CCRN- Respiratory Flashcards
ABGs table
ROME-
Respiratory Opposite pH/CO2 (carbon dioxide)
Metabolic Equal pH/HCO3 (bicarb, base)
Acidosis 7.35 < pH > 7.45 Alkalosis
Alkalosis 35 < Co2 > 45 Acidosis (control by lungs)
Acidosis 22 < HCO3 > 26 Alkalosis (control by kidneys)
- **If pH w/in range, it’s always compensated
- *If pH <7.35, it’s uncompensated acidosis (pt is blowing off CO2)
*when H+ concentration ↑, the pH ↓
Respiratory Acidosis causes
Drugs
cardiac arrest
muscles weakness (MG, ALS)
COPD (retain CO2)
Respiratory Alkalosis causes
Hypoxemia CNS disorders (b/c alkalosis ↓ ICP) Salicylate overdose Cirrhosis Sepsis
Metabolic Acidosis causes
Ketoacidosis Lactic acidosis (↓BP) GI Loss (diarrhea) Renal failure
Metabolic acidosis can be measured by anion gap:
–difference b/w positive and negative ions
–normal: 5-15 mEq/L
(Na+ + K+) - (Cl- + HCO3-)
Metabolic Alkalosis causes
Blood transfusions
»the sodium citrate in banked blood converts to bicarb in the liver
Hypokalemia GI Loss (gastric acid) Contraction alkalosis (too much lasix, fluid deficit)
Acute Respiratory Failure- Hypocapneic
↓O2 + normal CO2 or ↓CO2
Ventilation/perfusion imbalance
Causes: Pulm edema PE Aspiration PNA Asthma ARDS PNA (aerated tissue turns semi-solid and conducts noise well, fremitus present)
Presentation:
tachypneic, Accessory muscle use, tachy early, brady late, HTN or hypo, cyanosis, anxious, agitated
***V/Q mismatch:
happens when part of your lung receives oxygen without blood flow or blood flow without oxygen. This happens if you have an obstructed airway, such as when you’re choking, or if you have an obstructed blood vessel, such as a blood clot in your lung.
CPAP or BiPAP
Acute Respiratory Failure- Hypercapneic
↓O2 + ↑CO2
Respiratory mechanical performance, exhalation issue
Causes: Drug overdose (CNS depression) COPD CVA Spinal cord (ALS, GB, MG) ↑ ICP
Presentation:
shallow breathing, clear lungs or not, progressive ↓ LOC
BiPAP- FiO2 + IPAP assist ventilation + EPAP assists oxygenation
In what respiratory condition does SHUNTING occur and what is it?
ARDS
-blood goes from R side of heart thru pulmonary vessels and never came in contact w/ alveoli, so blood returns to the arterial circulation with unoxygenated
»essentially ARDS is a separation of alveoli from the blood supply –NO GAS EXCHANGE occurs
***refractory hypoxemia b/c no matter how much O2 given, the pt will NOT get better (FiO2 100% will do nothing)»_space;»> PT NEEDS PEEP (pressure) to open alveoli!! The pressure inside distends the alveoli so that it touches the vasculature and gas exchg occurs.
!!! Keep pts with ARDS dry, minimal fluids.
Early stage of ARDS is tachypnea, normal PAWP, Resp alkalosis
Late stage is hypercapnia
How does shock lead to ARDS?
Shock causes capillary beds in lungs to vasoconstrict which will make blood flow stagnant, the epithelial wall is damaged then leaks and separates alveoli from the vessel d/t the fluid leakage into the space —lead to ARDS and NEED FOR PEEP!
How is Tidal volume set?
8-10ml/kg or about 2x normal TV
PaO2 vs PaCO2
PaO2 provides information on the oxygenation status, is a measurement of oxygen in arterial blood. It shows how well oxygen is able to move from the lungs to the blood (the PaO2 “sensors” in aortic arch–this is secondary control- if ↓ PaO2 sensed (hypoxemia), then ventilation stimulated (pt has increased rate and/or depth of breathing)
PaCO2 offers information on the ventilation status (chronic or acute respiratory failure).
PaCO2 is affected by hyperventilation (rapid or deep breathing), hypoventilation (slow or shallow breathing), and acid-base status.
Systemic artery:
PaCO2 = 40
PaO2 = 100
SaO2 = 99%
PaO2 vs SaO2
PaO2 is the pressure exerted by O2 on the arterial wall. SaO2 is the percentage of hemoglobin binding sites that are occupied with O2. This is the main difference between PaO2 and SaO2
What does a decrease in pH stimulate?
A ↓pH is acidosis, primarily ventilation stimulated by brain stem with increased rate and/or depth of breathing
What is minute ventilation?
TV x RR
normal is 4L/min
An ↑ in minute ventilation = ↑ WOB
What increases alveoli dead space?
PE
-a clot means no blood flow past alveoli in that area of pulm circulation
Ventilation vs Perfusion
Treatment if an issue?
(V) ventilation: air into and out of lungs
(Q) perfusion: mvmt of blood thru pulm capillaries
Normal V/Q ratio: 0.8 ratio =
4L ventilation/min
————————–
5L perfusion/min
***V/Q mismatch:
happens when part of your lung receives oxygen without blood flow or blood flow without oxygen. This happens if you have an obstructed airway, such as when you’re choking, or if you have an obstructed blood vessel, such as a blood clot in your lung.
Seen with pneumonia, PE
Tx of mismatch»_space; give O2, then treat underlying problem
If a patient has a large R lung PNA, how should the pt lay?
GOOD LUNG DOWN! Lay on left side.
Otherwise all the blood goes to the bad lung and pt may become hypoxemic
Note: when pt laying supine, all blood is posterior.