Division of Respiratory Diseases and Tuberculosis, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand.
Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
BMC Pulm Med. 2021 Oct 2;21(1):310. doi: 10.1186/s12890-021-01680-7.
Rapid shallow breathing index (RSBI) is the most commonly used parameter for predicting weaning outcome. Measurement of RSBI by Wright spirometer (RSBI) is the standard method in routine clinical practice. Data specific to the accuracy and reliability of the RSBI value displayed by the ventilator (RSBI) are scarce. Accordingly, this study aimed to evaluate the association between the average value of RSBI at different time points and RSBI, and to assess the accuracy and reliability of these two RSBI measurement techniques.
This prospective cohort study included mechanically ventilated patients who were ready to wean. At the beginning of spontaneous breathing trial using the flow-by method, RSBI was measured by two different techniques at the same time, including: (1) Wright spirometer (breathing frequency/average tidal volume in 1 min) (RSBI), and (2) the values displayed on the ventilator at 0, 15, 30, 45, and 60 s (RSBI).
Forty-seven patients were enrolled. The RSBI value was significantly higher than the RSBI value for every comparison. According to Spearman's correlation coefficient (r) and intraclass correlation coefficient (ICC), the average value of RSBI from 5 time points (0, 15, 30, 45, and 60 s) showed the best correlation with the standard technique (r = 0.76 [P < 0.001], and ICC = 0.79 [95% CI 0.61-0.88], respectively). Bland-Altman plot also showed the best agreement between RSBI and the RSBI value averaged among 5 time points (mean difference - 17.1 breaths/min/L).
We found that the ventilator significantly overestimates the RSBI value compared to the standard technique by Wright spirometer. The average RSBI value among 5 time points (0, 15, 30, 45, and 60 s) was found to best correlate with RSBI.
快速浅呼吸指数（RSBI）是预测撤机结果最常用的参数。使用 Wright 肺量计（RSBI）测量 RSBI 是常规临床实践中的标准方法。关于通气机显示的 RSBI 值的准确性和可靠性的数据很少。因此，本研究旨在评估不同时间点的 RSBI 平均值与 RSBI 之间的相关性，并评估这两种 RSBI 测量技术的准确性和可靠性。
这是一项前瞻性队列研究，纳入了准备撤机的机械通气患者。在使用流量触发法进行自主呼吸试验开始时，同时使用两种不同的技术测量 RSBI，包括：（1）Wright 肺量计（呼吸频率/1 分钟内平均潮气量）（RSBI），以及（2）通气机上在 0、15、30、45 和 60 秒时显示的值（RSBI）。
共纳入 47 例患者。RSBI 值明显高于每个比较的 RSBI 值。根据 Spearman 相关系数（r）和组内相关系数（ICC），5 个时间点（0、15、30、45 和 60 秒）的 RSBI 平均值与标准技术相关性最好（r=0.76[P<0.001]，ICC=0.79[95%CI 0.61-0.88]）。Bland-Altman 图也显示了 RSBI 与 5 个时间点（0、15、30、45 和 60 秒）的 RSBI 平均值之间的最佳一致性（平均差异-17.1 次/分/L）。
与 Wright 肺量计标准技术相比，我们发现通气机显著高估了 RSBI 值。5 个时间点（0、15、30、45 和 60 秒）的 RSBI 平均值与 RSBI 相关性最好。
