Tongue

Position of Larynx

Epiglottis

Vocal Cords

Subglottis

Past knowledge thought tongue was large compared to oral cavity

Contribution of tongue to upper a/w obstruction actually minor

MAJORITY of obstruction d/t NASOPHARYNGEAL/EPIGLOTTIC collapse 

Higher, more cephalad (Level C3-C4)

Hyoid bone (C2-3)...up to age 2

Tongue closer to larynx= difficult visualization of larynx

Straight blade better 

Epiglottis axis angle with airway axis... more difficult to lift

stiff

Omega shaped, touch the soft palate (easy airway obstruction) 

Cords are angled more anteriorly

Anterior insertion of cords is lower than posterior insertion 

Functionally the narrowest portion of the larynx is the cricoid cartilage 

(Narrowest part for adults in cords) 

In children it is common to easily pass ETT through the vocal cords (glottic opening) but not through subglottic region 

Growth of the subglottis airway occurs rapidly during 1st 2 years

10-12 years cricoid and thyroid cartilages reach adult levels 

Angulation is then eliminated, narrow subglottic area resolved 

Begins during gestation week 4 

26-28 weeks gestation proliferation of the capillary network surrounding the terminal air spaces become sufficient for pulmonary gas exchange 

Produce surfactant that forms the alveolar lining

Reduces surface tension and stabalizes air spaces after air breathing

Appear at 24-26 weeks 

Fetal breathing movements detected as early as 11 weeks

First Inspiration- critical event from placental and pulmonary gas exchange

First Gasp- generates transpulmonary pressure 40-80 mmHg

Pulmonary blood flow sharply increases

Decrease in PVR and Increase SVR--> critical event immediate closure of foramen ovale

Reverse shunt through ductus arteriosus

HYPOXIA and ACIDOSIS= Increase PVR= R-L Shunt 

Inspiration is entirely a result of diaphragmatic descent**

Diaphragmatic Fatigue: in preterm infants--> apnea

Diaphragm has very little type I (slow twitch, high oxidative) muscle fibers 

Floppy, noncalcified cartilage, poorly developed musculature, noncalcified ribs, extend horizontally & move very little with inspiration 

Chest wall compliance decreases throughout childhood reflecting progressive calcification of the ribs 

FRC= 80

TLC= 160

PaO2= Infants: 60-90, 1 year: 80-100

VC= 120 

Neonates greater dependent on diaphragm 

When outward pull of chest= inward pull of lungs

Infants: end-expiratory volume> FRC

The infants chest wall more compliant, therefore, lung collapse not counterbalanced by chest wall rigidity 

Inspiratory muscles brake expiration impaired with GA--> tendency to develop atelectesis at regular TV 

In neonates is 2x that of adults d/t cartilage immaturity

B/c of this dynamic collapse of trachea may occur on inspiration and expiration

A greater inspiratory force sucks in the floppy airway and decreases airway diameter---> increases work of breathing

Chest wall highly compliant, ribs provide little support for lungs

Negative intrathoracic pressure poorly maintained

Function airway closure with each breath

Atelectesis develops rapidly 

PaO2 act on peripheral chemoreceptors in carotids and aorta

PaCo2 act on central chemoreceptors

Infants respond to increase PaCo2 NOT potentiated by hypoxia

Hypoxia may depress the hypercapnia ventilator response 

up to 1 week full term

High FiO2 concentrations DEPRESS respiratios

Low FiO2 concentrations STIMULATE respirations...BUT not sustained...eventually ventilatory depression occurs 

Infants are obligate nose breathers 

Obstruction of the nares can cause asphyxia

Immature coordination b/w resp efforts & motor & sensory inputs

3-5 months can coordinate resp & oral function--> larynx enlarges and moves down---> cervical spine lengthens 

O2 consumption in infant= 4-6 ml/kg/min

Greater O2 consumption= increased resp frequency

(greater metabolic demand)

Bronchiole and small airways 

Adults- nasal passages 60%

In infants the small diameter of bronchioles and very compliant chest wall results in less support to maintain NEGATIVE intrathoracic pressure 

means

Functional airway closure with every breath 

Small- airway resistance accounts for most of the work of breathing *** 

Affects 6 million children in the US

Hx Wheezing= Increased perioperative bronchospasm risk

Establish severity and control of asthma pre-op

Severe but well-controled vs mild but poorly controlled

Frequency and control of symptoms

Limitation of effort tolerance

Night awakenings

Medication use

***ER Department Admit***

Hospitalizations

Ventilation Support 

Children should continue regular medications

Consider B-Agonist inhaler before or after induction to prevent airway resistance after trachel intubation

Consider ketamine/propofol

NO DES

Deepen Anesthesia

Increase FiO2

Decrease PEEP

Increase expiratory time

Inhaler 

Lung disease is main morbidity

Malnutrition is common problem

Commonly anesthetize for ENT procedures d/t chronic sinus problems 

Prescence of URI

Snoring or Noisy Breathing

Croupy cough= subglottic stenosis

Inspiratory stridor?

History of Congential syndrome?

Baseline O2 saturation of room air?

Global Appearance

Appropraitely sized mask should sit on the bridge of the nose and extend to the mandible

Most common error: compressing submental trainagle with fingers, partialy occluding the airway

Keep mouth opend to not obstruct a/w

Hand on reservior bag at all times

Have one size larger and one size smaller than needed 

Tip of airway should end just cephalad to the angle of the mandible 

Use tongue depressor 

Should not be used as a bite block in children between 5 and 10 years of age with loose decidious teeth

Responsible for 55% of anesthesia- related dental complications

Bite blocks in long cases may cause necrosis of the tongue, uvular edema, or lip damage 

Tolerated in the lightly anesthetized child better than an oral a/w

Careful with hypertrophied adenoid and tonsils 

Large occiput of the infant provide natural neck flexion

Head extension aligns the oral, phayrnx, and tracha axes

> 6 years= sniffing 

3.0 uncuffed

3.0-3.5 cuffed 

3.5-4 uncuffed

3.0-4.0 cuffed 

4.0-5.0 uncuffed

3.5-4.5 cuffed 

Uncuffed= (Age +16)/4

Cuffed= (Age /40 +3 

Always have .5 greater and less than the anticipated size available

Leak shoud be 20-25 mmHg

Short term leak can be as high as 35 mmHg

If no leak---> .05 mm ETT smaller

Leak prevent tracheal mucosal damage

Less laryngoscopies

Decreased risk of aspiration

Accurate control of PCO2

Reduced use of anesthetic agents

No difference in post-extubation croup 

Variability in outer diameter b/c of differences in chuff shape and size

Use 0.5 size smaller if using cuffed tube

High volume/ low-pressure cuff 

more distal cuff 

ETT Depth 

Up to 1 year old 

5-9 cm 

(easy to remeber 10 cm)

ETT Depth 

1 year old 

ETT Tube 

2 year old 

ETT Depth 

> 2 years old 

Age/2 + 12

ID of ETT x 3

(weight in kg/5 + 12)

Observe for chest symmetry of expansion

Auscultate in axilla & apices (chest wall)

Reconfirm after positioning

increased a/w pressures 

desaturation

asymmetrical chest wall movement 

Increased risk with ETT with an OD too large, duration of surgery greater than 1 hours, traumatic intubation, age 1-4, repeated attempts.

Treat with nebulized epinephrine and decadron 

Prolonged intubation resulting in ischemic injury secondary to lateral wall pressure from ETT

edema, necrosis, and ulcerations in mucosa

Usually treated by surgical approach to removal of tissue 

Light premedication

Maintain spontaneous respirations 

Stylet for acute angle vocal cords 

Can accomadate a 1 kg baby

Sizes 0-4 

Stylet necessary for sucessful intubation

Sweeping tongue to left unnecessary

Anesthetic depth can be inferred from the rate and pattern of respiration

Airway obstruction can be detected by chest wall retractions or "seesaw" paradoxical motion

Skin and mucous membranes confirm adequate oxygenation, a pulse oximeter reading can significantly lag behind other indices of hypoxemia 

Capillary refill provides valuable information about the intravascular volume and cardiac output 

Cool, mottled, poorly perfused extremities should be examined closely for additional evidence of hypovolemia or reduced cardiac output even if the systemic arterial pressure remains normal 

Progression of this mottled appearance onto the trunk indicates extreme vasoconstriction that may herald iminent cardiovascular collapse 

Precordial stethoscope is useful during all phases of general anesthesia, as well as during transport of the child between hospital locations

Allows immediate detection of changes in the rate and character of heart and breath sounds

Gives the first warning of a physiologic alteration

Crisp heart tones are produced by the flow of blood through a briskly contracting heart. Myocardial depression initially results in a muffled and then in a distant quality to the heart tones 

Reserved for intubated patients or when precordial violates the surgical field 

The proper method for accurate placement of the esophageal stethoscope is to listen while simultaneously advanding the device and placing it at the level where the heart and lung sounds are maximal 

In small infants, unintentional placement of the esophageal stethoscope into the stomach can easily occur 

During routine uncomplicated cases, measurement of BP should be perfromed every 3-5 mins while child is anesthetized

Determination that are too frequent can result in limb ischemia 

BP cuff is most commonly placed on the upper arm but can be placed on the forearm, thigh, or calf

Inconsistent correlation of measurements obtained between the upper and lower limbs 

Width of BP should cover approximately 2/3 of the total length of the upper arm

A cuff that is too small incompletely occludes the artery, resulting in the premature return of detectable flow and falsely increases the pressure measurement

Error can be as great as 30 mmHg

Newborns produce between 0.5 and 4 ml urine/kg per hr in the 1st 3 hr or life 

Urine flow, initially ranges from 15 to 60 ml/kg per day, reaches as much as 120 ml/kg per day by the end of the 1st week 

90% of neonates producing 0.5 to 5 ml/kg per hour 

Neonate who is < 1 week old, urine flow alone is NOT as sensitive index of changes in CO or intravascular 

Beyond neonatal period, a urine flow 0.5 to 1 ml/kg per hour usually indicates adequate renal perfusion and function 

The capnographic tracing of small infants is often characterized by the lack of an apparent alveolar plateau

Usually a result of a higher RR, excessive dead space in the breathing circuit, or an excessive leak around an uncuffed endotracheal tube 

Doesnt instantaneously reflect the arterial saturation of the degree of desaturation 

When the patient is breathing high concentrations of O2 and the blood is fully saturated, a substantial decrease in PaO2 can occur without a change in SaO2 

Detected desaturation in children 30 seconds earlier in probes placed centrally than in those placed on fingers . By the time the value indicated by a peripheral sensor had decreased 5%, the valve indicated on central sensor was 30% to 40% lower 

During inhaltion induction, pharyngeal reflexes (swallowing) are abolished whereas laryngeal reflexes remain intact

Secretions accumulate in the hypopharynx without swallowing and cause breath-holding resulting from central apnea, a closure of the glottis, or both

Positive pressure ventilation using a mask and bag instead of suctioning the pharyn would push secretions farther down into the larny, stimulate the superior laryngeal nerve, and trigger real laryngospasm 

Mask without premedicatio is generally used in infants younger than 10 to 12 months because this age group readily separates from the parents 

Mask induction most easily by holding the end of anesthesia circuit in a cupped hand over the infants face or holding just off surface of the face