Polese G, Massara A, Poggi R, Brandolese R, Brandi G, Rossi A
Service of Pneumotisiology, ULSS 25, Verona, Italy.
Intensive Care Med. 1995 Aug;21(8):682-6. doi: 10.1007/BF01711550.
To investigate whether a new flow-triggered (FT) system can reduce the patient's inspiratory effort compared to a traditional pressure-triggered (PT) system during weaning from mechanical ventilation.
Prospective study.
Intensive care unit of a General Hospital.
10 mechanically ventilated patients, without chronic airway disease, ready to wean.
Minute ventilation, breathing pattern, lung mechanics, inspiratory work of breathing (WI) and pressure time product (PTP) of Ppl were obtained in two conditions: 1) unsupported spontaneous breathing through the ventilator circuit (SB); 2) spontaneous breathing with continuous positive airway pressure set at 5 cmH2O (CPAP). Two triggering systems, namely PT and FT, were used in each condition.
Though there was no change in breathing pattern, minute ventilation, and lung mechanics, the magnitude of the inspiratory effort decreased significantly with FT compared to PT in both instances. The added resistance (total flow resistance minus pulmonary resistance) decreased by 37% on average when FT replaced PT. PTP decreased, on average, 27% and 15% during SB and CPAP, respectively, with FT compared to PT (p < 0.05). A similar significant decrease was observed in WI.
The new FT system, i.e. flow-by system, reduces the unintentional ventilatory workload upon the patients' inspiratory muscles compared to traditional PT system during weaning from mechanical ventilation.
研究在机械通气撤机过程中，与传统压力触发（PT）系统相比，新型流量触发（FT）系统是否能降低患者的吸气用力。
前瞻性研究。
一家综合医院的重症监护病房。
10例机械通气患者，无慢性气道疾病，准备撤机。
在两种情况下获取分钟通气量、呼吸模式、肺力学、吸气作功（WI）和胸膜腔内压的压力时间乘积（PTP）：1）通过呼吸机回路进行无辅助自主呼吸（SB）；2）设置气道持续正压为5 cmH₂O时的自主呼吸（CPAP）。在每种情况下使用两种触发系统，即PT和FT。
尽管呼吸模式、分钟通气量和肺力学没有变化，但与PT相比，在两种情况下FT均使吸气用力的幅度显著降低。当FT取代PT时，附加阻力（总流量阻力减去肺阻力）平均降低37%。与PT相比，在SB和CPAP期间，FT使PTP分别平均降低27%和15%（p<0.05）。WI也观察到类似的显著降低。
在机械通气撤机过程中，新型FT系统（即旁流式系统）与传统PT系统相比，可减轻患者吸气肌的无意通气负荷。
