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Anesthesia Principles III
Pediatrics- Neonatal anesthesia, Pediatric Pharmacology
96
Medical
Graduate
07/26/2010

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Cards

Term
What is the definition of prematurity? About how much do they weigh?
Definition

*Less than 37 weeks

*2.5-3.5kg at birth

Term
What constitutes moderate prematurity?  What is the average weight?
Definition

*31-36 Weeks

*2.5kg

Term
What is considered severe prematurity?
Definition

*22-30 weeks

 

Term
What are the major causes of premature neonatal death?
Definition

*Intracranial hemorrhage

*Sepsis

*Respiratory Distress

Term
What deficits does the neonate have?
Definition

*Lack the ability to maintain body temperature *Sucking

*Swallow

*Eat

*Sustain life

Term
What is often the cause of prematurity?
Definition
*Asphyxia in utero
Term
What is often the causes of asphyxia in utero?
Definition

*Stress leads to anaerobic metabolism and metabolic acidosis

*Causes include: 

-Antepartum hemorrhage

-intrauterine infection

-breech delivery

-RDS

Term
What is the occurrence of respiratory distress for the neonate born by C/S?  What are the survival rates and what are they related to?
Definition

*Respiratory distress occurs 3x more often with C/S than vaginal delivery

*90% of babies 900-1000g survive

*70% of babies <750g survive

*Survival rate is related to surfactant and steroid use

Term
When does brown fat develop and increase in mass?
Definition

*Brown fat develops at 26-30

*Increases in mass 3-6 weeks after birth

Term
How does a child regulate temperature up to 2 years of age?
Definition
*Nonshivering thermogenesis
Term
*What infants in particular have a central problem with temperature regulation?
Definition

*Hypoglycemic infants

*CNS damaged infants 

Term
How does heat water loss occur easily?
Definition
*With use of radiant heat warmers
Term

What is bronchopulmonary dysplasia (BPD)?

 

Definition
*A lesion of prematurity: Parenchymal abnormalities, pulmonary fibrosis, acquired lobar emphysema, reactive airway disease, apnea, V/Q mismatch, sometimes associated with tracheo-bronchomalacia.
Term
What are the causes of BPD?
Definition

*Maldistribution of ventilation and perfusion

*Hypercarbia

*Hypoxemia

*Prolonged ventilation

*Fluid overload

*Infections

*Premature lungs

*barotrauma

*O2 toxicity

*often associated with PDA

*Pulmonary air leak

Term
What is the treatment for BPD?
Definition

*PEEP

*Diuretics

*PaO2 50-70mmHg

*Albuterol

*Ventilate with room air

*Keeps SpO2 87-92%

Solumedrol 

*limit fluids

Term
How do premature infants with apnea respond to anesthesia? When are infants with apnea discharged home?
Definition

*Premature infants prone to apnea do not breath under anesthesia and must be ventilated beginning with induction

*Preterm infants need 12 hours of apnea free discharge home 46-50 weeks PGA

Term
Why is anemia common in preterm infants?
Definition
*Because they have a reduced ability to produce RBC's 
Term
Where should preterm infant Hgb be kept?  What Hgb is more likely to prevent apnea?
Definition

*Hgb should be kept at 10-15g

*A hgb of 14-15 is more likely to prevent apnea 

Term
What is ROP and why does it occur?
Definition

*Retinopathy of Prematurity (Retrolental Fibroplasia)

-Retinal damage due to prematurity

-Require multiple OR visits for EUA and for phototherapy

*Occurs d/t small infants being exposed to O2, their small vessels in their eyes bleed & scar, eventually detaching the retina.

Term
What does retinopathy of prematurity often coexist with?
Definition
*Bronchopulmonary dysplasia (BPD)
Term
Why are premature infants more apt to an intraventricular hemorrhage?  Which are associated with poor outcomes?
Definition

*More apt d/t premature neurovascular bed and fluctuations in BP

*Poor outcomes associated with Grade III and IV, which almost always require VP shunts

Term
What is necrotizing enterocolitis?  What are the implications?
Definition

*Perforated bowel due to infection and decreased perfusion

*It is an emergency case: laparotomy

*Can have massive blood loss

*Difficulty maintaining normothermia

Term
What are the hemodynamic changes associated with a Patent Ductus Arteriosus (PDA) and how is it treated/managed?
Definition

*PDA causes pulmonary congestion d/t a left to right shunt

*Require increased ventilatory support

*LV failure--> CHF

*Treatment with Indomethocin before surgical repair

*Can cause renal and PLT dysfunction

*Dopamine may be necessary until correction of PDA to improve CO

*Left thoracotomy for closure

Term

A PFO is a common lesion of prematurity, what can t

his cause and how is it treated?

Definition

*Can cause primary pulmonary HTN

*Reduce PVR

*Deair all IV lines

*Adequate oxygenation is necessary to maintain PVR

*Pulmonary vasodilators include O2, tolazoline, PGE1, NO, ECMO

Term
What maternal factors can effect the fetus at birth?
Definition

*Pregnancy problems

*Drug use with pregnancy

-look for in baby: agitation, tremors, poor feeding

-barbiturates: seizures

-diazepam and methadone: symptoms take 5-10 days to show

-Cocaine: pulmonary hypertension, prematurity, bowel perforation

*ASA and Tylenol-Pulmonary HTN, persistent fetal circulation

Term
What events during birth can be significant for the anesthetist to know preoperatively?
Definition

*Asphyxia at birth- effects may still be present and autoregulation of cerebral blood flow may be absent

*Shoulder Dystocia- sudden increases in blood pressure may cause ICH.

Term
What aspects of an infant are important to for assessment of their current status?
Definition

*VS (MAP~ gestational age up to 41 weeks)

*Respiratory status- on the vent?

*Fluids, IV, Feedings- PICC, use 1cc syringes for flushes

*Weight- is current less than birth weight?

*U/O

*Medications

*Presence of PDA

*Presence of PFO

*Electrolyte abnormalities not uncommon

*Clotting factors will be abnormal

*Thrombocytopenia (<10,000) will not transfuse unless surgery is planned

Term
What fluid is usually used in the NICU until TPN can be started?
Definition
*A glucose solution
Term
What is defined as hypoglycemia in a term infant and in a preterm infant?
Definition

*Term infant- <30

*Preterm infant- <20

Term
How is hypoglycemia typically treated in the OR?
Definition
*BS less than 45 will be treated with 1-2mL of D10W
Term
______________  causes increased interval between drug dosing.
Definition

*Renal immaturity

*increased dose = increased interval

*Initial doses of some medication are higher to achieve therapeutic blood concentrations

*Prolonged excretion of penicillin, gentamycin, pavulon

Term
Sodium retaining ability develops at about __________  weeks.
Definition
*32
Term
Why does a peripheral nerve stimulator not work in young children?
Definition
*Due to lack of myelination
Term
Where should the pulse ox(s) be placed on an infant?
Definition

*Preductal- on right hand

*Postductal- on left food or left hand

Term
What monitor should not be used in the infant?
Definition
*Esophageal stethoscope, it may perforate the esophagus
Term
__________  number may not be reflective of actual __________  look at the waveform.
Definition

*EtCO2

*PaCO2

Term
What agents should be used for the neonate during induction?
Definition
*STP 1mg/kg with Pavulon or Norcuron and Atropine
Term
What should the anesthetist consider during maintenance for the neonate?
Definition

*Will require less than full term infants but don't give too little, patient could get an intracranial hemorrhage

*Inhaled anesthetics causes more hypotension in preterm neonates.

*Have 5% albumin available for volume

*You may need PRBC's if low Hct

*Use room air when possible 

*If using an umbilical catheter- is it above the diaphragm or below?

Term
What should the anesthetist consider during the recovery period for a neonate?
Definition

*Preterm infants <44 weeks gestation will develop post op apnea 

*Patients should be monitored for 24 hours post op

*Less than 50 weeks PGA (Post Gestational Age) not considered outpatient candidates

*Transfer patient in an isolette

Term
What are the steps in Neonatal resuscitation?
Definition

1.Position neck roll

2. Open airway

3. Suction if necessary

4. Mask with mouth open watch that tongue is not occluding

5. If heart rate>100 continue ventilation

6. If heart rate <100 start CPR and reposition airway/mask

7. If HR below 80 continue PPV and do chest compressions

-1 finger breadth below nipple line, using 2 fingers

-1/2 to 3/4 compression depth

-Accompanied by ventilations, ratio is 3:1 or 90 compressions to ventilations in 1 minute.

8. Give Epi (0.1-0.3mL/kg of a 1:10,000 solution- every 3-5 minutes as necessary)

9. If prolonged arrest give NaHCO3

10. If suspicion of acute blood loss or signs of hypovolemia give blood or volume expander

 

Term
What are the two indications for intubating a neonate?
Definition

*Prolonged bag and mask ventilation

*Bag and mask is ineffective

Term
What is the correct ETT size and suction catheter size for a <1000g neonate?
Definition

*2.0 ETT & 5-6 french suction catheter

 

Term
What is the correct ETT size and suction catheter for the 1000-2000g neonate?
Definition

*2.5 ETT

* 6 French suction catheter

Term
What is the correct ETT size and suction catheter size for the 2000-3000g neonate?
Definition

*3-3.5 ETT

*8 French suction catheter

Term
What is the correct ETT size and suction catheter size for the >3000g neonate?
Definition

*3.5-4.0 ETT 

*8 French suction catheter

Term
What formula can be used for the Neonate to calculate the depth of the ETT?
Definition

*6+weight (kg)

*Ex: Neonate weight 500g=0.5kg

0.5+6=6.5cm

Term
When is pharmacologic maturation achieved?
Definition
*6 months of age
Term
What is different about drug absorption in the pediatric patient?
Definition

*Protein binding is less

*RBC binding

*Tissue Volumes

*solubility is more because of larger ECF and blood flow to the tissues

Term
What is different about drug distribution in the pediatric patient?
Definition

*Uptake is higher- the breathe faster

*Higher alveolar ventilation 

*low FRC higher CO to vessel rich groups

*Rapid lung wash in/wash out

*Different muscle composition

*Lower plasma albumin

*Low alpha acid glycoprotein

*Large volume of distribution

Term
The blood brain barrier is ________ in the infant.
Definition
*Immature
Term
In the infant the TBW is _________, ECF is _________, Brain flow is _________, Fat is __________ and muscle is _____________.
Definition

*TBW increased

*ECF increased

*Brain flow increased

*Fat is decreased

*Muscle is decreased

Term
How does the tissue volumes and blood flow differ in the pediatric patient as compared to an adult?
Definition

*Brain volume is increased

*Brain flow is increaed

*Splanchnic volume is increased

*Renal flow is decreased

*Muscle volume is decreased

*Muscle flow is decreased

Term
The neuromuscular system is immature until ________ months.
Definition
*Two
Term
How does the immature immune system effect the infant?
Definition

*Preterm infants have posttetanic exhaustion 

*Diaphragm and intercostals innervated mostly by type II fast twitch fibers that fatigue easily

*Rate of synaptic transmission is slower due to the immature myelination

Term
What are the differences between an adult vs. infants neuromuscular junction?
Definition

Infant Adult

Gamma subunit           Epsilon Subunit

Junctional and extrajunc.       Localized to end plate

Unstable half-life 24h Shorter opening time

Long open time 2-10x>

Agonists dep. easier    Agonists dep. less easy

 

 

 

 

 

Term
Infants are unable to concentrate urine or clear large volumes due to ____________.
Definition
*Low GFR
Term
What is different about the renal system in the infant?
Definition

*high renal vascular resistance for 1-3 days after birth

*At 9 months 80-90% of GFR is complete

*Proximal tubule is functioning around 4-5 months

Term
How is the hepatic system different in the infant?
Definition
*Development takes place postnatal rather than gestational including cytochrome p450 and phase I and Phase II pathways and enzymes
Term
Why is there a rapid uptake and distribution of inhalational agents in infants in children?
Definition

*Lower FRC

*Higher respiratory rate

Term
How long does it take for the infant, child, and adult to reach equilibration in terms of an inhalational agent? (IE: Fe=Fi
Definition

*Infant- 25 minutes

*Child- 30 minutes

*Adults- 60 minutes

Term
How does blood gas solubility, Body comp., Alveolar ventilation, CO/CI, FRC, and lung wash in differ in the infant?
Definition

*Blood gas solubility changes over development

*Body composition is low muscle and fat

*Alveolar ventilation is high

*CO/CI is high

*FRC is low

*Lung wash in is rapid

Term
How does the presence of a right to left shunt effect an inhalation induction?
Definition
*Slows Inhalation induction
Term
How does a left to right shunt effect an inhalation induction?
Definition
*Shunt flow dependent, no real change with IH induction
Term
Why may an infant need a higher amount of inhalational agent?
Definition
*Due to their higher metabolic rate and oxygen consumption
Term

When does MAC peak?

 

Definition

*At 3 months of age

*The smaller the child the more rapid the uptake into the alveoli, high concentrations may cause hypotension in infants and young children. (Esp. those with cerebral palsy)

Term
What is the MAC for Halothane in an infant?
Definition
*0.87
Term
What is the MAC of Isoflurane in the infant?
Definition
*1.6
Term
What is the MAC of sevoflurane in the infant?
Definition
*3.3
Term
What is the MAC of desflurane in the infant?
Definition
*9.2
Term
What details of Halothane are important to know when using in children?
Definition

*Sensitizes the myocardium to catecholamines

*Very cardiac depressive

*Should not be used in patients with elevated ICP

*Halothane Hepatitis happens LESS frequently in children than adults

*High blood gas solubility 2.4

*SLOW inhalation induction 5-6 minutes

Term
Should forane be used for induction in children?
Definition

*NO

*Very pungent odor, not used for IH induction

*Less cardiac depression than with halothane

Term
What are important characteristics of Sevoflurane?
Definition

*Less irritating to airways

*Fast IH induction secondary to low blood gas solubility (0.69).  

*May see tonic/clonic movements with induction.

*Can cause post operative agitation 

*Very expensive

*Great for short cases and mask cases

Term
Should desflurane be used for inhalation inductions?
Definition

*No.

*May still have emergence agitation (can be slightly prevented by giving opioids to provide adequate analgesia during recovery from anesthesia)

*Not used at CHM except in idiopathic spinal fusions

Term
What peds cases should N2O use be avoided in?
Definition

*Tympanoplasty cases, bowel cases, eye muscle surgery cases or cases where N/V are frequent

 

Term
What is Brutane?
Definition

*"Brute force"- a 4 point restraint system to keep the patient and staff safe if necessary

*Use as a last resort

Term
What are the cardiovascular effects of inhalational agents in infants in children?
Definition

*Baroreceptor response depressed (a decrease in BP without a decrease in HR)

*Incomplete adrenergic penetration of myocardium

*Dose dependent depression of the myocardium

Term
Why is there prolonged sleep time with barbiturates in children?
Definition

*Increased brain blood flow

*Immature BBB

*Decreased metabolism of barbiturates
*Increase in volume of distribution

Term

In children benzodiazapines have ______ respiratory depression and ________ amnesia

 

Definition

*Mild

*antegrade

Term
Which agent is hypnotic, depresses GABA, no analgesic properties & causes pain on injection- use a narcotic with it.  It has less myocardial depression than other agents.
Definition
*Etomidate
Term
In which children is use of Etomidate contraindicated?
Definition

*Adrenal insufficiency

*Epilepsy

*Acute porphyria

*Children <2

Term
Why is Etomidate contraindicated in children <2?
Definition
*Because Etomidate is 72% bound to albumin, in infants there will be more free drug if hypoalbuminemia is present.
Term
Use of propofol in children causes........
Definition
*A decrease in SV, MAP & SV causing a profound drop in BP, dose decreases over childhood
Term
What is a derivative of PCP, should not be given to hydrocephalus patients, or any patient with increased ICP, and should be given with an anticholinergic?
Definition
*Ketamine
Term
What pharmacologic agent should be used with caution in the first month of life?
Definition

*Opioids

*Unless they are staying on the ventilator

*Crosses the BBB, highly lipophilic, higher T1/2 life

Term
What should be known when using succinylcholine in the pediatric patient?
Definition

*MUST give atropine with it!

*Higher dose requirement d/t increased TBW, ECF, and volume of distribution

*Fasiculations are absent in children <3 years old d/t immature NMJ

*Diaphragm is paralyzed at the same time as the peripheral muscles

*Rapid onset and recovery

*Watch for patients with high K, high IOP or high ICP

*Phase II block on second dose 

*MH precautions- secondary to muscular dystrophy

*Cardiovascular effects: Bradycardia, asystole, hyperkalemia

Term
Why are children most sensitive to NMDRs?
Definition

*Due to poorly developed musculature, immature NMJ, lean muscle mass

*Can be potentiated by aminoglycosides (ie. Gent)

Term
In what situations is the use of Pancuronium, Vecuronium, Cisatricurium, or Rocuronium preferred over the use of another?
Definition

*Pancuronium: may be preferred for CV support in preterm infants and cardiac babies

*Vecuronium: long acting in children up to 2 years of age

*Cisatricurium: especially for renal patients

*Rocuronium: for RSI

Term
What should be use in an infant for reversal agents?
Definition

*Onset is much quicker than adults, same duration.

*Consider using atropine with neostigmine to reverse preterm infants or failure to thrive infants.

Term
What is great for mild pain or as an adjunct with opioids?
Definition
*Acetaminophen
Term
If acetaminophen is given prior to taking the pediatric patient to PACU, what MUST you do?
Definition
*Make recovery aware if it is given in the OR
Term
What can antiemetics cause in children?
Definition
*Sedation
Term
Why is absorption of local anesthetics more rapid in neonates?
Definition
*Cardiac output and regional tissue blood flow are higher and higher volume of distribution which also extends the elimination half life, less protein binding.
Term
In what children can Lidocaine produce toxic effects and the dose should be reduced by 50%.
Definition
*Children with right to left cardiac shuns because the normal first pass absorption into the lungs is bypassed.
Term
What is the safe dose of epinephrine in a test dose?
Definition

*Safe dose: 10mcg/mL

*in LA 5mcg/mL can be added to decrease peak concentration by 30-40%.  It also increases duration in infants and children 4-6 years old.

Term
Since a pediatric patient already has a high heart rate, what are you looking for to identify a positive test dose?
Definition
*Peaked T waves
Term
What is the first line of defense for bradycardia?  
Definition

*Epinephrine

*For tabletop setup:

<20kg dilute to 10mcg/mL

<5kg dilute to 1mcg/mL

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