non invasive ventilation dr sadeghimoghadam niv non invasive ventilation is the delivery of...

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