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creation of an opening thru which fluid can drain to reduce serous otitis media which is common in young children
skin growth that occurs in an abnormal location, the middle ear behind the eardrum. It is usually due to repeated infection which causes an ingrowth of the skin of the eardrum
separates middle from outer ear
ventilation tube placed in hole created by myringotomy, serves as a stent for the ostium
Patients with what condition have a high incidence of middle ear disease, needing PE tubes?
Due to the associated abnormalities of the cartilage and muscles surrounding the eustachian tubes.
When is emergence delirium risk the highest?
In cases where sevoflurane is used alone and not in conjunction with a narcotic
- onset 60-90 minutes
- peak 2-3 hours
What nerve is of major concern during tympanoplasty and mastoid surgery?
Must avoid muscle relaxants to allow for nerve monitoring
What nerve runs along the vestibular cochlear nerve?
the facial nerve
What level of the spinal cord are at risk for subluxation due to the laxity of the ligaments?
15 to 30% of these children have atlantoaxial instability
Down syndrome or achondroplasia
What is the most important anesthetic consideration for middle ear or mastoid surgery?
airway must be absolutely secure
Max does of epinephrine
Why would you want to do a light anesthetic on cochlear implants?
B/c the surgeon needs to be able to test the stapedius reflex
What has to happen for the ossicular chain to stiffen?
The stapedius stiffens the ossicular chain by pulling the stapes of the middle ear away from the oval window of the cochlea and the tensor tympani muscle stiffens the ossicular chain by loading the eardrum when it pulls the malleus in toward the middle ear
How do inhalational anesthetics affect the stapedius reflex threshold?
Increasing the concentration increases the reflex threshold, making it more difficult to test to see if it's working
What is the major concern for endoscopic sinus surgery?
They will vomit blood on emergency if there's a lot of bleeding.
- Throat pack- document it to remember to take it out
- Use a cuffed tube
- suck stomach out before waking up
- Surgeon may use: oxymetazoline, phenylephrine, cocaine, or dexamethasone
Wake up quick to reduce aspiration chance
Children who require endoscopic sinus surgery frequently have these conditions
What might tonsillar hyperplasia lead to?
- Chronic airway obstruction resulting in:
- CO2 retention
- Cor Pulmonale
- Faliure to thrive
- swallowing disorders
- speech abnormalities
Recite the four goals for adentonsillectomy
- 1. provide smooth atraumatic induction
- 2. provide surgeon with optimal operation conditions
- 3. establish IV access for volume expansion and meds
- 4. provide rapid emergence so child is awake and able to protect recently instrumented airway
What pressure for leak is the best for adenotonsillectomy?
20 cm H2O
What are the complications that can occur with LA infiltration into the tonsillar fossa?
- Intracranial hemorrhage,
- bulbar paralysis,
- deep cervical abscess
- cervical osteomyelitis
- medullopontine infarct
- cardiac arrest
Choanal atresia or stenosis
narrowing of the nasopharynx
may present as cyanosis at rest that resolves with crying or placement of an oral airway
- Vertebral abnormalities
- imperforate Anus
- Tracheoesophageal fistula
- Radial aplasia
- Renal abnormalities
esophaleal atresia and tracheosophageal fistula associated
What is the most common form of tracheoesophageal fistula?
esophagus ends in a blind pouch with the distal end of the esophagus connected to the trachea just above the carina
Foramen of Bochdalek
herniation site of abdominal organs into the thorax
toward dorsal side
where 90% of the herinations in the diaphragm occur
How should a patient with congenital diaphragm herniation be positioned?
affected side down to decrease weight on mediastinum and heart
rapid low TV to avoid barotrauma and potential for pneumothorax
What is the use of NO in pediatrics?
Nitric Oxide is a specific vasodilator of the pulmonary vascular bed
What is the main cause of Congenital diaphragm herniation mortality?
Hypercarbia after surgery indicates ventilation is not occurring and there is a 90% mortality rate when this occurs
olive sized mass in pyloric region
non-bilious vomitus= no duodenal contents b/c the stenosis
alkaline urine initially, then becomes acidotic contributing to the metabolic alkalosis
Which would you rather be? Acidotic or alkalotic?
- acidosis is better because the tissues still get oxygen b/c of the right shift of the oxyhemoglobin dissociation curve.
- Left shift (alkalotic) makes the HGB hold onto the oxygen more, so the tissues don't get the oxygen b/c the HGB is hogging it
How may pyloric stenosis patients present?
What other conditions are duodenal and ileal obstructions associated with?
- atrioventricular canal
What kind of vomit can you expect to see with duodenal atresia?
double-bubble sign formed by air contrast of the dilated stomach and proximal duodenum
3-5% of term infants, and 30% of premies
5-15% in infants under 1500 grams
stop feeding, decompress abdomen, ABX, dopamine in increase CO and improve intestinal perfusion
- Avoid inhalational agents
- Awake intubation
oompalocele and gastroschisis
defect in abdominal wall
herniated viscera are covered with a membrane sac
oompalocele are in a sac
SaO2 in lower extremities may differ from upper extremities
hemodynamic changes at birth
- decreased pulmonary vascular
- Ductal closure
- Decreased volume load
- Eliminated umbilical vein
- Output diminishes 25%
Hemodynamic changes at birth
- Increased afterload
- placenta eliminated
- ductal closure
- increased volume load
- increased pulmonary venous
- output increases nearly 25%
- Transient left to right shunt
- at ductus
What are the three fetal
Ductus arteriosus closure facts
closed in 58% of neonates by day 2, and 98% by day 4
- Initial closure functional due to pressure differences and increased oxygen
- concentration. Reduction of circulating prostaglandins with placental
In what percentage of adults does the foramen ovale remain patent?
Does the fetal heart have more or less optimal contractile components than the adult heart?
The Frank-Starling Law doesn't work as well in fetal cardiac systems
When I say t-tubule and sarcoplasm reticulum, you say
Blood products contain citrate, which chelates with circulating calcium thus reducing available Ca for myocyte use
How can neonates modify their CO to adjust for their high metabolic rate?
Stroke volume and heart rate can be altered
These components are supercharged just to be normal
Is the SNS or PNS more developed in neonates?
The PNS is more developed
Thus, sux and DL can cause marked responses to vagal stimuli
Why would acidosis prolong transitional circulation?
Acidotic patients are ususally having trouble with systemic vascular resistance so the right side pressure is greater than the left side pressure, leading to right to left shunt
Acidosis potentiates a production of natural NO, which creates a state of hypotension due to vasodilation
Conditions prolonging transitional circulation
- pulmonary disease
- congenital heart disease
- high altitude
- prolonged stress
What three means do congenital heart malformations incur pathophysiological cost?
- Volume loads
- Pressure loads
Structural defects that promote left ventricular flow to the pulmonary circulation trigger:
- Increased adrenal catecholamine output
- increased renin and angiotension production
- expanded intravascular volume
- constriction of noncritical vascular beds to compensate for the lost systemic flow by increasing total left ventricular output
These manifestations are also seen in massive hemorrhage...
Left to right shunts impose an ????????? volume load on the heart
Which septal defect is the worse one? Atrial or ventricular?
Signs and symptoms of congestive heart failure in infants:
- grunting respirations
- nasal flaring
- chest retractions
- poor feeding
- poor growth
In children with CHD in which volume is the issue, what is the implication of anesthetic agents?
These infants demonstrate greater vulnerability to the myocardial depressant effects
WHAT causes increased pressure load to a neonatal heart?
- Obstruction in the outflow tract,
- semilunar valve, and or great artery
what can cause volume load problems in neonatal hearts?
Intra-atrial and ventricular septal defects
What two distinct pathophysiologic mechanisms cause systemic hypoxemia?
right to left shunt
pulmonary venous return
Tetralogy of fallot
- Narrow pulmonary artery
- Aorta is overriding the VSD
- intra-ventricular septal defect
- right ventricular hypertrophy
Is a right to left shunt lesion
Alpha, Beta, dopaminergic receptors
Directly stimulates cardiac beta-1 receptors and provokes release of norepinephrine from cardiac sympathetic nerve terminals
Why won't neonates respond to ephedrine?
Because their sympathetic system is too immature to adequately respond
structural analogue of isoproternol
may be a better choice in CHF and cardiogenic shock b/c the actions of dobutamine do not depend on endogenous catecholamine stores
relatively selective beta agonism
pure, non-selective B-adrenergeic agonist
More beta-1 than beta-2
- Good for heart transplants
- Increases HR and contractility and causes vasodilation in mesenteric, renal, and skeletal muscle tissue beds
alpha, beta1, beta2 adrenergic agonist effects
Larger doses causes alpha induced vasoconstriction
is direct, does not depend on catecholamine stores
pure alpha adrenergic agonist
goal is peripheral vasoconstriction
Can cause compensatory decrease in HR (Bainbridge reflex)
0.05-0.2 mg/kg slowly
Non-selective beta blocker
SE: bradycardia, hypotension, worsening of myocardial pump function, AV block, bronchospasm, depression, fatigue
repeat dose q 5-10 minutes
100-500 mcg/kg loading dose over 5 minutes
50-250 mcg/kg/min infusion
metabolism by plasma and RBC cell esterases
0.5 to 1 mcg/kg/min infusion with max of 6-10 mcg/kg/min
arterial and venous vasodilator
What is the metabolite of nitroprusside infusion?
can occur when nitroprusside at >4mcg/kg/min and or used > 2-3 days
What is the antidote for cyanide poisoning?
Amyl nitrate followed up with methylene blue
Methylene blue b/c of the methemoglobinemia induced by the amyl nitrate
Nitroglycerin infusion rate
predominantly venous dilation
Used for cooling and rewarming after bypass
At what levels may the dural sac extend to in infants?
S3 or S4
What is the major complication for caudal anesthetics?
Doses for caudal blockade
0.5 ml/kg for lower extremity or perineal surgery
0.75 ml/kg for T-10 level
1ml/kg for lower thoracic level
Addition of preservative free MSO4 to caudal block for 18-24 hour postop pain relief in the following doses:
Perineal surgery: 50mcg/kg
Mid abdominal incision: 60 mcg/kg
Why might clonidine be beneficial to add into the caudal block mix?
- Less respiratory depression
- Less N/V
- Less itching
- Similar/prolonged analgesia vs. morphine
How is correct placement confirmed for caudal blocks?
- ease of injection
- negative aspiration
- radiographic imaging
- nerve stim. thru catheter
What percentage of children with congenital heart disease have surgery within their first year of life?
25% have surgery within the first month
WHat are the goals for preanesthetic visit for CHD patients?
- 1. medical assessment
- 2. administering premedication
- 3. providing information
- 4. creating a relationship with the child and family
- 5. formulating an anesthetic plan
What is the most common
premedication used for heart children?
How do children with cyanotic
heart defects compensate for chronic hypoxia?
- Increased erythropoesis
- increased circulating blood
- metabolic adjustment of 2,3
At what HCT does surgical
hemostasis becomes a problem
- Excessive viscosity impairs microvascular perfusion & outweighs the
- advantages of increased oxygen carrying capacity
those in which size and direction of shunting thru abnormal cardiac communications depend on the relationship between pulmonary vascular resistance and systemic vascular resistance and are thus variable
those in which shunting is relatively independent of the relationship between pulmonary vascular resistance and systemic vascular resistance
Name 5 types of dependent shunts
- simple atrial septal defect
- simple ventricular septal defect
- aortopulmonary windows
- other systemic to pulmonary shunts, like Blalock-Tassig
Name several types of obligatory shunts
- common AV canal defects
- systemic arteries and veins (AV fistula)
- tricuspid or mitral atresia
- aortic or pulmonary atresia
Obligatory shunts must have another dependent shunt at another level
When the pressure differential on two sides of a dependent shunt becomes very great, it takes on the characteristics of an ??????? shunt
communications are small, the size of the defect itself limits shunting and considerations of relative PVR and SVR become correspondingly smaller in determining the amount of shunting
Why is hemostasis impaired in the neonate?
Vitamin K-dependent coagulation factors are only 40-66% of normal values
When introducing the volume of the primer for cardiac bypass, what values are notably affected?
Fibrinogen is decreased by 50%
Platelet count decreased to 30% of pre-bypass levels
What is the dose of platelets?
What does cryopricipate provide?
von Willebrand factor
Of these three choices, which 2 are best to administer to neonates?
Platelets, cryo, or FFP
Platelets and cryoprecipitate
What are the 3 identified antifibrinolytics used in pediatric cardiac surgery?
- EACA- e-aminocaproic acid
- TA- tranexamic acid
What benefits does ultrafiltration provide during and after cardiac bypass?
- increasing the HCT
- concentrating the clotting factors and platelets
- increasing blood pressure and reducing pulmonary vascular resistance
- removing inflammatory mediators
What dose DDAVP do
increases plasma levels of factor 8 and von Willebrand factor
Dose is 0.3 mg/kg
When might EtCO2 monitoring be off?
When cyanotic lesions cause V:Q mismatching
Of the following three sites, which most truly matches the brain temperature?
1. Tympanic membrane
tympanic membrane and rectal sites overestimate the temp. of the brain
Children with what kind of shunt will experience slower induction with inhalational anesthetics?
cyanotic right to left shunts with reduced pulmonary blood flow
What two factors are related to myocardial damage during by-pass?
Duration of the aortic cross clamp
effectiveness of the myocardial protection
What two drugs are used during cardiac surgery to control blood pressure?
Phenylepherine to increase
Phentolamine to decrease
What should the ACT be after giving heparin and before going on bypass?
At least 3 times the baseline
What is the dose of heparin for cardiac bypass?
Will Sevoflurane exacerbate the shunt between the right and left sides of the heart thru an ASD or VSD when given in standard concentrations in 100% oxygen?
Why should nitrous oxide be avoided in children with CHD?
Because the risk of enlarging intravascular air emboli and the potential to increase PVR
WHat are the doses for ketamine?
- IV 1-2 mg/kg
- IM 5-10 mg/kg
What three manifestations of ketamine use might not be that desirable in cardiac kiddos?
increases in BP, HR, and CO
When should propofol be avoided?
in those patients with a fixed cardiac output such as severe aortic or mitral stenosis b/c it might cause severe hypotension
What is the order of preference of induction techniques, starting with the most preferred?
- 1. IV
- 2. INH
- 3. IM
- 4. intranasal, rectal, and SQ
IV has the greatest margin of safety
What is the most common septal defect?
ventricular wall defect
Name 5 Left to right shunt types
- 1. ASD
- 2. VSD
- 3. PDA
- 4. endocardial cusion
- 5. aortopulmonary window
What is the equation to figure SVR?
SVR= (MAP-CVP) / CO
In left to right shunts, what relationship between PVR and SVR increases PBF?
SVR > PVR = increased PBF= pulmonary congestion=CHF
when the PVR > SVR, a right to left shunt develops and Eisenmenger's syndrome results
What is the goal for Left to Right shunts?
Decrease SVR and Increase PVR to decrease the L to R shunt
- positive pressure ventilation and Peep Increases PVR
- Inhalational agents decrease SVR
Remember ketamine increases SVR
Name 4 right to left shunts
- 1. tetralogy of Fallot
- 2. Pulmonary atresia
- 3. tricuspid atresia
- 4. Ebstein's anomaly
Right to left shunts involve pulmonary vascular resistance that is greater than systemic vascular resistance, which results in decreased pulmonary blood flow and hypoxemia and cyanosis
What are the goals for right to left shunts?
Increase Pulmonary blood flow by decreasing pulmonary vascular resistance and increasing systemic vascular resistance
What is the most common right to left shunt?
acute cyanosis and hyperventilation
factors such as decreased BP and SVR should be avoided to not have tet spell under GA
What do you do for a tet spell?
- Knees to chest
- increase blood volume
- increase inspired oxygen concentrations
- increase SVR with neosynephrine
- lower PIP
- increase level of sedation
- Beta-adrenergic blockade
What are complex shunts?
they produce both cyanosis and CHF
continuous mixing of venous and arterial blood: SaO2 will be about 70-80%
Name several types of complex shunts
- truncus arteriosus
- transposition of the great vessels
- double outlet right ventricle
- hypoplastic left heart syndrome
- total anomalous pulmonary venous return
What is the procedure that is the first stage for hypoplastic left heart repair?
The norwood procedure
What procedure is used to correct transposition of the great vessels defect?
either valvular stenosis or vascular bands
decreased perfusion and pressure overload of corresponding ventricle
Name some types of obstructive lesions
- aortic stenosis
- mitral stenosis
- pulmonic stenosis
- coarctation of the aorta
- interrupted aortic arch