During the middle of a 6-minute walk test, a patient complains of chest pain, exhibits diaphoresis and appears very pale. Which of the following actions should you immediately take?
- Administer O2 as needed: No; Re-take the vital signs: Yes; Sit the patient down: Yes
- Administer O2 as needed: No; Re-take the vital signs: Yes; Sit the patient down: No
- Administer O2 as needed: Yes; Re-take the vital signs: No; Sit the patient down: No
- Administer O2 as needed: Yes; Re-take the vital signs: Yes; Sit the patient down: Yes
You should immediately stop a 6MWT if the patient complains develops chest pain, intolerable dyspnea, leg cramps, staggering, diaphoresis, or a pale or ashen appearance. In these cases, sit the patient in the chair, re-take the vital signs, administer O2 as appropriate and arrange for a physician assessment. Once you are sure the patient is stable, record the time stopped, distance walked and the reason the patient could not continue.
Five minutes after elevating the pressure to 20 cm H2O during a CPAP titration study, a patient still exhibits obstructive respiratory events and some periods of central sleep apnea. What should be the next step in conducting this study?
- Stop the study and recommend alternative therapy for the sleep disorder
- Increase the CPAP pressure to 22 cm H2O for 5 minutes and continuing observing
- Begin titrating with BiPAP up to a maximum IPAP-EPAP = 10 cm H2O
- Maintain 20 cm H2O CPAP for an additional 10 minutes and continuing observing
During a CPAP titration study, you generally increase the CPAP level until the obstructive events are abolished or controlled, or until you reach a maximum CPAP level of 20 cm H2O. If there are continued obstructive respiratory events at high levels of CPAP (> 15 cm H2O) or the patient exhibits periods of central sleep apnea, you should consider a trial of BiPAP, starting at EPAP = 4 and IPAP = 8, with a recommended maximum IPAP-EPAP differential of 10 cm H2O and a maximum IPAP of 30 H2O.
To measure the amount of auto-PEEP present in a patient receiving ventilatory support, you would:
- measure pressure during an end-inspiratory pause
- measure pressure at volume increments using a super syringe
- measure pressure during an end-expiratory pause
- measure expiratory flow before and after bronchodilator
One can quantify the amount of auto-PEEP present by measuring the airway pressure during an end-expiratory pause. Accurate measurement requires that the patient be relaxed.
A 150 pound patient is breathing at a frequency of 20/minute, with a tidal volume of 550 mL. What is his estimated alveolar ventilation per minute?
- 11.00 L/min
- 8.00 L/min
- 3.00 L/min
- 14.00 L/min
The formula for alveolar minute ventilation is VE = f x (VT - VDS). In this case the physiologic deadspace is estimated at 1 mL/lb ideal body weight, or 150 mL. Substituting the patient's values for f, VT and estimated VDS, we compute an alveolar minute ventilation of 20 x (550-150) = 8,000 mL/ min, or 8.00 L/min.
Under which of the following conditions would you recommend ending a cardiopulmonary exercise evaluation?
- An ECG indicating supraventricular tachycardia: No; A 10% or greater fall from baseline in SpO2: Yes; A fall in systolic BP of more than 20 mm Hg: Yes; A request from the patient to stop the test: Yes
- An ECG indicating supraventricular tachycardia: No; A 10% or greater fall from baseline in SpO2: Yes; A fall in systolic BP of more than 20 mm Hg: No; A request from the patient to stop the test: Yes
- An ECG indicating supraventricular tachycardia: Yes; A 10% or greater fall from baseline in SpO2: No; A fall in systolic BP of more than 20 mm Hg: Yes; A request from the patient to stop the test: No
- An ECG indicating supraventricular tachycardia: Yes; A 10% or greater fall from baseline in SpO2: Yes; A fall in systolic BP of more than 20 mm Hg: Yes; A request from the patient to stop the test: Yes
Indications for ending a cardiopulmonary exercise evaluation include: (1) ECG abnormalities (e.g., dangerous dysrhythmias, ventricular tachycardia, ST-T wave changes); (2) severe desaturation (SaO2 < 80% or SpO2 < 83% and/or a 10% fall from baseline values; (3) angina; (4) hypotensive responses; (5) a fall of > 20 torr in systolic pressure, occurring after the normal exercise rise; (6) a fall in systolic blood pressure below the pre-exercise level; (7) lightheadedness; and (8) a request from the patient to stop the test.
Which of the following bedside measurements require a conscious and cooperative patient?
- spontaneous respiratory rate
- maximum expiratory pressure
- spontaneous tidal volume
- maximum inspiratory pressure
Vital capacity and maximum expiratory pressure measurements require that the patient be conscious and cooperative. Assuming there is spontaneous breathing present you could measure an unconscious patient's spontaneous respiratory rate and tidal volume (and minute volume), as well as the maximum inspiratory pressure (using a one-way valve system).
Data below were obtained from a patient's medical record:
PaO2:64 torrPaCO2:40 torrPvO2:33 torrPeCO2:30 torrSaO2:93%SvO2:64%
What is the patient’s deadspace to tidal volume (VD/VT) ratio?
To compute a patient’s deadspace, use the Bohr equation: VD/VT = (PaCO2 - PECO2) /PaCO2 where PECO2 is the mixed expired PCO2
In this case: VD/VT = (40 – 30) /40 = 10 /30 = 0.25
The proper starting point for FRC measurement via helium dilution or nitrogen washout is:
- end of a maximum exhalation
- end of a normal resting inspiration
- end of a maximum inhalation
- end of a normal resting exhalation
The validity of FRC measurement via either helium dilution or nitrogen depends on proper starting point, i.e., the end of a normal resting expiration. In addition, it is critical that the spirometer and breathing circuit be leak free and that the gas analyzers be properly calibrated.
You have just placed a COPD patient on SIMV at a rate of 8/min, a tidal volume of 700 mL, and an FIO2 of 0.45. In order to ensure proper equilibration between the alveolar and arterial gas tensions, how long should you wait before drawing an ABG?
- 30 min
- 20 min
- 15 min
- 10 min
The time needed for equilibration between the alveolar and arterial gas tensions depends the underlying disease process. In patients with lower than normal alveolar ventilation and larger than normal FRCs, such as those with COPD, equilibration times may be significantly longer than normal. In such patients, it is advisable to wait for 30 minutes after initiation of ventilatory support (or changing support parameters) before sampling the arterial blood.
The ER physician asks you to evaluate a trauma patient who was the victim of a house fire. In order to properly evaluate the cardiopulmonary status of this patient you should perform which of the following procedures?
- Glasgow coma scale
- pulse oximetry
- chest X-ray
Due to the patient’s involvement in a house fire you should immediately suspect the presence of carbon monoxide poisoning. Carbon monoxide’s high affinity for hemoglobin will cause profound hypoxemia. Standard two-wavelength pulse oximetry is unable to measure carbon monoxide saturations and is contraindicated to assess patients with suspected smoke inhalation. In order to assess for the presence of carbon monoxide in the blood you must run a CO-oximetry blood gas test.
The primary indication for apnea monitoring is to:
- prevent sudden infant death syndrome (SIDS)
- identify life-threatening events in neonates
- warn of ventilator disconnection or malfunction
- assess neonates for obstructive sleep apnea
The primary indication for apnea monitoring is to identify life-threatening events in neonates at risk of recurrent apnea, bradycardia and hypoxemia. Prevention of sudden infant death syndrome (SIDS) is NOT an indication for apnea monitoring, and it cannot be used to diagnose obstructive sleep apnea.
After setting up a 12-lead ECG on a patient and verifying that the leads are connected properly, you note a "noisy" and unstable signal. To resolve this problem you would:
- deactivate/turn off the electronic noise filter
- change the paper/scan speed to 50 mm/second
- confirm that the patient is staying motionless
- change the calibration to 5 mm/millivolt
A "noisy" ECG signal is usually due to either patient motion or bad electrical connections. If due to movement, make sure the patient remains motionless during the recording. If the patient is still, check and confirm that: (1) the ECG lead snaps are clean and corrosion-free; (2) the lead electrodes are connected properly to the patient; (3); the electrode gel is not dry (replace suspect electrodes); and (4) the main lead cable is undamaged. If the connections checkout, make sure that the device's electronic noise filter is ON.
A patient has a peak expiratory flow rate (PEFR) of 5.2 L/sec before bronchodilator treatment and 6.3 L/sec after treatment. What percent change in PEFR occurred?
% change = [(post – pre) / pre] × 100
% change = [(6.3 – 5.2) / 5.2] × 100 = 21%
Which of the following alarm limits would be appropriate for setting on an apnea monitor being used on a neonate being discharge to the home setting?
- apnea limit 20 seconds; low/high heart rate 40 to 120/min
- apnea limit 60 seconds; low/high heart rate 80 to 220/min
- apnea limit 20 seconds; low/high heart rate 80 to 220/min
- apnea limit 40 seconds; low/high heart rate 80 to 120/min
Most modern apnea monitors designed for home use has a setup program by which you provide patient and time/date information and set the alarm and event limits. The most common settings for neonates are: (1) an apnea alarm limit of 20 seconds and (2) a low/high heart rate range of 80-220/min.
A patient breathing 100% O2 has a P(A-a)O2 of 400 torr. What is her approximate % shunt?
In estimating the percent shunt, with the FIO2 = 1.0 (100% O2), every 100 torr P(A-a)O2 equals about a 5% shunt. In this case, you would estimate the %shunt as 400/100 = 4 x 5 = 20%.
A doctor asks you to provide serial measures of the respiratory muscle strength of a patient with a progressive acute neuromuscular disorder. Which of the following measures would you select to provide the needed information?
- forced vital capacity
- arterial blood gas results
- rapid shallow breathing index
- maximum voluntary ventilation
Of the measures listed, only the forced vital capacity provides information primarily on the patient's respiratory muscle strength. Since the forced vital capacity includes both a maximum inspiratory and expiratory effort, it provides an overall picture of the strength of both these muscle groups. Were separate information needed on either the inspiratory or expiratory muscles alone, a maximum inspiratory (MIP) or maximum expiratory pressure (MEP) could be measured instead.
When performing spirometry on an adult patient, which of the following would indicate invalid/unacceptable test results?
- back extrapolated volume 300 mL
- time to peak flow 100 msec
- forced expiratory time > 6.0 sec
- repeat FVCs match within 150 mL
Validity checks recommended to ensure a valid patient effort include: (1) a back extrapolated volume < 150 mL; (2) a time to peak expiratory flow < 120 msec; (3) a forced expiratory time > 6.0 seconds with the change in exhaled volume during the last 0.5 sec of the maneuver < 100 mL; and (4) all repeat FEV6 values matching within 150 mL.
Which of the following is being measured if you instruct a patient to take a maximum deep breath and then exhale completely?
- inspiratory force
- vital capacity (VC)
- total lung capacity (TLC)
- residual volume (RV)
The vital capacity or VC is obtained by measuring measured the total amount of air that can be exhaled after a maximum inspiration. The VC is the sum of the inspiratory reserve volume, the tidal volume, and the expiratory reserve volume (IRV + VT + ERV).
For continuous monitoring of an adult patient's oxygen saturation with a pulse oximeter, which of the following LOW alarm limits would be appropriate?
For continuous monitoring of a patient's oxygen saturation with a pulse oximeter, you should set the low alarm limit according to your institution's protocol, but generally no lower than 92%. A higher setting will likely results in many false alarms, while a lower setting can result in the patient becoming hypoxemic before the alarms sounds (a SpO2 of 92% corresponds to a PaO2 of about 65 mm Hg).
When performing a modified Allen test on the left hand of a patient, you note that her palm, fingers, and thumb remain blanched for over 15 seconds after releasing pressure on the ulnar artery. You should:
- use the brachial site for sampling
- sample from the contralateral radial artery
- use the femoral site for sampling
- perform the Allen test on the right hand
The results of the initial Allen test indicate collateral circulation on the left hand. The therapist should repeat the Allen test on the right hand and proceed accordingly.
To validate patient readings obtained from a transcutaneous blood gas monitor, you should:
- measure and compare the PtcO2 and PtcCO2 at three or more different sites
- compare the monitor's readings to a concurrent pulse oximetry reading
- compare the monitor's readings to those obtained via a concurrent ABG sample
- compare the patient reading to those obtained when calibrating the sensor
Once properly set-up, the clinician should compare the transcutaneous blood gas monitor's readings to those obtained via a concurrent arterial blood gas. Good consistency between values validates monitor performance under the existing conditions.
You are assisting a nurse in ICU measure a patient's central venous pressure (CVP) with a strain-gauge pressure transducer. You note that the pressure transducer is positioned well above the middle of the patient's lateral chest wall. What effect if any would this have on the CVP measurement?
- it would not affect the measurement
- it would underestimate the CVP
- it would cause damping of the signal
- it would overestimate the CVP
When measuring vascular pressure such as central venous, pulmonary artery or capillary wedge pressures, it is essential that you ensure that the base of the fluid column or pressure transducer is positioned at a level equal to the point of measurement, i.e., the right atrium (also called the phlebostatic axis). Otherwise, the system will behave like a U-tube manometer and overestimate pressures if placed too low, or underestimate pressures if placed too high.
Significant overinflation of an endotracheal tube cuff may cause which of the following?
- silent aspiration
- mucosal ischemia
- air leakage
Overinflating the cuff of an endotracheal tube (above 30 cm H2O) can decrease or occlude capillary blood flow, resulting in mucosal ischemia and tissue damage to the tracheal wall. Air leakage and 'silent' aspiration of pharyngeal secretions are complications of LOW cuff pressures, i.e., below 20 cm H2O.
Which one of the following measures could be used to assess changes in exercise tolerance associated with participation in a pulmonary rehabilitation program?
- pre- and post-resting minute ventilation
- pre- and post-peak expiratory flow rates
- frequency and duration of hospitalizations
- pre- and post-6 minute walking distance
Measures useful in assessing changes in exercise tolerance due to participation in a pulmonary rehabilitation include: pre- and post 6 or 12 minute walking distance; pre- and post-pulmonary exercise stress test; review of patient home exercise logs; strength measurements; and performance on specific exercises (e.g., ventilatory muscle, upper extremity).
You are monitoring a patient with myasthenia gravis and finds that the maximum inspiratory pressure (MIP/NIF) has changed from -35 cm H2O 4 hours ago to -10 cm H2O. Based on this change, you should recommend which of the following?
- measuring maximum voluntary ventilation (MVV)
- administering oxygen via partial rebreathing mask
- administering oxygen via nasal cannula at 5 L/min
- obtaining an arterial blood gas analysis
A rapid decrease in MIP/NIF indicates that the disease has progressed to affect the respiratory muscles. If severe, this can cause hypoventilation and respiratory acidosis. To confirm this, an arterial blood gas should be drawn.
Which of the following specialized imaging tests would be most useful in diagnosing a pulmonary emboli?
- anterior-posterior chest radiograph
- pulmonary function test (PFT)
- ventilation-perfusion scan (V/Q scan)
- arterial blood gas (ABG)
A chest X-ray and an ABG might be useful in detecting an abnormality, but not specifically a pulmonary emboli. Pulmonary function testing (PFTs) may reveal abnormal flows and volumes but not the perfusion problems cause by pulmonary embolization. A V/Q scan would show a lack of blood flow due to emboli in the blood pulmonary circulation. CT angiography is another toll useful in diagnosing pulmonary emboli.
The best way to determine the proper CPAP level for an individual patient is to:
- assess the apnea-hypopnea index at different CPAP levels during a sleep study
- have the patient keep a log of sleep problems at different CPAP levels
- measure and record the patient's SpO2 continuously throughout sleep
- have the patient's spouse keep a log of sleep problems at different CPAP levels
The proper CPAP level for a given patient is determined by one of several methods. The most common method is to repeat the sleep study, using different levels of CPAP, i.e., a titration study. Observed changes in the apnea-hypopnea index (AHI) are then correlated with the various CPAP pressures. The prescribed level of CPAP is the lowest pressure at which apneic episodes are reduced to a normal frequency and duration.
Due to her patient's minimal response to the standard prescription for an aerosolized bronchodilator, a doctor asks your advice on how best to adjust the dosage. You would recommend:
- peak expiratory flow rate monitoring
- helium dilution functional residual capacity
- carbon monoxide diffusing capacity
- pre/post bronchodilator spirometry
At this stage in the patient's management, the best way to determine if a change in dose, frequency, or medication is needed for this patient would be pre/post bronchodilator spirometry. Peak expiratory flow rate monitoring is used primarily to assess asthma patients' airway tone over time, whereas helium dilution functional residual capacity is used mainly to quantify the degree of hyperinflation or differentiate obstructive from restrictive disorders.
You detect an irregular pulse and pulse deficit in a patient by palpation and auscultation, and suspect atrial fibrillation as the cause. Which of the following tests would you recommend to confirm if atrial fibrillation is the problem?
- cardiac catheterization
- coronary angiogram
You should recommend obtaining an electrocardiogram to screen for heart disease, rule out heart disease in surgical patients, evaluate patients with chest pain, follow the progression of patients with CAD, and evaluate heart rhythm disorders, such as atrial fibrillation.
A doctor suspects that a patient's asthma-like symptoms are due to airway hyperreactivity. She asks your advice on the best way to confirm this diagnosis. You would recommend:
- peak expiratory flow rate monitoring
- bronchial provocation testing
- carbon monoxide diffusing capacity
- pre/post bronchodilator spirometry
Bronchial provocation testing (e.g., methacholine challenge testing) is used to confirm or exclude a diagnosis of airway hyperreactivity. It also may be used to determine the relative risk of developing asthma, evaluate patients for occupational asthma, and assess the response to therapeutic interventions.