Myometrial Injection of Vasopressin Verna Thomas, BSN, SRNA

Objectives Familiarize learner with myomectomy procedure and management options Describe anesthetic considerations for myomectomy Identify purpose for use of vasopressin and mechanism of action Recognize potential complications associated with use of vasopressin Engage the learner in a spirited discussion regarding a case of myometrial vasopressin injection

Case of Interest 29 y/o AA Female, 67 kg ASA 2, MP II Employed RN History of uterine fibroid, syncope at work, received cardiac work-up, anemic Robotic Assisted Laparoscopic Myomectomy

Myomectomy Define Prevalence Rationale Population most common benign tumor of the uterus in women of reproductive age Prevalence clinically diagnosed in 25% of women with a predicted incidence of 75% Rationale myomectomy versus hysterectomy to preserve fertility Population predominance amongst African American women of child-bearing age to ~ 50y

Management Options Uterine Artery Embolization

Management Options Laparoscopic Assisted Abdominal Myomectomy (LAAM) Laparoscopic Myomectomy (Standard)

Robot Assisted

Anesthesia Considerations Bleeding Hemodynamic Alteration Respiratory Compromise Positioning

Myoma Blood Supply

Case Update #1 Standard Induction Trocars/Insufflation Vasopressin Injection Re-insufflation

Traditional Use

Endogenous Synthesis

Effects V1 vascular receptors mediate vasoconstriction and are located on vascular smooth muscle. V1 receptors are found in the kidney, myometrium, bladder, hepatocytes, platelets, adipocytes and spleen. These G-protein coupled receptors activate phospholipase-C via Gq G-protein, which ultimately leads to an increase in intracellular calcium. V2 receptors are predominantly located in the distal tubule and collecting ducts of the kidney. These G-protein coupled receptors activate adenyl cyclase to increase cyclic adenosine monophosphate. This mobilizes aquaporin channels, which are inserted into the apical membrane of the renal collecting duct cells and endothelial cells. V2 receptors are responsible for antidiuretic effects of vasopressin. Their presence on endothelial cells induces the release of Von Willebrand Factor (VWF) and Factor VII: Coagulant (FVII: c). VWF protects FVII from breakdown in plasma and is important in binding platelets to the site of bleeding. V3 receptors are found mainly in the pituitary. They are Gq-coupled G-protein receptors, which increase intracellular calcium when activated. They are thought to be involved in adrenocorticotropic hormone release, responsible for the actions of vasopressin on the central nervous system, and may act as a neurotransmitter or mediator involved with memory consolidation or retrieval and body temperature regulation Severe skin necrosis after extravasation of low-dose vasopressin administered for catecholamine resistant shock has been reported and peripheral administration of low-dose vasopressin infusions should be discouraged.[31] It is thrombogenic, acting via V2 receptors. Anaphylaxis, bronchospasm, urticaria and ischemia of the gastrointestinal tract have been reported with clinical use. Reduction in cardiac output and systemic oxygen delivery, impairment in gut mucosal and hepatic oxygenation, increases in aminotransferases activities and bilirubin concentrations and reduction in platelet count have also been observed. In addition, sodium concentration and plasma osmolality should be regularly evaluated, although to date there is no evidence that vasopressin analogs are linked to antidiuresis, water retention or renal impairment in septic shock patients. Conversely, several studies reported an improvement in renal function as well as advantages over sole catecholamine therapy in patients at risk for acute renal failure.

Synthetic Vasopressin in Myomectomy Control bleeding Potent vasoconstrictor 20U/ml diluted in 100-200ml of NSS Max injection 3-5U Anesthesia should be notified before injection Aspirate before injection 15-25 min half-life

Medical Templates 2003 Template 8 20 units in 200ml NS Max 3-5 units Exogenous vasopressin (8 arginine vasopressin) is presented as sterile aqueous solution of synthetic vasopressin for intravenous, intramuscular and subcutaneous administration. It is not protein-bound and has a volume of distribution of 140 ml/kg. The plasma half-life of vasopressin is 24 minute. It is cleared by renal elimination (65%) and metabolism (35%) by tissue peptidase. Cost is an issue, which might have limitations into ongoing studies on the use of vasopressin as an alternative to adrenaline as 1 ampoule (20 U) of vasopressin costs almost 70 times more than 1 ampoule of adrenaline.  20 units in 200ml NS Max 3-5 units

Case Update #2 Robotic Assisted Laparoscopic Myomectomy Approximately 45-60 min into the case Incision through serosa BP cuff cycling every 3 minutes

Series of Unfortunate Events

Differential Diagnosis Venous Air Embolism (VAE) Subatmospheric pressure w/i an open vein Decreased EtCO2, desaturation, sudden hypotension TEE, precordial Doppler sonography Pulmonary Embolus Entry of blood clots, fat, tumor cells, air, amniotic fluid, or foreign material into venous system sudden cardiovascular collapse, hypoxemia, bronchospasm, decreased ETCO2, elevated CVP and PAP TEE; may not reveal the embolus but will show R. heart distension and dysfunction MI No preoperative comorbidities HoTN, bradycardia, no detectable ECG changes TEE; more sensitive indicator of MI than ECG Hemorrhage

Transesophageal Echocardiogram Akinesis Left ventricular akinesis is usually due to coronary artery disease which can affect the many walls of the heart. When coronary artery blood flow is reduced due to atherosclerotic plaque, the ability for the myocardium to function is diminished. In this example, look for the left ventricle to appear dyskinetic and reduces the ejection fraction but also changes in chamber size and function are evident. *

Transesophageal Echocardiogram Normal *

Case Update #3 Weak/thready carotid pulse Absent radial pulses PEA w/ACLS Central line placement Swan ganz placement Milrinone and Epinepherine infusion Pulmonary Edema Lasix Refractory hypoxemia

Case Conclusion Prepped for ECMO Heparinized Near Complete Resolution Balloon Pump Following Commands Pressors and balloon pump discontinued Discharged from hospital POD 8

What Did We Learn Vigilance Never deviate from standard of care Treated the BP Notified the surgeon and called for help Rapid assessment and treatment/supportive care

Questions/Comments