Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of China Medical University, Shenyang, China.
Division of Respiratory Care, Department of Cardiopulmonary Sciences, Rush University, Chicago, Illinois.
Respir Care. 2022 Jul;67(7):807-813. doi: 10.4187/respcare.09543. Epub 2022 Apr 26.
The effect of single- and dual-limb circuits on aerosol delivery during noninvasive ventilation (NIV) in adult models is unclear.
A noninvasive ventilator equipped with a single-limb circuit or an ICU ventilator equipped with a dual-limb circuit was connected to a simulated lung. Ventilator parameters were adjusted to maintain a tidal volume at ∼500 mL. Aerosol deposition with different placements of a vibrating mesh nebulizer and humidification conditions were compared. Additional experiments by using a non-vented mask or a vented mask were compared in the single-limb circuit only. Aerosol was collected by a disposable filter placed between the simulated lung and the head model (n = 3), and measured by ultraviolet spectrophotometry (276 nm).
The aerosol deposition varied between 4.12 ± 0.22% and 20.75 ± 0.95%. The greatest aerosol delivery during NIV when using a non-vented mask was found when a vibrating mesh nebulizer was placed between the mask and 15 cm from the exhalation port in the humidified single-limb circuit, and 15 cm from the Y-piece in the inspiratory limb of the humidified dual-limb circuit, and no significant difference of aerosol deposition was found between the two optimal positions (20.03 ± 1.48% vs 18.04 ± 0.93%, respectively; =.042). There was no difference of aerosol delivery in dry versus humidified circuits, except when a vibrating mesh nebulizer was placed at the humidifier inlet in a dual-limb circuit. When using a vented mask, the aerosol deposition was poor (6.56 ± 0.41 ∼ 8.02 ± 0.39%), regardless of vibrating mesh nebulizer positions and humidification types.
During NIV, the aerosol delivery was optimal when a vibrating mesh nebulizer was placed between the non-vented mask and 15 cm from the exhalation port in the single-limb circuit or 15 cm from the Y-piece in the inspiratory limb of the dual-limb circuit; no significant difference was found between the two optimal placements. Humidification had little effect on aerosol delivery. Aerosol delivery was poor in the single-limb circuit with a vented mask.
在成人模型中，无创通气（NIV）期间单肢和双肢回路对气溶胶输送的影响尚不清楚。
将配备单肢回路的无创呼吸机或配备双肢回路的 ICU 呼吸机连接到模拟肺。调整呼吸机参数以维持约 500 mL 的潮气量。比较不同位置的振动网孔雾化器和加湿条件下的气溶胶沉积。仅在单肢回路中比较使用非通风面罩或通风面罩的附加实验。气溶胶通过置于模拟肺和头部模型之间的一次性过滤器收集（n = 3），并通过紫外分光光度法（276nm）测量。
NIV 期间的气溶胶沉积量在 4.12 ± 0.22%至 20.75 ± 0.95%之间变化。当使用非通风面罩时，在加湿的单肢回路中，当振动网孔雾化器置于面罩和呼气口之间 15cm 处，并且在加湿的双肢回路的吸气支中距 Y 型件 15cm 处时，发现 NIV 期间气溶胶输送最大，并且在两个最佳位置之间未发现气溶胶沉积的显著差异（分别为 20.03 ± 1.48%和 18.04 ± 0.93%；P =.042）。除了在双肢回路中当振动网孔雾化器置于加湿器入口处时，干燥与加湿回路之间的气溶胶输送没有差异。当使用通风面罩时，气溶胶沉积很差（6.56 ± 0.41%~8.02 ± 0.39%），无论振动网孔雾化器位置和加湿类型如何。
在 NIV 期间，当振动网孔雾化器置于单肢回路中的非通风面罩和呼气口之间 15cm 处或双肢回路中的吸气支中的 Y 型件 15cm 处时，气溶胶输送最佳；在两个最佳位置之间未发现显著差异。加湿对气溶胶输送的影响不大。通风面罩在单肢回路中的气溶胶输送较差。
