Therapeutic Plasma Exchange (TPE) Guide
Comprehensive clinical guide to therapeutic plasma exchange (TPE), covering indications, modality selection, dosing strategies, replacement fluids, anticoagulation, monitoring, and complication management across critical care settings.
Definition
Therapeutic plasma exchange (TPE) is an extracorporeal procedure that removes a patient’s plasma and replaces it with a substitute fluid. Its objectives are to eliminate circulating pathogenic substances—autoantibodies, immune complexes, toxins, monoclonal proteins—and, when required, to supply deficient plasma factors. Clinical goals include halting immune-mediated tissue damage, reversing organ failure (e.g. in TTP or Guillain-Barré syndrome) and bridging to definitive therapy.
Types of Therapeutic Plasma Exchange
Membrane TPE
Centrifugal TPE
Techniques Comparison
| Aspect | Membrane TPE | Centrifugal TPE |
|---|---|---|
| Mechanism | Separation across a semi-permeable plasma filter (pore ≈0.3–0.5 µm); size-based filtration | Density-based separation in a spinning bowl or rotor; plasma layers off from cells |
| Versatility | Primarily plasma exchange; limited to filters rated for plasma separation | Can perform red-cell or platelet apheresis by tuning centrifugation settings |
| Vascular Access | Central venous catheter | Needles in arm veins or Central venous catheter |
| Replacement Volume | 3 liters of 5 % albumin | 3 liters of 5 % albumin |
| Plasma Removal Rate | ~35 mL/min | ~35 mL/min |
| Plasma Extraction Ratio | ~35 % (30–35 %) | ~85 % (75–85 %) |
| Plasma Flow Rate | ~100 mL/min | ~42 mL/min |
| Blood Flow Rate (Hct 40 %) | ~165 mL/min (150–200 mL/min required for mTPE) | ~70 mL/min (50–120 mL/min acceptable for cTPE) |
| Anticoagulation | Systemic unfractionated heparin is standard; citrate optional (≈1:20) | Citrate (ACD-A ≈1:12 with whole blood) is standard; calcium supplementation required |
| If Citrate Used | 8 mL/min, minus 35 % ≈ 5 mL/min to patient | 6 mL/min to machine, minus 85 % ≈ 1 mL/min to patient |
Mechanism
- Membrane TPE
- Separation across a semi-permeable plasma filter (pore ≈0.3–0.5 µm); size-based filtration
- Centrifugal TPE
- Density-based separation in a spinning bowl or rotor; plasma layers off from cells
Versatility
- Membrane TPE
- Primarily plasma exchange; limited to filters rated for plasma separation
- Centrifugal TPE
- Can perform red-cell or platelet apheresis by tuning centrifugation settings
Vascular Access
- Membrane TPE
- Central venous catheter
- Centrifugal TPE
- Needles in arm veins or Central venous catheter
Replacement Volume
- Membrane TPE
- 3 liters of 5 % albumin
- Centrifugal TPE
- 3 liters of 5 % albumin
Plasma Removal Rate
- Membrane TPE
- ~35 mL/min
- Centrifugal TPE
- ~35 mL/min
Plasma Extraction Ratio
- Membrane TPE
- ~35 % (30–35 %)
- Centrifugal TPE
- ~85 % (75–85 %)
Plasma Flow Rate
- Membrane TPE
- ~100 mL/min
- Centrifugal TPE
- ~42 mL/min
Blood Flow Rate (Hct 40 %)
- Membrane TPE
- ~165 mL/min (150–200 mL/min required for mTPE)
- Centrifugal TPE
- ~70 mL/min (50–120 mL/min acceptable for cTPE)
Anticoagulation
- Membrane TPE
- Systemic unfractionated heparin is standard; citrate optional (≈1:20)
- Centrifugal TPE
- Citrate (ACD-A ≈1:12 with whole blood) is standard; calcium supplementation required
If Citrate Used
- Membrane TPE
- 8 mL/min, minus 35 % ≈ 5 mL/min to patient
- Centrifugal TPE
- 6 mL/min to machine, minus 85 % ≈ 1 mL/min to patient
Goals of Plasma Exchange
Target substances for removal
Directly related to the disease; removal provides proven benefit
Not eliminated by kidneys or liver
Small volume of distribution (< 0.2 L/kg)
Large molecules (> 30 kDa) or protein-bound molecules
Low synthesis rate
Harmful and cannot be prevented by other treatments
Target substances for replacement
Directly related to the disease and their replacement provides benefit
Deficient in plasma; supplementation helps the patient
Replacement fluid is chosen according to pathology and patient needs
ASFA Categories
| Therapeutic Role | Selected Examples | |
|---|---|---|
| I | First-line therapy | Thrombotic thrombocytopenic purpura (TTP); Guillain-Barré syndrome; Goodpasture’s disease |
| II | Second-line / adjunct | Myasthenia gravis (moderate–severe); Severe SLE flare; ANCA-vasculitis with renal failure |
| III | Individualised decision | Hypertriglyceridaemic pancreatitis; Sepsis with multi-organ failure; Atypical HUS |
| IV | Evidence shows little benefit | Chronic lupus nephritis; ALS; Antepartum HELLP (use postpartum instead) |
I
- Therapeutic Role
- First-line therapy
- Selected Examples
- Thrombotic thrombocytopenic purpura (TTP); Guillain-Barré syndrome; Goodpasture’s disease
II
- Therapeutic Role
- Second-line / adjunct
- Selected Examples
- Myasthenia gravis (moderate–severe); Severe SLE flare; ANCA-vasculitis with renal failure
III
- Therapeutic Role
- Individualised decision
- Selected Examples
- Hypertriglyceridaemic pancreatitis; Sepsis with multi-organ failure; Atypical HUS
IV
- Therapeutic Role
- Evidence shows little benefit
- Selected Examples
- Chronic lupus nephritis; ALS; Antepartum HELLP (use postpartum instead)
Plasma-Volume Formula and Session Dosing
Estimated plasma volume ≈ 0.065 × weight (kg) × (1 − Hct). Typical prescriptions exchange 1.0–1.5 plasma volumes per session: one PV removes ~63 % of intravascular targets, 1.5 PV removes ~75–80 %. Exchange frequency and total sessions are indication-specific.
Replacement Fluids
5 % albumin is the standard replacement solution for plasma exchange unless coagulation-factor replacement is needed, in which case FFP (or solvent-detergent plasma) should be substituted wholly or in part.
5 % albumin — iso-oncotic, pathogen-inactivated; standard fluid for most autoimmune or neurological indications.
Fresh-frozen plasma (FFP) — provides clotting factors and ADAMTS-13; mandatory in TTP or coagulopathy; higher risk of allergic reactions and TRALI.
Crystalloid adjuncts — isotonic saline or Ringer’s lactate may be used in small volumes alongside albumin; never sole replacement for large exchanges.
Heparin Dosing and Contra-indications
Filter-rinse solution — 5 000 IU/L
Initial heparin bolus — 70–80 IU/kg
Continuous infusion — 15–20 IU/kg/h
Contra-indications — heparin-induced thrombocytopenia (HIT), hemoptysis in Goodpasture’s syndrome
Monitoring During TPE
Maintain continuous cardiac monitoring throughout every exchange.
Measure plasma fibrinogen immediately before the session and again on completion — levels typically recover within 48–72 h.
Obtain a platelet count before the first exchange and repeat during multi-session courses to detect procedure-related thrombocytopenia.
Check serum albumin and total protein pre- and post-procedure to identify dilutional hypo-oncotaemia after large-volume exchanges.
When systemic heparin is used, monitor activated partial thromboplastin time (aPTT) during the run and titrate the infusion to 55–75 s (≈1.5–2.5 × control).
If large volumes of plasma or regional citrate are used, measure serum electrolytes — especially ionised calcium — at the end of the exchange and correct hypocalcaemia promptly.
Assess acid–base status with a blood-gas sample whenever substantial plasma volumes or citrate anticoagulation are employed, and correct any significant disturbance.
Complications
Hypotension due to volume shifts or vasoactive-substance removal.
Citrate toxicity → hypocalcaemia, paresthesias, arrhythmias; treat with calcium.
Dilutional coagulopathy after repeated albumin exchanges; monitor fibrinogen.
Allergic or anaphylactoid reactions, primarily with plasma replacement.
Vascular-access problems: bleeding, infection, thrombosis, or pneumothorax.