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GNURS627-Resp > Respiratory Final > Flashcards

Respiratory Final Flashcards

1
Q

What are high risk results from PFT’s?

A

FEV1 < 2L
FEV1/FVC ratio < 0.5%
VC adults < 15cc/kg/ child <10cc/kg
VC < 40-50% of predicted value

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2
Q

What are post operative extubation criteria?

A
  • VSS, awake, alert, RR < 35
  • On 40% FiO2, PaO2 > 70mmHg , PaCO2 < 55
  • MIF MORE than -20 cmH2O
  • VC > 15cc/kg
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3
Q

MECHANICAL intubation criteria?

A
  • RR > 35,
  • VC <15cc/kg adult, VC , 10cc/kg child
  • MIF LESS negative than -20 cmH2O
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4
Q

OXYGENATION intubation criteria?

A
  • 40% FiO2, PaO2 < 70mmHg

- A-a gradient > 350mmHg on 100% O2

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5
Q

VENTILATION intubation criteria?

A
  • PaCO2 > 55 ( except chronic hypercarbia/COPD)

- Vd/Vt > 0.6 ( 30% anatomical dead space)

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6
Q

CLINICAL intubation criteria ?

A
  • Airway burn
  • Chemical Burn
  • Epiglottis ( usually small children)
  • Altered Mental Status
  • Rapidly declining pulmonary function
  • Fatigue ( common in elderly)
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7
Q

What are your normal ABG values?

A 
pH:  7.35 – 7.45
PCO2:  35 – 45 mmHg
PO2:  75 – 105 mmHg
Bicarbonate:  20 – 26 mmoles/L
Base excess:  -3 to +3 mmoles/L
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8
Q

What does an increasing or decreasing CO2 by 10mmHg do to your pH?

A

Inversely decreases or increases by 0.08

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9
Q

What is hypoxemia?

A

Decreased BLOOD PO2 < 75

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10
Q

What is hypoxia?

A

A low O2 state.

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11
Q

What is the A-a gradient?

A

Measures lung efficiency

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12
Q

What is the equation for PAO2?

A

= (PB - PH2O) x (FiO2) - ( PaCO2/0.8)

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13
Q

What is a roughly a normal A-a gradient?

A

Age/3

- Should be less than 20mmHg difference

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14
Q

When is the A-a gradient widened?

A 
V/Q mismatch
Pneumothorax
Shunt 
PE
Diffusion Issues
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15
Q

T/F: The A-a gradient normal with hypoventilation and low FiO2?

A

TRUE

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16
Q

How do you manage an abnormal A-a gradient?

A

Treat underlying cause

  • Supplemental O2
  • Adjust ventilation
  • add PEEP
  • Treat atelectasis
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17
Q

What equation is bicarbonate calculated from?

A

H= 24 x ( PaCO2/ HCO3)

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18
Q

An increase or decrease in bicarb by 10mmoles does what to your pH?

A

A directly proportionate increase and decrease by 0.15

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19
Q

What is the equation for TOTAL body bicarb deficit?

A

deficit = base deficit x weight in kg x 0.4 = in mEq/L

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20
Q

How much total body bicarb deficit do you replace?

A

replace 1/2 the deficit

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21
Q

Respiratory acidosis, an acute cause?

A
  • Hypoventilation with Hypercarbia ( opioids)
  • CNS depression – trauma, drugs
  • Decreased FRC – obesity ( osa)
  • Upper or lower airway obstruction
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22
Q

Chronic cause of respiratory acidosis?

A
  • COPD
  • Emphysema
  • Asthma
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23
Q

How does the Body compensate for respiratory acidosis?

A

1-2 Days KIDNEYS compensate increasing H+ excretions and increase HCO3 being absorbed into the blood.
= increasing HCO3 value, and PARTIALLY restoring pH

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24
Q

What are causes of respiratory alkalosis?

A

Hyperventilation with Hypocarbia

  • -PRENANCY
  • -Anxiety
  • -Hypoxic respiration ( mountain climbing )
    • Artificial ventilation
  • -CNS disorders
  • -Encephalitis
  • -Narcotic Withdraw
  • -Early septic shock
  • -Hypermetabolic states
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25
Q

How does the body compensate for respiratory alkalosis?

A

Kidneys increase HCO3 excretion and retain H+ = partially correcting pH and resulting in a lower HCO3

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26
Q

What are causes of metabolic acidosis?

A
  • Trauma ( hypoperfusion) = Lactic acidosis
  • DKA
  • ASA ingestion
  • High protein intake
  • Diarrhea ( losing HCO3)
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27
Q

How does the body compensate for metabolic acidosis?

A

-Respiratory ( central chemoreceptors) with HYPOCARBIA
- More rapid than renal compensation
-Eventual H+ excretion from the kidneys
= lowering CO2 and partially correcting pH

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28
Q

What are causes of metabolic alkalosis?

A
  • Bicarb over infusion

- Vomiting or excessive NG suction ( H+ loss)

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29
Q

Compensation for metabolic acidosis?

A

Respiratory compensation –>hyperventilate,
-However hypoventilation is limited due to eventual hypoxic drive
= increasing CO2 retention and partial correction in pH

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30
Q

T/F: Pulse oximetry is a mandatory intraoperative monitor?

A

True

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31
Q

Infrared light represents what? and is measured at what wavelength?

A

Oxyhemoglobin - 940nm

Corresponds with 100% saturation

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32
Q

Red light represents what? and is measured at what wavelength?

A

Deoxygenated hemoglobin and 660 nm

-Corresponds to 50% saturation

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33
Q

Hemoglobin variants

Describe carboxyhemoglobin

A

From CO2 poisoning, is viewed as oxyhemoglobin by the pulse ox and shows up as 100%
-This is an overestimation of the true oxygenation, co oximeter used to distinguish between the two

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34
Q

What happens in Methemoglobin ?

A

Fe2 in Hb is oxidized to Fe3 and cannot transport O2, cyanosis seen when 15% of Hg is in methemoglobin form
**Absorbs equally at both wavelengths 1:1 shows an SpO2 of 85%

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35
Q

What causes Methemoglobin ?

A
  • Nitrates
  • Nitrites
  • Nitroglycerine
  • Nitroprusside
  • Sulfonamides
  • Benzocaine ( hurricane spray)
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36
Q

How do we treat Methemoglobin?

A

Low does methylene blue

-Ascorbic acid

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37
Q

What two things do not affect the pulse oximetry?

A

Fetal Hemoglobin and bilirubin

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38
Q

Capnograhy: Rapidly and reliably indicates _____ intubation but does not reliably detect ______ intubation

A

Esophageal

Endobronchial

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39
Q

What is the gold standard for tracheal intubation

A

End-tidal CO2

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40
Q

During surgery where a pt is in the lateral position, which long will be better ventilated? Is this a problem?

A

The nondependent lung will be better ventilated but the dependent lung will be better perfused causing a V/Q mismatch.

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41
Q

In the ____ and ____ position the dependent lung is better perfused (gravity) and ventilated

A

Awake & Lateral

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42
Q

Positive pressure ventilation favors the upper or lower lung and why?

A

The upper lung because it is more compliant.

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43
Q

T/F: The upper lung is favored.

A

True

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44
Q

T/F: Hypoxic pulmonary vasoconstriction improves a the right-to-left shunt.

A

True

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45
Q

Factors that inhibit hypoxic pulmonary vasoconstriction.

A
  • Very high or very low pulmonary artery pressure
  • Hypocapnia
  • High or low mixed venous PO2
  • Vasodilators (NTG, Nitroprusside, Beta-adrenergic agonist, calcium channel blockers)
  • Pulmonary infections
  • Inhalation agents.
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46
Q

During OLV what should your FiO2 be?

A

80-100%

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47
Q

Tidal Volumes should be kept at ______ during OLV.

A

10cc/kg

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48
Q

How do you ensure placement during OLV?

A

Fiberoptic scope

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49
Q

Add ___ of CPAP to nondependent lung and add ___ PEEP to dependent lung

A

5cm H2O for both

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50
Q

Malignant Hyperthermia is triggered by what?

A

Inhalation agents (not N2O), and/or succinylcholine.

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51
Q

Malignant Hyperthermia leads to an acute __________ state

A

Hypermetabolic

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52
Q

T/F: The ryanodine receptor (Ca release channel) fails in the sarcoplasmic reticulum leasing to decrease in Ca reuptake

A

True. This causes increase intracellular Ca leading to sustained muscle contraction, glycolysis, and heat production.

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53
Q

Malignant Hyperthermia has abnormal excitation-contraction coupling which results in what?

A

Prolonged and irreversible muscle contracture

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54
Q

What is the first most sensitive sign of MH?

A

Unexplained tachycardia

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55
Q

What is the most specific sign of MH?

A

Increase EtCO2- hypercapnia. Also decrease in SaO2 and SpO2.

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56
Q

What are the signs and symptoms of MH?

A

Muscle rigidity, dysrhythmias, tachypnea, cyanosis, sweating, unstable BP, mottling, trismus (masseter spasm), cola-colored urine, hyperthermia (least sensitive sign)

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57
Q

What would labs looks like in MH?

A

Metabolic Acidosis then a combined metabolic respiratory acidosis, hyperkalemia, hypercalcemia, hyperphosphatemia, creatinine kinase (CK) >1000 IU, myoglobinuria, hypoxemia

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58
Q

What is diffusion hypoxia?

A

This results from the dilution of alveolar O2 concentration by a large amount of N2O “outgasing” or leaving the pulmonary capillary blood at the conclusion of N2O administration.

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59
Q

How do you avoid diffusion hypoxia?

A

Administering 100% O2 following N2O use.

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60
Q

Factors that increase MAC

A
  • *Age: term infant to 6 months of age has the highest MAC requirements
  • Hyperthermia
  • *Chronic EtOH abuse
  • Hypernatremia
  • Drugs that increase CNS catecholamine.
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61
Q

Factors that decrease MAC

A
  • Hyperthermia
  • IV anesthetics, opioids,
  • Preop Meds
  • Neonate/Premature infants
  • Elderly
  • *Pregnancy
  • Acute EtOH ingestion
  • Lithium
  • Cardiopulmonary Bypass
  • Hyponatremia
  • Alpha 2 agonist (precede)
  • Calcium Channel Blockers
  • Severe Hypoxemia (PaO2 <38mmHg)
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62
Q

Factors that have no effect on MAC

A
  • *Thyroid gland dysfunction
  • Gender
  • Hyper/Hypokalemia
  • Hyper/hypocarbia
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63
Q

What is the second gas effect?

A

The ability of a large volume uptake of a first gas (N2O) to accelerate the rate of rises of the alveolar partial pressure of a concurrently administered companion gas (agent) thus speeding induction).

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64
Q

What is an example of the second gas effect?

A

Alveolar space: 70% N2O, 30% O2 and ISO 1% -> rapid uptake of 1/2 of the N2O -> 35% O2, and ISO now 1.53%

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65
Q

Nicotine stimulates sympathetic ganglia, which releases ________ from the ________ ________ and causes an increase in what?

A

Releases catecholamines from the adrenal medulla, increasing HR, BP, and SVR. This persists for 30 minutes after last cigarette.

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66
Q

25 pack per year increases physiologic age by how many years?

A

8 years

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67
Q

What is important for airway management in a smoker?

A

Pre-O2 well and avoid instrumentation of airway until deep level of anesthesia

68
Q

You should advise patients to stop smoking how many hours prior to surgery?

A

12 hours. Will reduce COhb and nicotine levels to that if nonsmokers.

69
Q

Cessation if greater than __ weeks will reduce post-op __________ _________.

A
  • Greater than 8 weeks

- Reduce Postop pulmonary complications

70
Q

What is a normal I:E ratio?

71
Q

What is the I:E ratio for someone with COPD?

72
Q

T/F: In a patient with COPD, ETCO2 should be kept near the patient’s baseline, because a rapid correlation could cause metabolic alkalosis.

73
Q

T/F: a COPD patient could laryngospasm due to secretions.

A

True. Section ETT frequently.

74
Q

What medications do you want to avoid during a bronchospasm and why?

A

Histamine Releasing Drugs

  • Pentothal
  • Morphine
  • Atracurium
  • Mivacurium
  • Neostigmine
75
Q

Location of the larynx at birth vs an adult?

A

At Birth: level T C3-4

Adult: anterior to 3rd-6th cervical vertebrae

76
Q

What is a normal A-O extension?

A

35 degrees

77
Q

What is a mallampati class 1?

A

Full view of uvula and tonsillar pillars, soft palate

78
Q

What is a mallampati class 2?

A

Partial view of uvula or uvular base partial view of tonsils, soft palate

79
Q

What is a mallampati class 3?

A

Soft palate only

80
Q

What is a mallampati class 4?

A

Hard palate only

81
Q

Airway innervation: where does the sphenopalatine ganglion innervate?

A

(Middle division of the CN V)- Nasal Mucosa, superior pharynx, uvula, tonsils

82
Q

Airway innervation: what does the glossopharyngeal nerve innervate?

A

(CN IX) (lingual back 1/3, pharyngeal, tonsillar nerves) - Ora pharynx, supraglottic region

83
Q

Airway innervation: what does the internal branch Superior Laryngeal Nerve innervate?

A

(CNX)- mucus membrane above the VC’s, glottis

84
Q

Airway innervation: what does the recurrent laryngeal nerve innervate?

A

(CNX)- trachea below VCs

85
Q

Stimulation of the internal SLN can cause what?

A

Laryngospasm

86
Q

The external SLN provides what?

A

Motor innervation of cricothyroid muscle.

87
Q

T/F: the RLN provides motor innervation to all larynx except cricothyroid muscle

88
Q

Damage to the RLN causes the vocal cords to do what?

89
Q

Stimulation of the RLN causes the vocal cords to do what?

90
Q

What is the narrowest part of the airway in a child vs an adult?

A

Child: cricoid
Adult: vocal cords

91
Q

How many C shaped cartilages make up the trachea?

92
Q

What is the diameter and length of the trachea?

A

Diameter: 18-20mm
Length: 12.5-18cm

93
Q

Where does the trachea extend to? Where does the carina extend to?

A
  • Trachea: C6-T5

- Carina at level T5-7

94
Q

T/F: there is some gas exchange in the respiratory bronchiole?

A

True. **Review slide 12

95
Q

What nerves transmits motor stimulation to the diaphragm?

A

Phrenic Nerves C3,4,5

96
Q

Where are the intercostal nerves located that send signals to the external intercostal muscles?

97
Q

T/F: the act of inhaling is a positive-pressure ventilation

A

False: spontaneous respirations are negative pressure.

98
Q

T/F: total lung capacity is the sum of all capacities and reserves, and can be measured with spirometry

A

False. It cannot be measured with spirometry.

99
Q

What is FRC (functional residual capacity) the sum of?

A

Expiratory Reserve Volume and Residual Volume

100
Q

How can FRC and TLC be determined?

A
  1. Helium dilution
  2. Nitrogen washout
  3. Body plethysmography
101
Q

Know the limbs of the flow-volume loop

A

Bottom inspiratory- semi circle shape

  • Top limb Expiratory - pizza slice shape
  • Slide 19
102
Q

Be able to identify the following flow volume loops

A
  • Fixed Obstruction
  • Extra thoracic obstruction
  • Intra thoracic obstruction
  • Slide 20
103
Q

Surfactant lowers surface tension of the alveoli and lunch by doing what?

A
  • Increases compliance

- Reduces work of breathing

104
Q

How does surfactant behave to promote stability in the alveoli?

A
  • 300 million tiny alveoli have tendency to collapse
  • surfactant reduces forces causing atelectasis
  • assists lung parenchyma “interdependent” support
105
Q

Prevention of transudation of fluid into alveoli is accomplished by surfactant doing what?

A
  • Reducing surface hydrostatic pressure effects

- Prevents surface tension forces from drawing fluid into alveoli from capillary

106
Q

Equation for Poiseuille’s Law?

A 
R= (8 x L x n) / ( Pie x r4)
R= resistance to flow in a tube
L= length of the tube
n= viscosity of the fluid
pie = 3.14
r = radius of the tube ( to the 4th power)
107
Q

Reducing r ( the radius) by 16% will do what to R ( resistance)

108
Q

Reducing r ( radius) by 50% will do what to R ( resistance?

A

Increase 16 fold

109
Q

Pulmonary Hemodynamics : pressures in each chamber of the heart

A 
RA: 2-3
RV: 25/0
PA: 25/8 (mean 14)
Pulmonary capillaries  8-12
LA: 5-8
LV: 120/ 0
Systemic Arteries: 120/80
Systemic cap: 10-30

***Review slides 23 & 24

110
Q

What are two mechanisms to decrease PVR that occurs when vascular pressures are raised?

A
  • Recruitment

- Distension

111
Q

The pulmonary capillaries are an extensive network within the alveolar walls and cover what parent of the capillary surface?

112
Q

T/F: Total capillary surface area almost equals alveolar surface area?

113
Q

Functional capillary volume, it increases by opening closed segments in what manner?

A

Recruitment

  • *70 ml ( 1ml/kg body weight) normal volume at rest
  • *200 ml at maximal anatomical volume
114
Q

Alveolar gas exchange occurs over ___ seconds, and ___PCO2 diffuses out into the lungs and ___ PO2 diffuses into the lung capillary?

A
  • 0.75 seconds
  • 40mmHg
  • 100 mmHg

*Diagram slide 27

115
Q

What are the pressures of the alveoli, arteries, and venous capillaries in the different zones of the lung?

A
  • Zone 1 : PA>Pa> Pv
  • Zone 2: Pa>PA> Pv
  • Zone 3 : Pa > Pv > PA - ideal
116
Q

Where is the ventilation perfusion ratio most optimal in an awake sitting patient?

A

Dependent lung

**Slide 29 graph

117
Q

List factors that vasoconstrict increasing pulmonary vascular resistance?

A
  • *Reduced PAO2
  • *Increased PCO2
  • *Histamine
  • Thromboxane A2
  • alpha- adrenergic catecholamines
  • Angiotensin
  • Prostaglandins
  • Neuropeptides
  • Leukotrienes
  • Serotonin
  • Endothelin
  • Norepinephrine
118
Q

Name vasodilators that decrease vasomotor tone

A
  • *Increased PAO2
  • *Nitric Oxide
  • Prostacyclin
  • B-adrenergic catecholamines
  • Acetylcholine
  • Bradykinin
  • Dopamine
  • Isoproterenol
119
Q

T/F: Alveolar hypoxia inhibits hypoxic pulmonary vasoconstriction(HPV) ?

A

False

- produces (HPV)

120
Q

How does alveolar hypoxia cause vasoconstriction?

A
  • Localized response of pulmonary arterioles
  • Caused by hypoxia and enhanced by hypercapnia and acidosis
  • Contraction of smooth muscle in small arterioles in hypoxic region

**Opposite reaction than systemic circulation

121
Q

Why is HPV an important mechanism of balancing the V/Q ratio?

A
  • **Shift of flow to better ventilated pulmonary regions

- Results from decreased formation and release of Nitric Oxide by pulmonary endothelium in hypoxic region

122
Q

Oxygen is continuously absorbed into blood from the alveoli breathed in from the atmosphere, what is the partial pressure controlled by?

A

Rate of absorption and ventilation

123
Q

T/F: Normal alveolar PO2 is 100mmHg, the rate of ventilation and oxygen pressure will affect the alveolar PO2 during exercise?

A

True

  • From 250ml O2/min to 1000ml/O2 min.
  • alveolar ventilation (L/min)
124
Q

T/F: CO2 is formed in the body and is discharged into alveoli and removed by ventilation, a normal alveolar PCO2 value of 50mmHg?

A

False

-All correct , EXCEPT normal is 40 mmHg.

125
Q

Alveolar PCO2 increase in proportion to CO2 excretion, the PCO2 value ____ in inverse to alveolar ventilation?

126
Q

What is normal CO2 production?

A

200mlCO2/min

*800 mlCO2/min

127
Q

Expired air is a combination of what?

A

Dead space and alveolar air

-Dead space exhaled first than second portion is a mixture of both

128
Q

When is alveolar air expired?

A

End of exhalation

129
Q

What is Fick’s Law of diffusion equation?

A

Diffusion = (A x p-p x D) / T
D= diffusion of gas through a tissue membrane
A = cross sectional area of membrane
p-p: driving pressure ( pp difference )
D= gas coefficient
T= Tissue thickness or length through the membrane

130
Q

Normal V/Q gas exchange pathway?

A

Pa: PVO2 = 40mmHg & PVCO2 = 46 mmHg

  • Alveoli- CO2 goes in, O2 diffuses out into capillary
  • Pulmonary vein:PaO2 = 100mmHg & PaCO2 = 40 mmHg
131
Q

T/F: Physiologic Shunt is when the V/Q is above normal?

A

False
-Below normal
Shunt = perfusion but no ventilation
- Blood is being shunted from the pulmonary artery to pulmonary vein without participating in gas exchange

132
Q

In a shunt, inadequate ventilation leads to what?

A
  • A fraction of deoxygenated blood passing through the capillaries and not becoming oxygenated
  • Physiologic shunt is total amount of shunted blood per minute
  • *The greater the physiologic shunt the greater the amount of blood that FAILS to be oxygenated in the lungs
133
Q

Where the V/Q ratio is greater than normal there is a larger amount of what?

A

DEADSPACE

- ventilation to alveoli is good but blood flow is low (perfusion )

134
Q

Physiologic dead space includes what two things?

A

Wasted ventilation

Anatomical dead space

135
Q

T/F: When physiologic dead space is great, much of the work of breathing is wasted effort b/c ventilated air does not reach the blood?

A

True

Ex: PE

136
Q

When your SaO2 sat reads 95,90, 75, what is your PaO2 respectively?

A

75
60
40

**Rough rule PaO2 40,50,60
SaO2: 70,80, 90

137
Q

What is your Hb P50 point?

A

Sat 50
PaO2-27
- Point at which 50 percent of the hemoglobin are saturated with oxygen

-Slide 40

138
Q

Understand the PO2 of the blood undergoing the venous admixture

139
Q

The Hemoglobin’s affinity for oxygen equilibrium curve is modified by a number of physiological or pathological factors , and affected in what two ways?

A

1- Shift in position

2- Change in shape

140
Q

T/F: A change in shape indicates less of an interference with the O2 transport than the curve shift

A

False

-Change in shape indicates a greater interference

141
Q

What happens in a Right Hb-O2 shift?

A

-Hb has LESS affinity for O2, releases O2 to tissues, saturation will be less for a given PO2

142
Q

What are the causes of a right shift in the Hb-O2 curve?

A
  • increases CO2-cellular metabolism
  • increase temp- increase metabolism and muscle
  • increase H+ - acidosis, lactic acid production, BOHR effect
  • increase 2,3 DPG - generated by glycolysis during anaerobic metabolism, bings to Hb and decreases affinity for O2
143
Q

What happens in a L shift of the Hb- O2 curve?

A

Hb has HIGHER affinity for O2,

  • binds O2 ( stays on the hgb molecule )
  • saturation will be higher for a given PO2
144
Q

How do you describe the O2 content in the blood-CaO2

A

The sun of O2 carried on Hb AND dissolved in plasma

145
Q

What is the O2 blood content equation?

A

CaO2 = ( SO2 x [Hb] x 1.31 ) + ( PO2 x 0.003)

CaO2= O2 content in blood (ml/dL)

  • SO2 = Hb Sat ( pulse ox or ABG) as a PERCENT
  • [Hb]- Hb conc in gm/dL
  • 1.31: O2 binding to Hb ( ml/gm)
  • PO2 : arterial blood’s pp of O2
  • 0.003- Disolved O2 in blood
146
Q

What is an example of the O2 content in blood?

A

Pt with sat. of 97%, Hb 15, and PO2 200: CaO2 = (0.97 * 15 * 1.31) + (200 * 0.003) CaO2 = (19) + (0.6) ml/dL

147
Q

How do we calculate Oxygen delivery in the blood?

A

DO2 = CaO2 x CO

148
Q

How is most CO2 transported the body?

A

BICARBONATE ( HCO3)

  • 70%
  • Hgb x CO2 = 23 %
  • CO2 - 7 %
149
Q

What accelerates the product of bicarb from H2O and CO2?

A

Carbonic anhydrase

150
Q

What does the dorsal respiratory group ( DRG)control?

A

Inspiration and respiratory rhythm

151
Q

Where is the DRG anatomically?

A

Extends most of the length of the medulla with most of the DRG neurons contained in the nucleus of the tracts solitarius

152
Q

What nerves deliver sensory information to the DRG?

A

Vagal (X)
Glossopharyngeal ( IX)

-Also receives peripheral sensory signals for aid in control of respiration

153
Q

DRG receives signal from what 3 sources?

A

1-Peripheral chemoreceptors
2- Baroreceptors
3- Lung receptors

154
Q

Chemo-sensitive area of brainstem is a highly sensitive area on the -___medulla = ____chemoreceptors?

A

Ventral

Central

155
Q

Chemo-sensitive area responds to changes in what?

A

-Blood PCO2 or H+ ion concentration

**Also stimulates other portions of the respiratory center

156
Q

Effects of blood CO2-

T/F: respiratory center activity is increases very strongly by elevations in blood CO2 levels?

157
Q

CO2 has a potent direct affect via what ion on what area of the brain?

A
  • H+

- Chemo-sensitive

158
Q

***Is CO2 highly permeable to the BBB?

A

YES- hence by blood and brain concentrations are equal

159
Q

CO2 reacts with H20 to form what?

A

Carbonic acid

- Which dissociates into hydrogen & bicarbonate ions in interstitial fluid of medulla or CSF

160
Q

The released Hydrogen ions in the brain do what?

A

Stimulate respiratory center activity

161
Q

Blood PCO2 & pH effect alveolar ventilation

PCO2 changes cause what?

A

Rapidly cause changes in RATE of pulmonary ventilation

162
Q

A drastic increase in ventilation caused by _____ in PCO2

163
Q

Ventilation is greatly increased with blood PCO2 above what level?

A

35mmHg

  • Steep part of curve
  • *slide 50
164
Q

The size of the effect on respiration by a decrease in pH?

A

Smaller increase

*Change in respiration is 10 times less with blood pH range between 7.3 - 7.5

165
Q

Where are the peripheral chemoreceptors located?

A 
Carotid Body
- bifurcation
-afferent nerve fibers pass via CN IX ( glossopharyngeal) to act on DRG
Aortic Body:
-Aortic arch
-CN X ( Vagus ) DRG
166
Q

Stimulation of peripheral chemoreceptors is cased by what?

A

Decrease in arterial O2 content

167
Q

Impulse rate is sensitive to drops in PaO2 from what range?

A

30mmHg to 60 mmHg ( hypoxia)

**This range is when the hemoglobin- oxygen saturation decreases rapidly

GNURS627-Resp (1 decks)

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