Trish Yaxley, LVT

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Technician's Guide to Nursing Care for Patients
with Cardiac Emergencies
Trish Yaxley, LVT Puget Sound Veterinary
Referral Center, PLLC 27th January 2008
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Definitions

• Afterload
• Cardiac output CO SV x HR
• Cardiogenic shock
• Contractility
• Preload
• Stroke Volume

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Definitions Continued

• Arterial pressure
• Bradycardia
• Tachycardia
• Diastolic BP
• Systolic BP
• Hyper/Hypotension
• Mean arterial pressure
  (SBP(2xDBP))/3

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Definitions continued

• Pleural effusion
• Pulmonary edema
• Tamponade
• Syncope

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Normal Cardiac Physiology

• Blood enters the heart via the vena cava
• Vena cava empties into the right atrium
• Right atrium empties into right ventricle via the
  tricuspid valve
• RV pumps blood via pulmonary artery to lungs

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Normal Cardiac Physiology

• Blood returns from lungs via pulmonary vein and
  empties into the left atrium
• Left atrium empties into left ventricle via the
  mitral valve
• Blood is pumped into circulation via the aorta
• Coronary arteries are fed from the aorta,
  ensuring the most oxygen rich blood for the heart
  muscle

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Cardiac Conduction

• Heart muscles shorten with electrical stimulation
• Sinoatrial node starts conduction and goes on
  following path atrioventicular node, bundle of
  his, bundle branches, and ending in Purkinje
  fibers.

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Receptors

• Receptors in the heart Beta (1)
• Receptors in blood vessels Alpha (1), Alpha
  (2), Beta (2) (also located in bronchi), and
  Muscarinic

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Pathophysiology

• Heart failure develops when chronic conditions
  cause the heart to work harder to pump blood
  continuously
• Mechanisms that make the heart pump harder
  include hypertension and increased blood volume

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Pathophysiology Ctd.

• The heart responds to the stress of having to
  pump harder by increasing the size of heart
  cells, called hypertrophy
• These muscle fibers will stretch to accommodate
  increased blood pressure and volume until they
  can no longer snap back effectively

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Pathophysiology Ctd.

• When the heart muscle is stretched too far it is
  unable to pump as strong as it used to and blood
  backs up in peripheral circulation and in the
  lungs causing edema and pulmonary edema.
• Other results include poor peripheral perfusion
  and systemic hypotension

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Goals

• By the time signs and symptoms are noticed, the
  disease has usually progressed to a point where
  the prognosis is poor.
• The goal of treatment is to control edema and
  manage blood pressure

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Normal Sinus Rhythm

• Characteristics Normal heart rate, with P, Q,
  R, S, and T waves all present.

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Atrial Fibrillation

• The atria are quivering because of a failure in
  conduction. There is no clear P wave and the
  base line is wavy because of irritable foci.
  There is an irregular heart rate.

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VPC or Ventricular beats

• Caused by irritable foci in the ventricles, these
  beats originate in the ventricles. They are
  large irregular complexes without P waves. The
  heart rate will be irregular. When there are
  more than one foci the VPCs will look different.

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Ventricular Tachycardia

• Many VPCs in a row without any atrial conduction.
  By definition, greater than 6 ventricular beats
  in a row is considered ventricular tachycardia.
  Treatment is commenced when the heart rate is
  sustained at a high rate and the patient becomes
  symptomatic. Treatment includes oxygen and
  anti-arrhythmic drugs.

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Ventricular Fibrillation

• The ventricle is quivering and no longer
  effectively pumping. This is considered a
  shockable rhythm, and will most likely be fatal
  if not treated as such. Other treatments include
  oxygen administration and anti-arrhythmic drugs.

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X-Rays
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Pulse Oximetry

• Good to have baseline if patient tolerates. Best
  readings come from tongue, however ears and
  between the pads can also bring adequate
  readings.
• Provides a measurement of how well the animal is
  perfusing and how well gas is being exchanged in
  the lungs.

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Blood Pressure
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Blood Pressure

• It is very important to get a baseline if the
  patient is stable enough.
• Heart rate means very little without a blood
  pressure, especially in a patient with
  cardiovascular compromise.
• It may be easier to obtain a blood pressure on a
  front limb because it is closer to the heart.
• Other ways to assess blood pressure include
  pulses, MM color, and CRT.

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Signs and Symptoms of Hypotension

• Pale mucous membranes
• Cold extremities
• Decreased level of consciousness
• Shallow rapid breathing
• Fatigue
• Thirst
• Fainting
• Nausea

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Signs and Symptoms of Hypertension

• May not be as noticeable as hypotensive signs
• Ocular changes
• Seizures
• Collapse
• Abnormal behavior

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CVP
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CVP

• Predictor of volume load.
• Patient has central line that is in right atria
• Line is connected to a monitoring device that
  measures pressures in cm of water.
• Goal for treatment of heart failure is to lower
  CVP by 4-5 cm of water.
• Most important thing about CVP is to keep the set
  up in the same position because CVPs are about
  trends

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Labs

• Increased BUN, Creatinine, and possibly liver
  values.
• Hyponatremia, hypokalemia
• Anemia
• Hyperthyroidism? Hypothyroidism?
• Hyperglycemia

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Assessment Signs and Symptoms
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JVD

• Jugular venous distentionUsually noted in right
  sided heart failure

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Dyspnea

• Note rate and involvement of chest and abdomen
  and the character of the respirations.
• Shallow rapid breathing is Kussmauls
  respirationsassociated with metabolic acidosis.
• Deep breathing with alternating periods of
  apnea-Cheyne-Stokes respirations-end stage
  manifestation.

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Bloody Sputum

• Pink frothy sputum is common with patients who
  have severe pulmonary edema

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Color

• Remember to assess baseline.
• Note changes with treatment and oxygen.
• Tongue color often changes first.
• Other areas to assess include eyes.

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Lung Sounds

• Need to assess often.
• Crackles most often assessed with patients who
  have pulmonary edema.
• Wheezes, harshness, stridor.

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Heart Sounds

• Murmurs
• Gallops
• Arrhythmias
• May not be present, however not a rule out for
  heart disease especially with cats.

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Cough

• History of cough especially at night or with
  exertion
• Accompanied with bloody sputum??

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Exercise Intollerance

• Noted in history-for how long?
• How much stress can the patient handle?

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Anorexia

• Manifestation of decreased cardiac output.
• May also note nausea and vomiting.

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Ascites

• Related to right sided heart failure.
• Can put pressure on the diaphragm causing
  increased dyspnea.

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Thromboembolsim

• The 5 Ps
• Pain
• Paresis
• Pallor
• Pulselessness
• Poikilothermy

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Signs and Symptoms of Hypokalemia

• Risk great with use of loop diuretics
• Mental disturbances
• Cardiac dysrhythmias (flattened T wave)
• Rapid, weak pulses
• Decreased BP
• Weakness
• Paralysis
• Muscle pain
• CatsVentroflexion of the neck

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Signs and Symptoms of Hyponatremia

• Nausea
• Vomiting
• Diarrhea
• Abdominal cramping
• Muscle tremors
• Twitching
• Weakness
• Confusion
• Seizures
• Coma

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Signs and Symptoms of Respiratory Alkalosis

• Early manifestation of heart failure.
• Patient will try to hyperventilate to facilitate
  gas exchange and gain more oxygen
• Confusion
• Syncope
• Tachypnea

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Signs and Symptoms of Metabolic Acidosis

• Late manifestation of heart failure.
• Decreased peripheral perfusion causes a build up
  of lactic acid causing MA.
• Nausea
• Vomiting
• General malaise
• Kussmauls respirations

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Interventions
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AVOID STRESS!!!
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Oxygen

• Cage or oxygen mask is preferred, some doctors
  prefer nasal oxygen.
• Flow by oxygen can be used if mask oxygen is too
  stressful while treating pets.

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Positioning

• Position sternally
• Important to prop sternally because it is the
  position that facilitates oxygenation and allows
  the patient maximal inflation of lungs.

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IV Catheter

• Do as soon as patient is stable enough.
• Provide oxygen!!
• Use a moderate sized catheter.
• Use cephalic when able (easy access).
• Jugular catheter to monitor CVPs when indicated.

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Intravenous Fluids

• Indications Cardiogenic shock, dehydration,
  drug induced hypotension, renal failure,
  hypokalemia, anorexia, vomiting, concurrent
  metabolic or infectious disease, need of a
  vehicle for constant rate of infusion

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Special Monitoring of IVF

• Body weight q12h
• MMs (note dependence on O2)
• Pulse rate and quality
• RR and effort
• LUNG SOUNDS
• HEART SOUNDS
• Rate and volume
• Urine output (1-2 ml/kg/hr)
• Blood pressure
• CVP

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DRUGS

• Important to understand drugs action, the reason
  for administration, and side effects.
• What do you need to know before administering the
  medication??
• Actions can work against you..

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Furosemide

• Works directly on kidneys to decrease the
  resorption of sodium and chloride and
  subsequently decreasing blood volume.
• Reduction of volume reduction in BP.
• Baseline BP or pulses and CRT if patient is not
  stable.
• Always provide water
• May not work well if patient has kidney
  dysfunction
• Lose potassium!!!

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Thiazide Diuretics

• Not used often in veterinary medicine
• Prevents the reabsorption of sodium and chloride
  (and thus water) back to peripheral circulation.
• Lowers BP and Potassium, so...

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ACE Inhibitors

• Review Renin-Angiotensin-Aldosterone.
• ACE Inhibitors prevent the conversion of
  angiotensin I to II
• Causes vasodilation and decreased BP
• ENALAPRIL, benazapril
• So..

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Beta Blockers

• Block effects on beta adrenergic receptors
• Review Beta (1) receptors increase HR (AV
  conduction), beta (2) receptors dilate smooth
  muscle and bronchial tree
• Older drugs arent selective for (1) so they can
  cause vasoconstriction and bronchoconstriction
• Propranolol stablizes membranesanti-arrhythmic
• Know HR, BP, Hx of airway dz???

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Calcium Channel Blockers

• Stop the slow calcium channels in the heart and
  to a greater degree in peripheral vasculature.
• Effect Vasodilation and decreased HR, decreased
  afterload.
• Know BP, HR.
• NORVASC, DILTIAZEM

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Pimobendan

• New drug
• Increases both contractility and as vasodilator
  effects
• Increases calcium sensitivity in the cardiac
  contractility apparatus and inhibiting
  phosphodiesterase.
• Effect venous and arterial vasodialation and
  decreased HR.
• Know BP and HR.

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Digoxin

• Positive Ionotrope
• Increases contractility of the heart
• May also have diuretic effects
• Has anti-arrhythmic effects
• Major side effects Bradycardia and Hypokalemia
• Need to monitor serum levels

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Dobutamine

• Beta (1) agonist
• Structurally similar to dopamine
• Positive Ionotropic agent
• Effect Increased stroke volume and cardiac
  output
• BP and HR increase slightly
• Used short term to treat to restore arterial
  blood pressure, CO, and perfusion with patients
  in cardiogenic shock
• Continuously monitor HR and BP

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Dopamine

• A catecholemine (neurotransmitter like
  epinephrine)
• At low doses it dilates renal arteries as well as
  mesentaric, coronary and intracerebral beds
  (promotes perfusion)
• Higher doses used for shock and works by
  vasoconstriction (opposite of low dose)
• Nursing actions include BP monitoring and urine
  output
• New studies out saying that cats dopamine
  receptors are not as effective making dobutamine
  the drug of choice for cats

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Nitroglycerin

• Vasodilator, especially of coronary arteries.
• Used in severe cases of CHFlowers BP
• Nursing actions BP, watch for signs and
  symptoms of hypotension.
• Often administered on the skin of the abdomen or
  chest, cover with tape so that no one touches
• Wear gloves and use the ruler provided when
  applying to prevent overdosing patient.
• If any gets on your handswash right away!!

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Nitroprusside

• Relaxes smooth muscle and causes vasodilation
• IV drip medication
• Need to cover bag and line
• Can cause severe hypotensionCONSTANT BP
  MONITORING!!!
• Can give drip in very small amounts of fluid

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Aspirin

• Platelet aggregation inhibitor.
• Used in patients who have coagulopathies and are
  throwing clots.
• Aspirin works by inhibiting prostaglandins COX-1
  and 2.
• This causes good effects of not sticky platelets,
  and pain/fever reductionsas well as bad effects
  of inhibiting the GI protective factors that
  these prostaglandins are responsible for.
• Note platelet counts before adminsitering

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Amiodarone

• Anti-arrhythmic drug
• Used when a patients ventricular tachycardia is
  refractory to other treatment such as oxygen,
  lidocaine, and propranolol
• Need to monitor heart rate and rhythm as well as
  BP

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Lidocaine

• Anti-arrhythmic
• Generally first line for control of V-Tach.
• Monitor ECG and BP continuously if administering
  in CRI

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Atropine

• Usually associated with CPR/crashing animals
• Used sometimes with bradyacardia and heart blocks
• Action Blocks cholinergic (parasympathetic)
  receptors and increases heart rate.
• Also associated with drying secretions, and
  decreased GI motilitybe sure that your patient
  doesnt have an obstruction!
• Important to give adequate doselow doses can
  actually perpetuate bradycardia
• Nursing actions include ECG and BP monitoring

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Other Medication Notes

• Avoid Ketamine with heart patients
• Butorphanol and Buprenorphine are both fairly
  safe and effective to help calm anxious patients
  and provide pain relief. Cats could especially
  benefit from these medications