Case Summary

Patient Profile

• 78-year-old female
• Frail, 40 kg
• Hypertensive
• Advanced chronic kidney disease (CKD)

Baseline Status

• Renal function: Creatinine 4 mg/dL, Urea 70 mg/dL, urine output 800 ml/day
• Hemodynamics: HR 55/min, BP 130/84 mmHg, echocardiogram shows preserved EF
• Hematology: Hemoglobin 9 g/dL, microcytic normochromic anemia

Surgical Course

• Procedure: Hip arthroplasty under general anesthesia
• Intraoperative inputs: 1 PRBC + 500 ml Plasma-Lyte
• Post-op urine output: 200 ml in 3 hours

Crisis Event (4 Hours Post-Op)

• BP: 60/40 mmHg
• HR: 54/min
• Hb: Fell to 7.3 g/dL
• Echo: Preserved contractility, collapsed IVC (suggesting hypovolemia)
• Urine output: 20 ml/hr

Therapy Given

• Fluids and blood: 2 crystalloids + 2 PRBC
• Nephrology: Fluid restriction ≤1.5 L/day
• Colloid: Gelofusine started
• Vasopressor: Norepinephrine infusion ~0.64 µg/kg/min

Pathophysiological Considerations

Aging and Hemodynamics

• Reduced β-adrenergic responsiveness → blunted tachycardic response
• Increased arterial stiffness → impaired vasodilatory reserve
• Decreased ventricular compliance → preload dependence

CKD Pathophysiology

• Electrolyte derangements: hyperkalemia, metabolic acidosis risk
• Anemia: chronic due to reduced erythropoietin
• Vasculature: endothelial dysfunction, vascular calcification
• Hemostasis: platelet dysfunction with bleeding tendency

Postoperative Hypotension in CKD

• Multifactorial: hypovolemia, third-spacing, bleeding, vasodilation, impaired stress response
• Resuscitation challenge: fluid therapy limited by pulmonary edema risk

Diagnostic Approach

Initial Priorities

• Airway, breathing, circulation assessment
• Continuous monitoring: ECG, SpO₂, arterial line if feasible
• Key labs: hemoglobin, electrolytes, ABG, lactate

POCUS Findings

• Preserved LV function: cardiogenic shock excluded
• Collapsed IVC: hypovolemia indicated
• Clear lungs: no pulmonary edema

Differential Diagnoses

• Hypovolemia: probable
• Ongoing hemorrhage: possible
• Sepsis/vasoplegia: possible
• MI/arrhythmia: unlikely

Fluid Resuscitation in CKD

Crystalloids

• Balanced solutions (Ringer’s lactate, Plasma-Lyte) preferred
• Avoid normal saline (risk of hyperchloremic acidosis)
• Limit volume to reduce pulmonary edema risk

Colloids

• Gelofusine: rapid but short-lived expansion
• Starches: contraindicated (AKI and mortality risk)

Blood Transfusion

• Hb drop to 7.3 g/dL justifies transfusion
• Restrictive threshold: <7 g/dL in general ICU patients
• In elderly CKD with ischemic risk: aim ≥8 g/dL

Vasopressor and Inotrope Strategy

• Norepinephrine: first-line; target MAP 65–70 mmHg
• Vasopressin: adjunct if refractory vasodilation
• Dobutamine: if cardiac dysfunction develops
• Adrenaline: salvage therapy

Caution: Excessive vasoconstriction may reduce renal perfusion in CKD.

Multidisciplinary Decision-Making

Team Priorities

• Nephrology: restrict fluids ≤1.5 L/day
• Anesthesia/ICU: prioritize perfusion even if above restriction
• Surgery: exclude ongoing bleeding

Strategy

• Echo and IVC-guided bolus trials
• Avoid blind fluid loading
• Align team decisions around perfusion endpoints

Molecular Pathways in Collapse

• Systemic inflammatory response: cytokines (TNF-α, IL-6) cause capillary leak, NO-mediated vasodilation, and microthrombosis
• Mitochondrial dysfunction: cytopathic hypoxia → oxygen present but ATP not generated
• Neurohumoral dysregulation: receptor desensitization to catecholamines → vasopressor resistance
• Coagulopathy: endothelial injury → microcirculatory failure despite adequate BP

Clinical Insight: Restoring BP alone is not sufficient; cellular oxygen utilization must be re-established.

Clinical Features of Postoperative Collapse

Timing and Triggers

• Usually within first 6–12 hours post-op
• Triggers include hemorrhage, sepsis, pulmonary embolism, myocardial infarction, inadequate analgesia

Early Clinical Signs

• Vital signs: narrowing pulse pressure, relative hypotension, tachycardia
• Skin: cold and clammy (low-output shock) or warm (vasodilatory shock)
• Respiratory: tachypnea, hypoxemia
• Neurological: agitation, confusion, restlessness

Laboratory/Bedside Indicators

• Rising lactate >2 mmol/L: tissue hypoperfusion
• Base deficit: metabolic acidosis
• Urine output <0.5 ml/kg/h: renal hypoperfusion
• SvO₂ <65%: inadequate oxygen delivery

Diagnostic Approach in ICU

Structured Steps

1. Airway & breathing: ABG, CXR or lung ultrasound
2. Circulation: ECG, bedside echo, arterial line, central venous monitoring
3. Laboratory: CBC, coagulation, troponins, lactate, renal/liver function
4. Differentials: hypovolemia, hypoxia, acidosis, electrolyte imbalance, tamponade, PE, MI, drug effect
5. Advanced imaging: CT angiography (bleed, PE), CT brain if neurologic

Insight: Bedside echocardiography is now first-line for shock differentiation.

Therapeutic Strategies

Fluid Resuscitation

• Balanced crystalloids preferred
• Albumin safe but no mortality benefit (SAFE trial)
• Avoid hydroxyethyl starches

Blood Products

• PRBC for Hb <7 g/dL (general ICU) or <8 g/dL (elderly/ischemia risk)
• Platelet/FFP guided by viscoelastic testing

Vasopressors

• First-line: norepinephrine
• Add vasopressin if refractory
• Epinephrine for combined inotropy and vasoconstriction
• Phenylephrine for isolated vasoplegia

Inotropes

• Dobutamine in low cardiac output states
• Milrinone/levosimendan in RV dysfunction or pulmonary hypertension

Mechanical Support

• IABP or VA-ECMO in refractory cases

Adjunctive Therapies

• Hydrocortisone in refractory septic shock
• Renal replacement therapy for oliguria, acidosis, hyperkalemia, fluid overload
• Early antibiotics if infection suspected

Teaching Integration

Physics: MAP = CO × SVR

Molecular: CaO₂ and norepinephrine α1 receptor signaling

Guidelines:

• ESAIC: Hb ≥8 g/dL in elderly CKD
• ASA: MAP ≥70 mmHg to preserve renal autoregulation

Conclusion

This patient remains unstable despite transfusion, fluids, and moderate norepinephrine. The most likely state is persistent hypovolemia, but nephrology’s fluid restriction necessitates precision resuscitation.

Key Management Steps

• Echo-guided small bolus trials
• Norepinephrine titration ± vasopressin
• Maintain Hb ≥8 g/dL
• Monitor perfusion endpoints: urine output, lactate, ScvO₂, NIRS

This case highlights the challenge of balancing perfusion optimization with the risks of fluid overload in elderly CKD patients—requiring continuous reassessment and multidisciplinary alignment.