成比例辅助通气在呼吸机依赖极低出生体重儿中的临床应用

Clinical application of proportional assist ventilation in very low birth weight infants with ventilator dependence

目的比较成比例辅助通气模式(PAV)和传统辅/控通气模式(A/C)对呼吸机依赖极低出生体重儿的生理学和呼吸力学影响。方法 46例呼吸机依赖极低出生体重儿随机分为PAV组和A/C组(每组23例)。PAV组以脱逸法设置阻力卸载增益,A/C组按常规通气方法调节,连续通气治疗3 d。每日在早、中、晚3个时间段分别连续监测观察30 min,比较两组患儿动脉血气分析结果、血氧饱和度(SPO2)、心率、血压、呼吸频率(RR)、平均气道压(MAP)、吸气峰压(PIP)、呼吸末正压(PEEP)、潮气量(VT)、每分通气量(MV)及氧合指数(OI)等指标。结果血气分析指标中,PAV组PaO2、OI高于A/C组(均P<0.01),而pH、PaCO2、FiO2及SPO2两组差异无统计学意义(P>0.05);呼吸力学指标中,PAV组PIP、MAP低于A/C组(均P<0.01),而PEEP、VT、MV和RR两组相比差异无统计学意义(P>0.05);血流动力学指标中,PAV组收缩压、舒张压变异度均低于A/C组(均P<0.01),而两组的平均动脉压及心率差异无统计学意义(P>0.05)。结论对呼吸机依赖极低出生体重儿,较之A/C模式,PAV模式能以更低的气道压维持机体气体交换正常,改善氧合,人机协同性更好。

Objective To study the effect of proportional assist ventilation（PAV） on physiology and respiratory mechanics in very low birth weight（VLBW） infants with ventilator dependence by comparison with conventional assist/control（A/C） ventilation. Methods Forty-six infants with ventilator dependence were randomly divided into two groups according to the ventilation model： PAV（n=23） and A/C（n=23）.The gain of resistive and elastic unloading was set based on the runway method in the PAV group.Ventilation parameters were set based on the conventional method in the A/C group.Infants were observed for 30 minutes three times per day for three consecutive days.Arterial gas analysis results,transcutaneous saturation of oxygen（SPO2）,heart rate,blood pressure（BP）,respiratory rate（RR）,mean airway pressure（MAP）,peak inspiratory pressure（PIP）,tide volume（VT）,minute volume（MV） and oxygenation index（OI）,were compared between the two groups. Results Compared with the A/C group,PaO2 and OI in the PAV group were significantly higher while PIP and MAP were significantly lower.There were no significant differences in FiO2,SPO2,pH,PaCO2,PEEP,VT,MV and RR between the two groups.Although mean arterial blood pressure and heart rate in the PAV group were not different from the A/C group,beat-to-beat variabilities in systolic and diastolic arterial blood pressure were significantly lower in the PAV group than in the A/C group. Conclusions PAV may safely maintain gas exchange at lower airway pressures compared with A/C ventilation in VLBW infants.It can also improve oxygenation and infant-ventilator synchronization.