UNIT 1 Respiratory & Airway π« Flashcards
(95 cards)
Which muscles tense and relax the vocal cords?
Tense: CricoThyroid
Relax: ThyroaRytenoid
The CricoThyroid muscle tenses the vocal cords, while the ThyroaRytenoid muscle relaxes them.
Which muscles abduct and adduct the vocal cords?
Abduct: Posterior CricoArytenoid
Adduct: Lateral CricoArytenoid
The Posterior CricoArytenoid muscle opens the vocal cords, while the Lateral CricoArytenoid muscle closes them.
Describe the sensory innervation of the upper airway.
Trigeminal (CN5):
* V1 β ophthalmic β nares, anterior 1/3 septum
* V2 β maxillary β turbinateβs & septum
* V3 β mandibular β anterior 2/3 tongue
Glossopharyngeal (CN 9):
* posterior 1/3 tongue
* soft palate
* oropharynx
* vallecula
* anterior side of epiglottis
SLN β internal branch:
* posterior epiglottis to vocal cords
RLN:
* below vocal cords to trachea
Sensory innervation is crucial for procedures like fiberoptic intubation and airway blocks.
How does RLN injury affect the integrity of the airway?
Bilateral: acute = respiratory distress, chronic = none
Unilateral: none
RLN injury can lead to significant airway complications depending on whether it is bilateral or unilateral.
How does SLN injury affect the integrity of the airway?
Bilateral: hoarseness / none
Unilateral: none
SLN injury primarily affects voice quality without significant airway obstruction.
Name 3 airway blocks and identify the key landmarks for each.
- Glossopharyngeal block β palatoglossal arch at anterior tonsillar pillar
- SLN block β greater cornu of hyoid bone
- Transtracheal block β cricothyroid membrane
Understanding these landmarks is vital for effective airway management.
What are the 3 paired and 3 unpaired cartilages of the larynx?
Paired:
* Corniculates
* Cuneiforms
* Arytenoid
Unpaired:
* Epiglottis
* Thyroid
* Cricoid
The cartilages play essential roles in vocalization and airway protection.
What is the treatment for laryngospasm?
- Larsonβs Point maneuver
- Positive pressure / CPAP 15-20cmH2O
- 100% FiO2
- Remove noxious stimulation
- Deepen anesthesia
- Open airway (chin lift, head extension)
- Suxx
Infants/small children should receive 0.02mg/kg Atropine with Suxx; Suxx is contraindicated in certain cases.
Describe how the respiratory muscles function during the breathing cycle.
Inspiration:
* Diaphragm contracts, increasing thoracic volume
* External intercostals contract, increasing A/P dimension
* Accessory muscles: sternocleidomastoid + scalene
Exhalation:
* Passive usually, active in conditions like COPD
* Forced exhalation involves abdominal musculature
The mechanics of breathing rely on muscle contractions and lung recoil.
What is the difference between minute ventilation (Ve) and alveolar ventilation (VA)?
Ve = RR x Vt
VA = (Vt β anatomic dead space) x RR
VA measures the volume available for gas exchange, while Ve includes all ventilation.
Define the 4 types of dead space (Vd).
- Anatomic β conducting airway
- Alveolar β vented but not perfused
- Physiologic = Alveolar + Anatomic
- Apparatus β equipment
Understanding dead space is critical for assessing ventilation efficiency.
What does the V/Q ratio represent?
V/Q = ventilation / perfusion
Normal V/Q = 0.8
> 0.8 = dead space
< 0.8 = shunt
The V/Q ratio is essential for understanding lung function and gas exchange.
Define the West Zones of the lung.
Zone 1: PA > Pa > Pv (dead space)
Zone 2: Pa > PA > Pv (waterfall, normal)
Zone 3: Pa > Pv > PA (shunt)
Zone 4: Pa > Pist > Pv > PA
These zones describe regional variations in blood flow and ventilation in the lungs.
Recite the alveolar gas equation.
Alveolar Oxygen = [FiO2 x (Pb β PH2O) β (PaCO2 / RQ)]
This equation illustrates the relationship between various factors affecting alveolar oxygen concentration.
What is the A-a gradient and what factors affect it?
A-a gradient = PAO2 - PaO2
< 15 mmHg is normal
Increased by: high FiO2, aging, vasodilators, R to L shunts, diffusion limitation
A-a gradient helps diagnose hypoxemia causes by quantifying venous admixture.
List the 5 causes of hypoxemia.
- Hypoventilation
- V/Q mismatch
- Shunt
- Diffusion impairment
- Low inspired oxygen
Supplemental oxygen can reverse some causes, primarily those related to hypoventilation and V/Q mismatch.
Define the capacities and give reference values for each.
TLC β 6L
VC β 4.5L
IC β ~ 3.5L
FRC - ~ 2.3L
Lung capacities are important for assessing respiratory function.
What factors influence FRC?
FRC = RV + ERV (35 ml/kg)
Decreased FRC: anything that reduces outward lung expansion
FRC is crucial in understanding lung mechanics and can be affected by various conditions.
What tests can measure FRC?
- N2O washout
- Helium wash in
- Body plethysmography
These tests provide valuable information about lung volumes that spirometry cannot measure.
What is closing volume and what increases it?
Closing volume is the volume above RV where small airways collapse during expiration. Increased by: CLOSE-P
* C β COPD
* L β LVF
* O β obesity
* S β surgery
* E β extreme age
* P β pregnancy
Closing volume is important for understanding airflow limitation in lung diseases.
State the equation and normal value for oxygen-carrying capacity.
(1.34 x Hgb x SaO2) + (PaO2 x 0.003) = CaO2
Normal β 20 mL O2/dL
This equation quantifies the amount of oxygen carried in the blood.
State the equation and normal value for oxygen delivery.
DO2 = CaO2 x CO x 10
Normal β 1000 mL O2/min
Oxygen delivery is critical for assessing tissue oxygenation.
Discuss the factors that alter the oxyhgb dissociation curve.
Left shift = LOVES O2 (Lungs):
* β temp
* β CO2
* β 2,3 DPG
* β H+
* alkalosis (β pH)
* β HgbMET, HgbF, HgbCO
Right shift = RELEASE O2 (Hot, exercising muscle):
* β temp
* β CO2
* β 2,3 DPG
* β H+
* acidotic (β pH)
Understanding the shifts in the curve helps in managing patients with respiratory issues.
How is carbon dioxide transported in the blood?
- Bicarbonate = 70%
- Bound to Hgb = 23%
- Dissolved in plasma = 7%
The majority of carbon dioxide is transported as bicarbonate, which plays a significant role in acid-base balance.