Forced diuresis

Synonyms

Toxin elimination; elimination process;

Definition

Forced diuresis is the increase in excretion of toxic substances that are eliminated renally by a drug-induced increase in urine volume (Marx 2015).

Implementation

After insertion of a bladder catheter, various forms of forced diuresis can be used:

• 1. loop diuretics:

The patient receives every 4 hours:

- 1 l NaCl 0.9 % for hyperhydration

plus

- 40 mg furosemide (Herold 2022), Kasper (2015) recommends 20 - 80 mg i. v. in increasing dosage.

This is done under constant control of diuresis and water or electrolyte balance (Herold 2022).

• 2. mannitol:

In another form of forced diuresis, the patient receives mannitol, an osmotically active diuretic. Mannitol is infused 0.25 - 1 g / kg i. v. over 20 min, and this is repeated every 4 - 6 h. The advantage of mannitol administration is a non-acidic urine (Klauwer 2013).

• RenalGuard System:

The RenalGuard system achieves a high urine output with simultaneous euvolemia.

Here, urine is collected in a bag that is suspended from a digital scale. The scale, in turn, is connected to a high-volume fluid pump. Every drop of urine that enters the bag is replaced with NaCl by the fluid pump.

Initially, a small fluid bolus of about 3 ml / kg bw is infused, and diuresis is initiated with low doses of furosemide (0.25 mg / kg bw). As a result, urine output increases to 500 - 600 ml / min in about 60 min and can usually be maintained for 6 h without additional diuretic administration (Solomon 2014).

Pharmacodynamics

- Contrast Agent:

Forced diuresis accelerates tubule passage, thereby shortening the contact time of the contrast agent (Latus 2020).

- Loop diuretics:

Loop diuretics decrease tubular reabsorption (Michels 2010).

- Mannitol:

Mannitol is one of the osmotically active diuretics. These are glomerularly filtered but not reabsorbed in the tubules. This allows water to be osmotically bound in the tubule. Na+- excretion is low in this case (Freissmuth 2012).

In addition, mannitol can bind water intravascularly, which is required, for example, to decongest cerebral edema (Dellas 2018).

- Increase in diuresis:

If there is a pH-dependent dissociation in the elimination of toxins, acidification or alkalinization of the urine can further increase the effectiveness of diuresis (Füllgraff 2007).

Indication

Loop diuretics:

- To prevent contrast-induced kidney injury (AKI) caused by iodine-containing contrast media used in, for example, cardiac catheterization, computed tomography, etc.. Forced diuresis should begin at least 12 h before the examination and end no earlier than 12 h after the examination (Latus 2020).

- For flushing out ureteral stones (Wilhelm 2017).

- Hypercalcemia (indicated exclusively for mild hypercalcemia, as the effect is small [Kasper 2015]).

Indications for forced diuresis for secondary toxin elimination are severe intoxications with toxins to be excreted renally such as:

- Barbiturates, phenobarbital

- lithium

- salicylates such as ASS

- Thallium (Herold 2022)

mannitol:

- During chemotherapy with e.g. cisplatin, to avoid kidney damage (Kasper 2015)

- in case of poisoning (Freismuth 2012)

- In patients with e.g. arterial hypertension and pre-existing renal damage etc. (Crona 2017).

Mannitol is also used for emergency treatment of

- acute glaucoma

- acute cerebral edema (Freissmuth 2012), as it can bind water intravascularly (Dellas 2018).

RenalGuard System:

This is primarily used to prevent renal damage from iodine-containing contrast administration (Solomon 2014). It attenuates contrast-induced nephropathies (CIN) from 18% (with forced diuresis with NaCl and furosemide, see above) to 4.6% (Latus 2020) according to the MYTHOS- study from 2012 (Marenzi 2012).

Adverse effects

Loop diuretics:

There is a risk of disturbance of water, electrolyte, base, and acid balance (Herold 2022).

Mannitol:

- Volume expansion

- Hyponatremia

- Hypoosmolarity

- Headache

- Dizziness

- nausea / vomiting

- Cardiac decompensation with volume expansion (Freissmuth 2012

Contraindication

NaCl:

- heart failure

- renal insufficiency

- seizure disorder

- Shock state (Herold 2022)

Mannitol:

- myocardial insufficiency

- pulmonary edema

- Anuria (Dellas 2018)

1. Crona D J, Faso A, Nishijima T F, McGraw K A, Galsky M D, Milowsky M I (2017) A Systematic Review of Strategies to Prevent Cisplatin-Induced Nephrotoxicity. The Oncologist 22 (5) 609 - 619
2. Dellas C (2018) Last minute pharmacology. Elsevier Urban and Fischer Publishers Munich 55
3. Freissmuth M, Offermanns S, Böhm S (2012) Pharmacology and toxicology: from molecular basis to pharmacotherapy. Springer Verlag Berlin / Heidelberg 368
4. Füllgraff G, Brune K, Palm D (2007) Pharmacotherapy: clinical pharmacology. Springer Verlag Berlin / Heidelberg 525
5. Herold G et al (2022) Internal medicine. Herold Publishers 940
6. Kasper D L, Fauci A S, Hauser S L, Longo D L, Jameson J L, Loscalzo J et al (2015) Harrison's Principles of Internal Medicine. Mc Graw Hill Education 102e- 12, 610, 1809, 2480, 2481, 472e- 3.
7. Klauwer D, Neuhäuser C, Thul J, Zimmermann R (2013) Pediatric intensive care pediatric cardiology practice. Deutscher Ärzteverlag GmbH 105
8. Latus J, Schwenger V, Schlieper G, Reinecke H, Hoyer J, Persson P B, Remppis B A, Mahfoud F (2020) Contrast-induced acute kidney injury-consensus paper of the working group "Heart - Kidney" of the German Society of Cardiology - Cardiovascular Research e. V. and the German Society of Nephrology e. V. Der Kardiologe (14) 494 - 504.
9. Marenzi G, Ferrari C, Marana I, Assanelli E, De Metrio M, Teruzzi G, Veglia F, Fabbiocchi F, Montorsi P, Bartorelli A L (2012) Prevention of Contrast Nephropathy by Furosemide With Matched Hydration: The MYTHOS (Induced Diuresis With Matched Hydration Compared to Standard Hydration for Contrast Induced Nephropathy Prevention) Trial. JACC: Cardiovascular Interventions 5 (1) 90 - 97
10. Marx G, Muhl E, Zacharowski K, Zeuzem S (2015) Critical care medicine. Springer Verlag Berlin 1319
11. Michels G, Kochanek M (2010) Repetitorium of internal intensive care medicine. Springer Verlag Berlin / Heidelberg 105
12. Solomon R (2014) Forced diuresis with the RenalGuard system: impact on contrast-induced acute kidney injury. J Cardiol. 63 (1) 9 - 13
13. Wilhelm K (2017) Forced diuresis for acute ureteric colic. Urologist A. 56 (11) 1461 - 1464