Contrast Dye Used in Hysterosalpingography (HSG)

1. Water-soluble (water-based) contrast

• The more commonly used type today.
• Provides better mucosal/architectural detail of the uterine cavity and the ampullary portion of the tubes, and is cleared from the body more quickly than oil-based agents.
• Examples of iodinated agents used include compounds like iohexol.

2. Oil-based contrast

• Historically used and still used in some centers/protocols.
• Associated with less postprocedural vaginal bleeding.
• Notably, a large multicenter RCT (n=1,119) found a significantly higher live birth rate with oil-based contrast compared to water-based (38% vs 28%; RR 1.38, 95% CI 1.17-1.64), an effect thought related to a "flushing" therapeutic action (dislodging mucus plugs/debris) and possibly improved endometrial receptivity - Berek & Novak's Gynecology, p. 2058.
• Theoretical risk of oil embolism from vascular intravasation exists, but this has not been observed as a real complication in large prospective studies - Berek & Novak's Gynecology, p. 2059.

Practical/procedural notes

• Contrast is injected slowly (1-3 mL initially shows intrauterine detail; larger volumes can obscure small polyps/adhesions). Injection continues until the tubes fill, then until bilateral intraperitoneal spill is seen - Pfenninger and Fowler's Procedures for Primary Care.
• Warming the contrast before injection may reduce cramping.
• Iodine allergy screening is required beforehand; patients with a known iodine/contrast allergy should be pretreated with glucocorticoids.
• HSG (and its contrast) is contraindicated in pregnancy and in active/suspected pelvic infection or known hydrosalpinx (risk of post-procedure PID, which can exceed 10% in hydrosalpinx).
• Other rare risks: vascular intravasation, uterine perforation, cervical laceration, vasovagal reactions, and allergic reaction to the contrast dye itself.

Recent evidence check

Indications and Contraindications of HSG (Hysterosalpingography)

Indications

• Primary indication: female infertility workup - to assess tubal patency and uterine cavity contour, since tubal factors account for ~25-35% and uterine factors ~16% of infertility cases.
• Evaluation of patients with risk factors for tubal disease: history of chlamydial infection, pelvic inflammatory disease (PID), endometriosis, or prior extensive pelvic surgery.
• Detection of intrauterine pathology: submucosal leiomyomas (fibroids), endometrial polyps, intrauterine synechiae (Asherman syndrome), and Mullerian anomalies (e.g., septate/bicornuate uterus).
• Confirmation of tubal occlusion after tubal ligation (sterilization confirmation).
• Can have a therapeutic role - flushing mucus plugs/debris from the tubes, which may itself improve fertility (especially with oil-based contrast) - Berek & Novak's Gynecology, p. 2058.

Contraindications

• Pregnancy (known or suspected) - absolute contraindication due to risk to the fetus from an intrauterine procedure and radiation exposure. A urine pregnancy test is typically done first.
• Active or suspected pelvic infection / PID - risk of exacerbating infection; HSG is also avoided in known hydrosalpinx, where post-procedure PID risk exceeds 10%.
• Active uterine bleeding - obscures visualization; timing HSG in the first ~7-10 days of the cycle (after menses, before ovulation) avoids this and takes advantage of a thin proliferative endometrium.
• Known severe allergy to iodinated contrast - relative contraindication; patients with prior severe contrast reactions should be pretreated with glucocorticoids/antihistamines or an alternative study considered.
• Recent pelvic surgery or trauma, recent uterine instrumentation, and (per some sources) uncontrolled hyperthyroidism are also cited as relative contraindications.
• Grainger & Allison's Diagnostic Radiology, p. 886
• Berek & Novak's Gynecology, p. 2058-2059
• Pfenninger and Fowler's Procedures for Primary Care

Associated complications (relevant to risk-benefit/contraindication discussion)

Crash Cart Drugs (Code Cart Medications)

Core cardiac arrest drugs (ACLS)

• Epinephrine 1:10,000 (pre-filled syringe) - first-line vasopressor in all arrest rhythms (VF/VT, PEA, asystole)
• Amiodarone 150 mg vial - antiarrhythmic for refractory VF/pulseless VT
• Lidocaine 100 mg/5 mL (pre-filled syringe) - alternative antiarrhythmic if amiodarone unavailable
• Atropine 1 mg (pre-filled syringe) - symptomatic bradycardia (removed from asystole/PEA algorithm since 2010 guidelines)
• Vasopressin - historically used as epinephrine alternative (largely removed from current algorithms)
• Adenosine 6 mg - rapid termination of stable narrow-complex SVT
• Magnesium sulfate - torsades de pointes, refractory VF
• Calcium chloride - hyperkalemia, hypocalcemia, calcium channel blocker toxicity
• Sodium bicarbonate - severe acidosis, tricyclic overdose, hyperkalemia
• Dopamine - symptomatic bradycardia/hypotension unresponsive to atropine

Other drawer contents (by purpose)

• Allergy/anaphylaxis: Epinephrine (EpiPen/EpiPen Jr), diphenhydramine (Benadryl) 50 mg, methylprednisolone (Solu-Medrol) 125 mg
• Reversal agents: Naloxone (Narcan) for opioid overdose; flumazenil for benzodiazepine reversal
• Glucose/metabolic: Dextrose 50% (D25 for pediatrics) for hypoglycemia
• Cardiac ischemia/ACS: Aspirin 81 mg (chewable), nitroglycerin (spray or 0.4 mg SL tablets), morphine
• Rate/rhythm control: Diltiazem (Cardizem), metoprolol (Lopressor), verapamil, procainamide, digoxin
• Sedation-related emergencies: Reversal agents plus advanced airway equipment and a functional defibrillator, since sedation complications are a common trigger for crash cart use - Yamada's Textbook of Gastroenterology, p. 1858
• IV fluids: Normal saline, lactated Ringer's, D5W, with tubing and IV/IO access supplies
• Airway/equipment: Bag-valve mask, oral/nasal airways, Magill forceps, oxygen supplies, defibrillator/AED, suction device, intubation equipment

Specialty considerations

• In procedural settings (endoscopy, dermatology/office procedures, urology with local anesthetic use), the crash cart must include lipid emulsion for local anesthetic systemic toxicity (LAST) - Hinman's Atlas of Urologic Surgery.
• Regulatory/accreditation standards require an emergency crash cart to be immediately available wherever sedation or procedures with cardiopulmonary risk are performed - Cummings Otolaryngology; Clinical Gastrointestinal Endoscopy.
• Functional equipment checks matter as much as drug stocking - documented malpractice cases have hinged on crash carts with non-functioning suction devices - Brogdon's Forensic Radiology.