Oxygenation & Hypoxemia Flashcards
The goal is to maintain Oxygen saturation above
94%
what is the arterial O2 tension (PaO2)
whats dissolved in the plasma & partial pressure
What is the goal of PaO2?
Above 88mmHg
What is the definition of A-a
The Big A- Alveolar
The small a- arterial
How can the Alveolar-arterial oxygen gradient be increased?
by increasing FiO2
An increase in Oxygen affinity, reduced oxygen delivery to tissues, alkalosis, low temperature, low DPG, and fetal Hb, causes a shift to the
LEFT
An increase in oxygen delivery to tissues, reduced oxygen affinity, acidosis, increase in temperature and DPG, causes a shift to the
RIGHT
Definition of Hypoxemia
Abnormally low O2 in the blood
General-whole body
Tissue-localized/regional
How is hypoventilation corrected?
Increasing FiO2
What happens with hypoventilation?
PaCO2 & PACO2 increase
PAO2 decreases
Examples of LOW FLOW O2
Nasal Cannula, Simple Face Mask, Face Tent, Non-Rebreather Mask
Examples of HIGH FLOW O2
High Flow Nasal Cannula, Venturi Mask, Nebulizer, Non-invasive and Invasive Mechanical Ventilation
FiO2 delivery of the following Low Flow:
NC-
Simple Mask-
NRB-
NC-0.24-0.4
Simple Mask-0.35-0.55
NRB-0.80-0.95
FiO2 delivery of the following High Flow:
Venturi-
Trach Collar-
Venturi-0.24-0.6
Trach Collar- (same)
LPM:
NC-
Venturi-
Trach Collar-
Simple-
Non-rebreather
NC- 0.24-0.4
Venturi- 0.24-0.6
Trach Collar- (“ “)
Simple- 0.35-0.55
Non-rebreather- 0.80-0.95
Preoxygenation replaces ____ with _____ being the second biggest resivoir of O2 besides the plasma
Replaces Nitrogen
FRC (Functional Residual Capacity)-denitrogenation
Target end-tidal ETO2
90%
Risk of delivering high O2 fraction
Hyperoxia
Hypotension (cause reduced SV & CO through increased SVR)
Cardiac & Cerebral ischemia (increased coronary constriction & decreased CBF)
The airway is controlled by what autonomic system?
Parasympathetic (VAGUS nerve primary)
Catecholamines binding to BETA-2 receptors in the airway smooth muscle will cause
BronchoDILATION
Sympathetic NS and NANC control in airway
SNS-no DIRECT control
NANC-direct influence on smooth muscle (relaxation) and role in inflammatory response
PSNS releases ______ which activates ______receptors, causing. vaso________
ACH; M3; constriction
Activation of G____protein and ____________ & and an increase in _______ causes__________
Q; Phospholipase C; IP3; vasoconstriction
What are some bronchoconstricting mediators released by the PSNS?
Bradykinin
Prostaglandins
Leukotrienes
Sub P
NK-A
BETA-2 receptors on postganglionic cholinergic nerve causes
HYPER polarization & reduced ACh release
BETA-2 recepotrs on airway smooth muscle calls cause
stimulation of adenyl cyclase which INCREASES cAMP, HYPERpolarizatioon, and ultimately smooth muscle relaxation
HYPERpolarization is due to
loss of potassium
Nitric OXide and Vasoactive Intestinal Peptide (VIP) are
Inhibitory
Substance P and NK-A are
Stimulatory
Asthma causes these changes in the respiratory system
Inflammation
Irritability
Remodeling
Constriction
Fibrosis
Mucous production
Smooth muscle hypertrophy
Angiogenesis
Increased vascular permeability
Asthma causes ________airway resistance
Increased
COPD is often ________
Irreversible
Emphysema causes a loss of _________,__________, &____________
surface area, elastic recoil, & loss of structural integrity
What can cause bronchoconstriction in the intra-op area
Abx, airway manipulation, surgical stimulation, NMB, histamine release(morphine)
What are some assessment observations that will lead to a diagnosis of bronchospasm?
Increased Peak Airway Pressures, Reduced TV, difficulty bagging, sharkfin capnography, changes in SaO2 and PaCO2, wheezing
Wheezing is
A POOR indicator of degree of airway obstruction
