Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Hysteroscopy: General knowledge overview 4th year Curriculum. Objective Cover basic instrumentation necessary to assemble and operate a hysteroscope Understand the concepts and concerns regarding uterine cavity visualization Uterine access and distention media Understand how to use various energy modalities in operative hysteroscopy Basic hysteroscopic instrumentation. Telescopic Optical Characteristics Field of view is the summation of Degree of field of view of distal lens Angle of lens to central axis of telescope Available fields of view Centered lens = 0o Offset (fore-oblique) expands field to12º, 25º, or 30º Angle of view ALWAYS opposite the light post Field of View Angle of lens to central axis of scope Degree of field of view Orient Post, Then Rotate to Target V P V P P V The angled lens allows you to view lateral structures without angling the scope. All you have to do is rotate the scope-when post (P) is right view (V) is left etc. Hysteroscopic Sheath Continuous Flow Bipartite design: Inner and outer sheaths Independent inflow & outflow channels for distension media Inflow through inner channel (always closet to eye piece) Outflow through outer sheath Able to proactively flush the uterine cavity Maintain a clear field of vision Pre-operative assessment Hysteroscopic cases carry significant and sometimes unique morbidity A thorough H&P is always indicated Often procedures need to be interrupted due to fluid concerns so with operative hysteroscopy subjects should be counseled about staged procedures Uterine Access Preoperative preparation of the cervix Slow, gentle insertion of dilators Pharmacologic-misoprostol Mechanical-laminaria Avoid forceful entry Introduction and advancement of hysteroscope under direct vision Advance only during unobstructed panoramic view How to Dilate the Cervix MUST do bimanual exam first to assess uterine size, version and position KNOW outside diameter of hysteroscopic sheath – take all dilators larger than that diameter OFF THE TABLE DO NOT over-dilate: fluid will leak around scope and lose distention Complications to Hinder Uterine Access Cervical stenosis Acutely flexed uterus Lower segment myoma Intrauterine adhesions Uterine anomaly Distention media Goals Maximize vision Minimize intravasation Create cavity by overcoming myometrial resistance Good inflow and outflow to flush out debris that might impede visualization Provide for a safe procedure Allow for surgeon to effectively operate. Allow electrosurgery to proceed if indicated Factors Influencing Distention Media inflow • Resistance of uterine cavity to distention •Typically requires between 60-70 mmHg to distend cavity • Diameter and patency of inflow channels • Viscosity of distention medium Factors Influencing Distention Media Outflow • Leakage at cervix •Scope should fit snugly into cervix • Rate of outflow •Can adjust or restrict outflow channel • Peri-transtubal extravasation • Intravasation of distention media into tissue •This is where morbidity can occur Ways to decrease intravasation • Intrauterine Pressure Ideally 75 mmHg •Use automated devices that provide fixed pressure/variable flow rates for fluid delivery •Increased when intrauterine pressure of distending media is greater then patients mean arterial pressure (MAP) • Be constantly aware of fluid deficit during surgery that is prolonged or opens large vascular channels •Resection of myoma, Endomymoetrial resection, etc. It is the surgeons responsibility to constantly monitor fluid deficits prevent excessive intravasation. Fluid deficit of 750cc (Nonelectrolyte) or 1500 (normal saline) should signal the impending need to complete the case For deficits of 1500cc of non-electrolyte or 2500 cc normal saline Conclude case Assess electrolytes Manage complications Common Distention media Low Viscosity Electrolyte-Containing Solution for Use With Bipolar Electrosurgery 0.9% sodium chloride Non-Electrolyte, Non-Conductive Solutions for Monopolar Resectoscopic Surgery 3% Sorbitol,1.5% Glycine, 5% Mannitol Absorption of Non-Electrolyte Medium Morbidity and Mortality Hypo-osmolality Hyponatremia Cerebral edema Cardiac Neuromuscular Brain stem herniation Death What is Electrosurgery? Application of high frequency alternating current (AC) Creating secondary thermal tissue effects Electrosurgical Outputs - Waveforms Variations of current & voltage in relation to time The Effects of Peak Voltage on Thermal Spread during Electrosurgery Deep penetration Minimal spread Superficial penetration Wide spread Conventional Monopolar Electrosurgery requires non-conductive media and adequate current density If the fluid is non-ionic then electrical current cannot flow, so it arcs to the tissue that has ionic components and less resistance allowing the current to flow. Current flows through the tissue Non-conductive media Ω = ∞ Tissue Impedance = 100 Ω Tissue Conventional Monopolar Electrosurgery - In Normal Saline If the solution is ionic then the electrical current disperses throughout the solution and doesn't concentrate at the tissue. Saline Impedance = 25 Tissue Impedance = 100 Tissue Current flows through saline following path of least resistance to return electrode Summary A Surgeon should know basic hysteroscopic instrumentation and assembly prior to surgery Understanding how distention media should be used and monitored will allow for safe hysteroscopic procedures Understanding the basics of electrosurgery will avoid problems in the OR