I. PATIENT DATA
EVALUATION AND RECOMMENDATIONS
B. Collect and Evaluate Additional Pertinent Clinical Information
7. Perform procedures including
a.) 12-lead ECG
The ECG is a graphic display of current generated by the heart at the surface of the body. It depicts depolarization and repolarization of the atria and ventricles. Its purpose is to measure the electrical activity of the heart.
This section of the exam will test your understanding of ECG machine leads and electrodes and their placement. Electrodes are placed on the arms and legs and on the chest, around the heart. The ECG machine adjusts with electrodes will be positive and which one(s) will be negative. When the impulse of the heart moves towards the positive electrode, an upper deflection is made on the ECG paper. Movement of the impulse away from the positive electrode produces a downward deflection. There are 12 leads used and six precordial chest leads. This section on the CRT includes recall questions only and on the RRT will be on its application.
There may be questions regarding the machinery or where the leads go, but I think it is more likely you will seem something like: A man walks into the ER complaining of chest pain and is experiencing extreme diaphoresis. What is the first thing you do?
Here you might find hook him up to a 12 lead ECG because you suspect an acute MI.
b.) Pulse oximetry. On the CRT you will be asked recall and application questions and on the RRT analysis questions.
Pulse oximetry uses a pulse oximeter to measure heart rate and oxygen saturation. The unit uses 2 wavelengths of light, red and infrared. The absorption of light by oxyhemoglobin and reduced hemoglobin is compared. This measures oxyhemoglobin saturation. The probe us applied to one of the patients fingers (index usually) or if the perfusion is not good or a good reading is not achieved, the patients ear can be used. The bridge of the nose is also a possibility. If there is a drastic change in the oxygenation reading, the first thing to check is the probe. It frequently comes loose or does not set properly to get a good reading.
One of the often repeated questions I have seen here is What is the least likely piece of equipment you would need to evaluate a patient with carbon monoxide poisoning. That of course is the pulse ox.
Also, you might see something about the saturation on the pulse ox drops suddenly, what is the first thing you do? That of course is to check the probe.
c.) Tidal volume, minute volume, peak flow, vital capacity
On the CRT exam you will be asked recall and application questions. On the RRT you will be asked analysis questions.
The tidal volume is the volume of gas moved in OR out of the lungs in a normal resting breath. Use a respirometer to measure. The best way is to have the patient exhale into the respirometer for one minute and divide the minute total by how many times the patient breathed during that minute.
Also, If the patient cannot spontaneously inhale a sufficient tidal volume, the patient will have to breathe at a faster rate to obtain a sufficient minute volume. The patient may need help to do this and then may need a ventilator.
The minute volume is the tidal volume multiplied by the breathing rate of the patient for one minute. If the pt has a Vt of 500 and is breathing 8 times a minute the calculation would be 500 X 8 = 4000ml/min or 4 L/min. Can also be done by having the patient exhale into a respirometer for one minute and take the total.
If the minute volume is too low, the patient cannot move enough air to provide proper ventilation. If it is too high, it is likely the patient will not be able to sustain the amount of work to provide the large minute volume over an extended period of time.
Peak flow is actually the peak expiratory flow rate. It normally occurs during the early part of exhalation. Normal peak flows range from 400 to 600 L/min. for young healthy men and 300 to 500 L/min. for young healthy women. Decreased Peak flows indicate a large airway obstruction. All volumes measured with a peak flow meter need to be converted to body temperature and the procedure is patient effort dependent.
Vital capacity is the maximum volume of gas that can be exhaled after a maximal inspiration. (ERV + Vt + IRV). Patient is instructed to take a maximal inspiration followed by a maximal exhalation without force.
VC will provide important volumes used to measure restrictive disease. The vital capacity can be found by adding the inspiratory reserve volume + tidal volume + expiratory reserve volume. Decreased volumes indicate restrictive lung disease. The vital capacity is the BEST INDICATOR of restrictive lung disease. You might also see a question asking what is the best bedside test for myasthenia gravis, and that of course is VC
d.) Bedside spirometry (e.g. FVC, FEV1)
Bedside spirometry includes the measurement of forced vital capacity, forced expired volume in one second (FEV1), percent of vital capacity expired in one second (FEV1%) and forced expiratory flowrate between 25% and 75% of vital capacity (FEF 25-75). The patient's actual values are reported along with predicted values and the percentage of predicted values.
Bedside spirometry measures vital capacity (VC), inspiratory and expiratory volumes, total lung capacity, and simple dynamic measurements such as forced expiratory volumes (FEV) versus time. The patient's measurements are compared with predicted measurements based on the patient's age, sex, and size. Spirometry reliably detects severe restrictive lung disease and also chronic obstructive pulmonary disease (COPD). Normally, the FEV 1 (FEV in 1 second) is 80 percent of predicted; values below 50 percent usually require further evaluation that includes laboratory pulmonary function tests, ventilation-perfusion scans, and pulmonary consultation. Bedside testing may underestimate the patient's best FEV 1 or VC.
e.) Arterial sampling percutaneous or line. On the CRT you will be asked recall and application questions. On the RRT analysis questions will be asked.
On the exam you might get questions that include ABG calculations. Examples would include finding CaO2, PAO2, A-aDO2, CvO2, C(a-v)O2. You will need to know what equipment is used. Examples would include ABG kit, blood gas analyzer or transcutaneous monitoring.. The RT needs to wash hands thoroughly and then dry them without contacting anything that might cause contamination. Then the RT will apply gloves, open the kit, palpate the radial pulse and find a spot he/she thinks will be a good stick and then rub that spot with an alcohol swab. Approach the radial artery with the bevel of the needle up and at 45 degrees. After the stick you want to compress the wound for at least 5 minutes or however long it takes to stop bleeding.
An arterial line might already be in place on the patient. (usually in the radial artery). The procedure includes withdrawing fluid and blood from tubing before sampling by means of a stopcock in which a discard syringe is used to aspirate the fluid/blood mixture before obtaining the blood sample. Then you would draw the arterial blood gas sample with a preheparinized syringe.
f.) blood gas analysis. On the CRT you will get recall and application question and on the RRT you will get analysis questions.
Once blood is drawn, it should be put on ice. The syringe needs to be properly labeled so the right analysis is done with the correct patient. The blood is then taken as soon as possible to the lab to be analyzed by the ABG analyzer. The RT needs to wear gloves while handling the sample. After the blood is drawn by the analyzer, the RT should re-cap the sample syringe and put it back on ice in case there is a problem with the machine or anything unforeseen that might give a false reading. After the analysis is run and everything looks as if it was all done properly and the results are accepted as true, the Rt can then put the needle an syringe in a sharps container, take off the gloves and wash hands thoroughly.
e.) Blood gas/hemoximetry analysis. CRT = recall, application, RRT = analysis
You will need to know how to interpret and manage the results of the blood gas sample.
Normal measurements:
PCO2 = 35 to 45 mmHg
PO2 = 80 to 100 mmHg
pH = 7.35 to 7.45
SO2 = 95 to 100%
HCO3 = 22 to 26 mEq/L
BE =
HB = 12 to 16 gm
CaO2\CvO2 = 17 to 21 Vol%
As for meanings of results for previously normal lungs
PaCO2: above 45 the patient is not ventilating enough. Below 35, the patient is ventilating too much.
PaO2 below 80 shows hypoxemia. This can be due to poor ventilation, V/Q mismatch or shunting. PaO2 over 100 is overoxygenating. You would decrease the FiO2, PEEP or CPAP.
pH below 7.35 is uncompensated acidosis and above 7.45 is uncompensated alkalosis
A respiratory acidosis or alkalosis is the diagnosis when the pH is abnormal due to a change in the PCO2. A metabolic acidosis or alkalosis is the diagnosis when the pH is abnormal due to a change in the HCO3. A partial compensation occurs when the pH is out of the normal range and where both CO2 and HCO3 are changing in the same direction. A mixed or combined respiratory and metabolic imbalance occurs when both CO2 and HCO3 contribute to the problem. An example would be when the PCO2 is low and the HCO3 is high
Formulas include:
CaO2 = (Hg
This is the best measurement of O2 delivered or best index of O2 transport
PAO2 = (PB PH2O)FiO2 PaCO2 x 1.25
This calculates the pressure of oxygen (PO2) in the alveoli
A-aDO2 = PAO2 PaO2
This measures the difference between alveolar and arterial PO2
CvO2 = (Hg
This is the total amount of oxygen carried in mixed venous blood
C(a-v)O2 = CaO2 CvO2
This measures the oxygen consumption in the tissues.
The three primary sites for obtaining an ABG are the radial, brachial and femoral arteries. The site of choice is the radial artery, followed by the brachial and the femoral is the last choice.
g.) Lung mechanics (e.g. MIP, MEP, pulmonary compliance, plateau pressure, airway resistance). The CRT will ask recall and application questions, the RRT will ask analysis questions.
MIP (maximal inspiratory pressure) measure respiratory muscle strength. It is also called NIF or negative inspiratory force. This test is done by having the patient breathe out as far as they can and you occlude there inspiration routes. As the patient tries to inhale a pressure level is reached. You take the highest reading with a period of time not to exceed 15 to 20 seconds.
MEP measure maximal expiratory pressure.
Pulmonary compliance measures the ease of distention of the lungs and is inversely related to elastance. There are two measurements we look at with compliance. The static and dynamic compliance.
Static compliance = tidal volume / (Plateau pressure PEEP)
Dynamic compliance = tidal volume / (Peak insp. Pressure PEEP)
Plateau pressure is affected only by compliance.
Airway resistance equals the difference between the peak and plateau pressure.
Plateau pressure is affected only by compliance.
Airway resistance
RAW equals the difference between the peak and plateau pressure. The wider the two are apart the more airway resistance there is.
Its a good bet that you will see questions asking you to figure static or dynamic compliance. You need to know the formula.
h.) Ventilator pressure-volume and flow volume loops. On the CRT you will receive recall and application questions and on the RRT analysis questions.
There are 2 types of positive pressure ventilators, volume and pressure cycled.
With a volume cycled ventilator, pressure is applied to the airways until a preset volume is delivered. Minute volume will remain constant to provide stable blood gases. Pressure will increase or decrease with changes in compliance and/or airway resistance.
With a pressure cycled ventilator, ventilation is adjusted by increasing or decreasing the pressure limit. They are normally pneumatically powered (50psi) and will apply positive pressure to the airways until a preset pressure limit is reached. Although peak pressures will remain constant, the volumes will change as the lung compliance and/or airway resistance changes.
Flow volume loops are waveforms that plow 2 of the primary ventilator parameters against each other. They can be helpful in assessing the work of breathing, leaks, overdistension, compliance, resistance and patient ventilator synchrony. The optimum PIP, Vt and PEEP levels can also be set using the flow volume loop.
i.) Apnea monitoring CRT = recall, RRT = application and analysis
Apnea patients will most often complain of daytime sleepiness and insomnia at night.
Observation in a sleep lab (somnopneumograph, polysomnography) will confirm the diagnosis and assess the severity.
Sleep studies use chest motion detectors to measure the respiratory effort, flow detectors to measure nasal flow and oximetry to measure oxygen desaturation during apneic periods.
There are 3 kinds of apnea.
Central which is apnea due to a loss of ventilation effort.
Obstructive which is apnea due to a blockage of the upper airway.
Mixed which is a combination of central and obstructive apnea.
The patients will most often complain of daytime sleepiness and insomnia at night.
Observation in a sleep lab (somnopneumograph, polysomnography) will confirm the diagnosis and assess the severity.
j.) Overnight pulse oximetry CRT = recall, RRt = application and analysis.
This is used mainly for adult patients with sleep disorders.
k.) Tracheal tube cuff pressure and/or volume CRT = recall, RRt = application
Remember high pressure bad, high volume good when used. However, the cuff should be kept deflated unless the patient is eating or is on positive pressure ventilation.
Cuff pressures should be around 20mmHg or 25cmH2O. Be aware of the units used on the test. The pressures should not be higher than the afore mentioned pressures.
l.) Tracheal intubation CRT = recall and application, RRT = analysis
Tracheal intubation is mainly for long term vent patients. However, it can be used for patients with problems with the upper airways or very severe facial trauma.
A tracheal intubated patient is easier to stabilize, suction and is better tolerated. Some have removable cannulas which can be cleaned by brushing or rinsing with hydrogen peroxide. The patient is able to eat, and even speak with fenestrated tubes. There are fewer hazards and minimal airway resistance. The tube should not be changed more than once a week unless there is an obstruction, the tube is too small or the cuff is punctured.
m.) Pulmonary function studies (e.g. flows, volumes, diffusion studies, pre-post bronchodilators) CRT = recall and application, the RRT = analysis
PFTs are indicated any time that an assessment of the respiratory system is required or desired. Specifically, PFTs will evaluate the presence of lung disease, extent of abnormal lung function, amount of disability due to the dysfunction, progression of the disease, nature of the dysfunction or type of disease, and course of therapy for the dysfunction.
Low flows = obstruction
Low volumes = restriction
Diffusion studies include Nitrogen washout and helium mixture
Pre and Post bronchodilator = if 20% or better improvement, then indications are that the obstructive problem is reversible.
n.) Auto-PEEP detection.. Only on the RRT and questions can be recall, application and analysis.
Auto-PEEP is developed at the lung parenchymal level as a result of air flow limitations
(COPD) or insufficient expiratory time (rapid rates) It is not measurable on a ventilator unless the expiratory hold is applied at the moment the next positive pressure breath is to be delivered and that breath delivery is delayed.
8. Interpret procedure results including:
a.) Transcutaneous O2/CO2 monitoring RRT only and in all there categories, recall, application and analysis.
With the use of polarographic electrodes this method allows for a continuous, non-invasive PO2 and PCO2 measurement with the electrodes place on the skin instead of a single measurement with a blood sample.
Heating the skin around the electrodes to 43 to 45 degrees celcius improves the capillary blood flow and enhances gas movement thru the skin. Good perfusion is a must, so the electrode has to be placed on the skin in an area where good perfusion exists. The electrode site needs to be changed every 4 hours or so to keep from burning the skin. Calibration is done on room air and with a zeroing solution.
b.) Capnography measures carbon dioxide content using infrared absorption. Once the capnography is set up, a blood gas is taken to correlate the values. Normally the PetCO2 will read lower than the arterial PCO2. PaCO2 usually = around 40mmHg and PetCO2 usually runs around 30 mmHg. The sensor should be placed proximal to the patients airway connection (at the endotracheal tube). An increase in the capnography would indicate a decrease in ventilation. (ventilatory failure) A decrease in the capnography would indicate an increase in ventilation or a decreased perfusion (deadspace disease, pulmonary embolism, hypovolemia). A reading of zero or low would mean you should reconnect the patient to the ventilator.
C.
Recommended Procedures to Obtain Additional Data Including: RRT = application
and analysis
1. Radiographic and other imaging.
This section includes radiographs and other imaging devices used in diagnosis as well as confirmation of ET tube placement.
One thing the candidate needs to remember about imaging is that is it not something to be done when you have 5 minutes to assess the patient.
A. Proper artificial airway placement
1. How should the tip of the ET tube be positioned when viewed on an Xray?
Below the vocal chords and no closer than 2cm above the carina, approximately the same level of the aortic knob.
2. What will quickly determine adequate ventilation before a chest Xray is done?
Observation and auscultation
B. Anatomical Landmarks - CXR
1. When are the costophrenic angles obliterated?
Angle made by the outer curve of the diaphragm and the chest wall. These angles are obliterated by pleural effusions
2. When is the diaphragm flattened?
Normally dome shaped, flattened with COPD, Left or right hemidiaphragms may shift downward with left or
Right pneumo thorax, appearing flattened on one side.
C. Positions
1. Describe each of the following positions for CXRs
a. Lateral position Projection from either side. Lateral neck xray for determining Epiglottitis (supraglottic)
Croup (subglottic), foreign bodies (presence or position)
b. Lateral decubitus Pt lying on the affected side. Valuable for detecting small pleural effusions.
D. Describe the appearance of a normal CXR
1. Both hemidiaphragms are rounded (dome shaped)
2. The right hemidiaphragm is slightly higher than left
3. The right hemidiaphragm is at the level of 6th anterior rib.
4. Trachea is midline, bilateral radiolucency, with sharp costophrenic angles.
E. Tube and Catheter Positions
1. Describe where each of the following should be located when positioned
properly.
a. Chest tubes should be located in the pleural space surrounding the lung.
b. Nasogastric and feeding tubes- should be positioned in the stomach and small bowel below diaphragm
c. Pulmonary artery catheter should appear in the right lower lung field.
d. Pacemaker should be normally positioned in the right ventricle
e. Central venous catheter placed in the right or left subclavian or jugular vein and should rest in the
Vena cava or right atrium of the heart.
F. Radiology Terminology and Interpretation
Description first then Diagnosis
1. Radiolucent dark pattern (air) Dx normal for lungs,
2. Radiodense - white pattern, (solid or fluid) normal for bones and organs
3. Infiltrate any ill-defined radiodensity, Dx. Atelectasis
4. Consolidation solid white area. Dx. Pneumonia/pleural effusion
5.
Hyperlucency extra pulmonary air.
6. Vascular markings lymphatics, vessels, lung tissue.. Dx. Increased in CHF absent in pneumo
7. Diffuse spread throughout, Dx. Atelectasis / pneumonia
8. Opaque fluid, solid. Dx. Consolidation
9. Bilateral on both sides
10. Unilateral on one side.
G. Diagnostic Descriptions and Interpretation
Description and diagnosis
1. Fluffy infiltrates diffuse whiteness. Dx. Pulmonary edema
2. Butterfly pattern infiltrate in shape of butterfly, Dx. Pulmonary edema
3. Patchy infiltrates scattered densities. Dx. Atelectasis
4. Platelike infiltrates thin-layered densities. Dx. Atelectasis
5.
Ground glass appearance reticulogranular
6. Honeycomb pattern - Reticulonodular Dx. ARDS/IRDS
7. Air bronchogram - DX. Pneumonia/edema
8. Peripheral Wedge-shaped infiltrate - DX Pulmonary embolus/infarction
9. Concave superior interface/border DX pleural effusion
10. Basilar infiltrates with meniscus DX pleural effusion
1. What is the main indication for a bronchography
By outlining the airways it will allow study of obstructing lesions and
bronchiectasis.
2. List 2 hazards of a bronchography
a. allergic reaction
b. impairment of respiratory state
B. Pulmonary ventilation/perfusion scans (V/Q scan)
1. Describe how this test is performed.
Radioisotope xenon gas is inhaled and the location of the gas is recorded
producing a photographic pattern of distribution throughout the lungs. Any
obstruction to airflow will allow little gas to enter the area
2. What does normal ventilation but abnormal perfusion indicate?
Pulmonary emboli
C. Magnetic Resonance Imaging (MRI)
1. What is the advantage of using MRI over conventional XRAY?
Has the ability to determine the precise position of tumors and the
involvement of surrounding structures.
2. What types of ventilators are used with MRI and why?
Fluidic non-electric, gas powered ventilators are used for pts requiring
mechanical ventilators because the magnetic fields would disrupt
electronic devices. Manual ventilators should have detachable
Non-rebreathing valves made of non-ferrous (non-metal) materials.
D. Computerized Tomography (CT)
1. What does the process of (CT) provide the practitioner with?
Provides a cross sectional view (slices) of body structures at multiple levels
2. With what types of pathologies would a (CT) be indicated?
Useful in detecting the presence of mediastinal mass, pleural and parenchymal masses and pulmonary
Nodules and lesions not visualized on CXR.