TEST 2 Flashcards
During fetal circulation: PVR is _____________ (the lungs are bypassed) and SVR is ___________
PVR is HIGH
SVR is low
During fetal circulation _____ is high and _____ is low causing a _______ to _______ shunt
PVR
SVR
R to L shunt
During fetal circulation; Foramen ovale; blood shunts from ___ to _____?
RA to LA
Connection between PA and Aorta?
Ductus Arteriosus
- Characteristics of Hypoplastic Left Heart Syndrome?
- Very small LV
- Mitral and aortic valve stenosis/atresia
- Hypoplastic aortic arch
- Pulmonary blood flow (BF) from LA via ASD to RA/RV
- Single ventricle (RV)
- Systemic BF from RV to PA to aorta via PDA
Hypoplastic Left Heart Syndrome (HLHS) have patent ________ and _______ and have _______ LV
Patent ductus Arteriosus
Patent foramen ovale
Hypoplastic left ventricle
If mitral valve is completely stenosed what is it called?
Atresia
What kind of defect do you need with HLHS?
ASD; have to have atrial septal defect because road block in the LA.
How often is HLHS diagnosed?
2/10,000 live births
When is HLHS usually diagnosed?
At birth usually diagnosed prenatal
What do HLHS patient present with? (4 S\S)
Tachypnea
Tachycardia
Systolic murmur
Cyanosis
What side of the heart is underdeveloped in HLHS?
The L side of the heart is underdeveloped
What are the 3 procedures that can convert the HLHS into a single- ventricle type circulation? And when are they performed?
- Norwood: neo- aorta and BT shunt (within days after birth)
- Bidirectional Gleen: passive pulmonary BF from SVC (within 6 mo of age)
- Fontan: passive pulmonary BF from SVC and IVC (within 1.5-3 years of age)
Norwood stage operation is the creation of _______ and placement of ____ shunt for passive/active pulmonary blood flow.
Neo- aorta
BT
Passive
Norwood is the reconstruction of ________ in neonatal period
Neo- aorta
What arteries are disconnected from the pulmonary trunk in the HLHS- Norwood?
The pulmonary arteries are disconnected from the pulmonary trunk
In the Norwood HLHS the only blood supply to the lungs is provided from either a shunt from __________ artery (Blalock- Taussig shunt) or from the R/L ventricle (Sano modification)
Are these shunts considered passive or active and what are they dependent on?
Subclavian artery
Right ventricle
Passive blood from what and dependent on pressures
After the HLHS Norwood are patients still cyanotic?
Yes SpO2 70’s- 80’s
What is the general anesthetic technique for Norwood anesthesia considerations?
High dose opioid techniques
Where is venous access typically for the Norwood anesthesia?
Venous access often via femoral vein; avoid internal Jugular vein for future Glenn Shunt
What is common after Norwood procedure?
Post op myocardial dysfunction
After Norwood procedure it is hard to balance SVR and PVR after CPB usually require 3 medications?
Milrinone
Epinephrine
Dopamine
How long does the sternum stay open after a Norwood procedure?
Several days post op
When does the Glenn operation take place?
6 months of age
What happens during the Glenn operation?
The BT shunt is taken down and a new connection is created from the SVC to the PA
What is a result of the Glenn shunt?
Pulmonary blood supply that is provided by systemic venous blood from the SVC.
After the Glenn shunt is flow passive or active and what does it depend on?
Flow is passive and depends on pulmonary arterial pressures
The infant remains cyanotic after the Glenn shunt with arterial saturations in the mid _______ because desaturated/saturated blood from the IVC continues to flow into the heart and ______ circulation
80’s
Desaturated
Systemic
What does the Fontan surgery involve?
Connecting the IVC to the PA via extracardiac or intracardiac conduit to create a single ventricle circulation (Fontan)
After the Fontan where does the RV pump blood?
The single RV pumps blood to the systemic circulation
After the Fontan procedure where and how is the pulmonary blood supplied?
Provided by passive flow from SVC and IVC
In the Fontan procedure it is common for a small hole to be created between the _________ conduit and the ______ so that if PVR/SVR rises, blood will be directed to the RA/LA and allow cardiac output to be maintained.
Extracardiac
RA
PVR
RA
What does the fenestration between the extracardiac conduit and the RA prevent?
A state of low CO
Even after the Fontan procedure what do these kids need for long term?
Heart transplant because the RV (the only ventricle that fails) over time
Post op Fontan what must remain very balanced?
PVR must remain very balance post operatively
Post op Fontan, in order to maintain PVR, we must minimized?
To minimize atelectasis
What is occasionally required after Fontan procedure to maintain PVR?
Nitric oxide
If an inotropy is required what is a good choice d/t its beneficial effects on PVR post op fontan?
Milrinone
What is beneficial in terms of hemodynamic post op fontan?
Early extubation
What are 2 anesthetic considerations with HLHS?
- Essential to maintain the balance of PVR and SVR
2. Oxygen is a drug and should be used cautiously in congenital heart disease patients
3 ways FiO2 influences PVR?
- Hypoxia causes pulmonary vasoconstriction but causes systemic vasodilation
- Hypoxia and acidosis are potent stimuli for increase in PVR
- Reversely, high FiO2 will cause a significant decrease in PVR and potentially increased blood flow toward the lungs and away from systemic circulation
In some HLHS children (who present for a Norwood procedure) excessive blood flow to the lungs resulting from a significantly high/low PVR and a relatively high/low SVR steals blood from systemic circulation, leading to hypotension/hypertension, myocardial ischemia and progressive acidosis.
Low PVR
High SVR
Hypotension
Why is it dangerous to administer high FiO2 to an HLHS patient?
Because it can decrease PVR
If the PVR is greater than SVR what happens to the patient?
The child develops progressive desaturation
It can be difficult to manipulate SVR and PVR predictably -> PVR is well understood and vasoactive drugs work on both circulations. T/F?
False PVR is not well understood
Potent volatiles reduce ______ more than _______.
SVR
PVR
PVR is decreased in in children by increasing/decreasing FiO2 (100%) and during hyperventilation
Increasing
Low ETCO2 causes a increase of PVR. T/F
False; causes a decrease
PVR is increased with what 4 things?
- PEEP
- Acidosis
- Hypothermia
- Low FiO2 (30% or less)
Phenylephrine increases SVR/PVR more than SVR/PVR?
What shunt will it reduce and what shunt will it increase?
Increases SVR more than PVR
Reduces R->L shunt
Increases L-> R shunt
7 factors that increase PVR?
- Hypoxemia
- Hypercapnia (increase ETCO2 causes increase in PVR)
- Academia
- Hypothermia
- Atelectasis
- Transmitted positive airway pressure
- Stress response/ stimulation/ light anesthesia
2 anesthesia considerations with HLHS?
- Keep neonate spontaneously breathing with FiO2 of 21 % and prostaglandin E1 infusion to maintain ducal patent (to keep PDA open)
- Keep normal/high PaCO2
What are prostaglandins?
Naturally occurring hormone- like substance (it circulates in the fetus’ bloodstream and keeps the ductus Arteriosus DA open)
What happens to prostaglandins after birth?
They decrease plus increased oxygen tension will close the ductus Arteriosus
What can you give to maintain patent PDA?
Prostaglandins
What can you give if PDA is undesired?
Give Indomethacin or PDA ligation
What prostaglandin maintains patency of ductus Arteriosus?
E1
When does prostaglandin E1 maintain patency of ductus arteriosus?
When the body is supplied by R -> L ducts flow such as:
Cases of interrupted aortic arch
Critical aortic stenosis
HLHS
The PDA can supply pulmonary blood flow from the aorta to the lungs in lesions such as what? (3 things)
- Pulmonary atresia
- Tricuspid atresia
- Severe tetrology of Fallot
Subacute bacterial endocarditis antibiotic prophylaxis is suggested for children that are?
High risk
Subacute bacterial endocarditis prophylaxis: Amoxicillin PO
50 mg/kg
Subacute bacterial endocarditis ampicillin IM/IV dose?
50 mg/kg
Subacute bacterial endocarditis cefazolin IM/IV dose?
50 mg/kg
Subacute bacterial endocarditis for ceftriaxone IM/IV dose?
50 mg/kg
What is an appropriate abx if pt is allergic to PCN/Ampicillin?
Clindamycin IV 20 mg/kg
When are air bubbles very dangerous in children?
In children with R -> L shunts
Air bubbles are very dangerous in children with R -> L shunts because it is shunted directly into ___________ circulation.
Systemic
Patients with L-> R shunts can transiently reverse their shunts during _______ or __________ when the normal trasarterial pressure gradient is reversed.
Coughing
Valsalva
What is the induction agent of choice in pediatric anesthesia?
SEVO
At what MAC can Sevo SLO’s the HR and cause respiratory depression?
> 1.5 MAC
What is the “Hole” in the atrial septum =connecting with RA with LA -> because PVR is HIGH, blood shunts from _______to ________ (bypassing the lungs)
Foramen ovale
Right to Left
What is the connection between Pulmonary artery and aorta = blood flows from RA -> tricuspid valve into the RV - PA -> bypasses the lungs again to take a shortcut to the ________________ (systemic circulation)?
Ductus arteriosus
Aorta
After birth, the neonate takes its first breaths, the lungs inflate and PVR _______ while the placenta is disconnected and blood is not drained back to mom ___________ SVR.
Reduces PVR
Increasing SVR
With decreasing PVR, increasing SVR, blood flow becomes EASIER/DIFFICULT into the _________ and becomes oxygenated.
EASIER
Lungs
The increased pressure in the LA (compared with RA) pushes the flap of the _______ _________ shut.
Foramen ovale
The increased pressure in the aorta allows some “back flow” of blood via __________ __________ back into the pulmonary artery (PA) which causes additional _______ of the blood.
Ductus arteriosus
Oxygenation
After birth: eventually the __________ changes within the two circulation and reduced levels of __________ causes the closure of ductus arteriosus and foramen ovale within days after birth.
Pressure changes
Prostaglandins
Prostaglandins are naturally produced by the _____ and available for the fetus during _____. Some congenital heart disease where it is absolutely imperative to keep the DA open. Having _______ keeps the DA and FO patent.
Mother
Pregnancy
Prostaglandin
What is a “hole” within the atrial septum between RA and LA?
Atrial Septal Defect (ASD)
What is the “hole” within the ventricular septum = between RV-LV?
VSD = ventricular septal defect
What kind of shunt is due to higher pressure in the left heart, blood flows back to the right hear via ASD/VSD, causing increased blood flow in the lungs = pulmonary congestion which can lead to ________?
Left to right shunt
Pulmonary HTN
What kind of shunt is occurring when the blood bypasses the lungs because of obstruction to the lungs (ie pulmonary stenosis) -> blood flows through ASD/VSD or both systemic side =________?
Right to Left shunt
Cyanosis
What occurs in “simple” left to right shunt? And List the 4 congenital heart disease
Increased pulmonary blood flow
ASD (Atrial Septal Defect)
VSD (Ventricular Septal Defect)
AVSD (Atrioventricular Septal Defect)
AP window (aortapulmonary window)
What occurs in “simple” right to left shunt? List the 4 congenital heart disease.
Decreased pulmonary blood flow -> CYANOSIS
TOF (Tetrology of Fallot)
Pulmonary atresia
Tricuspid atresia
Ebstein anomaly (congenital malformation of tricuspid valve)
What occurs in complex shunts? List the 4 Congenital Heart Disease.
Mixing of pulmonary and systemic blood flow with CYANOSIS
TGA (Transposition of great arteries)
Truncus arteriosus
DORV (Double outlet RV)
HLHS (Hypoplastic Left heart Syndrome)
List 4 obstructive lesions.
Pulmonary stenosis
Aortic Stenosis
Mitral stenosis
Coarctation of Aorta
__________ ASD is causing a left to right shift through the defect.
Secundum
What defect is common heart defect in children (10% of CHD)?
Secundum ASD
What type of ASD is small and usually and less commonly requiring intervention if isolated? Sometimes the defect is part of AV canal defects and is associated with a split (cleft) in one of the leaflets of the mitral Valve.
Primum ASD
What is the more common ASD when part of the atrial septum fails to close completely while the heart is developing, causing an opening to develop in the center of the wall and separating the two atria?
Secundum ASD
Ventricular septal defect shows a _______ to _______ shunt. Most common congenital defect in children (20% of CHD in children).
Left to Right
Complete atrioventricular septal defect (AVSD) is showing a ________ to ______ shunt through both ____ and ____ components of the defect and also a single common ______ valve.
Left to Right shunt
Atrial and ventricular
Atrioventricular valve
Patent ductus arteriosus (PDA) shows a _______ to _____ shunt. The blood flows from _____ to _____.
Left to Right shunt
Aorta to PA
PDA extends from the descent aorta to the main _____ and usually closes soon after _____.
PA
After birth
PDA is common in pre-term infants- requiring often ____ ____.
Mechanical ventilation
Before birth: in PDA- high PVR directs blood flow toward ___.
Aorta
After birth with PDA: PVR ____ and SVR ____ causes a ____ to ____ shunt (retrograde flow from aorta back to PA)
PVR decrease
SVR increase
Left to Right
PDA ligation: closure via thoracotomy, often done in NICU with __________ <1000 gm.
Extremely-low birth weight
What are some perioperative risks with PDA-Ligation? (5)
Difficult ventilation/desaturation because of lung retraction
Tearing of PDA with massive hemorrhage
Inadvertent ligation of aorta or pulmonary (PA)
Endocarditis
Paradoxical air embolism
When doing PDA-ligation and monitoring in NICU, what monitoring is required?
Standard monitoring (A-line preferred)
ETCO2
Two pulse Oximeter
Where do you place your two pulse Oximeter while monitoring in the NICU while performing PDA-ligation?
Preductal - RIGHT hand
Postductal - lower limb
If the pulse is lost from the lower lim during a test clamping of the duct during PDA Ligation, this might indicate _____.
That the aorta has been clamped inadvertently
What (5) things are occurring in Tetrology of Fallot (TOF)?
Pulmonary stenosis
VSD
Overriding aorta
RV hypertrophy
Right to left shunt = cyanosis
TOF is the most common _____ _____ and accounts for ____ to ___ % of CHD.
Cyanosis CHD
6-11%
What are the (4) things occurring the heart during Tetrology of Fallot (TOF)?
RV-Outlet Tract obstruction/stenosis (infundibular obstruction/spasm) —>there is a partial obstruction (stenosis) of the RV outflow to the lungs and pulmonary valve
VSD
Increased outflow in aorta. Overriding aorta =aorta is displaced to the right so that it appears to arise from both ventricles and straddles the VSD
RV hypertrophy
In TOF,_____ = hypercyanotic spells occur when there is an increase in RIGHT to LEFT shunting
“Tets Spells”
In TOF, The degree of hypoxemia depends on the relationship between ____ and ___ that determines the degree of RIGHT to LEFT shunting
RVOTO (RV-outlet tract obstruction) and SVR
The cause of “tets spells” (TOF-hypercyanotic spells) is UNCLEAR, but they occur during what (6) things?
Crying
Feeding
During anesthesia/surgical stimulation
Metabolic acidosis
Increased PaCO2
Circulating catecholamines
How do you treat TOF-Hypercyanotic “spells”?(6)
100% oxygen
HYPERventilation (decreased ETCO2 will decrease PVR)
Increase preload (IVF)-give fluid deficit early or give bolus of 10 ml/kg of crystalloid
Sedation
Vasoconstriction with Phenylephrine (Increases SVR to reverse R-L shunt)
B-blocker to relax infundibular spasm and reduce HR
TOF repair: surgical trend goes toward earl, complete repair which involves closure of _____ and relief of _______.
Closure of VSD
Relief of RVOTO (RV outlet tract obstruction
What is a modified repair of TOF to improve systemic to pulmonary shunt (from subclavian artery to PA) and to improve pulmonary blood flow?
Modified Blalock-Taussig (BT) shunt
What are (4) Anesthesia consideration for a TOF repair?
Presedate to prevent crying on induction, increase risk of “tets spells” during induction/surgery
Place A-line on arm opposite to the side of subclavian anastomosis, because subclavian artery is going to be clamped
Snug ETT with little air leak - lung retraction makes ventilation difficult
Prepare for blood transfusion - potential bleeding after clamp release
Post op pulmonary blood supply is predominantly dependent on size of BT shunt. True or False.
True
If BT shunt is too small, it can lead to ?
Low saturation
If BT shunt is too large, what can occur?
Infant may develop HF/pulmonary edema
During a TOF repair with a BT shunt, what monitor can be used intra op to assess RV function?
TEE
TOF repair: pulmonary blood flow is dependent on SBP. The greater the BP, the more blood flow towards the lungs which leads to LOWER saturation. True or False.
False
HIGHER
In Transposition of Great Vessels (TGA), the ____ arises from the RV and the _____ arises from the LV. The coronary arteries are shown arising from the ____. These children are _____.
Aorta arises from RV
Pulmonary artery arises from LV
Coronary artery arises from Aorta
CYANOSED
What are the 2 types of TGA?
Pure TGA
TGA with VSD
In Pure Transposition of the Great Arteries, two circulation run ________ rather in series. What is this called?
Parallel
Parallel circulation
Some mixing occurs through the PDA or VSD (present in 25%) of Transposition of the Great Arteries (TGA). True or false.
True
Ductal patency is maintained after birth with (2)
Prostaglandins E1 infusion
Balloon atrial septostomy is performed urgently in neonatal period
During the _______, the aorta (Ao), the pulmonary arteries and coronary arteries are disconnected from the origins.
Arterial Switch
In “Arterial Switch,” The PA is move ____ to the aorta. Aorta is connected to the ____. Pulmonary artery is connected to the ____.
ANTERIOR
LV
RV
Coronary arteries are connected to the ____ = most crucial part of successful outcome of arterial switch operation
New-aortic root
“Arterial Switch” Operation often required early at age _____. If untreated, pt will die within ____ due to ___ and ____.
2-3 weeks
1 year
Hypoxia and heart failure
TGA: if the patient has an arterial switch and fully repair, children still have problems later in life. True or False.
False. If fully repaired, children can expect normal life.
After an “arterial switch” what are patients increased risk post CPB? (7_)
An inherently poor LV
Poor myocardial protection
Poor coronary transference
Coronary air
Pulmonary HTN
Avoid LA dilation (careful with fluid boluses)
Milrinone
What congenital heart disease has common truncal valve and mixing of oxygenated and deoxygenated blood?
Truncus arteriosus
Truncus Arteriosus is a common CHD. True or False
FALSE.
Rare (1% of CHD)
In truncus arteriosus, common arterial outlet for ____ and ____ associated with single valve and VSD.
Aorta
PA
In TA, mixed blood at arterial level with high pulmonary blood flow leads to ____ and ____.
Heart failure
Pulmonary HTN
In TA, early surgery to separate pulmonary from systemic circulation and close VSD with ______.
Valve conduit
In TA, post-op mortality is high (5-25%) due to (4) things/.
Potential truncal valve stenosis
Coronary abnormalities
Pulmonary hypertensive crisis
Low birth weight
(MM) what hemodynamic alteration may worsen (increase flow through) a left to right intracardiac shunt?
An increase in SVR my increase left to right shunt, such as occurs in ASD
Avoid intervention that may increase SVR in a patient with ASD
(MM) What is a patent ductus arteriosus? When does the ductus arteriosus close?
PDA is abnormal persistence in the newborn of blood flow through the ductus arteriosus, an opening between the pulmonary artery and aorta.
Normally, the ductus arteriosus closes within a few hours to days after birth due to changes in the pressure of the pulmonary vasculature.
(MM) Name the physiologic factor most responsible for closure of ductus arteriosus after birth
Normal closure occurs in response to INCREASED ARTERIAL OXYGEN TENSION (PaO2) as well as reduction in circulation prostaglandins.
Realize that a # of other substances such as eicosanoids and factors such as PaCO2 and pH have been implicated, but INCREASED OXYGEN TENSION is the major factor
(MM) Is the shunts of a PDA right to left or left to right?
LEFT to RIGHT
With a patent ductus arteriosus, what CV changes occur?
A PDA allows blood to flow from aorta to PA.
Additional blood is deoxygenated in the lungs and returned to the LA and LV and causes increased workload on the left side of the heart and LV hypertrophy and increased pulmonary vascular congestion and resistance.
Most patients are ASYMPTOMATIC
(MM) What is the probable problem if the pediatric patient has a systolic and diastolic murmur?
PDA
A continuous systolic and diastolic murmur is a manifestation of PDA.
(MM) Where are pulse Oximeters placed on the neonate to monitor preductal and postductal oxygenation
PRE: pulse ox on RIGHT hand or finger
POST: pulse ox on LEFT foot or toe
(MM) What is the purpose of a preductal Oximeter in the neonatal patient undergoing cardiac surgery?
Measurements of arterial O2 sat taken at a PREDUCTAL location (right hand/finger) are a better index of NEONATAL CEREBRAL OXYGENATION than those taken at postductal location.
The R to L shunt at the ductus arteriosus persist some time after brith and this shunt may affect oxygen saturation readings, thus preductal placement of Oximeter is preferred.
Postductal may be used in addition to preductal to quantitate the severity of R to L shunt
(MM) Where should arterial BP be measured in a patient undergoing repair of a PDA?
Peripheral artery such as femoral (post-ductal)
Does blood shunt R to L or L to R through the VSD in Tetrology of Fallot
R to L shunt, permitting unoxygenated blood to mix with oxygenated blood, resulting in CYANOSIS
What pharmacologic agent decrease a R to L shunt in a TOF patient?
Phenylephrine increase SVR thus decreasing the magnitude of a R to L shunt.
How do CHD patients respond to slow HR
Reduced CO Hypoventilation Hypercarbia Hypoxia Rise in PVR
Sevo causes mild decrease in SVR. T/F
True
Mild to moderate CHD patients can tolerate careful induction of SEVO. T/F
True
Can mild-to moderate CHD patients tolerate induction with Sevo?
Yes
What is the induction of choice with young infants with severe CHD?
IV induction with high opiod doses (3-5 mcg/kg) fentanyl or more
Pancuronium and low dose Sevo/ISO
What is the difference in ISO and sevo?
Similar characteristics but ISO has much more pungent odor
Should Iso be used as an inhalation agent?
No
It triggers laryngospasms
Halothane has a very rapid uptake. T/F
True
What 3 things can halothane cause?
Hypotension
Arrhythmias
Bradycardia
Is it okay to use N2O for induction in peds cardiac anesthesia?
Yes N2O 70% with Sevo is okay
When should you avoid N2O in CHD patients?
Avoid N2O as maintenance in CHD patients because risk of intravascular air emboli and potential of increase in PVR
N2O is reported to increase PVR in adults, however less than _____ of N2O has little effect on PVR on infants?
50%
N2O may _________ microbubbles and macrobubbles and ____________ obstruction to blood flow in arteries and capillaries.
Expand
Obstruction
When should N2O be avoided??
In children with limited pulmonary blood flow, pulmonary htn, and depressed myocardial function
N2O largely decreases CO in infants T/F?
False, mildly decreases CO in infants
Ketamine is a good analgesic which increases what 3 things and why?
HR
BP
CO
Stimulating the release of endogenous catecholamines
When is ketamine a poor choice?
If tachycardia is undesired (aortic stenosis)
If catecholamine stimulation is already maximized (severe cardiomyopathy)
What is the IV dose of ketamine
1-2 mg/kg
Ketamine is thought to medley increase/decrease PVR in CHD children?
Increase
What drug has short acting induction and favorable hemodynamic profile with little effect on BP HR and CO?
Etomidate
Etomidate has increased mortality with continuous infusion because why?
Adrenal suppression
What can occur after a single dose of etomidate?
Inhibition of steroid synthesis can occur after single dose
Propofol induction causes what?
Decrease in SVR, BP an CO with variable effect on HR
Propofol is safely used in children with CHD but generally avoided as an induction agent in severe CHD because of its effect on ______ and ______.
SVR and BP
What patients should you avoid propofol in?
Patients with fixed CO (severe aortic or mitral stenosis) and severe hypotension
What infusions can you use during CPB to reduce risk of awareness?
Propofol and dexmedetomidine
Why is fentanyl a great choice in neonates and infants?
Because it provides excellent hemodynamic stability, with suppression of hormonal and metabolic stress response
Downside to fentanyl?
Pt often times needs to remain intubated
What is fentanyl often used in combinations with?
Midazolam, pancuronium with low Sevo/iso
How many more times potent is sufentanil than fentanyl?
5-10 times more potent
What drug is used at induction doses and may produce tachycardia and increase in CO, often desired to offset the vagotonic effect of high-dose opioid (fentanyl) and in CHD infants with fixed stroke volume?
Pancuronium
What drug is a very specific pulmonary vasodilator with minimal effect on systemic circulation?
Nitric Oxide
How does inhaled nitric oxide work?
It acts on guanylate cyclase to produce pulmonary vascular smooth muscle relaxation
Why is nitric oxide used in cath lab?
To assess reactivity of pulmonary vasculature to vasodilate in children with pulmonary HTN versus fixed pulmonary vascular obstructive disease
What does nitric oxide facilitate?
Operative planning and management
How is nitric oxide administered?
1-80 ppm (parts per million)
Usually 20-40 ppm
What needs to be checked for long term use?
Blood methemoglobin concentration
Flolan (Epoprostenol sodium) is a naturally occurring ___________, acts as a potent vasodilator/vasoconstrictor (SVR and PVR)
Prostaglandin
Potent vasodilator
What is flolan used for?
Thx primarily for pulmonary htn (PPH)
What does flolan cause in the lungs?
Bronchodilation
What does flolan inhibit?
Platelet aggregation
How is flolan metabolized?
Rapid metabolism via enzymatic degradation
Half life of 6 min
Common SE of flolan
Flushing
HA
N/V
Hypotension
When is flolan contraindicated?
In CHF d/t severe LV systolic dysfunction
What should you avoid when using flolan IV?
Avoid abrupt interruption of flolan IV
Don’t use the PIV (through which flolan is infusion) for induction
What is the dosage of flolan?
Nanograms/kg/min
MM
The pediatric patient is scheduled for a radiofrequency ablation of an aberrant conduction pathway (e.g. Wolff- Parkinson- White) syndrome. What is the general anesthetic typically required for this scenario?
Radiofrequency ablation is a non surgical approach designed to eliminate atrial or ventricular re-entrant tachyarrhythmias. The technique requires mapping and precision ablation of the aberrant pathway, using a radiofrequency ablation catheter. During the ablation, unexpected movement may result in catheter dislodgment and damage to normal conduction tissue; therefore, general anesthesia is usually required in younger children.
Anesthetic agents and technique should be chosen to maintain circulating catecholamines and avoid suppression of arrhythmogenesis, for identifying of the aberrant pathway.
Procedures in EP lab are complex and long duration with patients with multiple comorbidities T/F?
True
The EP lab is a unique situation in which arrhythmias are ____________ sometimes even ______________ so that they may be eliminated via ablation
Sought
Provoked
Isoproterenol (isuprel( is often used to introduce what?
Tachyarrhythmias during mapping
What medication should you avoid in the EP lab?
Medications that have antiarrhythmic properties
Lidocaine
Also avoid medication tha twill ameliorate the dysrhythmia or slow down the tachyarrhythmias ie opioids, volatiles, dexmedetomidine, etc
How should you do an anesthetic in EP lab?
Inhalation induction is okay but then convert to propofol infusion
How should you treat hypotension in EP lab?
With IV fluids and avoid phenylephrine, severe hypotension may be treated with vasopressin (however, discuss first with EP physician)
What is a atrioventricular canal repair?
Patch closure of atrial and ventricular communication to eliminate the intracardiac shunt
What is PA banding>?
Constrictive band placed around main PA to limit excessive pulmonary blood flow
What is a valvectomy?
Valve excision
What is a valvotomy?
Opening of stenotic valve
What is a valvuloplasty?
Valve repair
What is dextrocardia?
Birth defect where the heart is located on the R side of the body instead of the left. Patients with dextrocardia are often undiagnosed until they receive their first chest x ray or ECG.
What should you do if you encounter a patient with dextrocardia?
Place the ECG leads backwards
The L limb lead needs to be on the R otherwise the ECG will show inverted P and T waves
What should you do in a crisis with the defibrillating pads on patients with dextrocardia?
Place them in the traditional location
MM
List four congenital heart defects involved with tetrology of Fallot (cyanotic heart disease)
- VSD
- Right ventricular outflow tract (RVOT) obstruction (pulmonary stenosis)
- RV hypertrophy
- Overriding aorta: dextroposition ( to the right) of the aorta with overriding of the VSD
MM
What are the goals of anesthetic management for the patient who has tetrology of Fallot?
The goals of anesthetic management should be to maintain intravascular volume and SVR
Increases in PVR should be avoided
MM
An infant has tetrology of Fallot )cyanotic heart disease). Which of the following arterial blood gas parameters will NOT typically be changed: PaO2, pH, PaCO2?
pH and PaCO2 are likely to be in the normal range
PsO2 is usually markedly decreased (<50 mmHg)
During the case, oxygen saturation decreases, apparently because of increased shuntin. The patient has Tetrology of Fallot. What agents might be selected to decrease shunt and increase oxygen saturation?
IV fluid volume must be maintained with IV fluid administration since acute hypovolemmia will tend to increase the magnitude of the R -> L intracardiac shunt
An alpha- agonist drug such as phenylephrine must be promptly available to treat an undesired decrease in systemic blood pressure caused by a decrease in SVR
MM
List 3 conditions that increase the R -> L shunt (tetrology of Fallot)
Acidosis
Hypercarbia
Hypotension
In general, increase in PVR or decreases in SVR )caused by acidosis or hypercarbia) increase R -> L shunt
Volatile anesthetics and histamine release decrease SVR
MM
To what do preductal or postductal coarction of aorta refer?
Coarctation of the aorta refers to a discrete narrowing of the aorta immediately distal to the origin of the L subclavian artery
A preductal coarctation refers to a coarctation in a neonate or infant in which the narrowing occurs proximal to the opening of the ductus arteriosus
Postductal coarctations supposedly present in adulthood long after closure of the ductus arteriosus
MM
Should upper extremity blood pressure be monitored in the neonate with preductal coarctation of the aorta on the r or l arm?
Monitoring of blood pressure is best achieved in a patient with preductal coarctation by placing a catheter in the R radial artery
MM
Identify the best site to obtain ABG from in neonate?
The R radial artery
In addition to the ease of access, this site will reflect preductal oxygen saturation, which better reflects cerebral oxygenation
MM
What is the anesthetic concern for a pediatric patient undergoing repair of a VSD with significant pulmonary HTN?
The patient with an unrepaired VSD and irreversible pulmonary HTN often displays R -> L shunting through the VSD (Eisenmenger’s physiology)
Mainupulations that may increase PVR can cause rapid deterioration and include hypoxia, hypercarbia, acidosis, hypothermia, atelectasis, sympathetic stimulation and polycythemia
Early closure of VSD before 1 year old results in normal ventricular function and ejection fraction
MM
A R -> L intracardiac shunt is present in the patient with VSD with Eisenmenger’s syndrome. What hemodynamic alterations may worsen (increase shunt flow) to the R -> L shunt of VSD with Eisenmenger’s syndrome?
An abrupt increase in PVR or decrease in SVR is poorly tolerated in pt with VSD
Avoid intervention that increase PVR or decrease SVR in pt with R -> L intracardiac shunt
MM
Will a R -> L intracardiac shunt theoretically slow or accelerate inhalation induction? Is the effect clinically significant?
A R-> L intracardiac aunt theoretically slow inhalation induction, because less anesthetic is absorbed from the lung, and mixing will further dilute blood passing to the L, decreaseing the arterial concentration of the blood going to the brain, especially the less soluble agents
This effect is rarely problematic
MM
Will a R to L intracardiac stunt theoretically slow or accelerate intravaneous induction?
An IV induction will be theoretically accelerated with a R -> L shunt
MM
Will a L -> R shunt theoretically slow or accelerate e inhalation induction? Why is the phenomenon rarely evident clinically?
A L -> R shut should accelerate the speed of induction b/c the rate of transfer of anesthetic agent from the lungs to the blood is increase
Rarely evident b/c decreased delivery of anesthetic to the target tissues negates the increased uptake of agent with the L -> R shunt
MM
Will a L -> R shunt theoretically slow or accelerate IV induction? Why is this phenomenon rarely evident clinically?
IV induction should be slowed by L -> R shunt however unless CO is v poor the effect is clinically irrelevant
