【正文】 demonstrating severe instability during tidal ventilation. 第三十三頁，共五十六頁。 肺泡穩(wěn)定性 (IE△ )的變化 Figure 2. Alveolar stability assessed by subtracting the area of the alveolus at inspiration (I) from that at expiration (E) using puter image analysis. The higher the IE, the more unstable the alveoli. Normal alveoli (control) are very stable. Tween lavage deactivates surfactant and causes alveolar instability (5 mins). Without additional positive endexpiratory pressure (PEEP), alveoli remain significantly unstable for 180 mins (TWEEN). Increasing PEEP (TWEEN PEEP) rapidly stabilizes alveoli. from Am J Respir Crit Care Med (30) 第三十四頁，共五十六頁。 正常的肺和由高 PIP/低 PEEP引起的 VILI 〔 PI標(biāo)記的損傷的肺泡細(xì)胞〕 Am J Respir Crit Care Med (38).) Figure . Confocal images of subpleural alveoli (top, control and injury). Red nuclei (propidium iodide [PI]) mark the injured cells (top, injury). Bar graph, mean number of PIpositive cells per alveolus。 mL/kg, tidal volume。 ZEEP, 0 positive endexpiratory pressure。 PEEP, positive endexpiratory pressure. 第三十五頁，共五十六頁。 高潮氣量 /低氣道壓 Figure 4. Left panel, rat lung ventilated with high tidal volume–low airway pressure for 20 mins. A type II epithelial cell (PII) is intact, whereas a type I epithelial cell is injured (arrows). The basement membrane is denuded (arrows) and lined with cell debris and fibrinous deposits (hyaline membranes). AS, alveolar space, ., interstitial edema。 ca, capillary lumen (original magnification 7,100). Right panel, highpressure ventilation plus positive endexpiratory pressure. Type I cells are intact (arrows) with the only pathology being endothelial blebs. En, endothelial cell。 PII, original magnification, 7,100). (Reproduced with permission from Am J Respir Crit Care Med (39).) David Carney, MD。 Crit Care Med 2024 Vol. 33. No. 3(suppl) 高氣道壓 +PEEP 第三十六頁，共五十六頁。 正常的肺泡 Am J Respir Crit Care Med (41).) Figure 5. Laser confocal images of normal (left) and edematous (right) subpleural alveoli in a rat. Normal airfilled alveoli on the left and edema (solid white) filled alveoli on the right. ARDS的肺泡 第三十七頁，共五十六頁。 剪切力造成細(xì)胞變形和肺損傷 Figure 6. Theoretical stresses imparted on epithelial cells during airway reopening. A, a collapsed pliant airway is forced open by a finger of air. Circles show how the stresses of reopening might affect epithelial cells. B, a fluidfilled narrow channel is cleared by a finger of air. Circles show how the stresses of fluid clearance might affect epithelial cells. from Am J Respir Crit Care Med (42).) 第三十八頁，共五十六頁。 RM和 PEEP對肺泡容積和肺穩(wěn)定性的影響 Figure 7. Alveolar number ( Alveoli/Field) and alveolar stability (IE) before (before RM), during (during RM), and after a recruitment maneuver (RM) with either 5 (positive endexpiratory pressure [PEEP] 5 after RM) or 10 (PEEP 10 after RM) cm H2O PEEP added. Note that with only 5 cm H2O PEEP after RM (PEEP 5 after RM) that alveoli recollapse (fall in alveoli/field) and the alveoli that remain open were unstable (increased IE). Adding PEEP (PEEP 10 after RM) prevented both recollapse and instability. from Am J Respir Crit Care Med (29).) 第三十九頁，共五十六頁。 ? 一個外表活性物質(zhì)失活的 ARDS模型中肺泡的不穩(wěn)定性被直接的視覺化， ? 減低潮氣量可以有意義的改善肺泡的穩(wěn)定性， ? 穩(wěn)定的肺泡伴有 PEEP可顯著的減少肺損傷， ? 減少和防止肺泡的不穩(wěn)定性是肺保護的重要策略 第四十頁，共五十六頁。 常規(guī)呼吸機支持 CMV Figure 8. In vivo photomicrographs of subpleural alveoli in the rat after lung injury by saline lavage ventilated with either conventional mechanical ventilation (CMV) or highfrequency oscillatory ventilation (HFOV) using a diameter tracheal tube. With CMV, a group of alveoli are seen inflated during inspiration (dots) but collapse with expiration (arrows). Alveoli are very stable with HFOV during ventilation. The same alveolus is seen with HFOV at inflation and exhalation (dots). David Carney, MD