Inotropes and vasopressors a .pptx

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1. Inotropes and vasopressors By Melaku Tsediew (ECCM R3) Moderator :Dr. Tigist Bacha( MD,MPH,associate prof. of pediatrics PCCM) 7/07/14

2. Objectives To discuss inotropes and vasopressors

3. Outlines Introduction Indication and contraindication Inopressor choice in pediatrics PPV/PEEP as inotropes Titration principles Weaning of inotropes and vasopressors

4. Introduction Inotropes are a class of drugs that change the force of the heart contraction. Vasopressors are drugs with power full and immediate hemodynamic effects that increase the tone of vascular system. The goal of vasopressors is to increase afterload via vasoconstriction and increased arterial pressure. In contrast, inotropes increase cardiac contractility, there by improving stroke volume and cardiac output.

5. Cont,d The most commonly used agents in the ED and ICU are actually inopressors , a combination of both. For discussion purpose inotropes and vasopressors can be categorized in to 3 classes. Inopressors ( norepinephrine, epinephrine and dopamine) Vasopressors(vasopressin and phenylephrine) Inotropes (dobutamine and milrinone)

6. Cont,d Inopressors Have both inotropic and vasopressor effect. Norepinephrine Primarily stimulate alpha-1 and alpha-2 receptors Acting as a balanced venous and arterial vasoconstrictor Has inotropic effect in small amount as beta-1 agonism So, its arterial and venous effect results in increased coronary blood flow ,afterload and preload respectively.

7. Cont,d Norepinephrine is safer than both epinephrine and dopamine -Less arrhythmogenic -Improved CVP, uop , arterial lactate level It is the 1 st –line pressor choice in distributive shock Can be considered 1 st line pressor in cardiogenic shock with profound hypotension

8. Cont,d Epinephrine Stimulates beta-1 and beta-2 receptors More inotropic effect than norepinephrine At higher doses ,it acts primarily as an alpha-1 agonist The 1 st line agent in anaphylactic shock,ACLS 2 nd line after norepinephrine in septic shock Related to tachycardia and lactic acidosis(possibly due to beta agonism)

9. Cont,d Dopamine Natural precursor of norepinephrine and epinephrine Its effect is dose dependent -Low dose-renal vasodilation -Moderate dose-bete-1 agonism predominate -High dose-alpha-1 effect predominate Now only indicated as rescue agent when shock is refractory to other agents

10. Cont,d Dopamine depresses ventilatory response to hypoxemia by upto60% It may also suppress thyrotropin release Have negative effect on cellular function leading to immunosuppression

11. Cont,d Pure inotropes Work primary to increase cardiac output by improving cardiac contractility Can lead to peripheral vasodilation and have a variable effect on BP They may result in hypotension.so prior adequate fluid administration is important Dobutamine and milrinone are known pure inotropes

12. Cont,d Dobutamine A synthetic catecholamine derivative Stimulates beta -1(more) and beta-2 and at high dose it may also stimulate alpha-1 Confers predominantly inotropic effect Due to its vasodilatory effect can improve capillary perfusion independent of changes in BP and cardiac index First line agent in mgt of hypotension associated MI

13. Cont,d Increase myocardial 02 demand and may predispose to dysrhythmia High does(acute) lowers thyroid stimulating hormone with unknown mechanism Used only intravenously

14. Cont,d Milrinone is a phosphodiesterase-3 inhibitor PDE3 Causes cardiac smooth muscle relaxation and peripheral vasoconstriction PDE3 inhibition results in potent inotropy Used in patients with daily beta-blocker use and in patients with long standing heart failure who developed resistance to catecholamines Avoid in renal failure

15. Cont,d Pure vasopressors Phenylephrine Is a pure alpha-1 agonist Primarily affects large arterioles Indicated in neurogenic shock with normal cardiac output Because it causes reflex bradycardia, should only initiated with norepinephrine

16. Cont,d Vasopressin Also known as anti-diuretic hormone Increase risk of digital ischemia more significantly than catecholamines No enough evidence to support to use it through peripheral iv line As 2 nd line agent in refractory septic shock Used in DI and variceal bleeding

17. Cont,d PPV/PEEP as inotropes The effect is significant in patients with lv failure -Decrease work of breathing -Decrease afterload so that increase CO Should be attempted when inotropes are weaned off or at low dose -Extubation is a critical time for a patient in need of inotropes for cardiac dysfunction

18. Cont,d Titration and weaning of inopressors Inotropes and vasoactive medications are targeted towards the pre-decided therapeutic goals. Mean arterial pressure(MAP) is the most commomly used objective measurement resuscitation goal. inopressors dose may be increased to achieve age-appropriate MAP (MAP – CVP = perfusion pressure).

19. Cont,d Clinical conditions in which maintaining a high normal MAP is recommended are as follows: -Increased intracranial pressure -Chronic hypertension -Renal failure -Intra-abdominal hypertension

20. Cont,d Inotropes and vasoactive medications should be gradually weaned off. Most often, vasoconstrictors are weaned off earlier than the inotropes -resolution of vascular dilatation and capillary leak is one of the earliest signs of shock recovery Only one agent should be weaned off at a time If the patient is mechanically ventilated, he/she should be extubated only when the inotropes have been reduced to low dose or completely weaned off.

21. Reference Rogers’ text book of pediatric intensive care,5 th edition Pediatric critical care manual,2018 edition Tintinalli emergency medicine,9 th edition www.emdoc.com Surviving Sepsis Campaign International Guidelines for the Management of Septic Shock and Sepsis-Associated Organ Dysfunction in Children,2020