Hysteroscopy- telescope that allows inspection of cervical canal and uterine cavity.
Panoramic hysteroscopy is the most common method using a distension media compared to contact hysteroscopy.
Ideal characteristics of a distending medium are:
- Allows clear visualization
- Should be nontoxic, hypoallergenic, non-hemolytic, isoosmalar, rapidly cleared from body
Low viscosity-electrolyte- normal saline or lactated ringer’s solution
They can only be used with bipolar and not monopolar electrocautery.
The electrolyte fluids used for hysteroscopy are isoosmolar and thus do not disturb the osmolar balance between intracellular and extracellular fluid
Electrolyte-poor are: glycine, sorbitol, and mannitol. They can lead to Hyponatremia if large volumes are absorbed.
Automated fluid pump and monitoring system should be used:
- Measure fluid deficit and automated alerts
- Measure and titrate intrauterine pressure
Absorption of large volumes of electrolyte-poor fluid may result in complications:
- Volume overload- acute heart failure, pulmonary edema, dilutional anemia
- Electrolyte plasma imbalance- hyonatremia, hypoosmolality, hyperammonemia, hyperglyciemia
- Neurologic sequelae- slurred speech, visual disturbances, hypersomnia, confusion, seizures
During hysteroscopy absorption is increased when venous sinuses are exposed (myomectomy).
Hyponatremia is particular risk with electrolyte- poor fluids.
Prevention of fluid overload-
- Use isoosmolar electrolyte fluid when possible
- Monitor deficit
- Maintain intrauterine pressure at or to 70-80 mmhg
- Surgical time < 1 hour
Complications occur when deficit between 500-1000 ml and pt has cardiac comorbidities.
At 500ml assess, 100 ml terminate procedure and evaluate patient for hyponatremia.
Also terminate procedure if perforation because fluid can be rapidly absorbed intraperitoneal.
- Halt procedure- if bleeding, insert 30-50 ml foley catheter in uterine cavity and remove 6-8 hours
- Nausea, headache, visual disturbance, prickling, or burning sensation in face and neck, chest pain, SOB.
- Labs- H/H, plts, blood urea nitrogen, creatininine, NA, L, HC03, glucose, and ammonia
- Consider consultation cardiology and nephrology
- Gas embolism can occur when CO2 is the distention media.
Prevention- Keep patient flat or reverse Trendelenburg position
- Avoid use nitrous oxide
- Purge air form tubing prior to insertion uterine cavity
- Maintain intrauterine pressure < 100mm Hg
- Limit re-introduction that may force air or gas into the uterus
- Remove intrauterine gas bubbles ideally with outflow system
Carbon dioxide insuffulated with special instrument hysterosufflator and not laparoscopic insufflators which delivers 1L/min flow which gas embolism.
Dyspnea is the most common symptom
If patient’s end tidal CO2 pressure raises intraoperative suspicion for gas embolism.
Terminate procedure and supportive management vent, vasopressors, volume resuscitation.