Drips

DRIPDRIPTRICKSTRICKS

Medication Calculations• In Critical Care, often medications are

ordered as IV continuous drips• These medications are potent and requires

constant monitoring to assess for desired effect and potential side effects

Medications may be ordered in:

• “mg/hr”: Lasix and Aminophylline • “units/hr”: Heparin and Insulin • “mcg/min”: Nitroglycerin • “mcg/kg/min”: Dopamine and Dobutamine• “mg/min”: Lidocaine

Units of Measure• 1000 μg = 1

mg • 1000 mg = 1g • 1000 g = 1 kg

• 1 kg = 2.205 lbs.

• 1000 mL = 1 L • 1 mL = 1 cc = 1

cm3To convert from one multiple to the other, move

the decimal point 3 places in the direction indicated

kg 3g 3 mg 3 μg

Drip Formulasmg/ml mg of medicine

mL of solution

mg/hr mg of medicinemL of solution

x infusion rate (ml/hr)

mg/min mg of medicinemL of solution

x infusion rate ÷ 60 (ml/hr)

mg/kg/min

mg of medicinemL of solution

x infusion rate ÷ 60 ÷ pt.’s weight in kg (ml/hr)

Drip Formulasμg/ml mg of medicine x

1000mL of solution

μg/hr mg of medicine x 1000

mL of solution

x infusion rate (ml/hr)

μg/min mg of medicine x 1000

mL of solution

x infusion rate ÷ 60 (ml/hr)

μg/kg/min

mg of medicine x 1000

mL of solution

x infusion rate ÷ 60 ÷ pt.’s weight in kg (ml/hr)

Drip Formulas

Rate in gtts/min

volume to be given

hrs to be given

x # of gtts/ml of IV set ÷ 60

Rate in mL/hr

μg/kg/min to be given x 60 x pt.’s weight in kgdrip concentration in μg/mL

Rate in mL/hr

mg/kg/min to be given x 60 x pt.’s weight in kgdrip concentration in mg/mL

Calculating Drops Per Minutegtts/min = volume to be infused X gtts/mL of administration set

total time in minutes

Infuse 500 cc of PNSS over 3 hours. Using a 15 gtts/mL administration set what drip rate would you use?

gtts/min = 500 mL X 15 gtts/mL = 41.66 gtts/min

180 minutes

Calculating Solution Concentration

mg in solution divided by mL in solution

To prepare your lidocaine infusion you have mixed 2 grams of lidocaine into 500 mL of D5W. How much lidocaine is in 1 mL of this solution?

2000 mg = 4 mg/mL500 mL

Calculating Solution Concentration

To prepare your dopamine infusion you have mixed 800 mg of dopamine into 500 mL of D5W. How much dopamine is in 1 mL of this solution?

800 mg = 1.6 mg *1.6 mg X 1000 = 1600 μg/mL500 mL

Calculating mg/min OR Calculating μg/min

gtts/min = volume on hand X drip factor X desired dose

dosage on hand

Administer 2 mg per minute of lidocaine to a patient. To prepare the infusion you mix 2 grams of lidocaine in an IV bag containing 500 mL of D5W. You will use a microdrop administration set (60 gtts/mL). Calculate the infusion rate.

gtts/min = 500 mL X 60 gtts/mL X 2 mg = 30 gtts/min2000 mg

Calculating μg/kg/mingtts/min = desired dose X weight (kg) X drip factor

solution concentration

Administer 5 mcg/kg/min of dopamine to a patient weighing 85 kg. To prepare the infusion you mix 800 mg of dopamine in 500 mL of D5W (1600 mcg/mL). You will use a mIcrodrop administration set (60 gtts/mL). Calculate the infusion rate.

gtts/min = 5 mcg X 85 kg X 60 gtts/mL = 15.94 gtts/min1600 μg

Calculating μg/kg/minUsing the same information from the above patient calculate the same infusion using a macrodrop administration set (15 gtts/mL).

gtts/min = 5 mcg X 85 kg X 15 gtts/mL = 3.98 gtts/min1600 μg

Drip Trick #1: C Factor x pump rate = μg/kg/min

• There’s standard drip mixture hanging, and you’re having to titrate often. To simplify the calculation of μg/kg/min each time you change the infusion rate, calculate a constant (C factor or Magic Number)

• Each time you change the infusion rate, multiple the new rate by the C factor to determine the μg/kg/min you are now givingC = mg of med X 1000 ÷ 60 ÷ pt’s

wgt in kg mL of solution

Drip Trick #1: C Factor x pump rate = μg/kg/min

• you have Dopamine 800mg mixed in 500mL and your patient weighs 70kg.

C = 800 X 1000 ÷ 60 ÷ 70 500C = 0.38

C Factor x Pump Rate = μg/kg/min 0.38 x 10 mL/hr = 3.8 μg/kg/min 0.38 x 15 mL/hr = 5.7 μg/kg/min 0.38 x 25 mL/hr = 9.5 μg/kg/min 0.38 x 40 mL/hr = 15.2 μg/kg/min

Drip Trick #2: pump rate = μg/kg/min

• If you mix the drip according to the patient’s weight, the infusion rate dialed into the pump (the mL/hr) will equal the dose in μg/kg/min

the mg of med = 60 x pt wt in kg x mL of solution you want to mix in

you need 1000


For a patient weighing 70kg, you want to know how many mg of Dopamine to mix in 500mL of solution, so that the mL/hr infusion rate equals the μg/kg/min

mg of Dopamine = 60 x 70kg x 500mL = 2100mg 1000So if you mix: 2100 mg of Dopamine in 500mL

An infusion rate of 5mL/hr delivers 5 μg/kg/min 10mL/hr delivers 10 μg/kg/min

20mL/hr delivers 20 μg/kg/min 30mL/hr delivers 30 μg/kg/min


If you want a more dilute mixture, cut the mg in half (2100mg/2 = 1050)

So that when you mix: 1050 mg of Dopamine in 500mL

An infusion rate of 5mL/hr delivers 2.5 μg/kg/min 10mL/hr delivers 5 μg/kg/min

20mL/hr delivers 10 μg/kg/min

30mL/hr delivers 15 μg/kg/min

Common Drips

Aminophylline• Bronchodilator, bronchial smooth muscle

relaxant, for treatment of acute asthma or bronchospasm associated with chronic bronchitis or emphysema

• AE: Irritability, restlessness, tremor, insomnia, headache, dizziness, drug-related seizures, tachycardia, palpitations, extrasystoles, hypotension, nausea, vomiting, anorexia, abdominal pain, diarrhea, tachypnea, respiratory arrest

Aminophylline• Prep: 25mg/mL in 10mL vial• IVP: 5mg/kg loading dose slowly over 30

minutes (no faster than 20mg/min)• Drip: 500mg/500mL D5W/NS• Concentration 1mg/mL• Dose: 0.5 – 1.5 mg/kg/hr

Amiodarone• Anthiarrhythmic with effects on Na, K and

Ca channels, as well a Beta blocking properties

• AE: Hypotension in 16% of patients (related to rate of indusion); Bradycardia occurs in 5%; New onset Vtach/Vfib or Torsades De Pointes, pulmonary infiltrates

Amiodarone• Prep: 50mg/mL in 3mL amp• IVP: 150mg in 100mL D5W over 10 mins• Drip: 900mg/500mL (D5W-Glass)\• Concentration: 1.8mg/ml

* stable in plastic up to 2 hours, stable in glass up to 24 hours

• Dose: 1mg/min X 6 hours to give 360, then 0.5mg/min X 18 hours to give 540mg

• If breakthrough Vtach occurs: 150mg in 100D5W bolus then increase drip rate

Diltiazem• Ca channel blocker with potent negative

chronotropic and mild negative inotropic effects; for acute Afib and Aflutter

• AE: Hypotension, flushing, 2nd or 3rd degree AV Block, bradycardia, asystole, Vtach, Vfib, LV failure, dyspnea, peripheral edema, chest pain, Nausea, vomiting, dry mouth, constipation, injection site reaction

Diltiazem• Prep: 5mg/ml in 25 & 50 mL vials• IVP: 0.25 mg/kg (about 20mg) over 2 mins;

if inadequate response, wait 15 mins, then 0.35mg/kg

• Drip: 125mg/25mL Diltiazem + 100ml D5W/NS

• Concentration: 1mg/mL• Dose: 5-15mg/hr Titrate to HR• Do not give >15mg/hr or for >24 hours

Dobutamine• Synthetic sympathomimetic catecholamine

with inotropic, chronotropic & vasodilator effects. For heart failure, especially with ↑ SVR & ↑ PVR, and for RV infarction.

• AE: Dose related tachycardia can Myocardial ischemia. PVC’s, & ↑ infarct size. ↑ vent. Response to A fib, Headache, nausea, tremor, ↑ BP (may be precipitous), ↓ K, HA, dyspnea, palpitations, nausea.

Dobutamine• Prep: 250mg in 20mL vial.• IVP: N A• Drip: 500mg/500mL D5W, NS, D5NS, RL• Conc: 1000 µg/mL

• Or: 1000mg/500mL D5W, NS, D5NS, RL• Conc: 2000 µg/mL

• OK if solution is pink, avoid alkaline solutions

• Dose: 2-10 µg/kg/min (up to 40 µg/kg/min)

• May need to ↑ dose for pt on β-blockers

Dopamine• Cathecolamine precursor of epinephrine &

norepinephrine with inotropic, chronotropic and vasoactive effects.

• For bradycardia that is refractory to atropine

• For heart failure, hypotension unresponsive to fluids, septic and anaphylactic shock. No longer recommended for oliguric renal failure

• AE: At low dose may decrease BP, at high dose increase HR & SVR, tachycardia, increase MVO2, PVC’s, myocardial ischemia, atrial and ventricular arrhythmias, renal ischemia at high dose

Dopamine• Prep: 40mg/mL in 5mL; 80mg/mL in 5mL• IVP: NA• Drip: 800mg/500mL (D5/D5NS/NS/RL)• Conc: 1600µg/mL• Dosing: • 1-3 µg/kg/min: increase renal perfusion• 3-10 µg/kg/min: increase contractility• >10 µg/kg/min: vasoconstriction• >20 µg/kg/min like Levophed

Epinephrine• Natural & potent cathecolamine with

both alpha and beta adrenergic agonist effects; increases BP, HR, SVR, cerebral and coronary blood flow, myocardial O2 demand, contractility, automaticity;

• For PEA, asystole, bradycardia, VTach, Vfib unresponsive to defibrillation; anaphylaxis

• AE: hypertension, headache, tremors, myocardial ischemia, increase MVO2, tachycardia, ectopy, Vfib, renal ischemia, CVA

Epinephrine• Prep: 1mg/mL in 1mL amp• IVP: for cardiac arrest 1mg q3-5 mins• Drip: 2mg/250mL (D5/NS)• Conc: 8 µg/mL• Dose: start at 1 µg/min then 2.0-10 µg/min• ET: 2-2.5 times the IV dose

Furosemide• Potent, rapid acting diuretic (inhibits the

reabsorption of Na, K H2O) & venodilator for pulmonary edema associated with LV failure, also for nephrotic syndrome, ascites and hypertension

• AE: dehydration, hypotension, hyponatremia, hypokalemia, hypocalcemia, hypomagnesemia, hyperosmolality, metabolic alkalosis, ototoxicity at high doses

Furosemide• Prep: 10mg/mL in 2, 4, 10 mL amps & vials• IVP: 0.5-1.0 mg/kg over 1-2 mins repeat to

total of 2mg/kg• Drip: 250mg/250mL (D5W, NS, RL)• Conc: 1mg/mL• Dose: 2-20mg/hr (do not exceed 1g/day

total)

Lidocaine• An antidysryhtmic, may be used to supress

ventricular ectopy and treat Vfib/Vtach that persists after defibrilation, epinephrine, and Amiodarone.

• Second choice behind Amiodarone and Procainamide for hemodynamically stable V Tach

• Ineffective against atrial arrhythmias• AE: Myocardial depression, ↓ BP. Aggravation

of arrhythmia, respiratory depression / arrest. Bradycardia.

• Toxicity: drowsy, disoriented, paresthesias, muscle twitching, grand mal seizure.

Lidocaine• Prep: For IVP: 100 mg/ 5 mL in syringe• For drip: 1 gram in 50 mL• IVP: 1.0-1.5 mg/kg; if no response, repeat

q 5-10 mins to total 3 mg/kg (1/2 these dosages if pt has ↓ hepatic blood flow or is over 70 y/o)

• Drip: 2 gm/500 mL D5W• Conc: 4mg/mL• Dose: 1-4 mg/min, titrate in increments of

1 mg/min, repeat bolus with each ↑

Magnesium Sulfate• Replacement therapy for Mg deficiency. • Hypomagnesemia can precipitate refractory

Vtach, Vfib, pump inefficiency, sudden cardiac death

• May benefit polymorphic VTach (Torsades de Pointes)

• AE: hypermagnesemia, expecially in pts with renbal insufficiency, flushing, sweating, sensation of heat, hypotension (keep patient supine), paralysis, respiratory paralysis, circulatory collapse, cardiac arrest, CNS depression (have Ca on hand)

Magnesium Sulfate• Prep: • 10% = 0.10 g/mL = 0.8 mEq/mL• 20% = 0.20 g/mL = 1.6 mEq/mL• 50% = 0.50 g/mL = 4.0 mEq/mL

• IVP: 1-2 g in 50 -100 mL D5W over 5-60 mins

• Drip: 1-2g/100mL D5W/NS• Conc: 0.01-0.20 g/mL or 0.08-0.16 mEq/mL• Dose: 1-2 g/hr (or 8-16 mEq/hr)

Nicardipine• A calcium channel blocker with potent

vasodilatory effect on systemic, coronary, cerebral and renal vasculature

• Used to treat hypertension and angina• During PTCA, pretreatment with

intracoronary Nicardipene protects against ischemia

• AE: irritation at infusion site (rotate site q12 hrs), hypotension, flushing, dizziness, tachycardia, PVC’s, palpitations,

Nicardipine• Prep: 25mg/mL in 10mL amp (2.5mg/ml)• IVP: NA• Drip: 25mg/250mL D5W/NS • Conc: 0.1mg/mL• Dose: 5mg/hr (50mL/hr), increase

increments of 2.5mg/hr (25ml/hr) q14 mins to max of 15mg/hr

• Reduce dose in pts with hepatic disease

Nitroglycerin• Dilates peripheral/coronary vasculature by

relaxing vascular smooth muscle. • For treatment of myocardial ischemia and

infarction and to ↑ coronary blood flow in CHF.

• Also to ↓ preload and ↓ afterload in left ventricular failure. Preferred over Nipride in pts with CAD.

• To treat hypertension after cardiac surgery.

Nitroglycerin• AE: Hypovolemia, hypotension, (put head

down, feet up).• Fainting if pt sits up, Reflex tachycardia,

Headache, flushing, 15% are resistant to its antihypertensive effects, Develop tolerance over 1-2 d.

Nitroglycerin• Prep: 5 mg/mL in 1, 5, & 10 mL vials.• IVP: May give 12.5-25 µg bolus• Drip: 50 mg/ 250 mL D5W in glass, with

nonabsorbing tubing• Conc: 200 µg/mL • Dose: 5-20 µg/min, ↑ in increments of 5

µg/min q 5-10 mins (max dose is 200 µg/min). If topical or po doses started, ↓ drip to < 20 µg/min.

Norepinephrine (Levophed)

• Naturally ocurring catecholamine with potent α1, α2, β1, β2 agonist activity. Vasoconstrictive effects used for the treatment of hypotension due to low SVR (septic shock).

• Increases contractility and MVO2.• β1 effects are similar to the Epi, has

minimal β2 effect.


• AE: Hypertension, Myocardial ischemia, Arrhythmias, bradycardia, ↓ Renal/mesenteric blood flow, Tissue slough if it infiltrates.


• Prep: 1 mg/mL in 4 mL amp.• IVP: NA• Drip: 8 mg/500 mL D5W, D5NS, not NS• Conc: 16 µg/mL• Dose: 2-12 µg/min (up to 30 µg/min) • Start at 0.5 µg/min• Expect great individual differences in dose

required.

Potassium Chloride• To prevent or treat potassium deficiency.• ↓ K is most often due to:• Corticosteroids• Diuretics• NG suction, vomiting, diarrhea,

Metabolic acidosis

Potassium Chloride• AE: If given peripherally, pain / irritation of

IV site and peripheral vein.• Toxicity (K > 5.5): confusion, irritability,

flaccid paralysis, respiratory distress, ↓ BP arrhythmias, widened QRS, prolonged PR and QT -> V fib.

Potassium Chloride• Prep: 2 mEq/mL in 10 & 20 mL vials• IVP: Never• Drip: • Rapid replacement: 10-40 mEq/100 mL

D5W (use central line)• Slow replacement: 20-40 mEq/1000mL

(peripheral line)• Dose: 5-40 mEq/hr (Never > 40 mEq/hr)

Sodium Bicarbonate• The most widely used buffering agent, but

no longer routinely used in cardiac arrest unless pt has:• Preexisting metabolic acidosis• Hyperkalemia• Tricyclic or phenobarb overdose• Prolonged CPR

Sodium Bicarbonate• AE: Iatrogenically induced alkalosis,

Hypernatremia, Hyperosmolality, Left shift of O2 / Hgb curve can compromise release of O2 to tissues.

Sodium Bicarbonate• Prep: 1 mEq/mL in 50 mL syringe• IVP: 1.0 mEq/kg, then guided by ABG• Drip: 300 mEq/500 mL = 5% solution• Dose: Titrate to ABG

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Drips