几个单词理解的对吗？

Several comments and questions related to the conclusions of the work from Burnett et al. are appropriate. Pulse oximeter errors and bias can be caused by motion (shivering), interfering substances (carboxyhemoglobin, methemoglobin), mistiming of blood draws and oximeter readings, optical interference, probe misplacement, and low perfusion. In the case of low perfusion, reductions in the pulse oximeter signal are compounded by light absorption by melanin. In the study by Burnett et al., none of these factors were controlled. In addition, Black patients were older on average (62 vs. 52 yr) and had a greater incidence of kidney failure and diabetes than White patients. Could these disparities have contributed to lower perfusion, and amplified the calibration error? Further study is needed.

与Burnett等人的研究结论有若干相关、适当的注解和问题。脉氧仪误差和偏倚可由运动(颤抖)、干扰物质(羧基血红蛋白、高铁血红蛋白 )、抽血和血氧计读数的误时、光干扰、探头错位和低灌注引起。低灌注时，减少的脉氧仪信号还被黑色素对光的吸收而恶化。在Burnett等人的研究中，这些因素均未得到控制。此外，黑人患者平均年龄较大(62 vs.52岁)，肾衰竭和糖尿病的发生率高于白人患者。这些差异是否加重了低灌注，并放大了标定误差?需进一步研究。

controlled控制?对照？排除？