Sola A, Fariña D, Rodriguez S, Kurlat I
Division of Neonatology, Hospital de Pediatría J.P. Garrahan, Buenos Aires, Argentina.
Crit Care Med. 1992 Jun;20(6):778-81. doi: 10.1097/00003246-199206000-00014.
To establish if the pressure indicated in the manometer of an infant ventilator (IV 100B, Sechrist, Anaheim, CA) reflects the true pressure delivered to the proximal airway during mechanical ventilation in the neonatal ICU.
With approval of our Institutional Research Board, data were collected prospectively. Peak inspiratory pressure and end-expiratory pressure were measured at the "Y" piece of the breathing tubing. Pressure readings from the conventional ventilator's manometer were compared with simultaneously obtained measurements using an electronic monitor.
This study was conducted in a 45-bed neonatal ICU, admitting 700 to 750 newborns per year.
Twelve neonates who required mechanical ventilation were included in the study.
Specific interventions were not made by study design. Measurements routinely obtained were compared.
Two hundred seventy-five simultaneous measurements of peak inspiratory pressure and positive end-expiratory pressure were compared. Peak inspiratory pressure values were higher with the electronic monitor in 273 (99%) of 275 measurements and the mean of the differences between the electronic monitor and ventilator's manometer was statistically significant (p less than .001). For positive end-expiratory pressure measurements, values indicated by the electronic monitor were lower in 152 (55%) of 275 determinations, equal in 65 (23%), and higher in 58 (21%) determinations. Percent variations between methods ranged from 0% to 140% for peak inspiratory pressures and from 0% to 500% for positive end-expiratory pressure.
These data demonstrate that it is impossible to know the true pressure delivered to the proximal airway of a neonate during mechanical ventilation by observing the ventilator pressure manometer. The manometer readings consistently underestimate the true peak inspiratory pressure values and are very unpredictable regarding positive end-expiratory pressure values. These findings support the use of other methods to monitor the proximal airway pressure besides the ventilator's manometer in the neonatal ICU. Furthermore, mean airway pressure should not be calculated from the pressure readings obtained from the tested ventilator's manometer.
确定婴儿呼吸机（IV 100B，Sechrist，阿纳海姆，加利福尼亚州）压力计显示的压力是否反映新生儿重症监护病房（NICU）机械通气期间输送到近端气道的真实压力。
经机构研究委员会批准，前瞻性收集数据。在呼吸管道的“Y”形接头处测量吸气峰压和呼气末压力。将传统呼吸机压力计的压力读数与使用电子监测仪同时获得的测量值进行比较。
本研究在一家拥有45张床位的新生儿重症监护病房进行，每年收治700至750名新生儿。
12名需要机械通气的新生儿纳入研究。
根据研究设计未进行特定干预。对常规获得的测量值进行比较。
对275次吸气峰压和呼气末正压的同步测量值进行比较。在275次测量中的273次（99%），电子监测仪测得的吸气峰压值更高，电子监测仪与呼吸机压力计之间差异的平均值具有统计学意义（p<0.001）。对于呼气末正压测量，在275次测定中，电子监测仪显示的值在152次（55%）中较低，在65次（23%）中相等，在58次（21%）中较高。吸气峰压的方法间百分比差异范围为0%至140%，呼气末正压为0%至500%。
这些数据表明，在机械通气期间，通过观察呼吸机压力计无法得知输送到新生儿近端气道的真实压力。压力计读数始终低估真实的吸气峰压值，并且对于呼气末正压值非常不可预测。这些发现支持在新生儿重症监护病房中除使用呼吸机压力计外，还应采用其他方法监测近端气道压力。此外，平均气道压不应根据受试呼吸机压力计获得的压力读数来计算。
