Transcript Post-Operative Care of the Pediatric Heart Surgery Patient

Post-operative Care in Pediatric
Open-Heart Procedure
Herbert G. Uy MD FAAP
Pediatric Critical Care Medicine
Systems important in
postoperative cardiac
management
• CNS
• Cardiovascular
• Pulmonary
• Renal
• Pain Control
• Nutrition
Central Nervous System
• Monitor
– Sensorium
– Pupils
– Reflexes
– Movement
(symmetrical or
not)
– Sensory
• Sedated?
Central Nervous System
• Morbidity?
– Difficult Surgery
– Unstable condition prior to surgery
– Bypass complication
Cardiovascular - Basic
Preload
• Amount of volume filling ventricles
during diastole
• Proportional to volume status
• Increasing preload, increases
stroke volume (in general)
• Monitor Preload using CVP,RAP,
LAP
Preload Problems in post-op
Patients
Either there is not enough preload
or
The heart needs more than usual
Why too little?
• Intraoperative Blood Loss
• Post-operative blood loss
– Coagulopathies
– HIT (heparin induced
thrombocytopenia)
– Monitor CTT drainage and Replace
• Third Spacing
Why might they need more
preload than usual?
• Stiff Right Ventricle
• Right Ventricular Hypertrophy
– Tetrology of Fallot
– Unbalanced AV-Canal
• Myocardial edema
– Prolonged pump run, long cross
clamp
– Generalized edema (anasarca)
Why else?
• Atrial arrhythmias or Junctional
rhythms
– No atrial ‘kick’
• Passive blood flow to the lungs
Preload - treatment
Crystalloids
vs.
Colloids
Crystalloids
• Isotonic Fluid
• Normal Saline
– 154 mEq NaCl/l
• Lactated Ringers
–
–
–
–
–
130mEq Na+
4mEq K+
3mEq Ca+2
109mEq Cl28mEq Lactate
Colloids
• Oncotic properties
• More likely to stay intravascular
• Longer duration of action
• Less likely to contribute to edema
• Some are actually quite useful
Commonly used colloids
• 5% Albumin
• 25% Albumin
• Plasma - FFP
• Packed Red Blood Cells (PRBC’s)
• Platelets
• Cryoprecipitate
• Hespan/ Haes-Steril
Back to our diagram
Contractility
• Often impaired
• Secondary to surgery
• Increased workload
• Somewhat dependent on preload
Adrenergic Agonists
• Dopamine
• Dobutamine
• Epinephrine
• Phenylephrine
• Milrinone
Dopamine
• Alpha, beta and dopaminergic agonist
• Dose range: 2-20mcg/kg/min
• Effects: Low dose 2-5mcg/kg/min
– ‘renal’ dose
– Middle range: more beta
– Higher range: alpha starts to predominate
• Use: inotrope, vasoconstriction, ‘renal’
effects
• Risk: ischemia, vasoconstriction,
tachycardia
Dobutamine
• b1 selective
• Dose range: 3-20mcg/kg/min
• Effect: increased inotropy and
chronotropy
• Use: to increase contractility,
strength of contraction
• Risk: vasodilation in higher dose
range, tachycardia
Epinephrine
•
•
•
•
•
Trade name Adrenalin
Ad/Renal/in = Above the kidney
Epi/Nephr/in = Above the kidney
works at all receptors b>a
Dose range: 0.01mcg/kg/min 2mcg/kg/min
• Use: most potent inotropic effect
• Risk: vasoconstriction, ischemia,
acidosis, tachycardia
Milrinone
• A phosphodiesterase inhibitor
• Inhibits breakdown of cAMP
Remember that diagram?
Afterload
• Refers to work against which the heart
is contracting
• Either an immediate obstruction such as
valvular stenosis or hypertrophy
• Or related to systemic vascular
resistance
• As you might imagine decreasing the
afterload will help the heart to contract
Afterload Reduction
•
•
•
•
3 drugs we use
Nitroprusside
Nitroglycerin
Nitric Oxide
Nitric Oxide
• FDA approved for treatment of
Persistent Pulmonary Hypertension of
the Newborn (PPHN)
• Has been used to treat post operative
pulmonary hypertension in congenital
heart disease
• Literature supporting its use outside of
PPHN is sparse and/or weak
• Very expensive therapy - $3000/day
Nitroprusside
• Mechanism of action: NO donor
• Site of action: primarily on arteries
• Action: vasodilator
• Dose range: 0.3-7.0mcg/kg/min
• Risks: profound hypotension,
cyanide toxicity,
methemoglobinemia
Nitroglycerin
• Mechanism of action: NO donor
• Site of action: veins and arteries, plus
coronary arteries
• Action: vaso and venodilator
• Dose range: 0.3-5.0mcg/kg/min
• Use: post-op Transposition, or other surgery
involving coronary arteries
• Risks: can decrease preload, profound
hypotension, methemoglobinemia, cyanide
toxicity
Who needs afterload reduction?
• Decreases force against which
heart has to contract
• Particularly needed for patients
with aortic insufficiency or mitral
regurgitation
– Can help to decrease the amount of
regurgitation
• Poor LV function
Pulmonary Support
• Two main goals:
• Oxygenation
• Ventilation
Ventilation
• General Goals: normal ventilation and
minimum time on the ventilator
• Passive Pulmonary Blood Flow
– Glen Shunt
– Fontan Procedure
• With passive blood flow, possibly more
effect from airway pressures, want to
minimize
– Lower Pmax, lower Inspiratory time,
minimal peep
Pulmonary Hypertension
• Seen in a variety of patients
– Most commonly those with lesions
that had big left to right shunts
(increased pulmonary blood flow)
– Used to increased levels of blood flow
– ‘reactive’ pulmonary bed
• Atrioventricular Canal
• Tetrology of Fallot
Treatment for Pulmonary HTN
• Classic:
• Hyperventilation
– pH 7.50-7.55
– Similar to treatment of PPHN in the
neonate
• Oxygen
– A potent pulmonary vasodilator, keep
oxygen high
Oxygenation
• What should be the IDEAL oxygen level
after the surgery?
– If complete correction with no shunt then
Pa02 of 500 mmHg
• Is there a residual shunt?
• Is there a pulmonary reason for the low
Pa02
• Monitor using ABG and pulse oximeter
Oxygenation
• Pulse Oximeter
– Just a Monitor!!!
– Will never replace
ABG!!!
• 40 mmHg = 70%
• 50 mmHg = 80%
• 60 mmHg = 90%
Renal
• Diuresis is good but not too much
• ATN common post-operative
• 3 classes
– Loop
– Thiazide
– Osmotic
• Electrolyte Imbalance: HypoKalemia,
HypoNatremia, HyperNatremia,
HypoCalcemia, HypoMagnesemia,
HypoPhosphatemia
Renal
• Monitor Input and Output hourly
• Watch Vital Signs
– BP, HR
– Pulse Oximeter
– Perfusion
• Daily Weight
Pain Assessment
• Patient Underwent Surgery!!!
• Monitor BP, HR, RR, Facial
Expression, Body Position
• Scoring Systems
– Oucher Analog Scale
• Patient may express discomfort
Pain Control
• Opiate analgesics
– Morphine sulfate
• NonSteroidal Analgesics
– Ketorolac
• Should know the duration of action
and side effects
Nutrition
• Dextrose/ glucose infusion is
important
• Phosphorous needs for ATP
formation and rhythm
maintainance
• Electrolytes (Na, K, Ca, Mg)
• Enteral vs. parenteral feeding
• For Body repair and growth
References
• Text
– Rogers: Textbook of Pediatric
Intensive Care
– Critical Cardiac Disease of Infants and
Children
• On-line
– Picubook.net
– Pedi-heart web-site
Thank You For Your Kind
Attention
Have a Nice Day!!!