Postoperative bleeding

Etiology & Risk Factors - Leaky Pipes, Bad Blood

• Surgical ("Leaky Pipes"): Most common cause.
  • Inadequate hemostasis during surgery.
  • Slipped ligature or dislodged clot from a vessel.
  • Injury to adjacent vessels or organ parenchyma.
• Coagulopathic ("Bad Blood"):
  • Pre-existing: Hemophilia, von Willebrand disease, platelet disorders.
  • Acquired: Anticoagulant/antiplatelet meds (e.g., Warfarin, DOACs), dilutional coagulopathy from massive transfusion, DIC, uremia, liver failure.
• Medical:
  • Postoperative hypertension stressing anastomoses.
  • Hypothermia, which impairs the coagulation cascade.

⭐ The most common cause of postoperative bleeding is a technical error, i.e., inadequate mechanical hemostasis, not a primary coagulopathy.

Clinical Presentation & Diagnosis - Spotting Red Flags

• Bleeding Manifestations:

  • Overt: Visible blood from drains, wounds, or chest tubes; hematemesis, melena.
  • Concealed: Signs of hypovolemia without obvious loss. Think retroperitoneum, thorax, or pelvis. Presents with tachycardia, hypotension, oliguria.

• Diagnostic Workflow:

  • Vitals & Exam: Check for tachycardia (often earliest sign), hypotension, cool/clammy skin, and ↓ urine output (< 0.5 mL/kg/hr).
  • Labs: Serial CBC (Hgb/Hct), PT/INR, aPTT, fibrinogen.
  • Imaging: Bedside FAST scan for quick assessment; CT angiography is gold standard for localizing the bleed.

⭐ In acute hemorrhage, Hgb/Hct may be initially normal due to proportional loss of plasma and red cells. Serial measurements are key.

Management - Plugging the Dam

Initial stabilization is paramount. Follow resuscitation principles before targeting the source.

• Initial Steps:

  • Assess ABCs (Airway, Breathing, Circulation).
  • Secure 2 large-bore IV lines.
  • Begin aggressive fluid resuscitation with crystalloids (e.g., Normal Saline, Lactated Ringer's).

• Transfusion Strategy:

  • Administer blood products for hemodynamic instability or significant hemoglobin drop.
  • Activate Massive Transfusion Protocol (MTP) for severe hemorrhage, targeting a ratio of $1:1:1$ (pRBCs:FFP:Platelets).

⭐ The Lethal Triad: Be vigilant for the deadly combination of acidosis, hypothermia, and coagulopathy in massive hemorrhage. Each component worsens the others, creating a vicious cycle.

Complications & Special Cases - The Vicious Cycle

Uncontrolled bleeding progresses to hemorrhagic shock, a primary complication classified by severity.

• ⚠️ The Lethal Triad: A self-perpetuating cycle where hemorrhage causes:
  • Hypothermia: Impairs clotting factor enzymatic activity.
  • Acidosis: Reduces enzyme efficiency in the coagulation cascade.
  • Coagulopathy: Worsens bleeding, completing the cycle.
• High-Risk Surgeries: Cardiac (especially on bypass), liver resections, major vascular surgery.

⭐ In massive transfusions, citrate in blood products chelates calcium, causing iatrogenic hypocalcemia. This is a critical, reversible driver of coagulopathy.

• Postoperative bleeding within 24 hours is most often due to technical error (e.g., a slipped ligature).
• Tachycardia is the earliest sign, often preceding hypotension and oliguria.
• A falling hematocrit is a key lab finding but may lag by several hours after acute blood loss.
• Delayed bleeding suggests erosion into a vessel or an underlying coagulopathy.
• Management is aggressive fluid resuscitation and prompt surgical re-exploration for significant, uncontrolled bleeding.