Final Flashcards
CBG Procedure
- Check medical history and confirm steady state of 20-30 min
- Obtain and assemble necessary equitment
- PPE
- Select site and warm to 42C for 10 min
- Puncture skin (<2.5 mm) with lancet
- Wipe away 1st drop of blood and do not squeeze
- Fill sample tube (75-100 mcl)
- Place metal flea in tube and mix sample
- Place cotton on site
- Analyze sample within 10-15 min
- Dispose of waste
- Document
How much blood should be obtained with CBG puncture
75-100 mcl
Relative Contraindications to CBG
Peripheral Vasoconstriction
Polycythemia caused by a shorter clotting time
Hypotension
CBG and Arterilization
CBG are only useful when properly warmed, in order to cause dilation of the underlying blood vessels and increase capillary blood flow well above what the tissues needs
Egan’s says warm to 42 Celcius
AHS does not give a proper number needs to be warmed
Blood gas values will be similar to arterial circulation which is why the sample is known as arterialized blood
When should a CBG not be done
Infant <24 hr old (poor peripheral perfusion)
Need for direct analysis oxygenation and arterial blood
CBG should not be performed in the following areas
Posterior curvature on the heel, can puncture bone
Heel of pt who has begun walking
Finger of neonates, can cause nerve damage
Swollen, cyanotic, poorly perfused, and/or infected tissue
Peripheral arteries
Number of CBG Punctures Allowed
Max number of puntures if 2 per heel as long as the heel is in good condition
CBG Order of Collection
- Blood Gas
- CBC
- Neonatal Screen
- Chemistry
CBG Analysis
Alternative to arterial access in infants and small children
Can help give estimates of arterial pH, PaCO2, but is little help in assessing oxygenation
Better than finger stick values
CB Troubleshooting
Most common error is inadequate warming of the site and squeezing the site. Squeezing the site will result in venous and lympathtic contamination. Both will result in inadequate tests.
The clinican must ensure adequate sample collection while avoiding air contamination and clotting
Advantage of Radial Artery
Collateral Circulation
Easy to palpatate, access, stabilize, and punture
No major nerves in close proximity
Disadvantage of Radial Artery
More likely to go into spasm due to the fact that it is more peripheral
There is a radial vein on either side of artery so may get a venous sample
The Only Absolute Contra-Indication of ABG
Skin Graft at Puncture Site
Plastic Vented Syringe
20-25 gauge
Prefilled with Heparin (1 000 U/ml) and higher Heparin (>10 000 IU/ml) may cause altered pH
Brachioradialis Tendon
Lateral to radial artery and inserts into styoid process of radial bone
Flexor Carpi Radialis Tendon
Medial to radial artery and inserts into second and third metacarpal
Flexor Pollicis Longus Tendon
Medial to radial artery beneath flexor carpi radialis and inserts into phalange of the thumb
Pronataor Quadratus Muscle
Lies posterior to radial artery
Periosteum of the Radius
If patient complains of a sharp pain during ABG puncture and a solid structure is encountered the needle may have made contact with this structure
Thrombocytopneia
Decreased platlet count
Relative Contraindications to ABG
*The need for ABG can outwieght any of these contraindications
Bilateral negative Allan Test
ANticoagulant or Thrombolytic Therapy
Coagulation disorder
Severe Hypotension
Deformities at puncture site
Raynaud Disease
Distal to surgical site
Artery Supply to Right Arm
Brachiocephalic artery from arch of aorta to right subclavian artery
Artery Supply to Left Arm
Via left subclavian artery dircetly off aorta
From subclavian artery to hand
The subclavian artery on both hand passes between clavicle and 1st rib to become axillary artery as it enters axilla and the brachial artery as it leave th axilla
The the elbow will become brachial arteryand then divides into ulnar and radial artery
Radial and Ulnar Arteries
Radial and ulnar arteries will meet in the palm of the hand at the superifical and deep palmar arteries
Radial Veins
2 small radial veins on either side of radial artery
Major nerves are seperated from artery by tendons at this optimal site
Lateral Cutaneous Nerve
Continuation of musculocutaneous nerve
Will pass over brachioradialis tendon
Median Nerve
Seperated from radial artery by the flexor carpi radialis tendon and deep to the pollocis longus tendon
Radial Nerve Superifical Branch
From back of the arm and is seperated from the radial artery by the brachioradial tendon and travel along the lateral side of the radius and wrist
Transporting the ABG Sample
If the analysis of the sample will take more than 10 min put it in the ice slurry
Why Advantage does an ABG have over CBG and Venous Sample
Venous samples will vary due to local tissue metabolism
Capillary samples are prone to venous admixture and air contamination
Deficient Sample Return
Slowly withdraw the needle
ABG Pre-Analytical Error
Air in Sample
Effect on Parameter: Decrease PaCO2, Increased pH
Increased low PaO2
Decreased high PaO2
ABG Pre-Analytical Error
Metabolic Effects
Effect on Parameter: Increased PaCO2, Decreased pH, Decreased PaO@
How to Recongize: Excessive time since collection and inconsistent with pt status
How to Advoid: Analye within 15 min, and place in ice slurry
ABG Pre-Analytical Error
Excess Anticoagulant (Dilution)
Effects: Decreased PaCO2, Increased pH
Increased low PaO2
Decreased high PaO2
Recognization: Visible heparin in syringe
Avoidance: Use samples with pre pared heparin amounts
ABG Pre-Analytical Error
Venous Admixture
Effect: Increased PaCO2, Decreased pH, Greatly lower PaO2
Recognize: Syringe failure to fill with pulsation
Advoidance: Advoid brachial nd femoral sites, do not aspirate sample, use short bevel
PaO2
Partial pressure of oxygen in arterial blood
Severe Hypoxemia: PaO2 < 40 mmHg
Moderate Hypoxemia: PaO2 40-60 mmHg
Mild Hypoxemia: PaO2 >60 mmHg
CaO2
Concentration of O2 in 100 ml of aerterial blood
Normal: 18-20 ml
What is Mixed Venous Oxygen Saturation
Percentage of oxygen bound to hemoglobin in blood returning to the right side of the heart and reflect the amount of oxygen left over after the tissues remove what they needs
Used to help recognize when the body is extracting more oxygen than normally
An increase in extraction is the bodies way to meet tissue oxygen needs when the amount of oxygen reaching the tissues is less than needed.
How to Obtain a True Mixed Venous Sample
A true mixed venous sample (SvO2) is obtained from the tip of the pulmonary artery catheter and includes all the venous blood returing from Superior vena cava, inferior vena cava, and coronary sinus
By the time the blood reaches the pulmonary artery, all venous blood has “mixed” to reflect the average amount of oxygen remaining after all tissues in the body have removed oxygen from the hemoglobin.
The mixed venous sample also captures the blood before it is re-oxygenated in the pulmonary capillary.
ScvO2 Measurement
ScvO2 = central venous sample.
An ScvO2 measurement is a surrogate for the SvO2.
Because pulmonary artery catheter use has declined dramatically, ScvO2 measurements obtained from internal jugular or subclavian catheters are often used
It may be used to identify changes in a patient’s tissue oxygen extraction. We usually assume (possibly incorrectly at times) that a blood gas sample obtained from the internal jugular or subclavian (which reflects only head and upper extremities) will have the same meaning as an SvO2.
What Does the SvO2 Show
Mixed venous oxygen saturation (SvO2) can help to determine whether the cardiac output and oxygen delivery is high enough to meet a patient’s needs.
It can be very useful if measured before and after changes are made to cardiac medications or mechanical ventilation, particularly in unstable patients.
Normal SvO2
Normal SvO2 60-80%.
Normal ScvO2 (from an internal jugular or subclavian vein) is > 70%.
Purpose of fenestration in a Trach
Allow the pt to talk and move air
Parts of a Trach Tube
Plastic Connector: Hook bag, ventilate
Radio Opacie Line: Check position
Cuff: Seal airway and allow ventilaiton
Pilot Balloon: Maintain cuff seal
Murphy: Allow breathing when other ports are occluded
TBI Protocol
PaCO2 35-40
Decreased PaCO2 will cause vasoconstriction and decrease cerebral blood flow (decrease ICP)
PaO2 80-120
VC CMV
Decreased Resistance
PIP Decreases
Use Equation for resistance and compliance when in volume control
VC CMV
Vt Increased
Everything will increase with the exception of Ve (I:E will increase)
PPV Increased Deadspace Ventilation
Normal Vd/Vt is 0.25-0.40, but will be increase to 0.4-0.6 when PPV is used
Distribution of PPV will go to the apices and less to the bases when compared to a spontaneous breath
VC CMV
Increased Resitance
Pip Increases
Correct Placement of ETT
Want 3-5 cm above carina as a buffer zone for when the tube moves with the neck
Compliance
A measure of distensibility of the lung
Normal is 60-100 mL/cmH2O
<25-30 cmH2O in ARDS
PC CMV
Delta Pressures
Resistance Decreases
Ti dyn Decreases
Flow Increases
VC CMV
PEEP Decreases
PIP Decreases
Pplat Decreases
Pmean Decreases
How to tell what changes in compliance and resistance will result in when in volume control
Use the compliance and resistance formulas
Auto PEEP in Volume Control
There is an increase in resistance which can be responsible for auto PEEP
Volume Control Set Controls
Control volume and flow so as lung mechanics change pressure will change
Because we are controlled volume and flow we are controlled minute ventilation
Set: Vt, RR, Flow, PEEP, Ti pause, FiO2
CvO2 Calculation
(Hb x 1.34) x SvO2 + (PvO2 x 0.003)
Shunt Fraction %
<10% Normal Lungs
10-19% Seldom Needs Ventilatory Support
20-29% May need CPAP
>30% Needs Ventilatory Support
Ventilatory Patameters Adult
Tidal Volume
6-8 ml/kg
May be as high as 10ml/kg for neuromuscular and post op pts.
Lung protective 4-6 ml/kg.
Ventilatory Patameters Adult
RR
12-16 bpm
Higher rates run the risk of air-trapping
Ventilatory Patameters Adult
Insp Time
0.8-1.2 s
I:E of 1:2 or lower
Try not to inverse unless you really need to affect MAP
Ventilatory Patameters Adult
PEEP
5 cmH2O
Typical start is 5 cmH2O
Aim for optimal PEEP
Increases typically made in increments of 2-3 cmH2O
Watch for CV compromise
Ventilatory Patameters Adult
Minute Volume
~ 100 mL/kg to start!
Also used: ♂- 4 x BSA
♀-3.5 X BSA
Febrile pt’s require higher MV
Adjusted based on PaCO2
Vt and Pplat
Plat < 25 cm H20 Vt should be 6-10 ml/kg
Pplat25-30 Vt should be ≤ 8 ml/kg,
Ppat≥ 30 Vt should be ≤ 6 ml/kg
Contraindications to PEEP
Increased ICP, untreated pneumo, hypotension
Weaning with SIMV
Weaning by SIMV with pressure support is better (reducing oxygen dependency) than SIMV alone.
Meta-analysis of volume-targeted ventilation demonstrated significant reductions in the duration of ventilation and pneumothorax, but the trials were small and of different designs.
Volume guarantee may provide more consistent blood gas control.
Ventilatory Parameters Neonate <32 Weeks
Mode
PRVC
If Leak > 40% may change to A/C PCV
if Neonate Ventilation there is a leak > 40% consider
larger ETT, extubationto NIPPVS, or A/C PC ventilation
Ventilatory Parameters Neonate <32 Weeks
Vt
4 mL/kg
What about deadspace?
- eg. Flow transducers, ETCO2
Ventilatory Parameters Neonate <32 Weeks
RR
40 to 50 bpm
Ventilatory Parameters Neonate <32 Weeks
Insp Time
0.30 sec
Adjust to reach equilibrium
Ventilatory Parameters Neonate <32 Weeks
PEEP
6 cmH2O
Increases typically made in increments of 1-2 cmH2O. PEEP may be 8 before alternative modes trialled.
Ventilatory Parameters Neonate <32 Weeks
Alarms
MV, VTe, VTi: +- 20%
RR total 90 bpm
HiP 35cmH2O, readjust to PIP +10 (G5 in APV will have the 10 buffer so you get an alarm when you are within 10 of high pressure alarm )
PEEP +- 2 cmH2O
Flow Trigg: 0.5 Lpm– 2 Lpm, assess for auto trigg
Apnea time; 5 – 10 sec
Apnea FiO2 (Match set on vent)
Neonatal VLBW ABG Goals
28-40 weeks GA
pH >7.25
PaCO2 45-55
PaO2 50-70
HCO3 18-20
SpO2 85-92
Neonatal ELBW ABG Goals
< 28 weeks GA
pH >7.25
PaCO2 45-55
PaO2 45-65
HCO3 15-18
SpO2 85-92
Modern Ventilators and Ventilating Different Pt Groups
- Most modern ventilators have the capabilities to ventilate all patient groups
- May require special equipment (eg. flow transducer)
- Consider the recommended weight ranges specified by the manufacturer!
- The patient ventilator circuit also varies with the patient type! Consider:
- Deadspace
- Compressible volume
- Humidity requirements
Main differences between a neonatal/pediatric and adult ventilator are the precision and ranges of:
Flow
Volume
Trigger sensitivity
Response time
Ranges of the settings
and…the modes available!
Cascade of Lung Injury
- FiO2and PPV start the cascade of lung injury (VILI) that leads to lung remodeling and chronic lung disease
- Lung disease is NOT homogeneous = PPV can cause over distension, and shear forces
- CPAP/PEEP is GOOD!
- Prevents surfactant deficient alveoli from collapsing
- Promotes alveoli recruitment, increases FRC
Least Traumatic Flow in P/V Curve
Least traumatic flow occurs in the middle of the P/V curve
When are lung most vulnerable to injury
during bagging, recruitment, and high pressure ventilation
Common Goals Across Patient Populations
- Provide adequate ventilation
- Provide adequate oxygenation
- Recruitment and maintenance of lung volume
- Improve FRC and lung compliance
- Appropriate WOB
- Support muscles of ventilation
- Use the correct balance of patient work vs. ventilator work
- Promote patient/ventilator synchrony
Provide adequate ventilation
Adjust alveolar minute ventilation to achieve the target PaCO2
VA= RR x (VT- VD)
Adjust/ensure VTwithin target goal
Adjust RR to achieve desired PaCO2
Mention that the Vt is less accurate in equation as Vdnot taken into account
Note: Ensure they assess if VT are appropriate before blindly choosing to change RR.
Permissive Hypercapnia
Ideally we want normal PaCO2 but sometimes it is unachievable without damaging the lungs
PaCO2 levels are allowed to rise as long as pH <7.25
Typically allow the rise to occur gradually
Sedation is required
Most often used in ARDS patients, but also COPD/Asthma
Contraindicated in head injuries, intracranial lesions, and cardiac ischemia/heart failure
PEEP and MAP
Intrinsic PEEP will increase MAP because of recruitemnt and increased FRV and improved C which will contribute to overall improved oxygenation and increased Map
Providing Adequate Oxygenation
Adjust the following to obtain target SpO2 (and/or PaO2)
- FIO2
- PEEP
- Increases MAP, recruits/stabilizes alveoli increasing SA for gas exchange, improves compliance, increases FRC
- MAP
- Typically via an increased inspiratory time, possibly even an inverse ratio
- NOTE: Inverse ratios are NOT used in neonates
- Note that as FIO2is increasing, PEEP should be increased
- Generally increasing TInot done until FIO2 >0.60 and appropriate PEEP set
Recruitment/ Maintenance of Lung Volume
Physiological PEEP
3-5 cmH2O
Maintains lung volume
Recruitment/ Maintenance of Lung Volume
Therapeutic PEEP
5-15 cmH2O is used to treat atelectasis and refractory hypoxemia
> 15 cmH2O is used for severe ARDS
Recruitment/ Maintenance of Lung Volume
Setting PEEP above LIP (or Above the LDEF)
Goal is “Open Lung Ventilation”
The theory states: to prevent de-recruitment, PEEP should be set above the LIP or above the lower deflection point
Need to do a static pressure-volume curve
Ensure that VTis adjusted so PIPs do not exceed the UIP
This setting is thought to give the best alveolar recruitment
Setting PEEP above LIP/LDEF really is to prevent collapse/de-recruitment (ie. It stabilizes those alveoli that open during the inspiration)
Set PEEP 2 cmH2O above LIP
Recruitment/ Maintenance of Lung Volume
Optimal PEEP
PEEP at which maximal respiratory benefits occur (lung mechanics, oxygenation) with minimal impact on the cardiovascular status
Finding optimal PEEP esophageal balloon or you could do a lung volume recruitment maneuver to get a flow volume loop and then look at the inflactionpoint
Pressure Volume Curve
Passive inflation of the lung in increasing increments of 50 – 100 ml
At each end point static pressure obtained (end insp pause) and plot a pressure volume curve.
Upper and lower inflection point can generally be determined
LIP thought to be where recruitment starts
UIP - Overdistention
Difficult and time consuming
Transmission of PEEP
The application of PEEP increases intrapleural and intrathoracic pressures
The extent of the transmission is dependent on:
- Amount of PEEP
- Lung compliance
- Low C (eg. ARDS): PEEP transmission significantly reduced
- High C (eg. COPD): PEEP transmission is highest
- Can be regionally affected due to disease process
- eg. pneumonia, atelectasis
- Thoracic compliance
- Hemodynamic compromise is most likely to occur when thoracic compliance is low (eg. Abdominal distension, thoracic deformities-eg. Kyphoscoliosis)
Stiff Lungs and PEEP Transmission
The stiffer the lungs the less easy the PEEP is transferred to affect hemodynamics more floppy lungs are more susceptible to changes in hemodynamics (COPD)
Lung Recruitment Maneuver Indications
CXR showing diffuse bilateral infiltrates = ALI/ARDS
Atelectasis
Increased OI (eg.> 12; may vary with institution)
Patients requiring a high PEEP
May also be done in patients who de-sat after disconnect/suctioning
Lung recruitment maneuvers are
Typically only done in adults!
Lung Recruitment Maneuver Methods
Patients should be adequately sedated
Many different procedures but generally involve high CPAP pressures (eg.30-45 cmH2O) for short periods (30 sec to 2 minutes)
The CPAP level is often based on a plateau pressure of a specified VT(ml/kg) (eg.12 mL/kg)
Ensure that the PEEP returned to is adequate
PEEP adequate as - above the LIP or the lower deflection point
Lung Recruitment Maneuver Contraindications
- Pulmonary air leaks:
- Recent, active pneumothorax, PIE, etc
- Bronchopleural fistula
- Hemodynamic instability (eg.low BP)
- Head Injury
- Obstructive lung disease
- Pregnancy
Lung Recruitment Maneuver Cautions
oWatch vital signs during maneuver
oWatch for hypoxemia
CHR P&P-D/c maneuver if SpO2 falls < 80%, MAP < 60 or 20% change from baseline, HR < 60 or 20% change from BL, new arrhythmia
FVS: When is it used?
Typical start-up strategy (as patient may be paralyzed/ sedated from intubation)
When patient is apneic
When we want the vent to do all the WOB
eg.Patient hemodynamically unstable, acute state of disorder (eg.ARDS, severe pneumonia)
PVS: When is it used?
When patients are spontaneously breathing
Patients with primarily hypoxemic respiratory failure
Weaning
Promotion of Patient/Ventilatory Synchrony
Sensitivity should be set at the most sensitive level that avoids auto-triggering
Patient triggering across populations:
Pressure triggering acceptable for pedsand adults
Neonates require flow or volume triggering
Minimize auto PEEP
The patient has to overcome the auto PEEP and more to create a negative pressure in the chest relative to the circuit, resulting in a triggered breath
This causes increased work to trigger the ventilator (regardless if P or flow triggering is used)
COPD applying PEEP can offset the autoPEEPbut in asthma applying PEEP is additive to auto-PEEP
Hyaline Menbrane Disease
Surfactant Replacement Therapy
May be intubated and then extubated to CPAP if stable
< 28 weeks should receive surfactant immediately post-birth
Hyaline Menbrane Disease
Lung Protective Strategy
Set PEEP for appropriate recruitment (CXR)
Permissive hypercapnia
VT~ 4 mL/kg
Goal pH ≥ 7.25
PaCO245-55 mmHg
Peak pressures should be < 25 cmH2O
Consider HFO for more severe cases/problems with oxygenation
Persistent Pulmonary Hypertension (PPHN)
PPHN=infants whose pulm. Vasculature remains constricted due to hypoxia and acidosis secondary to lung diesease, MAS, congenital pulm. Hypoplasia, polycythemia, CHD, sepsis, CHS disorders or metabolic abn(hypocalcemia or hypoglycemia)
Persistent Pulmonary Hypertension (PPHN)
Goals
- Older strategy: hyperventilate to PaCO230-35 and pH ~ 7.50
- New trend is target low/normal PaCO2(35-40) with pH 7.40-7.45
- Hyperoxygenateto PaO2> 100 mmHg and higher SpO2
- Nitric oxide therapy
Also, fluids/inotropes for good systemic pressures
PPHN Goals: 7.40-7.45 and CO2 35-40
Persistent Pulmonary Hypertension (PPHN)
To Meet These Goals
- Conventional mechanical ventilation
- HFO
- HFJV
- ECMO
Sildenafil sometimes used though CPS doesn’t list PPHN as an indication for the drug
Cyanotic Defects
Usually require a PDA for survival
Eg.Transposition, Tetralogy of Fallot, Hypoplastic left heart
Prostin– given via IV continuously to maintain PDA
Cyanotic Defects
Target ABG
Rule of 40’s:
pH 7.40, PaCO240’s, PaO240’s
SpO2 70-80%
These mimic in-utero conditions and maintain a PDA
Meconium Aspiration Syndrome (MAS)
- Surfactant replacement therapy (+/-)
- Lung protective strategy
- Appropriate VT’s
- Mild hyperventilation (low/normal CO2) andhyperoxygenateto treat concurrent PPHN
- Peak pressures should be < 25 cmH2O
- Watch for hyperinflation
- For more severe cases consider NO, HFO, HFJV, ECMO
- Avoid acidosis and hypoxemia!
- (This will increase PVR and potentially cause the development of PPHN)
Bronchopulmonary Dysplasia (BPD)= Chronic Lung Disease (CLD)
- Use the lowest FIO2 possible
- Later stages (confirmed BPD) maintain adequate oxygenation to prevent development of corpulmonale
- Surfactant therapy
- Done during the RDS stage…before true BPD
- Minimize mechanical ventilation
- Permissive hypercapnia
- VT4-6 mL/kg
- Goal pH ≥ 7.25
- Peak pressures < 25 cmH2O
- Permissive hypercapnia
- Once stable:
- Target lower SpO285-88% up to 94%
- Volume-targeted modes tend to work best for BPD.
Pulmonary Interstitial Emphysema (PIE)
- Reduce risk of barotrauma by using minimal ventilatory support
- Low VT’s (~4 mL/kg) with permissive hypercapnia (pH >7.25) and low pressures ( peak < 25 cmH2O)
- Position neonate with worst lung down
- Improves perfusion to promote healing
- Decreases ventilation to affected lung
- Severe cases:
- HFO or HFJV
- Selective intubation of good lung side
- Allows affected lung to collapse and heal
Congenital Diaphragmatic Hernia
Resuscitation
- Intubate immediately (avoid BVM); gastric tube
- Use 100% O2from beginning
- Connect to vent ASAP
Congenital Diaphragmatic Hernia
Ventilation Strategy:
- “Gentle ventilation”: AVOID vigorous chest rise
- Preserve spontaneous efforts (ie. Minimal sedation)
- Permissive hypercapnia
- Avoid high pressures (pneumothorax a strong marker for mortality)
- HFO and NO considered;
- ECMO in severe cases (often decided antenatally)
Congenital Diaphragmatic Hernia
ABG
PPHN very likely to coincide!
pH >7.25
Pre-ductal SpO2³85%, though ideal is 90-95%
Use preductal saturations to guide oxygen requirements
Preductal indicates oxygen delivery to the brain and therefore critical; postductalis non-cerebral and therefore less critical
NOTE: These babies have delayed transition from fetal circulation and it may take several hours to attain optimal oxygenation
Gentle Ventilation
The most important principle in the mangement of CDH
Preservation of spontaneous respirations and avoid neuromuscular blockades uses minimal sedation
Permissive Hypercapnia- No hyperventilation, no induced alkalosis
Avoid high ventilator pressures – pneumothorax can result from high pressures and is a very strong marker for mortality.
ABG and Post Ductal
Do not use post ductal O2 values to adjust ventilator settings
Use preductal oxygenation to guide oxygen requirements
Pre ductal Oxygen Levels
Indicate oxygen delivery to the brain via the carotid arteries and is therefore critical.
Ideal is 90-95%
Acceptable is >85% is the baby is otherwise stable (normal lactate levels)
Postductal Oxygen Levels:
Indicates non-cerebral oxygen delivery and less critical
Pediatric ARDS and Asthma
Same strategies as adults
Cystic Fibrosis
- Non-invasive ventilation the preferred method for ventilatory support
- Long-term prognosis decreases when patient is placed on conventional mechanical ventilation
- Pt with end-stage disease should not be intubated
- Concerns:
- Obstructive disorder \autoPEEP, hyperinflation…
- Allow for longer expiratory times!
- Predisposed to development of respiratory infections
Harmful Effects of Mechanical Ventilation
Respiratory Effects
- V/Q mismatching
- Increased intrapulmonary shunting, increased VD
- Decreased pulmonary perfusion
- VILI (ventilator-induced lung injury)
- Barotrauma,volutrauma, shear stress, atelectatrauma, biotrauma
- Air-trapping (autoPEEP)
- Increases risk of VILI
- Contributes to patient-ventilator dyssynchrony(which leads to increased WOB, increased need for sedation and longer weaning times)
- Oxygen toxicity
Harmful Effects of Mechanical Ventilation
Other systems
Renal, Liver, GI, Metabolism, Muscle function
Harmful Effects of Mechanical Ventilation
ICP and CPP
May decrease CPP 2°to decreased MAP
ICP increases 2°to an increased CVP
Harmful Effects of Mechanical Ventilation
Cardiovascular Effects
Decreased CO 2° to decreased venous return
Magnitude of effect depends on the transmission of P
Altered R and L ventricular function
Ways to Minimize the Harmful Effects
Set Appropriate PEEP
Want OPEN LUNG VENTILATION
Want to recruit and prevent de-recruitment (\set above LIP)
Ensure UIP not exceeded during inspiration
Ways to Minimize the Harmful Effects
Decrease Ventilating Pressure
As most of the harmful effects are a direct result of the positive pressure applied, the goal is to use the lowest minimal pressures (or VT) required
Ways to Minimize the Harmful Effects
Appropriate Ti and Te
- Ideally want pressure equilibration on inspiration
- Allow for complete exhalation to prevent autoPEEP
Ways to Minimize the Harmful Effects
Minimize length of mechanical ventilatory support
- Attempt to avoid ventilator dependence
- Attempt to minimize VILI and BPD
Oxygenation in Neonates
- BPD
- Associated with high concentrations of oxygen, PPV, endotracheal intubation, duration of therapy, fluid overload, degree of pulmonary prematurity…
- ROP
- A complication of prematurity
- Associated with duration of exposure to high PaO2
- Minimize by:
- Use lowest FIO2required
- Make changes in small increments
Harmful Effects of Mechanical Ventilation Specific to Neonates
- Intracranial hemorrhage
- Associated with mechanical ventilation but not necessarily caused by it (may be due to prematurity)
- Periventricular leukomalacia
- Softening of the white matter around the ventricles of the brain; associated with hypocarbiain preterm infants
- Minimize by:
- Maintain PaCO2at goal level
- Don’t over-ventilate when bagging! Try to use a vent ASAP after resuscitation.
Neonates Patient-Ventilatory Dssynchrony
- Vent not sensing pt. effort
- Vent not sensing due to leak (ETT)
- Minimize by:
- Ideally choose a newer ventilator with patient sensing
- Tailor the settings to the patient
- Remember: AutoPEEPwill also cause patient-ventilator dyssynchrony!
- (This is mostly an adult problem).
Neonates Ventilator Induced Lung Disease
- Chronic lung disease (BPD)
- Associated with prolonged PPV and oxygen toxicity
- Air-leak syndromes
- Pneumothorax/pneumomediastinum…
- PIE (Pulmonary interstitial emphysema)
- Much less common with today’s goal ventilatory parameters
- Minimize by:
- Use lowest pressures/volumes required
- Wean ventilator settings when appropriate
Respiratory Failure in Infants
pH <7.20
PaCO2 >60 mmHg
SaO2 <85% with FiO2 40-70% and CPAP 5-10
This means we should intubate
Infants on Mechanical Ventilation who have just been admitted into the NICU
Generally a pressure limited mode will be used with a sinsoidal flow
Ti and Surfactant Administration
If a longer Ti is requires before surfactant administration is should be lowered to 0.3 seconds after the surfactant is administered
Neonatal Mechanical Ventilator Modes
SIMV or assist control modes can help to reduce WOB and stabilize BP if properly set
Modes are generally volume controlled in order to reduce the risk of volutrauma (important with surfactant administration)
Spontaneous Parameters in Neo
RR: 30-60
VC: 5-7
Vt:35
Compliance: 25-50
Resistance: 1-2
Spontaneous Parameters in Adults
RR: 12-20
VC: 65-75
Vt: 4-8
Compliance: 50-170
Resistance: 0.6-2.4
Neonatal Initial Ventilator Settings
PIP
Set to 15-25
Limit should be set to 30
Neonatal Initial Ventilator Settings
Vt
3-5 ml/kg
Neonatal Initial Ventilator Settings
PEEP
3-6 cmH2O
Set to prevent further alveolar collapse
Increases will be made in increments of 1-2 cmH2O
If PEEP reaches 8 then alternative modes should be considered
Neonatal Initial Ventilator Settings
RR
Start at 50
Neonatal Initial Ventilator Settings
Inspiratory Time
0.3-0.4
Start at 0.3
Adjust to reach equibrium
Adult Ventilatory Parameters
PEEP
Start at 5 and aim for optimal PEEP
Increases made in 2-3 increments
Ideal Body Weight Calculation
Male: 50+ 2.3 ( {Height in inches}-60)
Female: 45.5 + 2.3 ( {Height in inches}-60)
Placement of ETT
Below the clavicles
Above carina
~T3 and mid trachea
Neonatal Intubation and Pre-Oxygenating
Pre oxygenate for 20 seconds before intubation
Neonatal Intubation and Suctioning
Suction the mouth before intubation to prevent aspiration
Intubation of the Neonate and Oxygenating
Try to give free flowing oxygen to the neonate durign the intubation attempt without interfering with the intubation
When should you aspiration the stomach of a neonate after a successful intubation
If BMV was required for longer than 2 min before the procedure
International Normalized Ratio
(INR)
Normal: 0.9-1.1
Critical: >6
How to Shape a Breath
Ramp/Rise Time
Will control how quickly the limit is reached
Can affect pt comfort
Will tend to smooth out flow and lower initial peak flow
Tube Compensation
Automatic tube compensation will helps by adding pressure support when weaning
WOB is directly related to size of ETT and MV
Clinicians will enter tube type and internal diameter which will nullifie the resistance imposed on the airway
Will be similar to PS in that an inspiratory pressure is used to compensate for imposed WOB
Different from PS in that TC varies the pressure depening on tube size and inspiratory flow
Tube Compensation on 840
TC
Tube Compensation
Tube Compensation on GE
ARC
Airway Resistance Compensation
Tube Compensation on Hemilton G5
TRC
Tube Resistance Compensation
Tube Compensation on Evita
ATC
Automatic Tube Compensation
How is Tube Compensation Calulated
Ptrachea= Paw-KTube x Flow2
Potential Benefits from Tube Compensation
Increase patient comfort over Pressure Support
Accurately predict readiness for extubation
Reduce risk of air trapping cause by expiratory resistance-Some allow inspiratory and expiratory compensation
Volume Support
Spontaneous Mode that is pressure limited and volume targeted
Flow cycled
Mandatory Minute Ventilation
MMV you set a MV so if the pt is not reaching the MV on their own the the vent will kick in to help
Guarantees a minmum MV even though a pts spontaneous ventilation may change
If the pt maintain MV above set MV then this mode functions like CSV-PS
If the pt MV falls below the set MV only then will mandtory breaths be dleivered
How Mandatory Minute Ventilation Works
A MV is set indirectly via RR and Vt
If the patient breaths above MV than all breaths are pressure support breaths
If the patients MV falls below the set MV then the vent will delvier manadatory breaths at a set Vt to make the total MV
Porportional Assist Ventilation
Used to assit spontaneous ventilation
the breath delivered is similar to PS but the pressure support level delivered is variable and porportional to spontaneous effort
The harder the pt works the more support the vent delivers and vice versa)= POSITIVE FEEDBACK
Porportional Assist Ventilation and E Sensitivity
E Sensitivity set at 27% (27% of inspiratory peak flow)
Pressure support patient trigger pressure limited flow cycles (flow cycle=e sensitivity)
You will never get equilibrium on a pressure support breath
How to manipulate tidal volume with e sensitivity
decrease portional will increase tidal volume and Ti unless the patient is air hungry and try to breath in more at a higher peak volume then it will cut off faster and they will get a lower breath
What will happen to tidal volume if you decrease the resistance in pressure control
Volume will stay the same and Tidy will get shorter
What will happen to tidal volume if you decrease the compliance in pressure control
Decrease TC and Ti dyn and volume will go down
ARDS Net Weaning
Oxygenation
FiO2 <0.40 and PEEP <8 OR
FiO2 <0.5 and PEEP <5
PEEP and FiO2 less than the previous day with spontaneous breathing
ARDS Net Weaning
Other
Systolic BP >90 mmHg w/o vaso pressor
No neuromuscular blockade
ARDS Net ABG Goals
7.30-7.45
All of the following will confirm tracheal ETT placement in neonates except
a. Persistent cyanosis and bradycardia
b. Bilateral breath sounds over the chest
c. Decreasing HR
d. CO2 of 28 on CO2 detector
e. Both A and C
Both A and C
Persistant cyanosis and bradycardia may mean that the ETT is not in the correct placement
Bilateral breath sounds can confirm placement
Decreasing HR can confirm they neonate is getting good respiratory support but is not a confirmation for placement
Even though the CO2 is not that high we are getting a reading which means that it is in the trachea
ARDS Net
How to check Pplat
0.5 seconds inspiratory pause
Should be checked q 4h and after each change in PEEP or Vt
ARDS Net
Pplat > 30 cmH2O
Decrease Vt by 1 ml/kg
Minumum 4 ml/kg
ARDS Net
Pplat <26 cmH2O and Vt <6
Increase Vt by 1 ml/kg until Pplat is >25 cmH2O or Vt 6 ml/kg
ARDS Net
Pplat <30 cmH2O and Breath stacking or dsy-synchrony is occuring
May increase Vt by 1 ml/kg incrememts to 7-8 ml/kg
As long as Pplat remains <30 cmH2O
PaO2/PAO2
Assess WOB and Oxygenation
Normal: 0.75-0.85
Critical: <0.15
ARDS Acidosis Mangement
pH<7.30
Increase RR (max 35)
ARDS <7.15
Increase RR to 35 and if still <7.15 Vt can increase by 1 ml/kg
May give NaHCO3
ARDS Alkalosis Mangement
Decrease RR
ARDS Net Spontaneous Breathing Trial
T-Piece, Trach collar, or CPAP <5 with PS <5
ARDS Net Spontaneous Breathing Trial
Assess for tolerance
SpO2 > 90% and/or PaO2 >60 mmHg
Vt> 4 ml/kg
RR <35
pH>7.3
No respirtory distress
If tolerated for 30 min consider extubation
ARDS Net Spontaneous Breathing Trial
Respiratory Distress
HR >120% baseline
Accessory muscle use
Abdominal paradoxus
Diaphoresus
Dsypnea
AHS Exclusion from Extubation Pathway
Head injury, unstable spinal injury, inotropes and vasopressors, or planned surgery
Head and spinal injuries are relative contraindication and they can still be extubated with dr orders
AHS Spontaneous Trial Readiness
- Resolution of disease
- Adequate oxygenation
- PaO2 >60 mmHg
- P/F > 200
- SpO2 >90%
- PEEP <5
- FiO2 < 0.4
- No uncompensatory respiratory acidosis
- HR <140
- GCS >13
AHS Initiation of SBT
Place pt on PSV of 7 and PEEP of 5 unless there is automatic tube compensation which you put PSV to 0
in first 5 minute monitor tobin score (>105), sweating, anxiety, mental status, SpO2 >90%
If any negative changes occur increase PSV and inform physician
Tobin Score
Also known as rapid shallow breathing index
= (RR)/ (Vt)
An RSBI < 105 breaths/min/L has been widely accepted by healthcare professionals as a criteria for weaning to extubation.
Whereas patients with RSBI > 105 will have a high chance of failure and require re-intubation.
AHS Continue SBT
for pt who are ventilated for <72 hours continue SBT fot 30 min
For pt who are ventilated >72 hours continue SBT 60-120 min
Monitoring should be done first 5 min and the Q15 after
You are ventilating an adult patient in the mode VC-CMV using a decelerating flow waveform. If you switch to a square flow waveform, which of following would occur?
The I:E ratio to increase
.The PIP to increase
The risk of air trapping
Tidal volume to increase
.The PIP to increase
Cord Clamping
Try to delay clamping the cord for at least 60 seconds
If not possible cord milking is a reasonable alternative
European Consensus and Delivery Room Oxygenation
Oxygen for resusucitation should be controlled via a blender
An initial concentration of 30% oxygen is appriopraite of babies <28 GA
For babies that are 28-10 week use an FiO2 of 21-30
European Consensus and Spontaneous Breathing Babies
In spontaneous breathing babies stabilize babies with CPAP at 6 cmH2O via mask or nasal prongs
European Consensus and Plastic Bags
Plastic bags or occlusive wrapping under radient warmer should be used during stabilization in babies <28 weeks
European Consensus Saturation Goals
Saturation goals should be 90-94%
European Consensus
Indications for CPAP
RDS
< 30 weeks gestation when intubation is not needed
European Consensus CPAP Interface
The interface should short binasal prongs or mask with a starting pressure of 6-8cmH20
CPAP pressure should then be individualized based on oxygenation and ventilation
Optimal Mangement for RDS
CPAP with early rescue surfactant should be considered optimal management for babies with RDS
Synchronized NIPPV
Synchronized NIPPV if delivered through a ventilator rather than a bilevel CPAP device can reduce extubation failure, but may not confer long-term advantages such as reduction in BPD
Alternative to CPAP in Weaning
HF may be used as an alternative to CPAP for some babies during weaning phase
Mechanical Ventilation in Neonates European Consensus
Target tidal volume should be used to shorten time on mechanical ventilation
European Consensus and Weaning
When weaning from MV it is reasonable to tolerate a modest degree of hypercarbia provided pH >7.22
Caffeine should be used to facilitate weaning from MV
A short tapering course of low dose dexamethasone should be considered to facilitate extubation in babies who remain on MV after 1-2 weeks
AHS CPAP in Delivery Room
Gestation 25-28 Weeks
Principals
Maintain optimum lung volume and FRC in order to avoid de-recruitment and overdistension
in L&D and acute phase avoid CPAP >6
Infants >28 weeks will be intubated by a senior practitioner
“Early surfactant” does not mean “immediate surfactant”
AHS CPAP in Delivery Room
Gestation 25-28 Weeks
Initial Steps
Clear airway and CPAP at +5
If the baby is not spontaneously breathing or has a HR under 100 begin PPV
If there is mild WOB with SpO2 then maintain CPAP level and move to NICU
If there is more severe WOB or SpO2 is not in range than increase CPAP by 1 and increase FiO2 by 0.10-0.20 to achieve SpO2
If the above did not help consider intubation
NRP Indications for PPV
Apnea
Gasping
HR less than 100
Oxygen saturadtion below target range
