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 Barotrauma Volutrauma Volutrauma Atlactotrauma Atlactotrauma Biotrauma Biotrauma

NIRS nCPAP Noncycled - noninvasive respiratory support Nasal canula HHHFNC BiPAPCycled-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 hr ventilatations of premature lung 1.Underdeveloped architect. to hold the lung open 2.Thicker and few septa so less SA for gas exchange

nCPAP C V Preterm Lambs at 72 Hours Preterm Lambs at 72 Hours - Distal Airspace Wall Thickness -

CPAP magic Opens the lung at FRC Opens the lung at FRC Keeps it open by minimal constant pressure -least atelecto, baro and volutrauma 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 Pulmonary arterial pressure are least hence less V/Q mismatch – less pressures required No ET tubes- no biotrauma 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 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

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

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 H 2 0 and gradually increased up to 8 cm H 2 0 as required to improve oxygenation and stabilize the chest wall while maintaining ABG :PH>7.25,PCO 2 <60

Fio2 setup < <0.3 FIO 2 Settings for nCPAP – 5 CDP (cm H 2 O)

When CPAP should not be used Persistent or frequent apnea or bradycardia If PCO 2 is high and rising ;PaCO 2 >60 and PH<7.25 Upper airway abnormalities(cleft palate, choanal atresia,tracheoesophagial fistula ) Congenital diaphragmatic hernia

Complications of CPAP Hyperexpansion 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 CPAP trauma 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 CPAP RDS 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 fio % if the neonate has excessive work of breathing PO2 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

جدول شماره 3: تنظیمات فشار و کسر اکسیژن دمی در حمایت تنفسی غیرتهاجمی Settings for SiPAP/B iPAP FiO 2 < >0.5 IPAP cm H 2 O 8910 EPAP cm H 2 O 567

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 :

NIPPV set up (post extubation) PIP: PEEP : 5 – 6 RR : 20 – 30 (same as pre extubation)

NIPPV SET UP(apnea) PIP : PEEP : 4-6 RR : 20 /min

Nasal cannula Low flow nasal cannula.5-2 liter/min o2 Non humidified Moderate flow of 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