SCC E.R. Ch 4 Evaluate Proc. Results

A patient has a minute volume of 8.25L/min and is breathing at a rate of 22 breaths/min. What is his average tidal volume?
1. 182ml
2. 375ml
3. 275 ml
4. 435 ml
Click the card to flip 👆
1 / 33
Terms in this set (33)
A patient has a minute volume of 8.25L/min and is breathing at a rate of 22 breaths/min. What is his average tidal volume?
1. 182ml
2. 375ml
3. 275 ml
4. 435 ml
2. VT= 8.25 ÷ 22=0.375l or 375ml
At a normal venous blood PaO2 of 40 torr, what is the approximate percent saturation of hemoglobin with oxygen?
1. 0.4
2. 0.87
3. 0.73
4. 0.66
3. The affinity of Hb for O2 varies according to PO2, as described by the S-shaped oxyhemoglobin dissociation curve. At a venous PO2 of 40 torr, Hb saturation is about 73% (you can apply the "40-50-60/70-80-90" rule of thumb to this question, I.E., PO2S of 40, 50 and 60 torr correspond respectively to saturations of about 70%, 80% and 90%). Because the curve at this point is steep, a given drop in PO2 causes a large drop in saturation, indicating a weak affinity for O2. This decreased affinity for O2 at low PO2S helps release large amounts of O2 to the tissues in response to small drops in PO2
What conclusions can you draw from the following data, obtained on a 47 year old 55kg female patient admitted for pulmonary complications arising from kyphoscoliosis:
ACTUAL PREDICTED % PRED
TLC 3.13 4.10 76%
FRC 1.44 1.96 73%
RV 0.85 1.09 77%
VC 2.28 2.93 78%
FVC 2.28 2.92 78%
FEF 200-1200 4.32 4.48 97%
FEF 25-75 2.83 2.74 103%
1. Results indicate generalized airway obstruction
2.results indcate a restrictive lung disorder
3. results indicate normal pulmonary function
4. rsults indcate poor patient effort during the test
2. With all lung volume less than predicted (includign the FVC), but normal expiratory flows, this patient has a restrictive disorder, consistent with her history of Kyphoscoliosis.
A patient with a history of nocturnal dyspnea has a FEV1 of 1.5L before bronchodilator therapy and a FEV1 of 1.8L fifteen minutes after treatment. These results indicate that the patient
1. has airway obstruction that is unresponsive to treatment
2. is suffering from a combined obstructive and restrictive disorder
3. has a at least partially reversible airway obstruction
4. is developing tolerance to the bronchodilator.
3. The percent change in the FEV1 is +20%([1.8-1.5]/1.5=0.31/1.5=.20=20%). An increase in FEV1 of more than 12-15% between pre and post-bronchodilator therapy indicates the presence of at least partially reversible airway obstruction.
A patient recieving 30% O2 has a PaO2 of 66 torr and PaCO2 of 32 torr. Which of the following best describes this patient's oxygenation status?
1. A mild disturbance of oxygenation consistent with hypoventilation
2. A mild disturbance of oxygenation consistent with a V/Q imbalance
3. A moderate disturbance of oxygenation consistent with acute lung injury
4. A severe disturbance of oxygenation consistent with ARDS
2. The patient is hyperventilating so hypoventilation can be ruled out. The P/F ratio is 220 (66/.3) P/F ratios between 200-300 indicate mild distrubanceds of oxygenation, usually due to V/Q imbalances. Ratios between 100 and 200 indicate a moderate disturbance due to shunting, consistent with acute lung injury. A P/F <100 indicates a severe disturbance of oxygenation/severe shunting consistent with ARDS.
On reviewing an ECG print-out you note widen QRS complexes. Which of the following is the most likely cause of this problem?
1. atrial fibrillation
2. 1st degree heart block
3. sinus arrhythmia
4. bundle branch block
4. the duration of a normal QRS complelx is 0.12 seconds (3small boxes) or less. Causes of a widened QRS complex include right or let bundle branch block (BBB), hyperkalemia, ventricular pre-excitation (e.g. Wolf-parkinson-White pattern), and any ventricular rhythm, including those caused by a ventricular pacemaker.
Which of the following exercise test findings (as compared to normal) is most consistent with exercise intolerance primarily to aventilatory impairment?
1. normal aterial PaO2
2. increased max O2
3. increased arterial PaCO2
4. normal max heart rate
3. Exercise intolerance due to a ventilatory impairment usually manifests as a decrease in VO2 max, maximum heart rate, maximum cradiac output, and PaO2 with increase in PaCO2 and teh VE/VCO2 ratio during exercise evaluation. The O2 pulse, cardiac output/VO2 ratio and ventilatory (anaerobic)threshold may remain normal.
In performing a patient-ventilator check you note that the expiratory portion of the flow-volume loop does not return to baseline. Which of the following is the most likely problem?
1. decreased compliance
2. air leak
3. auto-PEEP
4. overdistension
3. The presence of auto-PEEP can be visualized on a ventilator's graphic display when flow does not return to the baseline before the start of the next breath. Either a flow vs. volume loop or a flow vs. time scalar will reveal this pattern.
A patient has a body surface area (BSA) of 2.0m2 and a cardiac output (CO) of 3.0L/min. what conclusions can you draw regarding the patient's cardiac index?
1. the patient's cardiac index is below normal
2. the patient's cardiac index is normal
3. the patien'ts cardiac index is above normal
4. insufficient data to compute the cardiac index
1. Cardia index (CI)=CO/BSA. in this case CI=3.0/2.0= 1.5L/min/m2. Because a normal range for cardiac index is 2.5-5 L/min/m2, this patient's cardizc index is below normal.
Teh results of a an arterial bood gas analysis for a patient breathing 100% oxygen are below
pH7.24 PaCO2 38torr HCO3 23m Eq/LBE -1
PaO2 610 torr SaO2 100%
Which of the follwing is the likely problem?
1. respiratory acidosis
2. large physiologic shunt
3. metabolic acidosis
4. laboratory error
4. In terms of oxygentation, a PaO2 of 610 torr on 100% O2 is not only possible, but near normal (based on the alveolar air equation). ON the other hand, the acid base values are not consistent with the underlying relationship that determines pH (the Henderson-Hasselbach equation) In this case both the PaCO2 and HCO3 are normal. With both these values being within the nromal range, the pH also would have to be close to normal which it clearly is not (pH=7.24) The only possibility here is a lab error.
AFter bedside measurement, you note that a patient's slow and forced vital capacity fare approximtely equal and both are less than 60% of the predicted values. Which of the floolowing diagnoses is Least likely? 1. lung resection 2. interstila fibrosis 3.myasthenia gravis 4. COPD4. if the slow vital capacity is low, a restrictive disorder is likely present, eg interstitial fibrosis, lung resection, consolidative processes, congestive heart failure, obesity, and neuromuscular disorders such as myasthenia gravis. In these patients the slow VC and FVC will not usually differ significantly. If the FVC is substantially less than the slow vital capacity air trapping is likely present, signifying obstructive lung disease.As compared to predicted normals, a patient has a normal FEV1%, normal FEF25-75, but a makedly reduced FVC. Test results are repeatable. Which of the following is the most likely underlying problem? 1. Poor patient effort during the test procedure 2. a restrictive disorder of the lungs or chest wall 3. combined restrictive and obstructive disease 4. peripheral (small) airway obstruction2. in the presence of normal expiratory flow parameters (such as the FEV1% and FEF 25-75), a reduced FVC indicates a restrictive disorder of the lungs or chest wall.A patieint is recieving volume control A/C ventialtion. Teh patient has become increasingly agitated and the end-tidal CO2 has decreased from 39 to 28torr over the last 2 hours. Which of the following is the most likely cause? 1. increased cardiac output 2. mainstem intubation 3. high body temp.4. the most likely cause of this patient's low end tidal CO2 is hyperventiation caused by the patient's agitation. Treating the cuase of the agitation may restore ventilation and thus normalize end tidal CO2. High body temp (fever) increased metabolism and would tend to increase, not decrease expired CO2 levels. Mainstem intubation normally does not affect capnographic readings.An unconcscious patient admitted to the E.D. has a SpO2 of 94% but analysis of an arterial sample on a CO oximeter reveals a SAO2 of 69%. Which of the following problems is most likely? 1. carbon monoxide poisoning 2. opiate drug overdose 3. diabetic ketoacidosis 4. acute pulmlnary edema1. the most likely problem is carbon monoxide poisoning. Most standard two wavelength pulse oximeters cannot detect HbCO. On the other hand, multi wavelength CO oximetry can detect the presence of abnormal hemoglobins, such as HbCO and met Hb and thus provide an accurate measure of the SaO2. A further clue in this case is that the patient is unconscious. HbCO levels over 20-25% (as likely in this case)often will cause a loss of consciousness.A 48 yr old 180lb male is orally intubated receiving mechanical ventilation with a 6.0 tube secured in place, which requires a cuff pressure of 38cm H2O to prevent significant volume loss. which of the following actions would be appropriate in this case? 1. replace the endotracheal tube with a smaller size 2. accept the large volume loss during inspiration 3. replace the ETT with a larger size 4. deflate and reinflate the cuff with 20 ml air3. the most common cause of high ET tube cuff pressures being needed to obtain a seal is that the tube is too small for patient's airway. You should suggest reintubating the patient with a larger endotracheal tube in order to prevent excessive cuff pressures and mucosal damage.A patient undergoing CPAP titration for sleep apnea exhibits prolonged periods of central sleep apnea during the procedure, even at a baseline pressure of 15cm H2O. Which of the following would you recommend for this patient? 1. titrate the CPAP pressure up to 20cmH2O and reassess 2. discontinue the titration and recommend a triall of a xanthine 3. consider a trial of bi-level positive pressure 4. switch to an auto-CPAP unit and continue the titration3. If during CPAP titration (1) the patient cannot tolerate high CPAP pressure, (2) there are continued obstructive respiratory events at higher levels of CPAP(>15cmH2O), or (3) the patienty exhibits periods of central sleep apnea during titiraiton, you should consider a trial of BiPAP, starting at EPAP =4cmH2O and IPAP=8cmH2OAs measured by the single breath DLco method, the diffusing capacity of the lungs would be decreased in which one of the following cases? 1. pulmonary hypertension 2. secondary polycythemia 3. strenous exercise 4. pulmonary emphysema4. The DLco is low in conditions that actually impair membrane diffusion (as in pulmonary fibrrosis) or decrease surface area (as in empysema). The DLco can also be less than normal with reduced Hb (as in anemia), decreased pulmonary capillary blood flow, or decreased alveolar volume. Increases in DLco occur with increased Hb (as in seconday polycythemia), increased pulmnary blood flow, increase alveolar volume and during exercise.Aj patient's mixed venous PO2 has decreased from 41 mmHg to27mm Hg over the last hour. What is the most likely explanaiton for this change? 1. the blood sample was withdrawn too rapidly 2. the patient's temperature 3. a pulmonary diffusion defect is developing 4. the patient's cardiac output has decreased4. Venous oxygenation parameters indicate the adequacy of tissue oxygenation relative to blood flow. The drop in PvO2 from a normal value of 41mmHg to 27 mmHg(abnormally low) indicates inadequate perfusion realtive to tissue needs, as usually caused by a significant decrease in cardiac output. A diffusion defect would lower arterial oxygen parameters, while withdrawing blood too rapidly via a pulmonary artery catheter would reult in falsely high levels of mixed venous oxygen.A post op patient is receiving volume control A/C ventilation at the rate of 12/minute with 5cmH20 PEEP. With the ventilator settings unchanged, you measure and record the following data: 1000 1200 1400 1600 PIP 18 20 22 26 PPlat 15 16 16 16 Dynamic Cl 42 41 39 34 Static Cl 55 56 55 54 These changes indicate which of the following? 1. increased airway resistance 2. decreased airway resistance 3. increased lung compliance 4. decreased lung compliance1. The PIP is steadily rising, while the plateau pressure (and plateau-PEEP) remains relatively constant. Thus it is the difference between PIP and Plateau pressures that is increasing. Because the difference between PIP and plateau pressures is the pressure due to flow resistance, the patient airway resistance (RAW) must be increasing.You obtain an SpO2 measurement on a patient of 80%. Assuming this is an accurate measure of hemoglobin saturation, what is the patient's approximate PaO2? 1. 40 torr 2. 50 tprr 3. 60 torr 4. 70 torr2. The rule of thumb used to equate hemoglobin saturation to PO2 is 40-50-60 (PO2)=70-80-90(SpO2) With a SpO2 of 80%, this patient's PO2 would be approximately 50 torr (mmHg)A patient is receiving volume control A/C ventilation. Which of the following changes would occur if the patient's compliance were to decrease? 1. the expiratory time will increase 2. the flow rate will decrease 3. the system pressure will increase 4. the delivered volume will decrease3. When faced with either a decrease in compliance or /and an increase in resistance, a ventilator operating in the volume control mode will deliver a constant volume, but at a higher system pressure. Delivered volume will decrease only if a preset pressure limit causes the ventilator to prematurely end inspiration.Upon reviewing the patient's chart, results of a chest x-ray indicate:"complete opacificaiton of the left chest with a shift of the trachea and mediastinum to the left." These findings are most consistent with which of the following? 1. pneumothorax of the right lung 2. atelectasis of the left lung 3. diffuse pulmonary emphysema 4. right-sided pleural effusion2. Opacification of lung tissue on -x-ray occurs due to consolidation or atelectasis. Moreover, if the area affected is large the trachea and mediastinum tend to shift towards the area of collapse, as seen here. Pneumothorax would cause hyperlucency on the affected side, with emphysema also showing hyperlucency, but more generally throughout all lung fields. Effusion is generally visualized on upright or sitting x-ray as affectiving only the basal areas, obscuring the costophrenic angle.Based on the following blood gas report, what is the most likely acid=base diagnosis? pH= 7.20 PCo2=51 torr HCO3= 19.5mEq/L 1. acute(uncompensated) respiratory acidosis 2. combined respiratory and metabolic acidosis 3. partially compensated metabolic acidosis 4. partially compensated respiratory acidosis2. The pH is low, indicating acidosis. The PCO2 is high, indicating hypoventilation and a respiratory acidosis. The low HCO3 indicates a metobolic acidosis. Since both the high PCO2 and low HCO3 are contributing to the low pH, the problem is a combined respiratory and metabolic acidosis.Prior to drawing an arterial blood sample, you note that a patient has significantly elevated prothrombin and partial thromboplastin times (PT and PTT). Which of the following actions would be appropriate in this situation? 1 obtain a venous sample instead of an arterial one 2 allow extra time after the procedure to assure hemostasis 3 use extra heparin in preparing the sampling syringe 4switch to a larger bore (18g) needle to obtain the sample2 High PTs and PTTs indicate abnormally slow clotting, in whchi case exgra time should be provided after the procedure to assure hemostasis at the puncture site.While performing a patient ventilator check you note the following settings and parameters: Exhaled tidal volume=650ml Peak inspiratory pressure 35cmH2O High pressure limit 60cmH2O Low pressure limit 20cmH2O Which of the following changes would you make 1. decrease the high pressure limit to 45-50 cmH2O 2. increase the set tidal volume to 800ml 3. decrease low pressure alarm to 5cmH2O 4. increase the low tidal volume alarm to 600 ml1. All alarm/limit settings in this example are acceptable except the high pressure limit, which should be set 10-15 cmH20 above the peak inspiratory pressure, in this case to 45-50 cmH2O.You see a patient recieving control mode ventilation "bucking" the ventlator with accessory muscles use and ribcage-abdominal paradox clearly visible. This will result in: 1. decreased ventilatory drive 2. increased physicologic 3. increased work of breathing 4. acute respiratory alkalosis3. control mode ventilation is poorley tolerated by most patients, often resulting in asynchronous breathing efforts and other signs of respiratory distress. Patient ventilator assyncrhony increased the work of breathing, and with it, th oxygen consumption of the respiratory muscles. It is for this reason that sedation or paralysis is often required when controlled ventilation is necessary. If possible a different mode of ventilation should be considered.Which of the following describes the correct procedure for performing a modified Allen's test? 1. compress both the radial and ulnar arteries then release the radial artery 2. compress both the radial and ulnar arteries then release the ulnar artery 3. compress both the radial and ulnar arteries tehn release both arteries at once 4. compress the brachial artery only and observe circulation to the hand2. to perform the modified Allen's test, 1) the patient clenches his hand into a tight fist while you apply pressure to both the radial and ulnar ateries 2) the patient then opens his hand without fully extending it(the palm and fingers are blanced) 3)you maintain pressure on the radial artery while removing pressure on the ulnar artery. At this point you should o serve flushing of the entire hand, indciating the presence of collateral circulationWhich of the following patients has the most serious problem with adequacy of oxygenation? Patient FiO2 PaO2 A 1.00 85 B 0.70 90 C 0.40 95 D 0.28 65 1.A 2. B 3. C 4. D1. Patient A, with a Pao2 of 85mmHg breathing 100% O2 has the most serious oxygenation problem. This equates to a PaO2/Fio2 (P/F) ratio of about 85, well below the 200 threshold indicating a severe impairment in oxygenation. Patinet B has a P/F ratio of about 130, also unacceptable but not quite so bad. Patients C and D all have P/F ratios greater than 200.Which of the following can be used to assess a patient's response to oxygen therapy? 1. blood gas analysis 2. pulse oximetry 3. patient inspection A. 1,2,and 3 B. 2 and 3 C. 1 and 3 D. 1 and 2A. Once the desired amount of O2 is being given, the patient's response shold be assessed. Depending on the objectives, assessment may include observation, inspection, analysis of arterial blood gases or pulse oximetry. If the response indicates that the objectives are not being met, then the amount of O2 being given should be adjusted and patient reevaluatedTo avoid thermal injury with transcutaneous blood gas monitor sensors, what should you do? 1. place sensor over thick skin areas 2. apply hydrocortisone cream under the sensor 3. regulary rotate the sensor site 4. calibrate sensor q4h3. Because the transcutaneous blood gas monitors sensor is heated, you must take care to avoid thermal injury to the patient's skin. This is accomplished by 1)careful monitoring of sensor temperature(the upper safe limit is around 42 degrees C) and 2) rotating the sensor site on a regular basis, usually every 2-6 hours (depending on the patinet).All of the following are true regarding capillary blood gas sampling except: 1. capillary sampling can be used in lieu of direct arterial access in 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 levels2 Capillary blood gas sampling is sometimes used as an alternative to direct arterial access in infants and small children. Properly obtained capillary blood from a well perfused patient can provide rough estimateds of arterial pH and PCO2 levels. However, the capillary PO2 is of no value in estimating arterial oxygenation. For this reason direct arterial access is still teh preffered approach for assessing gas exchange in infants and small children. Clinicians should exercise exreme caution when using capillary blood gases to guide clinical decisions.While doing a ventilator check on a patient receiving volume-controlled ventilation you observe a substantial drop in pressure on the pressure vs. time waveform after triggering of most machine breaths. Which of the following best explains this finding? 1. improper sensitivity setting 2. presence of auto-PEEP/air trapping 3. a leak in the patient ventilator system 4. inadequate inspiratory flow setting4. A drop in pressure (scalloping) after triggering a volume-controlled breath usually indicates inadequate inspiratory flow. Normally, pressure should rise after inspiration begins. To correct this problem increase the inspriatory flow until the scalloping of the pressure waveform diasppears. improper/inadequate sensitivity would appear as a >1 to 2 cmH2O drop in pressure before breath triggering.What percent decrease in FEV1 needs to occur to conclude that a methalcholine challenge is positive for airway hyperreactivity? 1. 0.1 2. 0.15 3.0.23. The methacholine challenge assesses changes in airway caliber with increasing concentrations of methacholine. Patinets with hyperreactive airways will show early changes at low doesages. A 20% decrease in FEV1 is considered a positive result. The methacholine concentration at which a 20% decrease in FEV1 occurs is called the provocative concentration, or PC20. The lower the PC20 the worse the airway hyperreacitivy.