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1、Mechanical Ventilation,Wuhan Union Hospital Sun Peng,Mechanical Ventilation is ventilation of the lungs by artificial means usually by a ventilator. A ventilator delivers gas to the lungs with either negative or positive pressure.,History of mechanical ventilation,The iron lung, also known as the Dr
2、inker and Shaw tank, was developed in 1929 and was one of the first negative-pressure machines used for long-term ventilation.,Negative-Pressure Ventilators,Early negative-pressure ventilators were known as “iron lungs.” The patients body was encased in an iron cylinder and negative pressure was gen
3、erated .,1940 Boston Chilrden Hospital Patiens suffered from the poliomyelitis,Iron Lung,Negative pressure ventilation,铁肺退出历史舞台？,1952年，哥本哈根HC Lassen和B Ibsen首次气 管切开，施行“正压通气”，以提供有效的氧合和二氧化碳排出 24小时内，为75名病人进行持续通气，他们动员 250 名医学生用手捏气囊，260 名护士参加床边护理，共消耗 250 筒氧气） 他们提出呼吸道管理基本原则： 保持呼吸道通畅，湿化，防止氧分压过高等，病死率从80% 降至2
4、5%,The design of the modern positive-pressure ventilators were based mainly on technical developments by the military during World War II to supply oxygen to fighter pilots in high altitude,Positive pressure ventilation,无创通气和负压通气再受重视,负压通气机如胸甲式及胸腹雨披式等呼吸机的研究取得了一定进展 无创通气和负压通气更符合自然及生理状况，它代表了呼吸机的发展趋势和方向,
5、无创（正压）机械通气的意义,1.实现了机械通气的“早期应用” 2.减少人工气道的并发症 3.在单纯氧疗与有创通气之间，提供了“过渡性”的辅助通气选择 4.作为一种短时或间歇的辅助通气方法扩展了机械通气的应用领域 5. 形成了有创与无创通气相互配合的机械通气新时代，提高了呼吸衰竭救治的成功率,Overview of topics,Indications Modes Advantages and disadvantages between modes Guidelines in the initiation of mechanical ventilation Common trouble shoo
6、ting examples with mechanical ventilation,Purposes:,To maintain or improve ventilation, & tissue oxygenation. To decrease the work of breathing & improve patients comfort.,Initiation of Mechanical Ventilation,Indications Indications for Ventilatory Support Acute Respiratory Failure Prophylactic Vent
7、ilatory Support Hyperventilation Therapy,Initiation of Mechanical Ventilation,Indications Acute Respiratory Failure (ARF) Respiratory activity is inadequate or is insufficient to maintain adequate oxygen uptake and carbon dioxide clearance. Inability of a patient to maintain arterial PaO2, PaCO2, an
8、d pH acceptable levels PaO2 0.6 (PaO2/FiO2 50mm Hg and rising pH 7.25 and lower,Initiation of Mechanical Ventilation,Indications Acute Respiratory Failure (ARF) Hypoxic lung failure (Type I) Ventilation/perfusion mismatch Diffusion defect Right-to-left shunt Alveolar hypoventilation Decreased inspir
9、ed oxygen Acute life-threatening or vital organ-threatening tissue hypoxia,Initiation of Mechanical Ventilation,Indications Acute Respiratory Failure (ARF) Clinical Presentation of Severe Hypoxemia Tachypnea Dyspnea Central cyanosis Tachycardia Hypertension Irritability, confusion Loss of consciousn
10、ess Coma,Initiation of Mechanical Ventilation,Indications Acute Respiratory Failure (ARF) Acute Hypercapnic Respiratory Failure (Type II) CNS Disorders Reduced Drive To Breathe: depressant drugs, brain or brainstem lesions (stroke, trauma, tumors), hypothyroidism Increased Drive to Breathe: increase
11、d metabolic rate (CO2 production), metabolic acidosis, anxiety associated with dyspnea,Initiation of Mechanical Ventilation,Indications Acute Respiratory Failure (ARF) Acute Hypercapnic Respiratory Failure (Type II) Neuromuscular Disorders Paralytic Disorders: Myasthenia Gravis, Guillain-Barre, ALS,
12、 poliomyelitis, etc. Paralytic Drugs: Curare, nerve gas, succinylcholine, insecticides Drugs that affect neuromuscular transmission; calcium channel blockers, long-term adenocorticosteroids, etc. Impaired Muscle Function: electrolyte imbalance, malnutrition, chronic pulmonary disease, etc.,Initiatio
13、n of Mechanical Ventilation,Indications Acute Respiratory Failure (ARF) Acute Hypercapnic Respiratory Failure Increased Work of Breathing Pleural Occupying Lesions: pleural effusions, hemothorax, empyema, pneumothorax Chest Wall Deformities: flail chest, kyphoscoliosis, obesity Increased Airway Resi
14、stance: secretions, mucosal edema, bronchoconstriction, foreign body Lung Tissue Involvement: interstitial pulmonary fibrotic diseases,Initiation of Mechanical Ventilation,Indications Acute Respiratory Failure (ARF) Acute Hypercapnic Respiratory Failure Increased Work of Breathing (cont.) Lung Tissu
15、e Involvement: interstitial pulmonary fibrotic diseases, aspiration, ARDS, cardiogenic PE, drug induced PE Pulmonary Vascular Problems: pulmonary thromboembolism, pulmonary vascular damage Dynamic Hyperinflation (air trapping) Postoperative Pulmonary Complications,Initiation of Mechanical Ventilatio
16、n,Indications Acute Respiratory Failure (ARF) Clinical Presentation of Hypercapnia Tachypnea Dyspnea Tachycardia Hypertension Headache (hallucinations when severe) Confusion (loss of consciousness, even coma when severe) Sweating,Initiation of Mechanical Ventilation,Hyperventilation Therapy Ventilat
17、ory support is instituted to control and manipulate PaCO2 to lower than normal levels Acute head injury,Initiation of Mechanical Ventilation,Contraindications Untreated pneumothorax Relative Contraindications Patients informed consent Medical futility Reduction or termination of patient pain and suffering,
