NIPPV

BY Dr Irappa Madabhavi

NON INVASIVE VENTILATION

DR IRAPPA MADABHAVI

DIFFERENT INDICATIONS

Carlucci et al, AJRCCM, 2001

INCREASING IMPORTANCE OF NIV

WHY THE INTEREST IN NIV?• It avoids the need for endotracheal

intubation/sedation/NMB• It reduces the occurrence of complications such

as Nosocomial infection and tracheal stenosis• It decreases intensive care unit (ICU) stay and

overall cost of hospitalization in selected patients• Achieves alveolar ventilation and gas exchange

parameters similar to IMV• Permits removal of secretions, eating and speechBrochard L, Mancebo J, Elliott MW.

Noninvasive ventilation for acute respiratory failure. Eur Respir J 2002;19(4):712-721.

DEFINITION OF NIV• Noninvasive ventilation is the delivery of

ventilatory support without the need for an invasive artificial airway (an endotracheal or tracheostomy tube)

• NPPV typically is administered through a nasal or an oral mask

ARFC Consensus Conference: non-invasive positive pressure ventilation: consensus statement, Respir Care 42:362, 1997

Types of Noninvasive Ventilation (NIV)

• Negative Pressure Ventilation (NPV)

• Noninvasive Positive Pressure Ventilation (NPPV)

Negative Pressure Ventilation (NPV)

• Iron lung/tank ventilator• Cuirass• Pneumojacket /pneumosuit

Iron lung constructed 1950

Continuous Positive Airway Pressure (CPAP)

• Provides a constant pressure, but no ventilatory support. So CPAP is not considered as a form of ventilation

• More effective in hypoxemic than in hypercapnic states. • It requires a spontaneously breathing patient and is unable

to support in the case of apnea.• Improves alveolar edema and increases functional residual

capacity• Main uses are:

OSA pt Congestive heart failure

Am J Respir Crit Care Med 2001;163: 283–291

• Both pressure-cycled and volume-cycled modes are available.

• Pressure-cycled ventilation is the preferred mode. In this mode, a preset pressure is applied with inspiration and expiration known as IPAP and EPAP

Noninvasive Positive Pressure Ventilation

IPAP – Inspiratory positive airway pressure

• Reduces the work of breathing – Alleviates respiratory distress – Unloads respiratory muscles – Improves respiratory muscle function Augments alveolar ventilation Reduces dead space ventilation Reduces rate related auto PEEP dynamic

hyperinflation• Improves gas exchange: hypoxemia and hypercapnia

Antonelli M et al, Crit Care 2000

EPAP – Expiratory positive airway pressure

• Improves gas exchange: by alveolar recruitment and corrects hypoxemia

• Increases FRC by preventing end exp collapse• Improves respiratory muscle fn : reduces dynamic

hyperinflation advantage to the diaphragm and intercostals

• Auto PEEP (Inspiratory threshold load) : Offsets intrinsic PEEP, aids triggering

• Reduces re-breathing • Enhances the delivery of bronchodilators to distal

bronchial tree

DIFFERENT MODES

• Continuous positive airway pressure• Pressure support ventilation( IPAP alone)• Bilevel positive airway pressure: BiPAP (IPAP+

EPAP)• Proportional assist ventilation(PAV)• Assist-controlled ventilation (mask IPPV)

Craig TH, Emerg Med 2002Mehta Set al, AJRCCM 2001

CHOICE OF INTERFACES• Currently available interfaces include nasal,

oronasal and facial masks, mouthpieces and helmets.

• For treatment of acute respiratory failure, facial masks are most commonly used (70% of cases), followed by nasal masks (25%) and nasal pillows (5%)

NASAL MASKS• More air leakage through the mouth so fail to

deliver air pressures to the lungs reliably• Better tolerance, less claustrophobia• Small dead space (104 ml vs. 250 ml facial mask)• Better ability to vocalize, expectorate, eat and

drink• Resistance of the nasal passages. Limited

effectiveness when the nasal resistance exceeds 5 cm H2O/L per second

ORO NASAL MASKS OR FULL FACE MASKS

• It permits mouth breathing and reduce air leaks through the mouth

• They may be preferred by acutely dyspneic patients who are “mouth breathers.”

• They interfere more with speech, eating, and expectoration and may contribute more to claustrophobic reactions and dead space than nasal masks.

Crit Care Med 2003 Vol. 31, No. 2,468-473

VARIOUS INTERFACES

Crit Care Med 2009; 37:124 –131

A face mask should be the first-line strategy in the initial management of hypercapnic acute respiratory failure with NIPPV. However, if NIPPV has to be prolonged, switching to a nasal mask may improve comfort by reducing face mask complications.

nasal mask group

face mask group

HUMIDIFICATIONS MOUTH LEAK Unidirectional inspiratory nasal airflow DRYING OF NASAL MUCOSA RELEASE OF INFLAMM. MEDIATOR INCREASE NASAL RESISTANCE

Different types include heated or unheated Passover devices, pass through devices, and HME, however with pressure-targeted ventilators only pass-over humidifiers should be applied, since pass through devices, and HME may compromise pressure andflow delivery and triggering.

EVIDENCE BASED GUIDELINES:

INDICATION OF NIV

INDICATIONS FOR ACUTE NON-INVASIVE VENTILATION

Recommended: first choice for ventilatory support in selected patients. Guideline: can be used in appropriate patients, but careful monitoring is advised.Option: suitable for a very carefully selected and monitored minority of patients.b Best evidence for severe COPD with pH < 7.35.c In most recent review, no evidence of survival benefit

INDICATIONS FOR ACUTE NON-INVASIVE VENTILATION

INDICATIONS FOR ACUTE NON-INVASIVE VENTILATION

Ambrosino N, Vagheggini G. Noninvasive positive pressure ventilation in the acute care setting : where are we? Eur Respir J 2008;31:874–886; and Hill NS, Brennan J, Garpestad E, Nava S. Noninvasive ventilation in acute respiratory failure . Cri t Care Med 2007; 35:2402–2407

NIPPV AND AE-COPD• NPPV has been proposed as the first-line

ventilatory strategy for treatment of acute-on-chronic respiratory failure due to AECOPD.

Non invasive positive pressure ventilation to treat respiratory failure resulting from AE-COPD Cochrane systematic review and meta analysis

What studies showed?• A lower mortality rate (RR 0.41;95% CI 0.26–0.64)• Less need for endotracheal intubation(RR 0.42;

95% CI 0.31–0.59)• A lower rate of treatment failure (RR0.51; 95% CI

0.38–0.67)• Greater improvements in the 1-hour post

treatment pH and PaCO2 levels• A lower respiratory rate• A shorter length of stay in the hospital

Lightowler JV, Wedzicha JA, Elliott MW, Ram FS. Cochrane systematicreview and meta-analysis. BMJ 2003; 326:185.

USE OF NIPPV AND DIFFERENT SEVERITY OF ARF

Eur Respir J 2008; 31: 874–886

WHEN TO START NIPPV?

NIV in COPD. ERS School in Pisa

IDENTIFICATION OF PATIENT SUB GROUP IN AE-COPD

Ann Intern Med. 2003;138:861-870

This meta-analysis of 15 trials found that adding NPPV to standard care reduced rates of endotracheal intubation, length of hospital stay, and in-hospital mortality rates in patients with AE-COPD

SUB-GROUP ANALYSIS

Selection Guidelines for NIV in theAcute Setting

• Appropriate diagnosis with potential reversibility• Establish need for ventilatory assistance Moderate-to-severe respiratory distress Tachypnea (respiratory rate > 24/min for COPD, 30/min for CHF) Accessory muscle use or abdominal paradox Blood gas derangement (pH <7.35, Paco2 > 45 mm Hg, or Pao2/Fio2 <200)

Do not use this therapy if the patient Has

• Respiratory arrest• Is medically unstable (hypotensive shock, uncontrolled

cardiac ischemia or arrhythmias)• Cannot protect the airway (impaired cough or swallowing

mechanism)• Has excessive secretions• Is agitated or uncooperative• Has facial trauma, burns, or surgery, or anatomic

abnormalities interfering with mask fit• Has an Acute Physiology and Chronic Health Evaluation

(APACHE) score > 29RESPIR CARE 1997; 42:364–369EUR RESPIR J 2005; 25:348–355; THORAX 2002; 57:192–211.

Predicting NIV Failure in COPD: Chart of Failure (baseline and 2 hrs)

MODE OF ACTIONS

EFFECT OF NIPPV ON WOB

CONSEQUENCES OF AUTO-PEEP• Increases the work of breathing• Worsens gas exchange• Can cause hemodynamic compromise . Reduces the preload of the right and left ventricles, decreases LV

compliance and can increase RV after load by increasing PVR.

Can lead to inappropriate treatment Misinterpretation of CVP AND PCWP measurements Erroneous calculations of static respiratory compliance: The true value of static compliance will be underestimated Inappropriate fluid administration or unnecessary vasopressor therapy

Auto-positive end-expiratory pressure:Mechanisms and treatment

CLEVELAND CLINIC JOURNAL OF MEDICINE

ACPEACUTE CARDIOGENIC PULMONARY EDEMA

CARDIOGENIC PULMONARY EDEMACARDIOGENIC PULMONARY EDEMA

N Engl J Med 2008;359:142-51.

The 3CPO Trial

Primary Outcome: Mortality Standard Oxygen Therapy versus Non-invasive Ventilation

1.0

0.9

0.8

0 10 20 30

Days

CumulativeSurvival

StandardOxygen Therapy

Non-invasiveVentilation

P=0.685

OUTCOME OF 3CPO Trial

• CPAP or NIPPV was significantly better than standard oxygen therapy in the first hour of treatment in terms of the

Dyspnea score Heart rate Acidosis Hypercapnia. However, there were no significant differences between

groups in the 7- or 30-day mortality rates, the rates of intubation, rates of admission to the critical care unit, or in the mean length of hospital stay.

• NIV and CPAP equally and safely improve vital signs and gas exchange

• To date, no trial has been sufficiently powered to confirm a mortality benefit from either technique.

• At this time we cannot conclude that NIV offers any advantages over CPAP.

CARDIOGENIC PULMONARY EDEMA

Potential Mechanisms of Action of CPAP and NIV in Patients With Acute CPE

• CPAP

Increased functional residual capacity Reduced atelectasis Reduced right-to-left intrapulmonary shunt Reduced work of breathing from improved pulmonary

compliance Increased cardiac output from reduced pre-load and after-load Reduced mitral regurgitation• NIV Same benefits as CPAP Unloads the respiratory musclesRespir Care 2009;54(2):186 –195

Anesthesiology 2005; 103:419–28

Causes significant decrease in the heart ratedue to parasympathetic tone (by CPAP inducedlung inflation)

DIASTOLIC HEART FAILURE

• CPAP improves oxygenation and ventilatory parameters in all kinds of CPE.

• In patients with preserved LV contractility, the hemodynamic benefit of CPAP results from a decrease in LV end-diastolic volume (preload)

• CPAP, by decreasing respiratory work in patients with cardiopulmonary edema, unloads the heart from the large amount of cardiac output that supplies the respiratory muscles and improves oxygen delivery for other tissues.

Chest 2005; 127:1053–1058

WHEN TO USE NIV IN ACPE?

• GRAY ET AL noninvasive ventilation (CPAP or NIPPV) be considered as “adjunctive therapy” in patients with acute cardiogenic pulmonary edema who have severe respiratory distress or whose condition does not improve with pharmacologic therapy

Start with CPAP•If persisting dyspnea or hypercapnia with CPAP alone, add pressure support

RCTs have found decreased intubationshorter ICU lengths of stay and Decreased ICU mortality rates

The reduced mortality is likely related to reduced infectious complications associated with NIV use VAP, other nosocomial infections, and septic shock

Antonelli et al JAMA 2000; 283:235Hilbert G, et al: N Engl J Med 2001; 344: 481

Respiratory Failure in Immunocompromised Patients

NIV is recommended as first choice treatment

Am J Respir Crit Care Med Vol 168. pp 70–76, 2003

Intubated patients who met criteria to proceed in the weaningattempt but had failed a spontaneous breathing trial for 3 consecutive days were considered eligible for the study

Noninvasive Ventilation during Persistent Weaning FailureA Randomized Controlled TrialMiquel Ferrer at al Am J Respir Crit Care Med Vol 168. pp 1438–1444, 2003

NIVNIV

Am J Respir Crit Care Med Vol 168. pp 70–76, 2003

SERIOUS COMPLICATIONS

MECHANISMS OF IMPROVEMENT

• Because patients with unsuccessful weaning are likely to develop a rapid and shallow breathing pattern, the ability of NIV to improve hypoxemia and hypercapnia by correcting such an abnormal breathing pattern might explain the benefits of NIV in these patients

• Decrease period on MV will reduce the complications associated with it

OUTCOME Earlier extubation with NIV

results in shorter • Mechanical ventilation • length of stay• less need for tracheotomy• lower incidence of complications,

and improved survival

HYPOXAEMIC RESPIRATORY FAILURE

• Several diseases may lead to hypoxaemic ARF which is defined by a PaO2/FIO2 ratio ≤300 mmHg

• Result is conflicting due to heterogeneous group of clinical conditions, ARDS, pneumonia and thoracic trauma.

NIV in Acute Hypoxemic Respiratory Failure

Respir Care 2009;54(12):1679 –1687

RECOMMENDATIONS IN DIFFERENT SUBGROUPS

Crit Care Med 2007; 35:2402–2407

• NIV cannot be recommended as routine therapy for ALI/ARDS

• A cautious trial in highly selected patients with a Simplified Acute Physiology Score II ≤34 and readiness to promptly intubate if oxygenation fails to improve sufficiently within the first hour.

• Trial should always be done in ICU

RECOMMENDATIONS IN DIFFERENT SUBGROUPS

Predictors for failure in hypoxaemic respiratory failure

• No or minimum rise in the ratio of PaO2/FIO2 after 1–2 h

• Patients older than 40 years (one study)• Simplified acute physiology score >34 at

admission • Presence of ARDS• CAP with or without sepsis, and multiorgan

system failure

Intensive Care Med 2001; 27:1718–1728.

NIV IN ASTHMA• According to the British Thoracic Society

Standards of Care Committee Statements:• ‘‘NPPV should not be used routinely in acute

asthma, but a trial might be considered in patients not promptly responding to standard treatments’

POST OPERATIVE RESPIRATORY FAILURE

• Respiratory insufficiency in patients undergoing major surgery, especially of the chest or upper abdomen, is relatively common.

• After abdominal surgery, respiratory complications occur in approximately 10% of patients, and reintubation represents 30% of those complications.

• Pain, splinting, and respiratory muscle dysfunction, atelectasis are likely contributors to hypoxemia and respiratory insufficiency.

POST OPERATIVE RESPIRATORY FAILURE: prevention and treatment

Anesthesiology 2010; 112:453– 61

MECHANISMS OF IMPROVEMENT

Although multiple studies support this application, further studies need to focus on the use of NIV following specific surgical procedures before firmer recommendations can be made

Portable vs critical care ventilators

Liesching T et al , Chest 2003

Critical care versus portable ventilators

• The elaborate alarms may be counter-productive since they frequently indicate very minor air leaks that are common during NIV and not of clinical significance

• Use of single limb circuits in the portable devices, which may have an effect upon CO2 elimination

• While home ventilators can adequately compensate large gas leaks, ICU ventilators are not able to cope with large leaks

Eur Respir J 2002; 20: 1029–1036

COMPLICATIONS• Masks- pressure ulceration on the bridge of

the nose or above the ears (due to mask straps/headgear).

• Conjunctival irritation may be associated with air leak around the mask.

• Nasal congestion, oral or nasal dryness and insufflation of air into the stomach.

• Claustrophobia

COMPLICATIONS

• More serious complications include aspiration pneumonia, haemodynamic compromise associated with increased intrathoracic pressures and pneumothorax.

• The occurrence of each of these more serious complications, however, has been identified as less than 5% (Hill 2006).

• Significant air leak for most bi level devices is 0.4L/sec above intentional leak

• Decreased effectiveness of ventilation (NIPSV)– Inability to maintain optimal pressures (CPAP)– Sleep fragmentation– Inability to trigger ventilator– Prolonged inspiratory time– Greater oxygen requirement

COMPLICATIONS

Leak Monitoring in Noninvasive VentilationArch Bronconeumol 2004;40(11):508-17

EXTUBATION FAILURE• USE OF NIV routinely after extubation for

reducing extubation failure not recommended• Can be recommended in high risk patients

after extubation Age>65 APACHEII>12 at the time of ext. Cardiac failure at the time of intub.KHILNANI ET AL, IJCCM,2006GUIDELINES FOR NIV IN ARF

PREDICTORS OF FAILURE

b likelihood of failure 50% if any 3 and 82% if all 4 present at baseline;75% if any three and 99% if all four present after 2 hrs of NIV.

Ambrosino Thorax ’94Confalonieri, Rana, Antonelli ICM 2001, Antonelli ,CCM 2006

WEANING METHODS

• SBT after 48hrs stabilization on MV• FAIL SBT>STABILIZE WITH FULL MV SUPPORT

FOR 1 HR> EXTUBATE AND PUT ON NIV

GUIDELINES FOR NIV IN ARF IJCCM,2006