Dilutional hyponatremia may follow surgery during which large volumes of hypotonic fluid used for irrigation has been absorbed. This was first noticed during transurethral resection of the prostate and was termed the "TUR Syndrome". It also may occur following laparoscopic urologic, orthopedic and gynecologic procedures.


In an adult absorption of 1 liter of fluid may be sufficient to cause hyponatremia. Absorption of fluid up to 2 liters may be tolerated without serious sequelae, while absorption of larger volumes can be fatal, especially with volumes greater than 3 liters (Hahn, 1990).


Features associated with the syndrome:

(1) onset of symptoms and hyponatremia following surgery

(2) large quantity of fluid used during surgery for irrigation, typically hypotonic

(3) significantly less fluid recovered than instilled


Affected patients may show bradycardia, dyspnea, hypotension or hypertension, shock, coma, confusion, visual disturbances, nausea, cardiac arrhythmia, seizures, collapse, or other symptoms (see Hahn, Acta Anaesthesiol Scand, 1991).


Risk factors for the syndrome:

(1) longer procedures with significant bleeding

(2) elevated pressure in the irrigation system (less likely if pressure in the system is kept below the venous pressure according to Hubert et al, 1996)

(3) inexperience of the surgeon

(4) inattention of nursing personnel



(1) monitoring of serum sodium

(2) weight gain following surgery

(3) addition of ethanol to the irrigation solution (1% solution), with monitoring of breath ethanol. The greater the amount of fluid absorbed, the greater the level of ethanol in the expired breath. Absorption of 1 liter of this fluid will give a level of 0.30 mg/mL ethanol in the expired breath.


According to Hahn (1989, pages 147-148; 1991, Figure 4, page 564) when using a 1% ethanol and 1.5% glycine solution:


absorbed fluid in mL =

= 160 + (3210 * (expired breath ethanol in mg/mL during the procedure))


absorbed fluid in mL =

= 700 + (5100 * (expired breath ethanol in mg/mL at 30 minutes after the procedure))


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