Effects of prolonged controlled mechanical ventilation on diaphragmatic function in healthy adult baboons
Effects of prolonged controlled mechanical ventilation on diaphragmatic function in healthy adult baboons
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DOI：
10.1097/00003246-199707000-00021
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发表时间：
1997-07-01
影响因子：
8.8
通讯作者：
Coalson, JJ
中科院分区：
文献类型：
--
作者：
Anzueto, A;Peters, JI;Coalson, JJ
目的：研究长时间机械通气后的肌力和耐力，设计：前瞻性动物研究，设置：动物研究实验室，受试者：7只未受伤的成年狒狒（Papio cynocephalus）用氯胺酮麻醉，镇静，麻痹和机械通气，用肺动脉和外周动脉导管监测动物，干预：机械通气11天，FIO2为0.21，潮气量为15 mL/kg。还监测了肺功能检查，包括肺容量、动脉血气和胸片。护理程序包括频繁翻身、胸部物理治疗，和气管内吸引，抗酸剂和预防性抗生素（静脉内青霉素、局部多粘菌素B和硫酸庆大霉素）。在三只动物中，在第0天和机械通气11天后，通过手术将鱼钩电极放置在两个膈神经周围，以进行神经刺激。在第0天，在进行膈神经刺激研究后移除电极。机械通气11天后，选择性处死动物并进行全面尸检。分别于通气前和通气后11 d每天测定血流动力学和肺功能指标，并于通气后0 d和11 d测定膈肌强度和耐力。通过吸气阻力负荷方案确定横膈膜耐力。在机械通气期间，血液动力学、肺容量或气体交换没有显著变化。在第7天，胸部X线照片显示6只动物的斑片状肺叶肺不张，除2只动物外，所有动物在第11天均消失。肺部病理学显示轻度局灶性肺炎。最大跨颅压较第0天下降25%，耐力下降36%。在健康狒狒中进行11天的机械通气和神经肌肉阻滞导致血流动力学、氧合和/或肺功能无显著变化，然而，观察到呼吸耐力和力量的显著损害。基于这些结果，很可能长时间的机械通气本身损害呼吸功能，而与潜在的肺部疾病无关。
Objective: To study diaphragmatic strength and endurance after a prolonged period of mechanical ventilation,Design: Prospective animal study,Setting: Animal research laboratory,Subjects: Seven uninjured adult baboons (Papio cynocephalus) were anesthetized with ketamine, sedated, paralyzed, and mechanically ventilated, Animals were monitored with pulmonary arterial and peripheral arterial catheters,Interventions: Mechanical Ventilation was provided for 11 days with an FIO2 of 0.21 and tidal Volume of 15 mL/kg, Pulmonary function tests, including lung volumes, arterial brood gases, and chest radiographs were also monitored, Nursing care procedures included frequent turning, chest physiotherapy, and endotracheal suction, Antacids and prophylactic antibiotics (intravenous penicillin, topical polymyxin B, and gentamicin sulfate) were administered, In three animals, fishhook electrodes were surgically placed around both phrenic nerves on both day 0 and after 11 days of mechanical ventilation for diaphragmatic stimulation, On day 0, the electrodes were removed after phrenic nerve stimulation studies were performed, After 11 days of mechanical ventilation, animals were electively killed and full autopsy performed.Measurements and Main Results: Hemodynamic and pulmonary function parameters were measured at baseline and every day during the 11 days of mechanical ventilation, Diaphragmatic strength and endurance were measured on days 0 and 11. Diaphragmatic endurance was determined by an inspiratory resistive loading protocol, There were no significant changes in hemodynamics, lung volumes, or gas exchange during the period of mechanical ventilation, On day 7,the chest radiographs showed patchy lobar atelectasis in six animals, which cleared by day 11 in ail but two of the animals, Lung pathology showed mild, focal pneumonitis, By day 11, maximum transdiaphragmatic pressure had decreased by 25% from day 0 and diaphragmatic endurance had decreased by 36%,Conclusions: Eleven days of mechanical ventilation and neuromuscular blockade in healthy baboons resulted in nonsignificant changes in hemodynamics, oxygenation, and/or lung function, However, significant impairment in diaphragmatic endurance and strength were seen, Based on these results, it is likely that prolonged mechanical ventilation by itself impairs diaphragmatic function independent of underlying lung disease.