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Caring for patients receiving vasopressors and inotropes in the ICU

Vigilant will maximize outcomes.

By Sonya M. Grigsby, DNP, APRN, AGACNP-BC

CNE 1.5 contact hours LEARNING O BJECTIVES 1. Identify receptors related to cardiovascular physiology. 2. Differentiate the effects of vasopressors and inotropes. 3. Discuss nursing care of patients receiving vasopressors and inotropes in the ICU.

The authors and planners of this CNE activity have disclosed no relevant fi- nancial relationships with any commercial companies pertaining to this ac- tivity. See the last page of the article to learn how to earn CNE credit.

Expiration: 2/1/24

SHOCK requires early recognition and quick peutic effect) these using the action to prevent organ failure. (See Types of lowest possible dose to avoid adverse effects. .) After initial I.V. fluid , pharmacologic agents—such as vasopressors Cardiovascular physiology and inotropes—are used in critical care set- Shock disrupts cardiovascular physiology, par- tings as supportive therapies to improve my- ticularly , so understanding ocardial contractility, rate, and vascular normal function is important. Short-term resistance in patients with low . blood pressure (BP) regulation is controlled When critical care nurses understand shock by the autonomic nervous system (ANS) via pathophysiology and hemodynamic monitor- baroreceptors in the aortic arch and carotid si- ing, they can effectively and safely titrate (in- nus. The ANS regulates the heart, secretory crease or decrease an infusion rate for thera- glands, and smooth muscles via activation of

MyAmericanNurse.com February 2021 American Nurse Journal 5 Types of shock

Shock is a decline in tissue and oxygen delivery, leading to cellular dysfunction and death. Organ hypoperfusion results from decreased circulating volume (hypovolemic shock), decreased cardiac their physiologic response. Other receptors are output (cardiogenic and obstructive), and (distributive). vasopressin (V1 and V2; this article focuses on V1) and . (See Receptor physiology.) Types of shock Common causes Adrenergic receptors. a1 receptors are Hypovolemic • Hemorrhage located within the veins, arterioles, and many • Emesis capillary beds. When stimulated, they pro- • Diarrhea duce . a2 receptors also are lo- • Burns cated on the nerve terminals of the peripheral • Third spacing (too much fluid moving from the nervous system and function to inhibit trans- intravascular space into the interstitial space) mitter release. • Polyuria Beta receptors are found on the arterioles

• of the heart, smooth muscle tissues, and the Cardiogenic lungs where they bind to circulating norepi- • nephrine and epinephrine. b1, the dominant • Valvular diseases • Arrhythmias receptor found in the heart and kidney, en- • hances and relaxation when it’s activated. It also increases Obstructive • Tension pneumothorax and cardiac output. Systemic vasodilation may • Pulmonary embolism offset increased cardiac output, resulting in • Air embolism decreased arterial pressures. b1 receptor acti- • Cardiac tamponade vation in the kidneys induces the release of • renin into the blood, promoting

• synthesis and elevating BP. b2 receptors, Distributive Anaphylaxis which are located in the arterioles of the • Neurologic condition (such as spinal cord trauma) heart, smooth muscle tissues, and lungs, help • mediate many essential processes. Although b2 receptors cause vasodilation, their effect on the parasympathetic and sympathetic systems. cardiac output is less than that of b1. In addi- Body processes activate the ANS in response tion, b2 receptors have a significant impact on to information produced by internal and ex- smooth muscles in the airway and cause bron- ternal stimuli, including blood pressure, body chodilation. temperature, heart rate, respiratory rate, me- Dopamine receptors. Site-specific dopa - tabolism, urination, defecation, digestion, and mine receptors also exert cardiovascular sexual response via chemical and neurotrans- actions. Small doses of dopamine result in mitter signaling. vasodilation. As activation increases, vaso- The sympathetic system prepares the body constriction occurs via stimulation of a1 re- for stressful or emergent situations, resulting ceptors and inhibition of norepinephrine re- in increased heart rate and contractility, vaso- lease. Dopamine receptor activation within constriction, and norepinephrine and epi- the kidney vasculature leads to enhanced re- nephrine release, which increase BP. The nal perfusion. parasympathetic system conserves and re- Vasopressin receptors. Arginine vaso- stores body processes during normal condi- pressin, an antidiuretic hormone, is synthe- tions, resulting in reduced heart rate, cardiac sized in the hypothalamus and controls the output, and BP. body’s osmotic balance, regulates BP, and in- fluences water reabsorption in the kidneys. V1 Receptors receptors are found in vascular smooth mus- Adrenergic receptors (which affect the sympa- cles. Their stimulation results in vasoconstric- thetic nervous system) within the heart and tion, primarily in the splanchnic, renal, and vascular system facilitate the hemodynamic ef- hepatic arteriole vasculature. Hypovolemia fects of vasopressors via the interaction of cat- and decreased arterial stimulate echolamines and synthetic medications such vasopressin release via baroreceptors in the as norepinephrine and epinephrine. Adrener- carotid sinuses and aortic arch, resulting in gic receptors are classified as alpha (a1, a2) or increased water retention that causes vascular beta (b1, b2), and their location determines smooth muscle constriction.

6 American Nurse Journal Volume 16, Number 2 MyAmericanNurse.com Receptor physiology

Adrenergic (alpha and beta), dopamine, and vasopressin receptors exert actions on specific organs. Supportive pharmacologic therapies Vasopressors and inotropes are commonly Receptors Location Action used in the ICU to manage shock and support Adrenergic α1 • Smooth muscle • Vasoconstriction the cardiovascular system. (To view a detailed • Vascular walls • Increased force of list of common vasopressors and inotropes, • Heart heart contraction visit myamericannurse.com/?p=71893.) Vasopressors. Vasopressors are I.V. med- Adrenergic α2 • Central nervous system • Sedation ications that produce arteriole vasoconstric- • Arterioles • Analgesia tion via positive inotropic or ef- • Pancreas • Vasodilation fects that lead to increased systemic vascular • Inhibition of resistance and BP. Common vasopressors are release norepinephrine, epinephrine, phenylephrine, • • and vasopressin. Indications include a de- Adrenergic β1 Cardiac muscle Increased force and • Sinus node rate of heart crease in systolic pressure of more than 30 • Atrioventricular junction contraction mmHg from baseline or mean arterial pres- sure (MAP) less than 60 mmHg resulting in Adrenergic β2 • Skeletal vascular • Vasodilation end-organ dysfunction. (MAP, the average • Bronchial smooth muscle • Bronchodilation pressure in the arteries during one cardiac cy- • Liver • Hepatic cle, is the best indicator of organ perfusion.) • Cell membranes glycogenolysis Vasopressors work on specific adrenergic receptors by activating endogenous or syn- Dopamine • Kidney • Vasodilation thetic hormones to restore normal arterial • Splanchnic organs • Higher receptor • Heart activation causes pressure and organ perfusion during times of • physical or emotional stress. Cerebral vascular beds vasoconstriction by inhibiting Inotropes. Inotropes, which are crucial to norepinephrine resuscitating patients with release and , can exude positive or nega- tive effects on the heart. Positive inotropic Vasopressin • Vascular smooth muscle • Vasoconstriction agents, which include dopamine and dobuta- mine, increase myocardial contractility, boost- ing cardiac output. These agents have been electrocardiogram, temperature, respiratory used to treat heart failure, but variability in rate, oximetry, and urine output. conditions and heart rate may alter their ef- Invasive monitoring includes inserting an fects. Adverse reactions associated with posi- for continuous BP measurement tive inotropic agents include arrhythmias, in- and arterial blood gas analysis, and central ve- duced myocardial ischemia, and hypotension. nous catheterization or Negative inotropic agents, which include beta catheters (PACs) for advanced hemodynamic blockers and calcium blockers (such as meto- monitoring to guide fluid resuscitation and the prolol, , and ), decrease the need for vasopressors or inotropic infusions. heart’s workload by reducing the force of Both invasive and noninvasive monitoring ; they are outside the scope are helpful for assessing patients’ responses to of this article. medications, so that titration is effective. Here is a closer look at invasive techniques used for Hemodynamic monitoring and monitoring and administration. medication administration Hemodynamic monitoring involves using in- Arterial catheterization vasive and noninvasive methods to gather in- Vasopressor and inotropic drugs act quickly, formation about a critically ill patient’s cardio- so invasive BP monitoring, typically by arterial vascular functioning for diagnosis and catheterization, may be required to safely treatment guidance. Hemodynamic instability titrate vasopressor and inotrope infusions. Ar- can be the result of hypovolemia or cardiac or terial catheterization also provides access for vasomotor dysfunction, which can lead to or- diagnostic laboratory blood testing. gan dysfunction, multi-organ failure, or death. A trained provider places the arterial line Noninvasive monitoring includes manual BP, using sterile technique. Radial and femoral

MyAmericanNurse.com February 2021 American Nurse Journal 7 from a “fast flush.” If the waveform is ade- quately dampened, only two oscillations fol- low the flush with a subsequent clear arterial waveform and a visible dicrotic notch. Waveform dampening also can result from kinked or obstructed cannulas, loose connec- tions, and air bubbles within the tubing or transducer, resulting in false low or high read- Arterial line complications and ings. Inaccurate and misinterpreted wave- nursing considerations forms can affect infusion titrations and clinical endpoints. Arterial line complications can cause serious harm to patients. Arterial line complications include severe • Loose connections can lead to massive blood loss if undetected. blood loss, local or systemic infections, arteri- Check for a dampened waveform or unusually low pressure reading, al thrombosis, air embolism, and accidental which may indicate a loose connection. medication injection. (See Arterial line compli- • Catheters placed in the radial artery can damage the radial nerve. To cations and nursing considerations.) prevent injury, place an arm board to facilitate proper alignment. • Hand ischemia or digital embolization may occur with lines placed Central venous catheterization in the radial artery. These complications may be caused by thrombo- Central venous catherization (CVC) allows for sis, so don’t force flush the line, which may prove fatal. central venous access using one of three op- tions: the internal jugular vein, common femoral vein, or subclavian vein. CVC is used sites are the most common, but other loca- for multiple infusions, if peripheral access tions include the brachial, axillary, and dor- can’t be obtained, and to administer medica- salis pedis artery. As the critical care nurse, tions that may be caustic to tissues when giv- you’re responsible for arterial transducer set- en via peripherally inserted catheters. up (including leveling) line patency, hemody- Vasoactive infusions through a peripherally namic response assessment using arterial inserted venous catheter may cause severe tis- waveform interpretation, and insertion site sue injury and necrosis with infiltration. Con- care. Transducer setup requires tight tubing troversy exists over the absolute need for a and catheter connections, a pressure bag set instead of a peripher- at 300 mmHg to maintain system patency, and ally inserted one to administer vasopressor a transducer leveled to the phlebostatic axis. and inotrope infusions. Considerations include The phlebostatic axis is located at the conver- drug concentration, infusion rate, and dura- gence of a vertical line drawn from the fourth tion. However, the absence of central access intercostal space to the right of the sternum shouldn’t hinder the initiation of these drugs, midway from the anterior to the posterior as failing to initiate therapy promptly could re- chest. Mark the site to ensure consistency for sult in detrimental effects to the patient. If cen- accurate pressure readings. Transducer level- tral access isn’t available, initiate the infusion ing should be performed every shift or when- at the lowest rate and concentration necessary ever a data discrepancy occurs. to achieve directed hemodynamic goals, and The arterial line is a continuous measure- carefully monitor the peripheral site. ment of heart rate, BP, systemic perfusion, If infiltration is suspected, immediately dis- MAP, , and pulse pressure vari- continue the infusion, aspirate any residual fluid ation. Arterial waveforms represent left ven- from the catheter, irrigate the line with saline, tricular pressure during and consist of elevate the affected area, apply warm or cold three components: systolic phase (steep rise compresses per protocol, and notify the phar- in arterial pressure from the lowest point to macy and provider. Pharmacologic treatment the peak), dicrotic notch (closure of the aortic for infiltration of vasopressors and inotropes in- valve), and the diastolic phase (lowest point). cludes subcutaneous administration of 5 to 10 The Square Wave Test ensures accuracy of mg of phentolamine mesylate in 10 mL of saline the hemodynamic values. It’s performed by around the infiltration within 12 hours of ex- opening the continuous flush valve to a high- travasation to prevent local ischemia. pressure signal, invoking transducer vibration To prevent intravascular catheter-related in-

8 American Nurse Journal Volume 16, Number 2 MyAmericanNurse.com PAC ports

Critical care nurses should be familiar with the pulmonary artery catheter (PAC) port colors and their associated purposes. fections, the Centers for Disease Control and Prevention recommends using aseptic tech- Port Purpose nique when changing dressings and prompt re- Yellow • Measures pulmonary artery/pulmonary artery moval when the catheter is no longer needed. (PA distal) wedge pressures • Can be used to draw specimens for mixed Pulmonary artery catheterization venous gases PAC (Swan-Ganz catheter) has been the gold standard for cardiac output monitoring for White • Infusion/injection of I.V. fluids and nearly 50 years, primarily in cardiac surgery (proximal infusion) medications patients. The PAC is inserted through a central Blue • Measures vein (femoral, jugular, antecubital, or brachial) • and advanced through the right side of the (proximal injectate) Can be used for infusion/injection of I.V. fluids heart to the pulmonary artery. It’s used to and medications measure intrathoracic intravascular pressures Red • Measures pulmonary artery wedge pressure in the right atrium (central venous pressure), (wedge) pulmonary artery, and pulmonary veins (pul- monary wedge pressure). A PAC is particularly Yellow/red cap • Measures temperature at tip of pulmonary helpful in patients with right ventricular dys- (thermistor) artery function or pulmonary arterial hypertension. Routine PAC site care requires following or- ganization policy for sterile dressing changes must be administered via infusion pump to and documenting catheter placement and signs prevent interrupted flow, unexpected changes and symptoms of site infection. The catheter’s in flow rates, and undesired boluses. Vaso- sterile sleeve integrity must be maintained to pressors have a short half-life and duration of allow catheter movement without contamina- action, so they require continuous infusion tion. In addition to site care, monitor for dys- and rapid titration, usually every 5 to 15 min- rhythmias, check waveform and hemodynamic utes. You want to find a balance between values, oversee patient activity and positioning, hemodynamic stability and adequate perfu- and remove the catheter as ordered. sion while using the minimum dose needed. Assessing patients with a PAC is essential When hemodynamic stability has been for preventing and identifying potential com- achieved, begin weaning vasopressors to fa- plications, including balloon rupture, dys- cilitate the lowest dose required to maintain rhythmias, air embolism, pulmonary thrombo - the desired effects. embolism, pulmonary artery rupture, and Your familiarity with organizational and infarction. Review daily chest imaging to unit titration policies will help ensure patient check catheter position, and zero and level safety and reduce medication error and ad- transducers after repositioning. Spontaneous verse event risks. Smart pumps can help re- balloon wedging is life-threatening and re- duce medication errors, but you must calcu- quires immediate intervention. Ensure the late and verify infusions before administration wedging syringe isn’t full of air or accidentally and confirm minimum and maximum doses. inflated and that the balloon is deflated. (See PAC ports.) Knowledge and competency Hemodynamic monitoring and vasopressor Vasopressor and inotropic infusion and inotrope administration and titration are titration essential to ensuring sufficient tissue oxygena- When the initial vasopressor or inotrope has tion and end-organ perfusion. Your knowledge been selected based on the underlying cause of anatomy, physiology, and pharmacology, of shock, titrate the dose to achieve sufficient along with competent assessment skills, can blood pressure or end-organ perfusion indi- ensure a safe outcome for your patients. AN cated by the MAP, as ordered by the provider. The most common target for vasopressor and To view a list of references, visit myamericannurse.com/ ?p=71893. inotropic titration is a MAP value of 60 mmHg to 65 mmHg. Sonya M. Grigsby is a critical care advanced practice RN at Christus Continuous vasopressor/inotropic infusions Mother Frances Hospital in Tyler, Texas.

MyAmericanNurse.com February 2021 American Nurse Journal 9

POST-TEST • Caring for patients receiving vasopressors and inotropes in the ICU CNE: 1.5 contact hours CNE Earn contact hour credit online at myamerciannurse.com/vasopressors-inotropes-icu

Provider accreditation Contact hours: 1.5 The American Nurses Association is accredited as a provider ANA is approved by the California Board of Registered Nurs- of nursing continuing professional development by the ing, Provider Number CEP17219. American Nurses Credentialing Center’s Commission on Post-test passing score is 80%. Accreditation. Expiration: 2/1/24

Please mark the correct answer 7. The phlebostatic axis is located at c. As ordered, administer 10 to 20 online. the convergence of a vertical line mg of phentolamine mesylate in drawn from the 10 mL of saline around the infiltra- 1. Effects of the parasympathetic tion. nervous system include a. fifth intercostal space to the right of the sternum midway from the d. As ordered, administer 5 to 10 mg a. increased contractility. anterior to the posterior chest. of phentolamine mesylate in 10 b. vasoconstriction. b. fourth intercostal space to the mL of saline around the infiltra- c. reduced heart rate right of the sternum midway tion. d. higher blood pressure. from the anterior to the posterior chest. 11. Which port of a pulmonary artery catheter is used to measure pulmonary 2. Vasopressin receptors are located in c. fourth intercostal space to the artery pressure? a. splanchnic organs. left of the sternum midway from b. cerebral vascular beds. the anterior to the posterior a. Injectate c. vascular smooth muscle. chest. b. Thermistor d. bronchial smooth muscle. d. third intercostal space to the c. Distal right of the sternum one-third d. Proximal 3. When activated, which receptor away from the anterior to the type causes inhibition of insulin re- posterior chest. 12. At which infusion rate does lease? dopamine produce vasoconstriction? 8. The dicrotic notch in an arterial a. Adrenergic α2 a. More than 10 mcg/kg/min waveform represents b. Adrenergic β2 b. More than 7 mcg/kg/min a. closure of the mitral valve. c. Dopamine c. 1 to 3 mcg/kg/min b. closure of the aortic valve. d. Vasopressin d. 4 to 6 mcg/kg/min c. opening of the pulmonary valve. 4. When activated, which receptor d. opening of the tricuspid valve. 13. An inotropic agent that is a first type causes bronchodilation? drug of choice for cardiogenic shock is 9. Which of the following statements a. Adrenergic α2 a. . about arterial waveform dampening is b. Adrenergic β2 correct? b. . c. Dopamine a. In the Square Wave Test, it should c. epinephrine. d. Vasopressin be followed by three oscillations. d. vasopressin. b. In the Square Wave Test, it should 14. Mesentery ischemia is a possible 5. An example of a positive inotrope is be followed by four oscillations. adverse effect for which drug? a. diltiazem. c. It can be caused by air bubbles a. Dobutamine b. . within the tubing or transducer. b. Dopamine c. verapamil. d. It does not affect drug infusion d. dopamine. titrations or clinical endpoints. c. Phenylephrine d. Vasopressin 6. Indications for use of a vasopressor 10. You suspect infiltration in a patient in a patient experiencing shock include who is receiving a dopamine infusion a. decrease in systolic pressure of through a central venous catheter. more than 30 mmHg from base- Which is an appropriate step? line. a. Monitor the site for 4 hours to de- b. decrease in systolic pressure of termine severity, then flush with more than 40 mmHg from base- saline. line. b. If the infusion is in the femoral c. less than vein, place the leg in a dependent 80 mmHg. position. d. mean arterial pressure less than 90 mmHg.

10 American Nurse Journal Volume 16, Number 2 MyAmericanNurse.com