Table 3.

Key points for the non-TPE specialists

The organization of the TPE service differs between institutions. In many hospitals, specialist apheresis physicians and nurses provide TPE for ICU patients in close collaboration with intensivists. Since critically ill patients are highly vulnerable and at risk of hemodynamic instability, electrolyte disturbances, and coagulation disorders, close monitoring is needed during TPE. The choice of intravenous access (peripheral or central) should be carefully reviewed. TPE can be performed in the outpatient and inpatient setting. The decision regarding ICU admission rests on the clinical status and not on the need for TPE

The decision to initiate TPE should be based on the rationale that there is a presence of a substance causing a potentially life-threatening disruption that can be removed by TPE or the need for replacing a deficient substance to improve clinical outcomes. It should be evidence-based whenever possible although appropriate trials are lacking in most settings

The following tests must be performed before TPE: ABO Rh blood group and, if appropriate, an RBC antibody screen (in case plasma or RBC priming is needed); ionized calcium, magnesium, and potassium (which may be affected by citrate anticoagulation); complete blood cell count (to determine device settings and to exclude significant cytopenia that may require correction); and coagulation tests (activated partial thromboplastin time, partial thromboplastin time, prothrombin time, and fibrinogen)

The changes in hemostasis and coagulation tests induced by TPE must be considered when interpreting test results and making clinical decisions. For example, instituting oral anticoagulation regimens should be avoided during a string of TPE sessions, since dosing can be challenging given the removal of coagulation factors, combined with the potential addition of coagulation factors (in case of replacement with plasma)

Aside coagulation tests, TPE alters most laboratory variables, including serological tests, and inflammatory markers. Therefore, sample collection must be timed accordingly. Furthermore, circulating biomarkers such as troponin, brain natriuretic peptide, CRP, and LDH are no longer reliable for assessing the disease course

Ideally, repeated TPE requires therapeutic drug monitoring for antibiotics, anticoagulants, and several medications

More is not necessarily better. Standard TPE replaces 1.0 to 1.5 times the TPV. Given removal kinetics, replacing two or three times more does not result in a two- or threefold increase in efficacy

In patients who also require renal replacement therapy (RRT), TPE should be performed first unless there are potentially life-threatening electrolyte disturbances mandating urgent RRT. The volume of replacement fluid given during TPE can be removed during RRT. In addition, fluid shifts that occur following RRT may result in hypotension when blood enters the extracorporeal circuit of the apheresis device during the TPE requiring fluid resuscitation which negates the benefit of volume removal during RRT. Tandem procedures combining TPE and RRT can also be performed in experienced centers

TPE involves replacement with colloids whose oncotic pressure is like the removed plasma. Therefore, in patients with volume overload before TPE, any decrease in the replacement fluid volume will decrease the intravascular volume and potentially cause hypotension. In contrast to dialysis, TPE cannot remove free water, which would lead to hemoconcentration and fluid shifts from the extravascular to the intravascular compartment

TPE has the potential to remove medications and there is limited pharmacokinetic data available. Practical recommendations to address this potential adverse effect include: once daily medications should be administered after TPE, not before; administration of IV medications should be avoided immediately prior to and during TPE; oral medications should be avoided within four hours prior to TPE to allow for adsorption and redistribution prior to the start of the TPE; chimeric antibodies, monoclonal antibodies, and IVIG are effectively removed and timing of administration of these agents and TPE must be coordinated to allow for maximum medication dwell time

In some clinical situations (e.g., Guillain–Barré syndrome), TPE and intravenous immunoglobulins (IVIG) have equivalent efficacy. Combining the two in these scenarios is not recommended and TPE may be reserved in case of failure to IVIG