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 noninvasive 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) 1
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.) 2
Critical Functions of Resp. System Breathing Gas Exchange Ventilation Oxygenation v The respiratory system performs critical functions. v Transfers O 2 from atmosphere to blood v Removes CO 2 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 CO 2 homeostasis Clinically defined as PaO 2 < 60mmHg or a PaCO 2 > 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 3
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 PaCO 2 above 50 mm Hg. PH depends on the HCO 3 level HCO 3 is influenced by hypercapnia duration. Any disease that affects alveolar ventilation can result in type 2 RF Classification of Respiratory Failure TYPE III RESPIRATORY FAILURE Caused by lung atelectasis. Seen following general anesthesia and surgery Characterized by reduction in functional residual capacity Collapse of dependent lung units TYPE IV RESPIRATORY FAILURE Seen in shock due to hypo-perfusion of respiratory muscles. May be seen in pulmonary edema and cardiogenic shock Basic Process of Gas Exchange (FOURNIER, 2014) Gases (O 2 & CO 2 ) move through the alveoli and cells by simple diffusion Hgb transports O 2 from the lungs to the tissues. Diffusion rate is inversely proportional to the thickness of the respiratory membrane. 4
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 PaO 2 or PaCO 2 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 O 2 need) q Most common cause of exacerbation is infection 5
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 O 2 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 é BP/ Weight Gain Behavioral Problems/Poor Grades 6
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 7
Obesity Hypoventilation Syndrome (OHS) Body mass index > 30 kg/m 2 Awake daytime hypoventilation - Pa CO2 > 45 mmhg - Pao 2 < 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 5 th, 6 th, or 7 th 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 8
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 9
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 10
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. 11
Non-Invasive Ventilation Mode chosen (C-PAP or BiPAP) optimizes lung function Should be adequate to maintain patients comfort & ensure optimum vent/o 2 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 12
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 13
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 14
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 15