ICU Map

Renal Replacement Therapy & CRRT Initiation

From urgent 'AEIOU' indication screening and modality selection to vascular access, dosing, and anticoagulation.

RecognizeAssessDecideDifferentialInterveneReassess
Severe Acute Kidney Injury (KDIGO Stage 3) / Metabolic Urgency
Assessment StepEvaluate urgent 'AEIOU' indications for emergency dialysisExplore Topic
Consider emergent KRT for life-threatening/refractory acid-base or electrolyte disturbances, selected dialyzable intoxications, refractory volume overload, or serious uremic complications. Use the clinical trajectory rather than a single creatinine, BUN, potassium or pH cutoff.
Decision PointSelect RRT modality based on hemodynamic stability
CRRT is often favored when hemodynamic instability or elevated ICP makes slower fluid and osmotic shifts desirable; IHD/SLED remain appropriate in selected patients according to urgency, hemodynamic tolerance, local expertise, and the solute-removal goal.
Clinical ActionInsert temporary non-tunneled dialysis catheter
Preferred site: Right Internal Jugular vein under real-time ultrasound guidance. Second-line: Femoral vein (>=20–24 cm length catheter). Avoid subclavian vein to prevent central vein stenosis.
Clinical ActionPrescribe delivered effluent dose: 20–25 mL/kg/hourExplore Topic
KDIGO guideline standard. Prescribe 25–30 mL/kg/h to account for expected downtime (filter clotted, procedures, bag changes).
Decision PointSelect circuit anticoagulation strategy
Regional citrate anticoagulation (RCA) is generally preferred for CRRT when feasible because it prolongs circuit life and reduces bleeding versus systemic heparin. Choose systemic anticoagulation or anticoagulation-free strategies according to bleeding risk, other indications for anticoagulation, metabolic tolerance, and local protocol.
Differential Branches (2)
1Branch
Reassessment / LoopRegional Citrate: Monitor post-filter iCa & Total/Free Calcium ratio
Target post-filter ionized Ca 0.25–0.35 mmol/L. Monitor systemic ionized Ca (target 1.1–1.3) and total-to-ionized calcium ratio (<2.5 to exclude citrate accumulation).
2Branch
Reassessment / LoopHeparin / No Anticoagulation: Monitor circuit pressures & filter life
Track transmembrane pressure (TMP) and filter pressure drop. Flush circuit periodically with normal saline if no anticoagulation used.

An educational representation of clinical reasoning, not a diagnostic algorithm or personalized medical advice — always apply clinical judgment and institutional protocols.

Caution

Escalate — Red Flags & Critical Warnings

  • Suspected citrate accumulation — rising total-to-ionized calcium ratio (often >2.5), increasing calcium requirement, systemic ionized hypocalcemia and worsening acid-base status. Reduce citrate and optimize clearance/perfusion; discontinue RCA when overt accumulation persists and correct calcium/metabolic abnormalities.
  • Rapid BUN reduction causing severe cerebral edema and seizures (Dialysis Disequilibrium Syndrome) — use gentle initiation (low blood flow rate, short duration, or CRRT) in patients with baseline BUN > 100–150 mg/dL.

Related Bedside Clinical Problems (17)

Bedside Presentations
New Tachycardia & Tachyarrhythmias

Algorithmic triage of acute heart rates > 100–150 bpm: stability screen (immediate cardioversion if unstable), narrow vs wide QRS differentiation, Brugada VT rules, and sinus tachycardia etiology search.

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New Bradycardia & Conduction Blocks

Acute bradyarrhythmia management: identifying hemodynamic instability, distinguishing sinus node arrest vs high-grade AV block, medical chronotropic support (atropine, epinephrine), and emergent pacing.

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Acute Altered Mental Status & ICU Delirium

Systematic neurologic evaluation: immediate metabolic/toxic screening (glucose, hypoxia, hypercapnia), nonconvulsive status epilepticus exclusion, structural CT triage, and CAM-ICU delirium management.

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Linked Deep-Dive Topics (6)

Reference Knowledge
Continuous Renal Replacement Therapy (CRRT)renal

Principles of convection vs diffusion, filtration fraction, delivered effluent dosing (20–25 mL/kg/h), Regional Citrate Anticoagulation, and citrate toxicity.

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Acute Kidney Injury in Critical Carerenal

Sepsis-AKI microcirculatory decoupling, KDIGO staging, Furosemide Stress Test (FST), urine microscopy, and the AEIOU dialysis threshold framework.

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Metabolic Acidosis: HAGMA, NAGMA, & Bicarbonate Evidencerenal

Differential diagnosis (GOLD MARK vs HARDCARP), toxic alcohol osmolar gaps, Urine Anion Gap, and current sodium bicarbonate evidence including BICAR-ICU and BICARICU-2.

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Severe Hyperkalemia in Critical Illnessrenal

Nernst resting potential mechanics, ECG progression, the 3-step resuscitation framework (Stabilize, Shift, Eliminate), and post-dialysis rebound kinetics.

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Severe Sodium Disorders: Hyponatremia & Hypernatremiarenal

Tonicity assessment, etiologic classification, 3% hypertonic saline bolus protocols, individualized ODS-safe correction limits, DDAVP relowering, DI diagnostics, and evidence-aware hypernatremia correction.

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Toxicologic Emergencies in Critical Caretoxicology

Resuscitate first, identify toxidromes and ECG/acid-base threats, use toxin-specific antidotes, and escalate early to poison-center, extracorporeal, or ECLS support when physiology demands it.

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