non invasive ventilation dr sadeghimoghadam niv non invasive ventilation is the delivery of...
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non invasive ventilation Dr
sadeghimoghadam
NIV
Non invasive ventilation is the delivery of respiratory support without the need for intubation
Ventilator induced lung injury
Barotrauma VolutraumaAtlactotraumaBiotrauma
NIRS
nCPAP Noncycled - noninvasive respiratory support
Nasal canula
HHHFNC
BiPAP Cycled-noninvasive respiratory support
SiPAP
NIPPV
Physiological Considerations for Neonates
Preferential nose breathers Flow and pressure in the airway can stimulate
breathing Predisposed to alveolar collapse at end
exhalation Chest wall compliance is generally greater
than lung compliance Tend to use abdominal breathing
Why lung of premature neonate has tendency to atelectasis?
They are not strong enough to expand surfactant- deficient ,fluid filled lungs
Immature lung with underdeveloped structures to maintain lung volume
Their chest wall is very compliant and retract with each inspiration
The pharynx is not well stabilized and is more likely to collapse
Why lung of premature neonate has tendency to atelectasis?
The round shape of chest wall and horizontal ribs reduces the potential for lung expansion
Diaphragm is relatively flat and less effective
Loss of intercostal muscle activity during REM sleep
PDA may increase fluid in the lung making them less compliant
Continuous Positive Airway Pressure
Definition
Maintenance of an increased (positive) trans-pulmonary pressure during the
inspiratory & expiratory phase of respiration, with the patient breathing
spontaneously.
Clinical Uses in the NICU
A bridge between intubation/mechanical ventilation and supplemental oxygen administration
How CPAP improves respiratory function?
Reduces the chance of upper airway occlusion and its resistance by mechanically splinting it
Alters the shape of diaphragm and increases its activity
Improves lung compliance and decrease air way resistance
How CPAP improves respiratory function?
Enables a greater TV for a given negative pressure with reduction in work of breathing
Conserves surfactant on the alveolar surface
Effect of Ventilator on Preterm Lamb Lung
No ventilation
24 hrventilatations of premature lung
1.Underdeveloped architect. to hold
the lung open
2.Thicker and few septa so less SA
for gas exchange
nCPAPC V
Preterm Lambs at 72 Hours- Distal Airspace Wall Thickness-
CPAP magic
Opens the lung at FRC Keeps it open by minimal constant pressure -least atelecto, baro and volutrauma Pulmonary arterial pressure are least hence less V/Q mismatch – less pressures required No ET tubes- no biotrauma
Indications for use of CPAP
Treatment of RDS in premature neonates
Postextubation management of premature neonates
Apnea of prematurity
Other indications for use of CPAP
TTN Pneumonia Aspiration syndroms CHF PDA Laryngo,broncho and or tracheomalacia Postop respiratory management of
certain patients
Components of CPAP
Gas source Pressure generator Patient interface
TECHNIQUES FOR PRESSURE GENERATION
Expiratory flow valve (e.g. ventilator) Underwater tube 'bubble' CPAP (underwater
expiratory resistance) Benveniste device (pressure generation at
nasal level: gas jet device connected to nasal prong/s)
Infant Flow Driver (IFD) system (pressure generation in Infant Flow 'Generator' at nasal level
Continuous flow CPAP
Vary the CPAP pressure by a mechanism other than flow variation
1- infant ventilator / stand alone CPAP machine pressure is generated by exhalation valve and adjusted by changing the expiratory orifice size
Ventilator CPAP
No need of a separate equipment Can easily switched over to mechanical
ventilation if CPAP fails Standard flow of 5-8 liter/min may be
insufficient in the presence of high leak
Continuous flow CPAP
Bubble CPAP
Pressure is generated by submerging the expiratory limb in to water chamber and adjusted by altering its depth
Bubble CPAP
A fluid-filled reservoir is used as a means of maintaining the desired level of CPAP
Oscillations in the circuit have been speculated to aid in ventilation
Simple, inexpensive Can identify large leaks at the nares
(bubbling stops)
Bubble CPAP
Absence of electronic display of pressure and fio2
Flow has to be altered to ensured proper bubbling
It is difficult to detect high flow which can lead to over distension of lungs
Why Won’t It Bubble?
Complete or partial circuit disconnect Complete or partial prong disconnect The prongs are out of the nares Inadequate flow through the circuit Prongs are too small for the patient Patient’s mouth is open
Variable flow CPAP
The desired CPAP level is generated by varying the flow
Infant flow driver Viasys SiPAP Benveniste device
Variable flow devices
Maintain more uniform pressure Might decrease work of breathing Recruits lung volume more effectively
Variable flow CPAP mechanism
Patient interface CPAP delivery
Nasal prong (short:6-15mm) or ( long40-
90mm :nasopharyngial prong) Single or binasal eg : argyle ,hudson or IFD prong
Nasal interfaces
Nasal prong
Nasal prong
Simple , lower resistance ,mouth leak act as a pop off mechanism
Difficult to fix Risk of trauma to nasal septum or
turbinate Due to mouth leak end expiratory
pressure may be variable Is better than nasopharyngial prong
Nasopharyngeal prong
Nasopharyngial prong
Easy availability and economical More secure fixation More easily blocked by secretions and
kinked
Nasal mask
Nasal mask
Minimal nasal trauma Difficulty in obtaining a tight seal May be useful when the infant nares is
too small to accept nasal prong
Face mask , face chamber ,head chamber
May produce severe gastric distention or gastric rapture
Trauma to facial skin or eyes Increased risk of ICH CO2 retention from increased dead
space CPAP is seldom applied today with this
devices
Endotracheal CPAP
Increase work of breathing CO2 retention
Clinical Application
The correct size nasal prongs will be those which completely fill the lumen of the nares without stretching them.
Too small of prongs will necessitate the need for an increased flow setting which leads to internal swelling of the nasal passages
Too large of prongs will lead to pressure sores and necrosis
ways to determine the appropriate level of CPAP
CXR :the lung is well inflate or over expand
Chest exam :retraction , tachypnea or grunting means that higher pressure is likely to be needed
If oxygenation is the main problem, it will probably improve if the pressure is increased
ways to determine the appropriate level of CPAP
If CO2 retention is the main problem , consider reducing the pressure
Start CPAP at 4-5 cm H20 and gradually increased up to 8 cm H20 as required to improve oxygenation and stabilize the chest wall while maintaining ABG :PH>7.25 ,PCO2 <60
Fio2 setup
<0.5 0.3-0.5 <0.3 FIO2Settings for nCPAP
7- 8 6 4 – 5 CDP (cm H2O)
When CPAP should not be used
Persistent or frequent apnea or bradycardia
If PCO2 is high and rising ;PaCO2 >60 and PH<7.25
Upper airway abnormalities(cleft palate , choanal atresia ,tracheoesophagial fistula )
Congenital diaphragmatic hernia
Complications of CPAPHyperexpansion of lung
clinically leads to hypoxemia and hypercarbia Air leak syndrome Increased work of breathing Increased PVR Impaired venous return and CO Decrease GFR and urine output Increased ICP
GI Complications of CPAP
GI distention :CPAP belly syndrome Gastric perforation Decrease bowel perfusion and
increased risk of NEC
Complications of CPAPtrauma to nose and skin
Nasal irritation , damage to the septum, mucosal damage and possibly sepsis
Skin irritation , necrosis or infection of face from the fixation devices
Nursing care
Suction of secretions prevention of leakage by proper fixation
of prongs or mask and closing the infants mouth
Prevention of nasal septum or mucosal damage
Facial Skin care Mouth wash by normal saline
Nursing care
GI decompression by OG tube Change of position every 2-4 hours Sedation?
Weaning from CPAP
If there is not evidence of apnea bradycardia or increase work of breathing
Decrease fio2 gradually to 40% or less Then gradually decrease pressure to 4
cmH2O If patient tolerates , D/C the CPAP
Signs of CPAP failure
Continuity of grunting or retraction Persistence of apnea With fio2 >80% and CPAP pressure of 8
cmH20 , O2sat<85% PCO2>55 Severe irritability and intolerance of
nasal prongs
Common causes of CPAP failure
Inadequate flow Inadequate CPAP pressure Improper size of nasal prong or bad
fixation Obstruction of prongs due to secretions Opening of mouth
If CPAP therapy was successful
There is no retraction or grunting Patient is not irritable O2SAT is 85-92% CRT 3 sec or less Pao2 :50-70 , pc02 :40-55
Clinical use of CPAPRDS
Use of CPAP associated with a lower rate of failed treatment
(death or use of assisted ventilation) with an increased rate of pneumothorax
(cochrane review 2012)
In preterm infant with RDS application of CPAP is associated with reduced respiratory failure and mortality
CPAP should be used in all preterm infant with RDS unless there is a contraindication to its use
Prophylactic CPAP did not show any significant benefit in the rate of death ,BPD ,IVH, subsequent need for intubation
Current evidence does not support the use of prophylactic CPAP
Early versus late CPAP
Early CPAP conserves the neonates own surfactant stores and minimizes the stimulation of inflammatory cascade
Early CPAP reduces the need for : surfactant mechanical ventilation fewer days of intubation
Early CPAP
Fio2 requirement of equal or greater than 30%
Down or silverman RDS score >3
Optimal pressure & fio2
A pressure of 5 cm H2O is a good starting point & can be increased in increments of 1-2 up to a MAX of 8 cm H20
Start with fio2 50%(titrate based on spo2) increase in steps of 5% if spo2<88% up to MAX 80%
Failure of CPAP
Even on a CPAP of 7-8cm H20 and fio2 70-80% if the neonate has excessive work of breathing PO2 < 50 mmHg PCO2 > 60 PH < 7.2 Recurrent apnea
Apnea of prematurity
CPAP is used when clinically significant episodes of apnea persist despite optimal methylxanthine therapy
NIPPV is probably more effective than NCPAP
Apnea of prematurity
Start at 4 increase up to 5 cmH20 Fio2 : 21 – 40 % (as decided by spo2)
further increase is not helpful CPAP failure : recurrent episodes of
apnea requires PPV
Post extubation
CPAP reduces the incidence of extubation failure in preterm WLBW infants
Start at pressure of 4-5 cm H2O increase in steps of 1-2 cm H20 up to MAX 7-8 cm
Start with fio2 5-10% above preextubation up to MAX 80%
CPAP failure : same as RDS
BiPAP or SiPAP
: تنظیمات فشار و کسر 3جدول شماره اکسیژن دمی در حمایت تنفسی غیرتهاجمی
Settings
for SiPAP/BiPAP
FiO2 <0.3 0.3-0.5 >0.5
IPAP cm H2O
8 9 10
EPAP cm H2O
5 6 7
Nasal intermittent positive pressure ventilation(NIPPV)
Can be synchronized( sNIPPV ) Is a form of respiratory assistance that
provides more respiratory support than CPAP
May prevents intubation in larger fraction of neonates
NIPPV
Maintains higher MAP than CPAP Provides greater ability to recruit
collapsed alveoli's and improves oxygenation
Can provides sigh breath
sNIPPV
Reduces thortoacoabdominal asynchrony , respiratory rate and work of breathing
Provides more discomfort and agitation due to production of higher flow in the pharynx
NIPPV
Nasal airway interfaces and fixation techniques are similar to CPAP
Ventilator modes: IMV is usual mode NIMV or SNIMV Clinical data for efficacy of nasal
pressure support ventilation is not enough
NIPPV set up(RDS)
.PIP:22 PEEP:6-8 RR:50/min IT : 0.3 - 0.5
NIPPV set up (post extubation)
PIP:16 - 18 PEEP : 5 – 6 RR : 20 – 30 (same as pre extubation)
NIPPV SET UP(apnea)
PIP : 10 - 12 PEEP : 4-6 RR : 20 /min
Nasal cannula
Low flow nasal cannula .5-2 liter/min o2 Non humidified Moderate flow of 1.5-2 l/m can produce
pressure of 6-10 cm H2O
Humidified high flow nasal cannula
Decrease dead space Produce continuous positive pressure Its use is easier and less invasive than
NCPAP The baby is more accessible for KMC
HHFNC
Required flow :
Flow = .92 +(.68 ×wt)
Produced pressure
P cmH2O = .7 +(1.1 ×flow ÷ wt )
Clinical application of HHFNC
Component : blender ,patient circuit ,(triple lumen cartridge that highly humidify oxygen),nasal cannula
HHFNC
disadvantage : The amount of produced pressure is
unregulated and unpredictable Commercial devices : vapotherm ,fisher
&pykle
HHFNC
Indications for use : In treatment of RDS (as CPAP) Post extubation Treatment of apnea
More study must be done before recommendation for routine use
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