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E. Calculate the alveolar ventilation for Lily and Jenna. Assume their dead spac

ID: 162230 • Letter: E

Question

E. Calculate the alveolar ventilation for Lily and Jenna. Assume their dead space is 175 mL. Compare them to a normal value (see table 17.4 of the textbook). Show your work.

F. Match the patients with their most likely “diagnosis”. Choose between the following conditions: normal, heavy exercise, moderate exercise, asthma attack, hyperventilation, hypoventilation, pneumothorax, and lack of surfactant. Explain your answers.

Breathing TV ERV IRV RV (br/min) Mike 25 3500 72S 575 1000 5800 ND Jenna 14 325 800 2400 2300 5825 42% 500 1500 3000 1000 6000 78% Lily 12 750 1400 2700 1000 5850 80% Richard 20 Beth 15 250 700 1450 500 2900 75% Arterial PCO2 Arterial pH Hong (mm Mike t 40.0 7.39 -4 -4 Jenna 39.6 17.41 -4 -4 ly 740 -4 -4 Richard 22.3 7.76 Beth 150.2 1.28 0 TV: tidal volume; ERV: expiratory reserve volume; IRV: inspiratory reserve volume RV: residual volume, TLC: total lung capacity; FEVI: forced expiratory volume in 1 second; 2: partial pressure of Co2; Pip: intrapleural pressure

Explanation / Answer

E.

VA= (VT - VD)* Breaths/min

Where,

VA= Alveolar ventilation (ml/min)

VT= Tidal Volume (ml)

VD= Physiologic dead space (ml)

For Lily,

VA= (500-175)*12

= 325*12

= 3900 ml/min

=3.9l/min.

For Jenna,

VA= (325-175)*14

= 2100 ml/min

= 2.1l/min

The normal value of alveolar ventilation at rest is 4.2l/min.

VA of Lily is 3.9l/min and Jenna is 2.1l/min.

This reduction in VA values would result in increased Arterial PCO2 and decreased Arterial PO2.