blood glucose level of 6.6 mmol/L (118.9 mg/dL) and HbA1c of 5.1%. No other significant past medical history. Current medications are metformin and a daily multivitamin. No significant family history. The physician wants to take her blood pressure measurements, but the patient states that she measures it every day in the morning and in the evening and even shows him a blood pressure diary with all the measurements being within normal limits. Which of the following statements is correct?

The physician has to measure the patient’s blood pressure because it is a standard of care for any person with diabetes mellitus who presents for a check-up.

Assessment of blood pressure only needs to be done at the initial visit; it is not necessary to measure blood pressure in this patient at any follow-up appointments.

The physician should not measure the blood pressure in this patient and should simply make a note in a record showing the results from the patient’s diary.

The physician should not measure the blood pressure in this patient because she does not have hypertension or risk factors for hypertension.

The physician should not measure the blood pressure in this patient because the local standards of care in the physician's office differ from the national standards of care so measurements of this patient's blood pressure cannot be compared to diabetes care guidelines.

An 82-year-old male with congestive heart failure experiences rapid decompensation of his condition, manifesting as worsening dyspnea, edema, and increased fatigue. Labs reveal an increase in his serum creatinine from baseline. As part of the management of this acute change, the patient is given IV dobutamine to alleviate his symptoms. Which of the following effects occur as a result of this therapy?

Increased myocardial oxygen consumption

Decreased cardiac contractility

Increased systemic vascular resistance due to systemic vasoconstriction

Slowed atrioventricular conduction velocities

A 75-year-old male arrives by ambulance to the emergency room severely confused. His vitals are T 40 C, HR 120 bpm, BP 80/55 mmHg, RR 25. His wife explains that he injured himself about a week ago while cooking, and several days later his finger became infected, oozing with pus. He ignored her warning to see a doctor and even refused after he developed fever, chills, and severe fatigue yesterday. After being seen by the emergency physician, he was given antibiotics and IV fluids. Following initial resuscitation with IV fluids, he remains hypotensive. The ED physicians place a central venous catheter and begin infusing norepinephrine. Which of the following receptors are activated by norepinephrine?

Alpha 1, Alpha 2, Beta 1, Beta 2

A 60-year-old woman is brought to the emergency department by paramedics after being found unresponsive. It is not possible to obtain a history. Her blood pressure is 75/30 mmHg and pulse is 108/min. Her extremities are cool and mottled. She is admitted to the intensive care unit (ICU) for further supportive care, where she is started on a norepinephrine intravenous drip. After several hours on this infusion, which of the following changes in vitals would be expected?

Blood pressure increases; pulse decreases

Blood pressure decreases; pulse decreases

Blood pressure increases; pulse increases

Blood pressure decreases; pulse increases

Blood pressure increases; pulse remains unchanged

A 35-year-old woman volunteers for a study on respiratory physiology. Pressure probes A and B are placed as follows: Probe A: between the parietal and visceral pleura Probe B: within the cavity of an alveolus The probes provide a pressure reading relative to atmospheric pressure. To obtain a baseline reading, she is asked to sit comfortably and breathe normally. Which of the following sets of values will most likely be seen at the end of inspiration?

Probe A: -6 mm Hg; Probe B: 0 mm Hg

Probe A: 0 mm Hg; Probe B: -1 mm Hg

Probe A: -4 mm Hg; Probe B: 0 mm Hg

Probe A: -4 mm Hg; Probe B: -1 mm Hg

Probe A: -6 mm Hg; Probe B: -1 mm Hg

A 38-year-old previously healthy woman develops septic shock from necrotizing fasciitis of the lower extremity. Despite three debridements, broad-spectrum antibiotics (vancomycin, meropenem, clindamycin), IVIG, and aggressive critical care support, she develops refractory shock requiring norepinephrine 1.2 mcg/kg/min, vasopressin 0.04 units/min, and epinephrine 0.1 mcg/kg/min. Lactate is 15 mmol/L. Surgical team recommends hemipelvectomy as last option for source control. Family is devastated. ICU team notes SOFA score of 18. Synthesize an approach to management and decision-making.

Multidisciplinary meeting with surgery, ICU, palliative care, and family to discuss realistic outcomes, quality of life, and patient values before decision

Transfer to ECMO center for consideration of VA-ECMO as bridge to hemipelvectomy

Continue medical management for 24 hours and proceed with hemipelvectomy only if shock improves

Decline surgery based on futility given SOFA score >15 and initiate comfort care

Proceed with hemipelvectomy immediately as only chance for survival with informed consent from family

A 52-year-old woman with septic shock from intra-abdominal infection undergoes emergency exploratory laparotomy for perforated diverticulitis with fecal peritonitis. Surgery reveals extensive contamination requiring damage control approach. Postoperatively, she requires norepinephrine 0.8 mcg/kg/min plus vasopressin 0.04 units/min, has lactate of 8.5 mmol/L, temperature 35.2°C, INR 2.8, pH 7.18, and base deficit -12. Planned return to OR is in 48 hours. Evaluate the priority interventions to optimize outcome.

Aggressive rewarming, correction of coagulopathy, ongoing resuscitation, and source control at planned reoperation

Immediate return to OR for definitive repair and anastomosis

Start therapeutic hypothermia and delay reoperation until hemodynamically stable off vasopressors

Initiate high-dose vasopressors to maintain MAP >75 mmHg and early enteral nutrition

Administer massive transfusion protocol and emergency re-exploration within 6 hours

A 70-year-old man with recently diagnosed small cell lung cancer presents with septic shock from pneumonia. After initial resuscitation, he requires norepinephrine 0.6 mcg/kg/min and has a lactate of 7.8 mmol/L. His SOFA score is 14. The family requests 'everything be done,' but the patient had previously told his oncologist he would not want prolonged intensive care if his cancer prognosis was poor. Staging shows extensive-stage disease. The ICU team debates goals of care. What represents the most ethically appropriate approach to decision-making?

Arrange urgent palliative care consultation and family meeting to discuss patient's previously expressed wishes and realistic prognosis

Continue maximum therapy per family wishes as they are legal decision-makers

Obtain ethics consultation to overrule family wishes based on futility

Continue current therapy for 72 hours then reassess based on clinical trajectory

Transition to comfort care based on poor oncologic prognosis and high SOFA score

Vasopressors and inotropic support for USMLE Step 3: High-Yield Management Lessons

Goals of Therapy - Squeeze the Pipes

Primary Goal: Maintain Mean Arterial Pressure (MAP) ≥ 65 mmHg to ensure adequate organ perfusion.
MAP is estimated as $1/3(SBP) + 2/3(DBP)$.

⭐ Add Dobutamine for persistent hypoperfusion (e.g., elevated lactate) and evidence of myocardial dysfunction (e.g., low cardiac index on echo) despite achieving the MAP goal.

Norepinephrine - The Alpha Dog

First-line vasopressor for septic shock (Surviving Sepsis Campaign).
Mechanism: Potent α1-agonist >> β1-agonist activity.
- α1 stimulation → intense peripheral vasoconstriction → ↑ SVR & ↑ MAP.
- β1 stimulation → modest ↑ inotropy & chronotropy → ↑ Cardiac Output.
Hemodynamic Profile:
- Primarily ↑ MAP through ↑ SVR.
- Cardiac output may increase, stay stable, or decrease (due to reflex bradycardia).

⭐ Exam Favorite: Norepinephrine is superior to dopamine for septic shock as it's associated with a lower risk of arrhythmias and improved mortality.

Adjunctive Agents - The Backup Squeezers

Vasopressin: For refractory shock to ↓ norepinephrine needs. Acts on V1 receptors causing pure vasoconstriction. Typical dose is 0.03 units/minute.
Epinephrine: Add-on therapy if MAP targets are unmet. Potent β1 and α1 effects, but risk of tachyarrhythmias and ↑ lactate.
Corticosteroids: Consider for refractory shock despite adequate fluids and pressors.
- Hydrocortisone IV, often 200 mg/day.

⭐ For patients on norepinephrine or epinephrine, adding vasopressin is associated with a lower rate of atrial fibrillation. It acts as a catecholamine-sparing agent.

Inotropic Support - Whip the Heart

Used for persistent hypoperfusion and cardiac dysfunction despite adequate fluid and vasopressor therapy (MAP ≥65 mmHg).

Goal: Increase cardiac output (CO) and improve end-organ perfusion.
Primary Agent: Dobutamine
- Mechanism: Primarily a β1-agonist → ↑ contractility & heart rate.
- Dosing: 2-20 mcg/kg/min.
Alternative: Epinephrine
- Provides both potent inotropic (β1) and vasopressor (α1) support.

⭐ Dobutamine's β2-agonist activity can cause peripheral vasodilation, potentially worsening hypotension. Ensure patient is on a vasopressor first.

Monitoring & Titration - Watchful Waiting

Goal: Titrate to the lowest effective dose to maintain target MAP (>65 mmHg) and ensure adequate end-organ perfusion.
Frequent Reassessment:
- Arterial Line: For continuous, real-time MAP monitoring.
- Lactate Clearance: Check q4-6h; indicates resolving shock.
- Urine Output: Target >0.5 mL/kg/hr.
- CVP & ScvO2: Targets 8-12 mmHg & >70% respectively.
Weaning: Gradually ↓ dose when stable and lactate normalizes. Avoid abrupt discontinuation.

⭐ Persistent ↑ lactate despite an adequate MAP is a poor prognostic sign, suggesting ongoing tissue hypoperfusion or mitochondrial dysfunction.

Early Vasopressor Initiation and Titration in Septic Shock

High‑Yield Points - ⚡ Biggest Takeaways

Norepinephrine is the first-line vasopressor for septic shock, targeting a MAP ≥65 mmHg.

Vasopressin is a common second-line agent added to norepinephrine; it is not titrated.

Add dobutamine for signs of myocardial dysfunction (e.g., low cardiac output) despite adequate fluid and vasopressor therapy.

Epinephrine can be an alternative or add-on to norepinephrine.

An arterial line is essential for accurate, continuous blood pressure monitoring.

Watch for peripheral ischemia as a major side effect.

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