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发表于 2012-2-19 15:27:21
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第3章 吸入性肺炎与急性呼吸衰竭
1 Mendelson syndrome: It was first described acute chemical aspiration pneumonitis in 1946, and characteristic by immediate respiratory distress, bronchospasm (gastric acid irritation), cyanosis, tachycardia, and dyspnea, following with partial recovery, concluding with a final phase of gradual respiratory recovery. X film shows irregular mottled densities. The critical pH is 2.5 and maximal pulmonary damage is achieved pH value of 1.5. More than 25ml (0.4ml/kg) is thought to be at risk of the patient.
2 Emergency Surgery:
Wide-orogastric tube and squeeze the drainage bottle
Regional anesthesia whenever possible
Preoperative premediation: antacid, 30ml sodium citrate, anticholinergic agent (atropine or glycopyroolate), metoclopramide, H2-receptor antagonist or proton inhibitors
Sedative or awake intubation
Extubate when the patient is fully awake
Strategy for the patient aspired: Tilt the table to 30-degree head-down position, maintain cricoid pressure, suction, endotracheal tube and inflation of the cuff, orogastric tube, auscultation of the chest, beta2-agonist, blood-gas analysis, early application of PEEP.
3 ALI and ARDS: ARDS is the most severe form of ALI. ALI : PaO2/FiO2 <300mHg, ARDS :<200mmHg. ARDS: occur as a result of pulmonary injury arising primarily from the lung pathology or secondarily from extrapulmonary processes. These include multiple trauma, massive blood transfusion, septic shock, fat or air embolism, disseminated intravascular coagulation, aspiration pneumonitis, fluid overload, burns, smoke or gas inhalation, and viral and mycobacterial pneumonia. The following conditions are associated with ARDS: acute renal failure, oxygen toxicity, drug overdoes, radiation, immunosupression, neurogenic pulmonary edema, acute vasculitis, pancreatitis, cardioversion, cardiopulmonary bypass, and Goodpasture syndrome.
4 Protective-ventilation strategy in ARDS:
maintenance of lower inspiratory driving pressure (<20cm H2O above PEEP)
lower tidal volume (6ml/kg)
acceptance of permissive hypercapnia over higher airway pressure
sedative to improve patient-ventilator synchronization
judicious use of PEEP (5-10cmH2O)
5 Lung compliance: change in lung volue per unit change in tramural pressure gradient. Pulmonary compliance changes with ages, several disease states: ALI, ARDS, congestive heart failure, barotraumas, neuromuscular disease, obesity, and pregnancy.
6 PEEP: (positive end-expiratory pressure)
Cardiovascular effect: It depends on the severity of respiratory failure, and level of PEEP, intravascular volume, contractility of the heart, and the pulmonary vasculature.
Normal: It can decrease CO, cause pulmonary parenchymal overdistention (lung come in close contact with left ventricle, changing compliance and interfering with ventricular function), increase pulmonary pressure and resistance, resulting in right ventricular dilation, which causes an intraventricular septum shift toward the left ventricle. The leftward septal shift decrease left ventricular diastolic filling, resulting in decreased stroke volume and cardiac output.
Patient with respiratory failure, PEEP, up to optimum levels, increase or does not change cardiac output. In patients with left ventricular failure and filling pressure more than 18 mmHg, PEEP may increase cardiac output by increasing coronary arterial oxygen content, augmenting systolic function, or reducing venous return and reduced filling pressure.
二 英文单词
Cyanosis 发绀
Dyspnea 呼吸困难
Cricoid 环状软骨
glycopyroolate
esophageal sphincter食道括约肌
sodium citrate 枸橼酸钠
Goodpasture syndrome 肺出血综合征
Judicious 慎重
tramural pressure gradient 跨壁压力(alveolus and pleural space)
overdistention 过度充盈 |
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