Department of Critical Care Medicine, Zhongshan Hospital, Fudan University, No. 180 Fenglin Road, Xuhui District, Shanghai, 200032, China.
Department of Nursing, Zhongshan Hospital, Fudan University, No. 180 Fenglin Road, Xuhui District, Shanghai, 200032, China.
Nitric Oxide. 2021 May 1;109-110:26-32. doi: 10.1016/j.niox.2021.03.001. Epub 2021 Mar 3.
To assess the relationship between the intrapulmonary shunt and PaO/FiO in severe hypoxemic patients after acute type A aortic dissection (ATAAD) surgery and to evaluate the effect of inhaled nitric oxide (iNO) on intrapulmonary shunt.
Postoperative ATAAD patients with PaO/FiO ≤ 150 mmHg were enrolled. Intrapulmonary shunt was calculated from oxygen content of different sites (artery [CaO], mixed venous [CvO], and alveolar capillary [CcO]) using the Fick equation, where intrapulmonary shunt = (CcO-CaO)/(CcO-CvO). Related variables were measured at baseline (positive end expiratory pressure [PEEP] 5 cm HO), 30 min after increasing PEEP (PEEP 10 cm HO), 30 min after 5 ppm iNO therapy (PEEP 10 cm HO + iNO), and 30 min after decreasing PEEP (PEEP 5 cm HO + iNO).
A total of 20 patients were enrolled between April 2019 and December 2019. Intrapulmonary shunt and PaO/FiO were correlated in severe hypoxemic, postoperative ATAAD patients (adjusted R = 0.467, p < 0.001). A mixed model for repeated measures revealed that iNO, rather than increasing PEEP, significantly decreased the intrapulmonary shunt (by 15% at a PEEP of 5 cm HO and 16% at a PEEP of 10 cm HO, p < 0.001 each) and increased PaO/FiO (by 63% at a PEEP of 5 cm HO and 65% at a PEEP of 10 cm HO, p < 0.001 each). After iNO therapy, the decrement of intrapulmonary shunt and the increment of PaO/FiO were also correlated (adjusted R = 0.375, p < 0.001).
This study showed that intrapulmonary shunt and PaO/FiO were correlated in severe hypoxemic, postoperative ATAAD patients. Furthermore, iNO, rather than increasing PEEP, significantly decreased the intrapulmonary shunt to improve severe hypoxemic conditions.
评估急性 A 型主动脉夹层（ATAAD）手术后严重低氧血症患者的肺内分流与 PaO/FiO 的关系，并评估吸入一氧化氮（iNO）对肺内分流的影响。
纳入术后 PaO/FiO≤150mmHg 的 ATAAD 患者。采用 Fick 方程从不同部位的氧含量（动脉 [CaO]、混合静脉 [CvO] 和肺泡毛细血管 [CcO]）计算肺内分流，其中肺内分流=（CcO-CaO）/（CcO-CvO）。在基线（呼气末正压 5cmH2O [PEEP]）、增加 PEEP 30min 后（PEEP 10cmH2O）、5ppm iNO 治疗 30min 后（PEEP 10cmH2O+iNO）和降低 PEEP 30min 后（PEEP 5cmH2O+iNO）测量相关变量。
2019 年 4 月至 2019 年 12 月期间共纳入 20 例患者。严重低氧血症、术后 ATAAD 患者的肺内分流与 PaO/FiO 相关（调整后的 R=0.467，p<0.001）。重复测量混合模型显示，iNO 而非增加 PEEP 可显著降低肺内分流（PEEP 为 5cmH2O 时降低 15%，PEEP 为 10cmH2O 时降低 16%，均 p<0.001）并增加 PaO/FiO（PEEP 为 5cmH2O 时增加 63%，PEEP 为 10cmH2O 时增加 65%，均 p<0.001）。iNO 治疗后，肺内分流的减少与 PaO/FiO 的增加也呈相关（调整后的 R=0.375，p<0.001）。
本研究表明，严重低氧血症、术后 ATAAD 患者的肺内分流与 PaO/FiO 相关。此外，iNO 而非增加 PEEP 可显著降低肺内分流，从而改善严重低氧血症。
