Treating Hemodynamic Disturbances and Threats to Tissue Oxygenation: A Review of Commonly Used PIC/NIC Medications Julie Warren RN, MSN, CCRN Pediatric CNS 4/2013-Current

Intravenous Infusion Guidelines Most hemodynamic drugs have a rapid onset and are almost all given intravenously Understand how long it will take for new dose to clear IV tubing containing an old dose: Don’t “treat” the line, treat the patient!

Alteration in the Autonomic Nervous System Responses Contractile state = inotropy Heart rate = chronotropy Speed of conduction = dromotropy

Inotropes An increased intracellular calcium concentration is the central cellular event that enhances contractility of the myocardium Inotropes work in one of two ways: Stimulate receptors to increase cAMP (cyclic adenosine monophosphate) which ultimately increases intracellular calcium Inhibit phosphodiesterase (PDE) which then increases cAMP Digitalis glycosides also enhance contractility but don’t use the cAMP “route”

Increasing Cardiac Strength Use of inotropes and preload reducers

Dopamine: Dose varies based on intent: Primary side effects: 0.5-2 mcg/kg/min: renal perfusion/diuresis 2-5 mcg/kg/min: increased contractility and C.O. (little HR inc) 5-6 mcg/kg/min: HR and BP increase plus increased C.O. 10-20 mcg/kg/min: increased SVR/BP and HR Primary side effects: tachycardia increased myocardial oxygen consumption (MVO2)

Dobutamine Improves contractility followed by  CVP,  SVR,  PVR Dose: 2-5 mcg/kg/min to start Maximum effects at 10-15 mcg/kg/min Max dose not known Primary side effects: tachycardia increased myocardial oxygen consumption (MVO2) potential hypotension arrhythmias

Epinephrine: Dose varies based on intent: Primary side effects: 0.05-0.3 mcg/kg/min: Improves contractility and C.O. through peripheral vasodilation, HR, SVR,  PVR 0.01-1mcg/kg/min: for asystole or pulseless arrest > 0.3 mcg/kg/min: SVR and  BP; but vasoconstricts renal arteries Primary side effects: tachycardia increased myocardial oxygen consumption (MVO2) arrhythmias hypertension CNS excitation: restlessness/dread/fear

Norepinephrine Its hemodynamic effects limit its use in pediatrics almost exclusively to treatment of septic shock; used to improve vascular tone after numerous boluses and other inotropes fail Dose varies based on intent: 0.05-0.1 mcg/kg/min: Sharp  in SVR; improves contractility and C.O.if the increase in afterload can be tolerated 1-2 mcg/kg/min maximum Primary side effects: profound hypertension ischemic injury of the extremities CNS excitation: restlessness/dread/fear

Milrinone (Primacor) CO, SV,  SVR,  PVR,  CVP A Bipyridine that works as a Phosphodiasterase (PDE) inhibitor/ “Inodilator” Increases cAMP content for an inotropic effect with reduced O2 demand CO, SV,  SVR,  PVR,  CVP Mix in NS or 5% Dextrose Dose: Loading dose of 50 mcg/kg over 10 minutes 0.275-0.75 mcg/kg/min infusion Side Effects: hypotension and arrhythmias

Review of Receptor Sites Increases contractility; LOCATIONS PRIMARY ACTION ALPHA-ADRENERGIC Alpha 1 Vascular smooth muscle Arterioles and venules Increases intracellular CA++; Muscle contraction; Constriction; Inhibits insulin secretion Alpha 2 Presynaptic nerve terminals Decreases cAMP; Inhibits norepi release; vasodilation; Negative chronotropy (HR) BETA ADRENERGIC Beta 1 Heart innervation: SA node AV node Increases contractility; Increases heart rate; Increases automaticity; Increases cAMP; Enhances renin secretion Beta 2 Pulmonary smooth muscle Dilation; Relaxation Increases cAMP; Bronchodilation; Enhanced glucagon secretion DOPAMINERGIC Vascular smooth muscle: renal, coronary, mesenteric Dilation

Effects of Commonly Used Inotropes Agent Dose (mcg/kg/min) Peripheral Vascular Effects Alpha(+) = Constricting Beta 2 (-) = Dilating Cardiac Effects Beta 1 (+) = ↑contractility Beta 2 (+) = ↑contractility Alpha (+) Beta 2 (-) DA Beta 1 Beta 2 Dopamine 2-5 2+ 5-10 1-2+ > 10 2-3+ Dobutamine 2-10 1+ 3+ Epinephrine 0.05-0.1 Norepinephrine 0.05-0.5

Diuretics Furosemide Side Effects: Dose 1-2 mg/kg q 6-12 hrs, given at max rate of 0.5 mg/kg/min; If larger doses required (>120 mg), the infusion rate should not exceed 4 mg/min Can dilute to 1-2 mg/ml and give over 10-15 mins Continuous IV infusion: 0.05 mg/kg/hr titrated for clinical effectiveness Side Effects: Hypovolemia/hypotension Hypokalemia/hyponatremia/hypochloremia Ototoxicity Metabolic alkalosis

Other Diuretics

Cautions with Diuretics Used cautiously in patients who are hypotensive due to potential to further reduce BP Can cause fluid and electrolyte abnormalities altered potassium and magnesium dehydration/hypovolemia Urine output is not always a reliable method of estimating preload reduction

Afterload Reducers

Nitroprusside (Nipride) Balanced vasodilator: equal effects on venous and arterial circulation If SVR is not elevated, SV and CO/CI decline and BP is reduced; HR increases as result When SVR is high and contractility is depressed, the reduction in preload and afterload result in increased SV and CO/CI; the increase in SV is proportional to the decrease in SVR; HR declines and BP is unchanged Dose: Given in 5% Dextrose- bag and tubing must be opaque or covered 0.5 mcg/kg/min starting dose 1.5-2 mcg/kg/min usually reduce SVR; highest dose is 10 mcg/kg/min very rapid onset of action; effects stop 3 mins after infusion d/c’d Side Effects: byproduct of breakdown is NO and cyanide (toxic) use only for short periods (< 72 hrs) measure cyanide levels by measuring lactate levels hypotension

Afterload Reducers The other key afterload reducer is Milrinone Nitroglycerine is rarely used in children Calcium channel blockers rarely used: Nifedipine has been tried in hypertensive emergencies and to treat patients with hypertrophic cardiomyopathy (BP lowering effect in kids is not predictable however) Diltiazem-has emerged as an effective agent for SVT and atrial fib/flutter ACE inhibitors: Captopril/Enalopril Also reduce preload

Other Key Drugs Digoxin (increases contractility and has antiarrhythmic properties) Antiarryhthmics Adenosine (SVT) Procainamide (SVT/JET/atrial ectopic tachycardia) Lidocaine (Vtach/Vfib) Amiodorone (Vtach/Vfib) Esmolol (tachyarrhythmias) Sotalol (refractory SVT/VT) Triiodothyronine (T3) -increases CO/decreases SVR Ca++ (increases contractility) Nesiritide /Natrecor (diuretic/natriuretic/vasodilator)

Other Key Drugs Pulmonary Bed Vasodilators: Oxygen Prostaglandins (also dilates PDA) iNO Prostacyclins: Epoprostenol (Flolan) Endothelin Receptor Antagonists: Bosentan (Tracleer) Phosphodiesterase Inhibitors: Sildenafil (Viagra) - oral Pulmonary Bed Vasoconstrictors: Nitrogen CO2

Miscellaneous Drugs Insulin Infusions for DKA: Refer to DKA Protocol Heparin infusions: Refer to Heparin Protocol (pilot) Propofol/Diprivan: Short term use only!!!!

Nursing Responsibilities in Checking Drips At the start of each shift, you must check each pump for the correct infusion rate and medication - calculate the rate, don’t trust the pump! For each new medication infusion order or rate change, you must manually calculate the drip rate and have it independently double-checked by a second nurse

Let’s Shift Gears: Drip Calculations

Calculating Drips Two methods can be used: Use / memorize formulas and plug in your numbers Use conversion ratios: extremely useful if you forget formulas! Plus, there isn’t a formula for everything we calculate

Calculating Drips Try to remember that there is more than one step. With either method, start with what you know You will need to know the patient’s weight in kilograms (# lbs divided by 2.2) You will need the # milligrams of medication in the solution You will need the amount of solution in milliliters (ml’s) You will need to know the infusion rate ordered (mcg/kg/min)

Calculation: Example #1 Epi drip is ordered at .05 mcg/kg/min Pt weighs 4.1 kg Your epi syringe comes labeled .064 mg/ml How fast do you run the pump (ml/hr)?

Calculation: Example #1 Use/ memorize the formula: cc/hr = (mcg/kg/min) x (60 mins) x (wt in kg) syringe/drip concentration in mcg Fill in the “knowns” and do the math: cc/hr = (.05) x (60) x (4.1) = 12.3 = .19 cc/hr 64 64

Calculation: Example #2 Dopamine drip ordered at 5 mcg/kg/min Pt weighs 11 kg Your dopamine syringe comes labeled 80 mg/ 50ml How fast do you run the pump (ml/hr)?

Calculation: Example #2A Use/memorize the formula: cc/hr = (mcg/kg/min) x (60 mins) x (wt in kg) syringe/drip concentration in mcg Fill in the “knowns” and do the math: cc/hr= (5) x (60) x (11) = 3300 = 2.1 cc/hr 1600 1600

Calculation: Example #2B Use the formula but place the syringe med concentration in the denominator; if it’s already in mcg you are all set; if it’s in mg, do the math and then move the decimals after you get your answer cc/hr = (mcg/kg/min) x (60 mins) x (wt in kg) _________________________________________________________________________________________________________________________ syringe/drip concentration in mg

Calculation: Example #2B The easiest way?? Med concentration: 80 mg/50 mls= 1.6 mg/ml cc/hr= (5) x (60) x (11) = 3300 = 2062 ______________________________________________________________ _____________ 1.6 1.6 Now move the decimal because the denominator was in mg not mcg Answer: 2.062 or 2.1 cc/hr

What if you know the infusion rate but don’t know the mcg/kg/min? This calculation is used when you need to work the other way: you’ve been titrating or weaning your drip (turning the rate up/down) or a patient comes to you from the O.R. or from outside transport Use the following formula and plug in pump rate, pt wt, and drip concentration: mcg/kg/min= (rate) x (*drip concentration) (pt wt) x (60) * in mcg/ml

Using Conversion Ratios When All Else Fails Set up equivalent formulas from what you know such as: 1 lb = 2.2 kg 1 mg = 1000 mcg 1 hour= 60 mins Set up your equation so that numerators cancel out with denominators and what you want to find out is set up correctly (cc/hr not hr/cc).

A Conversion Ratio Example 1 gorp = 2.2 burps 1 dweeb = 1000 mini dweebs 1 jerp = 60 flibs 10 burps = 1000 mini dweebs 6 dweebs= 5 flibs How many jerps would you have if you had 20 gorps?

Start with what you have and what you want Have 20 gorps       ? Jerps Set up your conversion ratios so that units cancel out correctly:

Let’s Try An Easy One Ativan ordered to be given: 1.25 mg It comes as 2 mg /ml Another nurse has drawn up 0.75 ml and asks you to check his/her math Did he/she draw up the correct amount?

Using Conversion Ratios

Let’s try using Conversion Ratios with our Epi example from earlier Epi drip ordered at .05 mcg/kg/min Pt weighs 4.1 kg Epi syringe comes labeled .064 mg/ml How fast should you set you pump?

Start with what you have and what you want

Let’s try Milrinone Ordered dose is .5 mcg/kg/min Pharmacy sends you 50 cc of Milrinone in a 60 cc syringe labeled 20 mg/100 ml Your patient weighs 14 kg What rate do you set your pump???

Using Conversion Ratios

Let’s see if our Milrinone rate is correct using the “formula” cc/hr = (mcg/kg/min) x (60 mins) x (wt in kg) *syringe/drip concentration in mcg Convert the syringe/drip concentration to mcg/ml: * 20 mg/100 ml = .2 mg/ml= 200 mcg/ml Fill in the “knowns” and do the math: cc/hr= (.5) x (60) x (14) = 420 = 2.1 cc/hr 200 200

Your patient is receiving Fentanyl at 1.3 ml/hr Now You Try!! Your patient is receiving Fentanyl at 1.3 ml/hr The syringe is mixed 500 mcg in 50 cc How many mcg/hr is your patient receiving? 1.3 X 500 = 13 mcg/hr 1.3 ml/ 1hr X 500 mcg/50 ml = 13 mcg/hr

Another One! You’ve just come on duty to find your patient is on a dobutamine drip at 10cc/hr. You want to check the dose/rate against the original order. Your pt weighs 20 kg The dobutamine syringe reads “50 mg in 50 cc D5W” How many mcg/kg/min is the dobutamine currently infusing at? 10cc/1 hr X 50 mg/50cc X 1000 mcg/1 mg x 1 hr/60 min X 1/20 kg= 10,000/1200 = 8.3 mcg/kg/min

Propofol Ordered mcg/kg/min as an infusion Ordered mg/kg as incremental doses

Precedex (mcg/kg/hr) Use the following formula: cc/hr = (dose ordered in mcg/kg/hr) x (wt in kg) syringe/drip concentration: mcg/ml

Precedex Dose ordered: 0.2mcg/kg/hr Pt weight: 12 kg Syringe concentration is: 4 mcg/ml How fast would you run the pump? If you needed to titrate the drip- What would the rate be for 0.3mcg/kg/hr? 0.4mcg/kg/hr? 0.2 x 12 divided by 4 is 0.6 cc/hr…………………… 0.2mcg/kg/hr=0.6 cc/hr …………………………………………………………………0.3 mcg/kg/hr=0.9 cc/hr …………………………………………………………………0.4 mcg/kg/hr= 1.2 cc/hr

Almost Done!! A new “experimental drug” has just been approved for use on your patient following approval by the IRB Drug “x” is mixed as 20 units in a 50 cc syringe You are to infuse this new drug at a rate of 3 units/kg/hr Your pt weighs 5 kg How fast do you set your pump??? 3 units/1kg-hr x 5kg/1 x 50cc/20units= 3x5x50/20= 750/20= 37.5 cc/hr……..have pharmacy remix more concentrated

Last One!!!!!! You’ve just received an order to begin dopamine at 10 mcg/kg/min Your pt weighs 22 lbs Pharmacy sends you a syringe labeled “40 mg in 50cc” What rate do you set your pump at??? First: 22lbs=10 kg 10mcg/kg-min x 1mg/1000mcg x 50cc/40 mg x 60/1 hr x 10kg/1= 7.5cc/hr Or to use the formula, you need to convert 40mg in 50 cc to ??? mg in 1000 cc: 40 is to 50 as x is to 1000= 40000/50= 800