CCP 108 - Fundamentals Of Mechanical Ventilation Flashcards
Define “PEEP”
Peak End Expiratory Pressure
Prevents complete exhalation of volume to reduce atelectasis.
Define “SIMV”
Synchronized Intermittent Mandatory Ventilation
- Guarantees a MINIMUM set breath rate at set volume or pressure and allows patient triggered breaths with pressure support (usually lower to facilitate pulmonary PT)
- Patient triggered breaths are patient initiated and patient terminated
- Settings: Mode - SIMV/CPAP, Pressure/Volume
Breath rate: desired minimum, TV/Pressure control: desired for mandatory breaths, Insp time: desired per flow, Pressure support: desired insp support, O2 %: desired FiO2, Sensitivity: 1 - 9, PEEP - desired PEEP
Define “Pressure Support (PS)”
Pressure Support (PS)
- Supports patients inspiratory effort and reduces/prevents atelectasis with PEEP
- Breaths are patient initiated and patient terminated
- Settings: Mode - SIMV/CPAP
Breath rate: “–”, Pressure support: desired pres, O2%: desired FiO2, Sensitivity: 1 - 9, PEEP: desired PEEP - Apnea Backup: Volume/Pressure mode: desired Pressure/Vol
Define “NIPPV”
Non-Invasive Positive Pressure Ventilation
- Used for ventilation/BiPAP/CPAP with face mask
- Turns on leak compensator
- NIPPV button will continue to blink until PS and PEEP are set
- Settings: Mode - NIPPV
Pressure Support: desired Insp Support, PEEP: desired PEEP, Sensitivity 1 - 9 (if no pressure support entered = CPAP) - Apnea backup as set Volume/Pressure control & Breath rate if > 12/min
LTV 1000 vs LTV 1200
- Non-PEEP compensated vs PEEP compensated
ie: non-PEEP compensated you will need to set pressure support/control with ΔP + PEEP combined
PEEP compensated you set your desired pressure in Pressure support/control and the ventilator will deliver that pressure + desired PEEP
Define “Apnea Backup”
- If no breath detected within 20 seconds apnea backup will trigger and alarm will sound
- Default rate is 12 breaths/min unless breath rate is set higher (ie: NIPPV)
- Will use selected mode (Volume/Pressure) and entered value for any delivered breaths
Define “Bais Flow”
- Constant 10 LPM flow in the circuit
- Assists with patient breath triggering
Define “CPAP”
Continuous Positive Airway Pressure
- Continuous flow of air to splint alveoli open and prevent atelectasis
- Used with face mask ventilation
List the items needed to set up the LTV Ventilator
- LTV 1000 or 1200
- Battery pack and/or AC Power for LTV
- Ventilator circuit (LTV 1000 style)
- x2 Heat/Moisture Exchanging (HME) filters
- EtCO2 filter line
- Balard ETT suction with corrugated tubing
Can you use a LTV 1200 vent circuit on an LTV 1000
No, there is no CPAP valve on a LTV 1200 type vent circuit
What is the difference between an adult and pediatric ventilator circuit
The pediatric ventilator circuit is smaller tubing to reduce circuit dead space
What did Dr. Eric Vu say regarding mechanical ventilation?
“There is nothing good that comes from Mechanical Ventilation”
What ventilator did BCAS CCP’s use before the LTV?
- Autovent 3000
- AKA “The Lungbuster 3000”
How did BCAS get the first LTV’s?
- BCAS was repatriating a patient from BC to the USA, after seeing the need for equipment the patients father bought BCAS 2 LTV’s
What effect can mechanical ventilation have on cerebral hemodynamics?
- High PEEP causing decreased venous return resulting in decreased MAP and CPP
- Cerebrovascular constriction due to too little CO2
- Ventilator asynchrony increasing pain/anxiety
What effect can mechanical ventilation have on cardiovascular system?
- Decreased venous return = decreased preload
- Hypotension
- Increased myocardial O2 demand
- Can IMPROVE left ventricular function due to it no longer needing to overcome negative pressure in thorax
What effect can mechanical ventilation have on respiratory system?
- Barotrauma
- Volutrauma
- Atelectotrauma
- Biotrauma
- O2 Toxicity
- Acid/Base balance
What effect can mechanical ventilation have on GI/GU system?
- Renal Failure due to decreased blood flow, hypoxia, hypercapnia or inflammation due to tidal volume
- Infection due to hypomotility of GI system
- Ulcers due to hypoperfusion of gut
To what values do we set our High pressure/Low pressure/Low Minute volume alarms on the LTV
- High Pressure: 10 mmHg over PIP levels
- Low Pressure: 5 mmHg above current PEEP value
- Low Minute Volume: 10% below our current VE value
Define “Pressure Control (PC) and Assist/Control Pressure (AC-P)”
Pressure Control (PC) and Assist/Control Pressure (AC-P)
- Mandatory breath rate set Pressure (volume is variable), machine initiate and machine terminated, can allow patient breaths if in AC-P
- In AC-P patient triggered breaths are patient initiated and machine terminated
- Settings: Mode - Assist/Control, Pressure
Breath rate: desired rate, Pressure control: desired pressure, Insp time: desired per flow, O2 %: desired FiO2, Sensitivity: (PC: “-“, ACP “1 - 9”), PEEP - desired PEEP
Define “Volume Control (VC) and Assist/Control Volume (AC-V)”
Volume Control (VC) and Assist/Control Volume (AC-V)
- Mandatory breath rate set Volume (pressure is variable), machine initiate and machine terminated, can allow patient breaths if in AC-V
- Complete Inspiratory hold to determine P plat and ΔP
- In AC-V patient triggered breaths are patient initiated and machine terminated
- Settings: Mode - Assist/Control, Volume
Breath rate: desired rate, Volume control: desired volume, Insp time: desired per flow, O2 %: desired FiO2, Sensitivity: (PC: “-“, ACP “1 - 9”), PEEP - desired PEEP
Define “PIP”
- Peak Inspiratory Pressure
- PIP = Flow x Resistance + alveolar pressure
- Ideally kept <35 cmH2O to prevent lung injury
Define “P plat”
- Plateau Pressure
- An approximation for alveolar pressure
- Ideally kept <30 cmH2O to prevent lung injury
Define “ΔP”
- Delta Pressure
- The difference between P plat and PEEP
Define “Vt”
- Tidal volume
- Volume of delivered air, measured in millilitres (mL)
Define “VE”
- Minute volume of exhaled air, measured in litres (L)
- Calculated based on last 8 breaths
Define “Vte”
- Tidal Volume Exhaled
- Volume of exhaled air, measured in millilitres (mL) at end of expiration
Define “f”
- Breath frequency, the number of machine and patient triggered breaths
Define “I:E”
- Inspiratory/Expiratory ratio, normal I:E = 1:4
What settings are used to complete a recruitment maneuver?
- Pressure Control Mode
- Breath Rate: <10
- Inspiratory rate: >1 second
- Pressure control and PEEP to get PIP to 40cmH2O
- Clamp endotracheal tube for 40 seconds
- Monitor vital signs and treat hypotension if required
When a ventilator alarm sounds what should you do first?
- Check the patient and work backwards towards the ventilator
What causes the “High Pressure” alarm and what will it to?
- Causes: tube/circuit occlusion/kinking, ventilator asynchrony, pneumo thorax
- When the High Pressure value is reached the ventilator will “dump” the breath and prevent exceeding that value
What causes the “Low Pressure” alarm?
- Causes: endotracheal tube cuff rupture, endotracheal tube dislodgement, circuit disconnection, open cap/port
Define “vCalc”
- Calculated flow rate of delivered breath in millilitres (mL)
- vCalc = Vt x Insp time
- Normal value 50-60ml
What causes the “Low Minute Volume” alarm?
- Calculated minute volume drops below set level
- Check patient
Define “Barotrauma”
- Caused by ventilation with too much pressure
- Can be caused even with low volumes
Define “Volutrauma”
- Caused by ventilation with too much volume
- Related to poor distant ability of lung tissues
Define “Atelectotrauma”
- Repeated opening and closing of alveoli causing shear stress and trauma
- Prevented with PEEP
Define “Biotrauma”
- Inflammation and cytokine release due to mechanical stress and Atelectotrauma
