动态压力-容量曲线在新生儿机械通气中的临床意义

Clinical significance of dynamic pressure-volume curve in neonatal mechanical ventilation

摘要:

目的：探讨动态压力容量曲线（动态P-V曲线）在新生儿机械通气中的变化特点，为临床呼吸机的合理使用和病情判断提供借鉴。方法：利用Stephanie呼吸机自动绘制动态P-V曲线，计算25例患儿在机械通气后1，24，48，72 h及撤机前曲线斜率,并同时记录每分钟通气量(MV)、平均气道压（Pmean）、吸入氧浓度（FiO2）；观察异常通气(人机对抗、气道部分及完全梗阻、气道漏气、气管导管脱出气道)时动态P-V曲线形态特点。结果：随着肺部病变的改善,曲线斜率、MV逐渐增高,动态P-V曲线向纵轴移动，Pmean、FiO2逐渐降低。机械通气1，24，48，72 h及撤机前曲线斜率分别为(0.76±0.53)，(0.81±0.55)，(1.05±0.48)，(1.10±0.42)，(1.13±0.37) mL/cmH2O，机械通气48，72 h及撤机前斜率与1 h比较，差异有显著性(P＜0.05或P＜0.01)。异常通气时动态P-V曲线形态均有异常改变。结论：机械通气时动态P-V曲线斜率逐渐增大、曲线向纵轴移动的趋势反映了肺部病变的改善，其形态变化对于判断异常通气有重要作用，有助于减少机械通气并发症。［中国当代儿科杂志，2009，11（7）：525-528］

Abstract:

OBJECTIVE: To study the characteristics and role of dynamic pressure-volume curve (P-V curve) in neonatal mechanical ventilation. METHODS: A dynamic P-V curve was automatically drawn by the Stephanie ventilator. The slope rate of dynamic P-V curve was measured in 25 neonates who received mechanical ventilation 1, 24, 48 and 72 hrs after ventilation and before weaning from ventilation. Minute-ventilation (MV), mean airway pressure (Pmean), and fraction of inspired oxygen (FiO2) were recorded. The patterns of dynamic P-V curve during abnormal ventilation (resistance to ventilator, part or complete airway obstruction, airway leaking and tracheal catheter exodus) were observed. RESULTS: With the improvement of pulmonary disease, the slope rate of P-V curve and MV increased, Pmean and FiO2 decreased, and the P-V curve shifted to the volume axle. The slope rate of curve 48 and 72 hrs after ventilation and before weaning from ventilation (1.05±0.48, 1.10±0.42 and 1.13±0.37 mL/cmH2O respectively) increased significantly compared with that 1 hr after ventilation (0.76±0.53 mL/cmH2O) (P<0.05 or 0.01). Abnormal ventilation led to abnormal appearance of dynamic P-V curve. CONCLUSIONS: The increasing slope rate of dynamic P-V curve and the curve shifting to volume axle in neonatal mechanical ventilation may be associated with the improvement of pulmonary disease. The appearance changes of the curve may be of value in the assessment of abnormal ventilation.［Chin J Contemp Pediatr, 2009, 11 (7):525-528］