神经调节辅助通气（NAVA）或压力支持通气（PSV）在危重症患者自主呼吸试验中的应用：一项交叉试验。
Neurally Adjusted Ventilatory Assist (NAVA) or Pressure Support Ventilation (PSV) during spontaneous breathing trials in critically ill patients: a crossover trial.
机构信息
Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, São Paulo, SP, Brazil.
Biomedical Engineering Laboratory, Escola Politécnica da Universidade de Sao Paulo, São Paulo, SP, Brazil.
出版信息
BMC Pulm Med. 2017 Nov 7;17(1):139. doi: 10.1186/s12890-017-0484-5.
BACKGROUND
Neurally Adjusted Ventilatory Assist (NAVA) is a proportional ventilatory mode that uses the electrical activity of the diaphragm (EAdi) to offer ventilatory assistance in proportion to patient effort. NAVA has been increasingly used for critically ill patients, but it has not been evaluated during spontaneous breathing trials (SBT). We designed a pilot trial to assess the feasibility of using NAVA during SBTs, and to compare the breathing pattern and patient-ventilator asynchrony of NAVA with Pressure Support (PSV) during SBTs.
METHODS
We conducted a crossover trial in the ICU of a university hospital in Brazil and included mechanically ventilated patients considered ready to undergo an SBT on the day of the study. Patients underwent two SBTs in randomized order: 30 min in PSV of 5 cmHO or NAVA titrated to generate equivalent peak airway pressure (Paw), with a positive end-expiratory pressure of 5 cmHO. The ICU team, blinded to ventilatory mode, evaluated whether patients passed each SBT. We captured flow, Paw and electrical activity of the diaphragm (EAdi) from the ventilator and used it to calculate respiratory rate (RR), tidal volume (VT), and EAdi. Detection of asynchrony events used waveform analysis and we calculated the asynchrony index as the number of asynchrony events divided by the number of neural cycles.
RESULTS
We included 20 patients in the study. All patients passed the SBT in PSV, and three failed the SBT in NAVA. Five patients were reintubated and the extubation failure rate was 25% (95% CI 9-49%). Respiratory parameters were similar in the two modes: VT = 6.1 (5.5-6.5) mL/Kg in NAVA vs. 5.5 (4.8-6.1) mL/Kg in PSV (p = 0.076) and RR = 27 (17-30) rpm in NAVA vs. 26 (20-30) rpm in PSV, p = 0.55. NAVA reduced AI, with a median of 11.5% (4.2-19.7) compared to 24.3% (6.3-34.3) in PSV (p = 0.033).
CONCLUSIONS
NAVA reduces patient-ventilator asynchrony index and generates a respiratory pattern similar to PSV during SBTs. Patients considered ready for mechanical ventilation liberation may be submitted to an SBT in NAVA using the same objective criteria used for SBTs in PSV.
TRIAL REGISTRATION
ClinicalTrials.gov ( NCT01337271 ), registered April 12, 2011.
背景
神经调节辅助通气（NAVA）是一种比例通气模式，它使用膈肌的电活动（EAdi）来提供与患者努力成比例的通气辅助。NAVA 已越来越多地用于重症患者，但尚未在自主呼吸试验（SBT）中进行评估。我们设计了一项初步试验，以评估在 SBT 期间使用 NAVA 的可行性，并比较 SBT 期间 NAVA 与压力支持（PSV）的呼吸模式和患者-呼吸机不同步性。
方法
我们在巴西一家大学医院的 ICU 进行了一项交叉试验，并纳入了在研究当天被认为准备进行 SBT 的机械通气患者。患者以随机顺序进行两次 SBT：PSV 为 5 cmH2O 或 NAVA 滴定以产生等效的气道峰压（Paw），呼气末正压为 5 cmH2O。ICU 团队对通气模式进行了盲法评估，以确定患者是否通过了每项 SBT。我们从呼吸机捕获流量、Paw 和膈肌的电活动（EAdi），并使用它来计算呼吸频率（RR）、潮气量（VT）和 EAdi。使用波形分析检测不同步事件，并将不同步指数计算为不同步事件数与神经周期数之比。
结果
我们纳入了 20 名患者进行研究。所有患者均通过 PSV 的 SBT，3 名患者在 NAVA 的 SBT 中失败。5 名患者重新插管，拔管失败率为 25%（95%CI 9-49%）。两种模式的呼吸参数相似：NAVA 时的 VT=6.1（5.5-6.5）mL/kg 与 PSV 时的 5.5（4.8-6.1）mL/kg（p=0.076），RR=27（17-30）rpm 在 NAVA 时与 26（20-30）rpm 在 PSV 时，p=0.55。NAVA 降低了 AI，中位数为 11.5%（4.2-19.7），而 PSV 为 24.3%（6.3-34.3）（p=0.033）。
结论
NAVA 降低了患者-呼吸机不同步指数，并在 SBT 期间产生与 PSV 相似的呼吸模式。考虑到可进行机械通气撤离的患者可能会在 NAVA 中接受 SBT，并使用与 PSV 中 SBT 相同的客观标准。
试验注册
ClinicalTrials.gov（NCT01337271），于 2011 年 4 月 12 日注册。
Zotero 插件