A patient is planned to undergo hysteroscopic polypectomy using bipolar electrocautery. What is the ideal agent for distention ?

Correct Answer: D. Normal saline

Normal saline is the ideal distention medium for bipolar electrocautery in hysteroscopic procedures because it is electrically conductive, allowing current to flow safely through the bipolar circuit while maintaining hemostasis. Unlike monopolar systems that require non-conductive media, bipolar electrocautery operates with both active and return electrodes on the instrument itself, creating a closed circuit within the uterine cavity. Normal saline's isotonicity prevents fluid overload syndrome, maintains endometrial visibility, and poses minimal risk of hyperammonemia or hyponatremia—complications seen with hypotonic media. In Indian gynecological practice, normal saline remains the gold standard for bipolar hysteroscopic procedures (polypectomy, myomectomy, septum resection) as per FOGSI guidelines. The medium must be sterile, isotonic, and electrically conductive to permit safe bipolar current delivery while avoiding the systemic complications associated with other media. This is the only option that satisfies all three criteria simultaneously.

Why the other options are wrong

A. Glycine — Glycine is a non-conductive hypotonic medium used exclusively for monopolar electrocautery, not bipolar. Although it prevents electrical complications in monopolar circuits, it is contraindicated for bipolar procedures and carries risk of hyperammonemia, transient blindness, and encephalopathy if absorbed systemically—a significant concern in Indian practice where fluid overload is not uncommon. B. 70% dextrose — Dextrose solutions are non-conductive and hyperosmolar, designed for monopolar electrocautery to prevent fluid absorption complications. However, they are unsuitable for bipolar systems because they do not conduct electrical current, preventing proper electrocautery function. Additionally, hyperglycemia and osmotic diuresis are potential systemic effects, making it inappropriate for routine hysteroscopic polypectomy. C. CO2 — CO2 is a gas distention medium used only for diagnostic hysteroscopy or brief operative procedures in monopolar systems, never for bipolar electrocautery. It provides poor visibility due to fogging, carries risk of gas embolism (potentially fatal), and does not conduct electrical current. CO2 is contraindicated when hemostasis via electrocautery is required, as in polypectomy.

High-Yield Facts

Mnemonics

BIPOLAR = SALINE (Conductive) BIpolar = Isotonic SAline (conductive). MONOpolar = NON-conductive (glycine/dextrose). Remember: bipolar circuit is closed (needs conduction), monopolar is open (needs insulation). SAFE Distention for Bipolar Saline (isotonic, conductive) | Avoid glycine/dextrose (monopolar only) | Fluid overload prevented | Electrocautery hemostasis enabled.

NBE Trap

NBE pairs "hysteroscopic polypectomy" with glycine to trap students who memorize glycine as a universal hysteroscopic medium without distinguishing monopolar (glycine) from bipolar (saline) electrocautery systems. The key discriminator is the type of electrocautery, not just the procedure name.

Clinical Pearl

In Indian tertiary centers, bipolar hysteroscopic systems are increasingly preferred over monopolar because they allow normal saline use, eliminating the risk of hyperammonemia and TURP syndrome—complications that increase morbidity in resource-limited settings where post-operative monitoring may be suboptimal. Always confirm the electrocautery type before selecting distention media.

_Reference: DC Dutta's Textbook of Gynaecology (7th ed.), Ch. 14 (Hysteroscopy); FOGSI Guidelines on Hysteroscopic Surgery (2019)_