Biomedical Engineering - BIOENGINEERING OF THE RESPIRATORY SYSTEM

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Bio engineering of the R espiratory System 27 Feb 201 7 FAMILY NAME ………………………… N AME ……………………………. MATR ………… ORAL : 2 Mar (h. 10 .00-12.30 )  2 Mar (h. 14.30 -17.30)  3 Mar (h. 10.00 -12.30)  3 Mar (h. 14.30 -17.30)  next exam sessions Q.1) (10 Points) In the graph here aside, a subject’s spirogram (spontaneous breath + full inspiration + forced expiration ) is shown. …/ 3 – 1.a) Draw in the box the tracing of the flow signal , indicating exactly, for each sample indicated in the previous graph, the values of the corresponding flow and the shape of the signal. Provide a comment on how did you obtain the resul t. ………………………………… ………………………………… ………………………………… ………………………………… ………………………………… ………………………………… ………………………………… ………………………………………………………………………………………………… … … ………………………………………………………………………………………………… … … …………………………………………………………………………………………………. .… .. …………………………………………………………………………………………………. .… .. …………………………………………………………………………………………………. .… .. …………………………………………………………………………………………………. ..… .. 0 0.5 1.0 1.5 2.0 2.5 -0.5 3.0 3.25 -0.75 Volume variation (L)time (sec) 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00 Flow (L/sec)time (sec) 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00 …/ 3 – 1.b) De fine and calculate the following parameters for the subject considered before : Definition Value (measurement units) VT ……………………………………….……………… ……………………………………….……………… fB ……………………………………….……………… ……………………………………….……………… V’ E ……………………………………….……………… ……………………………………….……………… IC ……………………………………….……………… ……………………………………….……………… IRV ………………………………… ……. ……………… ………………………………… ……. ……………… ERV ………………………………… ……. ……………… ………………………………… ……. ……………… FVC ………………………………… ……. ……………… ………………………………… ……. ……………… FEV 1 ………………………………… ……. ……………… ………………………………… ……. ……………… PEF ………………………………… ……. ……………… ………………………………… ……. ……………… FEF 50 ………………………………… ……. ……………… ………………………………… ……. ……………… FEF 25-75% ………………………………… ……. ……………… ………………………………… ……. ……………… …/ 2 – 1.c) According to the spir ometric values obtained during the test, does the subject show an obstructive or a restrictive pattern? Why? ………………………………………………………………………………………………… … … ………………………………………………………………………………………………… … … …………………………………………………………………………………………………. .… .. …………………………………………………………………………………………………. .… .. …/ 2 – 1.d) Draw in the following box the flow -volume curve , indicating all the points during inspiration, expiration, and tidal breathing. Q.2) (8 Points ) During an incremental exercise test , V T (tidal volume), f B (breathing frequency), ������������̅,������2 (mean expiratory fraction of oxygen), ������������̅,������������ 2 (mean expiratory fraction of carbon dioxide) are measured. …/ 3 – 2.a) Complete the following table by calculating oxygen consumption (V’ O2), CO2 production (V’ CO2 ) and the Respiratory Exchange Ratio (RER) (assuming ������������,������2=0.21 and ������������,������������ 2=0): Exercise Workload (%max) VT (liters) fB (min -1) ��̅,������������ (adim) ��̅,������������������ (adim) V’ O2 (L min -1) V’ CO2 (L min -1) RER (rest) 0.5 12 0.18 0.025 ………. ………. ………. ………. ………. ………. 30% 1 15 0.17 0.03333 ………. ………. ………. ………. ………. ………. 50% 1.5 20 0.16 0.41666 ………. ………. ………. ………. ………. ………. 70% 2 25 0.15 0.04 ………. ………. ………. ………. ………. ………. 100% 2.5 25 0.15 0.06 ………. ………. ………. ………. ………. ………. …/ 1 – 2.b) Explain how the values have been calculated: ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. …/ 2 – 2.c) At which exercise workload the anaerobic threshold has been overcome ? Why? ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. …/ 2 – 2.d) What is the metaboli sm at rest based on ? Why? ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. Q. 3) (4 Points) …/1 - 3.a) Which are the differences between a pressure -, volume - and flow -type pbody plet hysmograph ? .……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. …/1 - 3.b) What is the measurement principle of a respiratory inductive plethysmograph ? .……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. …… ………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. …/1 - 3.c) What is the measurement principle of an opto -electronic plethysmograph ? .……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. …/1 - 3.d) What do the above cited three kinds of plethysmographs (body box, variable inductance, optoelectronic ) have in common ? In other words, why for all these measurement systems the term ‘plet hysmography ’ is used ? .……………………………………………………………………………………………………… .. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. Q. 4) (3 Points) …/ 1.5 - 4.a) Draw a symmetric model and an asymmetric model of the airway tree: Symmetric model Asymmetric model …/ 1.5 - 4.b) In relation to the previous question 4.a, provide some comments regarding the modeling of airway tree. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ………… …………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. Q. 5) (8 Points) Consider a patient under mechanical ventilation …/ 3 - 5.a) Draw the corresponding tracings of flow and volume in the following case s when the control variable of the ventilator is inspiratory low ( CONSTANT and equal to 0.5 L/sec) [T I=1 sec; and T E=2 sec] : compliance = 0.05 L/cmH 2O; resistance = 4 cmH 2O·s/L compliance = 0.025 L/cmH 2O; resistance = 4 cmH 2O·s/L compliance = 0.05 L/cmH 2O; resistance = 8 cmH 2O·s/L …/ 1 - 5.b) Provide explanation s on how the tracings have been obtained and a comment regarding the comparison of the three cases: ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Pressure (cmH2O) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 flow (L/sec) time (sec) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 volume variation (L) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Pressure (cmH2O) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 flow (L/sec) time (sec) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 volume variation (L) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Pressure (cmH2O) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 flow (L/sec) time (sec) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 volume variation (L) Consider a patient under mechanical ventilation …/ 3 - 5.c) Draw the corresponding tracings of flow and volume in the following case s when the control variable of the ventilator is inspiratory f low (INCREASING RAMP from 0 to 1 L/sec) [T I=1 sec; and T E=2 sec] : compliance = 0.05 L/cmH 2O; resistance = 4 cmH 2O·s/L complianc e = 0.025 L/cmH 2O; resistance = 4 cmH 2O·s/L compliance = 0.05 L/cmH 2O; resistance = 8 cmH 2O·s/L …/ 1 - 5.d) Provide explanation s on how the tracings have been obtained and a comment regarding the comparison of the three cases: ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Pressure (cmH2O) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 flow (L/sec) time (sec) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 volume variation (L) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Pressure (cmH2O) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 flow (L/sec) time (sec) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 volume variation (L) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Pressure (cmH2O) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 flow (L/sec) time (sec) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 volume variation (L) ADDITIONAL SPACE ………………………………………………………………………………………………… …….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ………………………………………………………………………………………………………. . ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. …… ………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ………… …………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. …………………… ………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………… ……………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ………………………………………… …………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. Bioengineering of the Respiratory System 6 Feb 2018 FAMILY NAME………………………… NAME ……………………………. MATR ………… ORAL:  …………………………  next exam sessions Q.1) (7 Points) One subject is asked to perform a maneuver of forced vital capacity. The maneuver is performed starting from FRC, then it is followed by a full inspiration at TLC, finally followed by a forced expiration down to RV. By means of a flowmeter, the flow trace reported here aside is obtained. …/2 - 1.a) Draw in a graph the precise trace of lung volume variations during the maneuver, indicating all the values that are calculated. …/3 - 1.b) It is known that, in the same subject, TLC = 8 L and tidal volume V T=0.6 L. Define and determine the following parameters: Paramet er Defini tion Value (with units) FVC ………………………………………………\ ……………… ………………………………………………\ ……………… FEV 1.0 ������������������\ ������ ������������������\ ������ PEF ������������������\ ������ ������������������\ ������ FEF25 -75 ������������������\ ������ ������������������\ ������ FRC ������������������\ ������ ������������������\ ������ RV ………………………………………………\ ……………… ………………………………………………\ ……………… IRV ………………………………………………\ ……………… ………………………………………………\ ……………… ERV ………………………………………………\ ……………… ………………………………………………\ ……………… IC ………………………………………………\ ……………… ………………………………………………\ ……………… …/2 - 1.c) Draw the tidal and maximal flow-volume diagram (both insp and exp). Consider tidal inspiratory and expiratory flow constant and equal to 0.2 L/sec. ………………………………………. ………………………………………. ………………………………………. ………………………………………. ………………………………………. ………………………………………. ………………………………………. ………………………………………. ………………………………………. ………………………………………. ………………………………………. ………………………………………. Q.2) (5 Points) …/2 – 2.a) What is the difference between relative and absolute measurements of lung volume? Which methods are used to measure relative and absolute lung volumes? ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ……………………………………………………….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. …/3 – 2.b) Describe in detail (principle of measurement and main equations involved) one of the methods used for measuring absolute lung volume. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. …………………………………………………………\ …………………………………………….. ………………………………………………\ ………………………………………………\ ……….. ………………………………………………\ ………………………………………………\ ……….. Q.3) (8 Points) Consider the following trace of flow (POSITIVE=inspiratory), provided at the airways of a patient in order to assess the elastic properties of his/her respiratory system by the flow interrupter technique (multiple occlusions). Hypothesize that the patient is at FRC at time t30 sec). …/ 1.5 – 3.a) Determine and draw the trace of lung volume variation in the considered interval (t=0-32 sec). ………………………………………………\ …. ………………………………………………\ …. ………………………………………………\ …. ………………………………………………\ …. ………………………………………………\ …. ………………………………………………\ …. ………………………………………………\ …. ………………………………………………\ …. …………………………………………………. ………………………………………………\ …. ………………………………………………\ …. Airway opening pressure is measured continuously during the whole maneuver. At time 0- (before the first inflation) pressure is equal to 0 (i.e., atmospheric). Pressure values successively measured just before all flow interruptions (times x-) and during all intervals where flow was interrupted are reported in the following table: Time (sec)