(A) List 2 causes for this end-tidal CO2 pattern.

(B) List 2 causes for this end-tidal CO2 pattern

(C) Draw and label a pressure-time ventilator waveform showing-

(i) normal followed by
(ii) increased airway resistance.

(D) Draw and label a pressure-volume loop (volume targeted ventilation) showing-

(i) normal lung compliance
(ii) decreased lung compliance
(iii) increased lung compliance.

(E) Draw and label the following for a patient with a large cuff leak-

(i) Flow-time waveform
(ii) Volume-time waveform

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College Answer

(A) List 2 causes for this end-tidal CO2 pattern.

♦  Kinked/partially occluded tube
♦  Foreign body in airway
♦  Obstruction of expiratory limb of breathing circuit
♦   Bronchospasm

(B) List 2 causes for this end-tidal CO2 pattern

♦  Decreased respiratory rate
♦  Decreased tidal volume
♦  Increasing metabolic rate (fever, shivering, etc)

(C) Draw and label a pressure-time ventilator waveform showing- (i) normal followed by
(ii) increased airway resistance.

pressure-time waveform from Question 30 - Paper 1 of 2011

(D) Draw and label a pressure-volume loop (volume targeted ventilation) showing-

(i) normal lung compliance
(ii) decreased lung compliance
(iii) increased lung compliance.

pressure-volume loop from Question 30 - Paper 1 of 2011

(E) Draw and label the following for a patient with a large cuff leak-

(i) Flow-time waveform
(ii) Volume-time waveform

flow and volume-time waveform from Question 30 - Paper 1 of 2011

Discussion

Helpfully, the college answer provides us with some model diagrams. Unhelpfully, the college question omits the EtCO2 curves. I have tried to put together some EtCO2 curves to remedy this. So long as everybody is aware that this is not the college image.

Though this is a simple pattern recognition question, some references seem in order. The following local chapters discuss waveform interpretation:

End-tidal CO2 patterns are also discussed on this website by Carefusion.