ACUTE RESPIRATORY FAILURE Dr. Abdelkarim Al oweidi Al Abbadi Faculty Of Medicine Department Of Anesthesia

ACUTE RESPIRATORY FAILURE Definitions Hypoxemia is reduction in the oxygen content in the arterial blood system. Tissue hypoxia is reduction in the oxygen delivery to the tissues, caused by reduction Of oxygen content and or reduction in cardiac output.

ACUTE RESPIRATORY FAILURE DEFINITION IT IS ASYNDROME OF INADEQUATE GAS EXCHANGE DUE TO DYSFUNCTION OF ONE OR MORE ESSENTIAL COMPONENTS OF RESPIRATORY SYSTEM.

ACUTE RESPIRATORY FAILURE

CHEST WALL (INCLUDING PLEURA AND DIAFRAGM ) AIRWAYS PULMONARY CIRCULATION NERVES CNS OR BRAIN STEM ACUTE RESPIRATORY FAILURE

EPIDEMIOLOGY ICIDENCE : ABOUT /YR IN USA 36 DIE DURING HOSPITALIZATION MORTALITY AND MORBIDITY INCREASE WITH AGE COMORBIDITIES ACUTE RESPIRATORY FAILURE

CLASIFICATION TYPE I OR HYPOXEMIC (PaO2 < 60 at sea level) : FAILURE OF OXYGEN EXCHANGE INCREASED SHUNT FRACTION (QS/QT ) DUE TO ALVEOLAR FLOODING HYPOXEMIA REFRACTORY TO O2 SUPPLEMNT TYPE II OR HYPERCAPNIC PaCO2>50 FAILURE TO REMOVE OR TO EXCHANGE CO2 DECREASE ALVEOLAR MIN. VENTIL.(VA) OFTEN ACCOMPANIED BY HYPOXEMIA THAT CORRECTS WITH SUPPLEMENTAL O2 ACUTE RESPIRATORY FAILURE

TYPE III RESP.FAILURE : PERIOPERATIVE RESP FAILURE INCREASED ATELECTASIS DUE TO LOW (FRC) IN SITTING OR ABNORMAL ABD.MECHANICS RESLUT IN TYPE I OR II RESP FAILURE AMELIORATED BY ANESTHETICS OP TECHNIQUE,POSTURE. INCENTIVE SPIROMETRY. ANALGESIA TYPE IV RESP FAILURE : IN SHOCK PATIENT VENTLATED TO STABILIZE GAS EXCHANGE. TO LOWER RESP MUSCLE O2 CONSUMPTION ACUTE RESPIRATORY FAILURE

CLASSIFICATION ACUTE CHRONIC ACUTE ON CHRONIC Ex. Acute Exacerbation of COPD ACUTE RESPIRATORY FAILURE

Pathophysiology : Mechanisms  Hypoxemic failure  Ventilation/Perfusion (V/Q) mismatch  Shunt  Exacerbated by low mix of venous O2 (SvO2)  Hypercapnic failure  Decreased minute ventilation (MV) relative to demand ACUTE RESPIRATORY FAILURE

. Pathophysiology : Etiologic Categories * Nerve system * Neuromuscular Failure (Type II) transmission failure - Central hypoventilation (Type II) - Neuropathies - Myasthenia gravis *Muscle (pump) * Airway failure Failure (Type II) (Type II) - Muscular dystrophies - Obstruction - Myopathies - Dysfunction

Pathophysiology :Etiologic Categories * Chest wall and pleural *Alveolar unit failure Space failure (Type II) (Type I) - Kyphoscoliosis - Collapse - Morbid obesity - Flooding: edema, blood, - Pneumothorax pus,aspiration - Hydrothorax - Fibrosis - Hemothorax * Pulmonary vasculature failure (Type I) - Pulmonary embolism - Pulmonary hypertension ACUTE RESPIRATORY FAILURE

Causes  Type I respiratory failure  Pneumonia  Cardiogenic Pulmonary Edema  Increase hydrostatic pressure  Non-Cardiogenic pulmonary edema  Increased permeability  Acute Lung Injury (ALI)  Acute respiration distress syndrome (ARDS)  Pulmonary embolism  Atelectasis  Pulmonary fibrosis ACUTE RESPIRATORY FAILURE

Causes  Type II respiratory failure  Central hypoventilation  Asthma  COPD  Neuromuscular and chest wall disorders  Myopathies  Neuropathies  Kyphoscolisis  Myasthenia gravis  Obesity Hypoventilation Syndrome ACUTE RESPIRATORY FAILURE

Causes Type III respiratory failure Inadequate analgesia Obesity, acites Smoking Excessive airway secretion Type IV respiratory failure Cardiogenic shock Septic shock Hypovolemic shock

ACUTE RESPIRATORY FAILURE Diagnosis : History Sepsis suggested by fever, chills Pneumonia -cough, Sputum, chest pain P E – dyspnea, chest pain COPD – Smoking. Cough. Sputum Cardiogenic pulmonary edema- chest pain. PND. Orthopnea

ACUTE RESPIRATORY FAILURE Noncardiogenic Respiratory failure – sepsis,Aspiration. Blood.Transfusion Weakness – suggest Neuromuscular respiratory failure or toxins Exposure History – ASTHMA. Aspiration, Inhalational injury, Interstitial lung disease

ACUTE RESPIRATORY FAILURE DIAGNOSIS- PHYSICAL FINDING Hypotension- poor perfusion –in sepsis, embolus Hypertension –with poor perfusion in Cardiogenic pulmonary edema Wheezing – Suggest A/W obstruction : Bronchospasm upper or lower airway pathology Secretion Pulmonary edema

Stridor suggests upper airway obstruction Elevated jugular venous pressure suggests right ventricular dysfunction due to accompanying pulmonary hypertension Tachycardia and arrhythmias may be the cause of cardiogenic pulmonary edema ACUTE RESPIRATORY FAILURE

Labortary ABG CBC Cardiac serologic markers Troponin, (CK-MB) Microbiology Cultures, Sputum, tracheal aspirate Blood, urine and body fluid ACUTE RESPIRATORY FAILURE

Chest X-ray ECG Echocardiography Pulmonary function tests Bronchoscopy

ACUTE RESPIRATORY FAILURE Management ABC’s Ensure airway is adequate Oxygen therapy and assisted ventilation if needed Support circulation

ACUTE RESPIRATORY FAILURE Treatment of a specific cause when possible Infection Airway obstruction Improve cardiac function Positive airway pressure, diuretics, inotropy

Treatment of Under lying Disease Bronchodilatation Removal of Secreations Antibiotics.

ACUTE RESPIRATORY FAILURE Mechanical ventilation Non-invasive (if patient a/w is protected and hemodynamically stable) Mask CPAP.BIPAP Invasive (Endotracheal tube), AND MECHANICAL VENTILATION.

ACUTE RESPIRATORY FAILURE

Indication for mechanical ventilation Cardiac or respiratory arrest Tachy/bradypnea Respiratory acidosis Refractory hypoxemia Depressed level of consciousness Shock Inability to excrete secretions

ACUTE RESPIRATORY FAILURE Neuromuscular disease with V/C less than ML/kg Increased ICP OTHERS

ACUTE RESPIRATORY FAILURE Invasive vs. Non-Invasive ventilation Non-invasive in : COPD Cardiogenic pulmonary edema Obesity,hypoventilation syndrome, Asthma

ACUTE RESPIRATORY FAILURE Goals of Mechanical Ventilation Improve ventilation by augmenting respiratory rate and tidal volume Assistant for neural or muscle dysfunction Sedated, paralyzed or comatose patient Neuropathy Intra-operative ventilation Correct respiratory acidosis Match respiratory demand Rest respiratory muscles

ACUTE RESPIRATORY FAILURE Correct hypoxemia High FIO2 PEEP Improve cardiac function Decrease preload Decrease afterload Decrease metabolic demand

ACUTE RESPIRATORY FAILURE Permissive Hypercapnia Strategy that allows PaCO2 to rise by accepting lower alveolar minute ventilation to avoid specific risks: Dynamic hyperinflation (Auto-PEEP) and barotrauma in patients with asthma. Ventilator associated with lung injury in ARDS. Contraindicated in ICP,MYOCARDIAL ISCHEMIA, SEVERE RIGHT OR LEFT VENRTICULAR FAILURE, OR SEVERE METABOLIC ACIDOSIS

ACUTE RESPIRATORY FAILURE

Other issues to consider when initiating Mechanical Ventilation Don’t wait respiratory acidosis with evidence of : Inability to protect airway RR > 35 /minute Respiratory muscle fatigue Consider risks and benefits of mechanical vetilation

ACUTE RESPIRATORY FAILURE Other issues in intubated and Ventilated patients Elevate head > 30 degree Ulcer and DVT prophylaxis In patient with ALI use small TV (6 ml/kg and pressure of 30 cmH2O Modify ventilation according to the patient

ACUTE RESPIRATORY FAILURE Monitoring Routine Monitoring ECG Blood Pressure Pulse Oximetry TemperatureCapnography

CARE OF VENTILATED PATIENTS SEDATION ANALGESIA NURSING CARE MUSCLE RELAXANTS ??? WEAKNESS.MYOPATHY AND (POST PARALYTIC SNDROME)

ACUTE RESPIRATORY FAILURE CRITERIA FOR EXTUBATION STABILITY OF THE PATIENT CLINICAL METABOLIC HEMODYNAMIC RESPIRATORY FUNCTION AND PARAMETERS AS NEAR TO NORMAL. OTHER PARAMETERS. WEANING FROM VENTILATOR ADJUSTED TO THE PATIENT CONDITION.SHORT TERM WEANING OR GRADUAL OVER DAYS.

ACUTE RESPIRATORY FAILURE Criteria for Extubation from Mechanical Ventilation STABILIZING ALL CLINICAL,METABOLIC AND HEMODYNAMIC PARAMETERS.