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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
