Review Flashcards
Normal Neonatal Ti
0.3-0.4
Normal Vt for Neonatal
5 ml/kg
Venoarterial (VA) ECMO
Will offload both the heart and the lungs
Single Site Approach to Venovenous ECMO Cannulation
A dual lumen cannula is inserted into the jugular vein
Venous blood is withdrawn through one lumen that has ports in both superior and inferior vena cava
Reperfusion will occur in second lumen located in right atrium and will dump blood into the right ventricle, this is designed to reduce recirculation of blood
How Long is ECMO Used for Compared to Cardiopulmonary Bypass
ECMO is a longer therapy compared to cardiopulmonary bypass
Cardiopulmonary bypass is only used for hours
ECMO can be used for up to 10 days
What is the Main Reason Why ECMO is Use in Neonates
PPHN which results from different diseases such as pneumonia, MAS, RDS
CHD
What is the Main Reason Why ECMO is Use in Adults
Severe Asthma and ARDS
What are the risk factors that are associated with ECMO
Bleeding
Thrombosis
Infection
DIC
Nova Lung
Provides pumpless arterio-venous extrapulmonary lung support, because it is pumpless the blood pressure of the patient is needed to circulate the blood
Uses diffusion to provide oxygenation and ventilation
Venovenous (VV) ECMO
Will only support the lung
Venous blood will be divided into two semi-permeable membranes, and gas exchange will occur along the membrane
Indication for ECMO
Potentially reversible severe cardiac or pulmonary failure that is unresponsive to other treatment
Hyoxemic Resp Failure
Hypercapnic respiratory failure with an arterial pH <7.20
Refractory cardiogenic shock
Cardiac arrest
Failure to wean from cardiopulmonary bypass after cardiac surgery
As a bridge to either cardiac transplantation or placement of a ventricular assist device
Independent Lung Ventilation
A double lumen will allow for separate ventilation of each lung which can be done synchronously or asynchronously
Prone Positioning Indications
Severe ARDS-Main
Acute lung injury where there is V/Q mismatching
Cardiogenic pulmonary edema
Pneumonia
Pulmonary embolism
Prone Positioning Absolute Contraindication
Acute Bleeding
Spinal instability
Pregnancy in the third trimester
Increased ICP
Traction
Weight > 136 kg
Unstable sternum (open heart surgery)
Ventricular assist device
Intraortic balloon pump
Prone Positioning Relative Contraindication
Multiple trauma
Continuous renal replacement therapy
Temporary pacemaker
Hemodynamic instability
Large abdomen
Gross ascites
How to Position the Prone Patient
Reverse trendelenburg, 30 degrees if possible in order to limit risk of aspiration
Use pillows/positioning devices to maximize diaphragmatic excursion
According to AHS How Long Should We Prone
Prone 3 hours and supine 1
Discontinuation of Proning
FiO2 < 0.60
Deterioration of patient status related to prone position
Positioning demonstrates no improvement in patient status or becomes no longer beneficial
Airway Pressure (Paw)
Paw=Ptp - Ppl
Reflects pressure required to inflate both the lungs and the chest wall
Paw Measuremnets
Plateau pressure during inspiratory pause
Total PEEP during an expiratory
So Paw = Palv during pause maneuvers because there is no flow
Drawback of Airway Protective Ventilation
Assumes that pleural pressure is negitable
Pleural Pressure (Ppl)
Pressure in pleural space and will be affected in intra-abdominal pressure and decrease in chest wall compliance
This can be measured through esophageal pressure monitoring,
What will Increase Ppl
Anything that will increase intra-abdominal pressure
Obesity
Ascites
Ileus
Bowel Edema
Post Fluid Resuscitation
Transpulmonary Pressure
Requires the measure of esophageal pressure through a esophageal balloon
The Peso is though to represent Ppl
Esophageal Balloon Pressure Measurement
The catheter is measuring the pressure in the thoracic cavity and you need to subtract this from the pressure that the ventilator is giving you can isolate the pressure in the lungs
Ptp = Paw – Pe
Inserting Esophageal Catheter
Insert 60 cm and then pull back to 40 cm looking for cardiac oscillation
Can push on belly as a check to see temp spike in pressure
Performing an Esophageal Pressure Monitoring
Do an inspiratory hold to determine Ptp which can be used to make sure that the pressures are <30
Do an expiratory hold to see if Ptp is positive which is needed in order to maintain recruitment of alveoli
Bladder Pressure and Abdominal Pressure
Bladder pressure and abdmonial pressure are correlated and not predictive
When there is an increase in bladder pressure that is a red flag
Lung Volume Recruitment Manoeuvre
LVRM are used to open up alveoli with high inspiratory pressure and determine appropriate PEEP
One way to perform a LVRM is to use a high PEEP of 30-40 for 30-60 seconds and make sure to monitor vitals while you are doing this
LVRM Indication
CXR with bilateral infiltrates (AIL or ARDS)
Atelectasis
Increase OI
High PEEP
Suctioning/Discontection
Contraindication to LVRM
Pulmonary air leaks: Recent, active pneumothorax, PIE, etc
Bronchopleural fistula
Hemodynamic instability (eg. low BP)
Head Injury
Obstructive lung disease
Pregnancy
When to Stop a LVRM
SpO2 falls < 80%
MAP < 60 or 20% change from baseline
HR < 60 or 20% change from BL
New arrhythmia
APRV Definition
Inverse ratio, pressure controlled, and time cycled ventilation mode
Advantages of APRV
Lung protective, and can help oxygenation and ventilation
Easy to manipulate MAP and I:E
May be more comfortable as allow for spontaneous breathing (positive effect comes from spontaneous breathing)
Disadvantages of APRV
May result in muscle atrophy
Link Between Thigh and Expiratory Flow Rate
Tlow begins once Phigh is over and at this point the expiratory flow rate is highest at this point and equal to PEF
Tlow should terminate at the time that PEF is reduced to 25-50% of peak
Expiratory flow is not finished before inhalation occurs so that PEEP can be maintained
Total PEEP in APRV
Plow + Auto PEEP
Frequency in APRV
Frequency is 60 seconds divided by the sum of Tlow plus Thigh
APRV is most successful with a limited number of releases.
Ventilator frequency should remain around the 10- 12 range. Increases outside this range promotes derecruitment, and risks a return to refractory hypoxaemia.
APRV Settings When Switching From Conventional Ventilation
Phigh: Match Pplat on current mode (max 30 cmH2O)
Plow: Set to 0 cmH2O
Thigh: 4.0 sec
Tlow: 0.5-1.0 sec (often 0.8 sec)
I:E in APRV
4:1 or greater
We want to spend 90-95% of the time in Phigh
APRV Setting When Starting On APRV
Phigh: Set at 30 cmH2O
Plow: Set to 0 cmH2O
Thigh: 4.0sec
Tlow: 0.5-1.0 sec (often 0.8 sec)
Increasing Ventilation When On APRV
Decreasing PaCO2
Weaning sedation/increasing spontaneous ventilation
Increase Phigh (increase your Vt and MV)
Decrease Thigh
Optimize Tlow to between the 25-50%
Increase Tlow
Increasing Oxygenation in APRV
Increase FiO2
Increase Phigh
Increase Thigh
Decrease Tlow
Weaning of APRV
Weaning is achieved through decreasing Phigh and increasing Thigh to get a low CPAP
The minute volume generated by release volumes decreases and is gradually supplemented by increased spontaneous minute volume, until the patient has essentially been weaned to pure CPAP.
Barriers to the Use of APRV
Lack of clinician knowledge and comfort
Concerns about over-distension/over-stretching
No RCT showing improved outcome in humans (yet
May be contraindicated in air leak syndromes and conditions of TBI/high ICP due to hypercapania
Tube Compensation
Nullify the resistance imposed on the tube to help facilitate a proper SBT
Will be similar to pressure support
Reduce of risk of air trapping
Will set % of compensation you want and whether you want inspiratory and/or expiratory help
Assessing Optimal Tlow in APRV
Tlow should be re-evaluated every 1-2 hours for the first six hours as that is when the lung will undergo the most recruitment and we need to ensure that volumes do not exceed 8ml/kg
Tlow should also be re-evaluated after a change in the pressure setting
Why is ARPV Helpful in ARDS
ARDS reduces FRC and compliance and increases WOB
Applying Phigh will restore FRC and create a better pressure volume relationship to help faciliate spontaneous ventilation and oxygenation
Mean Airway Pressure in APRV
Mean Airway Pressure in APRV= (Phighx Thigh) + (Plow x Tlow__)
(Thigh+ Tlow)
Timing of APRV
Most effective as treatment for ARDS when used as initial mode of ventilation
May be used with the spontaneous breathing COPD pt
High Frequency Ventilation
Frequencies >150 bpm
Tidal volumes are so small that they can be smaller than deadspace
Frequency of HFV
Frequencies is measured in Hertz (Hz) which is cycles per second
1 Hz=1 cycle/sec=1 breath per second=60 bpm
What Are the Indications for HFV
Acute Lung Injury (Severe Oxygenation Failure)
Ventilation failure
Upper airway surgery and bronchoscopy
BP Fistula or pulmonary air leaks in neonates (eg. PIE)
High Frequency Jet Ventilation (HFJV)
Passive exhalation which means there is the risk of breath stacking
Combines the use of a jet ventilator and a conventional ventilator
The conventional vent provides the PEEP (which = MAP) and +/- sigh breaths and then the jet ventilator will pulse above this
High Frequency Oscillation (HFO)
Most common
Active exhalation
MMV
When the patient is breathing above the set MV the vent will only deliver pressure supported breaths
When the patient is not meeting the set MV the vent will deliver mandatory breath
ASV Breath
Based on set % MV
Mandatory breaths will be PRVC
Spontaneous breaths PS and volume targeted
% MV for ASV
Based on 100 ml/kg IBW for 100% setting
Normal Pt 100%
COPD 90%
ARDS 120%
Extra for hyperthermia with 10% extra per oC increase
Extra for altitude with 5% per 500 m above sea level
Add 10% when an HME has been added
Managing Severe Acidosis with ASV
Increase PEEP and/or FiO2
Increase %MV
Managing High Oxygenation Needs in ASV
Increase PEEP and FiO2
Managing High Respiratory Drive in ASV
Increase %MV
Managing Respiratory Alkalosis with ASV
Decrease %MV
Basic Theory of Jet Ventilation
The small Vt will move through the deadspace instead of pushing the deadspace in
Exhaled gas will cycle out through counter current
Equitment Needed for Neo and Ped Transport
O2 Supply and blender and O2 analyzer
Mech vent
Mechanical Resuscitator
Pressure monitor
O2 monitor (X2)
ECG
Suction
Intubation Equitment
Feeding Tube
O2 hood
O2 tubing
Hand held neb with tubing
Tank Calculation
Duration of Flow =
Oxygen Tank Conversion Factor * Remaining Tank Pressure (psi) / Continuous Flow Rate (L/min)
Oxygen Cylinder Conversion Factors
D Tank
D Tank = 0.16
Oxygen Cylinder Conversion Factors
E Tank
E Tank = 0.28
Oxygen Cylinder Conversion Factors
G Tank
G Tank = 2.41
Oxygen Cylinder Conversion Factors
H/K Tank
H/K Tank = 3.14
Oxygen Cylinder Conversion Factors
M Tank
M tank = 1.56
Total Arterial O2 Content
CaO2= (1.34 x Hb x SpO2) + (PaO2 x 0.003)
How to Determine Pt Inspiratory Flow
Flow= Volume (L)/time (min)
Determining the total flow in a high flow delivery device
If air/O2 is for example 30 then it is 8:1 so for every 1 litre of oxygen 8 L is being entrained into the device
for total flow add the two toegther (=9) and then multiple by the set flow
Calculating Flow in Liquid Oxygen System
Gas Remaining= (Liquid Weight [lb]) x 860/ 2.5 L/Ib
Duration of Contents (min)= Gas Remaining (L)/ Flow (L/min)
Remeber 1 L of Liquid O2 = 2.5 lb
Rigid Bronchoscope
Mainly used for removal of foriegn bodies
Parts of the Flexible Bronchoscope
Light Transmission Channel: Light source at distal end of bronchoscope
Visulization Channel: Has lens to produce an image at the proximal end
Working Channel: Suction, tissue sample, O2 administration
Indications for Bronchoscope
Bronchogenic Carcinomas
Investigation
Therapeutic
Absolute Contrindications for Bronchoscope
No consent
No driver
No garage
No ability to oxygenate/ventilate
Relative Contrindicationsfor Bronchoscope
Uncontrolled bleeding
Uncontrolled severe COPD
Uncontrolled hypoxemia
Unstablehemo-dynamics (arrhythmias etc.)
Complications of Bronchoscope
Hypoxemia & hypercapnea
Vasovagal response (Hypotension, Bradycardia)
Airway irritation
Epistaxis
Pneumothorax
Hemoptysis
Anticholinergic “drying” agent to decrease secretions
Atropine
Glycopyrrolate
Bronchoscope Premedication Administration
Prior to the bronchoscopy procedure, outpatients are admitted to a day stay unit & nursing staff help prepare them…
Ensuring the consent form is signed
Inserting an IV
Premedicatingif called for:
- Morphine
- Ventolin: prophylactic prevention of bronchospasm
- Atropine: decreases bronchial and salivary secretions & helps prevent bradycardia from excessive vagal stimulation
Bronchoscope Brushing
Usually performed for cytology or histology analysis
Bronchoscope
Transbronchial Needle Aspiration
Used to sample areas on other side of bronchial wall (extrabronchialor transbronchial)
Performed under fluoroscopy
Advanced through suction channel with needle retracted
On physician’s request, needle advanced exposing it past sheath
Manipulated by thumb control
Physician darts desired site
Syringe attached to proximal end of the needle to aspirate sample
Bronchial Alveolar Lavage
Performed when area sampled distal to segmental or sub-segmental bronchi in which bronchoscope is resting
Bronchoscope advanced and wedged totally occluding airway
On physician’s request 6Occ of sterile NS is instilled through suction channel
Often 30cc aliquots
Sample aspirated and collected in BAL trap (70ml)
Much of saline instilled recovered
If < 35 cc of NS recovered, another 60 cc of sterile NS instilled and aspirated again
Recovered sample contain cells for analysis
Samples sent to microbiology
Visually inspect for foamy head on sample indicating presence of surfactant and indicating good sample
BLES Dosing
5 ml/kg
