Week 7: Airway, Preoperative, Blood conservation

Question 1

Blood Conservation Strategies

Risks of blood transfusion require thoughtful consideration prior to initiating transfusion therapy.

Strategies include:

Answer 1

• Erythropoietin administration,
• Autologous blood donation,
• Cell salvage intraoperatively,
• Controlled hypotension, and
• Normovolemic hemodilution.

Question 2

Blood Conservation Strategies- autologous blood

1. Autologous blood is usually reserved for ________ as _________ are not able to replenish the donated RBCs as effectively as adults.
2. Directed donor blood is an option. Although there a lack of evidence that this is safer than blood products donated from the general population.

• Blood products obtained from a blood relative should be ________ to eliminate the possibility of ________.

Answer 2

1. Teenagers, younger children
2. irradiated; GVHD

Graft-versus-host disease (GvHD)

Question 3

Blood Conservation Strategies- cell saver

• Useful to minimize allogenic blood transfusion in __________.
• The recovered and washed blood will have a Hct of ___-_____.
• Minimizes the risks of _____ and ________ risk if the reinfusion is administered in the operating room.

Answer 3

• spine surgery
• 50-60%
• infection and immunologic

Question 4

Blood Conservation Strategies- cell saver

Cons

Answer 4

• Pediatric sized equipment is ideal and may be challenging to obtain.
• Not appropriate if the surgical field is contaminated or if clotting agents, antibiotics or other foreign materials have been used on the surgical field

Question 5

Blood Conservation Strategies- controlled hypotension

• Used to reduce intraoperative blood loss in an appropriate patient population.
• Techniques vary depending upon the nature of the blood loss (acute vs slow, chronic).
• The trend is to aim for a MAP of _____-_____mmHg.
• Agents include:

Answer 5

• 65-70

• Inhalational anesthetics
• Beta blockade (limited application)
• Sodium nitroprusside
• Nitroglycerin
• Remifentanil

Question 6

Blood Conservation Strategies-controlled hypotension

• Maintain _________
• UOP should be _______
• If the head is the surgical site, calibrate the transducer at the head level in order to obtain adequate cerebral perfusion pressure.
• Obtain frequent ABGs to monitor EBL, electrolytes, glucose, and medication toxicities

Answer 6

• normovolemia
• 0.5-1ml/kg/hr

Question 7

Blood Conservation Strategies- normovolemic hemodilution

• Most common method is to remove blood at the beginning of surgery while replacing the volume with ______ or ________ and then returning blood at the end of the procedure when _______ is achieved.
• A hematocrit goal of ______% is generally well tolerated in a healthy child for a case that is not _______.
• ____________ is a key concept.

Answer 7

• crystalloid or albumin; hemostasis
• 20; prone
• Normovolemia

Question 8

Emergence Delerium

• Most often seen in the ________ population
• Children with preoperative ________ and/or a history of ___________ are more likely to develop emergence delirium.

• Anesthetic techniques to minimize likelihood of emergence delirium include:

Answer 8

• preschool
• anxiety; temper tantrums

• TIVA
• Propofol bolus at end of surgery
• Regional anesthesia
• Dexmedetomidine
• Fentanyl
• Ketorolac

Question 9

Article

Cardiac arrest and brain death in pediatric patients are still mainly caused by:

Most common cause:

other etiologies

Answer 9

airway problems (27%)

Laryngospasm (respiratory-related)

• airway obstruction
• difficult intubation
• esophageal intubation
• aspiration

Question 10

Article

1. Consider bradycardia to be caused by ______ until proven otherwise.
2. Hypoxia in an adult or older child usually triggers a _________ response, producing a _________ that improves oxygen delivery. ____________ is a late and very dangerous sign of imminent cardiovascular collapse.
3. In contrast, ____________ in babies and young children may be the first sign of hypoxia—not the last. The small child’s immature nervous system has a better developed ____________ nervous system
4. As a result, hypoxia triggers a ____________ response and ___________.

Answer 10

1. hypoxia
2. sympathetic; tachycardia; Bradycardia
3. bradycardia, parasympathetic
4. vagal; slows the heart

Question 11

Article

Infants and small children have a cardiac output that is _________ dependant. __________ significantly lowers cardiac output and oxygen delivery; hypoxia and hypercarbia worsen. Acidosis develops, further depressing the myocardium.

Answer 11

rate- dependent;

hypoxia

Question 12

Article: Children Are Easily Oversedated

1. Nerve ____________ is incomplete and the _________ is poorly developed at birth.
2. Central nervous system immaturity, combined with relative lack of exposure to drugs, can cause _______ and ______ even in older children.

Answer 12

1. myelination; blood–brain barrier
2. respiratory depression and apnea

Question 13

Article

• Altered control of ventilation, with _______ and __________, can be seen up to about 60 weeks post-conceptual age.
• Young infants, especially if they have a history of prematurity are at high risk for apnea. Hospital will observe expremature infants less than 60 gestational weeks overnight following GA.

Answer 13

• Periodic breathing and apneas

Question 14

Article

Immature behavior increases the risk for hypoxia in children in the following ways:

Answer 14

• Stress and physical struggling increase metanolic rate and O2 consumption.
• Crying increases sescretions, airway irritability, and airway edema
• Incease WOB due to physical struggling
• Active URI or wheezing increases WOB too

If the child has aspirated a peanut or has croup, panic and crying will make it worse.

Question 15

Article

Scared children cry which causes:

Answer 15

Question 16

Article

Pediatric anatomy differs in 4 main ways

Answer 16

• size
• composition
• position
• shape

Question 17

Article

• The infant’s large head relative to body size, rounded occiput, large tongue, and larynx positioned higher in the neck all predispose to ____________ if the head flexes forward or the child loses consciousness
• The laryngeal and tracheal cartilages are soft and easy to compress.
• Infants have suffocated while being held in an extreme flexed postition during ________.

Answer 17

obstruction;
lumbar puncture

Question 18

Article

The larynx itself has a different shape.
- The airway in infants and children is _______ at the top, above the glottis, and narrows below the _________ in the subglottic area.
- This _________ shape predisposes the child to a greater risk for airway obstruction from processes causing subglottic edema, such as croup or intubation trauma
- The larynx and trachea are so small that minimal swelling can cause tracheal obstruction.

Answer 18

• wider; larynx
• funnel

Question 19

Article

If an infant with a 4-mm trachea develops 1-mm circumferential edema, there is a _______% decrease in area, with an associated _______ times increase in resistance.

Answer 19

75; 16

Question 20

Table 1 anatomy and risks

Narrow nostrils, newborn is obligate nose breather

Answer 20

• Nasal obstruction in newborn causes airway obstruction and respiratory distress.
• Choanal atresia can cause cyanosis when baby feeds, which resolves when baby cries

Question 21

Table 1 anatomy and risks

Occiput is large and round, compared with flatter adult skull

Answer 21

• When supine, occiput flexes head forward, potentially obstructing airway

you should place a small rolled towel under the shoulders in children younger than 2 years to open the airway

As the child reaches 2 years of age, the occiput gradually becomes less prominent but is still rounded. Keeping the head in a more neutral position is helpful at this age. At some point in the older child, placing a roll under the child’s head, as you would with an adult, improves the airway

Question 22

Table 1 anatomy and risks

Tongue large relative to mouth,
filling the oropharynx

Answer 22

• Tongue easily obstructs larynx if baby loses consciousness

Question 23

Table 1 anatomy and risks

Laryngeal and tracheal cartilage soft and easily compressed

Answer 23

• Excessive flexion or extension of the head, as well as external pressure on the larynx can obstruct airway

Question 24

Table 1 anatomy and risks

Larynx higher in neck:
near c2, c3

vs. adult c4, c5

Answer 24

with larynx higher, the tongue and soft tissue can easily obstruct the larynx

Question 25

Table 1 anatomy and risks

Cricoid ring is narrower than glottic opening, reverse in adult

laryngeal and tracheal diameter is very narrow

Answer 25

• Narrow cricoid creates a funnel shaoped larynx
• palces child at risk for obstruction from subglottic edema such as croup

minimal edema can cause significant obstruction

Question 26

Table 1 anatomy and risks

Neck is short

Answer 26

• Infant’s chin rest on the chest, reaching the second rib
• hyoid overlaps thyroid cartilage
• identification of laryngeal landmarks for emergency percutaneous airway placement is difficult

Question 27

Table 1 anatomy and risks

Trachea is short

Answer 27

• accidental extubation and mainstem intubation occur

Question 28

Table 1 anatomy and risks

Adenoids and tonsils fill posterior pharynx

baby teeth become loose

Answer 28

• hypertrophic tonsild and adenoids can cause OSA and make manual ventilation difficult

• accidental aspiration of loose teeth during airway management

Question 29

Article: Oral Airways Must Be the Correct Size

1. the correct-sized oral airway places the flange immediatediately outside the teeth or gums and positions the tip near the __________.
2. airway that is too small:
3. airway too large:

Answer 29

1. Vallecula
2. Places the tip in the middles of the tongue, bunching the tissue and worsening obstruction. It can obstruct lingual vein and cause tongue swelling
3. Extends from the mouth and prevents sealing the mask over the face. it can fold the epiglottis down over the glottic opening and worsen obstruction.

Question 30

Article: Nasal airway

1. can cause nosebleeds, especially in ____ to ____ year old children with __________.

Answer 30

1. 3-6; hypertrophied adenoids

They can become plugges adenoidal tissue, which can be aspirated.

Question 31

Article

1. The infant metabolic rate is roughly ______ the adult rate.
2. Full-term infants are born with ______ million to ______ million alveoli, about 10% of the 200 million to 500 million found in the adult—giving them about ______ times less area for gas exchange.
3. Regardless of age, a normal resting tidal volume (TV) is about:

Answer 31

• double
• 20 - 50; 26
• 8 mL/kg of lean body weight

Question 32

Article

1. FRC in an adult is about _______ mL/kg and is about _______ mL/kg in the infant. With a 75% smaller oxygen tank, the infant can’t hold his breath as long as an adult.
2. Dead space is also ________ in the infant (_____compared with _____ mL/kg in the adult). A larger dead space means less of the ________ is available to ventilate alveoli and more of each breath is wasted.

Answer 32

1. 70; 18
2. higher; (3 vs. 2), TV

The infant or toddler must have a higher respiratory rate and heart rate to compensate for smaller TVs, larger dead space, higher oxygen consumption, and higher carbon dioxide production

The smaller TVs of an infant and a toddler also increase the risk for barotrauma when they are exposed to large TVs or high inflation pressures.

Question 33

Article: An Infant’s Chest Wall Increases Work of Breathing

• The pediatric chest wall is mechanically less efficient and limits potential lung expansion. Babies “belly breathe.” To take a deep breath, the infant’s chest can only expand a little because of the more _________ angles of the rib cage.

Answer 33

• horizontal

The abdomen therefore expands a lot as the diaphragm descends, pushing abdominal contents down and out of the way.

Question 34

Article

• The infant’s chest wall is also ______ compliant than an adult’s, with an elastic recoil close to _______ because of the lack of rib cage ossification.
• When the infant takes a breath against resistance, such as with airway obstruction or poor pulmonary compliance from pneumonia, the chest wall actually moves ______ as the belly moves ________.
• The inward movement of the chest wall decreases the amount of air that enters. A _______ chest wall motion is very common in children who have even partial airway obstruction.
• Because chest wall structure and belly breathing limit the ability to increase TV, the infant must rely on increases in__________ to compensate for respiratory distress

Answer 34

• more; zero
• inward, outward
• rocking
• respiratory rate

Question 35

Anatomic dead space on a healthy infant vs. adolescent

Answer 35

• (3ml/kg) vs. (2ml/kg)

Question 36

Infants and toddler

Chest-wall more box-like
- Rib angles mechanically innefficient
- Limited lung expansion
- Limited TV increases
- Alveolar ventilation is ________ dependendent.

Answer 36

• respiratory

Question 37

T/F: It is easier, and safer, to deliver a 30-mL TV when using a 250-mL infant bag than a 1-L adult bag

Answer 37

T

Question 38

If you don’t see chest expand, the _______ is too small.

Answer 38

Tidal Volume

Question 39

A broselow tape is color-coded measuring tape that correlates the _______ of the child with the average ________ of such a child.

Answer 39

length; weight

Broselow Tape can be misleading. The tape gives the dosage of medications for each size child in milligrams. The problem is that we administer liquid medications in milliliters

Question 40

The anatomy of babies and toddlers often produces a slightly more anterior airway as follows:

The pediatric larynx is located higher in the neck than in an adult, making it harder to lift the epiglottis by pressing on the ____________ ligament.

The tongue is larger relative to the size of the mouth.

Babies in particular have short necks.

There is a smaller separation between the _______ and _______ cartilage

Answer 40

hyoepiglottic;

Hyoid and thyroid

Question 41

Uncuffed ETTs in infants and children younger than about ______ years because the smallest diameter of the younger child’s airway is the cricoid ring

Children older than ______ years need a cuff to seal the trachea, because by this age the triangular ____________ opening has become the smallest diameter.

Answer 41

8; 8

vocal cord

Cuffed tubes should be considered for critically ill children, or children undergoing certain surgical procedures where sealing the airway and allowing higher ventilation pressures may be needed.

Question 42

The optimally sized uncuffed ETT lets you ventilate while allowing a leak at about _____ to ______ cm H2O.

This pressure leak value minimizes the risk for ischemia from compression of the tracheal mucosa.

A leak at a _________ pressure makes controlled ventilation difficult and increases the risk for aspiration.

Answer 42

20 -25
lower

Question 43

1. The ear canal should be roughly level with the _________.
2. The pediatric _________ and ___________ incline anteriorly, an angle that can cause the ETT to catch on the anterior commissure during insertion
3. Stop and ventilate if intubation is taking longer than ____ - ______.

Answer 43

1. sternal notch
2. arytenoids; vocal cords
3. 30seconds - 1minute

Question 44

Depth at the lip (ATL) formula

• for children >2y/o
• for infants and children < 2 y/o

Answer 44

• (age in years/2) + 12
• Calculated uncuffed ETT interior diameter x 3

Question 45

Closure of the larynx occurs by four mechanisms

Answer 45

• Closure of the vocal cords, both by pulling them together and by tensing;
• Closure of the false vocal cords;
• Mounding of the paraglottic tissues (lower epiglottis, paraglottic fat, base of tongue) by elevation of the larynx; and
• Folding of the epiglottis over the glottic opening

Question 46

Measures to manage laryngospasm

Answer 46

• Consider postponement of elective surgery if the child has a significant upper respiratory infection or active wheezing.
• Never stimulate the airway in stage II anesthesia.
• Don’t extubate if the child is actively coughing. Time removal for quiet breathing when the cords will be open.
• Keep the airway clear of secretions.
• Consider a muscle relaxant during intubation of a high-risk child.

Question 47

How to recognize laryngospasm?

1. Laryngospasm can be obvious or subtle, but it always shows signs of _________.
2. Depending on severity, there may be very little chest or ventilation bag movement with spontaneous ventilation.
3. When laryngospasm is complete, no ventilation is possible.
4. Signs of airway obstruction include: ________, __________, and ___________.
5. There will be stridor if laryngospasm is partial; however, stridor won’t occur without some air movement

Answer 47

1. airway obstruction
2. Rib retraction, Tracheal tug, and Rocking breathing movements (chest falls and abdomen rises with inspiration).

Question 48

Break laryngospasm:

Answer 48

• First stop stimulating the vocal cords. Suction the airway. Sometimes simply removing the object that touched the vocal cords or the secretions is enough to break the spasm.
• Getting the patient out of stage II will break the spasm. This can be done by either deepening the anesthetic (with gas or intravenous agents) or allowing the patient to awaken to the point where the reflex stops itself (waiting usually not an option -hypoxia).
• Direct all efforts to delivering oxygen. Apply your ventilation mask tightly against the face, and provide a continuous positive pressure breath with your ventilation bag while performing a jaw thrust. The jaw thrust is important
• If laryngospasm is not breaking quickly with positive pressure alone. A small dose of a sedative drug, such as propofol, may be needed. This deepens the level of anesthesia and usually stops the spasm.
• If sedation doesn’t break it, then give a small dose (0.25-0.5 mg/kg IV) of a short-acting muscle relaxant, such as succinylcholine, to restore your ability to ventilate. If you don’t have IV access, then give this as an intramuscular dose (3-4 mg/kg IM)

Question 49

4 sizes of pediatric GVL:

GVL 0
GVL 1
GVL 2
GVL 2.5

Answer 49

GVL 0: <1.5 KG

GVL1: 1.5-3.6 KG

GVL 2: 4-20 KG

GVL 2.5: 10-28 KG

Question 50

• _______, ______, and_________ have been the leading causes of respiratory events resulting in cardiac arrest in healthy children.

Answer 50

laryngospasm, failure to ventilate and failure to intubate

Question 51

Signs of a difficult airway include

Answer 51

• Edema or bleeding in and around the oropharynx
• Congenital facial anomalies such as facial asymmetry
• Chin that is short or hypoplastic
• Limited opening of the mouth
• Limited range of motion of the neck
• Prominent overbite
• Very large tongue (macroglossia)
• Poor visibility of uvula
• Extreme obesity (often with a short neck and significant double chin)
• History of sleep apnea
• Larynx fixed to the midline by a tumor or scar
• Neck mass
• Vocal cord abnormalities
• Mucopolysaccharidoses

Question 52

The cricothyroid space is underdeveloped in young children. Percutaneous needle or surgical cricothyrotomies and tracheostomies carry a higher risk for trauma and failure. A ______________ in children younger than 8 years may be preferable.

Answer 52

• Rigid bronchoscopy

Question 53

Avoid manual bag-valve ventilation in a child with an aspirated foreign body until after you have attempted removing it. ___________ may push it farther down the airway, precipitating complete obstruction.

Allow the child to breathe spontaneously until deep enough under ___________ to perform laryngoscopy or bronchoscopy to remove the object.

Answer 53

Positive pressure
Inhalational anesthesia

As a last resort, if you have been unable to ventilate the patient, intubation can be used to both establish an airway as well as to push the object farther down the trachea and into a mainstem bronchus. This will allow at least partial ventilation and the foreign body can be removed later by bronchoscopy, once the crisis has passed. The risk is blocking the carina, but if you can’t ventilate at all, it may be a risk worth taking.

Question 54

With deep extubation, the ET tube is removed before __________ and before the ___________.

Answer 54

wake-up
return of upper airway reflexes.

Question 55

Deep extubation is considered when coughing during wake-up could be detrimental to the patient ex:

Answer 55

• intracranial or
• head and neck surgery

Question 56

T/F ‘Deep’ extubation does not guarantee that a patient won’t cough during wake-up, but it certainly reduces the risk.

Answer 56

True

Question 57

Which patient is not a candidate for deep extubation?

Answer 57

• a patient who required RSI for a “full stomach”
• severe GERD
• Difficult airway
• Obese patients
• Risk of aspiration pt

Question 58

Use at least _______ MAC of VA during deep extubation

Answer 58

1

There should be no response to suctioning of the oral cavity and hypopharynx. if there is pt. is too light

Question 59

For deep extubation the patient should have an established, more or less spontaneous resp pattern and rate .

A good approach is to select a pressure support mode and maintain peep without the pressure support, essentially delivering ________ during spontaneous breathing.

Answer 59

CPAP