Principles II Flashcards
Location of Glottis in neonates vs. adults
C3-C4
(adults have a lower glottis at C4-C5)
Describe the differences in Respiratory Systems of neonates
- poor respiratory control
- sensitive to respiratory depressant effects of opioids and inhalational agents
- high risk of post-anesthetic apnea
- 52-60 weeks post conceptual age
- 2-3x O2 consumption
- depressed CO2 response curve
- decreased energy reserves
- equivalent tidal volumes, but faster breathing
- prone to atelectasis
Describe the differences in Cardiovascular System in Neonates
- less compliant myocardium
- HR dependent
- immature SNS, so cardiac output can only increase by 30-40%
- preload insensitive
Describe the differences in the Hepatic System of Neonates
- functionally immature liver
- reaches adult levels within 1st few months
- longer half-life of drugs
Describe the differences in the Hematologic System of Neonates
- HbF makes up 75% of total hemoglobin
- Hemoglobin around 17 g/dL
How much blood loss can critically ill newborns take?
HCT > 35% or blood loss > 15%
Describe Heat Loss in Neonates
- increased body surface to weight
- non-shivering thermogenesis
Consequences of Hypothermia in Neonates
- hyperviscosity
- increased O2 consumption
- lactic acidosis
- depression of respiration, circulation, metabolism, and glucose levels
Ideally, how old should an infant be before surgery
greate than 60 weeks old if anemic and 50 weeks old if apenic
Size formula for Pediatric ETT
age/4 + 4
Pre-operative dose of Atropine prior to Sux
0.02 mg/kg
Dose of Succinylcholine in Pediatrics
2 mg/kg IV
or
4 mg/kg IM
Treatment for Post-Extubation Croup in Pediatrics
racemix Epi via nebulizer
(0.5 mL of 2% solution)
Treatment for Hypocalcemic Peds
1 - 2 mL/kg 10% calcium chloride
(or gluconate)
Treatment for Hypoglycemic Peds
250 - 500 mg/kg bolus of glucose (D25)
What may cause retinopathy of prematurity?
High O2 concentrations
Range of Hypoglcemia in Infants
< 30 mg/dL
Children with URI symptoms are at increased risk for ______ weeks after the onset of symptoms
- laryngospasm, bronchospasm, desaturation
4 - 6 weeks
Pre-operative dose of Versed for Pediatrics
0.25 - 0.5 mg/kg
Normal Systolic Blood Pressure in Pediatrics
- Newborn to 1 month
- 60 mmHg
- 1 month to 1 year
- 70 mmHg
- > 1 year
- (age * 2) + 70mmHg
Typical/expected diastolic Blood pressure
(equation)
2/3 x SBP
Normal Pulse for Pediatrics
- Newborn to 1 year
- 140 bpm
- 1 year to 4 years
- 120 bpm
- 4 years to 12 years
- 100 bpm
- > 12 years
- 80 bpm
Normal Respiratory Rates for Pediatrics
- Newborn to 1 year
- 40
- 1 to 4 years
- 30
- 4 to 12 years
- 20
- > 12 years
- 15
Why does inhalational inductino occur faster in pediatric patients?
higher minute ventilation and small FRC
Why do pediatric patients develop respiratory fatigue easily?
muscles of respiration poorly developed
Congenital Diaphragmatic Hernia (CDH)
hole in the diaphragm allows abdominal organs to move into the chest, which prevents the lungs from developing normally, resulting in pulmonary hypoplasia
What is the pulmonary problem in patients with CDH?
- compression of lungs leads to pulmonary hypoplasia
- arterial hypoxemia occurs because of right-to-left shunt through ductus arteriosus
- increased pulmonary vascular resistance
Which side does CDH usually occur?
Left
(75% of cases)
How is CDH usually diagnosed?
prior to birth by US
chest X-ray shows loop of bowel in chest
How is an infant with CDH treated immediately after birth?
- decompression of stomach with OG/NG
- supplemental oxygen
- AVOID PEEP
Intubation in patient with CDH
awake intubation
- do not let peak airway pressures exceed 25-40 cmH2O
- too high of pressures will cause pneumothorax
What size ETT should be used for a full term baby?
3.0 - 3.5
Formula for ETT depth
age/2 + 12
or
I.D. of ETT x 3
Which hand gives a pulse ox reading of preductal saturation?
right hand
Importance of avoiding hypothermia in CDH patients
hypothermia will increase PVR and increase right-to-left shunt, and increase O2 consumption and acidosis
What are the signs of a pneumothorax?
- decrease in lung compliance
- deterioration of oxygenation and blood pressure
In CDH surgery, once the hernia is reduced, should attempts be made to inflate the hypoplastic lung?
No
it is unlikely to expand and contralateral lung may be damaged by excessive positive pressure
Should glucose containing fluids be used to replace blood or for third–space losses?
No
Indications for CABG
- angina not controlled by medical treatment
- unstable angina or episodes of myocardial ischemia
- unacceptable angina, despite optimal therapy
- prinzmetal angina with coronary artery obstruction
- acute MI, intractable arrhytmias
How do you calculate left ventricular function?
- history of MI and angina
- symptoms
- dyspnea, nocturnal orthopnea, pitting edema
- Cardiac catheterization, angiography, and ECHO
What are the (3) major determinants of myocardial O2 consumption?
- myocardial wall tension
- contractility
- heart rate
Determinants of Coronary Blood Flow
- aortic diastolic pressure
- LVEDP
- patency of coronary arteries
- coronary vascular tone
Systemic Oxygen demand decreases ____% for every degree of temperature drop
9%
Normal Pulmonary Capillary Wedge Pressure
4 - 12 mmHg
(more than 18 mmHg reflects heart failure)
Common complications of Swan-Ganz catheter
- infection
- hematoma
- air embolism
- thrombosis
- catheter shearing and embolization
- arrhythmias
- pulmonary infarction
Complications of Swan-Ganz catheter from Subclavian approach
- pneumothorax
- hemothorax
- hydrothorax
Diagnostic uses of TEE
- Monitoring left ventricular filling and ejection
- Detection of hypokinesia, akinesia, and dyskinesia
- Detection of air embolism
- Detection of valvular regurgitation
- Analysis of congenital cardiac lesions
- Diagnosis of thoracic aorta pathology
- Diagnosis of cardiac tumors
- Detection of other cardiac lesions and cardiac tamponade
Cardiovascular effects of Volatile Agents
- depression of ventricular function
- vasodilation
- decreased CO and sympathetic tone
What should you do during sternal splitting?
stop ventilations and deflate lungs
Would you monitor pulmonary capillary wedge pressure continuously?
no
may cause pulmonary infarction
What anticoagulant would you give before CPB?
heparin in doses of 300 U/kg
- measure heparin activity with ACT
Heparin and ACT during CPB
- onset of ACT prolongation in radial artery occurs within 1 minute
- obtain baseline prior to heparin
- check ACT 3-5 minutes after heparin administration and then every 30-60 minutes
- no less than 300sec during normothermia and 400sec during hypothermia
Cardioplegia
hypothermic and hyperkalemic solution
- used to induce electromechanical dissociation
- infused between clamp and aortic valve
What should you check if the patient will not wean from CPB?
- adequacy of repair
- TEE
- hemodynamic variables
- institute pharmacologic therapy
Signs of Anaphylaxis
- hypoxemia
- rash or hives
- hypotension
- tachycardia
- broncospasm or wheezing
- increased peak inspriatory pressure (PIP)
- angioedema
Treatment for Anaphylaxis
- discontinue potential allergens and volatile agents
- 100% O2
- IV fluid bolus and epinephrine
- consider vasopressin
- Treat symptoms with albuerol, Epi, H1 antagonist and H2 antagonist
- consider intubation and IV access
Signs of Local Anesthetic Toxicity
- tinnitus or a metabolic taste
- altered mental status
- seizures
- hypotension
- bradycardia
- ventricular arrhythmias
- cardiovascular collapse
Treatment of Local Anesthetic Toxicity
- If pulseless, start CPR
- stop local anesthetic and avoid vasopressin
- call for intralipids
- 1.5 mL/kg bolus of 20% intralipid IV
Signs of Myocardial Ischemia
- depression or elevation of ST segment
- arrhythmias
- regional wall motion abnormalities
- chest pain in awake patient
Treatment for Myocardial Ischemia
- increase 100% O2
- treat hypotension (or hyper)
- beta blocker
Where does an AAA usually occur
beween renal and mesenteric arteries
Normal intraocular pressure
10 - 20 mmHg
What type of drugs should you avoid in glaucoma patients?
anticholinergics
Phenylephrine in Ophthalmic surgery
dilates pupil
Epinephrine in Ophthalmic surgery
decreases aqueous secretions
Ecothiophate
long-acting topical anticholinesterase
- needs to be off 2-3 weeks before surgery to allow plasma cholinesterase levels to return to normal
Acetazolamide in Ophthalmic surgery
diuretic used to lower IOP
- can cause hypotension if given too quickly
Preoperative issues in patients undergoing Ophthalmic surgery
- claustrophobic
- can they lie still on their backs
- do they cough a lot?
Strabismus
“cross eyed”
- imbalance of intraocular muscles
- surgery has high incidence of nausea and vomiting
- type of muscle disorder, so there may be a higher risk of MH
Pterygium
growth on surface of eye due to excess sun exposure
Ptosis
droopy eyelids
Orchiopexy
surgery to move an undescended testicle into the scrotum
- may need general and regional
- vagal response and nausea
Pectus Excavatum
congenital chest wall deformity that causes the chest to cave in
- respiratory problems and cardiac compromise
- restrictive lung disease
Mediastinal Mass Excision
- assess child’s ability to breath
- some may not be able to lay flat
- CPB and rigid bronchoscopy available
Wilm’s Tumor
Nephroblastoma
- most common liver cancer of children
VP shunt
- increased ICP
- high risk of latex allergy
Craniotomy
- children more likely to have infratentorial tumors
- fine movement and balance
- Risk of venous air embolism dur to beach chair position
Craniosynotosis
premature closure of a cranial suture
- increases ICP
- risk of blood loss and venous air embolism
NDMR in neonates
needs a higher dose inititally
smaller redoses and less often
Total body of water in newborns
70-85%
Trends in body compartment volumes from neonate to adult
total body water - decrease
intracellular fluid - same
blood volume - decrease
muscle mass - increase
fat - increase
Why are neonates more susceptible to the cardiovascular effects of inhalational agents?
- hearts are more sensitive
- rapid uptake and distribution
- right-to-left shunt has a slower rate of rise in arterial contraction
- MAC is lower in newborns than infants
Cardio differences in Neonates
less compliant, fixed stroke volume, HR dependent, decrease contractile mass, and decreased velocity
Atropine dose in neonates
0.03 - 0.05 mg/kg
(compared to 0.01 in adults)
doses less than 0.1 mg may produce paradoxical bradycardia!
Which narcotic will migrate more?
Fentanyl or Morphine
Morphine
it is more hydrophilic compared to Fentanyl which is lipophilic
Why is Pancuronium a good MR in children?
potent vagolytic
can increase HR
Which type of local anesthetics are more preferable in neonates?
esters
amides are metabolized in the liver, but their liver may not be well developed yet. Esters are metabolized by plasma esterases
Omphalocele
organs stick out through the belly button
organs stick out in a hole besides the belly button
gastroschisis
Pyloric Stenosis
narrowing of pyloris
(stomach to duodenum)
- presents 3-6 weeks of age
- dehydrated and nutrient deprived
- aspiration risk
- Needs an OG/NG placed
TEF
Transesophageal Fistula
Transesophageal Fistula
blind esophageal pouch connecting it to the trachea
Meningomyelocele
“Spina Bifida”
spinal canal and the backbone don’t close before the baby is born, letting the spine and membranes protrude through the baby’s back
PDA
Patent Ductus Arteriosus
Patent Ductus Arteriosus
large left-to-right shunt
Coronary Artery Disease
artherosclerosis of the blood vessels supplying the heart
- leads to myocardial ischemia
Risk factors for CAD
- genetics
- diet
- environment
- hypertension
- smoking
- diabetes
What part of the heart is most vulnerable to ischemia
left ventricular subendocardium
Drug of choice for coronary spasm
Nitroglycerin
Which venodilating drug decreases venous return and ventricular filling pressure?
Nitroglycerin
Which drug increases the MVO2 requirements due to increased coronary perfusion pressure?
Phenylephrine
Which CCB is good for SVT?
Verapamil
Normal Pulmonary Wedge Pressure
12
An ejection fraction < ____ indcates myocardial dysfunction
0.4
“LAMPS” before CPB
- Laboratory
- Anesthesia
- Monitor
- Patient
- Support
(7) Components of CPB
- circuit
- oxygenator
- pump
- heat exchanger
- primer
- anticoagulants
- myocardial protection
In CPB, blood is drained from the ____ and returned to the ____
right atrium, ascending aorta
Two types of Oxygenators in CPB
bubble and membrane
3 types of CPB pumps
roller, centrifugal, and pulsatile
Hypothermia during CPB
10 - 15 oC
Systolic BP should be reduced to _____ before aortic cannulation to reduce risk of aortic dissection
80-100 mmHg
What is the most likely cause of neurologic injuryafter CPB
emboli
with increased risk if hypotensive
Why should Versed be given before rewarming after CPB?
increased risk of awareness
Dose of Protamine on CPB?
1 mg/100 units heparin
(usually 3 mg/kg)
Risks of Protamine
hypotension and mast cell degraulation
Intra-Aortic Balloon Pump
deflates before systole to decrease afterload
inflates during diastole to increase coronary blood flow
Manifestations of Cardiac Tamponade
- hypotension
- equalization of diastolic filling pressures
- fixed stroke volume
- peripheral vasoconstriction
- tachycardia
- potential myocardial ischemia
