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CA final exam
Question | Answer |
---|---|
What two electrochemical o2 analyzers are good for basic fio2 monitoring? | clark electrode and galvanic cell |
Where can blood gas samples be taken from? | peripheral artery, indwelling catheter, capillary sampling |
What is considered the gold standard of gas exchange analysis? | ABGs |
why is the radial artery the preferred site for arterial blood sampling? | near the surface, easy to palpate and stabilize, ulnar artery gives good collateral circulation, not near any large veins, relatively pain free |
what are the indications for ABGs? | need to evaluate ventilation, acid base, oxygenation, status and oxygen carrying capacity of blood; need to assess the patient's response to therapy and/or diagnostic tests; need to monitor severity and progression of a documented disease process |
sampling of blood errors can be caused by: | air in sample, venous admixture, excess anticoagulant, metabolic effects |
The sample should be analyzed within | 15 min |
How long to do you need to give a critically ill or COPD patient to return to a steady state? | 30 min |
How long do you need to give a normal patient to return to steady state? | 15 min |
what are hazards and complications of ABGs? | Bleeding, hematoma,Infection,air/blood embolism,Arterial spasm, occlusion, vessel damage.Ischemia distal to sample site,Necrosis distal to sample site |
What are the contraindications of ABGs? | Inadequate collateral circulation,Never sample from a lesion or surgical shunt,Femoral samples outside a hospital setting,Prolonged anticoagulation, inadequate clotting mechanism. |
what are examples of noninvasive monitoring? | pulse oximetry, capnometry, and transcutaneous measurements |
what are pulse oximetry? | measurement of blood hemoglobin saturations. measures the light absorbed and transmitted by a substance and scientists can identify presence and concentration |
whjat does pulse oximetry use to measure? | photoplethysmography |
what two problems come with use of pulse oximetry? | technological problems (motion artifact, reading dark skin or through nail polish) and clinical interpretation (forgetting oxy hb curve) |
A false high reading on the pulse oximeter may be caused by | Hbco, MetHb, dark skin tone, dark nail polish, ambient light |
a false low reading on the pulse oximeter may be caused by | methb, anemia, vascular dye, MRI, electrocautery |
transcutaneous monitoring is best for what patients | neonatal/pediatric patients |
How do transcutaneous monitors work? | the device arterializes the underlying blood by heating the skin. warming also inc the permeability of skin to o2 and co2. it provides continous, noninvasive estimates of arterial po2 and pco2 through surface skin sensor |
what is capnometry? | measurement of co2 in respiratory gases |
how do co2 analyzers work? | measure absorption of infrared light after co2 absorbs it |
what are capnometers (co2 analyzers) good for? | detecting v/q imbalance |
what is capnometers best used for? | steady states like anesthesia, best used when both ventilation and perfusion are present |
How would you instruct a patient to perform an IC measurement? | measured directly from a spirogram. the patient is asked to inhale maximally from the resting FRC at the end of a normal effortless exhalation. |
How much does a patient need to inhale for an FVC maneuver? | the patient should inhale rapidly and completely to TLC from the resting FRC level. then there should be a forced exhalation begins right after- all of FVC must be exhaled (6 secs worth) |
How much of breath should be exhaled in first second? | 80% |
When looking at FVC curves, what is notable about obstructive diseases? | they produce flattened slopes and smaller FEV1 |
in obstructive lung diseases, what are the only capacity figures that will go up? | RV, VT, FRC, TLC |
how does helium dilution work? | Known volume and concentration of helium is introduced to the circuit. Patient breathes the gas mixture from ERV (start point) for about 2-5” until equilibration occurs. |
How long may helium dilution take on obstructed patients? | Severely obstructed may take 20” to equilibrate. |
how does nitrogen washout work? | Patient breathes 100% O2 for a period of time until exhaled N2 reaches 2.5%. Normally N2 is at 78%. Generally takes 2-5 minute to breath out all nitrogen, with the severely obstructed taking up to 20” or never completely “washing out”. |
how does plethysmography work? | Shutter valve opens and closes at specific intervals, allowing pressure and volume changes to be recorded. The patient “pants”. applies boyles law. thoracic gas volume is calculated |
what is DLCO (Diffusing Capacity using Carbon Monoxide)? | measurement of Transfer rate across the alveolar capillary membrane., works by breathing in CO |
who will have erroneous results on DLCO tests? | smokers or people who smoked that day |
what is the normal value of DLCO? | 40ml/min/mmHg |
what does a DLCO value less than 40 indicate? | indicative of restrictive processes such as: emphysema, fibrosis, or low lung volumes. |
during a bronchodilator study, what happens? | Spirometry is done then a BD is given.Spirometry is repeated. Look for changes in FEV1 of 15% and 200ml increase in volume. This is called reversibility. |
what does reversibility of the airway obstruction indicate? | effective therapy |
what does bronchial provocation entail? | Irritate the airway with exercise, cold air, or histamine. Looking for bronchospasm and obstruction in spiromerty. |
a positive response to saline is defined as | Decrease of 10% during FVC- means is hyper responsive airway. |
a positive response to methacholine is defined as | FVC repeated until a maximum drop of 20% in FEV1 is recorded. |
normal amt of impairment is | 80-120% obstruction |
what is GOLD Stage I: | Mild COPD FEV1/FVC < 70% FEV1 80% predicted With or without chronic symptoms (cough, sputum production) |
what is GOLD moderate stage? | COPD FEV1/FVC < 70% 30% FEV1 < 80% predicted (IIA: 50% FEV1 < 80% predicted) (IIB: 30% FEV1 < 50% predicted) With or without chronic symptoms (cough, sputum production, dyspnea)III: |
what is GOLD severe stage? | COPD FEV1/FVC < 70% FEV1 < 30% predicted, or the presence of respiratory failure, or clinical signs of right heart failure* Respiratory failure: PaO2 < 8.0 kPa (60 mm Hg) with or without PaCO2 > 6.7 kPa (50 mm Hg) while breathing air at sea level. |
When do we get xrays for sure? | Intubation Sudden change in patient condition-eg drop in saturation, change in level of dyspnea, chest pain, any sudden acute changes that are strange for that patient When we insert something like a central line or catheter |
What monitoring devices do you want to use for a patient who just survived a house fire? | ABG-to check for carbon monoxide-run blood through coaximter |