Raillard Mathieu, Mosing Martina, Raisis Anthea, Auckburally Adam, Borland Karla, Canfrán Susana, Downing Frances, García de Carellán Mateo Alejandra, MacFarlane Paul, McFadzean William, Merlin Tristan, Portier Karine, Robertson Josephine, Soares Joao Henrique Neves, Steblaj Barbara, Zoff Aurora, Levionnois Olivier L
School of Veterinary Medicine, College of Environmental and Life Sciences, Murdoch University, Murdoch, WA, Australia.
Clinical Department for Small Animals and Horses, Veterinary University Vienna, Vienna, Austria.
Front Vet Sci. 2024 Dec 4;11:1475401. doi: 10.3389/fvets.2024.1475401. eCollection 2024.
Spirometry devices, which are components of many anaesthesia machines, are commonly used to assess lung mechanics during anaesthesia. Spirometry calibration usually adheres to manufacturer recommendations without established guidelines. Although more accurate and less variable than inbuilt spirometry in certain General Electric anaesthesia ventilators, near-patient spirometry lacks adequate evaluation.
We assessed near-patient spirometers' performance using Pedi-lite and D-lite flow sensors. Certified 1 L calibration syringes were used on 67 monitors located in 14 veterinary hospitals. Three consecutive inspired and expired volume values displayed by the monitors for each volume of the calibration syringe were recorded. Volumes studied were 50, 100, 150, 250, 300 mL for Pedi-lite and 150, 300, 450, 500, 750 mL for D-lite. Measured and targeted volumes were averaged, agreement error calculated. Accuracy was assessed plotting agreement errors against calibration volumes. A linear mixed-effects model was used to obtain linear regression between the error and the calibration volume. Mean, differential and proportional bias, limits of agreement, claimed accuracy and 10% clinical tolerance were calculated and displayed. Differences among monitors were evaluated using the Friedman rank sum test, differences between inspired and expired volumes using the Wilcoxon signed-rank.
Inter-monitor variability for inspired and expired volume readings using both sensors was high; intra-monitor variability was low. The error magnitude was independent of volumes evaluated. Using Pedi-lite, only a minority of measurements met manufacturer's specification or a 10% clinical tolerance; both inspired and expired volumes were significantly underestimated. Using D-lite, superior performance was demonstrated for volumes between 300 and 750 mL (mean biases close to zero and the majority of measurements meeting manufacturer's specifications and clinical tolerance). The difference between measured inspired and expired volumes with both sensors was significant.
These results support caution when interpreting clinical measurements of lung volumes and mechanics in anaesthetised patients when using these sensors. This is particularly important in smaller patients where lung volumes are below 300 mL. Trends should be reliable.
肺活量测定装置是许多麻醉机的组成部分，常用于评估麻醉期间的肺力学。肺活量测定校准通常遵循制造商的建议，但没有既定的指南。尽管在某些通用电气麻醉呼吸机中，近患者肺活量测定比内置肺活量测定更准确且变化更小，但缺乏充分的评估。
我们使用Pedi-lite和D-lite流量传感器评估近患者肺活量计的性能。在14家兽医医院的67台监测仪上使用经认证的1升校准注射器。记录校准注射器每个容量下监测仪显示的三个连续吸气和呼气容量值。Pedi-lite研究的容量为50、100、150、250、300毫升，D-lite研究的容量为150、300、450、500、750毫升。对测量值和目标值求平均值，计算一致性误差。通过绘制一致性误差与校准容量的关系图来评估准确性。使用线性混合效应模型获得误差与校准容量之间的线性回归。计算并显示平均值、差异和比例偏差、一致性界限、声称的准确性和10%的临床耐受性。使用Friedman秩和检验评估监测仪之间的差异，使用Wilcoxon符号秩检验评估吸气和呼气容量之间的差异。
使用两种传感器时，监测仪之间吸气和呼气容量读数的变异性较高；监测仪内部的变异性较低。误差大小与评估的容量无关。使用Pedi-lite时，只有少数测量值符合制造商的规格或10%的临床耐受性；吸气和呼气容量均被显著低估。使用D-lite时，在300至750毫升的容量范围内表现出卓越性能（平均偏差接近零，大多数测量值符合制造商的规格和临床耐受性）。使用两种传感器时，测量的吸气和呼气容量之间的差异显著。
这些结果表明，在使用这些传感器解释麻醉患者肺容量和力学的临床测量结果时应谨慎。这在肺容量低于300毫升的较小患者中尤为重要。趋势应该是可靠的。
