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RPC 180 Unit II
Mechanical Ventilation
Question | Answer |
---|---|
What is the formula to determine the Required FiO2? | Required FiO2 = Desired PaO2 * Known FiO2/Known PaO2 |
This FiO2 percentage is initially used to help relieve tissue hypoxia and/or calculate shunt… Until an ABG is performed to get more precise data | 50% to 100% |
What are the three measurements used to manipulate the I:E ratio? | 1) Peak Flow 2) Rate or (f) frequency 3) Tidal Volume |
The Manipulation of the I:E ratio is a function of these three measurements? | o Peak Flow o Rate or (f) frequency o Tidal Volume |
What happens to the Inspiratory & Expiratory Time if you increase the peak flow? | Inspiratory time will Decrease and the Expiratory time will increase |
What happens to the Inspiratory & Expiratory Time if you increase the frequency or rate? | You will increase the inspiratory time and decrease the expiratory time |
What is considered an acceptable I:E ratio for a normal patient when initially setting up a ventilator? | initial I:E ratio setting is 1:2 |
What is considered an acceptable I:E ratio for a COPD patient when initially setting up a ventilator? | I:E ratio for a COPD patient is 1:3 or 1:4 |
How is Minute Ventilation (V.E) calculated and measured? | It is calculated by multiplying the rate (F) times the Volume. It is measured in Liters per minute (LPM) |
What is a typical normal minute ventilation range? | Normal minute ventilation is about 5-6 L/min depending upon body size and oxygen consumption |
What levels of minute ventilation would be considered abnormal or would cause concern? | 10 LPM |
How do you determine the predicted minute ventilation for a male with normal lungs and a normal metabolic rate? A female with normal lungs and a normal metabolic rate? | For males you multiply the Body Surface Area (BSA) x 4. For Females it is the BSA x 3.5 |
How is the Body Surface Area (BSA) determined or how is it obtained? | By the Dubois Monogram |
If a 0patient is hyperthermic, do you change or compensate for the estimated minute ventilation? If yes how? | The estimated minute ventilation must be increased by 9% for every degree Celsius above normal (37 degrees C. Conversely with Fahrenheit above 99 you would increase it 5% for every degree above 99. |
What are the percentages for compensation if a patient is hypothermic? | The estimated minute ventilation must be decreased by 9% for every degree Celsius below normal and 5% for every degree below Fahrenheit |
Should the minute ventilation be adjusted in the presence of metabolic acidosis? If yes how? | In the presence of metabolic acidosis the minute ventilation should be increased by 20% |
In a metabolic acidotic patient, if you were seeing compensation, How would the CO2 be compensating in relation to HCO3? Would they be moving up or down? Would they be moving in the same or opposite directions? | IF you were seeing compensation, the CO2 would be moving in the same direction as the HC03, moving downward |
For seriously ill patients requiring MV, an initial setting of _________ to _________ times estimated minute ventilation is frequently used. | an initial setting of 1.5 to 2.0 times’ estimated minute ventilation is frequently used. |
How is the best way to provide adequate alveolar ventilation? | By providing an adequate Tidal Volume |
One of the biggest problems of Positive Pressure ventilation is? | Barotrauma |
How do you calculate an estimated tidal volume? | 8 to 12 ml/kg of ideal body weight |
What is one of the main reasons to maintain adequate tidal volume? | to maintain homeostasis and/or proper acid base balance. |
What is considered the "ideal" starting point for calculating tidal volume? | The midpoint range or 10 ml/kg of ideal body weight |
Name Two reason The tidal volume should not exceed 12 ml/kg of ideal body weight? | Higher than 12 ml/kg tidal volumes will generate higher thoracic pressures and may result in 1) barotraumas and/or 2) reduced venous return |
Tidal volumes below this amount should not be used? | 4 ml/kg of IBW |
If a low tidal volume of 4 ml/kg of IBW is prescribed for a patient, what other ventilator function usually accompanies this? | The Sigh mode |
If using the sigh mode, what sigh limit per minute is usually used in conjunction with low tidal volumes? | 1 1/2 to 2 times the tidal volume. NBRC usually uses 7 times per minute |
What is formula to caclulate Ideal Body Weight for a male? For a Female? | For a male it is 106 pounds for the first five feet, and 6 pounds per inch over 5 feet. For a female it is 105 pounds for the first 5 feet. and 5 pounds for every inch over 5 feet. |
What is the formula to calculate the respiratory frequency (f) or rate? | Minute Ventilation/Tidal Volume V.E/Vt I.e. V.E of 6 LPM = 6000 ml. Tidal volume of 500 6000/500 = (f) of 12 BPM |
What is the primary cardiovascular complication of mechanical ventilation? | Reduction of cardiac output |
Define Cardiac Output? | It is a measurement of how much blood the heart forces or injects per beat |
True or False: During spontaneous ventilation, the fall in intrathoracic pressure that draws air into the lungs also draws blood into the major thoracic vessels and heart | True |
True or false: With the Normal thoracic pump mechanism, the return of blood to the right heart and the stretching and enlargement of the right heart volume reduces right ventricular preload. | False: Right ventricular preload is not reduced but enhanced. |
True or False: With the normal thoracic pump mechanism, the stroke volume, or the amount of blood pumped per beat, also increases from the right heart. | True |
True or false: During exhalation, the return of blood to the left heart temporarily Decreases as blood from the right heart passes through the pulmonary circulation. (this is called left ventricular preload) | False, the return of blood to the left side of the heart temporarily increases. |
True or False: An increase in left ventricular preload increases left ventricular stroke volume (this is normal hemodynamic function and is a cyclical event – it maintains your cardiac output) | True |
True or false: During inspiration with positive pressure ventilation, the increased pressures are transmitted to the vessels and other structures in the thorax | True |