Respiratory Flashcards
1
Q
Most appropriate next step for pneumediastinum
A
Observation
2
Q
Ion responsible for creating fetal lung fluid
A
Chloride (by active transort)
Chloride Creates Critical fluid
Sodium Secretion Sends it back out
3
Q
Ion responsible for clearing fetal lung fluid
A
Sodium
Chloride Creates Critical fluid
Sodium Secretion Sends it back out
4
Q
Diaphragmatic paralysis: Unilateral or Bilateral more common?
A
Unilateral
5
Q
Diaphragmatic paralysis: Right or left side more common?
A
Right
6
Q
How does diaphragm move during paralysis?
A
Rises with inspiration and falls with expiration = Kienboeck’s sign
ie. collapses with inspiration
7
Q
OI equation
A
MAP X FiO2 / postuductal PaO2 x 100
> 25 severe lung disease
40 ECMO
8
Q
Stages of lung development
A
Embryonic Pseudoglandular Cannalicular Saccular Alveolar
9
Q
When does Embryonic stage of development happen?
A
0-7 weeks
10
Q
When does Pseudoglandular stage of development happen?
A
7-17 weeks
11
Q
When does Cannalicular stage of development happen?
A
17-27 weeks
12
Q
When does Saccular stage of development happen?
A
27-36 weeks
13
Q
When does Alveolar stage of development happen?
A
36 weeks - 3-8 years
14
Q
Equation for Oxygen content
A
1.34 mL O2/g Hb x Hb x O2 sat + [0.003 x paO2]
15
Q
There is a profound effect in oxygen content with changes in ____
A
hemoglobin concentration
1.34 mL O2/g Hb x Hb x O2 sat + [0.003 x paO2]
16
Q
Ways to increase MAP
A
Increase PEEP (most effective) Increase PIP Increase iTime Increase rate Increase flow Decrease expiratory time
17
Q
Criteria for ECMO
A
FiO2 100% + A-a gradient >600
PIP >35
paO2 <40
OI >40
18
Q
Contraindications to ECMO
A
Prematurity <35w
Irreversible lung disease or Neuro abnormalities
significant coagulopathy
severe IVH
congenital anomalies with poor long term outcome
19
Q
Which is connected to pulmonary circulation? CPAM vs BPS?
A
CPAM
BPS = Systemic circulation
20
Q
Which is connected to tracheobronchial tree? CPAM vs BPS?
A
CPAM
21
Q
Ways HFOV work
A
Bulk convection Pendelluft effect Taylor dispersion Molecular diffusion Asymmetric velocity
22
Q
A-a gradient equation
A
pAO2 - paO2 = [FiO2 x (pB - pH2O)] - paCO2/R - paO2
R= 0.8
23
Q
Effects of CPAP
A
Decreases total airway resistance Inc FRC Dec WOB Dec compliance Improves gas exchange
24
Q
What stage of lung development do Type 1 and 2 pneumocytes form?
A
Canalicular
25
When are lamellar bodies formed and what are they?
Canalicular
| Storage location of surfactant in type II pneumonytes
26
Survanta made of what
Bovine lung, SP-B and C
27
Infasurf made of
Bovine lung, SP-B and C
28
Curosurf made of
Porcine lung (pig), SP-B and C
29
La Place's law
Distending P = 2xST / alveolar radius
30
Alveolarization delayed by
antenatal steroids
oxygen
nutritional deficiencies
mechanical ventilation
31
Total respiratory system resistance
chest wall R (25%) + airway R (55%) + lung tissue R (20%)
32
What makes up majority of airway resistance?
Nasal passages
| remainder of R comes from first few generations of bronchi with distal airways contributing very little
33
CDH due to
Failure of closure of the pleuroperitoneal canal at approx 8 weeks
34
Characteristics of new BPD
```
Arrest of alveolarization:
- increased alveolar diameters
- Fewer alveoli
- Disruption of the collagen network
- Localization of elastin
- Increased AND dec PECAM staining
CXR: Hyperinflation, minimal cystic emphysema
Less airway reactivity and pulmonary HTN than classic;
Minimal fibrosis
```
35
MC organism associated with chorio
Ureaplama > Mycoplasma
36
How do antenatal steroids mature the lung?
Decreasing the amount of mesenchymal tissue and increasing the potential airspace volume --> arrest of alveolar / saccular septation
37
Mild BPD
Treatment with O2 for at least 28 days +
| RA at 36 weeks or discharge
38
Moderate BPD
Treatment with O2 for at least 28 days +
| <30% FiO2 at 36 weeks or discharge
39
Severe BPD
Treatment with O2 for at least 28 days +
| >/=30% FiO2 AND/OR CPAP or NIV at 36 weeks or discharge
40
MCC PHTN in newborns
MAS
41
Meconium injures the lungs by
Mechanical obstruction --> ball valve mechanism
Chemical pneumonitis (due to release of cytokines)
Activation of complement
Inactivation of surfactant
Vasoconstriction of pulmonary vessels
42
Why does iNO not cause systemic vasodilation?
Once in the bloodstream, it binds avidly to hemoglobin, limiting its systemic vascular activity
43
iNO contraindicated in
heart disease dependent on R-L shunting across PDA ie. critical aortic stenosis, interrupted AA, hypoplast
TAPVR
44
Variables that help with exogenous surfactant distribution
```
liquid form
higher volume
faster rate of administration
higher fluid volume in lungs like right after delivery
higher gestational age
after exposure to ANS
```
45
Describe apnea due to laryngeal reflex
Stimulation of the laryngeal mucosa causes apnea by exaggerated inhibitory reflex mediated by superior laryngeal nerve
46
Methylxanthines MOA
```
Inhibition of adenosine -->
Decrease hypoxic depression of breathing
Decrease periodic breathing
Improve CO2 sensitivity
Increase diaphragmatic activity
Increase minute ventilation
```
47
What responds to CO2
Central Chemoreceptors on the ventrolateral surface of the medulla
48
What responds to O2
Peripheral chemoreceptors in the carotid and aortic bodies
49
Dead space
Volume of air that does not take place in gas exchange
| Dead ie no blood flow
50
Anatomic dead space
Lung areas such as conducting airways which are not involved in gas exchange
Bronchoconstriction decreases it
51
Alveolar dead space
Alveoli not involved in gas exchange
52
Physiologic dead space
Anatomic dead space + Alveolar dead space
53
Haldane effect
Increase in arterial pO2 reduces the affinity of hemoglobin to CO2
(Hemoglobins
Affinity
LDane- CO2)
54
Bohr Effect
CO2 and H+ affect affinity of hemoglobin for oxygen
-High CO2 and H+ decrease the affinity of hemoglobin for O2
B
Oxygen
Hydrogen
Released in tissue
55
Airway resistance during inspiration and expiration
Decreases during inspiration (bronchodilation)
| Increases during expiration
56
Choanal Atresia Mnemonic
```
CAT FUR
Choanal ATresia
Females
Unilateral
Right sided
```
57
Alveolar ventilation
(TV-dead space) x RR
Inc in neonates
58
Minute ventilation
TV x RR
Inc in neonates
59
Treatment for chylothorax
Thoracentesis + MCT formula once eating
| B/c lymphatic vessels are not required for absorption of MCT
60
Right side more common in
Diaphragmatic paralysis
Choanal Atresia
Chylothorax
61
Characteristics of chylothorax
```
Transudative
Xanthochromic or milky
Lymphocytic predominance >80%
WBC <1000
pH >7.4
Elevated protein
High TG (>110)
LDH <200
```
62
Maternal conditions ass with accelerated lung maturation and surfactant production
```
PIH and chronic HTN
IUGR
Chorio
PROM
Placental infarction
CV disease
Incompetent cervix
Hemoglobinopathies
```
63
CPAP provided by in NRP
Flow inflating bag and T-piece
| NOT self inflating bag (no flow of gas when bag not being compressed)
64
Is interrupting breathing normal in utero?
Yes. PGE2 from placenta plays a role in it.
65
How does hypoxia induce apnea?
Adenosine receptor stimulation in the pons
| Caffeine inhibits adenosine
66
Mechanisms of apnea of prematurity
Decreased response to hypercarbia (respond with inc in TV not RR)
Irritation of laryngeal mucosa --> inhibitory reflex
Hypoxic ventilatory depression to sustained hypoxia
67
Does GERD cause apnea of prematurity?
No. But AOP can cause GERD d/t relaxation of the LES
68
What enzyme does NO work on?
Guanylate cyclase in endothelial cells
Converts GTP to cGMP
Cyclic GMP increases calcium efflux leading to vascular smooth muscle relaxation
69
Clinical triad of PPHN
1) sat differential >5-10% or PaO2 >/= 20 mmHg
2) OI >/= 15
3) Lability of sats
70
Static lung compliance
Measured when no flow of gas
| Reflects elastic properties of the lung
71
Dynamic lung compliance
Measured during flow of gas
Reflects both elastic properties of the lung and resistance to flow
Impacted by RR
72
Where are Na-K-ATPase pumps located?
Basolateral cell membrane
73
Where are ENaC channels located?
Apical surface of the respiratory cell
74
P50
Oxygen tension at which 50% hemoglobin is saturated with oxygen
Fetal hemoglobin has higher oxygen affinity so has lower P50
75
Things that shift oxyhemoglobin curve to right
```
Adult hemoglobin (inc offloading)
Dec pH
Inc 2,3 DPG
Inc Temp
Inc altitude
```
76
Things that shift oxyhemoglobin curve to left
Fetal hemoglobin (inc affinity, dec offloading, Lower P50)
Inc pH
Dec 2,3 DPG
Dec Temp
77
At a constant temperature, a given volume of gas varies inversely to to the pressure to which it is subjected
Boyle's law
78
As a gas is warmed it expands, and shrinks as it is cooled
Charle's Law
79
Total pressure exerted by a mixture of gases is equal to the sum of the partial pressure of each gas
Dalton's law
80
Transfer of solute by diffusion is directly proportional to the cross sectional area available for diffusion
Fick's law
81
At a constant temperature, any gas physically dissolves in a liquid in proportion to its partial pressure
Henry's law
| “Hank Henry Sank”
82
Cause of Choanal Atresia
Failure of the bucconasal membrane to rupture during the 5th and 6th weeks
