比較肺再擴張術合併肺保護通氣策略於中重度急性呼吸窘迫症患者成效之差異

背景：急性呼吸窘迫症(Acute respiratory distress syndrome, ARDS)為一種肺部瀰漫性之發症反應，主要的病理特徵為肺泡塌陷，使肺容積減少及肺泡之氣體交換表面積下降，肺泡和肺間質液的積聚引起肺水腫，導致低血氧性之急性呼吸衰竭，臨床上主要是以肺保護性通氣策略(lung protective ventilation strategies, LPVS)為支持治療。目前針對低血氧症之呼氣末正壓的設定，尚未有清楚的定論，然而於肺保護通氣策略實施下，發展了肺再擴張術(Recruitment maneuvers, RM)之通氣技術。肺再擴張術是一種以遞增呼氣末正壓的方式打開塌陷的肺泡，避免肺泡再塌陷，以減少ARDS因肺塌陷所導致之低血氧症。研究目的：為探討肺再擴張術(RM)合併肺保護通氣策略(LPVS)對中重度ARDS患者成效之差異。方法：於台灣中部某醫院進行了一項前瞻性之隨機對照試驗，ARDS病人被隨機分為兩組，實驗組(RM+LPVS group)接受肺再擴張術合併肺保護通氣策略，對照組(LPVS group)則接受肺保護通氣策略的呼吸機治療。肺再擴張術是指在FiO2=100%的氧氣濃度及固定吸氣壓力(15cmH2O)下，呼氣末正壓從10cmH2O開始，每分鐘以5cmH2O之壓力進行遞增，直到尖峰吸氣壓達55cmH2O，同時監測動脈血氧，當動脈血氧分壓PaO2+PaCO2≧400mmHg時的壓力點，為最佳的呼氣末正壓。主要結果指標為第1天至第7天的氧合能力(PaO2/FiO2 ratio, PFR)、氧合指數(oxygenation index, OI)及肺擴張情形[肺部超音波得分(Lung ultrasound score, LUS)]。次要結果指標為呼吸機使用天數、在ICU停留的天數及ICU死亡率。結果：20位接受機械呼吸機支持的ARDS病人被納入研究，兩組各10位被隨機分配至實驗組(RM+LPVS組)及對照組(LPVS組)。兩組的基本人口統計學特徵相似。主要結果顯示，實驗組(RM+LPVS組)於肺再擴張術後，提升了氧合能力(287.3 vs 147.0, p = .000)並改善氧合指數(3.8 vs 14.8, p = .023)，相較於對照組(LPVS組)更為顯著，在肺擴張情形[肺部超音波得分(LUS)]也有改善的情形，兩組於研究第七天達顯著差異(19.9 vs 28.2, p = .012)。次要結果指出，兩組之呼吸機使用天數(29.1 vs 25.7, p = .748)與在ICU停留時間(33.8 vs 27.2, p = .588)無顯著差異，但實驗組的無使用呼吸器天數 (20.2 vs 1.4, p = .006)及無住ICU天數(18.8 vs 3.5, p = 029)有顯著增加，並減少ARDS病人28天死亡率(p = .002)及住ICU期間之死亡率(p = .000)。結論：肺再擴張術可提升ARDS病人的氧合能力、降低氧合指數及改善肺擴張情形，增加病人無使用呼吸器天數及無住ICU的天數，並減少28天死亡率及住ICU期間之死亡率。

Background: Acute Respiratory Distress Syndrome (ARDS) is a complex pulmonary condition characterized by alveolar collapse, reduced gas exchange, and accumulation of fluids in the lungs, leading to severe hypoxemic respiratory failure. Lung Protective Ventilation Strategies (LPVS) are the primary clinical support, but optimal Positive End-Expiratory Pressure (PEEP) settings for hypoxemia remain unclear. Recruitment Maneuvers (RM), a technique incrementally increasing PEEP to reopen collapsed alveoli and prevent re-collapse, has been developed alongside LPVS.Aim: This study aims to compare the effectiveness of combining RM with LPVS in patients with moderate to severe ARDS.Methods: A prospective, randomized controlled trial was conducted in a Central Taiwan hospital. ARDS patients were divided into an experimental group (RM + LPVS) and a control group (LPVS only). The method of RM refers to that under FiO2=100% oxygen concentration and fixed inspiratory pressure (15cmH2O), the PEEP starts from 10 cmH2O and increases at a pressure of 5 cmH2O every minute until the peak inspiratory pressure(PIP) reaches 55cmH2O, and the arterial blood oxygen is monitored at the same time. The pressure point when the partial pressure of arterial oxygen PaO2+PaCO2≧400mmHg is the best PEEP. Primary endpoints included oxygenation (PFR), oxygenation index (OI), and lung expansion (Lung Ultrasound Score, LUS) from day 1 to 7. Secondary outcomes were ventilator days, ICU stay length, and ICU mortality. Results:20 patients with ARDS who received mechanical ventilator support were included in the study. Two groups of 10 person in each group were randomly divided into an experimental group (RM + LPVS group) and a control group (LPVS group). The basic demographic characteristics of the two groups were similar. The primary outcome showed that the experimental group (RM + LPVS group) improved PFR(287.3 vs 147.0, p = .000) and OI (3.8 vs 14.8, p = .023)after recruitment maneuvers, more significant than the control group (LPVS group). There was also an improvement in the lung expansion, with a significant difference between the two groups on the seventh day of the study (19.9 vs 28.2, p = .012). The secondary results pointed out that there was no significant difference in the ventilator days(29.1 vs 25.7, p = .748) and the ICU length of stay (33.8 vs 27.2, p = .588) between the two groups, but the ventilator-free days (VFDs) (20.2 vs 1.4, p = .006)and ICU-free days(18.8 vs 3.5, p = 029) in the experimental group were significantly increased, and the 28-day mortality rate ( p = .002) and ICU mortality rate ( p = .000) of ARDS patients were reduced.Conclusion:RM significantly improves PFR, reduces OI, and enhances lung expansion in ARDS patients. It also increases ventilator-free and ICU-free days and decreases mortality rates.