A 36-year-old woman is brought to the emergency department 20 minutes after being involved in a high-speed motor vehicle collision. On arrival, she is unconscious. Her pulse is 140/min, respirations are 12/min and shallow, and blood pressure is 76/55 mm Hg. 0.9% saline infusion is begun. A focused assessment with sonography shows blood in the left upper quadrant of the abdomen. Her hemoglobin concentration is 7.6 g/dL and hematocrit is 22%. The surgeon decided to move the patient to the operating room for an emergent explorative laparotomy. Packed red blood cell transfusion is ordered prior to surgery. However, a friend of the patient asks for the transfusion to be held as the patient is a Jehovah's Witness. The patient has no advance directive and there is no documentation showing her refusal of blood transfusions. The patient's husband and children cannot be contacted. Which of the following is the most appropriate next best step in management?

Transfusion of packed red blood cells

Consult hospital ethics committee

Administer high-dose iron dextran

A 26-year-old woman is brought to the emergency department after a motor vehicle accident. She was driving on the highway when she was struck by a van. At the hospital she was conscious but was bleeding heavily from an open wound in her left leg. Pulse is 120/min and blood pressure is 96/68 mm Hg. She receives 3 L of intravenous saline and her pulse slowed to 80/min and blood pressure elevated to 116/70 mm Hg. The next morning she is found to have a hemoglobin of 6.2 g/dL. Her team decides to transfuse 1 unit of packed RBCs. Twenty minutes into the transfusion she develops a diffuse urticarial rash, wheezing, fever, and hypotension. The transfusion is immediately stopped and intramuscular epinephrine is administered. Which of the following scenarios is most consistent with this patient's reaction to the blood transfusion?

A patient history of frequent sinopulmonary infections

A patient history of cardiovascular disease

Unsanitary blood product storage practices in the hospital

Facial twitching when the patient's cheek is tapped

Prior transfusion reactions caused by the same donor

A 34-year-old primigravida was brought to an obstetric clinic with a chief complaint of painless vaginal bleeding. She was diagnosed with placenta praevia and transfused with 2 units of whole blood. Five hours after the transfusion, she developed a fever and chills. How could the current situation be prevented?

Transfusing leukocyte reduced blood products

Administering prophylactic epinephrine

ABO grouping and Rh typing before transfusion

Performing Coombs test before transfusion

Administering prophylactic immunoglobulins

Which of the following is true regarding nicotine substitution therapy?

There should be a 15-minute gap between nicotine gum and coffee/soda/acidic food as they decrease its absorption

Preferably given by gastrointestinal route.

Varenicline comes with a black box warning of cardiovascular death

Nicotine chewing gum is better for constant use as it gives 25% higher blood level than lozenges

An 18-year-old man presents to a rural emergency department after being stabbed multiple times. The patient's past medical history is notable for obesity, diabetes, chronic upper respiratory infections, a 10 pack-year smoking history, and heart failure. He is protecting his airway and he is oxygenating and ventilating well. His temperature is 97.6°F (36.4°C), blood pressure is 74/34 mmHg, pulse is 180/min, respirations are 24/min, and oxygen saturation is 98% on room air. The patient is started on whole blood and the surgeon on call is contacted to take the patient to the operating room. During the secondary survey, the patient complains of shortness of breath. His blood pressure is 54/14 mmHg, pulse is 200/min, respirations are 24/min, and oxygen saturation is 90% on room air. Physical exam is notable for bilateral wheezing on lung exam. The patient goes into cardiac arrest and after 30 minutes, attempts at resuscitation are terminated. Which of the following is associated with this patient's decompensation during resuscitation?

Persistent intraabdominal bleeding

Blood component therapy for USMLE Step 2 CK: High-Yield Surgery Lessons

Blood Components - The Blood Bag Breakdown

Blood component separation and derived products

Packed Red Blood Cells (PRBCs)
- Use: ↑ O₂ carrying capacity for anemia or acute blood loss.
- Effect: 1 unit ↑ Hb by 1 g/dL & Hct by 3%.
Platelets
- Use: For thrombocytopenia or platelet dysfunction.
- Thresholds: Give if <50,000/μL for surgery, or <10,000/μL for spontaneous bleed risk.
Fresh Frozen Plasma (FFP)
- Use: Replaces all clotting factors.
- Indications: Coagulopathy (liver disease, DIC), urgent warfarin reversal.
Cryoprecipitate
- Contains: Fibrinogen, Factor VIII, vWF, Factor XIII.
- Use: Hypofibrinogenemia (<100 mg/dL).

⭐ FFP is preferred for rapid warfarin reversal over Vitamin K due to its immediate supply of all coagulation factors.

Transfusion Indications - When to Open the Tap

Packed Red Blood Cells (PRBCs)
- Hb < 7 g/dL in stable, hospitalized patients.
- Hb < 8 g/dL in patients with cardiovascular disease or post-op.
- Symptomatic anemia (e.g., chest pain, dyspnea) or active hemorrhage.
Platelets
- Prophylactically if < 10,000/μL.
- Pre-procedure or active bleeding if < 50,000/μL.
Fresh Frozen Plasma (FFP)
- For coagulopathy (INR > 1.5) with active bleeding or pre-procedure.
- Warfarin reversal (when PCC is unavailable).
Cryoprecipitate
- For hypofibrinogenemia (< 100-150 mg/dL).

⭐ Massive Transfusion Protocol (MTP): In trauma or massive hemorrhage, use a 1:1:1 ratio of PRBCs:FFP:Platelets to prevent dilutional coagulopathy.

Transfusion Reactions - When Good Blood Goes Bad

Immediate Steps: Stop transfusion, maintain IV access (0.9% saline), check for clerical errors, and notify the blood bank.

Reaction Type	Onset	Pathophysiology	Key Features
Acute Hemolytic	< 1 hr	ABO incompatibility	Fever, flank pain, hemoglobinuria, +Direct Coombs
FNHTR	1-6 hrs	Cytokines from donor WBCs	Fever, chills. Prevent w/ leukoreduction.
Allergic	< 1 hr	IgE vs. plasma proteins	Urticaria, pruritus. Give antihistamines.
Anaphylactic	Seconds	Anti-IgA in IgA-deficient pt	Shock, angioedema. Give epinephrine.
TRALI	< 6 hrs	Donor anti-leukocyte Abs	Non-cardiogenic pulmonary edema (ARDS)
TACO	< 6 hrs	Volume overload	Cardiogenic pulmonary edema, ↑JVP, ↑BNP

Massive Transfusion - The 1:1:1 Protocol

Definition: Replacement of >1 blood volume in 24h, >10 units of pRBCs in 24h, or >4 units in 1h.
1:1:1 Protocol: Balanced transfusion with a ratio of 1 unit packed red blood cells (pRBCs) : 1 unit fresh frozen plasma (FFP) : 1 unit platelets.
Goal: Mimic whole blood to prevent/treat coagulopathy, acidosis, & hypothermia (lethal triad).
Complications: Hypocalcemia (citrate toxicity), hyperkalemia, hypothermia.

⭐ The 1:1:1 protocol has been shown to decrease mortality, reduce total blood product usage, and achieve hemostasis faster in trauma patients.

High‑Yield Points - ⚡ Biggest Takeaways

Packed Red Blood Cells (PRBCs) ↑ O₂-carrying capacity; 1 unit raises Hb by 1 g/dL.

Give platelets for thrombocytopenia or dysfunction, but avoid in TTP/HUS without severe bleeding.

Fresh Frozen Plasma (FFP) replaces all clotting factors; reverses warfarin and treats coagulopathy.

Cryoprecipitate provides concentrated fibrinogen, Factor VIII, and vWF; used for hypofibrinogenemia.

Febrile non-hemolytic is the most common reaction; acute hemolytic is the most severe.

O-negative is the universal RBC donor; AB is the universal plasma donor.

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