Ch 19 Analysis and Monitoring of Gas Exchange
What factors does not contributing to bias (systematic) errors during blood gas analysis? a. incorrect procedures b. statistical probability c. contaminated buffers d. component failure
b. statistical probability
What media are used to calibrate a blood gas analyzer's gas electrodes? a. standard pH buffer solutions b. blood-like control media c. precision mixtures of O2 and CO2 d. tonometered human blood samples
c. precision mixtures of O2 and CO2
What is the quality control procedure of analysis and reporting on externally provided control media with unknown values? a. automated calibration b. performance validation c. proficiency testing d. preventive maintenance
c. proficiency testing
What size needle would you recommend to obtain an ABG sample through percutaneous puncture of an infant? a. 18 gauge b. 20 gauge c. 22 gauge d. 25 gauge
d. 25 gauge
What should the transcutaneous blood gas electrode NOT be placed on? a. chest b. abdomen c. lower back d. thigh
d. thigh
What Centers for Disease Control and Prevention (CDC) barrier precautions would you use when obtaining an arterial blood gas (ABG) through percutaneous puncture? 1. gloves 2. protective eyewear 3. gown or apron
1 and 2
What are the purposes of a needle-capping device? 1. to isolate the sample from air exposure 2. to help prevent needlestick injuries 3. to hold the excess anticoagulant
1 and 2
You are monitoring a nurse acquiring a capillary blood sample from an infant. The nurse immediately punctures the infant's heel with a lancet and then squeezes the puncture site to increase the flow of blood. What mistakes has the nurse made while obtaining the capillary blood sample? 1. inadequate warming of the capillary bed. 2. squeezing of the puncture site. 3. puncture of the infant's heel. 4. use of a lancet.
1 and 2
You return to a patient's room 20 min after drawing an ABG. What should you check at this time? 1. puncture site for hematoma 2. adequacy of distal circulation 3. prothrombin or partial thromboplastin times
1 and 2
A mixed venous blood sample obtained from a pulmonary artery catheter sample has a PO2 of 85 mm Hg and a hemoglobin saturation of 95%. What is likely? 1. The pulmonary artery catheter balloon was not deflated. 2. The sample was drawn from the proximal, not distal port. 3. The blood sample was withdrawn too quickly.
1 and 3
Before a sample of capillary blood is taken, what should you do to the site? 1. warmed to 42° C for 10 minutes 2. squeezed lightly until blanched 3. cleaned with an antiseptic solution
1 and 3
To avoid thermal injury with transcutaneous blood gas monitor sensors, what should you do? 1. Carefully monitor the sensor temperature. 2. Apply hydrocortisone cream under the sensor. 3. Regularly rotate the sensor site.
1 and 3
What changes would occur if an arterial blood sample of a patient breathing room air were exposed to a large air bubble? 1. decreased PCO2 2. decreased pH 3. increased PO2
1 and 3
What indicates venous admixture during arterial puncture? 1. need to use syringe suction 2. dark-colored blood 3. small sample volumes
1 and 3
When analyzing a blood gas control sample, you notice that the result falls outside the 2 SD range. How could you verify that this was a random error (error of imprecision)? 1. Repeat the analysis on a different analyzer. 2. Compare the control to an actual patient sample. 3. Rerun the control sample a second time.
1 and 3
When inspecting an internal quality-control plot for a blood gas analyzer, you notice several data points sporadically appearing outside the 2 standard deviation (SD) range. This represents what type of analytic error? 1. random error 2. bias 3. imprecision 4. systematic error
1 and 3
While analyzing a blood gas control sample, you notice a trending of several PCO2 values above the 2 SD range over the last six control samples run. What corrective action would you consider at this time? 1. Check the function of the PCO2 electrode. 2. Rerun the control sample a second time. 3. Repair or replace any failed components.
1 and 3
You are asked to calibrate an O2 analyzer. What gases would you use for this procedure? 1. 100% oxygen. 2. 50% oxygen. 3. 21% oxygen (room air).
1 and 3
A practitioner forgets to ice an ABG sample and leaves it at room temperature for 45 min. What parameters can you predict will increase in this sample during that period? 1. PCO2 2. pH 3. PO2
1 only
Before attaching a transcutaneous blood gas monitor sensor to a patient, what should you do? 1. Provide a specified warm-up time and set the probe temperature. 2. Check the membrane and prepare a sensor with an adhesive ring and gel. 3. Prepare the monitoring site (remove excess hair and clean the skin).
1, 2 and 3
Most pre-analytical ABG errors can be avoided by ensuring that the sample is what? 1. properly anticoagulated 2. obtained anaerobically 3. analyzed within 15 to 30 minutes
1, 2 and 3
To avoid the dilution effects caused by too much sodium heparin during ABG sampling of an adult, what should you do? 1. Ensure a sample volume greater than 2 ml. 2. Use dry heparin instead. 3. Fill the needle dead space only.
1, 2 and 3
What are the clinical indications for arterial blood analysis? 1. Sudden, unexplained dyspnea 2. Cardiopulmonary resuscitation 3. Changes in ventilator settings 4. Chest pain
1, 2 and 3
What are the conditions for transcutaneous blood gas monitoring? 1. Transcutaneous blood gas monitoring provides a reasonable estimate of PaO2 and PaCO2. 2. Transcutaneous blood gas monitoring is most accurate when used with older adults. 3. Accurate estimates of transcutaneous blood gases are difficult in patients with shock. 4. Transcutaneous blood gas monitors use heated skin electrodes to arterialize the blood.
1, 2 and 3
What are the considerations about a blood gas analyzer's waste fluids? 1. A strong disinfectant should be added to waste fluid containers. 2. Waste fluids should be handled as if they were blood samples. 3. Waste fluids should be treated as potentially infectious.
1, 2 and 3
What does the required equipment and supplies for percutaneous arterial blood sampling of an adult include? 1. antiseptic (alcohol or Betadine) 2. patient or sample label 3. 20- to 22-gauge needle 4. local anesthetic
1, 2 and 3
What sites are used for arterial blood sampling by percutaneous needle puncture? 1. femoral 2. radial 3. brachial 4. carotid
1, 2 and 3
Why is the radial artery the preferred site for arterial blood sampling? 1. It is near the surface and easy to palpate and stabilize. 2. The ulnar artery normally provides good collateral circulation. 3. The radial artery is not near any large veins.
1, 2 and 3
transcutaneous blood gas monitoring is indicated when what need exists? 1. to continuously analyze gas exchange in infants or children 2. to quantify the real-time responses to bedside interventions 3. to continuously monitor for hyperoxia in newborn infants
1, 2 and 3
After obtaining an arterial blood sample, what should you do? 1. Apply pressure to the puncture site until bleeding stops. 2. Place the sample in a transport container with ice slush. 3. Check to see if the patient is getting anticoagulant therapy. 4. Mix the sample by rolling and inverting the syringe.
1, 2 and 4
What are the indications for capnography? 1. evaluating the response to therapies affecting ventilation/perfusion ratio ( ) relationships 2. determining the position of an artificial airway (trachea versus esophagus) 3. assessing a patient's readiness for weaning from ventilatory support 4. monitoring the integrity of the ventilatory circuit and artificial airway
1, 2 and 4
What are the reasons for finding an alternative site for arterial puncture? 1. failed Allen test 2. history of peripheral vascular disease 3. anticoagulation therapy 4. presence of a surgical shunt
1, 2 and 4
What can help avoid the problem of arterial blood sample contamination with air? 1. discarding frothy samples 2. fully expelling any bubbles 3. mixing before expelling air 4. capping syringe quickly
1, 2 and 4
What are the precautions and/or possible complications of arterial puncture? 1. arteriospasm 2. embolization 3. infection 4. hemorrhage
1, 2, 3 and 4
What chart information should be checked before performing artery puncture? 1. patient's primary diagnosis and history 2. presence of bleeding disorders or blood-borne infections 3. anticoagulant or thrombolytic drug prescriptions 4. respiratory care orders (e.g., O2 therapy)
1, 2, 3 and 4
What do the components of a laboratory blood gas analyzer include? 1. three-electrode measuring chamber 2. reagent containers 3. calibrating gas tanks 4. waste container
1, 2, 3 and 4
What guidelines should you adhere to when performing pulse oximetry? 1. Never mix different sensors among different devices. 2. Make sure that the sensors are the correct size and are properly applied. 3. Avoid using pulse oximetry to monitor hyperoxia in neonates. 4. Whenever possible, validate the initial SpO2 against the actual SaO2.
1, 2, 3 and 4
A physician requests that you obtain and set up an arterial line system for invasive monitoring of blood pressure. What equipment would you gather? 1. pressurized intravenous bag 2. continuous flush device 3. arterial catheter 4. pressure transducer 5. amplifier or monitor
1, 2, 3, 4, and 5
A blood gas analyzer measures what? 1. HCO3 2. PCO2 3. PO2 4. pH
2, 3 and 4 (recheck)
What are the consideration about capillary blood gas sampling? 1. Capillary sampling can be used in lieu of direct arterial access in some infants and small children. 2. A capillary sample PO2 provides a fairly close estimate of actual arterial oxygenation. 3. Clinicians should exercise caution when using capillary samples to guide decisions. 4. Properly obtained capillary blood can provide estimates of arterial pH and PCO2 levels.
1, 3 and 4
What are the considerations about invasive versus noninvasive monitoring? 1. Invasive procedures require insertion of a device into the body. 2. Laboratory analysis of gas exchange is usually noninvasive in nature. 3. Physiologic monitoring can be either invasive or noninvasive. 4. Invasive procedures provide more accurate data but carry greater risks.
1, 3 and 4
What are the considerations about the galvanic fuel cell O2 analyzer? 1. It actually measures the PO2 and not the O2 concentration. 2. It requires an external power source (alternating current line or batteries). 3. It has a slower response time than the Clark electrode. 4. Its fuel cells deplete and must be periodically replaced.
1, 3 and 4
What are the indications for pulse oximetry? 1. to assess changes in HbO2 during certain procedures 2. for measurements of abnormal Hb 3. to comply with external regulations or recommendations 4. to monitor the adequacy of HbO2 saturation
1, 3 and 4
What factors contribute to imprecision (random) errors during blood gas analysis? 1. sample contamination 2. contaminated buffers 3. statistical probability 4. sample mishandling
1, 3 and 4
Capillary puncture should be performed at or through what location? 1. Edematous tissue 2. Areas with new signs of infection 3. The heal of neonates 4. Previous puncture sites
2 and 3
Warming a capillary bed to 42 C has what effect? 1. It constricts the underlying blood vessels. 2. It increases blood flow well above tissue needs. 3. It "arterializes" the capillary blood.
2 and 3
What should be monitored during the sampling of arterial blood? 1. blood pressure proximal to puncture site 2. presence of pulsatile blood return 3. presence of air bubbles or clots in sample 4. appearance of puncture site
2, 3 and 4
What will result in falsely low HbO2 readings with a pulse oximeter? 1. sickle cell anemia 2. high levels of fetal Hb 3. elevated bilirubin levels 4. dirty cuvet chamber
2, 3 and 4
A PaO2 below what value would be considered moderate hypoxemia? a. 60 mm Hg b. 50 mm Hg c. 40 mm Hg d. depends on the FIO2
b. 50 mm Hg
At the very beginning of exhalation, the PETCO2 normally should be at what level? a. 0 mm Hg b. 15 mm Hg c. 25 mm Hg d. 40 mm Hg
a. 0 mm Hg
What is the normal gradient between PaCO2 and PETCO2? a. 3 to 5 mm Hg b. 5 to 10 mm Hg c. 10 to 15 mm Hg d. 15 to 20 mm Hg
a. 3 to 5 mm Hg
You obtain an SpO2 reading of 90% using an oximeter with an approximate accuracy of 5%. This could indicate a PO2 as low as what level? a. 55 mm Hg b. 60 mm Hg c. 65 mm Hg d. 70 mm Hg
a. 55 mm Hg
To measure PCO2, blood gas analyzers use what electrode? a. Severinghaus b. Clark c. Sahn d. White
a. Severinghaus
When performing a percutaneous needle puncture of the radial artery, you get only a small spurt of blood. What is the best action at this time? a. Slowly withdraw the needle until a pulsatile flow fills the syringe. b. Pull out entirely, use a different angle and then reinsert it. c. Slowly advance the needle until a pulsatile flow fills the syringe. d. Repeat the procedure with a fresh blood gas kit.
a. Slowly withdraw the needle until a pulsatile flow fills the syringe.
An alert outpatient awaiting bronchoscopy has an SpO2 reading of 81% breathing room air. The patient appears in no distress and exhibits no signs of hypoxemia. What would be the best initial action to take in this situation? a. Switch sites or replace the sensor probe. b. Immediately start O2 therapy. c. Obtain an ABG. d. Cancel the bronchoscopy procedure.
a. Switch sites or replace the sensor probe.
The total instrument error (inaccuracy) of a blood gas analyzer equals what? a. bias + imprecision b. imprecision + random error c. bias + systematic error d. trend error + bias
a. bias + imprecision
What patient parameters does not need to be assessed as part of arterial blood sampling? a. blood pressure b. temperature c. position or activity level d. clinical appearance
a. blood pressure
What is the greatest hazard of pulse oximetry? a. false results leading to incorrect decisions b. pressure sores at the measuring site c. skin burns due to using incompatible probes d. electrical shock at the measuring site
a. false results leading to incorrect decisions
What is the most common technique used to measure CO2 in respiratory gases? a. infrared absorption b. mass spectroscopy c. photoacoustics d. Raman scattering
a. infrared absorption
What is the best site for capillary puncture in an infant? a. lateral aspect of the heel's plantar surface b. anterior curvature of the heel c. medial aspect of the heel's plantar surface d. posterior curvature of the heel
a. lateral aspect of the heel's plantar surface
You are asked to provide continuous monitoring of the FiO2 provided by a humidified O2 delivery system using a galvanic cell analyzer. Where would you install the analyzer's sensor? a. proximal to the heated humidifier b. on the expiratory side of the circuit c. distal to the heated humidifier d. as close to the patient as possible
a. proximal to the heated humidifier
You must immediately begin monitoring the oxygenation status of an infant admitted to the emergency department in severe respiratory distress. What approach would you select? a. pulse oximetry (SpO2) b. transcutaneous monitoring (PtcO2) c. arterial puncture (PaO2) d. intraarterial optode monitoring
a. pulse oximetry (SpO2)
What is the advantage that point-of-care testing has over traditional laboratory testing? a. reduces turnaround time b. utilizes equipment that is less expensive c. does not require trained personnel to run the tests d. is more accurate than traditional laboratory testing
a. reduces turnaround time
After obtaining an arterial blood sample through percutaneous puncture using a syringe that does not have a capping safety device, what should you do? a. Remove the needle with a Kelly clamp, then plug the syringe. b. "Scoop" the needle cap up with one hand, then plug the syringe. c. Force the needle into a rubber cork or plastic stopper. d. Manually remove and bend the needle, then plug the syringe.
b. "Scoop" the needle cap up with one hand, then plug the syringe.
Pulse oximeter readings are generally unreliable at saturations below what level? a. 70% b. 80% c. 90% d. 95%
b. 80%
What is a normal end-tidal PETCO2 range? a. 30 to 38 mm Hg b. 35 to 43 mm Hg c. 38 to 46 mm Hg d. 42 to 50 mm Hg
b. 35 to 43 mm Hg
What is the normal range for end-tidal CO2 as measured by capnography? a. 0% to 5% b. 5% to 6% c. 6% to 8% d. 35% to 45%
b. 5% to 6%
Statistically derived limits for internal quality control of blood gas samples are usually set at what appropriate level? a. 1 standard deviation from the mean b. 2 standard deviations from the mean c. 3 standard deviations from the mean d. 5 standard deviations from the mean
b. 2 standard deviations from the mean
What is the appropriate interval for changing the site for a transcutaneous blood gas monitor sensor? a. 1 to 2 hours b. 2 to 6 hours c. 6 to 8 hours d. 8 to 12 hours
b. 2 to 6 hours
Under ideal conditions, electrochemical oxygen (O2) analyzers have approximately what degree of accuracy? a. 1% b. 2% c. 3% d. 4%
b. 2%
After obtaining an arterial blood sample from an arterial line, what would you do? a. Flush the line and stopcock with the heparinized intravenous solution. b. Aspirate at least 5 ml of fluid or blood (dead space or waste). c. Confirm stopcock port open to intravenous bag solution and catheter. d. Confirm undamped pulse pressure waveform on monitor.
b. Aspirate at least 5 ml of fluid or blood (dead space or waste).
Before connecting the sample syringe to an adult's arterial line stopcock, what would you do? a. Flush the line and stopcock with the heparinized intravenous solution. b. Aspirate at least 5 ml of fluid or blood using a waste syringe. c. Align the stopcock off to the patient and on to the flush solution. d. Increase the flush-solution bag pressure by 20 to 30 mm Hg.
b. Aspirate at least 5 ml of fluid or blood using a waste syringe.
Describe the correct procedure for an Allen's test. a. Compress both the radial and ulnar arteries, then release the radial artery. b. Compress both the radial and ulnar arteries, then release the ulnar artery. c. Compress both the radial and ulnar arteries, then release both arteries at once. d. Compress the brachial artery only and observe circulation to the hand.
b. Compress both the radial and ulnar arteries, then release the ulnar artery.
Before performing puncture or cannulation of the radial artery, what should you do? a. Fix and tighten a tourniquet above the antecubital fossa. b. Perform the Allen test to ensure collateral circulation. c. Inject heparin into the adjoining subcutaneous tissues. d. Apply firm pressure to the arterial site for 5 minutes.
b. Perform the Allen test to ensure collateral circulation.
What is the measurement of CO2 in respiratory gases called? a. oximetry b. capnometry c. optometry d. barometryb. capnometry
b. capnometry
How is the accuracy of a blood gas analyzer determined? a. examining the repeatability of the analyzer's results b. comparing the analyzer's measurements to known values c. adjusting the offset (or balance) of the instrument d. adjusting the gain (or slope) of the instrument
b. comparing the analyzer's measurements to known values
What would you expect to occur if too much heparin was used in gathering an ABG sample from a patient breathing room air? a. increase in HCO3- b. decrease in PCO2 c. decrease in pH d. decrease in PO2
b. decrease in PCO2
When analyzing an ABG sample from a patient with acute respiratory distress syndrome and refractory hypoxemia, you notice a PaO2 of 141 mm Hg and a PaCO2 of 14 mm Hg. What analytic errors should you suspect? a. excessive time since sample collection b. exposure of the blood sample to air c. excessive heparin in the sample d. sample admixture with venous blood
b. exposure of the blood sample to air
What is not a common tissue injury to be on guard for at the site of transcutaneous blood gas electrode placement? a. erythema b. hematomas c. burns or blisters d. skin tears
b. hematomas
If patient pain or anxiety occurs during arterial puncture, what will probably occur? a. hypoventilation b. hyperventilation c. respiratory acidosis d. hypoxemia
b. hyperventilation
During a single-breath capnogram, the sharp downstroke and return to baseline that normally occurs after the end-tidal point indicates what? a. exhalation of mainly dead space gas b. inspiration of fresh respiratory gas c. exhalation of mixed alveolar and dead space gas d. exhalation of mainly alveolar gas
b. inspiration of fresh respiratory gas
A patient suffering from traumatic brain injury in the ICU has a PtO2 (tissue oxygen) value of 10 to 15 mm Hg, what does this indicate? a. normal intracranial pressure b. ischemic brain damage c. normal cerebral perfusion d. cerebral hyperperfusion
b. ischemic brain damage
A patient being monitored by capnography exhibits a sudden rise in end-tidal CO2 levels. What are possible causes? a. sudden release of a tourniquet b. massive pulmonary embolism c. sudden increase in cardiac output d. injection of NaHCO3
b. massive pulmonary embolism
Which blood gas analyzer electrode uses a separate reference electrode? a. O2 b. pH c. Clark d. HCO3
b. pH
What is the most common source of error and false alarms with pulse oximetry? a. presence of HbCO b. patient motion artifact c. presence of vascular dyes d. ambient light detection
b. patient motion artifact
What is the process of testing a new blood gas analyzer to confirm a manufacturer's claims? a. automated calibration b. performance validation c. proficiency testing d. preventive maintenance
b. performance validation
What is a normal level for CaO2? a. 12 to 15 ml/100 ml b. 14 to 16 ml/100 ml c. 18 to 20 ml/100 ml d. 16 to 22 ml/100 ml
c. 18 to 20 ml/100 ml
After changing the FiO2 of a critically ill patient, how long should you wait to draw an ABG to monitor the patient's respiratory status? a. 5-10 minutes b. 10-20 minutes c. 20-30 minutes d. 30-40 minutes
c. 20-30 minutes
Under ideal conditions, pulse oximeter readings patients usually fall in what range of those obtained with invasive hemoximetry? a. 1% to 2% b. 2% to 3% c. 3% to 5% d. 5% to 7%
c. 3% to 5%
For continuous monitoring of adults and children, you should set a pulse oximeter's low alarm in what range? a. 80% to 85% b. 85% to 88% c. 88% to 92% d. 93% to 97%
c. 88% to 92%
When is capillary blood gas sampling indicated? a. There is a need for direct analysis of blood oxygenation. b. Normal noninvasive monitor readings need to be checked. c. ABG analysis is needed, but arterial access is not available. d. Continuous data on patient ventilation status are needed.
c. ABG analysis is needed, but arterial access is not available.
How often should blood gas calibration verification by control media take place? a. At least one level of control media should be analyzed every 8 hours. b. At least two levels of control media should be analyzed every day. c. At least two levels of control media should be analyzed every 8 hours. d. At least two levels of control media should be analyzed every hour.
c. At least two levels of control media should be analyzed every 8 hours.
While monitoring an active infant through a transcutaneous blood gas system, you notice a rapid rise in PtcO2 from 63 to 145 mm Hg. At that same time, the (PtcCO2) drops from 35 to 7 mm Hg. What is the most appropriate action in this case? a. Perform a quick assessment of the infant's airway. b. Stabilize the infant and call for emergency assistance. c. Check the sensor for air leaks or dislodgment. d. Remove the sensor and recalibrate the instrument.
c. Check the sensor for air leaks or dislodgment.
To validate patient readings obtained from a transcutaneous blood gas monitor, what should you do? a. Measure and compare the PtcO2 and PtcCO2 at three or more different sites. b. Compare the monitor's readings to a concurrent pulse oximetry reading. c. Compare the monitor's readings to those obtained with a concurrent ABG sample. d. Compare the patient reading to those obtained when calibrating the sensor.
c. Compare the monitor's readings to those obtained with a concurrent ABG sample.
Because of an extremely low PO2, you suspect that an arterial blood sample taken from a patient's brachial artery might have been contaminated with venous blood. What might help to confirm your suspicion? a. Call the lab to get the latest chemistry report. b. Inspect the sample for color and consistency. c. Cross-check the sample with a SpO2 reading. d. Measure the sample's actual hemoglobin saturation.
c. Cross-check the sample with a SpO2 reading.
How does the Clark polarographic O2 electrode function? a. It measures the magnetic properties of O2 versus N2. b. It measures the electrical potential across a Wheatstone bridge. c. It uses O2 to produce a reduction-oxidation reaction. d. It measures the comparative cooling effect on a heated wire.
c. It uses O2 to produce a reduction-oxidation reaction.
While checking a polarographic (Clark) electrode, you determine that the device fails to read 100% when exposed to pure O2. What action would be the proper first step? a. Check the silica crystals. b. Send the device out for repair. c. Replace the analyzer's batteries. d. Change the analyzer's fuel cell.
c. Replace the analyzer's batteries.
An outpatient scheduled for an arterial blood sample enters the pulmonary lab 20 min late and out of breath, having run up four flights of stairs. What should you do? a. Postpone the blood sample until tomorrow. b. Scold the patient for being so late. c. Wait 5 minutes before taking the sample. d. Scold the patient for using the stairs.
c. Wait 5 minutes before taking the sample.
What can cause false high readings when using a pulse oximeter? a. fetal hemoglobin b. intravascular dyes c. carboxyhemoglobin d. presence of metHb
c. carboxyhemoglobin
Through which pulmonary artery catheter port would you obtain a mixed venous blood sample? a. proximal (right atrium) port b. catheter thermistor connector c. distal (catheter tip) port d. balloon inflation port
c. distal (catheter tip) port
During capnography monitoring of a mechanically ventilated patient, you note that the PETCO2 has dropped to 0 mm Hg. What is the most likely problem? a. ventilator disconnection b. esophageal intubation c. increased cardiac output d. cardiac arrest
c. increased cardiac output
The shape of the expired CO2 tracing of a patient is normal but instead of being zero, the baseline is elevated to approximately 12 mm Hg. What is the most likely problem? a. patient disconnected from the system b. obstruction of the sampling tube c. rebreathing d. presence of N2O
c. rebreathing
You obtain an SpO2 reading of 100% on a patient receiving O2 through a nonrebreathing mask. What range of PaO2 levels is possible in this patient? a. 60 to 90 mm Hg b. 90 to 100 mm Hg c. 100 to 200 mm Hg d. 100 to 600 mm Hg
d. 100 to 600 mm Hg
How long should you wait before drawing an ABG on a chronic obstructive pulmonary disease (COPD) patient whose FiO2 has just been changed? a. 5 to 10 minutes b. 10 to 15 minutes c. 15 to 20 minutes d. 20 to 30 minutes
d. 20 to 30 minutes
During calibration of a Clark polarographic O2 analyzer, you cannot get the sensor to read 100% when exposed to 100% O2, even after adjusting its calibration control. The unit has new batteries. What action should you do next? a. Use it only with low Fio2 values. b. Send the device out for repair. c. Replace the unit's batteries. d. Change the sensor or electrode.
d. Change the sensor or electrode.
You determine that a blood gas sample that requires analysis has been sitting in ice slush for 90 min. What should you do? a. Go ahead and analyze the sample (because it was on ice). b. Warm the sample to room temperature before analysis. c. Readjust the blood gas analyzer temperature to 0 C. d. Discard the sample and notify the appropriate clinician.
d. Discard the sample and notify the appropriate clinician.
When performing an Allen test on the left hand of a patient, you notice that the palm, fingers, and thumb remain blanched for more than 15 sec after pressure on the ulnar artery is released. What should you do? a. Use the brachial site for sampling. b. Sample from the contralateral radial artery. c. Use the femoral site for sampling. d. Perform the Allen test on the right hand.
d. Perform the Allen test on the right hand.
During continuous monitoring of an active 5-year-old patient with a finger pulse oximetry probe, you obtain frequent and repeated false low HbO2 alarms (<90%). What would be the best action to take in this situation? a. Sedate the patient and restrain the arms. b. Reset the low alarm limit to the 80% to 85% range. c. Use a spot check instead of continuous monitoring. d. Relocate the sensor to a more stable location.
d. Relocate the sensor to a more stable location.
During a single-breath capnogram, what does the occurrence of a plateau indicate? a. exhalation of mainly dead space gas b. inspiration of fresh respiratory gas c. exhalation of mixed alveolar and dead space gas d. exhalation of mainly alveolar gas
d. exhalation of mainly alveolar gas
What are the possible complications of capillary blood gas sampling? a. infection b. hematoma c. hemorrhage d. hypotension
d. hypotension
To ensure that the output of a blood gas analyzer is both accurate and linear across the range of measured values, a calibration procedure must measure what? a. two different parameters at the same time b. parameters with known input values at one point c. two different parameters at different times d. parameters with known input values at two points
d. parameters with known input values at two points
In what type of patients would transcutaneous blood gas monitoring most likely provide inaccurate or erroneous results? a. newborn infant with respiratory distress syndrome (RDS) b. patient with hypoxemia c. patient with a hyperpyrexia d. patient in hypovolemic shock
d. patient in hypovolemic shock
To assess gas exchange at the tissues, you would obtain a blood sample from what? a. pulmonary artery (balloon-deflated) b. peripheral artery (radial, brachial) c. central vein (superior or inferior vena cava) d. pulmonary artery (balloon-inflated)
d. pulmonary artery (balloon-inflated)
Analysis of an arterial blood sample taken from a healthy athlete reveals a pH of 7.36, a PCO2 of 45 mm Hg, and a PO2 of 43 mm Hg. What analytic errors should you suspect? a. excessive time since sample collection b. exposure of the blood sample to air c. excessive heparin in the sample d. sample admixture with venous blood
d. sample admixture with venous blood
Oximetry is the measurement of blood hemoglobin saturations using what technique? a. electrochemical dissociation b. photoplethysmography c. photochemical reactions d. spectrophotometry
d. spectrophotometry
