Special perioperative mechanical ventilation modes
1. Special Perioperative Mechanical
Ventilation Modes : HJV,
HFOV, Non-invasive Ventilation
Elizeus Hanindito
Dept. Anesthesiology
Airlangga University – dr. Soetomo General Hospital
2. Non-invasive Mechanical Ventilation
• Delivery of ventilation to the lungs without an
invasive airway (endotracheal or tracheostomy)
• Avoid the adverse effects of intubation or
tracheostomy (early and late)
3. How does NIV work ?
• Reduction in inspiratory muscle work &
avoidance of respiratory muscle fatigue
• Tidal volume is increased
• CPAP counterbalances the inspiratory
threshold work related to intrinsic PEEP.
• NIV improves respiratory system compliance
by reversing microatelectasis of the lung.
4. Advantages of NIV
• Noninvasiveness
– Application (compared with endotracheal
intubation)
a.Easy to implement
b.Easy to remove (allows intermittent application)
– Improves patient comfort
– Reduces the need for sedation
– Oral patency (preserves speech, swallowing, and
cough, reduces the need for nasoenteric tubes)
5. Advantages of NIV
• Avoid the resistive work imposed by the
endotracheal tube
• Avoids the complications of endotracheal
intubation
– Early (local trauma, aspiration)
– Late (injury to the the hypopharynx, larynx, and
trachea, nosocomial infections)
6. Disadvantages of NIV
System
– Slower correction of gas exchange abnormalities
– Increased initial time commitment
– Gastric distension
Mask
– Air leakage
– Transient hypoxemia from accidental removal
– Eye irritation
– Facial skin necrosis –most common complicationL
Lack of airway access & protection
– Aspiration
8. Definition
CPAP : It is a modality of respiratory support in
which increased pulmonary pressure is
provided artificially during the expiratory
phase of the respiration in a spontaneously
breathing neonate.
11. Indications of CPAP
• Respiratory distress : moderate /severe
retraction , nasal flaring , grunting
• Post extubation.
• P aO2 < 60 with FiO2 > 0.6 ( O2 hood).
12. CPAP ranges
Ranges ET Tube Nasal Comment
Low 3—4 4—5 CPAP< 3 not useful
Medium 5—7 6—8 Good range
High 8--10 9--10 Adverse effects
common
Fi O2 controlled from 0.2 to 1.0 with CPAP.
Dr. Gautam Ghosh
13. Guidelines for CPAP
• Start with nasal CPAP of 5—6 cm & FiO2 0.4—0.5
• Increase CPAP by 1 cm if required
• Reach a CPAP of 8—9 cm.
• Now increase FiO2 in small steps of 0.05 up to 0.8
• Clinical /ABG / SpO2 > 30min in each step
• Do not raise FiO2 before pressure : may remove
hypoxic stimulus -- apnea
• Revert to IMV if not responding
14. Optimum CPAP
• Comfortable baby / pink / normal BP
• No retraction / grunt
• No cyanosis / normal CRT
• SpO2 > 90-93 %
• BGA : PaO2 60-80 / PaCO2 40-45 /p H 7.30-7.40.
15. Practical Points in CPAP
• Warm gases at 34—37° C & humidify.
• Gas flow (2.5 x minute ventilation) at 5-8 L/mnt
minimum
• Look for nasal or oral blocks by secretion
• Oro-gastric suction is a must
• Stabilize the head with a cap and string
• Change CPAP circuit/prong every 3 days
• Asepsis
• Sedation (prn)
16. Failure of CPAP
• Retraction / Grunt ++
• Apnea on CPAP
• PaO2 < 50 in FiO2 > 0.8 ( nasal CPAP >8cm)
• PaCO2 > 55
• Baby not tolerating CPAP.
• Commonest cause : delay in starting
17. Weaning from CPAP
• Reduce nasal CPAP to < 8 cm (1 cm decrement)
• Reduce FiO2 by 0.05 to 0.4
• Reach a level of CPAP 4cm / FiO2 0.4
• Remove CPAP and replace a O2 hood.
18. CPAP delivery system
The CPAP delivery system consists of three
components:
• the circuit for continuous flow of inspired
gases.
• the interface connecting the CPAP circuit
to the infant’s airway.
• a method of creating positive pressure in
the CPAP circuit.
25. Types of HFV
• High Frequency Oscillatory Ventilation
• High Frequency Jet Ventilation
• High Frequency Positive Pressure
Ventilation
26. HFOV - General Principles
• A CPAP system with piston displacement of gas
• Active exhalation
• Tidal volume less than anatomic dead space
(1 to 3 ml/kg)
• Rates of 180 – 900 breaths per minute
• Lower peak inspiratory pressures for a given
mean airway pressure as compared to CMV
28. Ventilator Associated Lung Injury
• All forms of positive pressure ventilation (PPV) can
cause ventilator associated lung injury (VALI).
• VALI is the result of a combination of the following
processes:
– Barotrauma
– Volutrauma
– Atelectrauma
– Biotrauma
29. Pressure and Volume Swings
During CMV, there are swings between the zones of
injury from inspiration to expiration.
During HFOV, the entire cycle operates in the ―safe
window‖ and avoids the injury zones.
INJURY
HFOV
CMV
INJURY
30. Gas entering the lungs travels centrally, while gas
leaving the lungs swirls around it
32. Timing CMV HFOV
• Inadequate oxygenation that cannot safely be treated
without potentially toxic ventilator settings and, thus,
increased risk of VALI.
• Objectively defined by:
– Peak inspiratory pressure (PIP) > 30-35 cm H2O
– FiO2 > 0.60 or the inability to wean
– Mean airway pressure (Paw) > 15 cm H2O
– Peak end expiratory pressure (PEEP) > 10 cm H2O
– Oxygenation index > 13-15
34. Initial Frequency Settings
• Guidelines for setting the initial frequency.
Patient Weight Hertz
Preterm Neonates 10 to 15
Term Neonates 8 to 10
Children 6 to 8
Adults 5 to 6
• Adjustments in frequency are made in steps of
½ to 1 Hz.
36. Weaning
• Wean FiO2 for Sat’s > 90%
• When FiO2 60%, wean Paw by 1
• Return to CMV when:
– FiO2 < 40%
– Paw 15-20
– Amplitude < 40
37. HFOV: Conversion
• Pressure limited ventilation
• Delivered tidal volume ~6 ml/kg
• PEEP ~10 cm H2O
• Adjust for Paw same as HFOV
• FiO2 ~40 - 50%
38. Signs of Failure
• OI > 42 at 48 hrs HFOV
• Unable to wean FiO2 > 10% within 24 hours
• Unable to PaCO2 <100 with pH 7.25
Notas do Editor
Interface antara pasien dg respirator tdk menggunakan alat invasif (intubasi,tracheostomy)
Mengurangi WOB & kelelahan , Vt ditingkatkan , membantu tenaga inspirasi berkaitan dg intrinsic PEEP , memperbaiki lung compliance dg membuka microatelectasis.
Jelas menguntungkan dari segi kenyamanan , tdk perlu sedasi/analgesi , mudah dipasang/dilepas.
Tdk ada resistensi spt pd pemasangan pipa ET
Tentu saja efektivitas < invasif , masuk lambung , iritasi wajah/mata/hidung , potensi aspirasi > intubasi.
Tunjangan nafas dimana pasien nafas spontan , tetapi pulmonary airway pressure selalu positif.
Infant flow driver
Initial SettingsAttach the patient circuit to the ventilator and enter the initial settings per the physician’s order. The IPAP setting can be adjusted to achieve the desired CO2 level and tidal volume.In the acute care settings, IPAP setting between 8 to 12 cm H2O are often clinically effective. Pressures above 20 cm H2O usually are not well tolerated and increase the risk of gastric distension and vomiting. Although most patients will swallow some air during noninvasive ventilation, it is usually not a problem unless peak pressure exceeds 20 to 25 cm H2O the gastric opening pressure. In most patients, the placement of a nasogastric tube is not necessary. (36)Typically, start EPAP at 4 cm H2O and increase to meet oxygenation goals. The more hypoxic the patient, the higher the initial EPAP setting. Pressure support equals the difference between IPAP and EPAP, referred to as Delta P. Similar to conventional ventilation, this value affects the volume delivered to the patient. Pressure support is increased by increasing the IPAP setting to achieve desired exhaled tidal volume. On the other hand, overall pressure support is decreased by the same amount EPAP is increased. When adjusting the IPAP or EPAP parameters independently, monitor the patient data for changes in the tidal volume.Next, enter the desired FIO2. A backup rate may be provided in the event the patient becomes apnic. If the backup rate is set to high, it may override the patient’s own effort to initiate a breath. This could trigger the apnea alarm to sound. Consider setting the back up rate to 8. After all the parameters have been entered, the interface can be fitted to the patient.