All About Home NIV

All About Home NIVAll About Home NIV

Respiratory MechanicsRespiratory Mechanics

Spontaneous BreathingSpontaneous Breathing

Filtre Warm inspired gas humidification

Upper airwaysUpper airwaysNose functionsNose functions

What is spontaneous ventilation?What is spontaneous ventilation? Purpose of ventilation

‐ Supply fresh gas to the lungs, to be exchanged at the alveolar-capillary level

through blood circulation

‐ Provide cells with adequate 02 (Oxygenation)

‐ get rid of CO2 (Alveolar ventilation)

‐ Maintain normal acid base balance

Arterial Blood Arterial Blood GGasesasesNormal valuesNormal values

‐ ABGs: Arterial Blood Gases

• Pa02 and PaC02

‐ Oxygenation assessment

• Pa02 80-100 mmHg

• Sa02: 92% to 100%

‐ Ventilation assessment

• PaC02: 35-45 mmHg

‐ Acid base status• pH:7,35-7,45

Some Some DDefinitionsefinitions

Tidal Volume (Vt)‐ Quantity of air in the lungs in 1 inspiration

Minute Ventilation‐ Quantity of air in the lungs in 1 min (= Vt x respiratory

rate) Hypoxemia

‐ state in which Pa02<60 mmHg (in the blood)

‐ Sa02<92% (Oxygen saturation)

Hypoxia

‐ state in which there is inadequate 02 at the tissue level

Some Some DDefinitionsefinitions

Hypercapnia

‐ when PaC02 >45mmHg

Hypocapnia

‐ when PaC02<35mmHg

Acidosis:‐ pH<7,35

Alkalosis:‐ pH>7,45

Spontaneous breathingSpontaneous breathing

At Rest

Pressures Equal

No Air Flow


On Inspiration: Active phenomena

Muscles Contract

Pressure Changes

Air Flows Into

Lungs


On Expiration: passive phenomena

Muscles Contract

Pressure Changes

Air Flows out

Lungs


End Expiration: Intrinsic PEEP

Extra work is needed to generate the following inspiration

Resistance creates a residual pressure at the end of expiration


Opposing Forces to Ventilation

Elastic recoil Resistance

of the lungs to airflow

Work of Breathing

Opposing Forces to VentilationOpposing Forces to Ventilation

Tendency of the Lungs to Resist Inflation

Pressure / Volume = Elastance

Resistance to Air Movement in the Airways

Pressure / Flow rate = Airways Resistance

Breathing with Lung DiseaseBreathing with Lung Disease

Decreased Elastance Increased Resistance

Stronger Muscle Contractions Required

Larger Patient Effort

Excessive Work of Breathing

Respiratory Failure

Breathing with Lung DiseaseBreathing with Lung Disease

Flow and/or Volume

Normal

Disease

Patient Effort

Consequences of Respiratory FailureConsequences of Respiratory Failure

Excessive Work of Breathing

Respiratory Muscle Dysfunction

Inadequate Alveolar Ventilation

Severe Hypoxia

Goals of Ventilatory SupportGoals of Ventilatory Support

Improve Alveolar Minute Ventilation

Decrease the Work of Breathing

Correct Gas Exchange Abnormalities

Types of Ventilatory Types of Ventilatory SSupportupport

Invasive‐ endotracheal tube‐ tracheostomy

Noninvasive‐ mask

Home NIV ObjectivesHome NIV Objectives

Correct hypoventilation and associated syndromes (like OSA):‐ Despite the leaks‐ Ensuring a good comfort‐ Preserving a good quality of sleep

Provide a comfortable ventilation to ensure a good patient compliance‐ May prefer comfortable parameters (IPAP, EPAP, RR) with a

higher CO2 level

‐ Adapt the patient to his therapy takes time: if it has already failed once then it is even more difficult the second time!

Expected ResultsExpected Results

Restrictive pathologies Obstructive pathologies

Short Term

• Symptoms relief• Reduce desaturations

• Symptoms relief• Reduce desaturations and increase ventilation (overcome oxygen side effect)

Long Term

• Reduce Pa C02• Improve survival• Reduce decompensation episodes

• Reduce Pa CO2• Improve quality of life• Reduce decompensations episodes risks (or at least severity)

Which pathologies would Which pathologies would benefits from Home NIV?benefits from Home NIV?

What is CRF?What is CRF?

Chronic respiratory failure (CRF) may result from different pathologies, which make the body inept to bring oxygen and/or wash out its CO2.

As a result there is a decrease of the PaO2 (hypoxemia)

and/or an increase of the Pa CO2 (hypercapnia) noticed

during blood gases analysis

Chronic Respiratory Failure Chronic Respiratory Failure Patients ManagementPatients Management

« The management strategy is based on an individualized assessment of disease severity and response to various therapies. »

Source: Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary DiseaseGOLD scientific committee - NHLBI/WHO workshop summary - AJRCCM 2001GOLD scientific committee - NHLBI/WHO workshop summary - AJRCCM 2001

Therapy depends upon the patient’s Therapy depends upon the patient’s pathology type and severitypathology type and severity

COPD and VentilationCOPD and Ventilation

COPD Patient COPD Patient Some definitionsSome definitions

COPD Chronic Obstructive Pulmonary Disease is the name given to

the progressive narrowing of the airways This narrowing may result from an obstruction of the airways

in patients with Chronic Bronchitis (scarring of the airways and sputum secretion) or emphysema

Emphysema Emphysema is brought about by cigarette smoking which results in

chemical changes that destroy lung tissue:‐ Loss of lung tissue: reduction of elasticity‐ Airways tend to close

COPD COPD

Chronic BronchitisEmphysema

Swollen airways

Narrowed airwaysPhlegm damages the tissue

Alveoli collapse

Pink pufferPink pufferEmphysema dominantEmphysema dominant

Blue bloaterBlue bloaterBronchitis dominantBronchitis dominant

COPDCOPD

COPD Patient COPD Patient TherapiesTherapies

Source: Global Strategy for the Diagnosis, Management, and Preventation of Chronic Obstructive Pulmonary DiseaseGOLD scientific committee - NHLBI/WHO workshop summary - AJRCCM 2001GOLD scientific committee - NHLBI/WHO workshop summary - AJRCCM 2001

<70% FEV1/FVC <30%

Drugs & Physiotherapy

Long Term Oxygen Therapy

Noninvasive Ventilation

Moderate stage

Worsening airflow limitation

Severe stage

Severe airflow limitation

Mild stage

Mild airflow limitation

« As the disease progresses, hypoxemia occurs and hypercapnia is seen in advanced disease »

COPD Patient COPD Patient Oxygen TherapyOxygen Therapy

LTOT (12-17hrs/day) has been shown to ‐ Increase survival‐ Decrease hospitalization rate

Adverse effects:

‐ Hypoventilation and CO2 retention

‐ Increased PaCO2 at night may contribute to arousals

‐ Sudden High PaCO2 deteriorate the gas balance and may lead to acidosis (exacerbation risks)

COPD PatientsCOPD PatientsHome NIVHome NIV Therapy Therapy

Conflicting results of studies COPD population likely to benefit from NIPPV :

‐ Substantial daytime CO2 retention‐ Severe airway obstruction‐ Nocturnal oxygen desaturation

Benefits:‐ Reduce nocturnal hypoventilation: allows respiratory centre to reset,

improves daytime hypercapnia. ‐ Improve sleep quality by reduced episodes of hypoventilation and

desaturations ‐ Resting chronically fatigued respiratory muscles, allowing recovery of

inspiratory muscle function‐ Decrease Decompensation episodes risks/severity

Benefits: improve patient quality of life

Source: Consensus conference : « Clinical indications for noninvasive positive pressure ventilation in chronic respiratory failure due to restrictive lung disease, COPD and Nocturnal hypoventilation » Chest 1999

COPD Patient & NonInvasive VentilationCOPD Patient & NonInvasive Ventilation

Gas exchange criteria

‐ Daytime PaCO2 > 55 mmHg or

‐ Nocturnal oxygen desaturation : SaO2 < 88% for > 5 min sustained while receiving oxygen therapy (<2l)

‐ PaCO2 of 50-54 mmHg and hospitalization related to recurrent episodes of hypercapnic respiratory failure (> 2 episodes in 1 year)

Source: Consensus conference - Chest 1999

Criteria usually followed in the daily practice:• Repeated decompensation episodes in the last 3 months• High CO2 level• Acceptation of the therapy (compliance: 8hrs ventilation at night)

Evidence Statements from NICEEvidence Statements from NICE

Addition of NIV to LTOT improved daytime PaCO2 during oxygen breathing

Resting dyspnoea improved in NIV+LTOT group, and was significantly better at month 24

After 2 years QOL was significantly improved Overall hospital admissions decreased by 45% in the NIV+LTOT

group compared with increase of 27% in LTOT (follow back period of 12 months)

http://thorax.bmjjournals.com/content/vol59/suppl_1/

NICE RecommendationNICE Recommendation

Adequately treated patients with chronic hypercapnic respiratory failure who have required assisted ventilation (whether invasive or non-invasive) during an exacerbation or who are hypercapnic or acidotic on LTOT should be referred to a specialist centre for consideration of long-term NIV.

Chronic Obstructive Pulmonary Disease: National clinical guideline on management of chronic obstructive pulmonary disease in adults in primary and secondary care

Thorax 2004;59(suppl 1) 1-232

Restrictive Patients and Restrictive Patients and VentilationVentilation

Restrictive PatientsRestrictive PatientsDifferent DiseasesDifferent Diseases

Obese Hypoventilation Chest wall deformities

‐ Kyphoscoliosis‐ Sequel of tuberculosis

Non progressive or slowly progressive neuromuscular disorders‐ Central hypoventilation‐ Spinal cord injury, spinal muscular dystrophy‐ Myopathies‐ Sequel of Poliomyelitis

Progressive neuromuscular disorders‐ Amyotrophic Lateral Sclerosis (ALS)‐ Duchenne muscular dystrophy

Restrictive PatientsRestrictive Patients Pathology ProgressionPathology Progression

Source: book “Assistance Ventilatoire à Domicile”D Robert, B.J. Make, P Léger, A. L. Goldberg, J. Paulus, T. Willig – 1994D Robert, B.J. Make, P Léger, A. L. Goldberg, J. Paulus, T. Willig – 1994Source: Consensus Conference - Chest 1999Consensus Conference - Chest 1999

<50% FVC <20%

Moderate stage Severe stageMild stage

Invasive ventilationNoninvasive Ventilation

Physiotherapy

Restrictive PatientsRestrictive Patients

“More recent reviews have cited the advantages of pressure targeted devices for comfort and their ability to compensate for leaks. Volume targeted equipment may be favorable for many patients simply because triggering mechanism are more adjustable and pressure targeted systems are not able to guarantee a minimum minute ventilation.”

Source: Consensus Conference - Chest 1999

10 years ago: Invasive ventilation/volume at the late stage of the disease Today:

‐ Start at the early stage in pressure support‐ Use security functions while patient becomes dependant‐ Ends up with invasive ventilation (< 5% of patients)

Restrictive PatientsRestrictive Patients When shall we start NIV?When shall we start NIV?

Gas exchange criteria‐ PaCO2 > 45mmHg

‐ Or SaO2<88% during 5min

‐ Or VC<50% of predicted

Source: Consensus conference - Chest 1999

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