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目的本文旨在探讨功能性单心室患儿双向腔静脉肺动脉吻合术(BCPA)术后不同潮气量时脑血流的变化,以探究BCPA术后机械通气时改善氧合情况的方法。方法入选21例功能性单心室BCPA术后早期患儿,以随机顺序进行10ml/kg(PCV1)和15ml/kg(PCV2)压力控制通气,分别记录每个步骤的血流动力学指标、血气分析、呼吸力学指标和经颅多普勒超声情况。结果 21例完成研究患儿平均月龄为(13.8±10.0)个月,平均体重为(8.0±2.2)kg,体外循环时间(63.0±25.7)min,平均机械通气时间为(6.6±1.5)h,无再插管发生。两种潮气量下患儿心率、血压维持稳定,大潮气量(PCV2)与小潮气量(PCV1)相比,CVP高[(15.65±3.81)mmHgvs.(14.75±4.10)mmHg,P=0.001]、气道压力高[PIP为(15.90±3.91)cmH2Ovs.(11.32±3.70)cmH2O,P<0.001;MAP为(6.44±2.09)cmH2Ovs.(4.21±1.78)cmH2O,P<0.001]、二氧化碳分压[(33.46±5.52)mmHgvs.(39.34±7.20)mmHg,P<0.001]和氧分压[(42.31±7.90)mmHgvs.(47.48±7.66)mmHg,P<0.001]低、大脑中动脉血流[Vs为(96.55±28.33)m/svs.(101.84±24.91)m/s,P=0.029;Vd为(26.66±9.68)m/svs.(32.21±11.30)m/s,P<0.001;Vm为(50.08±16.47)m/svs.(53.79±16.31)m/s,P=0.042]降低、脑循环阻力(PI为1.46±0.21vs.1.27±0.31,P<0.001)增加,差异均有统计学意义。结论功能性单心室行BCPA术后,增加潮气量,轻度过度通气时,将导致脑循环阻力增加,脑循环血流减少,从而使肺循环血流量减少,可以导致BCPA术后患儿低氧血症,相反的,正常潮气量可以使患儿处于正常的氧合状态。
Objective To investigate the changes of cerebral blood flow in patients with functional single ventricle after biaxial venous pulmonary artery anastomosis (BCPA) with different tidal volume to explore the method of improving oxygenation after mechanical ventilation of BCPA. Methods Twenty-one patients with functional single ventricle BCPA were enrolled in this study. PCV1 and PCV2 pressure-controlled ventilation were randomized to record the hemodynamic parameters of each step. Blood gas analysis , Respiratory mechanics and transcranial Doppler ultrasound. Results The average age of 21 children who completed the study was (13.8 ± 10.0) months, the average body weight was (8.0 ± 2.2) kg, the duration of cardiopulmonary bypass was (63.0 ± 25.7) min and the mean duration of mechanical ventilation was (6.6 ± 1.5) h , No further intubation occurred. In both tidal volumes, heart rate and blood pressure remained stable. CVV was significantly higher in PCV2 than in PCV1 [(15.65 ± 3.81) mmHg vs (14.75 ± 4.10) mmHg, P = 0.001] (P <0.05). The PIP was (15.90 ± 3.91) cmH2O vs (11.32 ± 3.70) cmH2O, P <0.001; MAP was 6.44 ± 2.09 cmH2O vs 4.21 ± 1.78 cmH2O, P <0.001] and oxygen partial pressure [(42.31 ± 7.90) mmHg vs (47.48 ± 7.66) mmHg, P <0.001], while middle cerebral artery blood flow (96.55 ± 28.33) m / s (101.84 ± 24.91) m / s, P = 0.029; Vd was (26.66 ± 9.68) m / s vs (53.79 ± 16.31) m / s, P = 0.042], the resistance of cerebral circulation increased (PI = 1.46 ± 0.21vs.1.27 ± 0.31, P <0.001), the differences were statistically significant. Conclusions The functional single ventricle after BCPA increases the tidal volume and mild hyperventilation, which leads to the increase of cerebral circulation resistance and the reduction of cerebral blood flow, which leads to the decrease of pulmonary blood flow, which can lead to hypoxemia On the contrary, normal tidal volume can make children in normal oxygenation state.