Mechanical Ventilation •Ventilator-induced lung injury Remember that all MV is harmful to the lung and may cause “VILI”: 46 © OnCourse Learning Corporation 2015
MV proves beneficial by: Decreasing systemic or (myocardial oxygen consumption) MVO2 Reducing intracranial pressure 47 © OnCourse Learning Corporation 2015
Mechanical Ventilation Types of ventilators • Positive pressure - Inspiration created by positive pressure - Expiration passive - Classifications: pressure-cycled, volume cycled • Negative pressure ventilator: iron lung 48 © OnCourse Learning Corporation 2015
Goals of Mechanical Ventilation Most important goals of MV are: • Reduction in work of breathing • Assurance of patient comfort • Synchrony with ventilator • Adequacy of ventilation and oxygenation • Airway protection 49 © OnCourse Learning Corporation 2015
Improve Oxygenation PEEP: Physiologic 3-5 cm • Actions: improves the PaO 2 without increasing FiO 2 , decreases surface tension, decreases intrapulmonary shunt • Uses: ARDS (acute respiratory distress syndrome), acute respiratory failure • Adverse effects: hemodynamic changes (may decrease cardiac output), barotrauma, increased ICP 50 © OnCourse Learning Corporation 2015
Removal CO 2 Promoting improved alveolar ventilation • Increased frequency (f) • Increased tidal volume (Vt) • No change in dead space On the test, the answer should be to increase the frequency of respiratory rate to reduce CO 2 . 51 © OnCourse Learning Corporation 2015
Guidelines: Newly Intubated Patient • Ventilator mode: - Goals • Initial FiO 2 = 100%, then wean to keep sats above preset %. • Initial Vt 5-10ml/kg (ideal body weight: IBW): ARF may require more to satisfy air hunger, ARDS less • RR = Target pH and PaCO 2 • Add PEEP: diffuse lung injury and reduce FiO 2 52 © OnCourse Learning Corporation 2015
Assessment of Patient with Mechanical Ventilation Pulmonary assessment of intubated patient • Airway: type, size, position, cuff pressure • Chest excursion: bilateral and equal • Breath sounds: bilateral • Ventilatory mechanics: VC, Vt, RR • Ventilator parameters: mode, Vt, RR, FiO 2 , PEEP, PIP, MAP (mean airway pressure) alarms • Pulse oximetry, ABGs, CXR 53 © OnCourse Learning Corporation 2015
Assessment of Patient with Mechanical Ventilation • Cardiovascular - HR, rhythm (common dysrhythmia on ventilator is PACs and/or at fib), decreased BP, pulse pressure, hemodynamic parameters • Neurologic • Renal metabolic • GI (bowel sounds, abdominal distention) • Nutritional • Immunologic and psychological 54 © OnCourse Learning Corporation 2015
Complications on MV • Decreased cardiac output • Fluid retention • Baro-biotrauma • Atelectasis • Hypercapnia-hypo • Oxygen toxicity • Aspiration • GI effects • Infection • Asynchrony • Anxiety • Inability to wean 55 © OnCourse Learning Corporation 2015
Weaning From MV Improvement of pulmonary condition, such that gradual withdrawal of ventilatory support, is possible. Indications: NIF, VC, VT, RSBI (rapid shallow breathing index) • Resolution or improvement of condition •
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- Fall '19