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TREATMENT OF ACUTE RESPIRATORY FAILURE OF VARIABLE CAUSES: INVASIVE VS. NON-INVASIVE VENTILATION

Louisa Chika Ikpeama, DNP, CCRN, ACNP-BC

Objectives

¨  Identify health care significance of acute respiratory failure (ARF)

¨  List potential causes of acute respiratory failure ¨  Discuss the four different types of ARF ¨  Identify standard conservative medical treatment for

ARF ¨  Discuss appropriateness of invasive versus non-

invasive mechanical ventilation

Health care significance of ARF

¨  The most common reasons for admission to the intensive care unit (ICU)

¨  Common diagnosis in patients admitted for acute care.

¨  The leading cause of death from pneumonia and chronic obstructive pulmonary disease (COPD) in the United States.

¨  Expensive health care resource utilization (Fournier, 2014)

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Respiratory System

¨  Central (Medulla) & Peripheral (Phrenic) NS ¨  Respiratory Muscles ¨  Chest Wall ¨  Lung ¨  Upper Airway ¨  Bronchial Tree ¨  Alveoli ¨  Pulmonary Vasculature

The Respiratory System and Critical Functions http://classes.midlandstech.com/carterp/Courses/bio211/chap22/chap22.htm

Ventilator Control (Carvalho, P.)

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Critical Functions of Resp. System

¨  Breathing ¨  Gas Exchange ¨  Ventilation ¨  Oxygenation v  The respiratory system performs critical functions. v  Transfers O2 from atmosphere to blood

v  Removes CO2 from blood

Acute Respiratory Failure (ARF)

¨  Inability of the respiratory system to do its job: - Meet metabolic demands of the body - Fail to oxygenate the body - Fail to meet CO2 homeostasis

¨  Clinically defined as PaO2 < 60mmHg or a PaCO2 > 45mmHg while breathing

¨  Respiratory failure (RF) is classified into four types (I, II, III, & IV)

Common Respiratory Disorders

q  Chronic obstructive pulmonary disease (COPD) q  Obstructive Sleep Apnea (OSA) q  Obesity Hypoventilation Syndrome (OHS) q  Volume Overload/Flash Pulmonary Edema/CHF q  Pneumonia q  Acute Respiratory Distress Syndrome (ARDS) q  Etc

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Classification of Respiratory Failure (RF)

¨  Type I or hypoxemic RF is failure to exchange oxygen

¨  Indicated by a PaO2 value < 60 with a normal or low PaCO2 value.

¨  The most common causes of type 1 RF are V/Q mismatch & shunts.

¨  Type 2 or hypercapnic RF is failure to exchange or remove CO2

¨  Indicated by PaCO2 above 50 mm Hg.

¨  PH depends on the HCO3 level

¨  HCO3 is influenced by hypercapnia duration.

¨  Any disease that affects alveolar ventilation can result in type 2 RF

Classification of Respiratory Failure

¨  Caused by lung atelectasis.

¨  Seen following general anesthesia and surgery

¨  Characterized by reduction in functional residual capacity

¨  Collapse of dependent lung units

¨  Seen in shock due to hypo-perfusion of respiratory muscles.

¨  May be seen in pulmonary edema and cardiogenic shock

TYPE III RESPIRATORY FAILURE

TYPE IV RESPIRATORY FAILURE

Basic Process of Gas Exchange (FOURNIER, 2014)

¨  Gases (O2 & CO2) move through the alveoli and cells by simple diffusion

¨  Hgb transports O2 from the lungs to the tissues.

¨  Diffusion rate is inversely proportional to the thickness of the respiratory membrane.

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Basic Process of Gas Exchange

¨  Lung’s large surface area is influenced by alveolar size and inflation.

¨  Surface area is directly proportional to diffusion; a large surface area favors diffusion

¨  gas has an inherent ¨  Gas has inherent solubility and molecular weight. ¨  Driving pressure is the gradient between PaO2 or

PaCO2 in the alveoli and the pressure ¨  of these gases in the blood.

Ventilation and Perfusion (V/Q) (FOURNIER, 2014)

Chronic Obstructive Pulmonary Disease (COPD)

¨  COPD is a partially reversible progressive disease characterized by airway obstruction & abnormal inflammatory changes within the lung parenchyma

¨  Sometimes called emphysema ¨  COPD exacerbation is an acute change in patient’s baseline symptoms (cough, dyspnea, sputum, and O2 need) q  Most common cause of exacerbation is infection

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COPD Exacerbation

¨  3rd leading cause of death in the United States

¨  12 million diagnosed and additional 12 million undiagnosed

q  1.5 million emergency room visits in 2000 ¨  726,000 hospitalizations in 2000 q  $18 b in direct costs & $14.1 billion in

indirect costs

Obstructive Sleep Apnea (OSA)

¨  Condition of recurrent episodes of breathing pauses due to complete or partial airway collapse resulting in O2 desaturation.

¨  Diagnosis by polysomnography ¨  Presence of at least 5 obstructive respiratory events

(apneas, hypopneas, or respiratory effort related arousals) in 1 hour. HTN/Mortality and Sudden Death

Obstructive Sleep Apnea (OSA)

¨  Snoring/gasping/choking during sleep ¨  Restless Sleep ¨  Fatigue, Irritability ¨  Daytime Sleepiness ¨  Headaches ¨  Depression ¨  Difficulty Concentrating ¨  éBP/ Weight Gain ¨  Behavioral Problems/Poor Grades

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Obstructive Sleep Apnea (OSA)

v  Impact of OSA ¨  Systemic HTN ¨  Atherosclerosis ¨  CHF/Diastolic Dysfunction ¨  Cardiac Arrhythmias ¨  Stroke ¨  Increased Mortality and Sudden Death

Heart Failure

¨  Structural or functional abnormality that impairs the pump mechanism (Systolic or diastolic dysfunction)

¨  Results in excess fluid accumulation & resultant symptoms (SOB, dyspnea, edema, congestion)

¨  Decreases cardiac output (weakness, fatigue) ¨  Various classifications (NY I, II, III, IV; AHA ABCD)

Obesity Hypoventilation Syndrome (OHS)

¨  OHS is a diagnosis of exclusion ¨  Linked with obstructive sleep apnea (OSA) ¨  90% OF OSA patients have simple sleep

disordered breathing (obstructive apnea) ¨  10% have sleep hypoventilation without significant

apneic events ¨  Differentiating both is through polysomnography

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Obesity Hypoventilation Syndrome (OHS)

¨  Body mass index > 30 kg/m2

¨  Awake daytime hypoventilation - PaCO2 > 45 mmHg - Pao2 < 70 mmHg

¨  Non-obstructive sleep hypoventilation ¨  Exclusion of other causes of alveolar

hypoventilation

Obesity Hypoventilation Syndrome (OHS)

¨  Prevalence of OHS among hospitalized patients with BMI > 35 IS 35%

¨  Conflicting prevalence in men versus women ¨  Diagnosis usually made in the 5th, 6th, or 7th decade ¨  Respiratory failure usually prompts work-up for

diagnosis

Signs & Symptoms of ARF

¨  Respiratory System - Dyspnea, Tachypnea, accessory muscles, shallow breathing, poor air entry, stridor etc.

¨  Integumentary System - Pallor, Cyanosis, Diaphoresis

¨  Cardiovascular System - tachycardia, arrhythmias, chest pain, HTN/Hypotension

¨  Neuro/CNS System – lethargy, anxiety, restlessness, confusion, fatigue, agitation, obtundation, Coma

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Principles of RF Management

¨  Reverse and prevent hypoxemia ¨  Secondary goal is control of respiratory acidosis ¨  Support oxygenation and ventilation ¨  Reduce work of breathing ¨  Monitor CNS and CVS closely ¨  Treat underlying causes ¨  Optimize pulmonary function

¨  Pharmacologic Agents §  Bronchodilators (Short- and long-acting) §  Corticosteroids in certain patients §  Antibiotics to treat infection §  Mucolytics as needed §  Oxygen Therapy §  Diuretics

Optimizing Lung Function

¨  Smoking Cessation §  Various formulations and delivery system available ¨  Pulmonary Rehabilitation ¨  Incentive Spirometry ¨  Chest Physiotherapy

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Mechanical Ventilation

Invasive vs Non-Invasive Ventilation

Invasive vs Non-Invasive Ventilation

¨  Severity of distress or illness? ¨  Patent Airway ¨  Appropriate mental status? ¨  Cooperation with treatment plan? ¨  Exclusion of comorbid conditions? ¨  Secretion management? ¨  Hemodynamically stable?

Invasive vs Non-invasive Ventilation

¨  Inability to maintain or protect airway or manage secretions

¨  Facial trauma ¨  Vomiting ¨  Upper airway obstruction ¨  AMS/Confusion/agitation ¨  Bowel obstruction ¨  Untreated Pneumothorax ¨  Hemodynamic instability

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Non-Invasive Ventilation

¨  Established in the 1980s ¨  A valuable tool in the management of acute

respiratory failure (ARF). ¨  Any form of ventilator support applied through a

non-invasive interface ¨  Includes expiratory pressure (CPAP), bi-level with

both inspiratory and expiratory pressure support (BIPAP), Volume and pressure-cycled systems, and Proportional assist ventilation

Non-Invasive Ventilation

¨  NIV modality has been shown to reduce the need for endotracheal (ET) intubation

¨  Decreases adverse effects associated with invasive mechanical ventilation

¨  Decreases time in intensive care ¨  Lowers mortality rate ¨  Reduces overall length of hospital stay. ¨  Should be considered in all acute respiratory failure

despite optimum medical treatment.

Non-Invasive Ventilation

¨  Important treatment strategy when invasive ET intubation is not an option

¨  Few requirements for sedation, central venous catheters, urinary catheters, and other invasive lines compared to ET intubation

¨  Interfaces fit tight on the face or nose and are held in place with straps.

¨  Interfaces include nasal prongs, total face masks, oro-nasal masks, and helmets.

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Non-Invasive Ventilation

¨  Mode chosen (C-PAP or BiPAP) optimizes lung function

¨  Should be adequate to maintain patients comfort & ensure optimum vent/o2

¨  C-PAP is usually adequate in chronic respiratory failure

¨  Bi-PAP mode required in acute on chronic failure not at goal on CPAP

Contraindications to NIV

¨  Facial trauma or recent facial surgery ¨  Intracranial Bleeding ¨  Untreated abdominal distention ¨  Active GI bleeding ¨  Inability to protect airway or clear secretions ¨  Uncooperative or agitated patient ¨  Hemodynamic instability

NIPPV Mask Interfaces

Mask Interfaces

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Mask Interfaces

q  Choice of mask can greatly affect outcome more than the ventilator mode for patients with hypercapnic respiratory failure, irrespective of underlying pathology.

q  Tolerance greatly affected by mask comfort q  Comfort of mask extends time on the ventilator

Non-invasive Ventilation

q  Critical Elements for success continued §  Selection of a comfortable mask, full-face at initiation §  Close clinical monitoring is crucial especially at initial

period §  Ongoing assessment to identify treatment failure §  ABG 1 hour after initiation §  Adequate pressure and oxygen titration based on

ABG §  Wean on individual patient response to treatment

Features of NIV Failure

¨  Worsening mental status ¨  Lack of improvement of ABG values ¨  Persistent hypoxia ¨  Increased use of accessory muscles/Dyspnea ¨  Poor mask interface tolerance ¨  Hypotension and bradycardia

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Non-invasive Ventilation

q  Ethical Considerations §  NIPPV is considered a life support measure §  Ethical implications for pts who opt out of advanced

life support §  Determine and clarify pts understanding of NIPPV §  Update Do Not Resuscitate orders to reflect

preference for NIPPV

Invasive Ventilation

¨  Reserved for life threatening situations ¨  NIV not appropriate ¨  Requires an endotracheal or tracheal tube

interface ¨  Severe hypercapnia and worsening hypoxemia ¨  Goal is to provide respiratory support till reversal

of cause(s) of deterioration

Invasive & Non-invasive Ventilation

Critical Elements for success ¨  Selection of appropriate patients ¨  Selection of appropriate level of care ¨  Trained and experienced personnel ( NP, MD, RT,

RN, PA) ¨  Initiate appropriate ventilation as early as possible ¨  Selection of a comfortable mask ¨  Close clinical monitoring is crucial

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Invasive & Non-invasive Ventilation

Critical Elements for success ¨  Ongoing assessment to identify treatment failure ¨  ABG 1 hour after initiation ¨  Adequate titration based on ABG ¨  Wean on individual patient response to treatment ¨  Prevent complications of immobility ¨  Address nutritional needs

Practice Implications

¨  Practice Implication - Providers should make optimized decision related to invasive and non-invasive ventilation when optimized medical therapy proves inadequate - Maintain effectiveness & efficiency of care - Use evidence-based care approach - Be responsible health care spending

Contact

Louisa Chika Ikpeama, DNP, RN, CCRN,ACNP-BC

Michael E. Debakey VA Medical Center 2002 Holcombe Boulevard

Houston Texas 77030

Louisa.ikpeama@va.gov