NON-INVASIVE VENTILATION

Israel E. Priel, MD, FCCPThe Edith Wolfson Medical Center

Holon

History of NIV

• And the Lord God formed man of the dust of the ground and breathed into his nostrils the breath of life and man became a living soul – GENESIS

The Prophet Elisha

Elisha raising the son of the ShunamiteFrederic Leighton , 1881

Eugene Woillez invented the Spirophore in 1876

Alexander Graham Bell

• Designed a prototype of iron lung to be used with a newborn

Polio epidemics of 1930’s 40’s and 50’

Function of Negative Pressure Ventilators

• Negative Pressure is applied intermittently to the thoracic area resulting in a pressure drop around the thorax

• The negative pressure is transmitted to the pleural space and alveoli creating a pressure gradient between inside the lungs and the mouth

• As a result: gas flows into the lungs

Negative Pressure Ventilation

• Negative Pressure Ventilation fell out of favor in the 1960’s

• Cuirass Ventilation

Abdominal Displacement VentilatorsThe Rocking Bed

Abdominal displacement Ventilators Pneumobelt

Diaphragmatic Pacing

Frog Breathing

Glossopharyngeal Breathinghttp://www.youtube.com/watch?

v=Dy1QDIM-rPI

RESPIRATORY FAILURE

• Acute Hypoxemic Respiratory Failure– PO2 < 60 mm Hg on high flow O2

• Acute Hypercapnic Respiratory Failure : ineffective Ventilation– Acute increase : pCO2 > 45 or pH < 7.35

• Acute Respiratory Failure (combined)– Acute increase PCO2 > 45 with increased A-aDO2

• Acute on Chronic Respiratory failure– COPD– Obesity – Hypoventilation– Neuromuscular Diseases– Thoracic Cage abnormalities

Invasive Mechanical Ventilation

• Invasive positive pressure ventilation superceded negative pressure ventilation, primarily due to better airway protection.

Mechanical Ventilation

• Standard of Care until use of NIV• Numerous complications Lung injury, VAP, GI

Bleeding, superinfection etc.• Uncomfortable : sedation and paralysis• High Mortality > 30 %• High Cost• Prolonged LOS (length of stay )

Complications of Mechanical Ventilation

• Related to the process of intubation and mechanical Ventilation

• Caused by loss of airway protective mechanisms

• Occurring after removal of the endotracheal tube

Non-Invasive VentilationDefinition

• Non Invasive Ventilation is the delivery of ventilatory support without the need of an invasive artificial airway

• Eliminates the need for intubation and tracheostomy

• Preserving normal speech, swallowing and cough mechanisms

• Reduces the need for sedation, and the risk of potential airway trauma and nosocomial pneumonia

Non-Invasive Ventilation

Negative-pressure ventilation• Lower the pressure

surrounding the chest wall during inspiration and reversing the pressure to atmospheric level during expiration.

• These devices augment the tidal volume by generating negative extrathoracic pressure

•

Non- invasive Positive-pressure ventilation

• Provided by a • volume ventilator,• pressure-controlled

ventilator, • a bi-level positive airway

pressure (BiPAP) or • a continuous positive

airway pressure device (CPAP)

Noninvasive Ventilation

• Potential of providing mechanical ventilatory assistance with greater:

• Convenience• Comfort• Safety and• Less Cost Than conventional ventilation May reduce infectious complications associated

with mechanical ventilation

Noninvasive Positive Pressure Ventilation

• Positive pressure ventilators, whether invasive or noninvasive, assist ventilation by delivering pressurized gas to the airways, increasing transpulmonary pressure, and inflating the lungs.

• P transpulmonary = Pao - Ppl• Exhalation then occurs by means of elastic recoil of the lungs and any

active force exerted by the expiratory muscles. • The major difference between invasive and NPPV is that with the

latter, gas is delivered to the airway via a mask or "interface" rather than via an invasive conduit.

• The open breathing circuit of NPPV permits air leaks around the mask or through the mouth, rendering the success of NPPV critically dependent on ventilator systems designed to deal effectively with air leaks and to optimize patient comfort and acceptance.

Mechanism of Benefit from NIV

• Improved Alveolar Ventilation• Reduced Work of Breathing• Rest of the respiratory musculature• Offsets intrinsic PEEP (auto-PEEP) that may

occur in COPD• Reduces V/Q mismatches in Pulmonary Edema• Reverse of lung microatelectases -> improved

compliance

Mechanism of Benefit from NIVHow does it decrease Mortality?

• Decrease Hospital acquired infections• Decreased VAP• Decreased Trauma from Intubation• Less complications of sedation

Who can provide NIV?

• Physicians, Nurses, Resp. Therapists• Experienced staff is needed for monitoring

and managing complications• For the first few hours one to one attention is

mandatory by a skilled and experienced physician/ nurse or RT

• The presence of personnel skilled in invasive airway management

ModalitiesCPAP

• CPAP – Continuous Positive Airway Pressure Ventilation

• Improves oxygenation by recruiting collapsed alveoli

• Pressures commonly used to deliver CPAP to patients with acute respiratory distress range from 5 to 12.5 cm H2O.

Ventilators for NPPVCPAP

• Delivery of CPAP. • Not a true ventilator mode because it does not actively assist inspiration• CPAP is used for certain forms of acute respiratory failure. • By delivering a constant pressure during both inspiration and expiration, CPAP increases

functional residual capacity and opens collapsed or underventilated alveoli, thus decreasing right to left intrapulmonary shunt and improving oxygenation.

• The increase in functional residual capacity may also improve lung compliance, decreasing the work of breathing .

• By lowering left ventricular transmural pressure, CPAP may reduce afterload and increase cardiac output , making it an attractive modality for therapy of acute pulmonary edema.

• By counterbalancing the inspiratory threshold load imposed by intrinsic positive end-expiratory pressure (PEEPi), CPAP may reduce the work of breathing in patients with COPD .

• A few uncontrolled trials have observed improved vital signs and gas exchange in patients with acute exacerbations of COPD treated with CPAP alone , suggesting that this modality

may offer benefit to these patients.

ModalitiesBiPAP

• BiPAP – Bilevel Positive Airway Pressure Ventilation• Provides a boost of pressure during inspiration• Pressure Support ( IPAP – EPAP)• IPAP (Inspiratory Positive Airway Pressure ) assists in

improving TV• EPAP (Expiratory Positive Airway Pressure) helps to

recruit more alveoli / prevents closure of alveoli• Differential in pressure between inspiration and

expiration (PS ) allows for better patient- ventilator synchrony -> more comfort

Ventilators for NPPVPressure Limited Ventilators

• Pressure-limited ventilators. • Pressure-limited modes are available on most ventilators designed for use on intubated

patients in critical care units. • PSV – Pressure Support Ventilation - delivers a preset inspiratory pressure to assist

spontaneous breathing efforts ( assist weaning)• PCV- Pressure control ventilation (PCV) that delivers time-cycled preset inspiratory and

expiratory pressures with adjustable inpiratory:expiratory ratios at a controlled rate. • Most such modes also permit patient-triggering with selection of a backup rate.• Nomenclature for these modes varies between manufacturers, causing confusion.• For the pressure support mode, some ventilators require selection of a pressure

support level that is the amount of inspiratory assistance added to the preset expiratory pressure and is not affected by adjustments in PEEP.

• Others require selection of peak inspiratory and expiratory positive airway pressures (IPAP and EPAP), the difference between the two determining the level of pressure support. It is important to recall that with the latter configuration, alterations in EPAP without parallel changes in IPAP will alter the pressure support level.

PSV• What distinguishes PSV from other currently available ventilator

modes is the ability to vary inspiratory time breath by breath,

permitting close matching with the patient's spontaneous breathing pattern.

• A sensitive patient-initiated trigger signals the delivery of inspiratory pressure support, and a reduction in inspiratory flow causes the ventilator to cycle into expiration.

• In this way, PSV allows the patient to control not only breathing rate but also inspiratory duration.

• As shown in patients undergoing weaning from invasive mechanical ventilation , PSV offers the potential of excellent patient-ventilator synchrony, reduced diaphragmatic work, and improved patient comfort.

Multiple options and Modes• Use ICU ventilators• Use Special bilevel support Machines• Use home Ventilators

• Pressure limited Modes– Pressure supported Ventilation– Pressure Controlled Ventilation

• Volume limited Modes ( A/C , SIMV)• Time cycled

• Adjustable Trigger Sensitivity, Rise Time (time to reach peak pressure), Inspiratory Duration : to increase patient ventilator synchrony and comfort

• Backup Rates

The patient fights the machine ?!

• Pay attention to patient- ventilator Synchrony

Bi-level devices

• Limited Pressure generating capabilities (20-35 cm H2O)• Lack Oxygen blender• Lack sophisticated alarm or backup systems• Newer versions – suitable for acute care: sophisticated

alarm, graphic display, monitoring, oxygen blender• Ideal for home use: portability, convenience, low cost• Leak Compensation - able to vary and sustain inspiratory

airflow• Rebreathing – Single tube with passive exhalation valve

Volume – Limited Ventilators• Most critical care ventilators offer both pressure- and volume-limited modes, either of which can be

used for administration of noninvasive ventilation. • Volume-limited ventilators.

• Portable volume-limited ventilators : greater convenience and lower cost. • Applied just as for invasive ventilation, using standard tubing and exhalation valves, with oxygen

supplementation and humidification as necessary. • Compared with the portable pressure-limited ventilators, the volume-limited portable ventilators are

more expensive and heavier. • However, they also have more sophisticated alarm systems, the capability to generate higher positive

pressures, and built-in backup batteries that power the ventilator for at least a few hours in the event of power failure.

• These ventilators are usually set in the assist/control mode to allow for spontaneous patient triggering, and backup rate is usually set at slightly below the spontaneous patient breathing rate.

• The only important difference relative to invasive ventilation is that tidal volume is usually set higher (10 to 15 ml/kg) to compensate for air leaking.

• Currently available volume-limited ventilators are well suited for patients in need of continuous ventilatory support or those with severe chest wall deformity or obesity who need high inflation

pressures.

Newer noninvasive ventilator modes

• Because patient comfort and compliance with the therapy are so critical to the success of noninvasive ventilation, newer modes that are capable of closely mirroring the patient's desired breathing pattern are of great interest.

• One such new ventilator mode is proportional assist ventilation (PAV), which targets patient effort rather than pressure or volume .

• By instantaneously tracking patient inspiratory flow and its integral (volume) using an in-line pneumotachograph, this mode has the capability of responding rapidly to the patient's ventilatory effort.

• By adjusting the gain on the flow and volume signals, the operator is able to select the proportion of breathing work that is to be assisted.

Different types of interfaces• Upper left panel shows different sizes

of typical disposable nasal masks used for continuous positive airway pressure (CPAP) or noninvasive positive pressure ventilation (NPPV).

• Lower left panel shows nasal "pillows” with a chin strap used to reduce air leaks through the mouth.

• Upper right panel shows oronasal mask with four strap headgear system. Arrow shows "quick release" strap to be used if rapid removal (such as with vomiting) is desired.

• Lower right panel shows mouthpiece with lipseal .

Patient interfaces

Nasal Mask• More air leaks• Requires a cooperative patient who can keep

his/ her mouth closed• More comfortable for claustrophobic patients

Nasal Masks• Widely used, particularly for chronic application (CPAP or NPPV)• Triangular or cone shaped clear plastic device that fits over the nose and utilizes

a soft cuff to form an air-seal over the skin• Multiple sizes and shapes• The standard mask exerts pressure over the bridge of the nose, in order to

achieve an adequate air seal, often causing skin irritation and redness and occasionally ulceration

• Modifications to minimize this complication:– forehead spacers or – the addition of a thin plastic flap that permits air sealing withy less mask pressure on

the nose– Nasal masks with gel seals that may enhance comfort

• Minimasks ( reduce claustrophobia, allows to wear glasses • Custom molded individualized masks

Nasal Mask Ventilation

Straps

• Straps that hold the mask in place are also important for patient comfort.

• Many types of strap assemblies are available.

• Most manufacturers provide straps that are designed for use with a particular mask.

• Straps that attach at two or as many as five points on the mask have been used, depending on the interface.

• More points of attachment add to stability. • Strap systems with Velcro fasteners are popular• Elastic caps that help to keep the straps from tangling or

sliding have been well received by patients.

Nasal Pillows

• An alternative type of nasal interface, nasal "pillows" or "seals," consist of soft rubber or silicone pledgets that are inserted directly into the nostrils.

• Because they exert no pressure over the bridge of the nose, nasal pillows are useful in patients who develop redness or ulceration on the nasal bridge while using standard nasal masks.

• Also, some patients, particularly those with claustrophobia, prefer nasal pillows because they seem less bulky than standard nasal masks.

Patient Interfaces

Full Face mask• Delivers higher ventilation pressures without

leaks• Allows for mouth breathing• Requires less patient cooperation• Less comfortable , impairs speech

comprehensibility, may limit oral intake

Oronasal (full face) Masks

• Cover both the nose and mouth• Used in respiratory failure• Interference with speech, eating, expectoration• asphyxiation in patients who are unable to

remove the mask in the event of power failure or malfunction

• Claustrophobia• Rebreathing

Oronasal Masks

• Oronasal masks may be preferred for patients with copious air leaking through the mouth during nasal mask ventilation.

• Improvements in oronasal masks, such as more comfortable seals, improved air-sealing capabilities, and incorporation of quick-release straps and antiasphyxia valves to prevent rebreathing in the event of ventilator failure, have increased acceptability of these interfaces for chronic applications.

• The ”Total" face mask is made of clear plastic, it uses a soft cuff that seals around the perimeter of the face, avoiding direct pressure on facial structures.

Total face mask

Interface

Nasal Mask• Less claustrophobia• Less dead space• Allows for expectoration• Allows for oral intake• Vocalization

Facial Mask• Dyspneic patients –

usually mouth –breathers

• More dead space

Mask – Orofacial vs. NasalNASAL MASK OROFACIAL MASK

Improving Vital Signs and gas exchange

Similar Similar

Avoiding Intubation Similar Similar

Air Leak Greater, less well tolerated in mouth breathers

Less

The Helmet Interface

Helmet Vs. Facial Mask

• Complications (skin necrosis, gastric distension, and eye irritation) were fewer with helmet

• Allowed prolonged continuous application of NIV • Length of stay in ICU, Intubation rates, Mortality

similar

Humidification during NIV

• No humidification :– Dry mucosa– Increased airway resistance– Reduced compliance

• Heated humidification versus HME (heat and Moisture exchanger) – The jury is still out

• HME may reduce the efficacy of NIV/ increase WOB

Location of NIV

• DEM• ICU• Intermediate Care Unit• Medical Ward• Home

Advantages of NIV• NON INVASIVE TECHNIQUE

– Application (compared with ET intubation)• Easy to implement• Easy to remove• Intermittent application is feasible

– Improves patient comfort– Reduces the need for sedation– Oral Patency

• Preserved speech, swallowing and cough• Reduced need for NE Tubes

• Avoid the resistive work induced by ET tubes• Avoid the complications of ET intubation

– Early (local trauma, aspiration)– Late (injury to the the hypopharynx, larynx, and trachea, nosocomial infections

Disadavantages/ Complications of NIV

SYSTEM• Slower correction of gas exchange abnormalities• Increased initial time commitment• Gastric distention ( in less than 2% of patients)• Barotrauma

MASK• Air Leakage• Hypoxemia – due to accidental mask removal• Eye irritation• Facial skin necrosis ( the most common complication)• Clausrophobia• IrritationLACK OF AIRWAY ACCESS and PROTECTION• Suctioning of secretions• Aspiration

Who Needs NIV ?Clinical assessment of ARF

• Check Level of Consciousness

• Increased Work of Breathing

• Respiratory rate• Paradoxical abdominal

motion• Catecholamine drive : HR,

sweat etc• Need ABG-s to assess

hypercarbia

NIV – Patient Selection Criteria

• Patient selection Criteria:• pH < 7.35 with pCO2 > 45 mm Hg• Respiratory rate > 25 bpm• Respiratory distress with :– Moderate to severe dyspnea– Use of accessory muscles– Abdominal paradoxical motion

Kramer , Am J RCCM 1995; 151: 1799-1806

Initiating NIV

• Decide to initiate NIV• Select mode of Ventilatory Support• Use CPAP if the main problem is hypoxemia• Use BiPAP if the main problem is hypercarbia• Explain – what ‘s your plan• Hold the mask in place without securing it at first• Once synchrony is achieved, secure the mask with

straps• Avoid too tight fit

Initiation of Therapy

• CPAP : start at 5 cm H2O• BiPAP: start with IPAP of 8-10 cm H2O and EPAP

of 3-5 cm H2O• Increase these parameters gradually , usually by

2 cm H2O at a time , until an exhaled tidal Volume (TV) of 5-10 ml/ kg is achieved and Respiratory Rate falls below 25 bpm

• Adjust EPAP (PEEP) for hypoxemia• Monitor SpO2 , heart rate, respiratory rate

Modes• Spontaneous/ Timed (S/T)• Increases pressure when the patient breathes in and decreases pressure when the

patient exhales. • Machine will trigger a breathe if the patient does not breathe within a preset time.• Spontaneous (S) • As above but there is no automatic delivery of breath if the patient fails to inhale. • Timed (T) • The machine controls both inhalation and exhalation independent of spontaneous

breathing. • Pressure Control (PC)

• Average Volume Assured Pressure Support (AVAPS) • Auto adjusts to provide a constant tidal (lung) volume.• Continuous Positive Airway Pressure (CPAP).

Initiation of TherapyMonitoring

Adequate monitoring includes :• Vital signs• Cardiac Monitoring• Pulse Oximetry

Perform Serial clinical assessment RE:• Patient comfort with machine• Mental Status• Work of Breathing• Handling of secretions

• Use ABG-s to assess adequacy of treatment periodically

MonitoringNeed to monitor response• Physiological

– Continuous oxymetery– Exhaled Tidal Volume– Obtain ABG-s within an hour and

q 2-6 h or as needed

• Objective– Respiratory Rate– Blood Pressure– Pulse Rate

• Subjective– Dyspnea– Mental alertness– Comfort

MASK• Fit, Comfort, Air leak,

Skin Necrosis, SecretionsRESPIRATORY MUSCLE

UNLOADING• Accessory muscle

activity• Paradoxical abdominal

motion

ABDOMEN• Gastric Distention

The First Hour

• Titrate settings and FIO2• Adjust to reduce work of breathing and Respiratory

Rate• Assist patient comfort and tolerate mask• Use minimal sedation if needed (i.e. MO 2 mg or Halidol

2 mg)• Monitor Mental Status• If worsening : INTUBATE• Keep patient NPO initially• Check ABG-s in 1 -2 hours

Initial Assessment

In Patients who benefit from NIV :• Improvement of the dyspnea• Improvement of signs of respiratory failure• These changes may occur within an hour after

initiation of NIV• A Rapid decrease in Respiratory Rate is an

excellent indicator of successful Rx.• Follow : level of consciousness, SpO2 and ABG-s

Indicators of likelihood of NIV success

• Younger Age• Good dentition• Lower Acuity of illness• Normal mental status• Ability to cooperate• Less air leak• Moderate hypercarbia (46-91 mm Hg) • Moderate acidemia (pH 7.11 – 7.34)• Improvements of gas exchange and vital signs within 2 hours• Coma has been considered a contraindication , but a study observed

a high success rate of NIV in patients with hypercarbic comaGonzales Diaz et al Chest 2005; 127: 952-960

Indicators of NIV Failure

• Patient’s intolerance for NIV• Failure to improve after 1-2 hours • Progressive confusion • Inability to handle secretions• Chest pain ( look out for ischemia/ MI)• Arrhythmia• Apnea

Who should not be considered for NIV ?

• Contraindications:TOO SICK CAN’T PROTECT AIRWAYSCardiac arrest Severe UGI bleeding

Respiratory arrest Facial trauma/ neurosurgery

Non Respiratory organ failure Upper airway obstruction

Hemodynamic Instability Inability to cooperate

Acute MI Inability to protect airways

Severe Encephalopathy High risk for aspiration

Severe Sepsis Excess secretions

NIV for Acute Respiratory Failure

• Multiple applications• Only four supported by multiple RCT-s and

meta- analyses:• COPD exacerbation• Acute Cardiogenic Pulmonary Edema• Facilitating extubation in COPD patients• Immunocompromised patients

Uses of NIV

• COPD – acute exacerbation• COPD – home • Cardiogenic Pulmonary Edema• Acute Asthma• Post extubation RF• Neuromuscular disorders

• Hypoxemic acute respiratory failure (mixed results)• Obesity and ARF• In “do – not intubate” patients

Acute exacerbation of COPD

• Morbidity and Mortality mainly in mechanically ventilated patients

• 20% - difficult to wean off the ventilation• Up to 20% of patients with COPD exacerbation

are candidates for NIV

Kramer N, Am J RCCM 1995; 151;1799-1806

NIVIn COPD exacerbation

• Success rates of 80-85%• In the first 4 hours of treatment• Increases pH• Reduces pCO2• Reduces the severity of dyspnea• Shortened length of hospital stay • Reduced intubation rate• Reduced Mortality----------------------------------------------------------------------------------• The lower the pH the higher the likelihood for ET intubation

NIV in Acute Respiratory Failure

Kramer et al, Am J Respir Crit Care Med 1995; 151: 1799-806

0 1 2 3 6 12 24 48 72

0

20

40

60

80

Control 12 (8) 67%

NPPV 11 (1) 9%**

Time in Hours

% COPD Patients Needing

Intubation

* p < 0.05

NIV versus standard care in COPD exacerbation (236 pts.)

NIV results in:• faster pH correction at 1 h, • faster correction of RR at 4 h, • trend for pO2 improvement at 4 h• Breathlessness – relieved faster with NIV• NIV use results in decrease of intubation rates from 74

to 25% and mortality rates• NIV resulted in a reduction of LOS and complication

rate Plant PK, Lancet 2000; 355: 1931-1935

Extubation in COPD patients

• In candidates who failed a T-Tube trial event though they improved consider extubation and a NIV trial

• Studies observed shorter durations of intubation and ICU stays , decreased incidence of nosocomial pneumonia and improved ICU and 90 day survival

Ferrer M, Am J RCCM 2003; 168: 70-76

Acute Pulmonary Edema• Strong evidence supports the use of NIPPV to treat acute Cardiogenic

Pulmonary edema• The need for ETI was reduced from 35% to 0% by the use of CPAP• A study comparing the use of CPAP, BiPAP and historical controls

indicated a higher rate of Acute MI in the BiPAP group (31% CPAP, 71% BiPAP and 38% control ( 13 pts with CPAP 10 cmH2, 14 with bilevel 15/5 cm

• Bilevel improved more rapidlyMehta S , CCM 1997; 25: 620-628

• Until this issue is clarified – prefer CPAP mode of NIV in this groupNava S , Am J RCCM 2003; 168: 1432- 1437

• Exception : Hypercapnic Cardiogenic Pulmonary Edema

MethodologyCPAP or BiPAP in CPE

• Initial ventilator settings: CPAP (EPAP) 2 cm H2O & PSV (IPAP) 5 cm H20.

• Mask is held gently on patient’s face.• Increase the pressures until adequate Vt

(7ml/kg), RR<25/mt, and patient comfortable.• Titrate FiO2 to achieve SpO2>90%.• Keep peak pressure <25-30 cm• Elevate Head of the bed

What is NIV ?

• A technique looking for indication ?

• The best thing under the sky for those who need ventilatory assistance ?

--------------------------------------Not a “panacea” !Nor is it a “poor man’s technique

Criteria to discontinue NonInvasive Ventilation

• Inability to tolerate the mask because of discomfort or pain

• Inability to improve gas exchange or dyspnea• Need for endotracheal intubation to manage

secretions or protect airway• Hemodynamic instability• ECG – ischemia/arrhythmia• Failure to improve mental status in those with

CO2 narcosis.

Conclusions

• After initiation of NIV – plan how to recognize a treatment failure and what to do for the failing patient

• No convincing evidence that a failed NIV trail is harmful

• NIV should be viewed as a preventive measure rather than an alternative to mechanical ventilation via ET .

Remember

• First 30 minutes of NIV is labor intensive• Presence of skilled personnel, familiar with

this mode at bedside is essential• Provide reassurance, adequate explanation• Be ready to intubate and mechanically

ventilate if the non invasive approach fails

On the role of non-invasive ventilation (NIV) to treat patients during the H1N1 influenza pandemicGiorgio Conti*,MD, Anders Larrsson° Stefano Nava+ MD, , Paolo Navalesi&, MD MDsc, DEAAFrom: * Pediatric Intensive Care Unit, Catholic University School of Medicine, Rome, Italy ° , Anesthesiology and Intensive Care Medicine Uppsala University Sweden+Respiratory Intensive Care Unit, Fondazione S.Maugeri, Pavia, Italy, &Intensive Care Unit, University Hospital Maggiore della Carità, Eastern Piedmont University, Novara, ItalyCorrespondence address: Stefano Nava, MD Respiratory Intensive Care Unit Fondazione S.MaugeriVia Maugeri n.10 27100 Pavia, Italy phone 0382 592806 e-mail: stefano.nava@fsm.it

Thank you

EXTRAS

NIV in Hypoxemic ARF

• 62% improved O2 in 1 hour• 30% required ET in the NIV group• Higher mortality in ET group (47%) than in NIV

group (28%)• LOS 16 days vs. 9 days• Complication rate 66% vs. 38%• 29 studies with 748 patients with hypoxemic

ARF of various etiology – mixed results

Immunocompromised patientsHilbert:NEJM:2001:344:481

• Immunosuppressed patients with fever/ARF and CXR infiltrates: RCT in Canada

• 52 patients with Neutropenia, transplant, hematological malignancies or chemo

• Method: NIV for 45 minutes every 3 hours for 24 hrs

• RESULTS:

•

NIV ControlETI 46%

(12/26)77% (20/26)

ICU mortality 38% 69%

In Hospital Mortality

38% 81%

Immunocompromised patients

• The use of NIV should be considered in immunocompromised patients at high risk for infectious complications from ETI , i.e. hematologic malignancies AIDS, following solid organ transplant or BMT

• In a randomized trial of patients with hypoxemic respiratory failure following solid organ transpantation, the use of NIV decreased intubation rate (20% versus 70% p< 0.002 and ICU mortality (20% versus 50%, p=0.005) compared with conventional therapy with O2

Antonelli M, JAMA 2000; 283: 2239-2240

NIV in Asthma

• No randomized controlled studies• Several reports of successful treatment• High success rate• Think of Heliox

NIV in post extubation ARF• 97 patients post extubation RCT with high risk pts: CHF, previous failure,

comorbid condition, weak cough, increase pCO2– NIV >8h /day for 48 hrs vs. standard care – NIV group had 12% lower mortality, 16% lower reintubation

rate and LOS– Reintubation was associated with 60% increase mortality in ICU– CONCLUSION : USEFUL MODALITY IN SELECT HIGH RISK

PATIENTS

Nava. CCM 2005:33:2465

NIV in Obesity and ARF

• ARF in 50 obese patients: BMI 53 +/- 12• 60% had OSA• All had baseline CO2 retention

• Hemodynamic stable patients • Acute hypercapnia• RESULTS:

• 17 patients ETI• 33 patients with NIV:21 avoided ETI• NIV success patients : no deaths• ETI patients 31% mortality (9/21)

Duarte : CCM 2007: 35:732

How to deliver aerosol nebulization in a patient receiving NIV?

• Desirable – without removing NIV• Aerosol delivery when the leak port is in the

mask or with a leak port of different design?

Types of ARF Treated with NIVDiagnosis for Acute Respiratory failure• Obstructive Airway Diseases• COPD• Asthma• Cystic Fibrosis• Upper airway Obstruction• Restrictive Diseases• Chest wall deformity• Neuromuscular Diseases• Obesity Hypoventilation• Parenchymal Diseases• AIDS related Pneumonia• ARDS• Infectious Pneumonia• Cardiogenic• Acute Pulmonary Edema (CPAP)

Selection Guidelines : NIV for patients with COPD and ARF

• Identify Patients in need of ventilatory assistance

• Symptoms and signs of ARF• Moderate to severe dyspnea

, increased over the usual• RR > 24, accessory muscle

use, paradoxic breathing• Gas exchange abnormalities• pCO2 > 45 mm Hg, pH <

7.35 or• paO2/FIO2 < 200

• Exclude those with increased risk from NIV

• Respiratory arrest• Medically unstable: hypotensive

shock, arrhythmias, uncontrolled cardiac ischemia

• Unable to protect airway (impared cough or swallowing)

• Excessive secretions• Agitated or uncooperative• Facial Trauma, burns or surgery

or anatomic abnormalities interfering with mask fit

Success Predictors during acute applications of NIV

• Younger age• Lower acuity of illness (APACHE score)• Able to cooperate; better neurologic score• Able to coordinate breathing with ventilator• Less air leaking, intact dentition• Hypercarbia, but not too severe (PaCO2 > 45 mm

Hg, < 92 mm Hg)• Acidemia, but not too severe (pH < 7.35, > 7.10)• Improvements in gas exchange and heart and

respiratory rates within first 2 h

TroubleshootingEur Resp J 2002; 20:

Problem Potential cause Corrective measure

Inspiratory trigger failure Air LeakAutocyclingIncreased WOB

Adjust mask or change typeReduce trigger sensitivityAdjust trigger sensitivity or change to a flow trigger if pressure trigger is used

Inadequate pressurization Pressure rise time too longPressure support too low

Reduction of pressure rise time. Increase Inspiratory Pressure

Failure to cycle into expiration Air leak leading to “Inspiratory hang –up”High end inspiratory flow

Adjust mask or consider switching from nasal to face mask. Increase end inspiratory flow threshold and set time limit for inspiration

CO2 rebreathing Single circuit with no true exhalation valveHigh Respiratory RateNo PEEPLarge Mask Dead space

Use 2 lines and use nonrebreathe valveLower Respiratory rateAdd PEEP to Lavage maskReduce Dead space with padding

The essentials of Critical Care Medicine

• BLOOD GOES ROUND AND ROUND• AIR GOES IN AND OUT• OXYGEN IS GOOD!