Acute Respiratory Failure PDF

Acute Respiratory Failure Intended Learning Outcomes of the Course (ILOs) Define acute respiratory failure. List causes of acute respiratory failure. Differentiate between the clinical manifestations of type I & type II respiratory failure. Monitor critically...

Acute Respiratory Failure Intended Learning Outcomes of the Course (ILOs) Define acute respiratory failure. List causes of acute respiratory failure. Differentiate between the clinical manifestations of type I & type II respiratory failure. Monitor critically ill patients for signs of hypoxemia. Manage critically ill patients who have hypoxemia. Monitor critically ill patients for signs of hypercapnia. Communicate effectively with critically ill patient who has acute respiratory failure patient. Apply infection control principles when dealing with acute respiratory failure patient. Document assessment cues in patient ICU record Acute respiratory failure is a sudden and life-threatening deterioration in pulmonary gas exchange, resulting in carbon dioxide retention and inadequate oxygenation. It is a major cause of morbidity and mortality in the intensive care units. Definition: Acute respiratory failure (ARF) is defined as a fall in arterial oxygen tension (PaO2) to less than 50 mm Hg (hypoxemia) and a rise in arterial carbon dioxide tension (PaCO2) to greater than 50 mm Hg (hypercapnia), with an arterial pH of less than 7.35. In ARF, the ventilation or perfusion mechanisms in the lung are impaired Classification 1. Acute hypoxemic respiratory failure (type I) 2. Acute hypercapnic respiratory failure (type II), 3. Combined hypoxemic and hypercapnia respiratory failure (type I and type II). Type I failure is a direct defect in oxygenation. Type II failure is a direct defect in ventilation. However, in many instances, the distinction is not clear; many patients exhibit signs and symptoms of a combined type I and type II respiratory failure. A) Acute Hypoxemic Respiratory Failure (Type I): Type I acute respiratory failure is the result of abnormal oxygen transport secondary to pulmonary parenchymal disease, with increased alveolar ventilation resulting in a low PaCO2.The 74 Critical Care Nursing I principal problem in type I acute respiratory failure is the inability to achieve adequate oxygenation, as evidenced by a PaO2 of 50 mm Hg or less and a PaCO2 of 40 mm Hg or less. B) Acute Hypercapnic Respiratory Failure (Type II) Type II acute respiratory failure or ventilatory failure, is the result of inadequate alveolar ventilation and is characterized by marked elevation of carbon dioxide with relative preservation of oxygenation. Hypoxemia results from reduced alveolar pressure of oxygen (PaO2) and is proportionate to hypercapnia. C) Combined Hypoxemic and Hypercapnic Respiratory Failure (Type I and Type II) The combined type of acute respiratory failure develops because of combined inadequate alveolar ventilation and abnormal gas transport. This condition is commonly seen in asthmatic exacerbations, emphysema complicated by a lower respiratory tract infection, severe pneumonia, pulmonary edema, and pulmonary embolism. Pathophysiology Hypoxemia is the result of impaired gas exchange and is the hallmark of acute respiratory failure. Hypercapnia may be present, depending on the underlying cause of the problem. The main causes of hypoxemia are: 1- Alveolar hypoventilation 2- Ventilation/perfusion (V/Q) mismatching, 3- Intrapulmonary shunting. 4- Diffusion impairment Whereas type II respiratory failure usually results from alveolar hypoventilation, which may or may not be accompanied by V/Q mismatching and intrapulmonary shunting. Alveolar Hypoventilation Alveolar hypoventilation occurs when the amount of oxygen being brought into the alveoli is insufficient to meet the metabolic needs of the body. This can be the result of increasing metabolic oxygen needs or decreasing ventilation. Hypoxemia caused by alveolar hypoventilation is associated with hypercapnia and commonly results from extrapulmonary disorders. 75 Critical Care Nursing I Ventilation/Perfusion (V/Q) Mismatching V/Q mismatching occurs when ventilation and blood flow are mismatched in various regions of the lung in excess of what is normal. Blood passes through alveoli that are under ventilated for the given amount of perfusion, leaving these areas with a lower-than-normal amount of oxygen. V/Q mismatching is the most common cause of hypoxemia and is usually the result of alveoli that are partially collapsed or partially filled with fluid. Intrapulmonary Shunting The extreme form of V/Q mismatching, intrapulmonary shunting occurs when blood reaches the arterial system without participating in gas exchange. The mixing of deoxygenated (shunted) blood and oxygenated blood lowers the average level of oxygen present in the blood. Intrapulmonary shunting occurs when blood passes through a portion of a lung that is not ventilated. This may be the result of (1) alveolar collapse secondary to atelectasis or (2) alveolar flooding with pus, blood, or fluid. Hypercapnia generally does not develop unless the shunt is excessive (> 60%). When compared with V/Q mismatch, hypoxemia produced by shunt is difficult to correct by oxygen administration. The distinction between V/Q mismatch and shunt can be made by assessing the response to oxygen supplementation or calculating the shunt fraction following inhalation of 100% oxygen. In most patients with hypoxemic respiratory failure, these 2 mechanisms coexist. Diffusion impairment Another rare but potential cause of impaired oxygenation in the critically ill patient is diffusion defect. Gas exchange between the alveoli and the pulmonary capillaries occurs across the alveolar capillary membrane, which is normally a thin structure, freely permeable to carbon dioxide and oxygen. Gas exchange is compromised by a process that thickens or destroys the membrane e.g. pulmonary fibrosis, ARDS. * A classic sign of diffusion limitation is hypoxemia during exercise but not at rest 76 Critical Care Nursing I Causes of Acute Respiratory Failure: Intrinsic Lung/Airway Diseases  Large Airway Obstruction: (Foreign bodies, Obstructive sleep apnea).  Bronchial Diseases: (Chronic bronchitis, acute bronchiolitis, Asthma).  Parenchymal Diseases: (Pulmonary emphysema, severe pneumonia,  Acute lung injury from various causes (acute respiratory distress syndrome)  Cardiovascular Disease: Cardiac pulmonary edema. Extra pulmonary Disorders  Diseases of the Pleura and the Chest Wall: Pneumothorax, Pleural effusion, Obesity, Traumatic injury to the chest wall, flail chest.  Disorders of the Respiratory Muscles and the Neuromuscular Junction: muscular dystrophies, Botulism, Muscle-paralyzing drugs.  Disorders of the Peripheral Nerves and Spinal Cord: Poliomyelitis, Guillain-Barré syndrome, Spinal cord trauma  Disorders of the Central Nervous System: Sedative and narcotic drug overdose, Head trauma, cerebral hypoxia, Cerebrovascular accident, Sleep apnea syndrome. 77 Critical Care Nursing I Assessment 1- History A complete medical and social history should be obtained from the patient or a family member to determine the patient’s baseline respiratory status on admission. History and Symptoms Profile Pulmonary Symptoms Extrapulmonary Symptoms Dyspnea / Cough Night sweats Hemoptysis / Wheeze Headaches on awakening Chest pain (e.g., pleuritic) Weight changes Orthopnea, paroxysmal nocturnal apnea Fluid retention Snoring, sleep disturbances, daytime drowsiness Nasal stuffiness, discharge Sinus problems Fatigue  Pulmonary Risk Factors  Smoking history: type (cigarettes, cigar, pipe); amount per day; duration (years)  Childhood respiratory diseases/symptoms  Family history of respiratory disease  Environmental exposures: location (e.g., home, work, region); type (e.g., asbestos, silica, gases, aerosols); duration Obesity or nutritional depletion.  Previous History Pulmonary problems Immunizations Number of hospitalizations Treatments Medical diagnosis(es) 2-Physical Findings: Hypoxemia: The classic symptoms are (dyspnea, cyanosis, restlessness, confusion, anxiety, delirium, tachypnea, tachycardia, hypertension, cardiac dysrhythmia and tremor. peripheral cyanosis of the skin, lips, or nail beds suggests the presence of profound arterial hypoxemia, usually with a PaO 2 less than 50 mm Hg. 78 Critical Care Nursing I Hypercapnia: The cardinal symptoms of hypercapnia are dyspnea and headache. Other clinical manifestations include peripheral and conjunctival hyperemia, hypertension, tachycardia, tachypnea, impaired consciousness, papilledema, and asterixis. Uncorrected carbon dioxide narcosis leads to diminished alertness, disorientation, increased intracranial pressure, and ultimately unconsciousness. Other physical findings on examination may include use of accessory muscles of respiration, intercostal or supraclavicular retraction, and paradoxical abdominal movement if diaphragmatic weakness or fatigue is present. 3- Diagnostic studies: Because the signs and symptoms of acute respiratory failure are nonspecific and insensitive, the physician must request an ABG analysis to determine the exact level of PaO2, PaCO2, and blood pH in cases of suspected (ARF). Only determination of the blood gases and pH can confirm the diagnosis. Other diagnostic tests necessary to determine the etiology of acute hypoxemic respiratory failure include:  Serum electrolytes  ECG  Sputum examination  Urine analysis  CT  Pulmonary function test  Bronchogram  CBC  Echocardiography  Bronchoscopy  Chest radiography  Pulmonary angiography Management of Acute Respiratory Failure Treatment of acute respiratory failure warrants immediate intervention to correct or compensate for the gas exchange abnormality and identify the cause. ► Therapy is directed toward correcting the cause and alleviating the hypoxia and hypercapnia. Although the recommended therapeutic intervention may vary according to the specific disease’s pathological process, general management principles are applicable to every patient with acute respiratory failure. ► If alveolar ventilation is inadequate to maintain PaO2 or PaCO2 levels related to respiratory or neurological failure, endotracheal intubation and mechanical ventilation may be lifesaving. ► The initial assessment and the decision to initiate mechanical ventilation should be performed rapidly to minimize the life-threatening. Complications associated with extended hypoxemia (e.g., cardiac dysrhythmias, anoxic encephalopathy). 79 Critical Care Nursing I ► Controlled oxygen therapy and mechanical ventilation are used to increase PaO2 by increasing FiO2 and to normalize pH by increasing minute ventilation. ► Patients with acute hypoxemic respiratory failure should receive immediate treatment with rapidly increased FiO2 and continuous pulse oximetry monitoring until a SaO2 of 90% or higher is obtained. ► Correction of hypoxemia in the acute setting takes precedence over possible attenuation of hypoxic respiratory drive. Therefore, once hypoxemia is reversed, oxygen is titrated to the minimum level necessary for correction of hypoxemia and prevention of significant carbon dioxide retention. ► Patients with acute hypercapnic respiratory failure should be immediately assessed for either an impaired central respiratory drive associated with sedative or narcotic therapy or for underlying bronchospasm secondary to an asthma exacerbation or COPD. ► Reversal agents (opiate antagonists, e.g., naloxone) are used in the case of impaired central respiratory drive, and inhaled bronchodilators and systemic corticosteroids are used in the case of underlying bronchospasm. Nursing management plans for care patient with acute respiratory failure 1. Impaired Gas Exchange related to alveolar hypoventilation Defining Characteristics  Abnormal arterial blood gas (ABG) values; decreased arterial Oxygen tension (PaO2), increased arterial carbon dioxide tension (PaCO2). decreased pH, decreased oxygen saturation (SpO2).  Somnolence / Neurobehavioral changes (restlessness, irritability, confusion)  Tachycardia or dysrhythmias / Central cyanosis Nursing Interventions 1. Initiate continuous pulse oximetry or monitor SpO2 every hour. 2. Collaborate with physician regarding administration of O2 to maintain SpO2 < than 90%. o Administer supplemental oxygen via appropriate oxygen delivery device-to increase driving pressure of oxygen in alveoli. o If supplemental oxygen alone is not effective, administer continuous positive airway pressure (CPAP) or mechanical ventilation with positive end-expiratory pressure (PEEP) to open collapsed alveoli and increase surface area for gas exchange. 80 Critical Care Nursing I 3. Prevent hypoventilation. o Position patient in high-Fowler's position or semi-Fowler's position to promote diaphragmatic descent and maximal inhalation. o Assist with deep-breathing exercises and incentive spirometry with sustained maximal inspiration 5 to10 times/hr to help reinflate collapsed portions of lung. o Treat pain, if present, to prevent hypoventilation and atelectasis. Implement plan for Acute Pain Related to Transmission and Perception of Cutaneous, Visceral, Muscular, or Ischemic Impulses. 4. Assist physician with incubation and initiation of mechanical Ventilation as indicated. 2. Impaired Gas Exchange related to ventilation/ perfusion mismatching or Intrapulmonary shunting Defining Characteristics  Abnormal ABG values (decreased Pao2), decreased (Spo2)  Somnolence / Neurobehavioral changes (restlessness, irritability, confusion)  Central cyanosis Nursing Interventions 1. Initiate continuous pulse oximetry or monitor SpO2 every hour. 2. Collaborate with physician regarding administration of O2 to maintain SpO2 < than 90%. o Administer supplemental oxygen via appropriate oxygen delivery device to increase driving pressure of oxygen in alveoli. o If supplemental oxygen alone is not effective, administer CPAP or mechanical ventilation with PEEP to open collapsed alveoli and increase surface area for gas exchange. 3. Position patient to optimize ventilation/perfusion matching. o For patient with unilateral lung disease, position with the good lung down because gravity will improve perfusion to this area, and this will best match ventilation with perfusion. o For patient with bilateral lung disease, position with right lung down because right lung is larger than left lung and affords a greater area for ventilation and perfusion, or o Change position every 2 hours, favoring positions that improve oxygenation. o Avoid any position that seriously compromises oxygenation status. 5. Perform procedures only as needed and provide adequate rest and recovery time in between to prevent desaturation. 81 Critical Care Nursing I  6. Collaborate with physician regarding administration of drugs. o Sedatives, to decrease ventilator asynchrony and facilitate patient's sense of control. o Neuromuscular blocking agents, to prevent ventilator asynchrony and decrease oxygen demand. o Analgesics, to treat pain if present. Implement plan for Acute Pain Related to Transmission and Perception of Cutaneous, Visceral, Muscular, or Ischemic Impulses. 7. If secretions are present, implement plan for Ineffective Airway Clearance Related to Excessive Secretions or Abnormal Viscosity of Mucus. 3. Ineffective airway clearance related to excessive secretion or abnormal viscosity of mucus Defining Characteristics  Abnormal breath sounds (displaced normal sounds, adventitious sounds, diminished or absent sounds)  Ineffective cough with or without sputum / Tachypnea, dyspnea Nursing Interventions 1. Assess sputum for color, consistency, and amount. 2. Asses for clinical manifestations of pneumonia. 3. Provide for maximal thoracic expansion by repositioning, deep breathing, splinting, and pain management to avoid hypoventilation and atelectasis. 4. Maintain adequate hydration by administering oral and intravenous fluids (as ordered) to thin secretions and facilitate airway clearance. 5. Provide humidification to airways via oxygen-delivery device or artificial airway to thin secretions and facilitate airway clearance. 6. Administer inhalation therapy every 4 hours to facilitate expectoration of sputum. 7. Collaborate with physician regarding administration of drugs. o Bronchodilators, to treat or prevent bronchospasm and facilitate expectoration of mucus. o Mucolytics and expectorants, to enhance mobilization and removal of secretions. o Antibiotics, to treat infection. 8. Assist with directed coughing exercises to facilitate expectoration of secretions. 9. Suction as necessary to assist with secretion removal. 10. Reposition patient at least every 2 hours or use continuous lateral rotation therapy to mobilize and prevent stasis of secretions. 82 Critical Care Nursing I 11. Consider chest physiotherapy (postural drainage and chest percussion) 3 to 4 times per day in a patient with large amounts of sputum to assist with expulsion of retained secretions. 12. Allow rest periods between coughing sessions, chest physiotherapy, suctioning, or any other demanding activities to promote energy conservation. 4. Ineffective Breathing Pattern related to musculoskeletal fatigue or neuromuscular Impairment Defining Characteristics  Unequal chest movement  Abnormal ABG: increased PaCO2, decreased pH  Shortness of breath, dyspnea  Nasal flaring  Use of accessory muscles  Assumption of 3-point position  Tachypnea  Thoracoabdominal asynchrony Nursing Interventions and Rationale 1. Prevent unnecessary exertion to limit drain on patient's ventilatory reserve. 2. Assist with pursed-lip and diaphragmatic breathing techniques to facilitate diaphragmatic descent and improved ventilation. Diaphragmatic breathing a. Sit in upright position. b. Place One hand on abdomen just above waist and other hand on upper chest. c. Breathe in through nose and feel lower hand push out; upper hand should not move. d. Breathe nut through pursed lips, and feel lower hand move in. 3. Position patient in high-Fowler's or semi-Fowler's position to promote maximal inhalation. 4. Assist physician with intubation and initiation of mechanical ventilation as indicated. 5. Impaired Spontaneous Ventilation related to respiratory muscle fatigue or metabolic Factors Defining Characteristics  Dyspnea and apprehension  Decreased tidal volume  Increased metabolic rate  Increased heat rate  Increased restlessness 83 Critical Care Nursing I   Abnormal arterial blood gas (ABG) values: decreased arterial oxygen tension (PaO2), increase arterial carbon dioxide tension (PaCO2), decreased pH, decreased arterial oxygen saturation (SpO2) Nursing Interventions 1. Collaborate with physician regarding application of pressure support to ventilator to assist patient in overcoming the work of breathing imposed by the ventilator and endotracheal tube. 2. Carefully snip excess length from proximal end of endotracheal tube to decrease dead space and thereby decrease the work of breathing. 3. Collaborate with physician and dietitian to ensure that at least 50% of diet's non-protein caloric source is in form of fat versus carbohydrates to prevent excess carbon dioxide production. 4. Collaborate with physician and respiratory therapist regarding best method of weaning for individual patients because each situation is different, and a variety of weaning options are available. 5. Collaborate with physician & physical therapist regarding progressive ambulation plan to promote overall muscle conditioning & respiratory muscle functioning. 6. Treat pain if present, to prevent hypoventilation. 7. Ensure that patient: receives at least 2- to 4-hr intervals of uninterrupted sleep in a quiet, dark room 8. Place patient in semi-Fowler's position or in a chair at bedside for best use of ventilatory muscles and to facilitate diaphragmatic descent. 9. Explain weaning procedure to patient before the trial so that patient will understand what to expect and how to participate. 10. Monitor patient during the weaning trial for evidence of respiratory muscle fatigue to avoid overtiring patient. 6. Imbalanced Nutrition: Less than Body Requirements related to lack of exogenous Nutrients or increased metabolic demand Nursing Interventions 1. Inquire if patient has any food allergies and food preferences to ensure the food provided to patient is not contraindicated. 84 Critical Care Nursing I 2. Monitor patient's caloric intake and weight daily to ensure adequacy of nutritional interventions. 3. Collaborate with dietitian regarding patient's nutritional anti caloric needs to determine the appropriateness of patient's diet to meet those needs. 4. Monitor patient for signs of nutritional deficiencies to facilitate evaluation of extent of nutritional deficit. 5. Provide patient with oral care before eating to ensure optimal consumption of diet. 6. Assist patient to eat as appropriate to ensure optimal consumption of diet. 7. Collaborate with physician regarding the administration of parenteral and enteral nutrition as needed. 7. Impaired Verbal Communication 1. Assess patient ability to comprehend, speak, read, and write. 2. Ask simple, short questions. Use gestures, pantomime, and facial expressions to give patient additional clues. 3. Stand in patient's line of vision, giving a good view of your face and hands. 4. Have patient try to write with a pad and pencil. Offer pictures and alphabet letters for reference. 5. Make flash cards with pictures or words depicting frequently used phrases (e.g., glass of water, bedpan). 6. Maintain an uncluttered environment and decrease external distractions that could hinder communication. 7. Maintain a relaxed and calm manner, and explain all diagnostic, therapeutic, and comfort measures before initiating them. 8. Do not shout or speak in a loud voice. Hearing loss is not a factor in aphasia, and shouting will not help. 9. Have only one person talk at a time. It is more difficult for a patient to follow a multisided conversation. 10. Use direct eye contact, and speak directly to patient in unhurried, short phrases. 11. Give one-step commands and directions and provide cues through pictures and gestures. 12. Try to ask questions that can-he answered with a "yes" or a "no," and avoid topics that are controversial, emotional, abstract, or lengthy. 85 Critical Care Nursing I 13. Listen to patient in unhurried manner and wait for patient's attempt to communicate. o Expect a time lag from when you ask patient something until patient responds. o Accept patient's statement of essential words without expecting complete sentences. o Avoid finishing sentences for patient, if possible. o Wait approximately 30 seconds before providing the word that patient may be attempting to find (except when patient is very frustrated and needs something quickly, such as a bedpan). o Rephrase patient's message aloud to validate it. o Do not pretend to understand patient's message if you do not. 14. Encourage patient to speak slowly in short phrases and to say each word clearly. 15. Ask patient to write the message, if able, or draw pictures if only verbal communication is affected. 16. Observe patient's nonverbal clues for validation (e.g., answers "yes" but shakes head "no"). 17. When handing an object to patient, state what it is because hearing language spoken is necessary to stimulate language development. 18. Talk to patient as an adult. Be respectful and avoid "talking down" to patient. 19. Do not discuss patient's condition or hold conversations in patient's presence without including patient in the discussion. This may be the reason some aphasic patients develop paranoid thoughts. 20. Delay conversation if patient is tired. Symptoms of aphasia worsen if patient is fatigued, anxious, or upset. 8. High risk for Aspiration Nursing Interventions 1. Assess GI function to rule out hypoactive peristalsis and abdominal distention. 2. Position patient with head of bed elevated 30 degrees to prevent gastric reflux through gravity. 3. Maintain patency and functioning of nasogastric suction apparatus to prevent accumulation of gastric contents. 4. Provide frequent mouth care to prevent colonization of oropharynx with bacteria and inoculation of lower airways. 5. Ensure that endotracheal /tracheostomy cuff is properly inflated to limit aspiration of oropharyngeal secretions. 86 Critical Care Nursing I  6. Treat nausea promptly; collaborate with physician on an order for antiemetic to prevent vomiting and resultant aspiration. 9. High risk for Infection Nursing Interventions 1. Wash hands before and after patient care to reduce the transmission of microorganisms. 2. Use aseptic technique for insertion and manipulation of invasive monitoring devices, intravenous (IV) lines, and urinary drainage catheters to maintain sterility of environment. 3. Stabilize all invasive lines and catheters to avoid unintentional manipulation and contamination. 4. Use aseptic technique for dressing changes to prevent contamination of wounds or insertion sites. 5. Change any line placed under emergent conditions within 24 hours because aseptic technique is usually breached during an emergency. 6. Collaborate with physician to change any dressing that is saturated with blood or drainage because these are media for microorganism growth. 7. Minimize use of stopcocks and maintain caps on all stopcock ports to reduce the ports of entry for microorganisms. 8. Avoid the use of nasogastric tubes, nasoendotracheal tubes, and nasopharyngeal suctioning in patient with suspected cerebrospinal fluid leak to decrease the incidence of central nervous system infection. 9. Change ventilator circuits with humidifiers no more often than every 48 hours to avoid introducing microorganisms into the system. 10. Maintain a closed urinary drainage system to decrease incidence of urinary infections. 11. Keep urinary drainage tubing and bag below level of patient bladder to prevent backflow of urine. 12. Assess urinary drainage tubing for kinks to prevent stasis of urine. Extra Sources  https://youtu.be/UmKx7I0Broo  https://youtu.be/4Q23598FsuQ  https://www.registerednursern.com/lung-anatomy-and-physiology-quiz/ 87 Critical Care Nursing I  Mechanical ventilation Intended Learning Outcomes of the Course (ILOs)  Identify the purposes of mechanical ventilation.  List the indications for mechanical ventilation.  Enumerate the criteria for institution of ventilatory support.  Explain classifications of mechanical ventilation.  Differentiate between the different modes of mechanical ventilation.  Discuss common ventilator setting  Recognize the different ventilator alarms with its causes and management.  List the criteria for weaning from ventilatory support.  Explain the different methods for weaning from mechanical ventilation.  Provide comprehensive nursing care for mechanically ventilated patients according to priorities.  Discuss the role of nurse regarding weaning from mechanical ventilation. Mechanical Ventilation is ventilation of the lungs by artificial means usually by a ventilator. Endotracheal intubation and mechanical ventilation are instituted when a patient’s PaO 2 cannot be maintained by the basic methods of oxygen delivery systems, such as masks, cannula. A ventilator delivers gas to the lungs with either negative or positive pressure. Purposes: It aims to  Enhance ventilation, i.e. for adequate tissue oxygenation.  Reduce the work of breathing and improve patient’s comfort.  Improve lung volume Indications: Extra-pulmonary disorders: Neuromuscular diseases as there is a failure of the normal respiratory neuromuscular system such as Myasthenia Gravis, Guillain-Barré Syndrome, and Poliomyelitis. 94 Critical Care Nursing I  Drug overdose Trauma, tumor, infarction Brain edema Chest wall trauma Obesity Circulatory failure as in case of Cardiac arrest, sever shock, left ventricular failure, after cardiac surgery Intra-pulmonary disorders Chronic Obstructive lung Disease in the form of asthma, chronic bronchitis, or emphysema. Conditions such as pulmonary edema, pulmonary embolism atelectasis, pulmonary fibrosis. Infectious diseases of the lung such as pneumonia, tuberculosis. Cystic fibrosis. Acute respiratory distress syndrome Criteria for ventilatory support institution Parameters Ventilation indicated Normal Pulmonary function Respiratory rate > 35 10-20 Tidal volume