# 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
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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
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.
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.
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.
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
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.