Habib R H
Department of Pediatrics, Mercy Children's Hospital at St Vincent Mercy Medical Center, Medical College of Ohio, Toledo 43608, USA.
Ann Biomed Eng. 2001 Nov;29(11):997-1008. doi: 10.1114/1.1415531.
Uncuffed tracheal tubes (TT) are used to intubate infants and children to avoid laryngotracheal tissue injury. The geometric mismatch resulting from such intubation limits the efficacy of mechanical ventilation, and reliability of derived respiratory mechanical properties. This study tested the hypotheses that (1) normal stresses applied to the cuff surface by leak flows during ventilation result in intracuff pressure (Pcuff) fluctuations proportionate to leak magnitudes, and (2) these fluctuations reach a steady minimum when cuff volume reaches a critical value (Vcrit) at which the TT-airway mismatch is removed. Physical model and piglet measurements showed that, during simultaneous cuff inflation and mechanical ventilation, Pcuff consisted of a leak-dependent (Pcuff,l) component that cycles with the ventilator superimposed on a ramp rise due to cuff inflation. The breath-to-breath peak Pcuff,l (max Pcuff,l) decreased as leak flows are reduced, and these were relatively greater for higher ventilator flows and when the load impedance is increased such as by disease. These results describe a reproducible method of TT cuff inflation that removes leaks without increased risk of laryngotracheal tissue injury. Moreover, inflation of the TT cuff more securely improved ventilation efficacy and allowed for accurate respiratory mechanics.
无套囊气管导管（TT）用于婴儿和儿童插管，以避免喉气管组织损伤。这种插管导致的几何不匹配限制了机械通气的效果以及所推导呼吸力学特性的可靠性。本研究检验了以下假设：（1）通气期间漏流施加于套囊表面的法向应力会导致套内压力（Pcuff）波动，其与漏流大小成比例；（2）当套囊容积达到临界值（Vcrit），此时气管导管与气道的不匹配消除，这些波动达到稳定最小值。物理模型和仔猪测量结果表明，在套囊充气和机械通气同时进行时，Pcuff由一个与漏流相关的分量（Pcuff,l）组成，该分量随呼吸机周期变化，并叠加在因套囊充气而产生的斜坡上升之上。随着漏流减少，逐次呼吸的Pcuff,l峰值（max Pcuff,l）降低，对于更高的呼吸机流量以及当负载阻抗增加（如疾病导致）时，这些峰值相对更大。这些结果描述了一种可重复的气管导管套囊充气方法，该方法可消除漏流，且不会增加喉气管组织损伤的风险。此外，气管导管套囊充气更可靠地提高了通气效果，并有助于准确测量呼吸力学。
