Pilbeam 1-4 Review questions.docx

Convert 5 mm Hg to cm H2O. (1 mm Hg x 1.36 cm H2O=) - correct answer 6.8 cm H2O. 1 mm Hg = ___ cm H2O - correct answer 1.36 cm H2O. The pressure difference between the alveolus and the body surface is? - correct answer (Pw) Transthoracic pressure. The pressure difference between the alveoli and the pleural space is? - correct answer (Pl) Transpulmonary pressure. The pressure difference between the airway opening and the alveolus is? - correct answer (Paw) Transairway pressure. The pressure difference between the airway opening and the body surface is? - correct answer (Ptr) Transrespiratory pressure. What is the definition of elastance? - correct answer The ability of a structure to return to its natural shape after stretching. What is the formula for compliance? - correct answer Compliance = the change in volume/the change in pressure. What are the other terms for airway pressure? - correct answer Mouth pressure, airway opening pressure, and mask pressure. Intra-alveolar pressure (in relation to atmospheric pressure) at the end of inspiration during a normal quiet breath is approximately? - correct answer 0 cm H2O Which of the following is associated with an increase in airway resistance? - correct answer Decreasing the flow rate of gas into the airway. Which of the following statements is true regarding negative pressure ventilation? - correct answer These ventilators mimic normal breathing mechanics. (e.g. Iron Lung) PEEP is best described as: - correct answer Positive pressure at the end of exhalation on a mechanical ventilator. Which of the following statements is true regarding plateau pressure? - correct answer Plateau pressure is used as a measure of alveolar pressure. One time constant should allow approximately what percentage of a lung unit to fill? - correct answer 63% of the volume to be inhaled. A patient has a PIP of 30 cm H2O and a Pplateau pressure of 20 cm H2O. Ventilator flow is set at a constant value of 30 L/min. What is the transairway pressure? (The difference between PIP and Pplateau.) - correct answer 10 cm H2O. Name a commercially available ventilator that is entirely pneumatically powered. - correct answer The Birdmark VII. Name some ventilators that are totally electrically powered. - correct answer Lifecare PLV-102, Pulmonetics LTV , AND Newport HT50. What type of ventilator delivers pressures below ambient pressure on the body surface and mimics the physiology of normal breathing? - correct answer Negative pressure ventilator. Explain the operation of an externally mounted exhalation valve. - correct answer The exhalation valve is mounted in the main exhalation line of the patient circuit. With this arrangement, an expiratory valve charge line, which powers the expiratory valve, must also be present. When the ventilator begins inspiratory gas flow through the main inspiratory tube, gas also flows through the charge line, closing the valve. During exhalation, the flow from the ventilator stops, the charge line depressurizes, and the exhalation valve opens. What volume displacement device creates a sine waveform for gas flow? - correct answer A non-linear rotary drive piston. A Drager Evita Infinity V500 ventilator is set to deliver a minute ventilation of 5 L/min. The patient breathes six times in 1 minute and receives a mandatory breath of 500mL with each breath. The ventilator detects the difference between the actual and the set minute ventilation and adds four more breaths (500mL each) to make up the difference. Which of the following best describes this type of ventilator? - correct answer A closed loop ventilator. The controls set by the ventilator operator are considered part of the: - correct answer User interface. The gas-conducting tubes that carry gas from the ventilator to the patient are referred to as the: - correct answer Patient circuit. A ventilator in which the gas that enters the patient's lungs is also the gas that powers the unit is referred to as a: - correct answer Single circuit ventilator. In a spring-loaded bellows volume-delivery device, the amount of pressure is determined by the: - correct answer Tightness of the spring.