NON INVASIVE VENTILATIONArchana R Yashwanth

What is non invasive ventilation?• Modality that supports breathing with out the need for

intubation or surgical airway• Greatest advancement in the management of acute type

2 respiratory failure• Types

Negative pressure ventilationNon invasive positive pressure Continous positive airway pressureBi level positive airway pressure

Why NPPV?• 1.Avoids complication of invasive ventilation• Injury to the teeth , vocal cords, larynx, surgical

complications of tracheostomy tube placements• .infections- VAP , sinusitis• in ability to verbalise, eat , drink and patients comfort • 2. may be administered outside of ICU/ Domestic use

MECHANISM- reduction in inspiratory muscle work , decrease in WOB , decrease in pressure time product(index of muscle oxygen consumption), also by recruitment of alveoli

Goals of NPPV• Short term-1.relieve symptoms2.Reduce WOB3.Improve or stabilise gas exchange4.Optimisepatient comfort5.Good patient ventilator synchorny6.Minimise risk7.Avoid intubations• Long term-1.improve sleep duration and quality 2.Maximise quality of life3.Enchance functonal status4.Prolong survival

Indications and Contraindications

Obstructive sleep apnea syndromeCOPD with exacerbationBilateral pneumoniaAcute congestive heart failure with pulmonary edemaNeuromuscular disorderAcute lung injuryMethod of weaning

Respiratory arrest or unstable cardiorespiratory statusUncooperative patientsInability to protect airwayTrauma or burns involving the faceFacial oesophageal gastric injury ApneaReduced consciousnessAir leak syndromeRelative contraindications• Extreme anxiety• Morbid obesity• Copious secretions• Need for continous ventilatory

assistance• Diseases with air trappng

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ontraindications

TERMS USED IN NPPV

• CPAP- positive airway pressure duting spontanoues breaths

• BiPAP-provides IPAP and EPAP• IPAP-controls peak inspiratory pressure during inspiration• EPAP-controls end expiratory pressure• PEEP-positive airway pressure at end expiratory phase,

used with mechanical breaths• Higher the IPAP , larger tidal volume and

minute ,ventilation• EPAP-same as PEEP, improves oxygenation , increases

FRC,relieves upper airway obstruction

Technique• Anaesthesia• Mild sedation and analgesia

AnxolysisEquipments

• Available ventilators-NPPV/ Conventional ventilatorsNPPV ventilators are cheaper, flexible, portable , good leak

compensation , inspiratory pressureup to 20cm h20.Disadvantage- high flows, single limb rebreathing occurs.

• Ventilator modes- volume limited ventilation,Propotional assist ventilation (senses patients efforts , by tracking inspiratory flow .by adjusting gain on the flow and volume signals , operator is able to select propotion of breathing work to be assisted.

• Positioning• Face mask or nasal mask application (interfaces)• 30 to 90 degrees upright position• Nasal mask fits just above the junction of nasal bone&

cartilage• Velcro straps

Interfaces• Nasal prong application• Fill the nasal openings with out stretching the skin or

undue pressure on the nares• No lateral pressure on the septum

• Pressure range of 3 to 20 cm H20

• Significant leak from mouth

• Advantage- comfort and patience compliance

• Disadvantage-gasleak , nasal dryness or dicharge

Nasal pillows Face Mask

• Tight seal’• Advantage-good seal• Disadvantages

• Potential dangers of regurgitation and aspiration

• Patient non compliance• Regurgitation and

aspiration• Asphyxation • Alarm and monitor is

necessary

Troubleshooting with interfaces1.Air leaks

2.Pressure points, sore or dry eyes

3.Nasal congestion or discharge

4.Nasal airway drying

5.Skin break down irritation-

6.Sensitive front teeth

7.Head gear problem

Adjust head gear Try chin strap Try spacers or foam pads Try diff. mask

Adjust head gear Change spacers or foam pads Try different mask

Adjust positive pressure setting Add filter Add humidity

Increased fluid intake Increase room humidity Try nasal saline or water based lubricant

Adjust or try another head gear Use spacers, foam pad Resize mask Change to diff cleaning solution

Adjust head gear

Try smaller or differentmask Try disposible head gear Try larger head gear

Machine setup

Humdifier-with 1 L bag of

water,adequarte .umidity prevents drying of

secretions

Oxygen flow-6-10/l min, washes out

carbondioxide, compensates leak , generates adequate

pressure

Occlude the pressure line connection port with the white plug provided

For CPAP , default pressure is 4-6 cm H20PRESSURE UP TO 10 CM H20 CAN BE USED

Check water level and adjust for evaporation

BIPAP(pressure limited ventilation)IPAP-15cm H20-Controls peak inspiratory pressure during inspiration

EPAP-5CMH20-controls end expiratory pressure , PEEP when IPAP>EPAP

Provides IPAP and EPAP

CPAP when IPAP=EPAP

Pre determined inspiratory pressure is delivered

This causes different tidal volumes, depending on the resistance of the respiratory system.

Leak compensation

3 modes• Pressure support- set pressure during inspiration• Pressure control-set number of breaths per minute at set

pressure• Bilevel positive airway pressure –delivers different

pressures during inspiration and expiration

• Main indications – acute respiratory failure• COPD Exacerbation• Not improving on CPAP- provides increased airway pressue during expiration

, but it may add inspiratory assistance, there by reducing WOB

CPAP (1/3)

Continuous positive airway pressure during the spontaneous breath

Leads to increase FRC aboce closing capacity

Leads to opening of collapsed alveoli , decreased intrapulmonary shunting , improving oxygenation and lung compliance

Decrease WOB

Provision of an adequate air flow rate

Its treatment of choice in OSA without significant carbon-dioxide retention

OSA- diagnosed by nocturnal polysomnography and severity determined by apnea and desaturation index

CPAP (2/3)• Avg. no. of apnea in each hour of sleep during

the testApnea –

hypoapnea indxex

• Avg. number of oxygen desaturation of 4% or more from baseline

Desaturation index-

• H/o snoring, obesity ,increased neck circumference, hypertension and family historyRisk factors

• Oral applications prosthetic mandibular advancementTreatment

• Tonsillectomy and uvulopalaopharyngoplasy Surgical

CPAP (3/3)

• Auto titration • RAMP-gradually increases pressure • C-FLEX-provides pressure relief during exhalation • Provided breath to breath basis

After setting CPAP – pulse oximerty and no of apnea epsodes in polysomnography are used to fine tune CPAP level

Monitoring• ABG• RR• Heart rate• Continuous ECG recording during first 12 hrs• Repeat ABGS- 1 hr after intiation of NIV/ change of settings , after 4

hrs hrs in clinicaly non improving patients• In acutely ill patients

• Every 15 mins in first hour • Every 30 mins in 1 to 4 hr period• Hourly in 4 to 12 hour period

• Level of consciousness • Patient comfort• Chest wall movement, ventilator synchorny and accessory muscle

use

Weaning • Based on clinical improvement and stability of patients

condition• Studies show RR<24/MIN• HR-<110/MIN• Compensated Ph->7.5• Spo2->90% on fio2 <4l/min

Predictors of success in NPPV• Young age• Low acuity of illness• Able to cooperate• Able to coordinate breathing with ventilator• Less air leaking , intact dentition• Hypercarbia >45 but <92 mmhg • Acidemia7.1-7.35• Improvement of HR, RR and gas exchange with in first

one hour

Criteria for failure of NNPV• MAJOR1.Respiratory arrest2.LOC3.Psychomotor agitation requiring sedation4.Hemodynamic instabiltiyHR<50/min with loss of alertness

• MINOR1.RR>35/MIN and higher than as recorded on admission2.Arterial Ph-<7.3Pao2<45 despite oxygen supplementationPresence of weak cough Presence of one major criterion is an indication of immediate intubation Presence of 2 minor criteia after 1 hr of treatment is considered an indication

of intubation

complications• 1.monitoring • 2.decreased clerance of secretions , when seal must be

mintained• 3. caution when given to patients who have one side

affected lung• 4. due to air seal- ulceration and pressure necrosis, eye

irritation• 5.distension of stomach due to aerphagia, aspiration • 6.preload reduction and hypotension

Refernces• Clinical application of mechancal ventilation – 3rd edition –

David W.Chang • RACE 2011- mechanical ventilation- JV Divatia AS

Arunkumar k thamaraiselvi,MK Renuka , JA Roche

• Non invasive ventilation- Dr. T. R. Chandrasekhar. • Millers 7th edition

THANK YOU