Blue and Bluer in I'R'

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Blue and Bluer in I.R.

• Lisa M. Montenegro, MD
• Division of Cardiac Anesthesia
• The Cardiac Center at
• The Childrens Hospital of Philadelphia

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orSedation and Anesthesia for Non-cardiac
Procedures in Patients with Congenital Heart
Disease
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Why does this topic cause so much discussion?

• Great diversity of anatomic and physiologic
  perturbations
• well and unwell states
• affects every organ system
• Cardiovascular and pulmonary capacity may be
  quite limited
• Little objective data about an optimal
  anesthetic or sedation plan

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In the beginning
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Why discuss this at all?

• Patients are living longer
• Patients are developing special problems related
  to their heart/lung disease
• Patients are also living long enough to have
  regular problems
• Sometimes its us, and sometimes its you!

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Causes of Cardiovascular Impairment

• Primary cardiac diagnosis
• Hypoxemia
• Pulmonary disease
• Cardiac failure
• Rhythm disturbances
• (and other comorbidities)

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Hypoxemia

• Associated with decreased pulmonary blood flow
  and/or right -gt left shunting

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Chronic Hypoxemia

• BAD!
• Affects all organ systems
• Blue people may also have cardiac or pulmonary
  dysfunction, or rhythm disturbances or not!

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Does this sound like a no-win situation?!
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(No Transcript)
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Physiologic Responses to Hypoxemia

• Increased respiratory rate
• Decreased mixed venous saturation
• Increased cardiac output (transient if at all
  possible)
• Long-term polycythemia

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Stress Conditions

• Highlight the frailty of the compromised heart

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Beware of the Blue!

• The older and bluer the patient, the more likely
  that there is underlying compromise of cardiac
  function
• Anticoagulation therapies
• Association with clotting abnormalities
• thrombocytopenia
• platelet dysfunction
• hypofibrinogenemia
• liver dysfunction
• Hyperviscosity concerns
• ?NPO?

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Most Common Abnormalities

• Elevated PT or PTT
• Commonly associated with Hct gt65

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Pulmonary Disease

• Pulmonary hypertension
• Chronic ventilation
• Polycythemia associated with microemboli in
  microvasculature
• Intrapulmonary shunts (i.e. AVMs)

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Pulmonary Hypertension

• Right heart failure
• Very sensitive to changes in PVR
• Sedation can change PVR (not good)
• Very hard to resuscitate

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Who are these patients?

• Preemies
• BPD-ers
• Spell-ers

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Cardiac Failure

• The older and bluer, the more likely that there
  is some cardiac compromise
• This may not become apparent until the patient is
  stressed (as in IR or the OR!)
• Exercise intolerance is a good clue that there is
  some compromise of cardiac function

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Rhythm Disturbances

• More common over time
• Fontan and TGA
• Prolonged QT syndrome

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What words should ring a bell?

• Fontan
• Single ventricle
• Pulmonary hypertension
• Dopamine and Milrinone
• Sildenafil
• PICC line

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Anesthesia/Sedation Considerations

• Preoperative assessment
• exercise tolerance
• feeding intolerance
• Know meds especially ASA, Lovenox, Plavix and
  heparin
• Delayed gastric emptying
• ? Need for SBE prophylaxis

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Special Considerations

• Hydration, hydration, hydration!
• Many children with heart disease, especially
  those with single ventricle physiology, are fully
  preload dependent for cardiac output. Their
  hydration status will directly affect their
  ability to tolerate sedation.

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Fluid Considerations

• Bubbles, bubbles, bubbles!

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Single Ventricle Physiology

• Normally, blood flows in parallel circulation
• In single ventricle, blood flows in series.

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HLHS
1. Hypoplastic ascending aorta and aortic arch.
2. Hypoplastic left ventricle. 3. Large patent
ductus arteriosus supplying the only source of
blood flow to the body. 4. Atrial septal defect
allowing blood returning from lungs to reach the
single ventricle.
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Imagine youre a red blood cell

• You travel down the SVC (or up the IVC) DIRECTLY
  to the pulmonary artery.
• Do not enter the heart, do not collect 200.
• Travel through the lungs and get oxygenated
• Return to the atrium, go to the ventricle, out
  the aorta to the bodythrough capillaries to the
  SVC or IVC and around again!

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If there isnt enough circulating volume

• The pressure gradient across the lungs decreases
• There isnt enough volume coming back to the
  ventricle to pump to the body
• Cardiac output decreases
• The patient gets bluer
• The cycle is hard to break

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Transposition of the Great Arteries
1. Aorta arising from the right ventricle.
Poorly oxygenated blood is delivered to the body.
2. Pulmonary artery arising form the left
ventricle. Well oxygenated blood delivered back
to the lungs.
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Tetralogy of Fallot
1.Right ventricular outflow obstruction. 2.
Right ventricular hypertrophy (thickened muscle
wall) 3. The aorta "overrides" the VSD. 4.
Ventricular septal defect.
5. Muscular right ventricular outflow obstruction
has been cut away as part of the repair. 6.
Patch closure of the VSD.
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Premedication

• Benefits can outweigh risks
• Secretions
• Catecholamine surge, especially with compromised
  cardiac function
• Consider an antisialogogue

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Primary Goal

• Maintain adequate tissue oxygenation

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• Choice of anesthetic agents is less important
  than maintaining hemodynamic stability.

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Less is More!
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Sedation vs GA Conscious Sedation

• Patients maintain airway protective reflexes
• Can respond appropriately to requests

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Sedation vs GA Deep Sedation

• Patient is not easily arouse-able
• Airway protective reflexes may or may not be
  intact
• Increased risk of airway obstruction and/or
  aspiration

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Sedation vs GAGeneral Anesthesia

• Controlled state of unconsciousness
• Loss of airway protective reflexes

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Monitoring

• ECG
• Pulse oximetry
• NIBP (or invasive if required)
• Temperature
• Capnograph?

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Monitoring

• Includes appropriate post-sedation care

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Drugs - Midazolam

• Benzodiazepine
• Short-acting
• Titratable
• Antegrade amnesia
• Respiratory depression
• Reversible
• (?) hemodynamic stability (?)

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Drugs - Fentanyl

• Narcotic
• Titratable
• Reversible
• Respiratory depression
• Synergistic effects with benzodiazepines
• (?) hemodynamic stability (?)

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Drugs - Ketamine

• Dissociative anesthetic
• Potent analgesic
• Hemodynamic stability (?)
• Tachycardia
• Rhythm disturbance
• (?) respiratory depression

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Drugs - Etomidate

• Etomidate has anesthetic and amnestic properties,
  but has no analgesic properties
• Etomidate is commonly used as part of a rapid
  sequence induction to induce anesthesia or for
  conscious sedation.
• Rapid onset of action and a low cardiovascular
  risk profile, and therefore is less likely to
  cause a significant drop in blood pressure than
  other induction agents.

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Drugs - Pentobarbital

• Barbiturate
• Longer-lasting
• Titratable
• NOT reversible
• (?) repsiratory depression (?)

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Drugs - Propofol

• Delivered by infusion
• Natural airway or breathing tube
• Easily titratable

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Pentothal

• Why not?

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New drugs Dexmedetomidine and Remifentanyl

• Delivered by IV infusion
• Easily titratable
• Very short half-lives
• Natural airway or ETT
• Great analgesia
• Respiratory depression can be seen

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ALL SEDATIVE AGENTS

• Myocardial depressants
• Remove normal responses to hypercarbia and
  hypoxemia

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Case Discussion

• 12 year old s/p Fontan for T/A or PICC
• Add-on case
• Anxious
• Late in day
• NPO!

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Concerns

• Age
• NPO status
• to drink or not to drink
• Preload-dependent
• Timing of elective procedure
• Physiologic concerns
• ventricular function
• filling pressures
• coagulopathy

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NEVER hesitate to call

• earlier is better in everything!

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THANK YOU!