Department of Anaesthesia and Perioperative Medicine, Groote Schuur Hospital and Faculty of Health Sciences, University of Cape Town, South Africa.
S Afr Med J. 2019 Feb 26;109(3):154-158. doi: 10.7196/SAMJ.2019.v109i3.13633.
Low-cost, portable fingertip pulse oximeters are widely available to health professionals and the public. They are often not tested to International Organization for Standardization standards, or only undergo accuracy studies in healthy volunteers under ideal laboratory conditions.
To pragmatically evaluate the agreement between one such device and a conventional bedside pulse oximeter in a clinical setting, in patients with varied comorbidities and skin pigmentations.
A single-centre equipment comparison study was conducted. Simultaneous measurements were obtained in 220 patients with both a Contec CMS50D Fingertip Pulse Oximeter and a Nihon Kohden Life Scope MU-631 RK conventional bedside monitor. Peripheral oxygen saturations (SpO2) and pulse rates were documented, and patients' skin tone was recorded using the Fitzpatrick scale. Data were assessed using a Bland-Altman analysis with bias, precision and limits of agreement (LOA) calculated with 95% confidence intervals (CIs). A priori acceptability for LOA was determined to be 3%, in keeping with international standards.
The mean difference (therefore bias) between the conventional and fingertip oximeters for all data was -0.55% (95% CI -0.73 - -0.36). Upper and lower limits of agreement were 2.16% (95% CI 1.84 - 2.47) and -3.25% (95% CI -3.56 - -2.94). Regression analysis demonstrated worsening agreement with decreasing SpO2. When samples were separated into 'normal' (SpO2≥93%) and 'hypoxaemic' (SpO2 <93%) groups, the normal range displayed acceptable agreement between the two oximeters (bias -0.20% with LOA 2.20 - -2.27), while the hypoxaemic group fell outside the study's a priori limits. Heart rate measurements had a mean difference of -0.43 bpm (LOA -5.61 - 4.76). The study was not powered to detect differences among the skin tones, but demonstrated no trend for this parameter to alter the SpO2measurements.
During normoxia, portable fingertip pulse oximeters are reliable indicators of SpO2and pulse rates in patients with various comorbidities in a pragmatic clinical context. However, they display worsening agreement with conventional pulse oximeters during hypoxaemia. Skin tones do not appear to affect measurements adversely.
低成本、便携式指尖脉搏血氧仪广泛应用于医疗专业人员和公众。它们通常未经过国际标准化组织标准的测试，或者仅在理想的实验室条件下对健康志愿者进行准确性研究。
在患有各种合并症和皮肤色素沉着的患者中，从实用的角度评估一种此类设备与常规床边脉搏血氧仪在临床环境中的一致性。
进行了一项单中心设备比较研究。在 220 名患者中同时使用康泰 CMS50D 指尖脉搏血氧仪和尼森科登 Life Scope MU-631RK 常规床边监测器进行了同时测量。记录外周血氧饱和度 (SpO2)和脉搏率，并使用 Fitzpatrick 量表记录患者的肤色。使用 Bland-Altman 分析评估数据，使用 95%置信区间 (CI) 计算偏差、精度和一致性界限 (LOA)。LOA 的可接受性预先确定为 3%，符合国际标准。
所有数据的常规指尖血氧仪之间的平均差异（因此为偏差）为-0.55%（95%CI -0.73 - -0.36）。上下限分别为 2.16%（95%CI 1.84 - 2.47）和-3.25%（95%CI -3.56 - -2.94）。回归分析表明，随着 SpO2 的降低，一致性变差。当将样本分为“正常”（SpO2≥93%）和“低氧血症”（SpO2 <93%）组时，两种血氧仪在正常范围内显示出可接受的一致性（偏差-0.20%，LOA 2.20- -2.27），而低氧血症组超出了研究的先验界限。心率测量的平均差异为-0.43 bpm（LOA -5.61 - 4.76）。该研究没有能力检测肤色之间的差异，但没有显示该参数改变 SpO2 测量值的趋势。
在正常氧合时，便携式指尖脉搏血氧仪是患有各种合并症的患者在实用临床环境中 SpO2 和脉搏率的可靠指标。然而，在低氧血症期间，它们与常规脉搏血氧仪的一致性变差。皮肤色调似乎不会对测量结果产生不利影响。
