chad pressors handout
TRANSCRIPT
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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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Hemodynamic Drugs2 of 11
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
Douglas C. Shook, MD
Department of Anesthesiology, Perioperative and Pain Medicine
Brigham and Womens Hospital
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Hemodynamic Drugs3 of 11
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
Douglas C. Shook, MD
Department of Anesthesiology, Perioperative and Pain Medicine
Brigham and Womens Hospital
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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Hemodynamic Drugs4 of 11
Dont treat epinephrine reactions from local anesthesia injection (BP) with -blockers Cardiovascular collapse.
Douglas C. Shook, MD
Department of Anesthesiology, Perioperative and Pain Medicine
Brigham and Womens Hospital
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Hemodynamic Drugs5 of 11
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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Hemodynamic Drugs6 of 11
o PVCs
Douglas C. Shook, MD
Department of Anesthesiology, Perioperative and Pain Medicine
Brigham and Womens Hospital
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Hemodynamic Drugs7 of 11
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)
Douglas C. Shook, MD
Department of Anesthesiology, Perioperative and Pain MedicineBrigham and Womens Hospital
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Hemodynamic Drugs11 of 11
Douglas C. Shook, MD
Department of Anesthesiology, Perioperative and Pain MedicineBrigham and Womens Hospital
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Douglas C. Shook, MD
Department of Anesthesiology, Perioperative and Pain MedicineBrigham and Womens Hospital