Non-invasive ventilation

1. NON-INVASIVE VENTILATION

2. Objectives:
• Definitions
• Advantages and Disadvantages
• Indications
• Contraindications
• Modes

3. Non-invasive ventilation
“The delivery of mechanical ventilation to the lungs
using techniques that do not require endotracheal
intubation”

4. Background
• Initially used in the treatment of hypoventilation
with Neuromuscular Disease
• Now accepted modality in treatment of acute
respiratory failure

5. Respiratory mechanics
• Respiratory effort required for inspiration needs
to overcome
– Elastic work (stretch)
– Flow resistance work ( airway obstruction)
• Respiratory failure – forces opposing inspiration
exceed respiratory muscle effort

6. Respiratory failure
Failure to maintain adequate gas exchange
• Hypoxic ( Type 1)
or
Hypercapnic /Hypoxic (Type 2)
• Acute /Chronic / Acute on Chronic

7. Effects of NIV
• Improves alveolar ventilation to reverse
respiratory acidosis and hypercarbia
• Recruits alveoli and increases FRC to reverse
hypoxia
• Reduces work of breathing

9. Advantages
Noninvasiveness
• Application - easy to implement or remove
• Improves patient comfort
• Reduces the need for sedation
• Oral patency
(preserves speech, swallowing, and cough)

10. Advantages 2
• Avoid the resistive work of ETT
• Avoids the complications of ETT
– Early (local trauma, aspiration)
– Late (injury to the the hypopharynx, larynx,
and trachea, nosocomial infections)
• Reduced Cost and Length of Stay

11. Disadvantages
1.System
Slower correction of gas exchange abnormalities
Gastric distension (occurs in <2% patients)
2.Mask
Air leakage
Eye irritation
Facial skin necrosis (most common complication)

12. Disadvantages
3.Lack of airway access and protection
Suctioning of secretions
Aspiration
4. Compliance / claustrophobia
5. Work load and supervision

13. Which mode?
• Hypoxaemia = CPAP
• Hypercapnia and hypoxaemia= Bi Level

14. CPAP
CONTINUOUS POSITIVE AIRWAY PRESSURE (AKA PEEP)
• Constant positive airway pressure throughout cycle
• Improves oxygenation
• Decreases work of breathing by alveolar recruitment (Dec
elastic work) and unloads insp muscles
• Decreases hypoxia by alveolar recruitment and reduces
intrapulmonary shunt

15. Indications
• Acute pulmonary oedema
• Pneumonia

16. Bi-level Pressure Support
• Combination of IPAP and EPAP
Inspiratory PAP = Pressure Support
Expiratory PAP = CPAP

17. Respiratory Effects Bi-PAP
• EPAP
– Provides PEEP
– Increases Functional Residual Capacity
– Reduces FiO2 required to optimise SaO2
• IPAP
– Decreases work of breathing + oxygen demand
– Increases spontaneous tidal volume
– Decreases spontaneous respiratory rate

18. Indications for Bi Level
• Acute Respiratory Failure
• Chronic Airway Limitation/COPD
• Asthma?

19. When to use NIV/CPAP
• Indication: APO, COAD
• Contraindications excluded
• Assessment
– Sick not moribund
– Able to protect airway
– Conscious/cooperative
– Haemodynamic stability
• Premorbid state / Ceiling of therapy?

20. Contraindications
• Impaired consciousness, confusion, agitation
• Inability to protect airway
• Excessive secretions or vomiting
• Haemodynamic instability
• Untreated pneumothorax
• Bowel obstruction
• Facial trauma, burns, recent surgery
• Fixed upper airway obstruction

21. Complications
• Hypoxia
• Pulmonary barotrauma
• Reduced cardiac output
• Vomiting and aspiration
• Pressure areas
• Gastric distension

23. Ventilator Settings- LVF
• CPAP at 5-8 and increase to 10-15 cm H20
• Mask is held gently on patient’s face.
• Increase the pressures until adequate Vt
(7ml/kg), RR<25/min, and patient comfortable.
• Titrate FiO2 to achieve SpO2>90%.
• Keep peak pressure <25-30 cm

24. COAD exacerbation: NIV
• increases pH, reduces PaCO2, reduces the
severity of breathlessness in first 4 h of
treatment
• decreases the length of hospital stay
• mortality and intubation rates are reduced

25. Ventilator settings COAD
• Mode- Spontaneous/Timed
• EPAP- 4-5 cm H20 IPAP- 12- 15 cm H20
• Trigger- maximum sensitivity
• Back up rate- 15 breaths/min
• Back up I:E 1:3

26. Setting It Up
• No contraindications
• O2 medical therapy underway
• Explanation and reassurance
• Correct mask size
• Ventilator set up
• Commence NIV hold mask in place
• Reassure and fix mask
• Monitor and observe, regular assessment

27. Monitoring response
Physiological
a) Continuous oximetry
b) Exhaled tidal volume
c) ABG- Initial, 1, 2-6 hrs
Objective
a) Respiratory rate
b) Chest wall movement
c) Coordination of respiratory effort with NIV
d) Accessory muscle use
e) HR and BP
f) Mental state
Subjective
a) Dyspnoea
b) Comfort

28. Documentation
• Mode of ventilation
• Flow rate of oxygen, percentage of oxygen
• TPR and BP
• Respiratory assessment
• Conscious level (GCS)
Obs - 15 minutely for first hour, then hourly if condition stable

29. Treatment Failure
• Deterioration in condition
• Worsening or non improving ABG
• Intolerance or failure to coordinate with machine

30. Treatment Failure
• Back to the patient- ABC
• Medical therapy optimised
• Treatment of complications

31. Criteria to discontinue NIV
• Inability to tolerate the mask
• Inability to improve gas exchange or dyspnoea
• Need for endotracheal intubation
• Hemodynamic instability
• ECG – ischaemia/arrhythmia

32. Withdrawal of NIV
• Clinical improvement
• Aim for
– RR<24
– HR <110
– pH>7.35
– Sats >90% on <40%

33. Most important THPs
• Selection of patient really vital to success - need
to have reversible pathology
• Aim for gradual improvement over hours with
good supportive nursing
• In ED, main use is to avoid intubation /
ventilation in LVF and COAD