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Mech/Vent Unit 5
SPC Mechanical Ventilation Unit 5 Exam 3
Question | Answer |
---|---|
What do you do if plateau pressures are >30? | Immediately Lower Tidal Volume |
Too high of a rate or frequency doesn't allow what? | Time for full exhalation and may cause "auto-trapping/auto-PEEP" |
FiO2 >50% increases risk of what? | Oxygen Toxicity and Intrapulmonary Shunting |
What is PEEP? | Airway pressure at which inspiration begins and exhalation ends. "When baseline pressure are above zero" |
What is CPAP? | The positive baseline pressure continuously applied to th airway of a SPONTANIOUSLY breathing patient. |
PEEP and CPAP are used to increase what? | Functional Residual Capacity (FRC) This will increase Mean Airway Pressure (MAP) and improve oxygenation. |
What 4 things does PEEP do specifically? | 1. Keeps alveoli from collapsing at end-expiration 2. Can reopen alveoli that have already collapsed 3. Increase Lung Compliance 4. Improves Gas exchange |
What are the 5 indications for PEEP? | 1. PaO2 <60mmHg 2. P(A-a)O2 >300 on 100% FiO2 3. Refractory Hypoxemia 4. Shunt of >30% 5. Recurrent atelectasis with low FRC |
What are Relative contraindications of PEEP? | Hypovolemia- which may reduce CO and lower BP |
What are Absolute contraindications of PEEP? | Untreated significance pneumothorax and tension pneumothorax |
What is Extrinsic PEEP? | PEEP that is set on the machine |
Intrinsic PEEP is also known as what? | Auto-PEEP |
What is Intrinsic/Auto-PEEP? | The amount of pressure in the lungs at the end of expiration when expiration is incomplete. |
What 6 factors lead to auto-PEEP? | 1. Ventilation-associated 2. Disease-associated 3. High Inflation Volume 4. Rapid Respiratory Rate 5. Relative decrease in exhalation time relative to inspiration time 6. Airway Obstruction |
Cardiac consideration for PEEP | As PEEP increases so does thoracic pressure. This will decrease venous return and lower CO & BP |
Oxygen Transport considerations for PEEP | As PEEP increase so does CaO2 and Oxygen Transport improves. |
What happens with CMV-AC mode? | All breaths are mandatory & vent controls timing, tidal volume, & pressure. Can be timed or patient triggered. |
CMV/AC mode is used on what patients? | The sickest patients to guarantee a minimum VE |
What are 4 issues with CMV-AC mode? | 1. Inappropriate Sensitivity settings 2. Response Time 3. Respiratory Alkalosis 4. Muscle Atrophy |
What happens with VC-CMV mode? | Tidal Volume is constant, PIP is variable, Flow, Rate & I-Time is set |
What happens with PC-CMV mode? | PIP is constant, Tidal Volume and Flow is variable, Rate & I-Time is set |
What 4 things should be known about Pressure Control Ventilation (PCV)? | 1. Helps prevent lung trauma (barotrauma) 2. may require sedation 3. tidal volume varies 4. spontaneous breathing patient may fight gas delivery. |
What is the primary use for Pressure Control Inverse Ratio Ventilation (PCIRV) mode? | Used to treat Acute Respiratory Distress Syndrome (ARDS) |
What 4 things should be known about (PCIRV) mode? | 1. TI is set longer than TE. 2. May improve oxygenation by increasing mean airway pressure. 3. Prevents full exhalation causing air-trapping/intrinsic/ auto-PEEP. 4. Uncomfortable and require sedation and sometime paralysis. |
What happens with SIMV mode? | f and VT or pressure is set. Vent delivers breaths in synchrony with patient’s inspiratory effort. Assist window. During spontaneous breaths, patient sets rate and volume (usually with pressure support ventilation (PSV) to reduce WOB). |
You should always use what when using SIMV mode? | PSV Pressure Support Ventilation |
CPAP is for what kind of patients? | Spontaneously breathing patients |
What happens in CPAP mode? | May improve oxygenation, used prior to extubation and liberation from ventilator, always have back-up ventilation settings in case of fatigue or failure |
What happens in PSV mode? | Augments patients spontaneous inspiratory effort. |
T/F PSV mode should be added to CPAP mode during weaning. | True |
Proportional Assist Ventilation (PAV) is based entirely on what? | WOB and Inspiratory effort |
What happens in PAV mode? | Weans until patient is doing all of the work of breathing. |
What 4 settings mean the same thing? | Pressure Regulated Volume Control (PRVC), Autoflow, Volume Control (VC), Adaptive Pressure Ventilation (APV) |
What happens in APRV mode? | 1. Provides two levels of CPAP 2. Allows spontaneous breathing 3. Most of the time is spent at higher level of CPAP. Pressure “released” just long enough to decrease lung volume and eliminate CO2. |
What 3 things should be known about APRV mode? | 1. Short release time creates intentional auto-PEEP. 2. After short release, pressure is returned to set upper pressure. 3. Increases MAP and has been proven to improve PaO2, reduce physiologic dead-space ventilation and reduce PIP. |
Settings in APRV mode include? | FiO2, T-high, T-low, P-high, P-low, and no set rate |
APRV is also known as what? | Bilevel |
What is APRV used for? | Refractory hypoxemia and non-compliant lungs. (i.e. ARDS) |
What happens in HFV mode? | HFV delivers a small amount of gas at a rapid rate (as much as 60-100 breaths per minute.) Tidal volumes < anatomical dead space. |
What is required with HFV mode? | Sedation and Pharmacological Paralysis |
When is HFV mode used? | Used when conventional mechanical ventilation would compromise hemodynamic stability, or for patients who are at high risk for pneumothorax |
What are the 4 patient advantages of using HFV mode? | 1. Microsurgery of URT (upper respiratory tract). 2. ARDS - to reduce the risk of barotrauma. 3. Fistulas (B-P, T-E) - when large leaks are present. 4. To reduce cardiovascular side effects. |
What are the 3 patient disadvantages of HFV mode? | 1. Special cannulas/ET tubes required 2. Special ventilators 3. Increased staff training |
What are 3 complications of HFV mode? | 1. Poor humidification 2. Necrotizing Tracheobronchitis 3. Tracheal tissue trauma |
What happens in HFOV mode? | 1. Uses very low tidal volumes at fast rates as well 2. A diaphragm or piston in the ventilator causes vibrations or “oscillations” to produce frequencies in excess of 50Hz or 300 breaths/min |
HFOV mode uses what approach? | Uses “open lung approach”-alveoli are opened and the patency of the alveoli are maintained |
What is known of HFOV? | Bias Flow - continuous flow of warmed humidified gas through circuit establishes MAP (like flowby). Facilitates elimination of CO2 and prevents drying of mucosa (secretions) |
What is the key in HFV & HFOV? | MAP key to Oxygenation |
Because of higher rates, tidal volumes are usually smaller than deadspace. Therefore, elimination of CO2 comes from a what in rate. | Decrease |
CPAP mode is acceptable to be used when the patient? | 1. Has Oxygenation issues 2. OSA Obstructive Sleep Apnea 3. Ventilate Fine |
BiPAP mode is acceptable to be used when the patient? | 1. Doesn't tolerate CPAP, more comfortable 2. Need ventilator support 3. Higher pressure requirements |
IPAP is set to what to increase what? | PIP to increase volume |
EPAP is set to what to improve what? | PEEP to improve Oxygenation |
What are the 4 BiPAP settings? | IPAP, EPAP, Rate, FiO2 |
In BiPAP rate is set for what? | To decrease WOB |
In BiPAP FiO2 is set for what? | To improve Oxygenation |
How is BiPAP different than CPAP? | Provides positive pressure during inspiration and expiration. |
What is the difference between IPAP/EPAP? | Pressure Support |
T/F Mouth piece ventilation is relatively new? | True |
What is mouth piece vent used to treat? | Muscular Dystrophy & ALS |
Benefits of mouth piece ventilation? | Does not require airway, patient can talk |
Increased flow rates lead to what? | Increased airway pressures which can cause barotrauma |
Describe Square Wave | Flow accelerates very quickly and reaches a set flow which is maintained throughout inspiration. Allows for an adequate I:E ratio with a normal flow rate. This optimization of I:E ratio is beneficial for those patients in which air trapping is a concern |
Square Wave is beneficial for patients with what? | COPD & Asthma |
Describe Sine or Sinusoidal Wave | Flow slowly accelerates to a peak flow and tapers off towards the end of expiration. |
What to know of Square Wave | Allows for an adequate I:E ratio with a normal flow rate. This optimization of I:E ratio is beneficial for those patients in which air trapping is a concern |
What to know of Sine Wave | Peak airway pressures are minimized. Sine waves are considered normal flow waves. This wave can be used if high peak airway pressures are encountered using the square wave. |
Describe Descending Wave | Utilizes a rapid acceleration of flow followed by a gentle tapering. |
T/F Descending Wave is most commonly used? | True |
What to know of Descending Wave | May require much higher flows to obtain an adequate I:E ratio. It is important to monitor the arterial blood gases of these patients to ensure an adequate ratio is being obtained. |
What is the Sensitivity setting? | The setting determines how easily a patient can trigger or initiate a machine delivered breath. |
What happens if the sensitivity dial is turned all the way off? | No amount of patient effort will initiate a machine breath, and the machine is in the controlled ventilatory mode. |
What happens if the sensitivity dial is turned all the way on? | The vent can auto-cycle or chatter |
What is Pressure Sensitivity Triggering? | Occurs when a patients inspiratory effort causes a drop in pressure within the circuit and when this drop in pressure is sensed by the pressure sensing mechanism of the ventilator, the ventilator triggers on and delivers a breath. |
What is important to remember about patient sensitivity triggering? | Setting this too high requires more patient effort to trigger the machine |
What is Flow Sensitivity is usually set how? | At continuous flow of 5 - 6 L/m through circuit with a sensitivity of 2 - 3 below this baseline to trigger breath |
Where is Low Pressure alarm set? | About 10 cm/H2O below PIP |
Where is High Pressure alarm set? | About 10 cm/H2O above PIP |
Where is Low PEEP/CPAP alarm set? | About 2-3 cm/H2O below set level |
Where is the high rate alarm set? | 10-15 above total |
Where is the Apnea alarm set at? | At no more than 20 seconds |
How do you prepare for final vent set up? | 1. Ensure Vent is working 2. Check humidifier or add HME 3. Set initial startup parameters (as ordered or per protocol) 4. Adjust Alarms 5. Emergency Airway Tray 6. Suctioning Equipment 7. ECG monitor 8. Resuscitation bag & mask |