Chapman F W, Dziuban S W, Newell J C
Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590.
Ann Biomed Eng. 1989;17(3):279-87. doi: 10.1007/BF02368047.
The work of breathing and its division between the patient and the mechanical ventilator were studied during weaning of 5 post-operative surgical patients from Synchronized Intermittent Mandatory Ventilation. Work by the patient (WP) was estimated by integrating the product of flow and pressure over time during intervals when waveforms indicated patient effort; ventilator work (WV) was similarly estimated during positive pressure inspirations. The ratio of WP to the rate of work on the lungs (WL) increased progressively during weaning from 0.14 +/- 0.04 to 1.2 +/- 0.15 while WV/WL dropped from 1.31 +/- 0.08 to 0.13 +/- 0.11. Work on the lungs decreased during weaning. This was due in part to significant improvements in lung mechanics: resistance decreased from 9.9 +/- 0.9 to 6.1 +/- 1.6 cmH2O/1/s and compliance increased from 58 +/- 17 to 102 +/- 30 ml/cmH2O. The patient and ventilator work ratios, and the work of breathing quantify factors which may be directly useful to the clinician and to future systems to automate weaning.
在5例术后患者从同步间歇指令通气撤机过程中，对呼吸功及其在患者与机械通气机之间的分配情况进行了研究。通过在波形显示患者用力的时间段内对流量与压力的乘积随时间进行积分来估算患者的功（WP）；在正压吸气期间以类似方式估算通气机的功（WV）。在撤机过程中，WP与肺上的功（WL）之比从0.14±0.04逐渐增加至1.2±0.15，而WV/WL则从1.31±0.08降至0.13±0.11。撤机期间肺上的功减少。这部分归因于肺力学的显著改善：阻力从9.9±0.9降至6.1±1.6 cmH2O/1/s，顺应性从58±17增至102±30 ml/cmH2O。患者和通气机的功比以及呼吸功量化了一些因素，这些因素可能对临床医生以及未来实现自动撤机的系统具有直接的用处。
