Olarte Jose Luis, Gelvez Javier, Fakioglu Harun, Torbati Dan, Frazier Kendall S, Totapally Balagangadhar R, Raszynski Andre
Division of Critical Care Medicine, Miami Children's Hospital, FL, USA.
Crit Care Med. 2003 Mar;31(3):916-23. doi: 10.1097/01.CCM.0000053524.86705.05.
We compared tracheobronchial injury following short-term intratracheal pulmonary ventilation (ITPV) and conventional mechanical ventilation (CMV) in a healthy rabbit model. ITPV, a form of tracheal gas insufflation, has been shown to decrease deadspace ventilation and increase CO2 removal and therefore may reduce ventilator-induced lung injury.
Medical center laboratory.
Twenty-five rabbits.
Rabbits were randomly assigned to either ITPV or CMV (n = 15 and 10, respectively). Both groups were mechanically ventilated for 8 hrs at the same ventilator settings (FIO2, 0.4; rate, 30 breaths/min; flow, 4 L x min(-1); positive end-expiratory pressure, 4 cm H2O; tidal volume, 40 mL). Peak, mean, and end-expiratory carinal pressures, ITPV flow rate, and hemodynamic variables were continuously monitored. Tissue samples for histologic analysis were obtained postmortem from the trachea contiguous to the tip of the endotracheal tube, the distal trachea, the carina, and the main bronchus. The histologic sections were scored, in a single-blind fashion, for ciliary damage, ulceration, hemorrhage, overall inflammation, intraepithelial inflammatory infiltrate, and edema.
ITPV was associated with significantly lower Paco and deadspace ventilation ratio than CMV. The combined tracheobronchial injury scores for all samples were significantly higher in the ITPV group compared with the CMV group (p <.005; Mann-Whitney U test). The ITPV injury scores, compared with CMV injury scores, were significantly higher at the carina and main bronchus (p <.01; Kruskal-Wallis test followed by Dunn's multiple comparison test). The area adjacent to the endotracheal tube showed the same degree of damage in both groups. Analysis of the injury scores in individual damage categories demonstrated the greatest difference in the ulceration category (p <.001).
In our study, ITPV, compared with CMV at the same minute ventilation, was associated with a significantly greater difference in tracheobronchial damage at the carina and main bronchus. We postulate that this difference may have been caused by the turbulence of the gas flow generated by the small-caliber ITPV catheter used in our neonatal-size animal model.
我们在健康兔模型中比较了短期气管内肺通气（ITPV）和传统机械通气（CMV）后的气管支气管损伤情况。ITPV作为一种气管气体吹入方式，已被证明可减少死腔通气并增加二氧化碳清除，因此可能减少呼吸机诱导的肺损伤。
医学中心实验室。
25只兔子。
兔子被随机分为ITPV组或CMV组（分别为n = 15只和10只）。两组均在相同的呼吸机设置下进行机械通气8小时（吸入氧分数，0.4；频率，30次/分钟；流量，4L×min⁻¹；呼气末正压，4cmH₂O；潮气量，40mL）。持续监测峰压、平均压和呼气末隆突压、ITPV流速及血流动力学变量。死后从气管插管尖端附近的气管、远端气管、隆突和主支气管获取组织样本用于组织学分析。组织学切片由单盲方式进行评分，评估指标包括纤毛损伤、溃疡、出血、总体炎症、上皮内炎性浸润和水肿。
与CMV相比，ITPV的动脉血二氧化碳分压和死腔通气比率显著更低。ITPV组所有样本的气管支气管损伤综合评分显著高于CMV组（p <.005；曼-惠特尼U检验）。与CMV损伤评分相比，ITPV在隆突和主支气管处的损伤评分显著更高（p <.01；Kruskal-Wallis检验，随后进行邓恩多重比较检验）。气管插管附近区域在两组中损伤程度相同。对各个损伤类别中的损伤评分分析显示，溃疡类别差异最大（p <.001）。
在我们的研究中，与相同分钟通气量的CMV相比，ITPV在隆突和主支气管处的气管支气管损伤差异显著更大。我们推测这种差异可能是由我们在新生动物模型中使用的小口径ITPV导管产生的气流湍流所致。
