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 ventilation

Non invasive positive pressure

Continous positive airway pressure

Bi 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 symptoms

2.Reduce WOB

3.Improve or stabilise gas exchange

4.Optimisepatient comfort

5.Good patient ventilator synchorny

6.Minimise risk

7.Avoid intubations

• Long term-1.improve sleep duration and quality

2.Maximise quality of life

3.Enchance functonal status

4.Prolong survival

Indications and Contraindications

Obstructive sleep apneasyndrome

COPD with exacerbation

Bilateral pneumonia

Acute congestive heart failure with pulmonary edema

Neuromuscular disorder

Acute lung injury

Method of weaning

Respiratory arrest or unstable cardiorespiratory status

Uncooperative patients

Inability to protect airway

Trauma or burns involving the face

Facial oesophageal gastric injury

Apnea

Reduced consciousness

Air leak syndrome

Relative contraindications

• Extreme anxiety

• Morbid obesity

• Copious secretions

• Need for continous ventilatoryassistance

• Diseases with air trappng

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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 analgesiaAnxolysis

Equipments

• Available ventilators-NPPV/ Conventional ventilators

NPPV 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 H20

PRESSURE UP TO 10 CM H20 CAN BE USED

For BIPAP-IPAP-15CMH20,EPAP 5 CM H20

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

Reduces left ventricular transmural pressure, there fore increasing CO, pressures limited to 5-15cm H20

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 test

Apnea –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 uvulopalaopharyngoplasySurgical

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

• MAJOR

1.Respiratory arrest

2.LOC

3.Psychomotor agitation requiring sedation

4.Hemodynamic instabiltiy

HR<50/min with loss of alertness

• MINOR

1.RR>35/MIN and higher than as recorded on admission

2.Arterial Ph-<7.3

Pao2<45 despite oxygen supplementation

Presence 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