““Bi-Level and Non-invasive Bi-Level and Non-invasive Intermittent Postive Pressure Intermittent Postive Pressure

VentilationVentilation”.”.

M.A . KingM.A . KingRespiratory Support & Sleep Respiratory Support & Sleep

Centre,Centre,Papworth Hospital, Cambridge,Papworth Hospital, Cambridge,

CB3 8RE, UK CB3 8RE, UK

Bi-level and NIPPVBi-level and NIPPV Volumetric mechanical ventilation Volumetric mechanical ventilation

is usually reserved for the is usually reserved for the unconscious patient and is unconscious patient and is delivered by an endotracheal tube.delivered by an endotracheal tube.

Non-invasive Intermittent Positive Non-invasive Intermittent Positive Pressure Ventilation is delivered by Pressure Ventilation is delivered by a mask. a mask.

Bi-level and NIPPVBi-level and NIPPV

PlanPlan

Avoid mentioning CPAP and Bi-Level in OSA !Avoid mentioning CPAP and Bi-Level in OSA ! Focus in non-invasive ventilatory support.Focus in non-invasive ventilatory support. What is ventilatory failure?What is ventilatory failure? Who needs this treatment?Who needs this treatment? What do the machines do?What do the machines do? What are the outcomes?What are the outcomes? DiscusionDiscusion : : Do Sleep Technologists need to be involved Do Sleep Technologists need to be involved

in these treatments?in these treatments?

Technological developments since the Technological developments since the invention of CPAPinvention of CPAP

OSA

CPAP

OSA with lung problems

Bi-Level

Ventilatory insufficiency

Ventilatory Failure

Bi-Level Bi-Level

Pressure support ventilators

Pressure support ventilators

1987 1990 1995

<1987

2000 <1987

Ventilatory Failure.Ventilatory Failure.Lung Function = Ventilation and gas exchangeLung Function = Ventilation and gas exchange

Minute Ventilation is a function of Minute Ventilation is a function of respiratory respiratory raterate and tidal volumeand tidal volume

Ventilatory FailureVentilatory Failure causes a rise in CO2 and causes a rise in CO2 and drop in O2drop in O2

Gas Exchange (respiratory) failure causes Gas Exchange (respiratory) failure causes hypoxia alonehypoxia alone

““Pump” FailurePump” Failure..

Respiratory control centres.Respiratory control centres. Neurological system ( Nerves and Neurological system ( Nerves and

synapses)synapses) MuscleMuscle Mechanics ( Thoracic cage).Mechanics ( Thoracic cage).

RESTRICTIVE VENTILATORY DEFECTRESTRICTIVE VENTILATORY DEFECT

Restrictive defect.Restrictive defect.

Small lungs in a Small lungs in a rigid chest cage.rigid chest cage.

Normal lungs which Normal lungs which can not be can not be expanded.expanded.

Lung mechanics Lung mechanics are altered and are altered and efficiencey lost. efficiencey lost.

Ventilatory Pump.Ventilatory Pump.

Cerebral cortex

Brainstem

Respiratory muscles

Ventilation

Airflow resistanceRestrictive lung defect.Chemoreceptors

Mechanoreceptors

WAKE

Sleep-wake

Minute ventilation = MV

Respiratory Muscle Respiratory Muscle WeaknessWeakness

Begin AJRCCM 1997 156 133-139

MV reduced

TV

RR

Control

work

Hypercapnoea

Hypoxia (hypersomnia)

Prolonged hypoventilation + or – events (AHI), Desats, Arousals, WASO, poor sleep architecture.

Acidosis

Ventilatory Failure

Muscle fatigue

Progressive and insidious

pump

MV reduced

TV

RR

Control

work

Hypercapnoea

Hypoxia

Prolonged hypoventilation + or – events (AHI), Desats, Arousals, WASO, poor sleep architecture.

Acidosis

Ventilatory Failure

Neuro-Muscle insult

Acute

CVA

Trauma

Neuro’ disease

Infection

Obesity epidemic hits Europe (not Obesity epidemic hits Europe (not France).France).

Nocturnal ventilatory Nocturnal ventilatory insufficiencyinsufficiency

Reduced tidal volume and reduced Reduced tidal volume and reduced frequency.frequency.

Reduced minute volume = Reduced minute volume = hypercapnoea and hypoxia.hypercapnoea and hypoxia.

Indications for NIPPV.Indications for NIPPV.

Ventilatory pump failure.Ventilatory pump failure. Chronic or acute.Chronic or acute. Reduced MV, hypoxia with Reduced MV, hypoxia with

hypercapnoea.hypercapnoea.

( potential for normal gas exchange – ( potential for normal gas exchange – single system failure). single system failure).

Assessment.Assessment.

Arterial blood gases (ABGs).Arterial blood gases (ABGs). Overnight oximetry and CO2Overnight oximetry and CO2 Lung Function.( volumes and muscle Lung Function.( volumes and muscle

strength)strength) Medical exam ( cardio-vascular)Medical exam ( cardio-vascular) AHI and sleep stages have little AHI and sleep stages have little

diagnostic or prognostic valuediagnostic or prognostic value..

Simple overnight oximetry.Simple overnight oximetry.

What do the machines do?What do the machines do?

Non-invasive ventilation- Non-invasive ventilation- objectivesobjectives

1.1. Improve alveolar ventilation & Improve alveolar ventilation & oxygenation.oxygenation.

2.2. Reduction of work of breathing.Reduction of work of breathing.

3.3. Airway support.Airway support.

Objective:Improve alveolar Objective:Improve alveolar ventilation & oxygenation.ventilation & oxygenation.

The physiological mechanism is The physiological mechanism is complex & dependent upon the complex & dependent upon the pathology/disease mechanism.pathology/disease mechanism.

1.1. paO2=[(Pb-SWVP)xpaO2=[(Pb-SWVP)xFiO2FiO2]-PaCO2/RQ]-PaCO2/RQ

2.2. Increased Increased Tidal volumeTidal volume and and raterate = = minute Ventilation.minute Ventilation.

Work of breathingWork of breathing

Work increases when FRC reduced or when TV = VC

Work of breathingWork of breathingWhen FRC and lung compliance are reduced more work is required to inflate the lung. By applying PEEP, the lung volume at the end of exhalation is increased. The already partially inflated lung requires less pressure and energy than before for full inflation

TV

FiO2 & improved MV ( TV & RR)FiO2 & improved MV ( TV & RR)

TV

RR

Ti

Te

FiO2

rco

Mechanical Ventilatory Mechanical Ventilatory SupportSupport

Invasive – endo-tracheal tube.Invasive – endo-tracheal tube.

Non- invasive ventilationNon- invasive ventilation (NIV). (NIV). Negative Pressure NIVNegative Pressure NIV Positive Pressure NIV *Positive Pressure NIV *

Negative Pressure NIV precedes Negative Pressure NIV precedes positive pressure ventilation by 100 positive pressure ventilation by 100

years.years. - - Patient lays inside a rigid cylinder with neck and Patient lays inside a rigid cylinder with neck and

head outside cylinder.head outside cylinder. A vacuum pump creates a negative pressure A vacuum pump creates a negative pressure

within the chamber (outside of chest)within the chamber (outside of chest) - this causes expansion of the patient's chest. This - this causes expansion of the patient's chest. This

change in chest geometry reduces intrapulmonary change in chest geometry reduces intrapulmonary pressure and ambient air flows into the lungs. pressure and ambient air flows into the lungs.

When the vacuum ends, the negative pressure When the vacuum ends, the negative pressure applied to the chest drops to zero, and the elastic applied to the chest drops to zero, and the elastic recoil of the chest and lungs results in passive recoil of the chest and lungs results in passive exhalation. exhalation.

Pump – Adjustable rate and adjustable negative Pump – Adjustable rate and adjustable negative pressure.pressure.

Iron lung.Iron lung.

Limitations of Negative Limitations of Negative Pressure NIVPressure NIV

Unsupported upper airway- Unsupported upper airway- obstruction induced with high obstruction induced with high transluminal pressure gradients.transluminal pressure gradients.

Can reduce cardiac OP and Can reduce cardiac OP and peripheral oedema.peripheral oedema.

CONTROLLED ventilation.CONTROLLED ventilation. Limited technologies.Limited technologies.

Positive Positive PressurePressure NIV NIV

1. Delivery of positive pressure to lungs1. Delivery of positive pressure to lungs

without intubationwithout intubation..

2. Delivery of air is 2. Delivery of air is patient controlledpatient controlled (with machine back up delivery).(with machine back up delivery).

3. Air is delivered 3. Air is delivered via a nasal maskvia a nasal mask or or oro-naso mask ( full face mask).oro-naso mask ( full face mask).

NIPPVNIPPV

Nomenclature of Positive pressure systemsNomenclature of Positive pressure systems CPAPCPAP Bi-levelBi-level NIPPVNIPPV IPAPIPAP EPAPEPAP PEEPPEEP Ventilating – peak pressure (Ventilating – peak pressure (pressure pressure

support)support) Triggers - CyclingTriggers - Cycling Ti. Te, I/E ratioTi. Te, I/E ratio Mode S, ST, TMode S, ST, T Rise TimeRise Time RampsRamps

FiO2, tidal volume & rate.FiO2, tidal volume & rate.

FiO2 – FiO2 – room air 20.8%, facility to add room air 20.8%, facility to add oxygen. O2 % not measured. oxygen. O2 % not measured.

TVTV – – Patient controlled breath enhanced Patient controlled breath enhanced by delivery of air to a targetby delivery of air to a target pressure pressure level. level. Missed breaths recognised.Missed breaths recognised.

RR- RR- apnoea apnoea recognised. recognised. Back up rateBack up rate.. delivered. delivered. Tachypnea Tachypnea reduced by reduced by controlcontrol of of inspiratory time inspiratory time andand expiratory time.expiratory time.

Improved alveolar ventilation & Improved alveolar ventilation & oxygenation.oxygenation.

The physiological mechanism is The physiological mechanism is dependent upon the dependent upon the pathology/disease mechanism.pathology/disease mechanism.

paO2=[(Pb-SWVP)xpaO2=[(Pb-SWVP)xFiO2FiO2]-PaCO2/RQ]-PaCO2/RQ Increased Increased Tidal volumeTidal volume and and raterate = =

minute Ventilation.minute Ventilation.

Basic summaryBasic summary Trigger levelTrigger level= spontaneous patient effort to = spontaneous patient effort to

trigger a machine “breath”.trigger a machine “breath”. IPAPIPAP = expands the lungs more. = expands the lungs more. EPAPEPAP = supports small airways and allows = supports small airways and allows

for PEEP.for PEEP. PEEPPEEP= increases the volume held in the = increases the volume held in the

lungs after passive recoil. Holds open alveoli lungs after passive recoil. Holds open alveoli & improves gas exchange.Reduces work.& improves gas exchange.Reduces work.

T or back up rate-T or back up rate- ensures machine breaths ensures machine breaths if the patient does not trigger.if the patient does not trigger.Status/progress measured with CO2 & O2 Status/progress measured with CO2 & O2

measurementsmeasurements

FiO2 & improved MV ( TV & RR)FiO2 & improved MV ( TV & RR)

TV

RR

Ti

Te

FiO2

rco

Bi-levelBi-level

Technology has developed from CPAP over Technology has developed from CPAP over several years.several years.

Splints upper airway.Splints upper airway. Supplements Spontaneous breathing, Supplements Spontaneous breathing,

synchronisation, synchronisation, improves comfortimproves comfort.. Reduces work of breathing.Reduces work of breathing. Time. Missed breaths delivered.Time. Missed breaths delivered. Range of features and settings added in Range of features and settings added in

recent times. Alarms – essentially a recent times. Alarms – essentially a ventilator.NIPPVventilator.NIPPV

Unrecognised ventilatory Unrecognised ventilatory insufficiency leads to big insufficiency leads to big

problemsproblems

Problems with Home nocturnal Problems with Home nocturnal NIVNIV

Cost of ventilator.Cost of ventilator. Choice of ventilator- locked settings.Choice of ventilator- locked settings. Mask problems.Mask problems. Compliance ( nights and hrs used)Compliance ( nights and hrs used) Need to monitor efficacy and share Need to monitor efficacy and share

medical care with local doctor.medical care with local doctor. Rare diseases, physical disability, Rare diseases, physical disability,

mental disability, agitation, poor sleep.mental disability, agitation, poor sleep.

Clinical Outcomes & Clinical Outcomes & observational studies.observational studies.

PhysiologyPhysiology – ABGs, TcCO2, SpO2. – ABGs, TcCO2, SpO2.

Lung Function.Lung Function.

Psg – AHI little value. WASO and better Psg – AHI little value. WASO and better sleep.sleep.

Quality of LifeQuality of Life – Activities of Living. – Activities of Living.

Health care utilityHealth care utility (cost) (cost)

SurvivalSurvival

Post NIV

Mean overnight oximetry before and after NIVMean overnight oximetry before and after NIV

elective Post exacerbation

Mode of Referral

70.0

75.0

80.0

85.0

90.0

95.0

100.0 Sleep Study

Baseline

Mean O2

Discharge

Mean O2

NIV : Wake ABGs in Myotonic NIV : Wake ABGs in Myotonic Dystrophy Dystrophy

Nugent Chest 2002 121 459-464

Numerous publications: NIV in Numerous publications: NIV in Restrictive lung and neuromuscular Restrictive lung and neuromuscular

diseasedisease

No prospective randomised No prospective randomised controlled trialscontrolled trials

Multiple case series and 2 Multiple case series and 2 withdrawal trials all showing similar withdrawal trials all showing similar treatment effectstreatment effects

Should NIV be used in Should NIV be used in COPDCOPD??

UK: 30,000 COPD deaths each year

· By 2020 COPD is predicted to be the third biggest killer in the world and will be responsible for the deaths of over six million people

· COPD is a major cause of medical admissions, particular in winter. 308,355 emergency hospital admissions per year.

· Of those that are admitted to hospital for COPD, 1 in 10 will die in hospital, one in three will die within six months, and 43% will die within twelve months of their admission to hospital

·

600,000 patients diagnosed with COPD in the UK

Cochrane Systematic Review Nocturnal NIPPV for at least 3 months in hypercapnic patients with stable COPD had no consistent clinically or statistically significant effect on lung function, gas exchange, respiratory muscle strength, sleep efficiency or exercise tolerance.The small sample sizes of these studies precludes a definite conclusion regarding the effects of NIPPV in COPD.

More evidence is required.

SummarySummary Bi Level is needed for some OSA patients.Bi Level is needed for some OSA patients. Bi-Level machines have some features of Bi-Level machines have some features of

pressure support ventilators but may not be pressure support ventilators but may not be appropriate for all patients.appropriate for all patients.

Ventilatory Failure is common in some Ventilatory Failure is common in some diseases.diseases.

Long term NIV is more effective for some Long term NIV is more effective for some patient groups than others.patient groups than others.

Potential for Potential for dramatic increasedramatic increase of Obesity of Obesity Hypopnoea Syndrome across Europe.Hypopnoea Syndrome across Europe.

Should Psg technologists be Should Psg technologists be involved in NIV services?involved in NIV services?

Nocturnal (sleep related) Ventilatory Nocturnal (sleep related) Ventilatory insufficiency.insufficiency.

Diagnostics. (type of abnormality)Diagnostics. (type of abnormality) Ventilatory Failure is not determined Ventilatory Failure is not determined

by events (AHI)by events (AHI) Treatment – medical speciality.Treatment – medical speciality. Outcomes. (efficacy of NIV) Outcomes. (efficacy of NIV)

Is our speciality led by Is our speciality led by technologies ?technologies ?

CPAP

(OSA is one of 87 sleep disorders)

Ventilatory Failure

Bi-level machines

?

Equipment by disorder ( few patients with OSA Equipment by disorder ( few patients with OSA develop Ventilatory failure) develop Ventilatory failure) Papworth,Cambridge,Sept 2006Papworth,Cambridge,Sept 2006

CPAP=3503

(OSA is one of 87 sleep disorders) Ventilatory

Failure = 385

Bi-level machines used for OSA and in 78 COPD