PDF(Pubmed)
Abstract：
UNASSIGNED: Mechanical ventilation (MV) is an important life-saving method in the intensive care unit (ICU). A lower mechanical power (MP) is associated with a better MV strategy. However, traditional MP calculating methods are complicated, and algebraic formulas seem to be rather practical. The aim of the present study was to compare the accuracy and application of different algebraic formulas calculating MP.
UNASSIGNED: A lung simulator, TestChest, was used to simulate pulmonary compliance variations. Using the TestChest system software, the parameters, including compliance and airway resistance, were set to simulate various acute respiratory distress syndrome (ARDS) lungs. Ventilator was also set to volume- and pressure-controlled modes with various parameter values (respiratory rate, RR, time of inspiration, Tinsp, positive end-expiratory pressure, PEEP) to ventilate the simulated lung of ARDS (with various respiratory system compliance, Crs). For the lung simulator, resistance of airway (Raw) was fixed to 5 cmH2O/L/s. Crs below lower inflation point (LIP) or above upper inflation point (UIP) was set to 10 mL/cmH2O. The reference standard geometric method was calculated offline with a customized software. Three algebraic formulas for volume-controlled and three for pressure-controlled were used to calculate MP.
UNASSIGNED: The performances of the formulas were different, although the derived MP were significantly correlated with that derived from the reference method (R2>0.80, P<0.001). Under volume-controlled ventilation, medians of MP calculated with one equation was significantly lower than that with the reference method (P<0.001). Under pressure-controlled ventilation, median of MP calculated with two equations were significantly higher (P<0.001). The maximum difference was over 70% of the MP value calculated with the reference method.
UNASSIGNED: The algebraic formulas may introduce considerably large bias under the presented lung conditions, especially in moderate to severe ARDS. Cautious is required when selecting adequate algebraic formulas to calculate MP based on the formula\'s premises, ventilation mode, and patients\' status. In clinical practice, the trend rather than the value of MP calculated by formulas should require more attention.
UNASSIGNED: A lung simulator, TestChest, was used to simulate pulmonary compliance variations. Using the TestChest system software, the parameters, including compliance and airway resistance, were set to simulate various acute respiratory distress syndrome (ARDS) lungs. Ventilator was also set to volume- and pressure-controlled modes with various parameter values (respiratory rate, RR, time of inspiration, Tinsp, positive end-expiratory pressure, PEEP) to ventilate the simulated lung of ARDS (with various respiratory system compliance, Crs). For the lung simulator, resistance of airway (Raw) was fixed to 5 cmH2O/L/s. Crs below lower inflation point (LIP) or above upper inflation point (UIP) was set to 10 mL/cmH2O. The reference standard geometric method was calculated offline with a customized software. Three algebraic formulas for volume-controlled and three for pressure-controlled were used to calculate MP.
UNASSIGNED: The performances of the formulas were different, although the derived MP were significantly correlated with that derived from the reference method (R2>0.80, P<0.001). Under volume-controlled ventilation, medians of MP calculated with one equation was significantly lower than that with the reference method (P<0.001). Under pressure-controlled ventilation, median of MP calculated with two equations were significantly higher (P<0.001). The maximum difference was over 70% of the MP value calculated with the reference method.
UNASSIGNED: The algebraic formulas may introduce considerably large bias under the presented lung conditions, especially in moderate to severe ARDS. Cautious is required when selecting adequate algebraic formulas to calculate MP based on the formula\'s premises, ventilation mode, and patients\' status. In clinical practice, the trend rather than the value of MP calculated by formulas should require more attention.
摘要：
■机械通气（MV）是重症监护病房（ICU）中重要的挽救生命的方法。较低的机械功率(MP)与较好的MV策略相关联。然而,传统的MP计算方法复杂，代数公式似乎相当实用。本研究的目的是比较计算MP的不同代数公式的准确性和应用。
■肺部模拟器,TestChest,用于模拟肺顺应性变化。使用TestChest系统软件,参数，包括顺应性和气道阻力，被设置为模拟各种急性呼吸窘迫综合征(ARDS)肺部。呼吸机还设置为具有各种参数值(呼吸频率、RR,灵感的时间，Tinsp,呼气末正压,PEEP）对ARDS的模拟肺进行通气（具有各种呼吸系统顺应性，Crs).对于肺部模拟器，气道阻力（Raw）固定为5cmH2O/L/s。将低于下膨胀点(LIP)或高于上膨胀点(UIP)的Crs设定为10mL/cmH2O。参考标准几何方法用定制软件离线计算。使用三个用于体积控制的代数公式和三个用于压力控制的代数公式来计算MP。
■配方的性能不同，尽管衍生的MP与参考方法的MP显着相关（R2>0.80，P<0.001）。在容量控制的通风下，用一个方程计算的MP中位数显着低于参考方法（P<0.001）。在压力控制的通风下，用两个方程计算的MP中位数显著较高(P<0.001).最大差异超过用参考方法计算的MP值的70%。
■在所提出的肺部条件下，代数公式可能会引入相当大的偏差，尤其是中度至重度ARDS。在根据公式的前提选择适当的代数公式来计算MP时，需要谨慎。通风模式,和病人的状态。在临床实践中,趋势而不是由公式计算的MP值应该需要更多的关注。
■肺部模拟器,TestChest,用于模拟肺顺应性变化。使用TestChest系统软件,参数，包括顺应性和气道阻力，被设置为模拟各种急性呼吸窘迫综合征(ARDS)肺部。呼吸机还设置为具有各种参数值(呼吸频率、RR,灵感的时间，Tinsp,呼气末正压,PEEP）对ARDS的模拟肺进行通气（具有各种呼吸系统顺应性，Crs).对于肺部模拟器，气道阻力（Raw）固定为5cmH2O/L/s。将低于下膨胀点(LIP)或高于上膨胀点(UIP)的Crs设定为10mL/cmH2O。参考标准几何方法用定制软件离线计算。使用三个用于体积控制的代数公式和三个用于压力控制的代数公式来计算MP。
■配方的性能不同，尽管衍生的MP与参考方法的MP显着相关（R2>0.80，P<0.001）。在容量控制的通风下，用一个方程计算的MP中位数显着低于参考方法（P<0.001）。在压力控制的通风下，用两个方程计算的MP中位数显著较高(P<0.001).最大差异超过用参考方法计算的MP值的70%。
■在所提出的肺部条件下，代数公式可能会引入相当大的偏差，尤其是中度至重度ARDS。在根据公式的前提选择适当的代数公式来计算MP时，需要谨慎。通风模式,和病人的状态。在临床实践中,趋势而不是由公式计算的MP值应该需要更多的关注。
