Respiratory Flashcards
What is the goal of Arterial O2 sats?
> 94% (healthy patient)
COPD 88-92%
What is the goal for Arterial O2 tension (PaO2/partial pressure in vasculature)?
80mmHg
What is the PaO2/FiO2 ratio in the vented patient?
Goal of 400-500
What is the calculation for Alveolar-arterial gradient?
2.5+0.21 (RA) x AGE
What is the Alveolar-aterial gradient?
O2 in the alveoli (PAO2)
VERSUS
O2 dissolved in the plasma (PaO2)
The Alveolar-arterial gradient increases with
An increase in FiO2
What does the oxyhemoglobin Dissociation Curve tell us?
The correlation between saturated HGB with partial pressure
What causes a LEFT shift on the oxyhemoglobin dissociation curve?
LOW temp/DPG
LESS O2 delivery to TISSUES
ELEVATED pH & Affinity (O2)
FETAL
“Meth” “LEFT”
What causes a RIGHT shift on the oxyhemoglobin dissociation curve?
REDUCED O2 affinity
INCREASED O2 delivery, DPG, H+ & Temp
More acidic
When HGB has a high affinity for O2
It will hold on to it
Hypoxemia is low O2 in the
Blood
Hypoxia is low O2 in the
Tissues
Hypoventilation will cause what issues?
Increase in PaCO2 & PACO2
Decrease in PAO2 & diffusion
How can hypoxemia be corrected?
Small increases in FiO2
Ventilation is….
Oxygenation is….
Co2 out
O2 in
Examples of Low flow
NC
Simple face mask
Face tent
NRB
Examples of High Flow
HFNC
Venturi Mask
Neb
Non-invasive/invasive vent (mechanical)
What is the FiO2 & LPM of venturi & trach collar?
FiO2= 0.24-0.6
LPM= 2-15
What is the FiO2 & LPM of NC?
FiO2= 0.24-0.4
LPM= 1-6
What is the FiO2 & LPM of simple mask?
FiO2= 0.35-0.55
LPM= 5-10
What is the FiO2 & LPM of NRB?
FiO2= 0.80-0.95
LPM= 10-15
FiO2 will increase by what percent per liter of O2?
4%
NRB is ideal for
Severely hypoxic, but ventilating well
Venturi is good for
COPD
Pre-oxygenation is known as
Denitrogenation
When we pre-oxygenate, our reserved is increased by
1.5-4L
What is the 2nd biggest reservoir of O2 besides the plasma?
FRC, which is the lung volume held after exhalation
What is the targeted end tidal O2?
90%, but most likely 88-92%
Where should FiO2 be to prevent hyperoxia?
40-50%
Hyperoxia can cause
Pulmonary/CNS/Ocular toxicity
Pro-inflammatory & cytotoxic effects
Will an increase in FiO2 help a patient hemmoraging?
NO
In HOTN, 100% O2 will cause
A reduce in SV & CO through an increase in SVR
100% O2 in cardiac ischemia can increase
Coronary vasoconstriction
100% O2 in cerebral ischemia can cause
A decrease in CBF
What system controls the airway?
PSNS by affecting the size, gland activity & microvasculature
What receptors are on the airway smooth muscle?
Adrenergic & an abundance of Beta 2 receptors (postgang/cholinergic)
SNS has this effect on airway smooth muscle
Indirect control
The NANC has this influence on smooth muscle tone
Direct
The NANC has a role in
The inflammatory process
What cells cause bronchoconstriction?
Histamine
Prostaglandin D2 & F2
Leukotrienes C4, E4 & D4
Platelet activating factor
Bradykinin
What preganglionic and postganglionic receptors are involved in PSNS influence?
Vagus pregang
Cholinergic postgang
How does contraction occur in the airway smooth muscle when the PSNS system is activated?
Vagus pregang–> Cholinergic post gang–>
ACh–>M3–>Gq (stimulatory)
Phospholipase C–> Increased IP3
SR releases Ca+–>MLCK activated
Which C fibers cause bronchoconstriction?
Sub P
NKa
Calcitonin gene related peptide
Catecholamine release can
Bind Beta-2 receptors indirectly through the SNS
Beta 2 during SNS activation will
Inhibit the release of ACh by causing hyperpolarization and stimulating adenyl cyclase, which increases cAMP & causes smooth muscle relaxation
cAMP in the smooth muscle will cause
Relaxation
Beta 2 stimulated which G protein?
Gs, which increases cAMP, which also created hyperpolarization, leading to HYPOKALEMIA
In the NANC system, what is inhibitory & what is excitatory?
Inhibitory- Nitric Oxide & Vasoactive Intestinal Peptide
Excitatory- Sub P & NKa
M2 involves which G protein?
Gi, which inhibits adenyl cyclase, leading to NO increase in cAMP, causing constriction
Asthma will cause these changes
Hyper-irritability
Airway remodeling
Mucous
Hypertrophy
Angiogenesis
Decrease in diameter & airflow
Increase in resistance
What are the long term effects of Asthma?
Epithelial damage
Submucosal edema
Mucous secretion/plugging
Increase in vascular permeability
Vasoconstriction