摘要目的 观察应用跨肺压指导重症胰腺炎腹腔高压合并急性呼吸窘迫综合征(ARDS)机械通气患者呼吸机参数设置对患者气体交换、呼吸力学的影响.方法 观察2013年1至12月江苏省苏北人民医院重症医学科12例急性重症胰腺炎合并腹腔高压,且需行机械通气的早期ARDS患者(发病≤3d).监测跨肺压(Ptp),设置呼气末正压(PEEP),维持呼气末跨肺压(Ptp-e)在0～10 cmH2O(1 cmH2O =0.098 kPa),Vt维持在6～8 ml/kg,维持吸气末跨肺压(Ptp-i)＜25 cmH2O,观察呼吸力学、气体交换等变化.结果 随着腹腔压力增高,气道平台压(Pplat)增加,两者正相关(r2 =0.741 9,P＜0.05);胸壁顺应性(Ccw)降低,两者负相关(r2=0.722 2,P＜0.05),腹腔压力与Ptp-e和Ptp-i均无显著相关(分别为r2=0.090 6和r2=0.057 4,P＞0.05).根据跨肺压设置呼吸机参数,患者PEEP[(14.6±4.2) cmH2O比(8.3±2.0) cmH2O]和Ptp-e[(1.5 ±0.5) cmH2O比(-2.3±1.4)cmH2O]高于基础状态(P＜0.05),Ptp-i与基础状态比较差异无统计学意义(P＞0.05).Ptp-e和PEEP显著相关(r2=0.549,P＜0.05),与呼气末食道压显著相关(r2 =0.260,P＜0.05).Ptp-i和Pplat显著相关(r2 =0.523,P＜0.05),与吸气末食道压显著相关(r2=0.231,P＜0.05).Ptp-i与潮气量无相关(r2=0.052 4,P＞0.05).根据跨肺压设置呼吸机参数,患者肺静态顺应性较基础状态明显改善[(48.1±10.3) cmH2O比(25.7±6.4) cmH2O,P＜0.05],Ccw以及呼吸系统顺应性较基础状态相比无显著改变(P＞0.05);氧合指数(235±48)mmHg比(160±35) mmHg(1 mmHg =0.133 kPa)较基础状态显著升高(P＜0.05),死腔分数(0.48±0.07)比(0.59±0.06)明显低于基础状态(P＜0.05).结论 在重症胰腺炎腹高压合并ARDS患者中应用跨肺压指导呼吸机参数设置,既能促进塌陷肺泡复张,改善氧合指数、肺顺应性,减少死腔通气,还可以监测肺应力,避免肺泡过度膨胀,具有肺保护作用.

abstractsObjective To assess the effect of mehanical ventilation (MV) guided by transpulmonary pressure (Ptp) on respiratory mechanics and gas exchange in severe acute pancreatitis patient with intraabdominal hypertension.Methods Twelve severe acute pancreatitis patient with intraabdominal hypertension and acute respiratory distress syndrome (ARDS) underwent mechanical ventilation were involved from Jan to Dec 2013.PEEP levels were set to achieve a Ptp of 0 to 10 cm of water at end expiration.We also limited tidal volume to keep Ptp at less than 25 cm of water at end inspiration.Respiratory mechanics and gas-exchange were measured.Results Plat pressure (Pplat) increased and the compliance of chest wall (Ccw) decreased when intraabdominal pressure (IAP) increased.Pplat correlated with IAP positively (r2 =0.741 9, P ＜ 0.05) and Ccw correlated with IAP negtively (r2 =0.722 2, P ＜ 0.05), respectively.There were not corrletions between IAP and endexpiratory Ptp (Ptp-e) and end-inspiratory Ptp (Ptp-i) (P ＞ 0.05).Compared with baseline, after guiding MVwith Ptp, the Level of PEEP (14.6±4.2) cmH2O vs (8.3 ±2.0) cmH2O, and Ptp-e (1.5 ±0.5) cmH2O vs (-2.3 ± 1.4) cmH2O increased (P ＜0.05) and Ptp-i did not increase significantly (P ＞ 0.05).Ptp-e correlated with PEEP (r2 =0.549, P ＜0.05) and end-expiratory esophageal pressure (Pes-e) (r2 =0.260, P ＜ 0.05).Ptp-i correlated with Pplat (r2 =0.523, P ＜ 0.05) and end-inspiratory esophageal pressure (Pes-i) (r2 =0.231, P ＜0.05), but did not correlate with Tidal volume(VT) (r2 =0.052 4,P ＞0.05).Compared with baseline, lung compliance(CL) (48.1 ± 10.3) cmH2O vs (25.7 ±6.4) cmH2O and oxygenation index (PaO2/FiO2) (235 ± 48) mmHg vs(160 ± 35) mmHg improved obviously (P ＜ 0.05),dead space fraction (VD/VT) (0.48 ± 0.07) vs (0.59 ± 0.06) decreased (P ＜ 0.05), but Ccw and respiratory compliance(Cr) didn't improve (P ＞ 0.05).Conclusions Transpulmonary pressure-directed mechanical ventilation in ARDS secondary to severe acute pancreatitis patient with intraabdominal hypertension could not only recruit the collapsed alveoli, improve lung compliance, increase oxygenation index and decrease dead space ventilation but also monitor lung stress to avoid alveoli overinflation, which might be lung protective.