Pediatric Lecture 2A Flashcards
Lung development continues into first decade of postnatal life: Begins \_\_\_\_\_\_\_\_ Bronchial tree\_\_\_\_\_\_\_\_\_\_ Terminal air sac\_\_\_\_\_\_\_\_\_\_ Capillary networks\_\_\_\_\_\_
4 wks gestation
16-17 wks (gestation)
24 wks
26-28 wks
Formation of alveoli @_________
Alveoli form through @_________
36 wks gestation
8-10 yrs
At birth, neonatal lungs have
__________ not alveoli
1/10th adult mature lungs
10-20 million terminal air sacs ; Alveoli
Saccules,
Brain removes what substance?
bicarbonate
Transition to extrauterine life (lungs) what happens
3 major changes in the lungs?
There is Rapid lung expansion
↑pulmonary Blood flow
Initiation of regular respiratory rhythm
- Interruption of umbilical Blood Flow initiates→
- Initial amniotic fluid removed by _______via_____
- Residual amniotic fluid in lungs drained via______When?
-continuous, rhythmic breathing
-lung via upper airways
lymphatic/pulmonary channels; in first days of life
Changes in ______,_____ and _____→leads to what?
PaO2, PaCO2, and pH; acute decrease in PVR and increase in pulm. Blood Flow
Comment on LA pressure and RA pressure, pressure gradient and foramen ovale.
Increase in ↑LA pressure +↓RA pressure reverses pressure gradient across the Foramen ovale which causes a functional closure of THIS LEFT TO RIGHT one way flap valve.
Explain Control of respiration: Breathing is controlled by (3 factors) ? (IIO)
what provides afferent signaling?P_UC
- Input from sensors
- integration by central control system
- output to effector muscles
Afferent signaling provided by
- Peripheral arterial + central brainstem chemoreceptors
- Upper airway +intrapulmonary receptors
- Chest wall + muscle mechanoreceptors
-
- Carotid bodies and Aortic bodies
- Carotid Greater role at sensing arterial chemical sensing of both PaO2 and pH
Central chemoreceptors responsive to __________and __________are thought to be located or near the ______________
Arterial CO2 tension and pH
Ventral surface medulla
Nose, pharynx, larynx contain what?
what can they cause?
pressure, chemical, temperature, and flow receptors
Can cause apnea, coughing, changes in ventilation
Pulmonary receptors in lung parenchyma
What kind of receptors are they ? aka_______
Where are they located?
What do they balance?
These receptors may be involved and Cause what reflex?
That reflex Prevents what?
Slowly adaption receptors (stretch receptors)
In airway smooth muscle
Balance of inspiration/expiration
Might cause Hering-Breuer reflex
Prevents overdistention of lungs via vagal stimulation/ and prevents COLLAPSE OF THE LUNGS
Rapidly adapting receptors located where ?
Triggered by ___________
such as _____________
Between airway epithelial
Triggered by noxious stimuli
Dust, smoke, histamine
Parenchymal receptors located __________
next _________
Juxtacapillary receptors
• Next to alveolar blood vessels
Parenchymal receptors respond to what? (3)
• Respond to hyperinflation, chemical stimuli in pulmn.
circ., interstitial congestion
Does not depress upper airway latency (medications)
Ketamine
Chest wall Receptors are
Located in?
Sense changes in
Also have
- Mechanoreceptors
- In muscle spindle endings and tendons of resp. muscles
- Sense change in length, tension, and movement
- Joint properioreceptors
Central integration of respiration by two centers
Brainstem (involuntary)
Cortical (voluntary)
Cerebral cortex
Influence?
Involve in ?
Influence or overrides involuntary rhythm generation
Emotion, arousal, pain, speech, etc
Possible resp. rhythm generators ________and th _______________, neural circuits in the _____________
are though to be the rhythm generators
What do those groups of neurons do?
Pre-Bötzinger complex and the retrotrapezoid
nucleus/parafacial respiratory group, neural circuits in the
ventrolateral medulla are thought to be the respiratory rhythm generators
- They fire in an oscillation patterns which is moderated by input from other resp. centers
Involuntary integration of sensory input occurs in various respiratory nuclei and neural complexes in the
pons and medulla that modify the
baseline pacemaker firing of resp. rhythm generators
Involuntary integration of sensory input
Effectors of ventilation (4)
Neural efferent pathways
Muscles of resp.
Bones/cartilage of chest wall + airway
Elastic connective tissue
Upper airway patency is maintained by 2 things:
connective tissue
contractions of pharyngeal dilator muscles
Diaphragm produces most______During ________
volume during normal, quiet breathing
Provide →additional neg. pressure → more tidal volume
Abdominal + intercostal muscles + accessory muscles
(sternocleidomastoid, neck muscles
Expiration is the
elastic recoil of lungs + thorax
Normally
- Inspiration = ______
- Expiration = _______
active
passive
Vigorous breathing/obstruction
Both active
Chest wall infants change in compliance?
↓ chest wall compliance
In Infants, the chest wall is more compliant therefore the __________Is not counterbalanced by _________
What breaks expiration?
_____>_____
What impairs that mechanism?
tendency of lung to collapse NOT counterbalanced by chest wall rigidity
Inspiratory muscles brake expiration
ERV > FRC
The braking mechanism is Impaired by anesthesia which can lead to airway closure and atelectasis
Component of assessment
Assess for_____,_____,_____ pathology
Consider
which can be Impacted by
History, physical exam, evaluation of vital signs
Airway, musculoskeletal, neurologic
gas exchange
cardiac, hepatic, renal, or hematologic diseases
For pediatrics most important
O2 Saturation
Heart rate
Risk factors for airway Issues
- resp. infection within 2 weeks
- wheezing during exercise
- > 3 wheezing episodes within 12 mo, nocturnal dry cough, eczema
- family Hx asthma, rhinitis (runny nose)
- Exposure to tobacco smoke
Establish ______and ______of URI
Precipitating factors of _______frequency, severity and ______Factors
timeframe, freq., severity
Antibiotics?
wheezing, frequency, severity, relieving factors
For Chronic pulm. Dz =
assess what causes acute exacerbations
In young infants, figure out:
Gestational age at birth, current postconceptual age,
neonatal resp. difficulties, NICU/prolonged
intubation
Premies at risk for
R/T
apneic episodes
subglottic stenosis,
tracheomalacia (Weak cartilage)
prolonged intubation
For gross assessment
Inspect from a distance
Get baseline RR, SpO2, look for signs of accessory
respiratory muscle use (resp. distress)
Weight important because
Chronic pulm. Dz →
Severe obesity →
malnourished, underweight, growth retardation
obstruction, sleep apnea
Eczema + atopy (↑immune system) =
hyperreactive airway
Auscultation
Tests:
Wheezes, rales, fine/coarse crepitus, altered breath sounds, cardiac murmurs
chest imagine, Hct, ABG, PFT, sleep study
PFTs include
________,________, _________ . done to find __________________
What does it measure about dysfunction ?
Nature or dysfunction as either?
dynamic studies, measurement of static lung
volumes, diffusing capacity
Finds mechanical resp. dysfunctions
Quantifies dysfunction Defines nature of dysfunction Obstructive, restrictive, mixed
Dynamic studies
Spirometry
What is FEV/ FVC
Measures volume of air inspired and expired
Forced exhalation after maximal inhalation = forced vital
capacity (FVC)
Fraction of volume exhaled in the first second = forced
expiratory volume (FEV1)
Dynamic studies include
Spirometry
Flow volume loops
Peak expiratory flow
Obstructive PFT Obstruction =
decreased velocity of flow through airways
Normally should be able to exhale
more than
80% of FVC in 1 second
Normal FEV1/FVC =
0.8 or 80%
If exhalation over first second divided by total FVC is less than _______=
< 80 % =airway obstruction
Restrictive PFTs
Decreased__________ Both FEV1 and FVC _______
lung volume ↓ equally
Diagnosis of PFTs
FVC < 80% of normal
Normal or increased FEV1/FVC
Loss of lung tissue or inability to expand
Obstructive = more common in children is
Other examples
Asthma
Airway lesions, congenital subglottic webs, vocal cord dysfunction
Improvement in FEV1 of ____% is considered a response
12%; positive
Mixed problems with FEV, FVC 3 conditions
Cystic fibrosis
sickle cell disease
bronchopulmonary dysplasia
Restrictive
there is Limitations of_______ for example in _____,_____ and _______
chest wall movement
Deformities, scoliosis, pleural effusions
Restrictive: Space-occupying intrathoracic lesions
Large bullae or congenital cysts
Restrictive :Alveolar filling defects Examples
Pneumonia
Other use of PFTs
Differentiate fixed from variable airway obstruction
Localize obstruction above or below thoracic inlet
Fixed central airway obstruction
Tumor, stenosis
Obstructs both inspiration and expiration
Pancake flow-volume loop
Other variable obstructions?
Affect ______
During Inhalation = Chest ______ and airway are_______
What obstructs inhalation?
During exhalation = Chest _______, intrathoracic airway __________
What obtructs exhalation?
Variable obstructions Only affects one part of vent. Cycle Inhalation = chest expands and airways are drawn open Variable extrathoracic lesions obstruct inhalation Exhalation = chest collapses, intrathoracic airways close Variable intrathoracic lesions obstruct exhalation
Upper Respiratory Infection
Viral vs. bacterial?
Viral
Short-lived, self-limiting
↑airway sensitivity/reactivity/secretions for several weeks
severe coughing, and breath holding
What can a respiratory infection affect?
Can decrease FVC, FEV1, peak expiratory flow, and diffusion capacity
URI potential MOA
mucosal invasion, chemical mediators, altered
neurogenic reflexes
↑ laryngospasm, bronchospasm, arterial hemoglobin desaturation,
Runny nose with no fever kids—>
Ok to proceed
Elective surgery postponed if more severe symptoms
present: (3)
in between consider?
Mucopurulent secretions, lower respiratory tract signs
(wheezing), pyrexia >100.4°F (38°C), ∆ behavior/activity
In between?
Consider comorbidities, type of surgery/anesthetic,
contamination risk factor, ability to admit postoperatively
Proceed c/general anesthesia what to do?
Deep extubation ?
Depth of anesthesia must be adequate for airway
manipulation
Incidence of desaturation higher in awake children
Only 2 times to extubate
DEEPLY SEDATED
WIDE AWAKE
AVOID _______ and _______if possible because
airway stimulation Avoid ETT if possible
↑complications esp. young children
most effective, lest harmful way to provide anesthesia
Face mask
Facemask =
smallest airway complications
LMA could be a good intermediate
For URI Postpone elective cases
2-4 weeks
Wait that long for URI because it Allows for balancing of:
Time to ↓airway reactivity, periop. resp. risk, need to
perform surgery
Propofol vs sevo for laryngospasms
Propofol causes less laryngospasms than sevoflurane
What is LTA
LTA ( Laryngeal tracheal anesthesia ) insert, put lidocaine than remove and put ETT
No evidence to support LTA< but what does help?
Lubing LMA with lidocaine jelly, nasal vasoconstrictors
to reduce secretions
3 Lower respiratory diseases:
Asthma
Cystic fibrosis
Sickle Cell disease
Chronic disorder characterized by variable/recurring symptoms, ______, ______ and ________
Associated with____________ hypersensitivity
airway obstruction, inflammation, and hyperresponsiveness immunoglobulin E (IgE)-mediated hypersensitivity
Rare perioperative complications of asthma
1.Anaphylaxis
2. adrenal crisis
3. ventilatory barotrauma (pneumothorax or
pneumomediastinum)
Presentation ASTHMA:
wheezing, chest tightness or discomfort, persistent dry cough, and dyspnea on exertion
Signs of Severe resp. distress:
chest wall retraction, use of accessory muscles, prolonged expiration, pneumothorax, and progression to respiratory failure and death
Problems with asthma
Permanent airway changes = airway remodeling = nonresponsive to therapy
Problems with DIAGNOSIS of asthma
Coughing, wheezing, and bronchospasm are NOT exclusive to asthma = hard to diagnose
Asthma involves interaction of
host factors (genetics) and environmental exposures (smoking) which occur during an important time in immune system development
Chronic cough =_______
not required to diagnose asthma_______
most common manifestation of asthma in children
Wheezing
Acute vs Chronic airway
know difference
Potential perioperative complications for
Assess for
Bronchospasm, pneumonia, pneumothorax, death
Assess severity and control before surgery
Note presence of nocturnal dry cough, > 3 wheezing episodes in past 12 mo, Hx eczema
Treatments of asthma
- Albuterol
- ICS
- Increased ICS, manipulate mixture of SABA and ICS, and Also LABA, and theophylline.
For asthma , do we discontinue meds preop
NO
KETAMINE and ASTHMA
Ketamine IV induction agent of choice Bronchodilation!
Desflurane and ASTHMA →
↑risk of bronchospasm Avoid in asthmatics
Surgical stimulation can trigger
bronchospasm if not deep enough
Indication of Intraoperative bronchospasm
Polyphonic expiratory wheezing
Prolonged expiration
* Increased PEAK airway pressures (MOST IMPORTANT)
Expiration with increased respiratory effort
Slow upslope ETCO2 waveform
↑ETCO2
↓O2
Most important indication of Intraoperative bronchospasm?
increased PEAK AIRWAY PRESSURE
Treating intraoperative bronchospasm
_____Anesthesia, FiO2, PEEp, expiratory time
which does what?
Remove triggering stimulus if possible Deepen anesthesia ↑FiO2 ↓PEEP (Remove if able) ↑expiratory time Minimizes alveolar trapping
Meds to treat intraoperative bronchospasm
steroids?
Inhaled β-agonists 4-8 puffs More bronchodilation c/coadministration of ipratropium Corticosteroids Chronic use = adrenal crisis
I: E ratio should be appropriate
Expiratory 2 seconds (best alveoli exchange)
Are you able to put albuterol in anesthesia circuit
yes
_____________preferred over tracheal administration
Dose_______ may be repeated, followed by ________
- IV salbutamol (albuterol) (because patient is not breathing well so IV route is better)
- 10 mcg/kg May be repeated, followed by 5 -10 mcg/kg per minute for first hour until improvement
Epinephrine is an effective__________ (least favored)
bronchodilator
Dose: 0.05-0.5 mcg/kg/min
Status asthmaticus
Beware of _________ and
Signs of ___________
Other signs include
Beware of drowsy, silent child with quiet chest Imminent respiratory arrest Other signs: paradoxical thoracoabdominal movement bradycardia absence of pulsus paradoxus
Stats asthmaticus treatment
Requires emergent intubation
IV magnesium may be helpful
Bronchospasm compared to anaphylaxis differentiated from asthma by systemic signs
Angioedema, flushing, urticaria, CV collapse
Atopy-associated asthma =
↑risk of anaphylaxis c/NMB, antbx, latex
What not to do in an attempt to treat asthma
What NOT to do: Antibiotics Aggressive hydration (unless dehydrated ped) Mucolytics Chest physiotherap
Cystic fibrosis is a _________Disorder on chromosome
Autosomal recessive
7
Cystic Fibrosis is
Affect regulation of __________ in ________ surface
Impacts ______, _____, ______< _____
Affects regulation of chloride and other ion fluxes at epithelial surfaces
• Impacts sweat ducts, airways, pancreatic ducts, intestine, biliary tree, vas deferens
In cystic fibrosis there is __________concentration,
• Increased sweat chloride concentrations
viscous mucus production, lung Dz, intestinal obstruction, pancreatic insufficiency, biliary cirrhosis
• Multisystem disease
Pulmonary issues with cystic fibrosis
MOST major problem is (caps) , impaired _________ ____
Organisms involved
exacerbation
- MUCUS PLUGGLING, chronic infection, inflammation, epithelial injury, increased secretions, impaired ciliary clearance → infection
- Staph. Aureus, H. influenza
- Exacerbations of cough/sputum production
Pulsus Paradoxus
Change in pressure when they take breaths
Recurrent exacerbations
→progressive airway obstruction, bronchiectasis, emphysema, V/Q mismatching, hypoxemia Hemoptysis (growth of vessels with bronchiectasis)
Bronchial reactivity/airway resistance = common
Bullae formation =
pneumothorax
In Cystic Fibrosis , PFTs reflect ______pattern
PFTs reflect obstructive pattern (↑FRC, ↓FEV1/VC , ↓PEF)
Cystic Fibrosis end stage
cor pulmonale –> Cardiomegaly, fluid retention, hepatomegaly
More hemoglobin S than
A
Anesthesia complications for Cystic Fbrosis
Assess.
They have problem with___________
Assess severity, current state, progression, current
therapies, order advanced diagnostics if you suspect
major organ dysfunction
Problem with mechanical ventilation
Breathing in non-warmed, un-moisturized air
For rate of O2, considered high flow
4L high flow
Anesthesia complications Other lower structures have to expend energy warming
Less effectively, more likely to dehydrate, mucus gets thicker
Inhaled anesthetics directly impairs (3)
mucociliar escalator
blunts cough response
decreases ventilatory
Anesthesia consideration: Nebulized saline treatment up until surgery HME (Keep moisture in the circuit ) Clear secretions Can increase \_\_\_\_\_\_\_\_\_\_\_ Extubate after\_\_\_\_\_\_\_\_\_ Sitting up 30-40°
as needed but don’t over do it
- fully reversing NMB
airway resistance
Postop for Cystic Fibrosis :
continue humidification, initiate physiotherapy PRN,
careful titration of narcotics, early mobilization
Sickel Cell disease is
Mutation @
Gene codes_______ instead of______
Inherited hemoglobinopathy
chromosome 11
hgb S; hgb A
Sickle cells characterized by
Characterized:
Acute episodes of pain, acute and chronic pulmonary disease, hemorrhagic and occlusive stroke, renal
insufficiency, and splenic infarction,
Mean life expectancy of sickle cell patients
shortened to just over 3 decades
Acute chest syndrome (ACS)
- Lung damage Diagnosis: chest infiltrate c/ chest pain, fever 101.3°F (38.5°C), tachypnea, wheezing, cough
Etiologies: infection, fat embolism after bone marrow infarction, pulmonary infarction, and surgical
procedures
Associated with younger pts, ↓ body temp, and greater blood loss
due to SCD
Diagnosis:
chest infiltrate c/ chest pain, fever 101.3°F (38.5°C), tachypnea, wheezing, cough
Etiologies of SCD
Associated with younger pts, ↓ body temp, and greater blood loss
infection, fat embolism after bone marrow infarction, pulmonary infarction, and surgical
procedures
Sickle cell do not let these patients get
COLD
Chronic = sickle cell lung disease Manifestations:
Obstructive pattern in children, restrictive in adults
Later stages: Both VC + TLC↓, gas diffusion impaired,
pulmonary fibrosis, pulmonary artery hypertension, right
-sided cardiomyopathy, and progressive hypoxemia
Get a CXR and look for
Decreased distal pulmonary vascularity
Diffuse interstitial (eventually pulmonary) fibrosis
Cardiomegaly
Perioperative management Cystic Fibrosis
Transfusion to
Goal:__________
↑risk
High risk: children c/risk or hx of stroke
Risk factors: low hgb, HTN, male gender
Commonly develop postop atelectasis
Fine line with pain medicine
Too much = atelectasis, not enough =
PRBC transfusion to decrease risk of periop ACS
correct anemia to Hct 30%
-hypoventilation…atelectasis
Anesthesia goals for SCD
regional when possible, nonopioid
analgesics, incentive spirometry, early mobilization,
good pulmonary toilet
Support gas exchange: supplement O2, positive
pressure, bronchodilators, correction of anemia
Key points: neonates alveoli ______and _______
Fewer and smaller
Key points: Neonates lung compliance and chest wall?
Fewer and smaller alveoli reduce lung compliance
CHEST WALL is very compliant
Key points: Because there is _______in lung compliance and _______in chest wall compliance, those two things promote 2 things
Chest wall collapse during inspiration
Low residual volume at expiration
Key Points : The low residual volume, FRC is __________which limit _______Reserve when there is ______ such as when there is an intubation attempt, therefore, it predisposes neonates to _________and _________
Lower; O2 reserve; Apnea; Atelectasis and hypoxemia
Key Points: These features make them NOSE BREATHERS up until what age____? Nwrrowest part ?
Larynx : anterior and cephaload
Epiglottis: longer
Trachea and neck: shorter
Cricoid
Key Points: Cardiac SV is _________ because of ______and noncompliant _______ventricle in neonates and infant.Therefore ______is very sensitive to changes in HR
fixed; immature ; left
Key points: Why do pediatric are at risk for greater heat loss to environment?
Thin skin, low fat, greater surface area in relation to weight
Key points: Hypothermia put the pediatric patient at risk for
Delayed awakening
Arrhythmias
Respiratory depresswion
Increased PVR.
Neonates, infants and children have
GREATER ALVEOLAR VENTILATION
REDUCED FRC
Key points: Because neonates and kids have greater ventilation (MV) to FRC ration what does it lead to ___________ combined with greater ____________ there is ________ _______
Rapid increase in alveolar anesthetic concentration; Greater blood flow to the brain ; Speed inhalation induction
Key points: Viral infection
Viral infection within 2-4 weeks before anesthesia/ ETT appears to put at increased risk for pulmonary complications including, wheezing, laryngospasm, HYPOXEMIA, and ATELECTASIS
How can you avoid laryngospasm in the pediatric patient?
Extubating while awake
OR
Extubating while deeply sedated
Children and succynylcholine
At higher risk for adverse effects related to SUCC.
Pediatric Scoliosis due to ______ ______ are predisposed to
Muscular dystrophy: arrhythmia, MH , untoward effect of succinylcholine.
Children not pre-medicated with atropine may experience __________with succinylcholine
Profound Bradycardia
