What is the appropriate evaluation and management of a sudden hemoglobin drop in a 66‑year‑old man with remote poliomyelitis who is postoperative after laparotomy and appendectomy for an appendiceal abscess, currently intubated with severe acute respiratory distress syndrome, on dual inotropic (vasopressor) support, and receiving continuous renal replacement therapy?

Evaluation and Management of Sudden Hemoglobin Drop in a Critically Ill Post-Laparotomy Patient

In this critically ill patient with multiple organ failures, immediately investigate for active bleeding (surgical site, gastrointestinal, retroperitoneal) while maintaining a restrictive transfusion threshold of hemoglobin 70 g/L (7 g/dL), with consideration for transfusion at 80 g/L (8 g/dL) given dual vasopressor support and severe ARDS suggesting compromised oxygen delivery. 1

Immediate Diagnostic Evaluation

Clinical Assessment

• Visually inspect surgical drains and wounds for evidence of active bleeding or hematoma formation, as surgical site bleeding is the most common cause of acute hemoglobin drop post-laparotomy 1
• Examine the abdomen for distension, firmness, or new peritoneal signs that may indicate intra-abdominal hemorrhage or abscess expansion 2, 3
• Monitor hemodynamic parameters closely: increasing vasopressor requirements, worsening tachycardia (if not masked by sedation), or falling urine output despite adequate RRT suggest ongoing blood loss 1
• Assess for signs of gastrointestinal bleeding: nasogastric aspirate for blood, melena, or hematochezia, as stress ulceration is common in critically ill patients on vasopressors 1

Laboratory Investigations

• Obtain immediate hemoglobin/hematocrit measurement to quantify the drop and establish baseline for serial monitoring 1
• Check coagulation profile (PT/INR, aPTT, fibrinogen, platelet count) as critical illness, sepsis, and RRT can induce coagulopathy 1
• Measure lactate and mixed venous oxygen saturation (if available) to assess adequacy of oxygen delivery and detect occult tissue hypoperfusion 1
• Repeat hemoglobin every 4-6 hours if bleeding is suspected, or more frequently if hemodynamically unstable 1

Imaging Studies

• Perform urgent CT abdomen/pelvis with IV contrast (if renal function permits despite RRT) to identify:
  • Intra-abdominal hematoma or active extravasation 2, 3
  • Abscess expansion or new collection formation 2, 3
  • Retroperitoneal bleeding (especially given recent laparotomy and RRT catheter placement) 1
• Consider bedside ultrasound if patient is too unstable for CT transport, to detect free fluid or organized collections 2

Transfusion Decision Algorithm

Hemoglobin Thresholds

• Transfuse at hemoglobin <70 g/L (7 g/dL) in hemodynamically stable patients without active bleeding 1
• Consider transfusion at hemoglobin <80 g/L (8 g/dL) in this patient given:
  • Dual vasopressor requirement indicating cardiovascular instability 1
  • Severe ARDS with compromised oxygenation reducing physiologic reserve 1
  • Signs of organ ischemia (rising lactate, oliguria despite RRT, worsening mental status) 1

Transfusion Strategy

• Administer one unit of packed red blood cells at a time and reassess hemoglobin and clinical status before giving additional units 1
• Target post-transfusion hemoglobin of 70-90 g/L (7-9 g/dL) to balance oxygen delivery against transfusion-related complications 1
• Avoid liberal transfusion (target >100 g/L) as this increases mortality and complications without improving outcomes 1

Management of Identified Bleeding Sources

Surgical Site Bleeding

• Consult surgery urgently if drains show increasing bloody output, abdominal distension develops, or hemoglobin continues dropping despite transfusion 1, 3
• Consider return to operating room for exploration if:
  • Hemoglobin drops >20 g/L despite 2-3 units transfused 1
  • Imaging shows expanding hematoma or active extravasation 3
  • Hemodynamic instability worsens despite resuscitation 1

Coagulopathy Management

• Transfuse platelets if count <50 × 10⁹/L in the setting of active bleeding 1
• Administer fresh frozen plasma (FFP) if INR >1.5 and bleeding is present or anticipated 1
• Give cryoprecipitate if fibrinogen <1.5 g/L to support clot formation 1
• Consider point-of-care testing (thromboelastography) if available to guide targeted component therapy 1

Gastrointestinal Bleeding

• Start proton pump inhibitor infusion (if not already on prophylaxis) for stress ulcer prevention 1
• Consult gastroenterology for endoscopy if upper GI bleeding is suspected and patient can be stabilized 1

Special Considerations in This Patient

RRT-Related Issues

• Assess RRT circuit and catheter site for occult bleeding, as anticoagulation (if used) can contribute to blood loss 1
• Adjust RRT anticoagulation (citrate vs. heparin) if coagulopathy or bleeding is present 1

Infection and Abscess Concerns

• Maintain high suspicion for abscess expansion or new collection given recent appendiceal abscess and laparotomy 2, 3
• Elevated CRP and persistent fever despite antibiotics may indicate abscess requiring drainage rather than simple bleeding 2
• Consider laparoscopic drainage if percutaneous approach is not feasible and abscess is contributing to clinical deterioration 3

Glucose Control

• Maintain blood glucose 7.7-10 mmol/L (140-180 mg/dL) using variable-rate insulin infusion, as hyperglycemia impairs immune function and wound healing in this septic patient 1

Common Pitfalls to Avoid

• Do not delay imaging in a hemodynamically stable patient; CT is essential to differentiate bleeding from abscess expansion 2, 3
• Do not transfuse to "normal" hemoglobin levels (>100 g/L); restrictive strategy improves outcomes in critically ill patients 1
• Do not ignore non-hemorrhagic causes of hemoglobin drop: hemodilution from fluid resuscitation, hemolysis from sepsis or RRT, or laboratory error 1
• Do not overlook retroperitoneal bleeding from RRT catheter placement, which may not be clinically obvious 1
• Do not assume all hemoglobin drops require transfusion; assess oxygen delivery markers (lactate, SvO₂, urine output) rather than hemoglobin alone 1