Chad Pressors Handout

8/2/2019 Chad Pressors Handout

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Hemodynamic Drugs1 of 11

Inotropes

Douglas C. Shook, MD

Department of Anesthesiology, Perioperative and Pain Medicine

Brigham and Womens Hospital

Action HR Con Preload SVR/PVR BP CO Indications Use

Ephedrine

Indirect NE releaseMild direct , 1, 2

Acts like small doseepi

nephrine

Low SVR (esp if HR low)Low CO (esp if HR low)

Transient cardiac depression

5-10mg IV bolus25-50mg IM

Tachyphylaxis with repeat dosing

Epinephrine

1, 2, 1, 2 agonist

Dose dependent action1-3mcg/min = 3-10mcg/min = and

10+ mcg/min = and

-/ 1-3

-/ 3-10 10-20

-/ 10-20

Cardiac Arrest

AnaphylaxisCardiogenic shockBronchospasm

Reduced COHypotension

4mg/250ccNS = 16mcg/cc

2-10mcg IV bolus (Never more unless extremis)Infusion 2-20mcg/min (Central line)

Arrest: 0.5-1.0mg IV bolusMonitor end-organ perfusion closely

Dopamine

1, 1, 2, D1 agonist

Indirect NE release1-3g/kg/min = D1

3-10 = 1,2>D110+ = 1>, D

-

-/

Var

/-/

Low COLow SVR

Renal Insufficiency?

200-400mg/250cc = 800-1600mcg/ccInfusion 2-20mcg/kg/min (Central line)

Monitor end-organ perfusion(esp>10mcg/kg/min)

DobutamineStrong 1> 2Weak 1 / -

-

(in -blockedpts)

Var

Low CO (esp with SVR)

Right heart failureStress Echocardiography

250mg/250cc = 1,000mcg/cc

Infusion: 2-30mcg/kg/minOften used with other inotropes/vasopressors

Milrinone

InhibitsPhosphodiesterase IIIIncreases cAMP

Doesnt act at receptorsIncreased contractility

Decreased PVR/SVR

-/ / Var

Low CO (esp with SVR)Right heart failure

Pulm HTNSupplement -agonistsReduced proarrhythmic effect

25-75mcg/kg load over 10min (beware BP)Infusion: 0.375-0.75mcg/kg/min

Reduce infusion in renal failure

GlucagonIncreases intracellular

cAMP - -

Hypoglycemia-blocker toxicity

Low CORefractory CHF

Bolus: 1-5mg IV slowlyInfusion: 25-75mcg/min

Rarely used because of multiple side-effects(N/V, tachycardia, hyperglycemia, hypokalemia,anaphylaxis)

Calcium Chloride Free Ca ion -/ - /

HypocalcemiaHyperkalemiaHypotension from

hypocalcemia, CCB, orprotamine

Anesthetic overdoseCounter act hypermagnesemia

10% Calcium Chloride 100mg/cc200-1000mg slow IVP (prefer central line)Causes vein inflammationDont use immediately after reperfusion

Levosimendan

Calcium-sensitizing agent

Binds to troponin CcAMP-independentVascular dilation K-

ATPase channels

-/ Var

Low CO

Right heart failurePulm HTN

Supplement -agonistsReduced proarrhythmic effect

Bolus: 6-24mcg/kg (10-20min)

Infusion: 0.05-0.4mcg/kg/min (up to 24 hrs)Active metabolite with 80hr half-life

Effects last 24-48hrs after infusion stopped


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Vasoconstrictors

Drug Action HR Con Preload SVR/PVR BP CO Indication Use

Phenylephrine 1-agonist

-/

(reflex)

- - -/

Peripheral vasodilationLow SVR

SVT (Reflex vagal stim)TET spell

40mg/250ccNS = 160mcg/cc10mg/250ccNS = 40mcg/cc

40-80mcg IV bolusInfusion on micro gttStart infusion at 10mcg/min

Norepinephrine

1, 2, 1 agonistIntense 1 and 2

constriction throughoutdosing range

Variable -/ (SVR)

Peripheral vascular collapseShock, vasoplegiaSVR

Need SVR with some Con

Phenylephrine isnt working

8mg/250ccNS = 32mcg/cc2-10mcg IV bolus (extremis only)

Infusion 2-20mcg/min (Central line)Monitor end-organ perfusion closely

Vasopressin

Direct vasoconstriction viaV1 receptors

No action on or receptors

- - - / ? Var

Alt to Epi in Cardiac arrest

Secondline agent:Shock, vasoplegia, sepsis,

SVRPulm HTN with SVR?Physiologic dose with Milrinone

To reduce Norepi dose

Infusion: 0.01-0.04U/min (physiologic)Lower incidence of end-organ hypoperfusion

Infusion: 0.04-0.1U/min (Pharm dose)Monitor end-organ perfusion closely

Bolus: 40U IV for VF arrest

Methylene Blue

Complex mechanismInhibits NO/cGMPInhibits NO synthase

Not a first-line agentLimited clinical trials and case

reportsSVR - Septic shock, SIRS

Refractory post-CPB vasoplegiaDec Norepi requirements

Bolus: 1.5-2.0mg/kg over 15-30minInfusion: 0.25-1.0mg/kg/hrMonitor end-organ perfusion

Vasodilators

Nitroglycerin Direct vasodilatorcGMP production

Venous>Arterial

Excellent coronary effects

(reflex)

(reflex)

(High dose)

/ Myocardial ischemiaIncrease coronary perfusionRelieve coronary spasm

HypertensionArterial dilation (high dose)

Pulmonary HTNCHF

40-80mcg IV bolusInfusion 10-200mcg/minAt infusions higher than 200mcg/min switch to

SNP or at another agent.Tolerance if infused for long periods of time.

Nitroprusside Direct vasodilator

cGMP productionArterial=Venous

(reflex)

(reflex)

/ HTN, SVR

Controlled hypotensionSVR>Preload at lower doses

Infusion 0.1-2.0mcg/kg/min

Avoid doses greater than 2.0 (toxicity)Protect from lightContinuous BP monitoring (A-line)

Taper infusion graduallyUse with caution in liver/kidney dysfunction





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Beta-Blockers

Action

o HR decreased

o Contractility decreased

o SVR unchanged or increased

o AV conduction decreased

o

Atrial refractory period increasedo Automaticity decreased

Indications

o Rx hypertension

o Arrhythmias

o Myocardial ischemia and infarction

o Reduce dynamic ventricular outflow obstruction

o Synergism with nitroglycerin for treating MI

o Reduce perioperative myocardial morbidity and mortality

Monitor for

o Severe bradyarrhythmias

o Heart block

o Bronchospasm

o CHF with low EF

o Withdrawal syndrome with abrupt discontinuation (Hypertension and Tachycardia)

Treatment of toxicity

o -agonists (possible large doses)

o Pacing

o Calcium, milrinone, glucagon, thyroid hormone

Assessment of -blockade

o Minimal or no increase HR with exercise




Drug Action Half-life (Hrs) Elimination IV DosePropranolol 1, 2 antagonist 3.5-6.0 Hepatic 0.5-1.0mg IV prn

Labetolol 1, 2, 1 antagonist

Ratio of : = 1:7

3-8 Hepatic 5-10mg IV prn

Metoprolol 1 antagonist 3-4 Hepatic 1-5mg IV prn

Esmolol

Excellent during

intubation/extubation

1 antagonist 9 min RBC esterase 0.25-0.5mg/kg IV prn

Infusion

50-200mcg/kg/min


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Dont treat epinephrine reactions from local anesthesia injection (BP) with -blockers Cardiovascular collapse.





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Calcium Channel Blockers

Drug Action Half-life Elimination IV Dose Info

Verapamil Calcium Channel

Blocker

3-10 hrs Hepatic Vial 5mg/2cc

0.625-1.25mg IV prn

(Low dose)

Myocardial depression>Peripheral arterial vasodilation

Use low doses with GA or unstable patients

Rx: SVT, HTN, vasospasm, ischemia, LV outflow obstruction, Effects

o Peripheral arterial vasodilation

o Venodilation is minimal

o Coronary dilation

o Depression of myocardial contractility (Verapamil>Diltiazem>Nicardipine)

o Improving myocardial ischemia

o Prolonging AV refractory period (Verapamil, Diltiazem)

o Decreased sinus rate (Verapamil, Diltiazem)

Indications

o MI

o

HTNo LV outflow obstruction

o Vasospasm

o Migraine prophylaxis

o Arrhythmias (Verapamil, Diltiazem)

Toxicity

o Give Calcium Chloride, -agonists, milrinone, pacing

Muscarinic Antagonist

Drug Action Half-life Elimination IV Dose Info

Atropine Blockade of Ach atmuscarinic receptors

Variable Renal>Hepatic 0.4-1.0mg IV Dosing for bradycardiaMay exacerbate bradycardia with dose


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o PVCs





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Important Tips

Drug Dosage Calculations and Infusions Drug errors one of the most common causes of accidental injury to patients.

Always ask for help if you have not used a drug before.

Drugs are given in mg, mcg, and units.

Not all drugs are labeled in a uniform manner.

o Example epinephrine in the standard drug kit.

Epi Vial = 1:1000 = 1mg/cc

Epi box = 1:10,000 = 100mcg/cc Both are very high concentrations

Concentrations as ratios

o 1:1000 = 1gm/1000mL = 1mg/mL

o 1:10,000 = 0.1mg/mL = 100mcg/mL

o 1:100,000 = 0.01mg/mL = 10mcg/mL

o 1:200,000 = 0.005mg/mL = 5mcg/mL

o

1:1,000,000 = 1g/million mL = 1mcg/ml Concentrations as percents

o x% = Xg/dL = Xg/100mL = 10xXmg/mL

o 2% Lidocaine = 20mg/mL

Look at the label before mixing

o Example epinephrine vs ephedrine

o Dilution in 10cc yields very different effects for the patient.

Standard concentrations used at BWH.

o Phenylephrine 40mg/250cc (160mcg/cc)

o Epinephrine 4mg/250cc (16mcg/cc)

o Norepinephrine 8mg/250cc (32mcg/cc)


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Patients on Reserpine, Tricyclic Antidepressants, and MAO inhibitors

Reserpineo Depletes intraneuronal NE leading to denervation hypersensitivity

o Indirect acting agents (ephedrine) show diminished effect.

o Direct acting agents may produce exaggerated effects.

TCAs and MAO inhibitors

o These drugs increase the availability of NE at receptors.

o Indirect acting agents show an exaggerated response (life threatening hypertension)

o

Use direct acting agents in these patients. Start with small doses.o The response is greatest in the first 14-21 days of treatment.

o If a reaction does occur use a vasodilator.


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Appendix A

Classification of Receptors with Organ and ResponseReceptor Organ ResponseBeta-1 Heart

Adipose tissue

Renal

Increased HR

Increased contractility

Increased conduction velocityAutomaticity

Risk of arrhythmias

Lipolysis

Renin releaseBeta-2 Heart (less potent)

Vascular (Muscle)

Bronchial

UterusRenal

Liver

Pancreas

Increased HR

Increased ContractilityDilation

Dilation

RelaxationRenin release

Gluconeogensis

Insulin releaseAlpha-1 Vascular (less brain/heart)

Heart (less potent)

Pancreas

Intestine/Bladder

Constriction (arterial and venous)

Increase contractility

Decrease HRInhibit insulin secretion

Relaxation

Constriction of sphincters

Alpha-2Presynaptic CNS Inhibits NE, Ach, serotonin, dopamine, and

substance P release (sedation, Dec BP, etc)


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Appendix B (Important Slides From Talk)


Department of Anesthesiology, Perioperative and Pain MedicineBrigham and Womens Hospital


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