1. Vasopressors Rasha Sarhan, MSC, B.Sc.Pharm, Pharm D Candidate
4. Objectives Define shock. Define and interpret various hemodynamic parameters [mean arterial pressure (MAP), preload, afterload, Cardiac output (CO)]. List types, causes, and symptoms of shock. Describe the pharmacology, doses and use of vasopressors. Explain practical issues with using vasopressors. Apply knowledge to a patient with a shock syndrome
5. Shock A state of cellular and tissue hypoxia due to reduced oxygen delivery and/or increased oxygen consumption or inadequate oxygen utilization. SBP < 90 mmHg or reduction of > 40 mmHg with perfusion abnormalities* despite adequate fluid resuscitation. * End organ hypoperfusion (lactic acidosis, oliguria, mental status deterioration).
6. Preload (PCWP) Represents the amount of blood available to the left ventricle for pumping and is influenced by venous return to the left atrium. Normal = 12 - 18 mmHg Dry < 12 mmHg Wet > 18 mmHg
7. Afterload (SVR) Represents the ventricular wall tension required for expulsion of ventricular blood volume into the aorta during contraction. Normal = 1000 - 1600 dynes-sec/m2 Arterial dilation < 800 dynes-sec/m2 Arterial constriction > 1800 dynes-sec/m2
8. Definitions MAP = 1/3 SBP + 2/3 DBP MAP = CO X SVR CO = HR X SV The stroke volume is determined by: Preload Afterload Myocardial contractility SVR is determined by: Vessel length Blood viscosity Vessel tone
12. Hypovolemic Shock Goal is to increase preload (PCWP) by replacing fluid loss with blood, crystalloid, or colloid.
13. Cardiogenic Shock Goal is to increase cardiac output (CO) with inotropic pharmacotherapy (dobutamine) and reduce afterload (SVR) with vasodilators.
14. Septic Shock Goal is to increase preload (PCWP) with fluid replacement (crystalloid, then colloid), then increase afterload (SVR) with vasopressor (e.g. dopamine, norepinephrine, phenylephrine, vasopressin).
15. Neurogenic Shock Goal is to increase afterload (SVR) with vasopressor (e.g. phenylephrine, norepinephrine).
16. Combined Shock Patients with pancreatitis or sepsis have distributive shock but may have hypovolemic and cardiogenic component. Patients with cardiomyopathy may present with cardiogenic shock and hypovolemic shock. Patients with severe traumatic injury may have hemorrhagic and distributive shock Patients with spinal cord injury can have distributive and cardiogenic shock.
17. Vasopressors Goals of Therapy PCWP = 8 to 12 mm Hg ( up to 15 mm Hg in specific patients). MAP 65 mm Hg. Mixed venous Oxygen saturation (SvO2) 65%. Central venous Oxygen saturation (ScvO2) 70%. Lactate Clearance 20%.
19. Dopamine (Dop) Receptors: D1, D2, 1, 1 * Use: At (3 to 10 mcg / Kg/ min), increases CO in cardiogenic shock. At (10 to 20 mcg / Kg/ min), increases afterload (SVR) and urine output in septic shock. Dose: 1 to 20 mcg / kg/ min. Monitoring: Blood pressure (BP); Heart rate (HR); urine output, renal function, serum glucose, CO, PCWP, and SVR.
20. Dobutamine (Dob) Receptors: 1, 2, 1 Use: Increase CO and decrease afterload in cardiogenic shock. Dose: 1 to 20 mcg / kg/ min. Monitoring: BP, ECG, renal function, urine output, CO, PCWP, and SVR.
21. Norepinephrine (Nepi) Receptors: 1, 1, 2 Use: Increase afterload (SVR) in septic and neurogenic shock. Dose: 8 to 20 mcg / min. Monitoring: BP, HR, CO, urine output, infusion site for extravasation or necrosis.
22. Epinephrine (Epi) Receptors: 1, 1, 2 Use: Increase afterload (SVR) in neurogenic shock or as an add on in septic shock. Dose: 1 to 10 mcg / min. Monitoring: BP, HR, continuous cardiac monitoring, serum lactate, site of infusion for blanching/extravasation.
23. Phenylephrine (Phen) Receptors: 1 Use: Increase afterload (SVR) in neurogenic shock, or as salvage - add on - to other vasopressors. Dose: 100 to 180 mcg / min. Monitoring: BP, HR, CO, local skin blanching, extravasation.
24. Vasopressin (Vas) Depleted in septic shock Receptors: 1. Vascular V1 receptors: Cause vasoconstriction. 2. Renal V1 and V2 receptors: Increases GFR and net increase urine output. 3. Pituitary gland V3: Increase serum cortisol. Dose: 0.02 to 0.04 units / min. Monitoring: Fluid input, urine output, HR, BP, skin blanching.
25. Vasopressors Pharmacology Dop Dob Nepi Epi Phen Vas 1 0 1 0 0 2 0 0 0 D1,D2 0 0 0 0 0 V1, V2 0 0 0 0 0 Dose 1 to 20 mcg/kg/min 1 to 20 mcg/kg/min 8 to 20 mcg/mi n 1 to 10 mcg/min 100 to 180 mcg/min 0.02 to 0.04 units/min
26. Vasopressor IV Infusion Chart Medication Indication Bolus Initial IV infusion Titration Usual dose Maximum dose / duration Diluent / Line Dobutamine Decreased cardiac output No Bolus 0.5 to 1 mcg / Kg / min By 2.5 mcg / kg /min According to response ~ every 5 min 2 to 20 mcg / kg /min Up to 40 mcg / Kg / min NS / D5W / LR Do Not add Sod Bicarbonate Peripheral Dobutamine Post cardiac Arrest ACLS 5 to 10 mcg /Kg / min 0.5 to 1 mcg / Kg / min 2 to 20 mcg / kg /min Dopamine Cardiogenic/septic Shock, CHF/ renal failure No Bolus 2 to 5 mcg/kg/min 5 to 10 mcg/kg/min increments Up to 20 - 50 mcg / kg /min NS / D5W Do Not add Sod Bicarbonate Central Line Epinephrine3 Hypotension / Septic Shock or as an add on to other vasopressors No Bolus 0.1 to 0.5 mcg / Kg /min 0.05 to 0.2 mcg/kg/minute every 10- 15 min to target MAP 1 to 10 mcg / min Up to 10 mcg / min NS / D5W Central Line Epinephrine Asystole/ pulseless arrest ACLS 1 mg IV or I.O. Give 1 mg every 3 to 5 min until return of spontaneous circulation. Up to 0.2 mg / Kg (total dose) In BB and CCB overdose NS / D5W/ LR Central Line*2.5 mg endotracheal Dilute in 5 to 10 ml NS or sterile water Epinephrine Anaphylaxis o mg IV over 5 min 5 to 15 mcg / min Norepinephrine4 Levophed Hypotension / Shock No Bolus 8 to 12 mcg /min Titrate to desired response by 2 mcg / min 1 to 4 mcg /min Up to 20 mcg / min NS / D5W Central Line
27. Summary Types of Shocks: hypovolemic, Cardiogenic, Septic, neurogenic. Hypovolemic Shock: goal is to increase preload with fluids1st. Cardiogenic Shock: goal is to increase cardiac output (CI) with dopamine (1-10g /Kg/min), or dobutamine. Septic Shock: goal is to increase preload with fluids1st , then increase afterload with, dopamine, norepinephrine, phenylephrine, or vasopressin. Neurogenic Shock: goal is to increase afterload with norepinephrine, phenylephrine.
28. Summary Nepi is the initial vasopressor, 8 to 20 g / min. Dop alternative to Nepi in patients with low CO or HR. Dop receptor effect is dose dependent, 1 to 20 g / kg / min. Dob used in patients with cardiogenic shock 1 to 20 g / kg / min. Epi used as an add on to increase MAP, 1 to 10 g / min. Vasopressin used as an add on to Nepi to increase MAP, 0.03 Unit / min. Phen used in neurogenic shock or as an add on to increase MAP, 100-180 g / min.