Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
106 Cards in this Set
- Front
- Back
|
RE01 [Mar96]
Which of the following is a normal characteristic of lung? A. 3,000,000 alveoli B. Alveolar diameter 3 mm C. External surface area: 10 m2 D. Alveolar surface area: 5 to 10 m2 E. None of the above |
RE01 [a] Which of the following is a normal characteristic of lung?
A. 3,000,000 alveoli – No, 300 million B. Alveolar diameter 3 mm – No, average 0.2mm C. External surface area: 10 m2 – seems too large D. Alveolar surface area: 5 to 10 m2 – No, 50-100m2 E. None of the above – Correct |
|
|
RE02 [Mar96] [Mar99] [Apr01]
A young man collapses one lung. His ABGs on room air would be: A. pO2 80, pCO2 50 mmHg B. pO2 50, pCO2 80 mmHg C. pO2 50, pCO2 50 mmHg D. ? |
RE02 [agk] A young man collapses one lung. His ABGs on room air would be:
A. pO2 80, pCO2 50 mmHg B. pO2 50, pCO2 80 mmHg C. pO2 50, pCO2 50 mmHg D. ? None of these is ideal. The pCO2 should be normal or lower in a normal ‘young man’ who’s brainstem is working normally… combination of increased VA to blow off CO2 plus the shunt causing hypoxia, further increasing ventilation |
|
|
RE02 [Jul96]] [Mar97]
The ABGs in a healthy young 70kg male with one collapsed lung are: A. paO2 50 mmHg, pCO2 25 mmHg B. paO2 95 mmHg, pCO2 40 mmHg C. paO2 60 mmHg, pCO2 45 mmHg D. paO2 60 mmHg, pCO2 25 mmHg |
RE02b [c] The ABGs in a healthy young 70kg male with one collapsed lung are:
A. paO2 50 mmHg, pCO2 25 mmHg B. paO2 95 mmHg, pCO2 40 mmHg C. paO2 60 mmHg, pCO2 45 mmHg D. paO2 60 mmHg, pCO2 25 mmHg – Probably Correct (pO2 of 90 probably a bit too high) see Question AB11 |
|
|
RE03b [Jul00]
Pulmonary vascular resistance is increased in : A. Increase in pulmonary arterial pressure B. Hypocarbia C. Alkalosis D. Increased left atrial pressure E. Hypoaxemia |
ANSWER E
A. Increase in pulmonary arterial pressure – No this has minimal effect due to recruitment & distension B. Hypocarbia – No, this decreases HPV – therefore decreases PVR C. Alkalosis – No, this decreases HPV – therefore decreases PVR D. Increased left atrial pressure – No, decreases due to recruitment & distension E. TRUE |
|
|
RE04 [Mar96] [Jul97] [Jul02]
The greatest increase in (?physiological) dead space would be expected with: A. Pulmonary embolism B. Atelectasis (or: collapse of one lung) C. Pneumothorax D. Bronchoconstriction E. Obesity (see also RE08 & RE20) |
RE04 [ad] The greatest increase in (?physiological) dead space would be expected with:
A. Pulmonary embolism – Correct B. Atelectasis (or: collapse of one lung) – No, this would be an intrapulmonary shunt C. Pneumothorax – No, this would be a shunt, but it would be minimal anyway due to HPV D. Bronchoconstriction – No, increased shunt fraction E. Obesity – No, decreased FRC |
|
|
RE05 [Mar96] [Jul00] [Apr01] [Jul01] [Jul02] [Feb04]
As go from the top of the erect lung to the bottom: A. Water vapour pressure remains constant B. pN2 remains constant C. pCO2 at apex is higher than at the base D. pO2 at base is lower than at the apex E: V/Q is higher at base than apex F. Ventilation goes up as go up lung G. Compliance is more at base than apex |
RE05 [ajkl] As go from the top of the erect lung to the bottom:
A. Water vapour pressure remains constant - – Correct B. pN2 remains constant – No, the partial pressure changes C. pCO2 at apex is higher than at the base – No, lower (higher V/Q at apex) D. pO2 at base is lower than at the apex – Hmm… yes this is correct also (Apex=132 , Base = 89) E: Difference in V/Q ? – Correct, but… what is the question/answer really stating (Apex=3.3 , Base=0.6 F. Ventilation goes up as go up lung – No, decreases G. Compliance is more at base than apex – At FRC yes, but what is the starting volume? Edit: only correct answer is G! |
|
|
RE03 [Mar96] [Mar99] [Feb04]
Pulmonary vascular resistance: A. Is minimal at FRC B. ?Increases/?decreases with increase in lung volume C. Increases with elevated CVP D. ? |
RE03 [ag] Pulmonary vascular resistance:
A. Is minimal at FRC – Yes, this is one of the important points of FRC B. ?Increases/?decreases with increase in lung volume C. Increases with elevated CVP D. ? |
|
|
RE06 [Mar96] [Mar99] [Jul01]
Distribution of pulmonary ventilation & perfusion in the erect position: A. Gradient of change in ventilation is greater than that for perfusion B. Ventilation increases as go up the lung C. Perfusion increases as go up the lung D. V:Q ratio at apex is greater than at base E. None of the above |
ANSWER D
A. Gradient of change in ventilation is greater than that for perfusion – No, other way around B. Ventilation increases as go up the lung – No, decreases C. Perfusion increases as go up the lung – No, decreases D. V:Q ratio at apex is greater than at base – Correct E. None of the above |
|
|
RE07 [Mar96]
Oxygen unloading: A. Increases with increased paCO2 B. Decreases with increase in temperature C. Decreases with increase in 2,3 DPG D. ? |
ANSWER A
|
|
|
RE08 [Mar97]
Alveolar dead space: A. Is less than physiological dead space B. Is decreased with mechanical ventilation C. Is increased with hypotension |
RE08 [c] Alveolar dead space:
A. Is less than physiological dead space – Yes, by definition B. Is decreased with mechanical ventilation – No, increased C. Is increased with hypotension – Yes, to a point, but not just ANY hypotension… (See Cooper, p14) – other causes (erect posture, IPPV, age, volatile anaesthetic agents). This is because of the possibility of developing West Zone 1 areas in the lung… |
|
|
RE08b [Jul98] [Jul99] [Feb00] [Jul02]
Alveolar dead space is increased with: A. Pleural effusion B. CCF C. Pneumothorax D. Hypotension E. None of the above |
ANSWER D
A. Pleural effusion – No, reduced B. CCF – Yes, possibly from impairment of diffusion… C. Pneumothorax – No, reduced D. Hypotension – Yes: increased west zone 1, B increases west zone 3 and decrease west zone 1 E. None of the above |
|
|
RE09 [Mar97] [Jul97] [Mar99] [Jul00] [Jul01]
If dead space is one third of the tidal volume and arterial pCO2 is 45 mmHg, what is the mixed expired pCO2? A. 20 mmHg B. 25 mmHg C. 30 mmHg D. 45 mmHg E. 60 mmHg |
ANSWER C
|
|
|
RE10 [Mar97] [Jul98] [Mar99] [Jul00] [Jul01] [Mar03] [Jul03]
With constant FIO2, CO and VO2, an increase in mixed venous O2 content would be seen with: A. Hypothermia B. Increased paCO2 C. Decreased 2,3 DPG D. Alkalosis E. None of the above |
RE10 [cfgjl] With constant FIO2, CO and VO2, an increase in mixed venous O2 content would be seen with:
A. Hypothermia – No. This would be true if the metabolic rate is decreased (ie. Decreased O2 requirement), but it is likely to be increased (thermoregulation) B. Increased paCO2 - No C. Decreased 2,3 DPG – No, the extraction is the same D. Alkalosis – No, the extraction is the same E. None of the above - Correct The key word here is CONTENT |
|
|
RE11 [Jul97] [Jul01]
With altitude: A. Increased 2,3 DPG B. Increased oxygen unloading in peripheries C. Increased oxygen uptake in the lungs D. ? E. ? |
RE11 [dl] With altitude:
A. Increased 2,3 DPG – Correct, but this is actually counterproductive when you think about it B. Increased oxygen unloading in peripheries - No C. Increased oxygen uptake in the lungs – No D. ? E. ? |
|
|
RE11b
In acclimatisation to altitude: A. P50 is reduced, improving O2 uptake in the lungs B. P50 is increased, improving O2 offloading in the tissues C. 2,3 DPG levels are reduced, improving O2 offloading in the tissues D. Alkalaemia reduces the affinity for O2, increasing p50 E. Increase in 2,3 DPG and a decrease in P50 |
RE11b In acclimatisation to altitude:
A. P50 is reduced, improving O2 uptake in the lungs – No, the ODC is right shifted by increase 2,3-DPG (which is offset by the alkalosis to a degree) B. P50 is increased, improving O2 offloading in the tissues – No, overall it is decreased C. 2,3 DPG levels are reduced, improving O2 offloading in the tissues – No, increased D. Alkalaemia reduces the affinity for O2, increasing p50 – No, increases the affinity (reducing p50) E. Increase in 2,3 DPG and a decrease in P50 – Yes and yes… the net effect on the ODC (by 23DPG & CO2) is to cause a net shift of the ODC to the left with acclimatisation Edit: with moderate altitude, only 2,3DPG and R shift, but with extreme altitude hyperventilation and hypocapnia,a left shift occurs, decreasing P5O and increasing 2,3DPG! |
|
|
RE11c
With acute acclimitisation to altitude: A. Hypoventilation B. Decreased cardiac output C. Pulmonary oedema D. Polycythaemia E. Increase in 2,3 DPG |
RE11c With acute acclimitisation to altitude:
A. Hypoventilation – No, hyperventilation B. Decreased cardiac output – No, increased C. Pulmonary oedema – No D. Polycythaemia – Yes, but this is a chronic change E. Increase in 2,3 DPG – Correct, despite being counterproductive in terms of loading of oxygen in the lungs.… |
|
|
RE12 [d] [Jul98] [Jul01]
Central chemoreceptors: A. Bathed in CSF B. Respond to increase in CSF pH C. Bathed in ECF D. In medullary respiratory centre |
RE12 [dfl] Central chemoreceptors:
A. Bathed in CSF – No, bathed in ECF which communicates freely with the CSF B. Respond to increase in CSF pH – No, a decrease in pH (ie. Increase H+ ions) stimulates it C. Bathed in ECF - Correct D. In medullary respiratory centre – No, while it is indeed in the medulla it is not part of the ‘respiratory centre’ |
|
|
RE13 [d] [Jul98] [Mar99] [Apr01] [Jul01] [Jul02] [Mar03] [Jul03] [Feb04]
The peripheral chemoreceptors: A. Have a nonlinear response to paO2 changes B. Have an intact response at 1MAC C. Respond to a fall in paCO2 D. Respond slowly to rise in paCO2 E. Respond to alkalaemia F. Respond only to ?incr-/decr-eased H+ G. Respond only to arterial hypoxaemia H. Innervated by glossopharyngeal nerve I. Low metabolic rate J. Stimulated by carbon monoxide K. Stimulated by cyanide L. Blood flow of 2 ml/gram/min (OR Blood flow of 200mls/G/min) M. Aortic body innervated by vagus N. Changes in arterial oxygen content O. Low O2 extraction (OR: Low A-V O2 difference P. Have glomus cells |
A. they do have a nonlinear response to paO2 changes- in fact they register changes as high as pO2 500mmHg, but the response really gears up at around 70mmHg, and maximum response is below 50mmHg.
B. their response is eliminated by as little as 0.1 MAC- bad news for CO2 retainers C. they respond to a rise in paCO2 D. they respond around five times more rapidly than the central chemoreceptors to an increase in paCO2 E. they respond to acidaemia (their response is to pO2, pH and pCO2). NB:They also do respond to reduction in their perfusion rate (Nunn 63) F. therefore they do not respond only to H+ G. or only to arterial hypoxaemia H. they are innervated by Hering's nerves -> Glossopharyngeal n -> dorsal respiratory centre of the medulla I. they have a high metabolic rate J. Cyanide and Carbon Monoxide are chemical stimulants (as well as nicoteine and acetylcholine)[addit: Carbon monoxide is NOT a stimulant of the peripheral chemoreceptors (Ganong 19th Ed P.644 and P.659)] K. As above L. blood flow is 20 times their weight per minute- 20mL/g/min or 2,000mL/100g/min M. the aortic bodies are innervated by the vagus -> dorsal medullary respiratory centre N. yes they respond to changes in arterial oxygen content ( I would disagree. see page 109 Kam 2nd edn. "The peripheral chemoreceptors are stimulated by low oxygen tension (PaO2), not low oxygen content (CaO2) of blood. Conditions with low blood oxygen content but relatively normal oxygen tension (anaemia, carboxyhaemoglobin) do not stimulate ventillation via the peripheral chemoreceptors. O. depite their high metabolic rate, the enormous amount of blood flow results in very little oxygen being removed- therefore they have a very low A-V O2 difference, and respond to arterial rather than venous pO2 P. yes they have glomus cells |
|
|
Peripheral chemoreceptors:
A. In the carotid sinus B. Have glomus cells C. Low A-V difference D. Innervated by glossopharyngeal nerve E. Blood flow of 200mls/g/min |
Peripheral chemoreceptors:
A. In the carotid sinus – No, carotid & aortic bodies B. Have glomus cells – The carotid bodies do (two types, type I and II) C. Low A-V difference – Correct (true of the carotid bodies) D. Innervated by glossopharyngeal nerve – Not technically, the carotid sinus is innervated by the carotid sinus nerve – a branch of the glossopharyngeal nerve…but not the aortic body (vagal) E. Blood flow of 200mls/G/min – No, 2000 ml/100g/min = 20 ml/g/min |
|
|
RE13b [Feb04]
Carotid bodies (Similar to RE13) A. Have glomus cells B. Innervated by vagus C. Blood flow of 200mls/g/min D. High A-V difference |
Carotid bodies (Similar to RE13)
A. Have glomus cells - true B. Innervated by vagus - false. the aortic bodies are innervated by the vagus, the carotid bodies by the glossopharyngeal nerve C. Blood flow of 200mls/g/min – false, blood flow is 20 times their weight per minute- 20mL/g/min or 2,000mL/100g/min D. High A-V difference – false, they have a low A-V difference, despite high metabolic rate, because they have a very high blood flow E. Afferents via CN IX |
|
|
RE14 [d] [Jul98] [Jul99] [Jul00]
Surfactant: A. Causes hysteresis (Or: Is the ONLY cause of hysteresis) B. Is produced by type 1 pneumocytes C. Is commonly deficient in term neonates D. Acts like detergent in water E. Reduces the amount of negative intrapleural pressure F. Production is slow G. Increases pulmonary compliance |
RE14 [dfhj] Surfactant:
A. Causes hysteresis (Or: Is the ONLY cause of hysteresis) – No, any elastic substance shows hysteresis B. Is produced by type 1 pneumocytes – No, type 2 pneumocytes C. Is commonly deficient in term neonates – Not usually D. Acts like detergent in water – No, detergent is not ‘surface active’ E. Reduces the amount of negative intrapleural pressure – No effect on intrapleural pressure… F. Production is slow – No, synthesis is fast with a rapid turnover (West p84) G. Increases pulmonary compliance – Yes |
|
|
RE14b [Jul04]
Surfactant A. Surface tension is inversely proportional to surfactant concentration B. Lung compliance decreases with surfactant C. Is produced by alveolar type 1 cells D. Stabilises alveoli to allow smaller alveoli to empty into larger ones E. Increases surface tension in smaller alveoli to promote stability |
Re: RE14b:
A. true, surface tension is decreased with increasing surfactant concentration B. lung compliance increases with surfactant C. produced by type II cells D. stabilises alveoli to prevent them emptying into bigger ones E. decreases surface tension in smaller alveoli to promote stability |
|
|
RE15 [Jul97] [Apr01]
In quiet breathing, exhalation is: A. Passive due to elastic tissue alone B. Passive due to surface tension in the alveoli and elastic tissue recoil C. Active due to intercostal contraction D. ? E. ? |
RE15 [dk] In quiet breathing, exhalation is:
A. Passive due to elastic tissue alone – No, it is due to ‘elastic recoil’ which is more than just elastic tissue B. Passive due to surface tension in the alveoli and elastic tissue recoil - Yes C. Active due to intercostal contraction – No D. ? E. ? |
|
|
RE16 [d] [Mar98] [Jul98] [Apr01] [Mar03] [Jul03]
The normal arterio-venous difference for CO2 is: A. 2 ml/100ml B. 4 ml/100ml C. 6 ml/100ml D. 8 ml/100ml E. 10 ml/100ml |
ANSWER B
|
|
|
RE17 [d] [Jul98] [Mar99] [Jul00] [Apr01] [Jul01] [Mar02] [Jul02] [Jul04]
The lung: A. Removes/inactivates serotonin (5HT) B. Activates bradykinin C. Converts angiotensin II to I D. Inactivates aldosterone E. Takes up noradrenaline |
ANSWER A
A. Removes/inactivates serotonin (5HT) – Yes, it TAKES UP serotonin B. Activates bradykinin – No, it is inactivated (up to 80%) C. Converts angiotensin II to I – No, the other way around (by ACE) – as does the kidney (20%) D. Inactivates aldosterone – No effect on aldosterone E. Takes up noradrenaline – up to 30% REMOVED |
|
|
Which of the following substances is removed (?inactivated) by the lungs?
A. Serotonin B. Noradrenaline C. Angiotensin I D. Bradykinin E. All of the above |
A. Serotonin – It is TAKEN UP by the lung
B. Noradrenaline – up to 30% REMOVED C. Angiotensin I – No, it is ACTIVATED in the lung D. Bradykinin – Bradykinin is INACTIVATED by the lung E. All of the above |
|
|
Which of the following is inactivated in the lung:
A: Angiotensin II B: Angiotensin I C: Bradykinin D: Vasopressin E: Noradrenaline |
ANSWER C
A: Angiotensin II – NO EFFECT B: Angiotensin I – Converted to Angiotensin II by ACE C: Bradykinin – up to 80% INACTIVATED D: Vasopressin – NO EFFECT E: Noradrenaline – up to 30% REMOVED |
|
|
Metabolic functions of the lung include which one of the following?
A. Inactivates ADH B. Converts Angiotensin II to Angiotensin I C. Activates bradykinin D. Inactivate serotonin (5HT) E. Activation of prostaglandins |
A. Inactivates ADH – NO EFFECT
B. Converts Angiotensin II to Angiotensin I – No, other way around C. Activates bradykinin – No, INACTIVATES it D. Inactivate serotonin (5HT) – almost completely REMOVED E. Activation of prostaglandins – No, removes some prostaglandins |
|
|
Which biologically active substances are partially ?degraded by the lung?
A. Surfactant B. Histamine C. Angiotensin D. Noradrenaline E. ?all/?none of the above |
Mar 02: Which biologically active substances are partially ?degraded by the lung?
A. Surfactant B. Histamine C. Angiotensin D. Noradrenaline - Correct E. ?all/?none of the above |
|
|
RE18 [] [Mar98] [Jul98]
Breathing oxygen : A. Causes pain on re-expansion of collapsed alveoli B. Reduces vital capacity C. ? D. ? |
RE18 [ef] Breathing oxygen :
A. Causes pain on re-expansion of collapsed alveoli – No.. – Mechanism? B. Reduces vital capacity – Yes… C. ? D. ? |
|
|
RE19 [] [Mar98] [Jul98] [Feb00] [Mar02] [Jul02]
Contribution to the increase in CO2 carriage as blood passes from artery into vein: Carbamino HCO3 Dissolved A. 5% 90% 5% B. 30% 60% 10% C. ? D. ? |
RE19 [efi] Contribution to the increase in CO2 carriage as blood passes from artery into vein:
Carbamino HCO3 Dissolved A. 5% 90% 5% - This is the proportion of CO2 carriage in ARTERIAL blood B. 30% 60% 10% - this is correct C. ? D. ? |
|
|
RE20 [Mar98] [Mar03]
Increased physiological dead space with: A. Decreases with age B. Anaesthesia C. Supine position D. Calculated from Bohr equation using end-tidal CO2 E. Calculated from endtidal CO2 and arterial CO2 F. Decreases with increase in anatomical dead space G. Increases with PEEP |
RE20 [eo] Increased physiological dead space with:
A. Decreases with age – No, increases B. Anaesthesia – Yes, but variable C. Supine position – No effect D. Calculated from Bohr equation using end-tidal CO2 - No E. Calculated from endtidal CO2 and arterial CO2 - No Factors increasing west zones 1! hypotension, PE, supine, anaesthesia, age, PEEP. |
|
|
RE20b [Jul98] [Feb00]
Physiological dead space increases with: A. Pulmonary hypertension B. Hypotension C. Atelectasis D. Pleural effusion E. None of the above |
RE20b [fi] Physiological dead space increases with:
A. Pulmonary hypertension B. Hypotension – Yes C. Atelectasis D. Pleural effusion E. None of the above |
|
|
RE21 [Mar98] [Mar99] [Feb00]
Shunt can be calculated by knowing: A. Cardiac output B. Arterial oxygen content C. Mixed venous oxygen content D. End pulm. capillary oxygen content E. All of the above |
ANSWER E
|
|
|
RE22 [Jul98]
Alveolar pressure: A. Is always negative throughout normal quiet breathing B. Is zero (atmospheric pr) during pause between inspiration and expiration C. Is greater than 5-6 cm H2O during quiet expiration D. Is less than 5-6 cms H2O during quiet inspiration |
RE22 [f] Alveolar pressure:
A. Is always negative throughout normal quiet breathing – No, impossible – if it were always negative relative to atmospheric you could never exhale… B. Is zero (atmospheric pr) during pause between inspiration and expiration – If there is no flow, then yes C. Is greater than 5-6 cm H2O during quiet expiration – No, not usually D. Is less than 5-6 cms H2O during quiet inspiration – Hmm… well…. It is less that +5-6 cmH2O during quite breathing… I’m assuming the number was NEGATIVE in the real question |
|
|
Alveolar pressure during quiet breathing:
A. 5 cmsH2O negative at inhalation B. 5 cmsH2O positive at expiration C. Follows intrapleural pressure closely D. Is atmospheric between inhalation & exhalation |
ANSWER D
|
|
|
RE23 [Mar99] [Apr01] [Jul03] [Feb04]
Patient with chronic airflow limitation: A. Gradient maximal in effort independent part of flow volume loop B. Will have increased total lung capacity C. Has increased static compliance D. ? |
RE23 [gk] Patient with chronic airflow limitation:
A. Gradient maximal in effort independent part of flow volume loop B. Will have increased total lung capacity – Yes, in order to have the increased elastic recoil of the lungs aid in expiration C. Has increased static compliance – No, compliance is decreased D. ? |
|
|
RE24 [Jul98] [Mar99] [Jul00]
One lung anaesthesia: A. High FIO2 will completely correct paO2 B. CPAP will completely correct paO2 C. Supine position will give better VQ matching D. Associated with hypercarbia E. None of the above |
ANSWER E
A. High FIO2 will completely correct paO2 – No, not completely. There will always be some blood flow through the un-ventilated lung leading to shunt (which can’t be corrected by increasing the FiO2) B. CPAP will completely correct paO2 – No, there is a shunt present C. Supine position will give better VQ matching – False, worse VQ matching if supine D. Associated with hypercarbia –False, if relaxed then it is dependent ventilation which is not usually an issue E. TRUE |
|
|
RE25 [Jul98] [Mar99] [Mar03] [Jul03]
The partial pressure of oxygen in dry air at sea level: A. 163 mmHg B. 159 mmHg C. 149 mmHg D. 100 mmHg E. ? |
RE25 [fg] The partial pressure of oxygen in dry air at sea level:
A. 163 mmHg B. 159 mmHg– Yes, 159.6 (0.21 * 760) C. 149 mmHg D. 100 mmHg |
|
|
RE26 [Mar99] [Jul04]
Cause of increased minute ventilation with exercise: A. Oscillation in paO2 & paCO2 B. Hypercarbia C. Hypoxaemia D. Acidosis E. None of the above |
RE26 [g] Cause of increased minute ventilation with exercise:
A. Oscillation in paO2 & paCO2 – Possibly… although there are MANY factors implicated… B. ? C. ? D. ? |
|
|
RE27 [Jul99] [Feb00] [Apr01]
Work of breathing (as % of total VO2) in normal healthy adult:: A. 1% B. 5% C. 10% D. 20% |
RE27 [hik] Work of breathing (as % of total VO2) in normal healthy adult::
A. 1% - Correct (10% of this goes into actually moving air) but the books say ‘<5%’ so (B) could be a better option…. B. 5% C. 10% D. 20% |
|
|
RE28 [Feb00] [Mar03] [Jul03] PEEP:
A. Has a variable effect on FRC B. Reduced lung compliance C. Reduces lung water D. Reduces airway resistance E. No effect on lung compliance |
RE28 [i] PEEP causes:
A. Variable effect on FRC – Possibly not B. Reduced lung compliance – No, if anything it would increase it C. Decrease in lung water – No D. Reduces airway resistance – Correct (Nunn p608) |
|
|
RE29 [Feb00] [Jul02]
At an atmospheric pressure of 247 mmHg, what is the moist inspired p02? A. 200 mmHg B. 2 mmHg C. 40 mmHg D. 50 mmHg |
ANSWER C
A. 200 mmHg B. 2 mmHg C. 40 mmHg – (0.21 * 200) = 42mmHg D. 50 mmHg |
|
|
RE30 [Feb00]
Type II pneumocytes A. Develop from type I pneumocytes B. Are macrophages C. Are very flat and practically devoid of organelles D. ?Metabolise surfactant |
RE30 [i] Type II pneumocytes
A. Develop from type I pneumocytes – No, the other way around B. Are macrophages – No, alveolar macrophages are macrophages ☺ C. Are very flat and practically devoid of organelles - No D. ?Metabolise surfactant – Well… they produce it and recycle it so this is correct |
|
|
RE30b [Jul00]
Type I pneumocytes A: Give rise to Type II pneumocytes B: Are flat & minimal organelles C: Bind surfactant (? receptors) on their brush border D. ? |
RE30b [j] Type I pneumocytes
A: Give rise to Type II pneumocytes – No, converse is true B: Are flat & minimal organelles - Yes C: Bind surfactant (? receptors) on their brush border – No, surfactant doesn’t bind to anything D. ? |
|
|
RE31 [Jul00]
Control (?inspiratory) of the diaphragm originates in: A. Pneumotactic centre B. Apneustic centre in pons C. Dorsal medullary (?neurons of) respiratory centre D. Ventral medullary (?neurons of) respiratory centre |
RE31 [j] Control (?inspiratory) of the diaphragm originates in:
A. Pneumotactic centre B. Apneustic centre in pons C. Dorsal medullary (?neurons of) respiratory centre – This does control inspiration – most correct D. Ventral medullary (?neurons of) respiratory centre |
|
|
RE32]] [Jul00]
For a normal Hb-O2 dissociation curve, the most correct relationship is: A. PaO2 340mmHg, SaO2 99% B. PaO2 132mmHg, SaO2 98% C. PaO2 68mmHg SaO2 70% D. PaO2 60mmHg, SaO2 91% E. None of the above |
ANSWER D
The ICU point |
|
|
RE34 [Jul00]
Oxygen toxicity: A: Is caused by superoxide dismutase (OR: Increased by increased SOD) B: Causes CNS toxicity at over 100kPa C: Is caused by absorption atelectasis D: Is due to formation of superoxide radicals E: Prolonged ventilation at 50kPa causes pulmonary toxicity F. Causes lipid peroxidation |
RE34 [j] Oxygen toxicity:
A: Is caused by superoxide dismutase (OR: Increased by increased SOD) B: Causes CNS toxicity at over 100kPa C: Is caused by absorption atelectasis – No D: Is due to formation of superoxide radicals – Yes… E: Prolonged ventilation at 50kPa causes pulmonary toxicity F. Causes lipid peroxidation – Yes, as well. But (D) probably the better answer |
|
|
RE35 [Jul00] [Apr01]
Pulmonary stretch receptors: A. ? B: Are only stimulated by maintained stretch C: Show (?slow) adaptation D: Cause an immediate decrease in tidal volume E. ? |
RE35 [jk] Pulmonary stretch receptors:
A. ? B: Are only stimulated by maintained stretch - No C: Show (?slow) adaptation - Correct D: Cause an immediate decrease in tidal volume - No E. ? |
|
|
RE36 [Jul00]
The peripheral chemoreceptors are located: A. Carotid sinus B. Carotid bodies C. The vasomotor centre D. ? |
ANSWER B
A. Carotid sinus – No, this is a baroreceptor B. Carotid bodies – Correct (and in the aortic bodies) C. The vasomotor centre – No D. ? |
|
|
RE37 [Apr01] [Mar03] [Jul03]
Mixed venous blood: A. Higher haematocrit than arterial B. Saturation of 48% C. Higher pH than arterial Blood D. Can be sampled from the right atrium E. pO2 lower than coronary sinus blood F. Coronary sinus O2 saturation of 30% |
ANSWER A
A. Higher haematocrit than arterial – Yes, this is due to the increased osmoles in the red cells B. SaO2 48% - No pO2 is 40mmHg, with SpO2 75% C. Higher pH than arterial Blood – No, pH may be a little lower or normal D. Best sampling site RA – No, probably the pulmonary artery E. pO2 lower than coronary sinus blood – No, pO2 of Coronary sinus blood is 20mmHg F. Coronary sinus O2 saturation of 30% - No, 60% extraction (sats approx 40%) with pO2 of 20mmHg |
|
|
RE38 [Apr01]
Carbon dioxide carriage: a) 10% dissolved b) 30% carbamino c) 85% bicarbonate d) 60% bicarbonate e) Unaffected by pO2 |
RE38 [k] Carbon dioxide carriage:
a) 10% dissolved – 5% b) 30% carbamino - 5% c) 85% bicarbonate – 90% bicarbonate in arterial system but correct for VENOUS d) 60% bicarbonate – 60% of the A-V difference e) Unaffected by pO2 – No, this will affect Hb saturations and hence influence the Haldane effect |
|
|
RE39 [Apr01]
Factors that favour formation of carbamino-haemoglobin include: A. Carbonic anhydrase B. A decrease in oxygen tension C. An increase in oxygen tension D. A decrease in pH E. None of the above |
RE39 [k] Factors that favour formation of carbamino-haemoglobin include:
A. Carbonic anhydrase – No effect on carbamino compounds – this will affect the amount of H+ that needs to be buffered (the minor part of the Haldane effect) B. A decrease in oxygen tension – It is the OxyHb % that is important, not the tension per se C. An increase in oxygen tension – No D. A decrease in pH – No effect E. None of the above – Correct answer |
|
|
RE40 [Apr01]
CO2 diffusion limited because A. Combines avidly with Hb B. Partial pressure in blood increases as partial pressure in air increases C. ? |
RE40 [k] CO2 diffusion limited because – is this meant to read CO (ie carbon monoxide)?
A. Combines avidly with Hb – Correct, if referring to CO (this is the reason why the pp does not rise much) B. Partial pressure in blood increases as partial pressure in air increases – if CO, then this is incorrect C. ? |
|
|
RE41 [Jul01] [Jul05]
Oxygen toxicity may be seen: A. In CNS and lungs if breath 100% at 1 ATA (?) for 24 hours B. In CNS and lungs if breath 30% at 1 ATA (?) for 24 hours C. In CNS if breathe 100% oxygen for 48 hours D. ? E. CNS toxicity seen with O2 concs far greater than 760mmHg |
RE41 [l] Oxygen toxicity may be seen:
A. In CNS and lungs if breath 100% at 1 ATA (?) for 24 hours B. In CNS and lungs if breath 30% at 1 ATA (?) for 24 hours C. In CNS if breathe 100% oxygen for 48 hours D. ? E. CNS toxicity seen with O2 concs far greater than 760mmHg – Correct. 3 Atm at 100% Oxygen (Nunn) |
|
|
RE42 [Jul01]
Breathing 0.04% CO2 in one atmosphere for 30 minutes, you would see: A. Periodic apnoeas (or: ‘periods of apnoea’) B. Hyperpnoea C. Signs of acidosis D. Signs of alkalosis E. No change |
RE42 [l] Breathing 0.04% CO2 in one atmosphere for 30 minutes, you would see:
A. Periodic apnoeas (or: ‘periods of apnoea’) B. Hyperpnoea C. Signs of acidosis D. Signs of alkalosis E. No change – This is normal atmospheric CO2 content according to NASA |
|
|
RE43 [Jul01] [Feb04]
In the lung, airway resistance A Mainly in small airways B Varies with change in lung volume C Increased by stimulation of adrenergic receptors D Can be measured by flow rate divided by pressure difference between mouth and alveolus E Increased by breathing helium-oxygen mixture |
RE43 [l] In the lung, airway resistance
A Mainly in small airways – No, mainly in segmental bronchi (generations 1-4) B Varies with change in lung volume – Yes C Increased by stimulation of adrenergic receptors – No, decreased (ie bronchodilation) D Can be measured by flow rate divided by pressure difference between mouth and alveolus E Increased by breathing helium-oxygen mixture – No, decreases |
|
|
RE44 [Jul01]
The effect of decreasing airway diameter has the following effect on airway resistance: A. 1/8 B. ¼ C. ½ D. 4 times E. 16 times |
RE44 [l] The effect of decreasing airway diameter has the following effect on airway resistance:
A. 1/8 B. ¼ C. ½ D. 4 times E. 16 times – increases 16x (for laminar flow) – if you HALVE the diameter |
|
|
RE45 [mno] Gas composition of air?
PO2 PCO2 PN2 P other gases A. 20.98 O.4 ? B. 20.98 0.4 ? C. 21 0.04 ? D. 20.98 0.04 78.58 0.42 E. 20.98 0.04 78.2 0.98 |
RE45 [mno] Gas composition of air?
PO2 PCO2 PN2 P other gases A. 20.98 O.4 ? B. 20.98 0.4 ? C. 21 0.04 ? D. 20.98 0.04 78.58 0.42 E. 20.98 0.04 78.2 0.98 – Most correct, except it adds up to more than 100%!! |
|
|
RE46 [mn]. What happens to lung function in COAD
A. Decreased static compliance – No, increased (but decreased dynamic compliance) B. Increased TLC – Yes, grossly increased C. Decreased airway resistance – No, grossly increased D. Increased FEV1 – No, often decreased E. ?? |
RE46 [mn]. What happens to lung function in COAD
A. Decreased static compliance – No, increased (but decreased dynamic compliance) B. Increased TLC – Yes, grossly increased C. Decreased airway resistance – No, grossly increased D. Increased FEV1 – No, often decreased |
|
|
RE47 [Mar03] [Jul03] [Feb04] [Jul04] [Mar05]
The amount of oxygen dissolved in plasma is A. 0.03ml O2/100ml at PaO2 100mmHg B. 6ml O2/100ml breathing 100% O2 at 3 atmospheres C. 6ml O2/100ml breathing room air at 3 atmospheres D. 0.3ml O2/l breathing room air at 1 atmosphere E. 6 mlO2/100mls breathing 100% O2 |
ANSWER B
A. 0.03ml O2/100ml at PaO2 100mmhg – No, 0.3 (same units) B. 6ml O2/100ml breathing 100% O2 at 3 atmospheres - Correct C. 6ml O2/100ml breathing room air at 3 atmospheres D. 0.3ml O2/l breathing room air at 1 atmosphere – No, 3 (same units) E. 6 mlO2/100mls breathing 100% O2 ie. NOT Hb bound… |
|
|
RE48 [] [Mar03] [Jul03] [Jul04]
Closing capacity (in young adults) A. Increases with anaesthesia B. 10% vital capacity C. Decreases with age D. Responsible for relative hypoxaemia in healthy adult patients under anaesthesia E. The same as FRC in elderly supine patients |
ANSWER D
A. False - Decreases in parallel with FRC (Accord. to Nunn's 6th Ed p304) B. False - closing volume is about 10% of vital capacity in young normal subjects (West 7th ed p. 163) C. False - increases with age. CC=FRC at mean age 44 supine, CC=FRC at mean age 66 erect D. I'd say false, it is more the reduction in FRC and its reaching CC under anaesthesia that causes the atelectsis, not the CC itself. Although this may be the only right answer ??? E. False - unless 44 is considered "elderly" |
|
|
RE49 [Mar03] [Jul03] [Feb04]
Measurement of Functional residual Capacity (FRC): A. Helium dilution does not measure unventilated spaces on chest B. Body plethysomography inaccurate if high FIO2 used C. Helium used to decrease airflow viscosity D. Body plethysomography requires oesophageal probe E. ? |
RE49 [Mar03] [Jul03] [Feb04]
Measurement of Functional residual Capacity (FRC): A. Helium dilution does not measure unventilated spaces on chest B. Body plethysomography inaccurate if high FIO2 used C. Helium used to decrease airflow viscosity D. Body plethysomography requires oesophageal probe E. ? A is true B - can't think of a reason for this to be true C Helium is used because very little is lost into blood as poorly soluble. D is false |
|
|
RE50 [Mar03] [Jul03] [Feb04]
The absolute humidity of air saturated at 37C: A. 760 mmHg B. 47 mmHg C. 100% D. 44mg/m3 E. 17mg/m3 |
RE50 [o] The absolute humidity of air saturated at 37C:
A. 760 mmHg B. 47 mmHg C. 100% D. 44mg/m3 E. 17mg/m3 NONE of these is correct!! The correct answer is 44g/m3 OR 44mg/L I hope it is not like this on the exam… if it is… go with (D) |
|
|
RE51 [Jul03] [Feb04] [Jul04]
Surface Tension A. Is inversely proportional to the concentration of surfactant molecules per unit area B. Cause the small alveoli to collapse into the larger ones C. ? D. ? |
RE51 [Jul03] [Feb04] [Jul04]
Surface Tension A. Is inversely proportional to the concentration of surfactant molecules per unit area B. Cause the small alveoli to collapse into the larger ones C. ? D. ? SURFACTANT stabilises small alveoli to prevent them empty into the larger ones. SURFACE TENSION causes small alveoli to collapse into the larger ones. i still think both A and B are true, since the question is about surface tension rather than surfactant. |
|
|
RE52 [Jul03]
Atalectasis causes hypoxaemia because of: A. ? B. ? C. ? D. ? E. Increased shunt |
RE52 [Jul03]
Atalectasis causes hypoxaemia because of: A. ? B. ? C. ? D. ? E. Increased shunt |
|
|
Which of the following is closest value for mixed venous PO2 breathing 100% oxygen?
A. 50 mmHg B. 75 mmHg C. 100 mmHg D. 600 mmHg E. 660 mmHg |
ANSWER A
For FiO2 of 21%: PAO2 = 149 - 40/.08 + 2 = 101mmHg [let us assume A-a gradient of 4mmHg] PaO2 = 97mmHg [let us assume SpO2 = 98%; and Hb = 120g/L, or 12g/dL] CaO2 = 1.39 x 12 x .98 + 0.003 x 97 = 16.28 ml/100ml [let us assume 4.8ml/100ml extraction] CvO2 = 16.28 - 4.8 = 11.48 ml/100ml Now, this part is a bit dodgy mathematically, but: Because CvO2 = 1.39 x 12 x SvO2 + 0.003 x PvO2, for ease of math I'm going to assume 0.003 x PvO2 is insignificant; Therefore SvO2 = 11.48/(1.39x120) = 68.8% And if we refer to the O2 dissociation curve... PvO2 =~ 35mmHg For FiO2 = 100% PAO2 = 713 - 40/.08 + 2 = 663mmHg PaO2 = 659mmHg [let us assume SpO2 = 100% with the higher FiO2, just for the benefit of my consultant]' CaO2 = 1.39 x 12 x 1 + 0.003 x 663 = 18.67 ml/100ml [let us assume 4.8ml/100ml extraction] CvO2 = 18.67 - 4.8 = 13.87 ml/100ml Therefore SvO2 = 13.87/(1.39x120) = 83.2% And if we refer to the O2 dissociation curve... PvO2 =~ 48mmHg |
|
|
RE54 [Feb04] [Jul04]
Which of the following is the best explanation for the different effects on PaO2 and PaCO2 of VQ mismatch? A. Different solubilities of O2 and CO2 B. Different dissociation curves C. Effect of compensatory hyperventilation |
RE54 [Feb04] [Jul04]
Which of the following is the best explanation for the different effects on PaO2 and PaCO2 of VQ mismatch? A. Different solubilities of O2 and CO2 B. Different dissociation curves C. Effect of compensatory hyperventilation B is true. WHY????? PaO2 is decreased in VQ mismatch - why? Say there are 3 alvoeli - Alveolus A has low V/Q, B has normal V/Q, C has high V/Q. The total O2 content would be the addition of O2 content in the end capillaries of A, B and C. Alveolus A has low V/Q, low pO2, high pCO2. The low pO2 lies on steeper part of the ODC, therefore O2 content in end capillary A is significantly decreased (eg 16mL/dL as in the example in West) Alveolus B has normal V/Q, O2 content is normal (19.5mL/dL) Alveolus C has high V/Q, high pO2, low pCO2. The high pO2 means that it lies on the flattened part of the ODC, therefore O2 content in end capillary C is not significantly greater than that of normal (20mL/dL in West) So when we add all 3 end capillary blood together to give us the final pulmonary venous blood, the low O2 content from the low V/Q alveoli depresses the total O2 content much greater than the high V/Q alveoli would increase total O2. Therefore the effect of V/Q mismatch on PaO2 is because of the shape of the dissociation curve. For CO2, the dissociation curve is almost linear in the physiological range, so the high V/Q and low V/Q should balance each other out and PaCO2 should not be affected. Note: If there is severe hypoxaemia from V/Q mismatch eg in a large shunt, hyperventilation may occur due to peripheral chemoreceptors. In this situation the pCO2 will then by affected. However, in this question the best answer is still B. _____________________________________________________________________________ The dissociation curve for CO2 is linear in the physiological range however the contribution from areas of low VQ ratios is going to be more because of the higher blood flow in these units. I agree that for O2 the shape of the HbO2 dissociation curve produces the greatest effect, but in terms of CO2 I would argue that hyperventilation is more important. Can anyone comment on this? The point is that the reason for the differing effects of hyperventilation on PaCO2 and PaO2 is the difference in their respective disocciation curves. The way I understood what West said was that you are able to excessively ventilate the high VQ ratio units to remove the CO2 reducing content here (not altering O2 content) by an amount that compensates for the low VQ ratio units (which are not really able to be ventilated much more than they are already. The linear disscoiation curve of CO2 means you can do this. Hyperventilation itself doesn't to me seem like a good answer as it is not the reason for the lower O2 is not able to be improved. Does that help at all? nr The other clue in the question could be the use of "hyperventilation". I would argue that if the ventilation needs to be increased to eliminate CO2 - to keep paCO2 in the normal range - then this is merely "adequate" ventilation, not hyperventilation. [edit] References & related material West - Respiratory Physiology (7th ed) pg 67-68) |
|
|
RE55 [Feb04]
Functional Residual Capacity A. Decreases with age B. Decreases with obesity |
RE55 [Feb04]
Functional Residual Capacity A. Decreases with age B. Decreases with obesity FRC is about 30ml/kg in adults and children. It is almost fully established in the neonate at 60mins after birth. Increased with: increased height changing from supine to erect (30% higher) less elastic recoil (ie, emphysema) Decreased with obesity pregnancy supine positioning anaesthesia (with or without paralysis) pulmonary disease causing increased elastic recoil (pulmonary fibrosis) It does not really change with age - however, the relationship between closing capacity and FRC does |
|
|
RE56 [Jul04]
Correction of hypoxaemia in anaesthetised patient: A. Increase airway pressures between breaths B. V/Q matching C. Decrease dead space |
RE56 [Jul04]
Correction of hypoxaemia in anaesthetised patient: A. Increase airway pressures between breaths B. V/Q matching C. Decrease dead space I think A? If hypoxaemia is related to atelectasis then, yes, increasing airway pressures between ventilation (PEEP) would correct this. (Brings FRC up). Isn't this then V/Q matching also? It is but the initiating problem is atelectasis treatable with PEEP. Hypoxaemia during anaesthesia occurs due to decreased FRC, below closing capacity, and atelectasis with consequent shunting. Hypoxic pulmonary vasoconstriction is impaired by volatile agents and shunting is more of a problem than in the awake patient with similar degree of atelectasis. Unfortunately there are not good interventions to improve HPV but PEEP (or recruitment manoeuvres) will reduce the atelectasis which is the original cause of the problem. For this reason I would choose A. Addition: On the other hand... PEEP can create more West zone 1 thus increase alveolar dead space so i thinks it B or C Add: But a shunt eg atelectasis is more likely to cause hypoxaemia than a small increase in dead space? I would go for A, would always reach for the peep knob instead of the adrenaline or fluid in a mild dropping sats in OT.. |
|
|
RE57 [Jul04]
Lung compliance A. Measurement requires a respiratory laboratory B. dynamic greater than static C. Static and dynamic same in emphysema D. Difference between static and dynamic due to airflow resistance E. Due to surface tension |
ANSWER D
Difference between static and dynamic due to airflow resistance Static Compliance Measured after lung volume has been held at a fixed volume for as long as is practicable (in conscious subjects, obviously much easier in paralyzed victims). This means sufficient time should be given for functional respiratory units to equilibrate and contribute equally in the calculation of compliance. Dynamic Compliance Sacrifices this luxury for the sake of simplicity in measurement, whereby compliance is (hastily) assessed at points of no-flow (at the mouth -- not within the lung) at end-inspiration and end-expiration. Therefore not allowing complete equilibration in the case of diseased lung where airway resistance in differing functional units will yield different time constants. |
|
|
RE58 [Mar05] Barometric pressure is half that of sea level at:
A. 550m B. 1500m C. 5500m D. 7000m E. 19500m |
RE58 [Mar05] Barometric pressure is half that of sea level at:
A. 550m B. 1500m C. 5500m D. 7000m E. 19500m At 18,000ft, or 5486m, pressure is half that of sea level |
|
|
RE59 [Mar05] [Jul05]
Regarding O2 carriage in blood (or regarding red blood cells): A. B. C. HbS less soluble than HbA D. E. MetHb has 85% the O2 carrying capacity of normal Hb |
RE59 [Mar05] [Jul05]
Regarding O2 carriage in blood (or regarding red blood cells): A. B. C. HbS less soluble than HbA D. E. MetHb has 85% the O2 carrying capacity of normal Hb C- correct, HbS where valine replaces glutamic acid on beta-chain causes critical loss of solubility if reduced Hb leading to polymerisation and "sickle" shape of Hb at PaO2 less than 40mmHg. (Nunn resp phys) |
|
|
RE61 [Jul05]
Static Compliance A. B. Depends on airway resistance C. Depends on surfactant levels D. E. Due to surface tension |
RE61 [Jul05]
Static Compliance A. B. Depends on airway resistance C. Depends on surfactant levels D. E. Due to surface tension C is true Is typically 200ml/cmH2O (1mmHg=1.36cmH2O).Is measured in vivo with a conscious,relaxed,upright subject,at different degrees of deflation from near TLC when no air is flowing. Factors affecting static compliance: lung vol (normally measured at FRC. If only 1 lung dV is half that for a given dP) FRC variation due to body size (specific compliance 0.05cmH2O relates changes in dV & dP to FRC (dV/dP)/FRC ) pulmonary blood vol (comp v with congestion) alveolar collapse lung disease |
|
|
RE62 [Jul05] Gas solubilities with decreased temperature (Also remembered as “Under a general anaesthetic, if a patient becomes hypothermic, you can expect to see:)
A. Increased PACO2, Decreased PAO2 B. Increased PACO2, Increased PAO2 C. No change in PACO2 or PAO2 (OR: PAO2 no change, decreased PACO2) D. Decreased PACO2, Increased PAO2 E. Decreased PACO2, Decreased PAO2 |
RE62 [Jul05] Gas solubilities with decreased temperature (Also remembered as “Under a general anaesthetic, if a patient becomes hypothermic, you can expect to see:)
A. Increased PACO2, Decreased PAO2 B. Increased PACO2, Increased PAO2 C. No change in PACO2 or PAO2 (OR: PAO2 no change, decreased PACO2) D. Decreased PACO2, Increased PAO2 E. Decreased PACO2, Decreased PAO2 http://www.anaesthesiamcq.com/wiki/mcqwiki/index.php/RE62 =>wow, they went nuts! Pretty simple rule: if you boil water, bubbles appear, e.g. solubility of CO2 and O2 decreases with hyperthermia and increases with hypothermia, but since only a very small part of O2 is dissolved but more 5%(Art) -> 10%(ven) for CO2, this means CO2 most affected and answer is: more dissolved CO2 with hypothermia compared to O2. Thus: C (OR: PAO2 no change, decreased PACO2) |
|
|
RE63 [Feb06] Anatomical dead space
A. measured by carbon monoxide inhalation B. 2ml/kg in average adult. C. increases when supine D. decreased with intubation E. contains end tidal CO2 |
ANSWER B
Anatomical dead space is the volume of the conducting airways which is around 150ml or 2.2ml/kg for the average adult. It is influenced by size (17mls for every 10cm) age posture (sitting 157ml supine 101ml) the position of the head and neck,lung volume and intubation (increases apperatus dead space decreases anatomic). Fowler's method is used to calculate anatomic dead space.(single insp of 100% O2 followed by measurement of expired N2. Increasing conc of expired N2 is plotted against expired volume). The Bohr equation (nmemonic 'DAETA')is used to calculate physiologic dead space. Anatomic dead space is mostly atmospheric air with a little CO2 |
|
|
RE64 [Feb06]
With regard to dead space: A. Bohr equation can be used for anatomical dead space B. Nitrogen washout can be used for alveolar dead space C. Physiological dead space calculated from end-tidal CO2 D. Physiological dead space can be calculated from end-tidal CO2 and alveolar CO2 |
RE64 [Feb06]
With regard to dead space: A. Bohr equation can be used for anatomical dead space B. Nitrogen washout can be used for alveolar dead space C. Physiological dead space calculated from end-tidal CO2 D. Physiological dead space can be calculated from end-tidal CO2 and alveolar CO2 By utilising and modifying Bohr equation, anatomical dead space can be calculated-by replacing alveolar with end-expiratory gas in the Bohr equation. Hence, Bohr equation can theoretically be used to calculate anatomical dead space. Ref: Nunn 6th ed., p121. |
|
|
RE65 [Feb06] Regarding the work of lungs in breathing:
A. ? B. Most work is to overcome airway resistance C. Increased by increasing respiratory rate (i think) D. ? E. Work done is determined by integral of pressure volume loop |
RE65 [Feb06] Regarding the work of lungs in breathing:
A. ? B. Most work is to overcome airway resistance C. Increased by increasing respiratory rate (i think) D. ? E. Work done is determined by integral of pressure volume loop On a plot of respiratory rate vs work of breathing, as respiratory rate increases work to overcome elastic forces decreases and work to overcome airway resistance increases. The total work is minimal when both elastic work and airway resistance work contribute 50%. The total work vs respiratory rate curve is U-shaped and is minimal at rest respiratory rates. However this minimum work point occurs at higher rates in pathologies that increase elastic work (such as pulmonary fibrosis) and at lower rates in pathologies that increase airway resistance work (such as COPD). work due to airway resistance depends on the respiratory rate. change in work due to increasing respiratory rate depends on what the respiratory rate was initially. E is definately true and is the best answer Components that make up the work of breathing during quiet inspiration: Nonelastic work (Viscous resistance (7%)Airway resistance (28%)) Elastic work (65%) The higher the breathing rate the faster the flow velocity (which by using Reynold's number - is more likely to cause turbulent flow, and require increasing pressure changes for the same volume) and the larger the work done in overcoming non elastic work. The work done in overcoming the elastic forces is decreased as respiratory rate increases. Therefore, people with highly compliant lungs and high airways resistance - breath at higher volumes and mroe slowly (ie, emphysema) people with less compliant lungs breath at faster rates, and more shallow volumes (ie, pulmonary fibrosis) |
|
|
RE66 {Feb-06] A-a gradient is increased with:
A. atelectasis B. venous admixture C. Hypoventilation D. reduced cardiac output E. increased diffusion distance for oxygen |
ANSWER A
|
|
|
PH01 [1986]
At an altitude of 14,000 feet (4,200m), ambient pressure is 450mmHg. Breathing air, a normal man has an alveolar pO2 of: A. 40 mmHg B. 50 mmHg C. 55 mmHg D. 60 mmHg E. 80 mmHg |
BEST ANSWER A
PiO2 = FiO2 × (Pb - 47) PiO2 = 0.21 × (450-47) = 84 PAO2 = PiO2 - (PaCO2 / R) PAO2 = 84 - (35 / 0.8) = 40mmHg |
|
|
PH02
Peripheral cyanosis appears when: A. Hb exceeds 17C% B. MetHb level exceeds 0.1G% C. SulpHb level exceeds 0.1G% D. MetHb level exceeds 1.5G% |
ANSWER D
MetHb and SulfHb produce detectable cyanosis at concentration as low as 1.5 gm and 0.5 gm/dl respectively |
|
|
PH03 [1988] [Aug93] [Mar94]
If breathe 100% oxygen, marked increase in paO2 occurs in: A. Hypoventilation B. V/Q abnormality C. Moderate diffusion problems D. True shunt |
ANSWER ABC
Only shunt is not amenable to increasing FiO2 |
|
|
PH16 [1988] [Mar91] [Aug91]
P50 is increased by a fall of: A. 2,3 DPG B. ATP C. Temperature D. pH |
ANSWER D
|
|
|
A child inhales a marble into the left main bronchus. At that instant, compliance is:
A. Halved B. Unchanged C. Doubled D. No constant relation |
ANSWER A
|
|
|
PH26 [Apr96]
The oxygen dissociation curve is moved to the left by: A. Acidosis B. Hypothermia C. Increase in 2,3 DPG D. Blood storage prior to transfusion E. Sickle cell anaemia |
ANSWER B and D
|
|
|
PH27
An increase in 2,3 DPG: A. Shifts ODC to same side as does metabolic acidosis B. Shifts curve in same direction as hypothermia C. Increases storage life of red blood cells D. Decreases oxygen consumption in vivo |
ANSWER A
|
|
|
PH34 [Mar93] [Mar00] (type K)
Hyperventilation to two times normal (?alveolar ventilation) causes: 1. Vasoconstriction in skin 2. Increased arterial pH 3. Decreased cardiac output 4. Decrease in free Ca++ 5. Increased SVR 6. Decreased coronary perfusion |
1, 2, 4, 5 true
hyperventilation : alveolar (therefore arterial) CO2 is inversely related to alveolar ventilation. Double the alv vent will halve the alv and art CO2. - West resp physiol effects - decreased HCO3, increased pH (resp alkalosis), decreased cerebral blood flow leading to symptoms of lightheadedness, dizziness, paraesthesia, increased cardiac output direct vasoconstriction, but depressed vasomotor centre means BP unchanged or only slightly elevated, alkalosis leads to normal total Ca, but fall in free Ca causing tetany/carpopedal spasm. - Ganong |
|
|
Can04-15 You are providing apneic oxygenation to a patient with a tracheal catheter and O2 flow of 2 Lpm. The initial PaCO2 is 30. After 10 minutes, what will the PaCO2 be?
A. 30 mmHg B. 45 mmHg C. 60 mmHg D. 90 mmHg E. 120 mmHg |
ANSWER C or D
Following airway occlusion Alveolar and mixed venous PCO2 quickly equibrate (10seconds) following apnoa Following this with re-circulation both alveolar and mixed venous PCO2 increase 3-6mmHg per minute. 3x10=30mmHg +30mmHg where it started = 60mmHg 6x10=60mmHg +30mmHg= 90mmHg daym |
|
|
Can04-20 What patient does the following ABG represent pH 7.35, PCO2 35 pO2 75, O2Sat 98%
A. neonate B. pregnant C. altitude D. adult |
ANSWER A
|
|
|
Can04-50 In upper abdominal surgery, how long does it take for FRC and VC to normalize?
A. 8-12 hrs B. 13-25 hrs C. 26-36 hrs D. 3-7 days E. 10-14 days |
ANSWER A??
|
|
|
Can04-53 Regarding the oxygen dissociation curve, for a particular PaO2, what will increase the SaO2?
A. decrease in pH B. increase in temperature C. increase in PaCO2 D. decrease in 2,3 DPG E. HbF change to adult hemoglobin |
ANSWER D
|
|
|
A morbidly obese, non-smoking patient who is otherwise well is likely to have a significant reduction in:
1. Functional Residual Capacity (FRC). 2. Forced Expiratory Volume in 1 second (FEV1). 3. Expiratory Reserve Volume (ERV). 4. Diffusing Capacity for Carbon Monoxide (DLCO). A: 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER A
|
|
|
An acclimatised mountaineer, breathing air on the summit of Mount Everest (barometric pressure 253 Torr), will have an arterial PCO2 (PaCO2) of approximately:
A. 24 mm Hg. B. 20 mm Hg. C. 16 mm Hg. D. 12 mm Hg. E. 8 mm Hg. |
ANSWER E
|
|
|
In the left lateral position, blood flow to the non-dependant lung is:
A. 25%. B. 35%. C. 45%. D. 55%. E. 65%. |
ANSWER C
|
|
|
What is the rate of rise of PaCO2 during breath holding?
A. 1 mmHg/min. B. 3 mmHg/min. C. 5 mmHg/min. D. 7 mmHg/min. E. 10 mmHg/min. |
ANSWER B
3-5mmHg PCO2 rise per minute |
|
|
Which of the following are true with respect to increasing oxygen reserves through preoxygenation with 100% oxygen:
1. It is well reflected by the arterial oxygenation saturation. 2. It requires longer when using a Bain circuit. 3. It is achieved equally as well with 4 vital capacity breaths or 3 minutes of tidal volume breathing. 4. Oxygen reserves are reduced in pregnancy. A: 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER D
The Bain Circuit is a co-axial modification of the basic T-piece system, developed to facilitate scavenging of waste anesthetic gases. Delivers 100% fresh gas, therefore will take the same time. |
|
|
Pulmonary Surfactant:
1. Is produced by type II alveolar cells. 2. Is turned over so rapidly that a reduction in pulmonary blood flow can cause a decrease in surfactant production. 3. Synthesis is stimulated by thyroxine and glucocorticoids. 4. Is partly recycled by endocytosis into the synthesising cell. A: 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER E
|
|
|
Acidosis may result in:
1. Potassium retention 2. A rise in plasma chloride 3. A low pCO2 4. Tetany A: 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER A
|
|
|
The gas transfer (DLCO) depends on:
1. The volume of the pulmonary capillary bed. 2. Ventilation perfusion matching 3. Haemoglobin concentration 4. Residual volume A: 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER A
|
|
|
The features of chronic mountain sickness include:
1. A decreased ventilatory response to carbon dioxide. 2. Extreme polycythaemia. 3. A decreased ventilatory response to hypoxia. 4. Thromboembolism A: 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER E
|
|
|
A fit twenty year old male has been thoroughly preoxygenated, rendered apnoeic with thiopentone and suxamethonium and now has oxygen being insufflated into the upper airway at 500 mls/min.
Given this scenario, which of the following statements are true? 1. The PCO2 will rise more in the first minute of apnoea than in the second. 2. Oxygen will be drawn into the apnoeic lung at a rate equal to the difference between O2 utilisation and CO2 production. 3. The arterial PCO2 will exceed the venous PCO2 by about 2 mm Hg after three minutes of apnoea. 4. Apnoea can be safely sustained for no longer than ten minutes. A: 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER B
|
|
|
With regard to lung volumes and capacities:
A. Vital capacity represents the total lung volume. B. Inspiratory capacity is the sum of the tidal volume and the inspiratory reserve volume. C. FEV1 is typically about 90% of the vital capacity. D. Residual volume can be measured by the spirometry. E. Vital capacity is the sum of the inspiratory and the expiratory reserve volumes. |
ANSWER B
|
|
|
Functional residual capacity:
1. Can be measured by the Helium dilution technique. 2. Decreases with age. 3. Decreases following prolonged exposure to 100% oxygen. 4. Exceeds closing capacity in a fit 20 year old in the supine position. A 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER B
|
|
|
The partial pressure of oxygen in the 'ideal' alveolar gas during air breathing:
1. Varies with atmospheric pressure. 2. Varies with ambient humidity. 3. Will transiently rise during induction of anaesthesia with a mixture of 21% oxygen in nitrous oxide. 4. Is greater than in the mixed expired air. A 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER B
|
|
|
Signs and symptoms associated with carbon monoxide (CO) poisoning include:
1. Irritability. 2. Metabolic acidosis. 3. Coma. 4. Cyanosis. A 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER A
|
|
|
Which of the following methods can be used to measure functional residual capacity (FRC)?
1. Helium dilution. 2. Bohr's method. 3. Body plethysmograph. 4. Fowler's method. A 1,2,3 Correct B: 1,3 Correct C: 2,4 Correct D: 4 Correct E: All Correct |
ANSWER B
|
