ICU Drips

What is half-life of a drug?

The half-life of a drug is an estimate of the time it takes for the concentration or amount in the body of that drug to be reduced by exactly one-half (50%).

For example, if 100mg of a drug with a half-life of 60 minutes is taken, the following is estimated:

60 minutes after administration, 50mg remains

120 minutes after administration, 25mg remains

180 minutes after administration, 12.5mg remains

240 minutes after administration, 6.25mg remains

300 minutes after administration, 3.125mg remains.

In theory, after 300 minutes almost 97% of this drug is expected to have been eliminated. Most drugs are considered to have a negligible effect after four-to-five half-lives.

However, this does not mean that won't be detectable, for example, during a drug test. Just that the drug has no effect

Vassopressors

Epinephrine

Norepinephrine/Levophed

Phenylephrine/Neosynephrine Dopamine/Inotropin

Angiotensin II/Giapreza

Vassopressin/Vasostrict

N-PAVED

Sedatives

Lorazepam/Ativan

Propofol/Diprivan

Midazolam/Versed

Dexmedetomidine/Precedex

LM-PD

Antiarrhythmics

Amiodarone/Cordarone

*Diltiazem/Cardizem

Isoproterenol/Isopenaline

Brevibloc/Esmolol

Is a calcium channel blocker that slows heart rate in pts with a-fib, not antiarrythmic

Heart rate controlling medications

Beta blockers (-lol) (slows HR)

-Metroprolol

-Carvedilol

Calcium channel blockers (-ipine) (slow HR & reduce strength of contraction)

-Diltiazem (cardizem)

Digoxin

Heart Rhythm Controlling Medications

Sodium channel blockers

- Lidocaine

- Flecainide (Tambocor®)

- Propafenone (Rythmol®)

- Quinidine (Various)

Potassium channel blockers

- Amiodarone

Vasodilators

Nitroglycerine

Labetolol

Nicardipine/Cardene

Inotropics

- Change the force of contraction of your heart

There are 2 kinds of inotropes:

Given to what kind of patients

Milrinone/Primacor

Dobutamine/Dobutrex

- Positive inotropes strengthen the force of the heartbeat. (cardiomyopathy, CHF, recent MI)

- Negative inotropes weaken the force of the heartbeat and slow HR (HTN, CHF, arrhythmias, chest pain)

Examples of positive and negative Inotropics

Positive Inotropics

- Digoxin

- help the heart pump more blood with fewer heartbeats. This means that although the heart beats less, it also beats with more force to meet the oxygen demands of your body.

Negative

- beta-blockers, calcium channel blockers, and antiarrhythmic medicines

Neuromuscular Block

Nimbex/Cisatracuruim

Analgesic/Sedatives

Ketamine

Fentanyl

What are the two main benzodiazepines used in the ICU?

Lorazepam and midazolam are the two main benzodiazepines used for sedation in the ICU

Propofol is also used very often!

Lorazepam

Type

Use

Dose-Titration

Half-Life

Considerations

Benzodiazepine (Ativan)

Long term sedation and Intermittent therapy

1-8mg/hr infusion

Oral ~ 12 hours/IV ~ 14 hours/IM ~ 13-18 hours

Propylene glycol toxicity (especially with infusion); Delirium;

Preferred benzo in cirrhosis

Used in emergency situations involving seizures

Recommended for sustained sedation of mechanically ventilated

Midazolam

Type

Use

Dose-Titration

Half-Life

Considerations

Benzodiazepine (Versed)

Short term sedation or frequent neuro checks

1-10mg/hr; Titrate by 1mg every 30 minutes

3 hours (2-4)

Accumulates in adipose tissue; Unpredictable elimination; Less hypotension than propofol and dexmedetomidine.

Diprivan

Type

Use

Dose-Titration

Half-Life

Considerations

General anesthetic (Propofol)

Short term sedation or frequent neuro checks

5 mcg/kg/min; Titrate by 5 mcg/kg every 5 minutes . Max 80 mcg/min

used to help you relax or sleep before and during surgery or other medical procedures.

Dexmedetomidine

Type

Use

Dose-Titration

Half-Life

Considerations

Sedative/General anesthetic (Precedex)

Used for sedation of initially intubated and mechanically ventilated patients; Used before, during, and after intubation in mechanically vented patients

Initiate at 0.2 mcg/kg/hr; Titrate by 0.1 mcg/kg/hr every 15 minutes. Max 1.5 mcg/kg/hr

Distribution ~ 6 minutes; Terminal ~ up to 3 hours

Has some analgesic effects; Can cause hypotension and bradycardia; Intended for light sedation; Expensive

Can be used to sedate patient for general surgeries/procedures

Norepinephrine

Type

Use

Dose-Titration

Half-Life

Considerations

Levophed: Alpha/Beta Adrenergic Agonist

Acute hypotension. Sepsis and Septic shock. Preferred vasopressor in most situations.

5 mcg/minute Titrate by 1-5 mcg/minute every 5 minutes to maintain MAP above 65 mm/Hg. Don't exceed 30 mcg/minute

2.4 minute

Notify provider if/when dose reaches 30 mcg/minute. Do not exceed 80 mcg/minute. Maximum doese may be increased with prescriber order. May be especially necessary in obese patients (usual max: 60 mcg/min)

Pitressin

Type

Use

Dose-Titration

Half-Life

Considerations

Synthetic ADH (Vasopressin)

Usually 2nd line add-on to norepinephrine (esp. in septic shock)

0.04 units/min. DO NOT TITRATE.

10 to 20 mins

Should not be used alone initially but can be used alone once catecholamine agent weaned off; higher doses have risk for GI ischemia; is typically not titrated (on or off)

works on V2 receptors stimulating the RAAS system, which increases blood volume, cardiac output, and arterial pressure.

Angiotensin II

Type

Use

Dose-Titration

Half-Life

Considerations

Angiotensin II Agonists (Giapreza)

Septic or Distributive shock

Initiate at 20ng/kg/min. Titrate by 15ng/kg/min every 5 min to maintain MAP above 65mmHg.

< 1 minute

Do not exceed 80ng/kg/min in first 3 hours. After 3 hours, dose should not exceed 40ng/kg/min. Doses as low as 1.25ng/kg/min have been used

Dopamine

Type

Use

Dose-Titration

Half-Life

Considerations

Inotropic Agent (Inotropin)

Hypotension with bradycardia; Shock (cardio/septic)

Initiate infusion at 5mcg/kg/min. Titrate by 2.5mcg/kg/min every 5 min to maintain MAP above 65 mmHg. Do not exceed 20mcg/kg/min

2 minutes

High risk for arrhythmias at high doses; shown to lead to worse outcomes in cardiogenic shock.

Phenylephrine

Type

Use

Dose-Titration

Half-Life

Considerations

Alpha-Adrenergic Agonist (Neosynephrine)

Hypotension with tachycardia and preserved cardiac output; neurogenic shock

Initiate infusion at 40mcg/min. Titrate by 20 mcg/min every 10 mins to maintain MAP above 65 mmHg. Do not exceed 200mcg/min

Alpha phase 5 minutes; Terminal phase 2 to 3 hours

May be preferred in patients with severe tachycardia; provides no inotropic support' max dose may be increased with provider order

Epinephrine

Type

Use

Dose-Titration

Half-Life

Considerations

Alpha/Beta Adrenergic Agonist

Cardiogenic or anaphylactic shock; can be 2nd line agent for septic shock; often used as salvage therapy.

Initiate infusion at 5mcg/min. Titrate by 2.5mcg/min every 5 min to maintain MAP above 65 mmHg. Do not exceed 30mcg/min.

< 5minutes

Least selective vasopressor; reported to cause more GI hypo-perfusion compared to norepinephrine.

Amiodarone

Type

Use

Dose-Titration

Half-Life

Considerations

Antiarrhythmic (Cordarone)

Atrial and ventricular arrhythmias

1mg/min x 6 hrs. Then 0.5mg/min for 18hrs. Half-life: 9-36 days

Extremely long half-life

May cause heart block, bradycardia/hypotension; Hepatotoxicity

Diltiazem

Type

Use

Dose-Titration

Half-Life

Considerations

Calcium Channel Blocker (Cardizem)

Atrial Fibrilation

5mg-15mg/hr

3.4 Hours

Contraindicated in acute decompensated heart failure

Isoproterenol

Type

Use

Dose-Titration

Half-Life

Considerations

Beta 1/Beta 2 Agonist (Isoprenaline)

Mild or transient heart block; cardiogenic shock

If titrating, initiate at 2mcg/min. Titrate by 1mcg/min every 10 min to maintain HR greater than *** bpm. Do not exceed 10mcg/min

2.5 to 5 minutes

Avoid use in patients with distributive shock; may reduce systemic vascular resistance (SVR) further resulting in hemodynamic compromise. Use with caution in patients with cardiovascular disease (eg, coronary artery disease); may increase myocardial oxygen demand resulting in ischemia.

Milrinone

Type

Use

Dose-Titration

Half-Life

Considerations

Inotrope (Primacor)

Heart Failure exacerbation or other myocardial dysfunction (Sepsis, s/p CABG)

0.375-0.75mcg/kg/min

2.3 to 2.4 hours

Can be used in patients receiving beta-blockers; causes more hypotension than dobutamine; should be adjusted for renal dysfunction; can cause thrombocytopenia.

Used with caution in patients with renal dysfunction!

Dobutamine

Type

Use

Dose-Titration

Half-Life

Considerations

Inotrope (Dobutrex)

Heart Failure exacerbation or other myocardial dysfunction (Sepsis, s/p CABG)

2.5mcg-20mcg/kg/min

2 minutes

Should not be used in patients receiving beta-blockers; may cause hypotension (esp. septic patients)

Labetolol

Type

Use

Dose-Titration

Half-Life

Considerations

Beta-Blocker; Antihypertensive

Acute CVA; Aortic Dissection; Hypertensive

Emergency Initiate infusion at 1 mg/min. Titrate by0.5mg/min every 20 min to maintain SBP less than ** mmHg or MAP less than**.

Do not exceed 6mg/min.

5.5 hours

Long half-life titrate slowly to avoid overdose; use with extreme caution in patients with bronchospastic lung disease; contraindicated in acute heart failure

Nitroglycerine

Type

Use

Dose-Titration

Half-Life

Considerations

Vasodilator

Acute Coronary Syndrome; Pulmonary edema

Initiate at 5mcg/min. Titrate by 5mcg/min up to 20mcg/min. Above 20mcg/min, titrate by 10mcg/min every 5 min to maintain SBP less than ** or MAP less than **. Do not exceed 200mcg/min

1 to 4 minutes

Common side effect is headache-titrate slowly to decrease incidence; contraindicated with right ventricular failure

Nicardipine

Type

Use

Dose-Titration

Half-Life

Considerations

Calcium Channel Blocker; Antihypertensive (Cardene)

Acute CVA (pressure control); Hypertensive emergency.

Dosage/Titration (High/Low Dose): Initiate infusion at 5mg/hr. Titrate by 2.5mg every 5 min to maintain SBP less than ** or MAP less than **. Do not exceed 15mg/hr.

3 to 45 minutes; up to 14 hours (with long-term infusion)

Can cause rebound tachycardia; contraindicated in advanced aortic stenosis; commonly accompanied by high infusion rate; peripheral infusion site should be changed every 12 hours.

Ketamine

Type

Use

Dose-Titration

Half-Life

Considerations

General Anesthetic

Analgesia; Procedural sedation

0.2-0.5mg/kg/hr infusion

2.5 hours

Sympathomimetic effects (increase BP/HR). Psychotropic effects; Respiratory depression with high doses; Hypersalivation

Fentanyl

Type

Use

Dose-Titration

Half-Life

Considerations

Analgesic

Analgesia and sedation

Initiate infusion at 25mcg/hr. Titrate by 10mcg/hr every 15 min to maintain CPOT less than ***. Do not exceed 200mcg/hr

2 to 4 hrs

Monitor for respiratory depression, hypotension

Start Pressors early if after adequate fluid resuscitation MAP remains <65 mmHg.

Pressors can be started and continued peripherally until patient is stabilized.

What med should you start with? Which one second?

Start with norepinephrine first.

Consider adding vasopressin or epinephrine next.

Agents that can be used as third pressors: epinephrine, dobutamine, phenylephrine.

Dopamine increases the rates of arrhythmias and should be used judiciously.

Which is most commonly used for neurosurgical or spinal injury?

Phenylephrine

In severe Congestive Heart Failure exacerbations ionotropic agents such as ..... can be used?

In severe Congestive Heart Failure exacerbations ionotropic agents such as Dobutamine and Milnirone can be used, however due to their Beta-2 receptor stimulation, hypotension can worsen and concominant use of norepinephrine may be needed.

Types of shock (6)

Cardiogenic shock (due to heart problems)

eg: heart attack or Heart Failure

Hypovolemic shock (caused by too little blood volume) eg: Heavy external or Internal bleeding or dehydration

Anaphylactic shock (caused by allergic reaction)

Septic shock (due to infections)

Neurogenic shock (caused by damage to the nervous system)

Obstructive shock (caused by something outside of the heart which prevents the heart from pumping enough blood)

What is shock?

Is a life-threatening condition that occurs when the body is not getting enough blood flow.

Lack of blood flow means the cells and organs do not get enough oxygen and nutrients to function properly.

Many organs can be damaged as a result.

Shock requires immediate treatment and can get worse very rapidly.

As many as 1 in 5 people in shock will die from it.

SIRS vs Sepsis vs Severe Sepsis vs Septic Shock

Systemic Inflammatory Response Syndrome (SIRS), need 2/4 positive (NO INFECTION, just inflammatory response!)

a. Leukocytosis (WBC >12,000 ), Leukopenia or (<4,000)

b. Fever >100.4F OR Hypothermia < 96.8F

c. Tachypnea >20 breaths per minute

d. Tachycardia >90bpm

Sepsis: SIRS + Suspected Infection

-Ex: PNA, UTI, cellulitis, abd infection)

Severe Sepsis: Sepsis + Evidence of Organ Dysfunction

Septic Shock: Severe sepsis + hypotension DESPITE adequate resuscitation or Pressor requirement is needed

Septic shock occurs when a bacterial infection causes low blood pressure, widening of the blood vessels (vasodilation) and organ failure.

A wide spread infection that causes organ failure and low blood pressure

Systemic Inflammatory Response Syndrome

Examples of stressors

is an exaggerated defense response from your body to a harmful stressor. It causes severe inflammation throughout your body. This can lead to reversible or irreversible organ failure and even death.

Examples:

Infection

Surgery

Acute (sudden and severe) inflammation

Ischemia (lack of blood flow to an area of your body)

Cancer

Sympathetic nervous system causes

Pupils:

Heart:

Arteries:

Lungs/Airway:

Stomach/Intestine:

Bladder:

Pupil dilation

Increase heart rate

Peripheral arteries constrict

Coronary artery vasodilation

Relax Airways

Inhibit stomach and intestine activity

Relax bladder (decreased urine output)

Increased sweating

Pathways originate from thoracic and lumbar nerves

Two pathways:

Preganglionic nerve secretes ACh --> post ganglionic nerve that secretes NE (ganglion is where synapses of pre/post are)

Preganglionic nerve secrete ACh on Adrenal gland which secretes NE and E into the blood stream

What organ secretes epinephrine and norepinephrine?

The adrenal medulla, the inner part of an adrenal gland secrete epinephrine and norepinephrine directly into the bloodstream and arrive to target organs

Cholinergic receptors

Adrenergic receptors

two basic categories of receptors associated with the PNS

Cholinergic bind to ACh (2 types)

- Nicotinic (ionotropic=ion channel)

- Muscarinic (metabotrophic= G protein coupled receptor)

Adrenergic bind to NE/E (metabotrophic)

Parasympathetic

Pupils:

Heart:

Arteries:

Lungs/Airway:

Stomach/Intestine:

Bladder:

Pupil constriction

Slow heart rate

Peripheral arteries dilate

Coronary artery vasoconstriction

Constrict airway:

Stimulate activity of Stomach/Intestine

Contract bladder (increased urine output)

Pathways originate from cranial and sacral nerves

One pathway:

Long preganglionic nerve secretes ACh onto post ganglionic nerve which also secretes ACh