Vidaur Loreto, Sirgo Gonzalo, Rodríguez Alejandro H, Rello Jordi
Critical Care Department, University Rovira and Virgili. Institut Pere Virgili, Joan XXIII University Hospital, Carrer Dr Mallafre Guasch 4, 43007 Tarragona, Spain.
Respir Care. 2005 Jul;50(7):965-74; discussion 974.
Management of ventilator-associated pneumonia needs to balance the avoidance of unnecessary antibiotic overuse with the provision of adequate initial empiric therapy. A clinical diagnosis based on new pulmonary opacity and purulent respiratory secretions plus other signs of inflammation is valuable in screening for patients with suspected ventilator-associated pneumonia. A rational strategy starts with immediate initiation of adequate antibiotics and collection of respiratory secretions to evaluate the causative organism. As a minimum, an endotracheal aspirate with direct staining and quantitative cultures should be obtained. Overall, the need to choose adequate antibiotics correctly and expeditiously calls for the use of broad-spectrum antibiotics, but the choice should be narrowed quickly in the light of microbiologic information. However, some patients (those who develop an infection within 5 days of hospitalization, those without recent antibiotic exposure, and those without hospitalization in the past 3 months) are at low risk of infection by resistant organisms. In that subset, adequate initial selection could be a non-pseudomonal third-generation cephalosporin, since antibiotics should target usual community-acquired organisms in addition to some Enterobacteriaceae and Staphylococcus aureus. Coverage of methicillin-resistant S. aureus should be limited only to intensive care units with concomitant index cases and to patients under antibiotic exposure. Patients at risk of Pseudomonas aeruginosa (e.g., 1 week of prior hospitalization or chronic obstructive pulmonary disease) require initial use of a combination of piperacilin/tazobactam and ciprofloxacin, or amikacin plus imipenem, meropenem, or an antipseudomonal cephalosporin. If risk of Acinetobacter baumannii exists, one of these agents should be a carbapenem. After 48 hours of therapy, each patient should be re-evaluated based mainly on resolution of hypoxemia and fever plus the initial microbiologic information. Whereas broad-spectrum therapy is initially warranted in many patients, this treatment may be narrowed considerably as culture results identify the causative organism and its sensitivity. Recent data suggest that reducing overall treatment duration to a maximum of 1 week is safe, effective and is less likely to promote the growth of resistant organisms in patients who are clinically improving. Optimal management should be based on a strategy combining early high doses of an effective agent for a short period of time, which is then simplified in the light of microbiologic information.
呼吸机相关性肺炎的管理需要在避免不必要的抗生素过度使用与提供充分的初始经验性治疗之间取得平衡。基于新出现的肺部浸润影、脓性呼吸道分泌物以及其他炎症体征做出的临床诊断，对于筛查疑似呼吸机相关性肺炎的患者很有价值。合理的策略始于立即开始使用充分的抗生素，并采集呼吸道分泌物以评估致病微生物。至少应获取气管内吸出物进行直接染色和定量培养。总体而言，正确且迅速地选择充分的抗生素需要使用广谱抗生素，但应根据微生物学信息迅速缩小选择范围。然而，一些患者（住院5天内发生感染的患者、近期未接触过抗生素的患者以及过去3个月内未住院的患者）感染耐药菌的风险较低。在该亚组中，充分的初始选择可以是一种非假单胞菌属第三代头孢菌素，因为抗生素除了针对一些肠杆菌科细菌和金黄色葡萄球菌外，还应针对常见的社区获得性微生物。耐甲氧西林金黄色葡萄球菌的覆盖范围应仅限于有相关索引病例的重症监护病房以及正在接受抗生素治疗的患者。有铜绿假单胞菌感染风险的患者（例如，住院1周或患有慢性阻塞性肺疾病）初始需要联合使用哌拉西林/他唑巴坦和环丙沙星，或阿米卡星加亚胺培南、美罗培南或抗假单胞菌属头孢菌素。如果存在鲍曼不动杆菌感染风险，这些药物中的一种应是碳青霉烯类抗生素。治疗48小时后，应主要根据低氧血症和发热的缓解情况以及初始微生物学信息对每位患者进行重新评估。虽然许多患者最初需要进行广谱治疗，但随着培养结果确定致病微生物及其敏感性，这种治疗可能会大幅缩小范围。最近的数据表明，将总体治疗时间最多缩短至1周对临床症状正在改善的患者来说是安全、有效的，且不太可能促进耐药菌的生长。最佳管理应基于一种策略，即早期短时间内使用高剂量有效药物，然后根据微生物学信息进行简化。
