Hysteroscopic surgery is widely used for the treatment of gynecological diseases, such as septum, synechiae, polyp and intrauterine fibroids. The complication rate is estimated as 0.22% and includes uterine perforation, massive bleeding, and fluid overload. Operative hysteroscopy intravascular absorption (OHIA) syndrome refers to fluid overload complications from operative hysteroscopies and is considered a major complication. Report describing the clinical association between irrigation fluid temperature to intravasation rate itself or the risk of fluid overload are limited mainly to theoretical models. Due to the aforementioned, we aim to evaluated the role of temperature on absorption of the irrigation solution in hysteroscopic surgery.

Hysteroscopic surgery is widely used for the treatment of gynecological diseases, such as septum, synechiae, polyp and intrauterine fibroids. Advantages include less invasiveness and faster recovery compared to traditional laparotomy. The complication rate is estimated as 0.22% and includes uterine perforation, massive bleeding, and fluid overload.

Operative hysteroscopy intravascular absorption (OHIA) syndrome refers to fluid overload complications from operative hysteroscopies and is considered a major complication. Although rare, large-scale fluid absorption might lead to symptoms severe enough to require intensive care including dilutional hyponatremia, hypoosmolality, brain oedema, hypokinetic circulation and cardiovascular collapse.

During surgical resection, hydrostatic pressure is usually higher than intravascular pressures, mainly in the venous bed, allowing intravasation of irrigation solution from the surgical field to the intravascular space. The greater the difference between these hydrostatic pressures, the higher the flow rate into the blood and the higher the risk of fluid overload. Moreover, although it is important to control surgical time and to keep distension pressure as low as possible, fluid overload may occur before the predicted period.

Preventive measures, such as low-pressure irrigation, might reduce the extent of fluid absorption but does not eliminate this complication. Monitoring the extent of absorption during surgery allows control of the fluid balance in the individual patient.

Report describing the clinical association between irrigation fluid temperature to intravasation rate itself or the risk of fluid overload are limited mainly to theoretical models. Benefits of cold irrigation fluids are reported in studies on transurethral prostatic resection (TUR) and include shorter procedure duration, improved surgical visualization, less fluid use and reduced blood loss. The results of studies demonstrating higher complication rate with hypothermia caused by locally applied cold irrigation solutions are equivocal and were not demonstrated specifically in hysteroscopic procedures.

The application of warm distension fluid has been recently used in office hysteroscopy in order to reduce pain severity. A recent meta-analysis including 5 randomized control trials reported warm saline was linked to a significant reduction in the visual analog scale (VAS) pain score during the procedure and higher patient satisfaction rate. Nevertheless, warm irrigation solution might be limiting for longer procedures due to expected expansion of the vascular system resulting higher fluid deficit in shorter time.

Due to the aforementioned, we aim to evaluated the role of temperature on absorption of the irrigation solution in hysteroscopic surgery.

Material and Methods This is a prospective study that will be conducted at a single tertiary medical center. Study population will include all women undergoing hysteroscopic surgery due to benign indication. Women with known malignancy or hysteroscopic procedures using alternative solutions (Ringer's lactate, 1.5% glycine, 5% dextrose) will be excluded from the study.

A TruClear™ hysteroscope will be used with 0.9% saline solution as the expanding media. Three different temperatures will be randomly assigned to each case including: room temperature (24°C), and body temperature (37°C). The distension fluid will be prepared in advance using heating incubator for both solutions temperatures. The liquid temperatures will be confirmed by thermometer before the procedure. Randomization to each arm will be made using computer randomizer. The time to reach fluid deficit will be measured at the following deficit points: 100cc,150cc, 250 cc, 500 cc, 750 cc, 1000cc, 1500 cc and total deficit. In addition, presurgical and post-surgical blood samples for sodium level and osmolality will be collected. Immediate post-surgical pain will be assesses 1 hour following the procedure using the visual analog scale.

Demographic and clinical characteristics will be drawn from women's medical files. Operative and post-operative data will be collected including: operation indication, operation duration, operation complications (uterine perforation, bleeding, fluid overload complications- electrolyte disturbances, osmolality, pulmonary embolism, pulmonary oedema), post-operative complications (hemorrhage, endometritis, vascular - thromboembolic event, ileus).

Inclusion criteria:

- All women undergoing gynecologic hysteroscopic surgery.

Exclusion criteria:

• Women with known malignancy
• hysteroscopic procedures using alternative solutions (Ringer's lactate, 1.5% glycine, 5% dextrose)

Hysteroscopy is performed only in women with uterus