MCRT- ABG class

Description:	MCRT- ABG class
Category:	Respiratory Therapy
Created by:	smiddleton on 2009-06-08

Question	Answer
Ideal Gas Law	PV = nRT
Boyles Law	P1 x V1 = P2 x V2; If Temperature remains constant, pressure will vary inversely with volume;TB
Charles Law	V1 / T1 = V2 / T2;If pressure is held constant, volume and temperature will vary directly;CP
Gay-Lussac’s Law	P1 / T1 = P2 / T2;If volume is held constant, pressure and temperature will vary directly;Vitamin G.
Dalton’s Law of Partial Pressure	1)P1 + P2 + P3 ... = PTotal 2)The gases act independently of each other 3) Water vapor pressure does not follow Dalton’s law 4)% = Pp / Pbar.
Atmospheric Pressures at Sea Level	Oxygen 159 torr 21%; Nitrogen 600 torr 79%; Others 1 torr 0.1%
Alveolar Gas at Sea Level	Oxygen 13.3% or 101 torr; Nitrogen 75.2% or 572 torr; Carbon dioxide 5.3% or 40 torr; Water vapor 6.2% or 47 torr
Humidity	When in vapor form, water exerts a partial pressure
BTPS	BT = body temperature (37 C); P = atm pressure to which the body is exposed; S = saturated with maximum water vapor (47 torr).
Partial Pressures at BTPS	Water vapor = 47 torr (100% saturated); CO2 = 40 torr; O2 = 101 torr; N2 =572 torr; Total pressure = 760
The partial pressure exerted by water in the gas form is directly related to……	Temperature
Diffusion	The constant random movement of gas molecules results in a net displacement from an area of higher concentration toward an area of lower concentration (passive movement).
Gas Solubility	When a gas molecule enters the liquid, it either exists as a gas (dissolved) or chemically combines with constituents of the liquid.
Henry’s Law	The amount of gas that can be dissolved in a liquid is proportional to the partial pressure of the gas to which the liquid is exposed
Graham’s Law	The rate of diffusion of a gas through a liquid is inversely related to the square root of the GMW of the gas.
Fick’s Law of Diffusion	the degree to which the gases can dissolve in the liquid depends of both the pressure gradient and the factors affecting diffusibility across the membrane; Thickness of the membrane; Cross-sectional area of the membrane
Different Types of Samples	Arterial Blood; Arterialized capillary blood; Mixed venous blood; Peripheral venous blood.
Arterialized Capillary Blood	Infants and small children; Deep puncture that produces free flowing blood; Heated;Can be correlated with arterial blood; Collected in a capillary tube.
Mixed Venous Blood	Final mixture of all venous blood; Pulmonary artery catheter required
Central venous blood can be drawn from....	Inferior vena cava; Superior vena cava; Right atrium
Peripheral Venous Blood	Veins run directly adjacent to artery; Values will vary from site to site; Not a substitute for Mixed Venous Blood.
2 Key Factorsfor the assessment of oxygenation	How effectively the arterial blood is oxygenated by the lungs; Blood circulation throughout the body
PaO2	Indicates how effectively oxygen is made available to the blood for transport to the tissues
Oxyhemoglobin (HbO2)	Functional hemoglobin that is actively carrying oxygen molecules
Reduced hemoglobin (R-Hb)	Hemoglobin that has released its oxygen
Methemoglobin (MetHb)	Not capable of carrying oxygen; Reduced the capacity of blood to carry oxygen; Brown color; %MetHb
Carboxyhemoglobin	Oxygen sites occupied by Carbon Monoxide; %HbCO; Larger values indicate less oxygen delivery; Victim has a healthy color; Combines 210 times more easily than oxygen.
Total Hemoglobin	Cumulative total value for all forms; HbO2 + R-Hb + MetHb + HbCO; More Hb = more carrying capacity
SaO2	(Content/capacity) x 100; Calculated by some ABG equipment; Measured directly by CO-oximetry
P50	Partial pressure of oxygen that creates SaO2 of 50%
Blood Oxygen Content (CaO2),Arterial Content	(Hb x 1.34).SaO2 + (PaO2 x .003)
Typical value of CaO2	20 vol%
CvO2	(Hg x 1.34).SvO2+(PvO2 x .003)
Typical value for CvO2	15 vol%
C(a-v)O2, a-v difference	Typical value 5%; CaO2 – CvO2; 20 vol% - 15 vol%
Transportation of Oxygen	TO2=(CaO2 x 10) x Cardiac output; 10 converts everything to Liters; Units are ml O2/min delivered to tissues.
Qsp/Qt	Measure of physiologic shunting (Qsp) of pulmonary blood as a fraction of cardiac output (Qt)
True Shunting	Result of pulmonary blood flow where there is no ventilation
Shunt Effect	Pulmonary blood flow with limited amount of ventilationGas exchange is incomplete.
Formula for shunt	(CcO2 – CaO2)/(CcO2 – CvO2)
PAO2	[(Patm – 47).FiO2] – (PaCO2 x 1.25)
Oxygen Extraction Ratio	C(a-v)O2 / CaO2
Oxygen Consumption (VO2)	(C(a-v)O2 x 10) x QT
Ventilation	PaCO2 – single best indicator of ventilation; CO2 diffuses 20 time easier than O2; Significant reciprocal relationship between PaCO2 and alveolar ventilation; If VA increased, then PaCO2 decreases.
pH	Provides a direct statement of the acid/base balance; Alkalosis- A pH value greater than normal; Acidosis-A pH value less than normal
3 ways to make the pH more acidic	Increase acid; Decrease base; Combination (mixed)
3 ways to make the pH more alkalotic	Increase base; Decrease acid;Combination (mixed)
The respiratory contribution is ...	PaCO2; The level of ventilation plays a significant role in maintaining pH
The metabolic contribution is ...	HCO3; Renal function plays a significant role in maintaining pH.
Base Excess (BE)	Provides additional information quantitating the metabolic contribution to pH; Takes into account the buffering systems for pH; Typical value: ± 2; BE and HCO3 follow the same trendsAre effected by the same influences
Equipment for Blood Sampling/Puncture	Antiseptic agent for skin; Sampling needle/syringe; Heparin; Vented; Sterile pad for holding pressure; Equipment is the same regardless of puncture site
Equipment for Blood Sampling/Art Line	Two (2) needless syringes; 1- Remove flush solution from art line; 5 or 10 ml syringe (regular); 1- ABG syringe
Vamp Blood Conservation	Arterial line; Expandable reservoir; No blood waste
Equipment for Arterialized Capillary Blood	Site warmer to increase local perfusion; Antiseptic agent; Lancet for skin puncture; Sterile pad; Capillary tube (heparinized)
3 things measured by ABG Machine	pH, PaCO2, PaO2
oxygen electrode	Clark electrode
CO2 electrode	Serveringhaus electrode
pH electrode	Sanz electrode
If the patient does not have a normal temperature which way do the ABG values move?	In the same direction as the patient temperature
Machine Maintenance	Flush after each analysis; Calibration; Proficiency Testing
Modified Allen’s Test	Checks for collateral circulation; Color should return within 15 seconds; Positive result is good! You will need to explain the technique.
ABG puncture technique	Aseptic technique; Straight in, straight out; Flash of blood in hub of needle; If blood flow stops you have most likely punctured completely through the arteryHold pressure on wound site; Anticoagulation therapy; Anticoagulation blood disorder
Handling blood after puncture	Remove all air bubbles from sample; PO2 values will move toward 150; CO2 values will move toward 0; Label syringe with patient information; Place solution on Ice; Metabolism continues; Analyze ASAP.
Other normal ABG vallues	Hb 12 – 16; CaO2 ~20; %MetHb <1.5%; %HbCO .5 – 2%
Mixed venous values	pH 7.4; PvCO2 45; PvO2 40; HCO3 24; SvO2 75%; CvO2~15
Intrepretations	Intrepretations
Acute on Chronic	Refers to an Acute condition (hyperventilation/hypoventilation) with an underlying chronic (CO2 retainer) problem
Baseline CO2 retainer values	pH 7.4 (normal); CO2 55 (or higher); O2 55; HCO3 30 (or higher)
Describe how hypoxemia can affect the acid-base balance	it can cause lactic acidosis
pH	-log[H]
Describe the technique for collecting aarterialized (capillary) blood sample.	1) Warm the site. 2) Lance the skin. 3) Collect blood into the capillary tube. 4) Hold pressure on site.