NIV: When to Start ,How

and When to End?

By

Gamal Rabie Agmy , MD , FCCP

Professor of Chest Diseases ,Assiut

University

Rational of NPPV in COPD

AJRCCM 2001;163:283-91

WHEN to START

Severe

Mild To

moderate

Not established

COPD

exacerbation

Post-extubation

COPD

exacerbation

Hypoxemic

Post-extubation

COPD

Exacerbation

Hypoxemic

Weaning

DNI order

Meaning of NIV use

ARF Severity

TO PREVENT TO AVOID

ETI ALTERNATIVE

to ETI

300 250 200 150 100 50

Low Tidal Volume Ventilation

Higher PEEP

HFO

Prone Positioning

ECMO

Low – Moderate PEEP

Neuromuscular Blockade

PaO2/FiO2

Increasing Severity of Lung Injury

Mild ARDS Moderate ARDS Severe ARDS In

creasin

g I

nte

nsit

y o

f In

terven

tio

n

NIV

ECCO2-R

iNO

The case of ARDS

The interfaces

49%

23/36 (64%) pts survived hospital discharge

The humidification system

Low humidity decreases mucus clearance

Wood KE et al. Respir Care 2000

Noninvasive MV

The ventilator!

YOU HAVE…….

A VENTILATOR HAS NO BRAIN, BUT NEEDS TO COUPLE TWO BRAINS !

WHEN and HOW to STOP

Monitoring

NIV monitoring:

- Evaluate the achievement of objectives

(NIV success and quality control)

- Modify the settings if necessary

Efficacy

Comfort Compliance

NIV

success

What is the NIV failure?

Need for tracheal intubation

When does it happen?

Immediate: < 1 hr

Early : 1- 48 hrs

Late: > 48hrs

NIV FAILURE (%)

Immediate Early Late

17

68

15

Acute on chronic respiratory failure

NIV Failure: Decide Early

Worsening Encephalopathy or Agitation

Inability to Clear Secretion

Inability to Accept Any Interface

Hemodynamic Instability

Worsening Oxygenation

Progressive Hypercapnia, pH <7.20

Persistent tachypnea /tachycardia

Weaning Algorithm

Respir Care 2004. Vol. 49 (1):72-89

NO Continue with

NPPV therapy

Does

patient meet

weaning guidelines?

Clinically stable

RR < 24

HR < 110

pH > 7.35

SpO2 >90%

on< 50%

If patient status does

not improved consider

intubation

NO

YES

Restart NPPV at

previous settings

YES

Trial off NPPV with

supplemental

oxygen

Slowly titrate IPAP

downward in decrements

of 2-3 cm H2O

Does

patient demonstrate

clinical evidence

of respiratory

distress?

Discontinue NPPV and place on

supplemental oxygen

Troubleshooting

pCO2 remained high:

Exclude inappropriately high FiO2

Check mask + circuit for leaks

Check Patient Ventilator Asynchrony

Check expiration valve patent

Increase IPAP

Increase FiO2/EPAP pO2 remained low:

Clinical Deterioration: Consider complications Optimize medical therapy Consider intubation

Gastric distension: Simethicone /Reduce IPAP. Irritation or ulceration of nasal bridge:

Adjust strap tension, Try cushion dressing, Change mask type.

Dry nose or mouth: Add humidifier

Check for leaks.

Dry sore eyes:Check mask fit

Nasal congestion: Decongestants Hypotension: Reduce IPAP

Troubleshooting

Use of Nasogastric Tubes

Use of nasogastric tubes to take air from

the stomach is controversial

The tube increases leaking around the

mask

The tube itself blocks a nasal passage

Compression of tube against the skin by

the mask may increase risk of skin

breakdown

Criteria for Termination of

NPPV for Invasive Ventilation Worsening pH and PaCO2

Tachynpnea (> 30 breaths/min)

Hemodynamic instability

SpO2 < 90%

Decreased level of consciousness

Inability to clear secretions

And inability to tolerate interfaces

Pressure pre-set

(PCV/PSV)

Varying inspiratory volume,

Constant inspiratory pressure

Advantage:

Compensation for leakage,

Best tolerated

Disadvantage:

Instability of tidal volume in

case of increased airway

resistance

Volume pre-set

(VCV)

Constant inspiratory volume,

Varying inspiratory pressure

Advantage:

Stability of tidal volume even in

case of increased airway

resistance

Disadvantage:

high inspiratory pressure,

No leak compensation

Volume versus pressure: No differences in:

• Improvements in sleep quality

• Improvements in blood gases

But:

• More side effects during volume pre-set

Windisch W. et al. Respir Med 2005; 99: 52-59

Volume versus pressure: No differences in:

• Sleep quality

• Blood gases

• Quality of life

• Physical activity

• Spontaneous breathing

Tuggey JM et al. Thorax 2005; 60: 859-864

Hybird modes combine the advantages of pressure pre-set and volume-

pre-set

AVAPS

Average Volume Assured Pressure

Support • Automatic adjustment of inspiratory pressure (range setting)

• Target volume set

• Measurement of inspiratory pressure and expiratory volume

• Calculation of missing patient tidal volume

• Changes of inspiratory pressure (1 cmH2O/min)

Assurance of tidal volume + comfort of pressure pre-set

Non-invasive ventilation for weaning, avoiding reintubation after extubation and in the

postoperative period:a meta-analysis

British Journal of Anaesthesia 109 (3): 305–14 (2012)

A meta analysis of NIV use in selected subgroups of recently extubated patients

suggests that the judicious NIV use may reduce ICU and hospital length of stay,

pneumonia, an reintubation rates and hospital survival.

Noninvasive ventilation as a weaning strategy for mechanical ventilation in

adults with respiratory failure: a Cochrane systematic review

CMAJ, February 18, 2014, 186(3)

Noninvasive weaning reduces rates of death and pneumonia without increasing

the risk of weaning failure or reintubation. In subgroup analyses, mortality benefits were

significantly greater in patients with COPD.

% Intubation

% mortality of NIV failures

Select the good patient Start in the appropriate enviroment , with appropriate ventilator, mode and setting and interface Quickly (in 1-2 hrs) check for improvement of ABGs and consciousness, clinical signs If insufficient check for cause of failure: Secretions, tolerance, synchrony, leaks…. Possibly increasing monitoring Try to manage it (cough assist, change interface, ventilator, setting,….) If success, do not stop to monitor (possible late failure!)

HOWEVER

DO NOT DELAY INTUBATION

In Conclusion .

% Intubation

% mortality of NIV failures