Non-Invasive Non-Invasive VentilationVentilation

Dr Duncan MitchellDr Duncan Mitchell

Ealing HospitalEaling Hospital

What we are going to What we are going to cover…cover…

What is NIV?What is NIV? Ventilation Physiology & Ventilation Physiology &

TerminologyTerminology Types of NIVTypes of NIV Indications for NIVIndications for NIV Contra-indicationsContra-indications Case examplesCase examples

What is Non-Invasive What is Non-Invasive Ventilation (NIV)Ventilation (NIV)

‘‘Delivery of ventilatory support Delivery of ventilatory support without the need for an invasive without the need for an invasive artificial airway’artificial airway’

Some Some Physiology…….zzzzzzz!Physiology…….zzzzzzz!

VentilationVentilation- process by which O2 and CO2 are - process by which O2 and CO2 are transported to and from the lungstransported to and from the lungs

Venous blood Venous blood - lower pO2 higher pCO2 than - lower pO2 higher pCO2 than inspired gasinspired gas- partial pressure gradient driving - partial pressure gradient driving O2 in and CO2 outO2 in and CO2 out

Ventilation of lungs with inspired gases Ventilation of lungs with inspired gases leads to mixing with alveolar gasleads to mixing with alveolar gas

If no ventilation at all, no If no ventilation at all, no replenishment of O2 and no removal of replenishment of O2 and no removal of CO2CO2

Arterial pO2 falls and pCO2 rises Arterial pO2 falls and pCO2 rises towards that of venoustowards that of venous

If ventilation greater than needed, If ventilation greater than needed, alveolar gas closer to inspired gasalveolar gas closer to inspired gas

TerminologyTerminology

Tidal Volume (VT) – amount of gas Tidal Volume (VT) – amount of gas expired per breath (~ 500ml at rest)expired per breath (~ 500ml at rest)

Minute Volume – amount of expired gas Minute Volume – amount of expired gas per minuteper minute

Alveolar Ventilation – amount of gas Alveolar Ventilation – amount of gas reaching functional alveolireaching functional alveoli

Work of Breathing – usually ~5% of Work of Breathing – usually ~5% of total body work – most used to total body work – most used to overcome lung and chest wall stiffness overcome lung and chest wall stiffness during inspirationduring inspiration

PEEPPEEP Pressure Support (cmH2O) – Pressure Support (cmH2O) –

positive pressure applied to airway positive pressure applied to airway to support patients own breathto support patients own breath

Opening Pressure – pressure Opening Pressure – pressure required to open collapsed alveolirequired to open collapsed alveoli

Types of NIVTypes of NIV

Negative-Pressure Ventilation (Iron Negative-Pressure Ventilation (Iron Lung)Lung)

Continuous Positive Airway Continuous Positive Airway Pressure (CPAP) (Not really NIV!)Pressure (CPAP) (Not really NIV!)

Bi-level Positive Airway Pressure Bi-level Positive Airway Pressure (BiPAP)(BiPAP)

Negative-Pressure Negative-Pressure VentilationVentilation

Late 1880s – iron lungs Late 1880s – iron lungs first usedfirst used

Early 1900s – iron lungs Early 1900s – iron lungs used for polio epidemicsused for polio epidemics

This continued This continued throughout the 20throughout the 20thth century until 1960s century until 1960s when invasive when invasive ventilation became ventilation became availableavailable

CPAPCPAP

Nasal or face maskNasal or face mask Continuous positive pressure Continuous positive pressure

applied to the airwaysapplied to the airways Usually well-toleratedUsually well-tolerated Similar to use of PEEPSimilar to use of PEEP Reduces work of breathingReduces work of breathing Improve ventilation to Improve ventilation to

collapsed areas of lungcollapsed areas of lung

BiPAPBiPAP

Bi-Level pressure supportBi-Level pressure support Inspiratory Positive Airway Pressure Inspiratory Positive Airway Pressure

(IPAP) & Expiratory PAP (EPAP)(IPAP) & Expiratory PAP (EPAP) IPAP is the pressure support machine IPAP is the pressure support machine

gives to help patients own inspirationgives to help patients own inspiration Helps to reduce WOB and increase Helps to reduce WOB and increase

alveolar ventilationalveolar ventilation EPAP is essentially PEEP and help to EPAP is essentially PEEP and help to

prevent alveolar collapseprevent alveolar collapse

Indications for CPAPIndications for CPAP

Cardiogenic Pulmonary OedemaCardiogenic Pulmonary Oedema Obstructive Sleep ApnoeaObstructive Sleep Apnoea Chest Wall Trauma if hypoxic on Chest Wall Trauma if hypoxic on

adequate analgesiaadequate analgesia PneumoniaPneumonia

Indications for BiPAPIndications for BiPAP Exacerbation of COPD with Respiratory Exacerbation of COPD with Respiratory

acidosisacidosis Type II respiratory failure with chest wall Type II respiratory failure with chest wall

deformity or neuromuscular diseasedeformity or neuromuscular disease Failure of CPAPFailure of CPAP Pneumonia with respiratory acidosisPneumonia with respiratory acidosis Therapeutic trial with a view to intubation Therapeutic trial with a view to intubation

if it failsif it fails Others (ARDS, post-op respiratory failure, Others (ARDS, post-op respiratory failure,

to buy time prior to intubation)to buy time prior to intubation)

Patient SelectionPatient Selection

Sick but not moribundSick but not moribund Able to protect airwayAble to protect airway Conscious and co-operativeConscious and co-operative Haemodynamically stableHaemodynamically stable No excessive secretionsNo excessive secretions Few co-morbiditiesFew co-morbidities Improvement on ABG with NIVImprovement on ABG with NIV

Patient RejectionPatient Rejection

Respiratory arrestRespiratory arrest Haemodynamically unstableHaemodynamically unstable UncooperativeUncooperative Unable to protect airway (swallowing Unable to protect airway (swallowing

and cough impaired or vomiting)and cough impaired or vomiting) Facial, oesophageal, or gastric surgeryFacial, oesophageal, or gastric surgery Craniofacial trauma or burnsCraniofacial trauma or burns Airway obstructionAirway obstruction Undrained PneumothoraxUndrained Pneumothorax

Case 1Case 1

76yr old female76yr old female Lifelong smokerLifelong smoker 1/52 productive cough1/52 productive cough BP140/90 P120 RR40 SaO2 89% on 10LBP140/90 P120 RR40 SaO2 89% on 10L

pH pH 7.37.3pCO2 pCO2 8.28.2pO2 pO2 6.96.9HCO3HCO3 2020BE BE – 4.2– 4.2

Case 2Case 2

83yr old man83yr old man Known IHD, previous MIKnown IHD, previous MI Wife says he has “not been well”Wife says he has “not been well” BP170/95 P120 RR38 SaO2 87% on 15LBP170/95 P120 RR38 SaO2 87% on 15L

pHpH 7.287.28pCO2pCO2 5.25.2pO2pO2 7.17.1HCO3HCO3 2121BEBE -3.2-3.2

Case 3Case 3 49yr old man49yr old man 2/52 Hx of feeling unwell with D&V2/52 Hx of feeling unwell with D&V Not eating or drinkingNot eating or drinking Not passing urineNot passing urine BP89/50 P130 RR40 SaO2 96% on NRBMBP89/50 P130 RR40 SaO2 96% on NRBM

pHpH 6.986.98pCO2pCO2 2.92.9pO2pO2 14.214.2HCO3HCO3 13.913.9BEBE -21.4-21.4

Case 3 Contd….Case 3 Contd….

Urea Urea 3232 Creat Creat 444444 K K 6.26.2 Hb Hb 9.29.2 WCC WCC 2424 PLTPLT 4747 PT PT 2020 APTTAPTT100100

Case 4Case 4

50yr old man50yr old man On the wardOn the ward Nurses report that he snores a lotNurses report that he snores a lot Wife tells you he has seen a Wife tells you he has seen a

specialist and has a machine at specialist and has a machine at home that makes a lot of noisehome that makes a lot of noise

What is it ???!!!What is it ???!!!

SummarySummary

What NIV is and the different typesWhat NIV is and the different types Basic respiratory physiologyBasic respiratory physiology Indications for NIVIndications for NIV When not to use itWhen not to use it Thought about some casesThought about some cases

Any Questions?Any Questions?

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