Peds summary part 2 Flashcards
____ can be used to try and close a PDA
Indomethacin (an anti-prostaglandin)
The ductus arteriosus remains patient in utero due to
hypoxia, mild acidosis, & placental prostaglandins**
Left to right shunts
connects arterial and venous circulation resulting in increased pulmonary blood flow “pink lesions”***
ex. PDA, ASD, VSD
Right to left shunts
venous blood is ejected systemically; there is decreased pulmonary blood flow & patients are cyanotic “blue lesions”
- ex. ASD or VSD with pulmonary HTN, TOF during Tet spell
Eisenemenger’s syndrome:
when large VSDs are uncorrected the resulting pHTN can reverse the shunting of blood across the defect
the previous left to right shunt becomes right to left
- the shunt reverses direction when the PVR is high enough
The Qp/Qs is the
ratio of pulmonary to systemic blood flow
we use it to determine over circulation to the pulmonary system or LV workload
normal is equal to 1:1
tells us the degree of shunting
Coarctation
a narrowing in the aorta commonly occurring immediately distal to the origin of the left subclavian artery
critical coarctations will present with circulatory collapse, shock, & acidosis due to poor distal perfusion
- prostaglandin is started to reopen the ductus & distal perfusion remains ductal dependent until surgery
-presents with upper extremity hypertension, decreased lower extremity pulses & LVH
-surgical approach is left thoracotomy and subclavian flap angioplasty sacrifices the left subclavian artery & the left arm will then need to be perfused by collateralization
-blood pressure must be measured in the right arm
The Ross procedure
- performed on patients diagnosed with aortic stenosis & is an alternative to prosthetic valve replacement
- diseased aortic root is resected the patient’s own pulmonary valve root is excised & implanted into the aortic position
- coronary arteries are then re-implanted into the “neo-aortic” root
- An RV to PA connection and valve is made with cadaveric tissue or a conduit
- advantages: freedom from long-term anticoagulation, the valve grows as the patient grows
- disadvantages- single valve disease (aortic) is treated with 2 valve procedure
Blalock-Taussing-Thomas shunt
-operation to create a type of systemic to pulmonary shunt
Classic BTS- subclavian artery is divided and directly anastomosed to the ipsilateral pulmonary artery
- cannot take BP in left arm/ pulseless or weak pulse; grows with the individual
Modified BTS- synthetic shunt between the subclavian artery & PA
- ipsilateral arm reflects true pressures & available for a-line placement
-artificial material will not grow with the patient
-hypotension leads to sluggish flow & possibly thrombosis which can be critical**
Tetralogy of fallot
four key features: VSD, Right ventricular outflow obstruction, overriding aorta, right ventricular hypertrophy
limitation of pulmonary blood flow & the magnitude of ventricular level right to left shunting account for the degree of cyanosis
-TET spells are acute dynamic increases in the pulmonary outflow tract obstruction may result in an intensely cyanotic epidosde due to right to left shunting
Anesthetic treatment: 100% fiO2, sedation, fluid, beta blocker, alpha agonist to increase afterload & slow down the heart rate
Anesthesia for TOF reapir:
avoid “tet spell”
generous premedication
sufficient anesthesia & analgesia
avoid reductions in SVR
RV output is the limiting factor on overall CO
treat a tet spell quickly with phenylephrine
Treating a “Tet spell” intraoperatively includes:
exacerbated right to left shunting (cyanosis) 100% oxygen knees to chest fluid bolus hyperventilation sedation esmolol phenylephrine 1-10 mcg/kg IV
Postconceptual age=
gestational age + postnatal age
Marfan syndrome:
multisystem disorder resulting from a mutation in connective tissue protein
aortic or pulmonary artery dilation, mitral valve prolapse**
Anesthetic considerations: avoid hypertension b/c of risk for aortic dissection, increased risk for pneumothorax use careful PPV, careful positioning due to joint laxity, may require larger than normal doses of spinal or epidural medications due to increased length and increased CSF
Noonan syndrome:
autosomal dominant
anesthetic considerations: possible difficult intubation, difficult PIV placement with edema, chest deformities may lead to decreased lung function, bleeding diathesis may increase the amount of periop bleeding, renal impairment may affect metabolism of renally excreted drugs
spinal abnormalities may make epidural catheter placement diffuclt
SBE prophylaxis, & HOCM considerations
Williams syndrome
occurs due to a deletion on chromosome 7
risk of sudden death due to severe myocardial ischemia from coronary artery stenosis*****
Anesthetic considerations
risk of sudden death outside of the hospital as well as during cardiac catheterization & during anesthesia
baseline EKG & ECHO
preparation for possible ECMO
SBE prophylaxis
DiGeorge syndrome:
22q11 micro deletion involved in development of thymus
M&M associated with cardiac defects, T-cell immunodeficiency, & seizures related to hypocalcemia
micrognathia
hypocalcemia tetany or seizures
thymus transplant is treatment for immune disorder
Anesthetic considerations: micrognathia may make for difficult intubation, short trachea, choanal atresia precludes nasal trumpets, all blood products must be irradiated, careful asepsis, calcium levels must be evaluated
Down synrome:
trisomy 21 1/2 have CHD atlantoaxial cervical instability assess for OSA prone to bradycardia on induction challenging vascular access downsize ETT due to subglottic stenosis hypothyroidism postoperative stridor respiratory complications common
Known factors to increase pulmonary vascular tone
hypoxemia & use of <30% fiO2 hypercarbia/acidosis hypothermia atelectasis transmitted positive pressure & PEEP stress response/stimulation/light anesthesia
Known factors to decrease pulmonary vascular resistance
increasing inspired oxygen to 100%
hyperventilation
potent inhalation agents reduce SVR more than PVR
nitric oxide
Chronic Fontan complications:
dysrhythmias, thrombosis, protein losing enteropathy
Anesthetic considerations for palliative procedures for HLHS:
prior to stage 1, the PDA must be kept patent with PGE1 to allow for systemic perfusion
restrict excessive pulmonary blood flow (allow mild hypercarbia, allow low oxygen concentrations, use of PEEP)
higher than expected O2 saturations may imply inadequate systemic perfusion & pulmonary overload
patients may require inotropic support
minimize myocardial depression
prevention & treatment of pulmonary hypertensive crisis
Hypoplastic left heart syndrome is
used to describe a spectrum of defects with the common denominator being under development of the heart’s left side- aorta, aortic valve, LV & MV
results in single ventricle physiology & complete mixing of systemic & pulmonary circulation with expected oxygen saturated 75-80%
at birth, PGE1 is started to maintain ductal patency because these babies are ductal dependent**
Surgical palliation for HLHS includes:
Stage 1 Norwood* soon after birth
Stage 2 Bidirectional Glenn 4-12 months
Stage 3 Fontan 1.5-3 years
Describe Norwood with Shunt
connection between systemic to pulmonary circulation
anticipate arterial oxygen saturation 75-80%*****
RV ejects into the systemic circulation
Describe Bidirectional Glenn
direct anastomosis between the SVC and a pulmonary artery branch
requires low PVR & blood flow is passive*****
expected arterial oxygen saturation is 75-85%
Describe Fontan procedure
the inferior vena cava is connected to the pulmonary vasculature
completes the separation of the pulmonary & systemic circulations
expected arterial oxygenation saturation of 88-93%
