Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Anesthesia and Perioperative Medicine > Airway Management > Flashcards

Airway Management Flashcards

1
Q

Airway anatomy

A
  • resistance to airflow through nasal passages accounts for approximately 2/3 of total airway resistance
  • pharyngeal airway extends from posterior aspect of the nose to cricoid cartilage
  • glottic opening (triangular space formed between the true vocal cords) is the narrowest segment of the laryngeal opening in adults
  • the glottic opening is the space through which one visualizes proper placement of the ETT
  • the trachea begins at the level of the thyroid cartilage, C6, and bifurcates into the right and left main bronchi at T4-T5 (approximately the sternal angle)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Methods of supporting airways

A
  1. non-definitive airway (patent airway)
    ■ jaw thrust/chin lift
    ■ oropharyngeal and nasopharyngeal airway
    ■ bag mask ventilation
    ■ LMA
  2. definitive airway (patent and protected airway)
    ■ ETT
    ■ surgical airway (cricothyrotomy or tracheostomy)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Bag and Mask advantages/indications

A

Basic
Non-invasive
Readily available

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Bag and Mask disadvantages/contraindications

A

Risk of aspiration if decreased LOC

Cannot ensure airway patency

Inability to deliver precise tidal volume

Operator fatigue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Bag and Mask other

A

Facilitate airway patency with jaw thrust and chin lift

Can use oropharyngeal/ nasopaharyngeal airway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Laryngeal Mask Airway (LMA) advantages/indications

A

Easy to insert

Less airway trauma/irritation than ETT

Frees up hands (vs. face mask)

Primarily used in spontaneously ventilating patient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Laryngeal Mask Airway (LMA) disadvantages/contraindications

A

Risk of gastric aspiration

PPV <20 cm H20 needed

Oropharyngeal/retropharyngeal pathology or foreign body

Does not protect against laryngospasm or gastric aspiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Laryngeal Mask Airway (LMA) sizing

A

Sizing by body weight (approx)
40-50 kg: 3
50-70 kg: 4
70-100 kg: 5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Endotracheal tube (ETT) advantages/indications

A

Indications for intubation (5Ps)

Patent airway

Protects against aspiration

Positive pressure ventilation

Pulmonary toilet (suction)

Pharmacologic administration

also hemodynamic instability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Endotracheal tube (ETT) disadvantages/contraindications

A

Insertion can be difficult

Muscle relaxant usually needed

Most invasive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Endotracheal tube (ETT) other

A

Auscultate to avoid endobronchial intubation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

ETT sizing

A

intubation Sizing (approx):

Male: 8.0-9.0 mm

Female: 7.0-8.0 mm Pediatric Uncuffed (>age 2) (age/4) + 4 mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Equipment required for intubation

A

MDSOLES

Monitors
Drugs
Suction
Oxygen source and self-inflating bag with oropharyngeal and nasopharyngeal airways
Laryngoscope
Endotracheal tubes (appropriate size and one size smaller)
Stylet, Syringe for tube cuff inflation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Medications that can be given through the ETT

A 
NAVEL 
Naloxone 
Atropine 
Ventolin 
Epinephrine 
Lidocaine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Preparing for ETT intubation

A
  • failed attempts at intubation can make further attempts more difficult due to tissue trauma
  • plan, prepare, and assess for potential difficulties (see Pre-Operative Assessment, A2)
  • ensure equipment is available and working (test ETT cuff, check laryngoscope light and suction, machine check)
  • pre-oxygenate/denitrogenate: patient breathes 100% O2 for 3-5 min or for 4-8 vital capacity breaths
  • may need to suction mouth and pharynx first
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Proper positioning for intubation

A

• align the three axes (mouth, pharynx, and larynx) to allow visualization from oral cavity to glottis
■ “sniffing position”: flexion of lower C-spine (C5 C6), bow head forward, and extension of upper C-spine at atlanto-occipital joint (C1), nose in the air
■ contraindicated in known/suspected C-spine fracture/instability

• laryngoscope tip placed in the epiglottic vallecula in order to visualize cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Tube insertion

A

• laryngoscopy and ETT insertion can incite a significant sympathetic response via stimulation of cranial nerves 9 and 10 due to a “foreign body reflex” in the trachea, including tachycardia, dysrhythmias, myocardial ischemia, increased BP, and coughing

• a malpositioned ETT is a potential hazard for the intubated patient
■ if too deep, may result in right endobronchial intubation, which is associated with left-sided atelectasis and right-sided tension pneumothorax
■ if too shallow, may lead to accidental extubation, vocal cord trauma, or laryngeal paralysis as a result of pressure injury by the ETT cuff

• the tip of ETT should be located at the midpoint of the trachea at least 2 cm above the carina and the proximal end of the cuff should be placed at least 2 cm below the vocal cords
■ approximately 20-23 cm mark at the right corner of the mouth for men and 19-21 cm for women

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Confirmation of tracheal placement of ett

A

• direct
■ visualization of ETT passing through cords
■ bronchoscopic visualization of ETT in trachea

• indirect
■ ETCO2 in exhaled gas measured by capnography – a mandatory method for confirming the ETT is in the airway
■ auscultate for equal breath sounds bilaterally and absent breath sounds over epigastrium
■ bilateral chest movement, condensation of water vapour in ETT visible during exhalation and no abdominal distention
■ refilling of reservoir bag during exhalation
■ CXR (rarely done): only confirms position of the tip of ETT and not that ETT is in the trachea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Esophageal intubation suspected when

A

■ ETCO2 zero or near zero on capnograph
■ abnormal sounds during assisted ventilation
■ impairment of chest excursion
■ hypoxia/cyanosis
■ presence of gastric contents in ETT
■ breath sounds heard when auscultating over epigastrium/LUQ
■ distention of stomach/epigastrium with ventilation

20
Q

Differential diagnosis of poor bilateral breath sounds after intubation

A

DOPE

Displaced ETT
Obstruction
Pneumothorax
Esophageal intubation

21
Q

Complications during laryngoscopy and intubation

A
  • dental damage
  • laceration (lips, gums, tongue, pharynx, vallecula, esophagus)
  • laryngeal trauma
  • esophageal or endobronchial intubation
  • accidental extubation
  • insufficient cuff inflation or cuff laceration: results in leaking and aspiration
  • laryngospasm
  • bronchospasm
22
Q

Predicting difficult intubation in apparantly normal patients

A

A combination of the Mallampati score and thyromental distance is the most accurate at predicting difficult intubation. The PLR (9.9) is supportive of the test as a good predictor of difficult intubation.

23
Q

What are important preventative measures for difficult airway

A

pre-op assessment

pre-oxygenation

24
Q

If difficulty airway expected consider what types of intubation

A

awake intubation

intubating with bronchocope, trachlight (lighted stylet), fibre optic laryngoscope, glidescope, etc

25
Q

If intubation is unsuccessful after induction

A
  1. CALL FOR HELP
  2. Ventilate with 100% o2 via bag and mask
  3. Consider returning to spontaneous ventilation and/or waking patient
26
Q

If bag and mask ventilation inadquate

A
  1. CALL FOR HELP
  2. Attempt ventilation with oral airway
  3. consider/attempt LMA
  4. emergency invasive airway access (e.g. rigid bronchoscope, cricothyrotomy, or tracheostomy)
27
Q

Cyanosis can be detected at

A

SaO2 <85%,

frank cyanosis at SaO2 = 67%

28
Q

What are low flow oxygen systems

A
  • provide O2 at flows between 0-10 L/min
  • acceptable if tidal volume 300-700 mL, respiratory rate (RR) <25, consistent ventilation pattern
  • dilution of oxygen with room air results in a decrease in FiO2
  • an increase in minute ventilation (tidal volume x RR) results in a decrease in FiO2

• e.g. nasal cannula (prongs)
■ well tolerated if flow rates <5-6 L/min; drying of nasal mucosa at higher flows
■ nasopharynx acts as an anatomic reservoir that collects O2
■ delivered oxygen concentration (FiO2) can be estimated by adding 4% for every additional litre of O2 delivered
■ provides FiO2 of 24-44% at O2 flow rates of 1-6 L/min

29
Q

What things shift the PaO2/SaO2 curve down

A

Increased pH

Decreased 2,3-BPG

Decreased temp

30
Q

What things shift the PaO2/SaO2 curve up

A

Decreased pH

Increased 2,3-BPG

Increased temp

31
Q

What are reservoir oxygen systems

A

• use a volume reservoir to accumulate oxygen during exhalation thus increasing the amount of oxygen available for the next breath

• simple face mask
■ covers patient’s nose and mouth and provides an additional reservoir beyond nasopharynx
■ fed by small bore O2 tubing at a rate of at least 6 L/min to ensure that exhaled CO2 is flushed through the exhalation ports and not rebreathed
■ provides FiO2 of 55% at O2 flow rates of 10 L/min

• non-rebreather mask
■ a reservoir bag and a series of one-way valves prevent expired gases from re-entering the bag
■ during the exhalation phase, the bag accumulates with oxygen
■ provides FiO2 of 80% at O2 flow rates of 10-15 L/min

32
Q

Composition of air

A
  1. 1% nitrogen
  2. 9% oxygen
  3. 9% argon
  4. 04% carbon dioxide
33
Q

What are high flow oxygen systems

A
  • generate flows of up to 50-60 L/min meet/exceed patient’s inspiratory flow requirement
  • deliver consistent and predictable concentration of O2

• Venturi mask
■ delivers specific FiO2 by varying the size of air entrapment
■ oxygen concentration determined by mask’s port and NOT the wall flow rate
■ enables control of gas humidity
■ FiO2 ranges from 24-50%

34
Q

Ventilation and muscle relaxants

A
  • ventilation is maintained with PPV in patients given muscle relaxants
  • assisted or controlled ventilation can also be used to assist spontaneous respirations in patients not given muscle relaxants as an artificial means of supporting ventilation and oxygenation
35
Q

Indications for mechanical ventilation

A

■ apnea
■ hypoventilation/acute respiratory acidosis
■ intraoperative positioning limiting respiratory excursion (e.g. prone, Trendelenburg)
■ required hyperventilation (to lower ICP)
■ deliver positive end expiratory pressure (PEEP)
■ increased intrathoracic pressure (e.g. laparoscopic procedure)

36
Q

Complications of mechanical ventilation

A

■ airway complications
◆ tracheal stenosis, laryngeal edema
◆ alveolar complications
◆ ventilator-induced lung injury (barotrauma, volutrauma atelectatrauma), ventilator-associated pneumonia (nosocomial pneumonia), inflammation, auto PEEP, patient-ventilator asynchrony
◆ cardiovascular complications
◆ reduced venous return (secondary to increased intrathoracic pressure), reduced cardiac output, hypotension

■ neuromuscular complications
◆ muscle atrophy
◆ increased intracranial pressure

■ metabolic decreased CO2 due to hyperventilation
◆ alkalemia with over correction of chronic hypercarbia

37
Q

Changes in peak pressures in ACV and tidal volumes in PCV may reflect what?

A

changes in lung compliance and/or airway resistance – patient may be getting better or worse

38
Q

What is positive end expiratory pressure (PEEP)

A
  • Positive pressure applied at the end of ventilation that helps to keep alveoli open, decreasing V/Q mismatch
  • Used with all invasive modes of ventilation
39
Q

Tracheostomy indication

A
  • Tracheostomy should be considered in patients who require ventilator support for extended periods of time
  • Shown to improve patient comfort and give patients a better ability to participate in rehabilitation activities
40
Q

Monitoring ventilatory therapy

A
  • Pulse oximetry, end-tidal CO2 concentration
  • Regular arterial blood gases
  • Assess tolerance regularly
41
Q

Management for patients the develop a pneumothorax while on mechanical ventilation

A

chest tube

42
Q

Ventilator strategies

A
  • mode and settings are determined based on patient factors (e.g. ideal body weight, compliance, resistance) and underlying reason for mechanical ventilation
  • hypoxemic respiratory failure: ventilator provides supplemental oxygen, recruits atelectatic lung segments, helps improve V/Q mismatch, and decreases intrapulmonary shunt
  • hypercapnic respiratory failure: ventilator augments alveolar ventilation; may decrease the work of breathing, allowing respiratory muscles to rest
43
Q

Modes of ventilation

A

• assist-control ventilation (ACV) or volume control (VC)
■ every breath is delivered with a pre-set tidal volume and rate or minute ventilation
■ extra controlled breaths may be triggered by patient effort; if no effort is detected within a specified amount of time the ventilator will initiate the breath

• pressure control ventilation (PCV)
■ a minimum frequency is set and patient may trigger additional breaths above the ventilator
■ all breaths delivered at a preset constant inspiratory pressure

• synchronous intermittent mandatory ventilation (SIMV)
■ ventilator provides controlled breaths (either at a set volume or pressure depending on whether in VC or PCV, respectively)
■ patient can breathe spontaneously (these breaths may be pressure supported) between controlled breaths

• pressure support ventilation (PSV)
■ patient initiates all breaths and the ventilator supports each breath with a pre-set inspiratory pressure
■ useful for weaning off ventilator

• high-frequency oscillatory ventilation (HFOV)
■ high breathing rate (up to 900 breaths/min in an adult), very low tidal volumes
■ used commonly in neonatal and pediatric respiratory failure
■ occasionally used in adults when conventional mechanical ventilation is failing

• non-invasive positive pressure ventilation (NPPV)
■ achieved without intubation by using a nasal or face mask
■ BiPAP: increased pressure (like PSV) on inspiration and lower constant pressure on expiration (i.e PEEP)
■ CPAP: delivers constant pressure on both inspiration and expiration

44
Q

Causes of intraoperative hypoxemia

A

Inadequate oxygen supply - e.g. breathing system disconnection, obsructed or malpositioned ETT, leaks in the anesthetic machine, loss of oxygen supply

Hypoventilation

Ventilation-perfusion inequalities - e.g. atelectasis, pneumonia, pulmonary edema, pneumothorax

Reduction in oxygen carrying capacity - e.g. anemia, carbon monoxide poisoning, methemoglobinemia, hemoglobinopathy

Leftward shift of the hemoglobin-oxygen saturation curve - e.g. hypothermia, decreased 2,3-BPG, alkalosis, hypocarbia, carbon monoxide poisoning

Right-to-left cardiac shunt

45
Q

Method of weaning patients from mechanical ventilation that leads to extubation more quickly

A

Once-daily or multiple trials of spontaneous breathing led to extubation more quickly than intermittent mandatory or pressure support ventilation.

46
Q

Causes of hypocapnea end tidal

A

Hyperventilation

hypothermia (decreased metabolic rate)

decreased pulmonary blood flow (decreased cardiac output)

technical issues, incorrect placement of sampling catheter, inadequate sampling volume

V/Q mismatch, pulmonary thromboembolism, incipient pulmonary edema, air embolism

47
Q

Causes of end tidal hypercapnea

A

Hypoventilation

hyperthermia and other hypermetabolic states

improved pulmonary blood flow after resuscitation or hypotension

technical issues (water in capnography device, anesthetic breathing circuit error, inadequate fresh gas flow, rebreathing, exhausted soda lime, faulty circuit absorber valves)

low bicarbonate

Anesthesia and Perioperative Medicine (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions