Transcript Postoperative Care in the Patient With Congenital Heart

UTHSCSA Pediatric Resident Curriculum for the PICU
Postoperative Care in the
Patient With Congenital
Heart Disease
General Principles
 Patient homeostasis
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Early – declining trends do not correct
themselves
Late – time can be important diagnostic tool
“The enemy of good is better”
Specific Approaches
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Cardiovascular principles
Approach to respiratory management
Pain control/sedation
Metabolic/electrolytes
Infection
Effects of surgical interventions on these
parameters
NO PARAMETER EXISTS IN ISOLATION
Cardiovascular Principles
 Maximize O2 delivery/ O2consumption ratio

Oxygen delivery:
Cardiac Output
 Ventilation/Oxygenation
 Hemoglobin
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Maximizing Oxygen Delivery
Metabolic acidosis is
the hallmark of poor
oxygen delivery
Maximizing Oxygen Delivery
OXYGEN
DELIVERY =
OXYGEN
CONTENT
X
CARDIAC
OUTPUT
Maximizing Oxygen Delivery
Cardiac Output
O2 Content =
Saturation(O2 Capacity)+(PaO2)0.003
 Oxygen Capacity = Hgb (10) (1.34)
 So . .
 Hemoglobin and saturations are determinants
of O2 delivery
Hemoglobin (gm/dl)
Maximizing Oxygen Delivery
Cardiac Output
Gidding SS et al 1988
y=-0.26(x)+38
R=0.77
S.E.E.=1.6
23
21
19
17
15
13
65
70
75
80
Saturation(%)
85
90
Maximizing Oxygen Delivery
Cardiac Output
Cardiac
Output
=
Stroke Volume
 Contractility
 Diastolic Filling
 Afterload
Stroke
Volume
X
Heart
Rate
Heart rate
 Physiologic Response
 Non-physiologic
Response
 Sinus vs. junctional vs.
paced ventricular rhythm
Maximizing Oxygen
 Oxygen consumption
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Decreasing metabolic demands
Sedation/ paralysis
 Thermoregulation
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Ventilator Strategies
 Respiratory acidosis/hypercarbia
 Oxygenation
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Physiology of single ventricle/shunt lesions
Oxygen delivery!
 Atelectasis – 15-20 cc/kg tidal volumes.
 PEEP, inspiratory times
Ventilator Strategies:
Pulmonary Hypertension
 Sedation/neuromuscular blockade
 High FiO2 – no less than 60% FiO2
 Mild respiratory alkalosis
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pH 7.50-7.60
pCO2 – 30-35 mm Hg
 Nitric Oxide
Ventilator Strategies:
Pulmonary Hypertension
Precipitating
Event
-Cold stress
-Suctioning
-Acidosis
Metabolic Acidosis
Hypercapnia
Hypoxemia
Low output
Ischemia
Increased
PVR
Decreased Pulmonary Blood Flow
Decreased LV preload
RV dysfunction
Central Venous Hypertension
Pain Control/Sedation
 Stress response attenuation
 Limited myocardial reserve – decreasing
metabolic demands
 Labile pulmonary hypertension
 Analgesia/anxiolysis
Pain Control/Sedation
Opioids
 MSO4 – Gold standard: better sedative effects
than synthetic opioids
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Cardioactive – histamine release and limits
endogenous catecholamines
 Fentanyl/sufentanyl
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Less histamine release
More lipid soluble – better CNS penetration
Pain Control/Sedation
Sedatives
 Chloral hydrate
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Can be myocardial depressant
Metabolites include trichloroethanol and
trichloroacetic acid
 Benzodiazepines
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Valium/Versed/Ativan
Pain Control/Sedation
Muscle relaxants
 Depolarizing – Succinylcholine
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Bradycardia ( ACH)
 Non-depolarizing
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Pancuronium – tachycardia
Vecuronium – shorter duration
Atracurium
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“spontaneously” metabolized
Histamine release
Pain Control/Sedation
Others:
 Barbiturates – vasodilation, cardiac depression
 Propofol – myocardial depression, metabolic
acidosis
 Ketamine – increases SVR
 Etomidate – No cardiovascular effects
Fluid and Electrolytes
 Effects of underlying cardiac disease
 Effects of treatment of that disease
Cardiopulmonary Bypass
 “Controlled shock”
 Loss of pulsatile blood flow
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Capillary leak
Vasoconstriction
Renovascular effects
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Renin/angiotensin
 Cytokine release
 Endothelial damage and “sheer injury”
Cardiopulmonary Bypass
Stress
Response
SIRS
Lung Fluid
Filtration =  [(
Renal
Insufficiency
Microembolic
Events
Microvascular
)Hydrostatic Pressure
(
Fluid
Administration
Microvascular
)]
Oncotic Pressure
Hemorrhage
Capillary Leak Syndrome
Feltes, 1998
Circulatory Arrest
 Hypothermic protection of brain and other
tissues
 Access to surgical repair not accessible by CPB
alone
 Further activation of SIRS/ worsened capillary
leak.
Fluid and Electrolyte
Principles
 Crystalloid
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Total body fluid overload
Maintenance fluid = 1500-1700 cc/m2/day
 Fluid advancement:
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POD 0 : 50-75% of maintenance
POD 1 : 75% of maintenance
Increase by 10% each day thereafter
Fluid and Electrolyte
Principles
Flushes and Cardiotonic Drips
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Remember: Flushes and Antibiotics = Volume
UTHSCSA protocol to minimize crystalloid: Standard Drip Concentration
Mix in dextrose or saline containing fluid to optimize serum glucose & electrolytes
Sedation: (Used currently as carrier for drips)
MSO4
2cc/hr = 0.1 mg/kg/hr
Fentanyl
2 cc/hr = 3 mcg(micrograms)/kg/hr
Cardiotonic medications:
Dopamine/Dobutamine
50 mg/50 cc
Epi/Norepinephrine
0.5 mg/50 cc
Milrinone
5 mg/50 cc
Nipride (Nitroprusside)
0.5 mg/50 cc
Nitroglycerin
50 mg/50 cc
PGEI
500 mcg/50 cc
Fluid and Electrolyte
Principles
 Intravascular volume expansion/ Fluid challenges
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Colloid – osmotically active
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FFP
5% albumin/25% albumin
PRBC’s
HCT adequate: 5% albumin (HR, LAP, CVP)
HCT inadequate: 5-10 cc/kg PRBC
Coagulopathic: FFP/ Cryoprecipitate
Ongoing losses: CT and Peritoneal frequently = 5%
albumin
Metabolic Effects
 Glucose
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Neonates vs. children/adults
Hyperglycemia in the early post-op period
Metabolic Effects
 Calcium
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Myocardial requirements
Rhythm
 Contractility
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Vascular resistance
NEVER UNDERESTIMATE THE POWER OF
CALCIUM!
Calcium/inotropes
Alpha 1
DAG
Phosphodiesterase
Adenylate
Cyclase
Beta 1
Regulatory
G Protein
Na
Ca
IP3
Sarcoplasmic
Reticulum
cAMP-Dependent PK
K
Na
SR
Ca
Ca
Ca
Ca
Metabolic Effects
 Potassium
Metabolic acidosis
 Rhythm disturbances
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Thermal Regulation
As a sign to watch, and an item to
manipulate…
 Perfusion
 Junctional ectopic tachycardia
 Metabolic demands
 Oxygen consumption
 Infection
Infection
 Routine anti-staphylococcal treatment
Effects of Surgical
Interventions
 Cardiopulmonary Bypass vs. Non-Bypass
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Fluids and electrolytes
 Modified ultrafiltration
 Types of anatomic defects
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Overcirculated – increased blood volumes
preoperatively
Undercirculated – reperfusion of area previously
experiencing much reduced flow volumes.
Summary
 Optimize oxygen delivery by manipulation of cardiac
output and hemoglobin
 Sedation and pain control can aid in the recovery
 Appreciate effects of cardiopulmonary bypass and
circulatory arrest on fluid and electrolyte management
 Tight control of all parameters within the first 12 hours;
after that time, patients may be better able to declare
trends that can guide your interventions.