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Non-Invasive Ventilation Arjun Srinivasan, Mahadevan & Pattabhiraman Pulmonology Associates KMCH.

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Presentation on theme: "Non-Invasive Ventilation Arjun Srinivasan, Mahadevan & Pattabhiraman Pulmonology Associates KMCH."— Presentation transcript:

1 Non-Invasive Ventilation Arjun Srinivasan, Mahadevan & Pattabhiraman Pulmonology Associates KMCH

2 Agenda Definition & mechanism of action Indications When, who, where, what & how ? Technical aspects Weaning off NIV Complications

3 NONINVASIVE VENTILATION Non-invasive ventilation (NIV) refers to a form of assisted ventilation that involves provision of ventilatory support without endotracheal intubation (ETI)

4 CPAP vs. NIV CPAP Pressure greater than atm applied to proximal airway throughout resp cycle Splints airway Increases lung volume Raises intrathoracic pressures Does not offload resp muscles NIV Greater pressure applied during inspiration over and above the baseline CPAP Unloads resp muscles Can provide complete resp support

5 NIV – how it works Decreasing work of breathing Off loading of resp muscles & decreasing fatigue Preventing wide swings in intrathoracic pressure Decreasing afterload to heart Preventing complications of IMV Intubation & MV Loss of airway defenses Post extubation issues

6 NIV Whom to initiate ? AcuteCOPD Pulmonary edema Immunocompromised patients Weaning from mechanical Neuromuscular weakness Bronchial asthma ARDS Do not intubate – pts Other indications Chronic

7 When to initiate ? Appropriate diagnosis with potential reversibility Establish need for ventilatory assistance Moderate to severe respiratory distress Tachypnea Accessory muscle use or abdominal paradox Blood gas derangement pH <7.35 Paco2 >45 mm Hg Pao2/Fio2 < 200

8 When not to initiate Respiratory arrest Medically unstable Unable to protect airway Excessive secretions Uncooperative or agitated Unable to fit mask Recent upper airway or gastrointestinal surgery

9 Who will initiate ? Clinicians Respiratory therapists Trained nurses

10 Where to initiate ? EmergencyICUs Step-down units Wards

11 Which ventilator to use ? ICU ventilatorBIPAP

12 Critical care ventilator Vs NIV Variables … Inspiratory Pressure … Leak Tolerance … Different Modes … Alarms … Monitoring Capability … Battery … Oxygen Blender … Compactness ICU VentilatorNIV ++ +++ + ++- +++

13 Mask interface

14 Pro & cons of interfaces Ideal interface  Low dead space  Transparent  Lightweight  Easy to secure  Adequate seal with low facial pressure  Disposable or easy to clean  Non-irritating (non-allergenic) Inexpensive  Variety of sizes  Adaptable to variations in facial anatomy  Ability to be removed quickly  Anti-asphyxia mechanism  Compatible with wide range of ventilators

15 Vented & Non-vented masks

16 Tubings Depends on the type of ventilator being used 1.BIPAP 2.Intermediate type of ventilator 3.Critical care ventilators

17 Modes CPAP Bi-level - S (spontaneous) Bi-level - S/T PC Volume preset Vs Pressure preset Dual modes

18 How to set pressures ? IPAP & EPAP High-low approach High inspiratory pressures (20-25 cms), rapidly titrated to ensure adequate tolerance & ventilation in the first hour Similarly EPAP is adjusted from high (10) to low levels Rapidly addresses hypoxemia Low-high approach Low initial inspiratory pressures (10-12 cms) and rapid upward titration to ensure adequate ventilation in the first hour Low initial inspiratory pressures (10-12 cms) and rapid upward titration to ensure adequate ventilation in the first hour EPAP is titrated upward from 4-5 cms Better tolerance Aim for TV ~ 6-7 ml/kg predicted body weight

19 Trigger Most portable ventilators have flow triggering Pressure triggering : associated with increased work of triggering with auto PEEP (in AE of COPD) Auto PEEP significantly lower with flow triggering in PSV mode Modern ventilators allow manipulation of trigger sensitivity to allow reduction in work of breathing ST mode offers a timed back up trigger

20 FiO2 Most portable BIPAP machines lack O2 blender and are dependent on oxygen delivery from wall units/cylinder FiO2 delivered is not constant & is dependent on the flow rates / inspiratory pressures / site of leak port / air leak Oxygen delivered through ICU ventilators is regulated & precise due to blender. Delivery upto FiO2 of 1 possible

21 Humidification Area of intense debate with no clear consensus High flow rates over long hours tend to dry up secretions Dried up upper airway adds to discomfort Probably a good idea in cases of prolonged NIV Heated humidification is the way to go with lesser intensity than in intubated patients HME is strict no as it adds to dead space & interferes with CO2 wash out

22 Monitoring during NIV Subjective and objective parameters First 2hrs - intense monitoring First 2hrs - intense monitoring Next 8hrs - close monitoring … Next 8hrs - close monitoring … There after - routine monitoring There after - routine monitoring Even if parameters were borderline at start of NIV, early change / improvement predicts success of NIV This is the most important aspect of NIV First few hours predict the outcome of the patient

23 Monitoring during NIV … Look at patient, ventilator, interface, bed side monitor, ABG … Patient - Comfort, conscious level Chest expansion Accessory muscles Synchrony … Interfaces - leak, tightness … Trigger, volume delivered, cycling … HR, RR, SpO2, BP … ABG - pCO2, pH, pO2 at base line, 1-2hrs after, then based on response

24 Other settings Tinsp Inspiratory time of backup rate in st mode Rise time Time taken for IPAP to be reached from EPAP Shorter in tachypneic patients may ensure better tolerance Ramp time Time taken to reach set EPAP/IPAP Relevant in chronic ventilation

25 Trouble shooting Potential issues 1.Leak 2.Agitation / asynchrony 3.Hypoxia 4.Hypercarbia Solutions 1.Check mask fit/ strap position/ tubings / ? Chin strap 2.Talk to patient / adjust settings / sedation /analgesia 3.Adjust ventilator / FiO2/ intubate 4.Adjust ventilator / FiO2/ intubate

26 Potential indicators of success in NIV … Younger age … Lower acuity of illness … Able to cooperate … Better neurologic score … Less air leak … PaCO2 45 - 92 mmHg … pH 7.10 - 7.35 … Synchronous breathing … Intact dentition … Less secretions … Better compliance … Improvements in gas exchange and heart respiratory rates within first 2 hours

27 Situations where NIV is likely to fail Hypercapnic failure GCS < 11 RR > 35/min PH < 7.25 APACHE > 29 Asynchrony Agitation / intolerance Edentulous / excessive leak No initial improvement Hypoxemic failure Diagnosis of ARDS / pneumonia Age > 40 SBP < 90 Metabolic acidosis PH < 7.25 Low PO2/ FiO2 Simplified APS II > 34 Failure of PO2 / FiO2 to improve above 175 by 1 st hour

28 Weaning patients from NIV No specific protocol Pts of COPD would require at least 24 hours to stabilise NIV is usually removed as per patient’s request for feeding/facial hygiene Re – attached as deemed necessary Attempt gradual decrease in IPAP / EPAP & discontinue when patient tolerates

29 Complications of NIV Failure is the most serious complication Most dreaded complication is failure to recognize NIV failure early leading to delay in intubation Studies have shown that this can lead to increased mortality especially when used in situations where NIV is used without strong evidence

30 Complications of NIV Principles of mechanical ventilation. 3e

31 Summary & conclusions NIV is an important tool in the hands of RT & intensivist Provides a level of respiratory support in emergency / wards unimaginable otherwise Has changed the way we manage COPD exacerbations Needs careful monitoring during initial hours A tool which needs to be used wisely for us to reap the benefits

32 Thank you Questions ?

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