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Patient Managmenet 2
Ventilator Circuit basics, modes of mechanical ventilation, etc
Question | Answer |
---|---|
What is the humidity temperature range for humidification? | 31-35 degrees celsius |
How much dead space does the HME create? | 500-100 ml deadspace |
If you have a tidal volume of less than 400 the tidal volume goes directly to | active humidity |
What are contra indications for the HME? | presence of thick, copious, bloody secretions. Can create resistance. VTe is less than 70% of inhaled Vt or there is no ET cuff. Temperature below 32 degrees celcius. Spontaneous VE is greater than 10 L/M Aerosolized medication is given. A very small |
In order to do the leak test on the MA1 the following settings should be used. | Vt-200 ml Rate 12 bpm flow 40 LPM Pressure MAX All other parameters off |
To perform the leak test you should allow the ventilator to trigger occluding the wye and exhalation side of the circuit | Then, observe the pressure manometer and the pressure should plateau and hold |
Lost volume is | gas volume that does not reach the patient |
What can cause lost volume? | small circuit leaks gas leak at ETT cuff Tubing compliance or system compressibility |
Lost volume is not a concern when it is less than | 5% of the VT |
What is the compression factor for a neonatal circuit? | 1 ml/cmH20 |
What is the compression factor for a pediatric circuit? | 2 ml/cmH20 |
What is the compression factor for an adult circuit | 3 ml/cmH20 |
How do you find the circuit compression factor? (Cfac) | Put in the preset setting and occlude the wye only. Observe the PIP and exhalved VT. Calculate by exhaled Vt/PIP |
In order to calculate compressible volume | set the ventilator to appropriate patient settings and attach to patients airway. Observe PIP and spirometer. |
In order to then calculate the compressible volume (lost volume) | Circuit Compression Factor * (PIP-PEEP) |
The final step is to find the patients corrected Vt by | exhaled VT-Compressible volume |
Tubing compliance (Ct) is now | measured and corrected on most newer vents |
What are causes of the high pressure alarm going off? | Coughing secretions kink in tubing pneumothorax |
What are causes of low pressure alarms? | circuit disconnection cuff leak/tube too small chest tube leak Open lavage Port |
In control mode | the ventilator delivers a machine (preset) breath at a specific time interval |
In control mode the ventilator controls | rate, VT or pressure and the patient does not have control |
The control mode of the ventilator should only be used when the patient has been | properly medicated |
What are indications for control mode? | To provide full ventilatory support (patient fighting the ventilator, tetanus/seizures, complete rest, crushed chest injury/paradoxical movement) |
What is a complication of the control mode? | Patient is ventilator dependent |
In Assist Control Mode | the patient can control the rate, but the Vt or Pressure is controlled by the ventilator. A minimum rate is set |
What are indications of assist control? | To provide full ventilatory support |
What are the advantages of assist control mode? | Patients can control rate which controls VE, Low WOB |
What are complications of Assist control mode? | Hyperventilation (stress, anxiety, pain) |
For Intermittent Mandatory Ventilation the ventilator delivers a set number of | breaths at a set tidal volume or pressure but allows the patient to breath spontaneously in between at their own Vt. |
What is the indication of IMV mode? | To provide partial ventilatory support (post-op patients, weaning) |
What are the advantages of IMV? | Maintains muscle strength Facilitates Weaning Less positive pressure Reduces V/Q mismatch |
What are complications of IMV Mode? | stacking of breaths muscle fatigue increased work of breathing |
What Ventilator Settings are prescribed by the physician? | Mode, VT, Fi02 |
What are the basic ventilator settings/alarms? | mode, Vt, Rate, Flow,Fi02, I:E ratio, Sensitivity, FIO2 Alarm, High pressure alarm, Low pressure alarm, Low exhaled VT alarm. |
What is the basic setting for VT? | 10 ml/kg |
What is the basic setting for rate? | 8-12 breaths per minute |
What is the basic setting for flow? | 40-60 LPM |
What is the basic setting for Fi02? | 40% |
What is the basic setting for I:E | 1:2; 1:3 |
What is the basic setting for sensitivity? | Pressure trigger (-2 cm H20) Flow trigger (2-4 L/Min) |
What is the alarm setting for fi02? | +/- 5% |
What his the high pressure alarm setting? | 10-15 cmH20 above PIP |
What is the low pressure alarm setting? | 10-15cmH20 below PIP |
What is the low exhaled Vt setting? | 100 mL below exhaled vT *consider spontaneous VT *Check for leak |
Flow will affect | PIP |
For COPD patients you may choose to set the flow at | 50-60 LPM |
Positive End Expiratory Pressure | increases the end-expiratory pressure to a value greater than atmospheric |
What are the indications of PEEP? | TO improve FRC Improve oxygenation |
What are complications of PEEP? | worsens the effects of positive pressure, bauraotrauma, airtrapping, pneumothorax, decrease invenous return, decreased urine output |
What is the companion to PEEP? | COntinuous positive airway pressure |
CPAP | is applied to spontaneous breaths |
PEEP is used to help with | oxygenation |
What is the PEEP/Fi02 Rule? | If the patient is on greater than 60% fi02 without PEEP, add it in |
Before ventilators were designed that incorporated PEEP systems inside the unit PEEP was added | externally by placing a device on the expiratory limb of the patient circuit |
What are examples of external PEEP devices? | Underwater Seal, Water Column, Boehringer Valve, Spring loaded valve (Down's Valve) |
What is the pro of the underwater Seal PEEP system? | Low cost, non invasive |
What is the CON of the underwater Seal PEEP System? | loss of peep with evaporation Bubbling |
What is the emerson Water Column? | It is similar to the underwater seal but it's diaphram reduces bubbling |
The Boehringer Valve has a ball that | creates pressure |
What is the pro of the Boehringer Valve? | No H20 is needed |
What are Cons of the Boehringer Valve? | Must remain upright. PEEP only goes to a certain value. |
The Down's Valve and Spring valve are similar in that they | both contain a spring |
What is the pro of the spring/downs valve? | They work in any position |
What is the con of the spring/downs valve? | There is a limited amount of PEEP that can be reached |
What is the PEEP that can be achieved with the down's valve? | 2.5-15 cm H20 |
What is the PEEP that can be achieved with the screw down valve? | 0-20 cm H20 |
What is the formula to calculate Inspiratory Time (Sec(? | Vt/Flow (Flow must be converted to Liters per second) Vt must be in Liters. |
What is the calculation for RCT? | 60/Respiratory Rate |
What is the calculation for Et(Sec) | RCT-I time |
What is the calculation for I:E ratio? | IT/IT:Et/IT |
What is Peak Inspiratory Pressure? | The amount of pressure required to deliver the Vt overcoming the airway resistance. |
What is PIP used for? | to calculate dynamic compliance which is a reflection of lung compliance and airway resistance. |
The Ppl (plateau pressure) is | caused by inspiratory hold and stops flow. |
The Ppl corresponds with | Phase 2 of the respiratory cycle |
The Ppl is the | amount of pressure required to maintain lung inflation in the absence of airflow. |
How do you obtain the Ppl? | Inspiratory Hold which will lengthen the I time. |
Ppl is used to calculate | static compliance which is a reflection of lung complaince. |
What are other uses for an inspiratory hold? | Improve oxygenation, administer MDI therapy. |
Resistance holds no bearing on | plateau pressure |
What is Cdyn? | Reflects lung compliance and/or airway resistance. |
How do you calculate Cdyn? | Corrected vT/(PIP-PEEP) |
What is the normal values for Cdyn? | 30-40 ml/CmH20 |
What does Cstat do? | Reflects lung compliance only and cannot reflect airway reesistance because there is no gas flow. |
What is the formula for cStat? | corrected VT/(Ppl-PEEP) |
Compliance is equal to | Change in V/ Change in P |
Compliance reflects the | degree of lung volume per unit of pressure |
In a normal healthy patient Cstat is | 70-100 ml/cm H20 |
In a male on a ventilator Cstat should be about | 40-50 ml/cm H20 |
In a female on a ventilator Cstat should be | 35-45 ml/cmH20 |
cL is the abbreviation for | lung compliance |
What are conditions that decrease lung compliance? | Atelectasis ARDS Pneumothorax |
When there is a decrease in lung compliance | PIP and Ppl both increase. This in turn decreases static and dynamic compliance. |
An increase in airway resistance may be due to | bronchospasm kinking/biting of ETT Airway obstruction |
With an increase in Airway resistance there will be an increase only in the | PIP. Dynamic compliance will be decreased only. |
Airway resistance obsructs | airflow. |
Airway resistance is increased when | the diameter or patency of the airway is reduced |
Airway resistance can be caused by changes | inside the airway (retained secretions), in the wall of the airway (inflammation), or outside the airway (ie, tumors) |
What is normal RAW on an unintubated patient? | .6-2.4 cmH20/L/Sec |
What is the normal Raw on an intubated patient with a flow of 30 L/Min? | 6 cmH20/L/SeC |
How do you calculate Raw(cmH20/L/Sec) | PIP-Ppl/Flow(l/s) |
In order to calculate RAW flow must be in | Liters per second and constant. It is the limit variable. |
Waveforms are | graphical representations of the control or phase variables in relation to time. |
Observation and assessment of waveforms during mechanical ventilation can provide useful information, such as | inadvertant PEEP, WOB, resistance and compliance changes, patient/ventilator dyscynchrony, and leaks |
The descriptors used to describe each waveform are based upon their | respective shape |
What is the function of the expiratory retard and sigh controls on the MA-1? | The expiratory retard is a PEEP knob. The sigh controls are to give a large VT breath. |
The sources that illuminate the lights on the control panel of the MA 1 are | Assist Pressure Ratio Sigh Oxygen |
What is a range for Ppl to use on graphics? | 0.1-1.3 seconds and must correspond with Vt and Flow |
Adding an inspiratory hold or plateau will do what to inspiratory time? | increase |
Increasing the inspiratory rate on the MA-1 will do what to I time? | NOt change |
Increasing tidal volume on the MA-I will do what to the Inspiratory time? | increase |
Increasing the respiratory rate on the MA-I will do what to the I:E ratio? | decrease |
Increasing the respiratory rate on the MA-I will do what to the peak pressure? | NOt Change |
Increasing the tidal volume on the MA-I will do what to the peak pressure? | Increase |
Increasing the flow rate on the MA-I will do what to the peak pressure? | Increase |
In the presence of normal compliance and resistance an MA-I produces what kind of wave form? | Flow wave form |
What three factors impact I time? | Rate, VT and VE? |