Respiratory Flashcards
CO causes the oxygen dissociation curve to move ___
left because it increases bound O2 binding affinity
methemoglobinemia has iron in ___ state
Ferric (3+), instead of Ferrous (2+), which makes the HgB unable to bind/release O2 –> cyanosis.
Diagnosis of MtHgB
sat is low, paO2 is high; blood does not become bright red; check gas –> normal MtHgb level is 1, 10% will be cyanotic, 30-40 will be hypoxic, 70% will be dead
methylene blue works by
activating second methemoglobin reductase
causes of mthgb-emia
1) hgb M disease (structural which causes Ferric state, can affect a, b, or g chain) 2) iNO/lidocaine, 3) abnormale mthgb reductase activity
endogenous iNO moa
l-arginine becomes NO in endothelial cell of bv wall by NO synthase –> NO goes to sm cell, activates guanylyl cyclase –> GTP to cGMP to inhibit ca release and cause smooth muscle relaxation
choanal atresia
- which syndrome is most common
persistence of buccopharyngeal membrane.
CHARGE: coloboma, heart, atresia chonae, retardation of growth and dvpt, GU defects, ear anomalies. mutation in CHD7 gene on chromosome 8
congenital nasal pyriform aperture stenosis
excessive bone formation in medial nasal process of maxillary bone. Frequently associated with single maxillary incisor, midline defects (pit hypoplasia, DI, holopresencephaly), craniosynsytosis
pierre robin
glossoptosis, microagnathia, cleft; SOX9 gene
mediastinal mass
anterior: enlarged thymus, teratoma
central: bronchogenic cyst
posterior: neuroendocrine tumor, duplication cyst (from gut)
pentology of cantrell
sternal abnormality, ectopis corids, diaphragm abnormality, absent pericardium, abd wall defect, morgagni CDH, CHD
poland syndrome
Hypoplasia or absence of the pectoral muscles, typically only on one side, is termed Poland syndrome and may be associated with cartilage agenesis of the second through fifth ribs on the ipsilateral side—the ribs of attachment for the pectoralis major muscle
jeune’s syndrome
A rare deformity of the thoracic cage, asphyxiating thoracic dystrophy is an AR chondrodystrophy, associated with short-limbed dwarfism and often polydactyly. Assc with renal cystic dysplasia, displacement of organs from fixed rib cage
CPAM 5 stages
connection with tracheobronchial tree, pulm supply, assc w/ vsds
0: ~2% from tracheobronchial tree; normal lung lobulation, but no formation of alveoli; only bronchial-like structures present, indicating an arrest of development in the pseudoglandular stage; lesion is rapidly lethal because of severe, intractable respiratory failure; aka acinar dysplasia; uncommon
I: most common ~60% ; large communicating cysts, +/- a dominant cyst; usually unilateral and restricted to a single lobe; walls of the lesions resemble walls of bronchi; risk of malignant transformation in nonresected or residual CCAM tissue; bronchoalvolar carcinoma (BAC)?; assc with conotruncal anomalies
II: ~20% multiple, smaller macroscopic cysts; appear as multiple bronchiole-type structures, although intraacinar structures may also be interspersed; most commonly associated with other anomalies (b/l renal dysplasia or agenesis, GU agenesis, sirenomelia, extrapulmonary sequestration, and diaphragmatic hernia, Conotruncal cardiac malformations
III: 5% to 10%; solid, with microscopic cysts (although single larger cysts can be present); involve an entire lobe or the entire lung; mass effect with lung hypoplasia; bronchiolar and alveolar duct-type
IV: rare 10%; large cysts present; usually confined to one lobe; peripheral; lesions are lined with pneumocytes; with alveolar type I (flat) and type II (rounded) epithelial cells; cells representing the more proximal areas of the lung should raise suspicion for pleuropulmonary blastoma (PPB - malignancy potential
chylothorax
common in turner, tri 21 and noonans. treatment includes MCT feeds or non-fat feeds and somatostatin. high protein, high TGC, high lymphocyte predominance
bronchopulmonary sequesteration
intralobar: 75%, may be acquired after infection, usually require lobectomy
extralobar: less common, frequently have assc anomalies
assc with pleural effusion, may have communication with GI tract
LHR
It is the perpendicular area of the lung contralateral to the hernia at the level of the cardiac atria divided by the biparietal diameter. It has been used predominantly in mid-gestation (22 to 27 weeks), with an LHR ≤1.0 combined with liver herniation accepted as the most severe group of CDH.
Scimitar syndrome
right lung hypoplasia, partial anomalous pulmonary venous return, and unilateral pulmonary sequestration
surfactant
A: hydrophillic, most abundant, immune, role in tubular myelin formation, not in exogenous surf. def assc w/ increased severity of rds and dvpt of cld
B: hydrophobic, integral for survival - lethal RDS without
C: hydrophobic, seen as interstitial lung disease
CF
meconium ileus - highest predictive value
also assc w/ elevated IRT on NBS, rectal prolapse, maternal CF, heterozygosity for D-F508. Diagnostic study: sweat chloride test, (+) if >40 meq/L, can be tested after 3 w.
IRT: immunorective trypsinogen is a pancreatic enzyme released during pan. injury and birth. If elevated, f/u with repeat or genetics.
AR invloving gene for CFTR on chr. 7
What is the difference between intra-alveolar and extra-alveolar capillaries?
Intra-alveolar capillaries are in the septum between alveoli. They get compressed with alveolar distention.
Extra-alveolar capillaries are no affected by the alveolar pressure. They get distended when the alveoli get distended. Ideal PVR is attained when ideal FRC is attained –> this puts intra-alveolar and extra-alveolar capillaries at a balance.
What is Head’s Paradoxical Reflex?
This is the irritant receptor response to stretch. When there is a rapid inflation of the lung, it induces a sigh/gasp/deep inspiration. Likely primarily has effect in first day after birth, and maybe later on in neonatal sighs.
What is the Hering Beuer Reflex?
This is the stretch receptor response to stretch causing apnea. When there is a sustained inflation/increase in TV, inspiratory time increases to cause apnea.
what are characteristics of fetal lung fluid
almost no bicarb (high Cl), very acidic, low protein to have low oncotic pressure to have movement of fluid out of alveoli into interstitium
what percentage of fetal lung fluid is evacuated at birth
prelabor 100% present, 40% present at birth
which channels are responsible for fluid movement in and out of alveoli?
in: Cl channel
out: ENAC channels into cells, Na/K ATPase out of cells into intersititum
what is the relationship between PGs and lungs?
lungs metabolize prostoglandin. In utero, very low movement through lung so PG around to keep ductus open.
1% FiO2 = ? torr paO2?
7
what is the bohr equation
paCO2 (arterial) - peCO2 (end tidal) / paCO2 = Vd/Vt
what is one TC? 3? 5?
time to equilibrate volume to 63%, 95%, 99%
normal time constant is 0.12sec, normal it 0.6
what is fick principle
o2 consumption = q(cao2 - cvo2)
which organ does lung formation coincide with?
kidneys
which surfactant genetic abnormality is most common?
abca3 - AR
abca3 and surf B present in neonatal period
surf C usually not neonatal
surf D deficiency doesn’t exist
In a neonate which volumes are increased, decreased and the same compared to an adult?
Increased: residual volume
Decreased: tv ( and so IC, VC and TLC)
Same: FTC and dead space
Increased: rr and so mv, alveolar ventilation
What does 2,3 dpg do to hgb?
Stabilizes deoxy form, makes it less likely to hold onto oxygen, more likely to dissociate (shift to the right)
what type of effusion is a chylothorax?
transudative (exudative is inflammatory)
<1000 WBC, < 200 LDH, pH alkalotic
in NAVA, what is: EDI peak EDI min EDI trigger NAVA level plateau
EDI peak: measure of respiratory drive
EDI min: tonic activity of diaphragm, effort to keep FRC
EDI trigger: min increase in electric activity from prior baseline that will trigger vent, so breath is detected as breath
NAVA level: conversion factor that converts EDI signal into pressure
plateau: a level after which additional titration does not increase piP or TV, but downregulates EDI
what is static vs dynamic compliance?
static: when there is no gas flow, reflects elastic properties of lung
dynamic: there is flow, includes elastic properties and resistance to flow and RR
