Indications

Definition

NoninvasiveventilationVentilationThe total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Ventilation: Mechanics of Breathing (NIV) is respiratory support that does not require an artificial, invasiveairwayAirwayABCDE Assessment (such as an endotracheal tube).

Types

• Noninvasivepositive pressure ventilationPositive pressure ventilationApplication of positive pressure to the inspiratory phase when the patient has an artificial airway in place and is connected to a ventilator.Flail Chest (NIPPV):
  • Can be provided with:
    • Continuous positiveairwayAirwayABCDE Assessment pressure (CPAP) 
    • Bilevel positiveairwayAirwayABCDE Assessment pressure (BiPAP).
  • Typically applied with a sealed face mask that covers both thenoseNoseThe nose is the human body’s primary organ of smell and functions as part of the upper respiratory system. The nose may be best known for inhaling oxygen and exhaling carbon dioxide, but it also contributes to other important functions, such as tasting. The anatomy of the nose can be divided into the external nose and the nasal cavity.Nose Anatomy (External & Internal) and the mouth. 
  • Can also be used in the form of a helmet
  • PositiveairwayAirwayABCDE Assessment pressure allows alveolarrecruitmentRecruitmentSkeletal Muscle Contraction to participate in oxygenation. 
• High-flownasal cannulaNasal CannulaRespiratory Failure (HFNC):
  • Another form of NIV that uses high concentrations of oxygen, which may be delivered at up to 60 L/min via large-borenasal cannulaNasal CannulaRespiratory Failure
  • At higherflowFlowBlood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls.Vascular Resistance, Flow, and Mean Arterial Pressure rates, HFNC generatespositive end-expiratory pressurePositive end-expiratory pressurePressure remaining in the distal airways of the patient at the end of expirationInvasive Mechanical Ventilation (PEEPPEEPPressure remaining in the distal airways of the patient at the end of expirationInvasive Mechanical Ventilation) above the physiologic level.

Indications

The most common indication for use is acuterespiratory failureRespiratory failureRespiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two.Respiratory Failure:

• Ideally, for consciouspatientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship with spontaneous breathing 
• Moderate to severehypoxemiaHypoxemiaNeonatal Respiratory Distress Syndrome orhypercapniaHypercapniaA clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.Neonatal Respiratory Distress Syndrome
• Increased respiratory effort andtachypneaTachypneaIncreased respiratory rate.Pulmonary Examination:
  • Accessory muscle use, pursed-lip breathing
  • Goal is to preventfatigueFatigueThe state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli.Fibromyalgia.

Common conditions that may be suitable for NIV:

• Acute hypoxicrespiratory failureRespiratory failureRespiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two.Respiratory Failure:
  • Infection/pneumoniaPneumoniaPneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy.Pneumonia
  • AsthmaAsthmaAsthma is a chronic inflammatory respiratory condition characterized by bronchial hyperresponsiveness and airflow obstruction. The disease is believed to result from the complex interaction of host and environmental factors that increase disease predisposition, with inflammation causing symptoms and structural changes. Patients typically present with wheezing, cough, and dyspnea.Asthma exacerbation
  • Pulmonary embolismPulmonary EmbolismPulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs.Pulmonary Embolism
  • AtelectasisAtelectasisAtelectasis is the partial or complete collapse of a part of the lung. Atelectasis is almost always a secondary phenomenon from conditions causing bronchial obstruction, external compression, surfactant deficiency, or scarring.Atelectasis
  • Posttrauma
• Acutehypercapnic respiratory failureHypercapnic Respiratory FailureRespiratory Failure +/– acute hypoxicrespiratory failureRespiratory failureRespiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two.Respiratory Failure:
  • AsthmaAsthmaAsthma is a chronic inflammatory respiratory condition characterized by bronchial hyperresponsiveness and airflow obstruction. The disease is believed to result from the complex interaction of host and environmental factors that increase disease predisposition, with inflammation causing symptoms and structural changes. Patients typically present with wheezing, cough, and dyspnea.Asthma or chronic obstructivepulmonary diseasePulmonary diseaseDiseases involving the respiratory system.Blastomyces/Blastomycosis (COPDCOPDChronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough.Chronic Obstructive Pulmonary Disease (COPD)) exacerbation
  • Heart failureHeart FailureA heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction.Total Anomalous Pulmonary Venous Return (TAPVR) (HF) exacerbation/pulmonary edemaPulmonary edemaPulmonary edema is a condition caused by excess fluid within the lung parenchyma and alveoli as a consequence of a disease process. Based on etiology, pulmonary edema is classified as cardiogenic or noncardiogenic. Patients may present with progressive dyspnea, orthopnea, cough, or respiratory failure.Pulmonary Edema
  • Hypoventilation from sedation
  • Progressiveobesity hypoventilation syndromeObesity hypoventilation syndromeHypoventilation syndrome in very obese persons with excessive adipose tissue around the abdomen and diaphragm. It is characterized by diminished to absent ventilatory chemoresponsiveness; chronic hypoxia; hypercapnia; polycythemia; and long periods of sleep during day and night (hypersomnolence). It is a condition often related to obstructive sleep apnea but can occur separately.Obstructive Sleep Apnea
  • Progressive neuromuscular disorder
• Note: Studies have shown amortalityMortalityAll deaths reported in a given population.Measures of Health Status benefit of NIPPV inCOPDCOPDChronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough.Chronic Obstructive Pulmonary Disease (COPD) and HF exacerbations.

Contraindications

While NIV may reduce the need forinvasive mechanical ventilationInvasive mechanical ventilationInvasive mechanical ventilation (IMV) is an advanced airway modality used for individuals with immediate or impending respiratory failure and/or in preparation for surgery. The IMV technique involves positive pressure ventilation delivered to the lungs through an endotracheal tube via a ventilator.Invasive Mechanical Ventilation and its associated complications, careful consideration for patientselectionSelectionLymphocyte activation by a specific antigen thus triggering clonal expansion of lymphocytes already capable of mounting an immune response to the antigen.B cells: Types and Functions is essential to prevent harm. 

Common contraindications for NIPPV include:

• Cardiac or respiratory arrest
• PoorairwayAirwayABCDE Assessment protection:
  • Increased secretions
  • Impaired coughing/swallowingSwallowingThe act of taking solids and liquids into the gastrointestinal tract through the mouth and throat.Gastrointestinal Motility
  • Altered mental statusAltered Mental StatusSepsis in Children
• UpperairwayAirwayABCDE Assessment trauma/anatomical abnormality
• UnstablehemodynamicsHemodynamicsThe movement and the forces involved in the movement of the blood through the cardiovascular system.Vascular Resistance, Flow, and Mean Arterial Pressure 
• Recent maxillofacial surgery
• UncontrollablevomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia
• Patient refusal 

Contraindications for HFNC:

• There are no clear absolute contraindications at this time, as few studies are available.
• Potential contraindications include:
  • Facial anomalies preventing proper fit
  • After upperairwayAirwayABCDE Assessment surgery

Noninvasive Positive Pressure Ventilation

Basic settings controlled by the operator

• PEEPPEEPPressure remaining in the distal airways of the patient at the end of expirationInvasive Mechanical Ventilation or expiratory positiveairwayAirwayABCDE Assessment pressure (EPAP):
  • Pressure remaining in the distal airways at the end ofexpirationExpirationVentilation: Mechanics of Breathing
  • Keeps thealveoliAlveoliSmall polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place.Acute Respiratory Distress Syndrome (ARDS) open to participate in oxygenation
  • Can be ↑ to improve oxygenation (↑ PaO₂)
  • Can be lowered to ↓ oxygenation (↓ PaO₂)
• Inspiratory positiveairwayAirwayABCDE Assessment pressure (IPAP; for BiPAP):
  • The amount of positive pressure delivered with eachinspirationInspirationVentilation: Mechanics of Breathing 
  • ↑ IPAP → ↑tidal volumeTidal volumeThe volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are tv or V with subscript t.Ventilation: Mechanics of Breathing → ↑ventilationVentilationThe total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Ventilation: Mechanics of Breathing → ↓ PaCO₂
  • ↓ IPAP → ↓tidal volumeTidal volumeThe volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are tv or V with subscript t.Ventilation: Mechanics of Breathing → ↓ventilationVentilationThe total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Ventilation: Mechanics of Breathing → ↑ PaCO₂  
  • Note: Changes inventilationVentilationThe total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Ventilation: Mechanics of Breathing can occur only if EPAP is not changed in the same proportion.
• Fraction of inspired oxygen (FiO₂):
  • Percentage of oxygen delivered directly to the individual 
  • ↑ FiO₂ → ↑ oxygenation 
  • ↓ FiO₂ → ↓ oxygenation
• Note:
  • In CPAP: a constantPEEPPEEPPressure remaining in the distal airways of the patient at the end of expirationInvasive Mechanical Ventilation is used → provides continuous positive pressure throughout the breathing cycle
  • In BiPAP: IPAP and EPAP are used → provides different pressures for inhalation and exhalation

Background physiology

• Constant positiveairwayAirwayABCDE Assessment pressure → improves alveolarrecruitmentRecruitmentSkeletal Muscle Contraction → improveshypoxemiaHypoxemiaNeonatal Respiratory Distress Syndrome
• IPAP during inhalation, in addition to the set EPAP/PEEPPEEPPressure remaining in the distal airways of the patient at the end of expirationInvasive Mechanical Ventilation, creates bilevelventilationVentilationThe total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Ventilation: Mechanics of Breathing
  • Thepressure gradientPressure gradientVascular Resistance, Flow, and Mean Arterial Pressure between the IPAP and the EPAP correlates with thetidal volumeTidal volumeThe volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are tv or V with subscript t.Ventilation: Mechanics of Breathing delivered.
  • This relationship ultimately regulates CO₂ clearance.
• NIV can be used to:
  • Improvealveolar ventilationAlveolar ventilationVentilation: Mechanics of Breathing → improvehypercapniaHypercapniaA clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.Neonatal Respiratory Distress Syndrome andacidosisAcidosisA pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up.Respiratory Acidosis
  • RecruitalveoliAlveoliSmall polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place.Acute Respiratory Distress Syndrome (ARDS) and deliver ↑ FiO₂ → help reversehypoxiaHypoxiaSub-optimal oxygen levels in the ambient air of living organisms.Ischemic Cell Damage
    • Maintains openairwayAirwayABCDE Assessment and prevents dynamichyperinflationHyperinflationImaging of the Lungs and Pleura ofalveoliAlveoliSmall polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place.Acute Respiratory Distress Syndrome (ARDS)
    • ImprovesventilationVentilationThe total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Ventilation: Mechanics of Breathing/perfusion (V/Q) mismatch
  • Ameliorate respiratory distress/work of breathingWork of breathingRespiratory muscle contraction during inhalation. The work is accomplished in three phases: lung compliance work, that required to expand the lungs against its elastic forces; tissue resistance work, that required to overcome the viscosity of the lung and chest wall structures; and airway resistance work, that required to overcome airway resistance during the movement of air into the lungs. Work of breathing does not refer to expiration, which is entirely a passive process caused by elastic recoil of the lung and chest cage.Pulmonary Examination
  • Reduce left ventricularpreloadPreloadCardiac Mechanics andafterloadAfterloadAfterload is the resistance in the aorta that prevents blood from leaving the heart. Afterload represents the pressure the LV needs to overcome to eject blood into the aorta.Cardiac Mechanics:
    • Consequently, increasing right ventricular (RV)afterloadAfterloadAfterload is the resistance in the aorta that prevents blood from leaving the heart. Afterload represents the pressure the LV needs to overcome to eject blood into the aorta.Cardiac Mechanics and reducing RVpreloadPreloadCardiac Mechanics
    • Can be beneficial in left-sidedheart failureHeart FailureA heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction.Total Anomalous Pulmonary Venous Return (TAPVR), but should be used with caution inright-sided heart failureRight-Sided Heart FailureEbstein’s Anomaly

High-Flow Nasal Cannula

Basic settings controlled by the operator

There are 2 parameters that affect oxygenation:

• Flow rateFlow ratemaximum flow the ventilator will deliver a set tidal volume in liters per minuteInvasive Mechanical Ventilation (generally optimized first to avoid FiO₂ levels > 60%, when possible)
• FiO₂

Background physiology

• HFNC delivers heated and humidified oxygen for the following physiologic effects:
  • Washes out CO₂ from the anatomicaldead spaceDead spaceThat part of the respiratory tract or the air within the respiratory tract that does not exchange oxygen and carbon dioxide with pulmonary capillary blood.Ventilation: Mechanics of Breathing
  • Can generate a moderate level ofPEEPPEEPPressure remaining in the distal airways of the patient at the end of expirationInvasive Mechanical Ventilation → ↑recruitmentRecruitmentSkeletal Muscle Contraction of collapsedalveoliAlveoliSmall polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place.Acute Respiratory Distress Syndrome (ARDS) 
  • Improved comfort (improvescomplianceComplianceDistensibility measure of a chamber such as the lungs (lung compliance) or bladder. Compliance is expressed as a change in volume per unit change in pressure.Veins: Histology) through:
    • Humidification and warming of oxygen 
    • No mask
  • May have fewer hemodynamic effects than NIPPV
  • Can ↓work of breathingWork of breathingRespiratory muscle contraction during inhalation. The work is accomplished in three phases: lung compliance work, that required to expand the lungs against its elastic forces; tissue resistance work, that required to overcome the viscosity of the lung and chest wall structures; and airway resistance work, that required to overcome airway resistance during the movement of air into the lungs. Work of breathing does not refer to expiration, which is entirely a passive process caused by elastic recoil of the lung and chest cage.Pulmonary Examination
• Best used in acute hypoxicrespiratory failureRespiratory failureRespiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two.Respiratory Failure:
  • May have a role in mild or moderatehypercapnic respiratory failureHypercapnic Respiratory FailureRespiratory Failure
  • May be able to preventintubationIntubationPeritonsillar Abscess in select individuals
  • Can be combined easily with inhaledvasodilatorsVasodilatorsDrugs used to cause dilation of the blood vessels.Thromboangiitis Obliterans (Buerger Disease) 
  • Sometimes use preintubation for oxygen delivery

Complications

The most feared complication for NIV is delaying a potentially lifesaving intervention because of poor patientselectionSelectionLymphocyte activation by a specific antigen thus triggering clonal expansion of lymphocytes already capable of mounting an immune response to the antigen.B cells: Types and Functions. 

• IntubationIntubationPeritonsillar Abscess is not without risk, but it is often necessary in the critical care setting. 
• DelayingintubationIntubationPeritonsillar Abscess in a rapidly deteriorating individual may result in increasedmortalityMortalityAll deaths reported in a given population.Measures of Health Status.

Major complications for noninvasivepositive pressure ventilationPositive pressure ventilationApplication of positive pressure to the inspiratory phase when the patient has an artificial airway in place and is connected to a ventilator.Flail Chest

• BarotraumaBarotraumaInjury following pressure changes; includes injury to the eustachian tube, ear drum, lung and stomach.Invasive Mechanical Ventilation (rare)
• Pressure ulcers/necrosisNecrosisThe death of cells in an organ or tissue due to disease, injury or failure of the blood supply.Ischemic Cell Damage of the nasal bridge (from the mask)
• ClaustrophobiaClaustrophobiaMagnetic Resonance Imaging (MRI) oranxietyAnxietyFeelings or emotions of dread, apprehension, and impending disaster but not disabling as with anxiety disorders.Generalized Anxiety Disorder
• Aspiration fromvomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia
• HypotensionHypotensionHypotension is defined as low blood pressure, specifically< 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause.Hypotension in rightheart failureHeart FailureA heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction.Total Anomalous Pulmonary Venous Return (TAPVR) orhypovolemiaHypovolemiaSepsis in Children 
• ReducedcommunicationCommunicationThe exchange or transmission of ideas, attitudes, or beliefs between individuals or groups.Decision-making Capacity and Legal Competence

Major complication for high-flownasal cannulaNasal CannulaRespiratory Failure

• EpistaxisEpistaxisBleeding from the nose.Granulomatosis with Polyangiitis
• Abdominal distentionAbdominal distentionMegacolon 
• Aspiration
• BarotraumaBarotraumaInjury following pressure changes; includes injury to the eustachian tube, ear drum, lung and stomach.Invasive Mechanical Ventilation (rare, and lower risk than NIPPV and mechanicalventilationVentilationThe total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Ventilation: Mechanics of Breathing)

References

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2. Nickson, C. (2019, September 14). Non-invasive ventilation (NIV). Life in the Fast Lane.https://litfl.com/non-invasive-ventilation-niv/
3. Nishimura, M. (2015). High-flow nasal cannula oxygen therapy in adults. J Intens Care 3(1):15.https://doi.org/10.1186/s40560-015-0084-5
4. Hackett, A.J. (2018). Non-Invasive ventilation in Critical CARE: Positive pressure ventilation AND High-flow oxygen therapy. PulmCCM. Retrieved December 12, 2021, fromhttps://pulmccm.org/critical-care-review/non-invasive-ventilation-in-critical-care-positive-pressure-ventilation-and-high-flow-oxygen-therapy/
5. Soo Hoo, G.W. (2020). Noninvasive ventilation. Medscape. Retrieved December 12, 2021, fromhttps://emedicine.medscape.com/article/304235-overview#a1
6. Hyzy, R.C. (2021). Heated and humidified high-flow nasal oxygen in adults: practical considerations and potential applications. UpToDate. Retrieved December 12, 2021, fromhttps://www.uptodate.com/contents/heated-and-humidified-high-flow-nasal-oxygen-in-adults-practical-considerations-and-potential-applications#H1033389248
7. Hyzy, R.C., McSparron, J.I. (2021). Noninvasive ventilation in adults with acute respiratory failure: benefits and contraindications. UpToDate. Retrieved December 12, 2021, fromhttps://www.uptodate.com/contents/noninvasive-ventilation-in-adults-with-acute-respiratory-failure-benefits-and-contraindications
8. Pinto, V.L., Sharma, S. (2021). Continuous positive airway pressure. StatPearls. Retrieved December 12, 2021, fromhttps://www.ncbi.nlm.nih.gov/books/NBK482178/