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发表于 2012-2-19 17:32:03
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第三章笔记
9 急性肺损伤的病理生理:hyaline membrane(透明膜), alveolar hemorrhage, increased
endothelial and epithelial permeability(内皮细胞和上皮细胞的通透性增加),neutrophilic infiltration(中性粒细胞浸润)
机制:Increased permeability→passage of protein-rich plasma both in the alveolar and in the interstitial spaces(间质)→ poor lung compliance and ineffective gas exchange
加上 alveolar surfactant content ↓
filled with fibrin and other cellular materials
最终 collagen(胶原) deposition and pulmonary fibrosis.
Complement activation(补体活化) may also play a major role
Cyclic opening and closing of these alveolar units has been implicated as a cause of
ventilator-induced lung injury
10 ARDS的PEEP设定
On a static pressure-volume curve, the determination of this lower inflexion point (LIP)(低位拐点) allows the clinician to set the positive end-expiratory pressure (PEEP) to 2 cm H2O above this critical opening volume to prevent alveolar collapse and promote recruitment.
The ideal tidal volume can be extracted from this exercise as the volume contained between the LIP and the UIP(高位拐点)
11 双相正压通气(BiPAP)
BiPAP is typically reserved for patients who are experiencing mild to moderate
respiratory failure and who are not at increased risk of aspiration
12 Rapid shallow breathing index =respiratory rate/tidal volume>200 breaths per
minute per L
13 关于机械通气支持
In patients with markedly increased work of breathing, hypervolemia(血容量过多), or impaired left ventricular pump function, the institution of mechanical ventilatory support can be life saving because of its ability to support the cardiovascular system, independent of any beneficial effects that mechanical ventilation may have on gas exchange. In patients with decreased pulmonary elastic recoil(弹性回缩力), increased pulmonary vascularresistance, hypovolemic, or airflow obstruction, the institution of mechanical ventilatory support may induce cardiovascular instability, which if not corrected can lead to total cardiovascular collapse.
When pulmonary compliance decreases, the transmission of airway pressure to intrathoracic pressure decreases
14 高氧损伤
Retrolental fibroplasia (retinopathy of prematurity(早产儿视网膜病变)) in the premature neonate has been reported after exposure to PaO2 at more than 80 to 150 mmHg for a few hours
the adult patient can generally tolerate 1 atmosphere of oxygen partial pressure for at least 24 hours.
bronchiolar and tracheal ciliated cells(气管支气管纤毛细胞) can be damaged by 80% to 100% oxygen
15 PEEP改善氧合的机制:
an increase in the FRC and redistribution of extravascular lung water
16 最佳PEEP
More recently, the endpoint for PEEP application is the lowest level of PEEP that provides an adequate PaO2 at an FIO2 of less than 0.5 |
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