Chapter 19

After obtaining an arterial blood sample through percutaneous puncture using a syringe that does not have a capping safety device, what should you do?

"Scoop" the needle cap up the one hand, then plug the syringe

How long should you wait before drawing an ABG on a chronic obstructive pulmonary disease (COPD) patient whose FIO2 has just been changed?

20 to 30 minutes

What size needle would you recommend to obtain an ABG sample through percutaneous puncture of an infant?

25 guage

Which of the following is False about the galvanic fuel cell O2 analyzer?

It requires an external power source [alternating current line or batteries]

How does the Clark Polarographic O2 electrode function?

It uses O2 to produce a reduction-oxidation reaction

Patient parameters that should be assessed as part of arterial blood sampling include all of the following except:

Blood pressure

Which of the following is false about invasive versus noninvasive monitoring?

Laboratory analysis of gas exchange is usually noninvasive in nature

While checking a polarographic [Clark] electrode, you determine that the device fails to read 100% when exposed to pure O2. Which of the following action would be the proper first stept?

Replace the analyzer's batteries

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. Which of the following actions would be correct?

Replace the unit's batteries

At the very beginning of exhalation, the PETCO2 normally should be at what level?

a. 0mmHg

The equipment necessary for capillary blood sampling includes all of the following except:

a. 1-ml syringe

You obtain a SpO2 reading of 100% on a patient receiving O2 through a nonrebreathing mask. What range of PaO2 levels is possible in this patient?

a. 100 to 600 mmHg

What is a normal level for CaO2?

a. 18 to 20 ml/100 ml

Statistically derived limits for internal quality control of blood gas samples are usually set at what appropriate level?

a. 2 standard deviations from the mean

What is the appropriate interval for changing the site for a transcutaneous blood gas monitor sensor?

a. 2 to 6 hours

After changing the FIO2 of a patient with emphysema, how long should you wait to draw an ABG to monitor the patient's respiratory status?

a. 20-30 minutes

What is the normal gradient between PaCO2 and PETCO2?

a. 3 to 5 mmHg

Under ideal conditions, pulse oximeter readings patients usually fall in what range of those obtained with invasive hemoximetry?

a. 3% to 5%

What is a normal end-tidal PETCO2 range?

a. 35 to 43mmHg

What is the normal range for end tidal CO2 as measured by capnography?

a. 5% to 6%

A PaO2 below what value would be considered moderate hypoxemia?

a. 50 mm Hg

You are asked to calibrate an O2 analyzer. Which of the following gases would you use for this procedure?

a. 50% oxygen b. 21% oxygen

You obtain a SpO2 reading of 90% using an oximeter with an approximate accuracy of 5%. This could indicate a PO2 as low as what level?

a. 55mmHg

Pulse oximeter readings are generally unreliable at saturations below what level?

a. 80%

For continuous monitoring of adults and children, you should set a pulse oximeter's low alarm in what range?

a. 88% to 92%

All of the following are TRUE about capillary blood gas sampling except:

a. A capillary sample PO2 provides a fairly close estimate of actual arterial oxygenation

Tissue injuries to be on guard for at the site of transcutaneous blood gas electrode placement include all of the following except which one?

a. Hematomas

If patient pain or anxiety occurs during arterial puncture, which of the following will probably occur?

a. Hyperventilation

Possible complications of capillary blood gas sampling include all of the following except:

a. Hypotension

When conducting ABG analysis in the laboratory, obvious signs of pre-analytical error include all of the following except?

a. Iced sample

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?

a. Inadequate warming of the capillary bed b. Squeezing of the puncture site

A mechanically ventilatied patient exhibits a sudden decrease in end-tidal CO2 levels. All of the following are possible causes of this change except:

a. Increase in CO2 production

During capnography monitoring of a mechanically ventilated patient, you note that the PETCO2 had dropped to 0mmHg. All of the following are possible causes of this finding except:

a. Increased cardiac output

Capillary puncture should NOT be performed at or through what location? (all of the above)

a. Inflamed or edematous tissue b. Localized areas of infection c. The fingers of neonates d. Previous puncture sites

What is the most common technique used to measure CO2 in respiratory gases?

a. Infrared absorption

During a single-breath capnogram, the sharp downstroke and return to baseline that normally occurs after the end-tidal point indicates what?

a. Inspiration of fresh respiratory gas

A patient suffering from traumatic brain injury in the ICU has a PtO2 (tissue oxygen) value of 10-15mmHg, what does this indicate?

a. Ischemic brain damage

Warming a capillary bed to 42 degree C has which of the following effects?

a. It increases blood flow well above tissue needs b. It "arterializes" the capillary blood

What is the best site for capillary puncture in an infant?

a. Lateral aspect of the heel's plantar surface

A patient being monitored by capnography exhibits a sudden rise in end-tidal CO2 levels. All of the following are possible causes of this change except:

a. Massive pulmonary embolism

All of the following can help avoid the problem of arterial blood sample contamination with air except:

a. Mixing before expelling air

Which of the following indicates venous admixture during arterial puncture?

a. Need to use syringe suction b. Small sample volumes

Which of the following guidelines should you adhere to when performing pulse oximetry?

a. Never mix different sensors among different devices b. Make sure that the sensors are the correct size and are properly applied c. Avoid using pulse oximetry to monitor hyperoxia in neonates d. Whenever possible, validate the initial SpO2 against the actual SaO2

To avoid transmission of blood-born disease when handling a used needle, what should you do?

a. Never recap the needle without a safety device (or scoop method) b. Never handle the needle with both hands, or point it toward the body c. Never bend, break, or remove the needle from the syringe by hand d. Always dispose of the syringe or needle in a proper sharps container

All of the following are advantages of mainstream capnometry except:

a. No bulky sensor

Continuous SpO2 monitoring (versus a spot check) is indicated in all of the following situations except:

a. O2 therapy

A practitioner forgets to ice an ABG sample and leaves it at room temperature for 45 minutes. Which of the following parameters can you predict will increase in this sample during that period?

a. PCO2

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. Parameters with known input values at two points

In which of the following patients would transcutaneous blood gas monitoring most likely provide inaccurate or erroneous results?

a. Patient in hypovolemic shock

What is the most common source of error and false alarms with pulse oximetry?

a. Patient motion artifact

What chart information should be checked before performing artery puncture? (all the above)

a. Patient's primary diagnosis and history b. Presence of bleeding disorders or blood-borne infections c. Anticoagulant or thrombolytic drug prescriptions d. Respiratory care orders

All of the following must be charted after obtaining an ABG sample through the brachial artery except

a. Patient's temperature, position, activity level

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 seconds after pressure on the ulnar artery is released. What should you do?

a. Perform the Allen test on the right hand

What is the process of testing a new blood gas analyzer to confirm a manufacturer's claims?

a. Performance validation

What media are used to calibrate a blood gas analyzer's gas electrodes?

a. Precision mixtures of O2 and CO2

A physician requests that you obtain and set up an arterial line system for invasive monitoring of blood pressure. Which of the following equipment would you gather? (all of the above)

a. Pressurized intravenous bag b. Continuous flush device c. Arterial catheter d. Pressure transducer e. Amplifier or monitor

What is the quality control procedure of analysis and reporting on externally provided control media with unknown values?

a. Proficiency testing

Most preanalytical ABG errors can be avoided by ensuring that the sample is which of the following? (all of the above)

a. Properly anticoagulated b. Obtained anaerobically c. Analyzed within 15 to 30 minutes

Before attaching a transcutaneous blood gas monitor sensor to a patient, what should you do? (all of the above)

a. Provide a specified warm up time and set the probe temperature b. Check the membrane and prepare sensor with an adhesive ring and gel c. Prepare the monitoring site (remove excess hair and clean the skin)

You are asked to perform an ABG on a patient that comes into the ER feeling light-headed with a blood pressure of 90/60. What may you need to do to obtain an adequate blood sample on this patient?

a. Pull gently on the syringe barrel to apply suction

To assess gas exchange at the tissues, you would obtain a blood sample from which of the following?

a. Pulmonary artery (ballon-inflated)

You must immediately begin monitoring the oxygenation status of an infant admitted to the emergency department in severe respiratory distress. Which of the following approaches would you select?

a. Pulse oximetry (SPO2)

You return to a patient's room 20 minutes after drawing an ABG. Which of the following should you check at this time?

a. Puncture site for hematoma b. Adequacy of distal circulation

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?

a. Random error b. Systematic error

Potential benefits of continuous, intraarterial (in Vivo) blood gas analysis include:

a. Real time monitoring b. Less blood loss c. Lower infection risk d. Elimination of specimen transport

The shape of the expired CO2 tracing of a patient is normal but instead of being zero, the baseline is elevated to about 12mmHg. Which of the following is the most likely problem?

a. Rebreathing

The advantage that point of care testing has over traditional laboratory testing is that the point of care testing:

a. Reduces turnaround time

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 (less than 90%). Which of the following would be the best action to take in this situation?

a. Relocated the sensor to more stable location

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)?

a. Repeat the analysis on a different analyzer b. Rerun the control sample a second time

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. Which of the following analytic errors should you suspect?

a. Sample admixture with venous blood

To measure PCO2, blood gas analyzers use what electrode?

a. Severinghaus

All of the following can result in falsely high HbO2 readings with a laboratory hemoximeter except:

a. Sickle cell anemia

All of the following factors determine the volume needed for an arterial blood sample except:

a. Site used for sampling

When performing a percutaneous needle puncture of the radial artery, you get only a small spurt of blood. Which of the following is the best action at this time?

a. Slowly withdraw the needle until a pulsatile flow fills the syringe

Oximetry is the measurement of blood hemoglobin saturations using what technique?

a. Spectrophotometry

Factors contributing to bias (systematic) errors during blood gas analysis include all of the following except:

a. Statistical probability

An alert outpatient awaiting bronchoscopy has a SpO2 reading of 81% breathing room air. The patient appears in no distress and exhibits no signs of hypoxemia. Which of the following would be the best initial action to take in this situation?

a. Switch sites or replace the sensor probe

A mixed venous blood sample obtained from a pulmonary artery catheter sample has a PO2 of 85 mmHg and a hemoglobin saturation of 95%. Which of the following is likely?

a. The pulmonary artery catheter balloon was not deflated b. The blood sample was withdrawn too quickly

All of the following are common sites for transcutaneous blood gas electrode placement except the:

a. Thigh

Components of a laboratory blood gas analyzer include which of the following? (all of the above)

a. Three-electrode measuring chamber b. Reagent containers c. Calibrating gas tanks d. Waste container

Which of the following is NOT a use of capnometry?

a. To assess the condition of the alveolar-capillary membrane

All of the following site are used for arterial blood sampling by percutaneous needle puncture except:

carotid

All of the following are grounds for finding an alternative site for arterial puncture except:

presence of surgical shunt

Treatment parameters that should be assessed as part of arterial blood sampling include all of the following except

time of last incentive breathing exercise

Why is the radial artery the preferred site for arterial blood sampling?

-It is near the surface and easy to palpate and stabilize -the ulnar artery normally provides good collateral circulation -The radial artery is not near any large veins

Precautions and/or possible complications of arterial puncure include which of the following?

-arteriospasm -embolization -infection -hemorrhage

Which of the following should be monitored during the sampling of arterial blood?

-presence of pulsatile blood return -presence of air bubbles or clots in sample -appearance of puncture site

Purposes of a needle capping device include which of the following

-to isolate the sample from air exposure -to help prevent needle stick injuries

Under ideal conditions, electrochemical oxygen analyzers have approximately what degree of accuracy?

2%

Indications for arterial blood sampling by percutaneous needle puncture include all of the following except the need to:

Assess the adequacy of tissue oxygenation

Required equipment and supplies for percutaneous arterial blood sampling of an adult include all of the following except:

Local anesthetic

Before performing puncture or cannulation of the radial artery, what should you do?

Perform the Allen test to ensure collateral circulation

You are asked to provide continuous monitoring the FIO2 provided by a humidified O2 delivery system using a galvanic cell analyzer. Where would you install the analyzer's sensor?

Proximal to the heated humidifier

Which of the following are TRUE about a blood gas analyzer's waste fluids?

a. A strong disinfectant should be added to waste fluid containers b. Waste fluids should be handled as if they were blood samples c. Waste fluids should be treated as potentially infectious

When is capillary blood gas sampling indicated?

a. ABG analysis is needed, but arterial access is not available

Before taking a spot reading with a pulse oximeter, what should you do?

a. Allow sufficient response time b. Set the low alarm to 88% to 90% c. Confirm adequacy of pulse signal

After obtaining an arterial blood sample, what should you do?

a. Apply pressure to the puncture site until bleeding stops b. Place the sample in a transport container with ice slush

After obtaining an arterial blood sample from an arterial line, you would do all of the following except

a. 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. Aspirate at least 5 ml of fluid or blood using a waste syringe

All of the following are indications for capnography except:

a. Assessing a patient's readiness for weaning from ventilator support

How often should blood gas calibration verification by control media take place?

a. At least two levels of control media should be analyzed every 8 hours

The total instrument error (inaccuracy) of a blood gas analyzer equals which of the following?

a. Bias + imprecision

What is the measurement of CO2 in respiratory gases called?

a. Capnometry

Which of the following can cause false high readings when using a pulse oximeter?

a. Carboxyhemoglobin

To avoid thermal injury with transcutaneous blood gas monitor sensors, what should you do?

a. Carefully monitor the sensor temperature b. Regularly rotate the sensor site

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?

a. Check the function of the PCO2 electrode b. Repair or replace any failed components

While monitoring an active infant through a transcutaneous blood gas system, you notice a rapid rise in PO2 from 63 to 145 mmHg. During the same time, the (PCO2) drops from 35 to 7 mmHg. What is the most appropriate action in this case?

a. Check the sensor for air leaks or dislodgment

To validate patient reading obtained from a transcutaneous blood gas monitor, what should you do?

a. Compare the monitor's reading to those obtained with a concurrent ABG sample

How is the accuracy of a blood gas analyzer determined?

a. Comparing the analyzer's measurements to known values

Which of the following describes the correct procedure for an Allen test?

a. Compress both the radial and ulnar arteries, then release the ulnar artery

Factors contributing to imprecision (random) errors during blood gas analysis include all of the following except

a. Contaminated buffers

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. Which of the following might help to confirm your suspicion?

a. Cross-check the sample with a SpO2 reading

All of the following will tend to cause false low readings when using a pulse oximeter except:

a. Dark nail polish

All of the following conditions make interpreting the results of a modified Allen test difficult except:

a. Dark skin pigmentation

Which of the following would you expect to occur if too much heparin was used in gathering an ABG sample from a patient breathing room air?

a. Decrease in PCO2

Which of the following changes would occur if an arterial blood sample of a patient breathing room air were exposed to a large air bubble?

a. Decreased PCO2 b. Increased PO2

You determine that a blood gas sample that requires analysis has been sitting in ice slush for 90 minutes. What should you do?

a. Discard the sample and notify the appropriate clinician

Through which pulmonary artery catheter port would you obtain a mixed venous blood sample?

a. Distal (catheter tip) port

To avoid the dilution effects caused by too much sodium heparin during ABG sampling of an adult, what should you do? (all the above)

a. Ensure a sample volume greater than 2 ml b. Use dry heparin instead c. Fill the needle dead space only

During a single-breath copnogram, what does the occurrence of a plateau indicate?

a. Exhalation of mainly alveolar gas

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. Which of the following analytic errors should you suspect?

a. Exposure of the blood sample to air

What is the greatest hazard of pulse oximetry?

a. False results leading to incorrect decisions

Indications for pulse oximetry include all of the following except the need

a. For measurements of abnormal Hb

Which of the following Centers for Disease Control and Prevention (CDC) barrier precautions would you use when obtaining an arterial blood gas (ABG) through percutaneous puncture?

a. Gloves b. Protective eyewear

A blood gas analyzer measures all of the following except:

a. HCO3

Transcutaneous blood gas monitoring is indicated when what need exists? (all of the above)

a. To continuously analyze gas exchange in infants or children b. To quantify the real time responses to bedside interventions c. To continuously monitor for hyperoxia in newborn infants

Which of the following is FALSE about transcutaneous blood gas monitoring?

a. Trancutaneous blood gas monitoring is most accurate when used with older adults

An outpatient scheduled for an arterial blood sample enters the pulmonary lab 20 minutes late and out of breath, having run up four flights of stairs. What should you do?

a. Wait 5 minutes before taking the sample

Before a sample of capillary blood is taken, what should you do to the site?

a. Warmed to 42 degree C for 10 minutes b. Squeezed lightly until blanched

Which blood gas analyzer electrode uses a separate reference electrode?

a. pH