Warren Alpert Medical School of Brown University, Providence, Rhode Island.
Yale University School of Medicine, New Haven, Connecticut.
Respir Care. 2019 May;64(5):590-594. doi: 10.4187/respcare.06331. Epub 2019 Jan 22.
Incentive spirometers were developed to facilitate sustained maximum inspiration. In addition to a slow-rising float that indicates volume displacement, the incentive spirometers includes a sensitive, rapid-fluttering flow indicator. Achieving the target inspiratory volume is believed to be the most important factor in successful incentive spirometers use. This investigation hypothesized that patients focus on the rapid fluttering of the flow indicator rather than volume float during incentive spirometers use. The effects of adjusting hand positioning to cover the flow indicator on inspiratory volumes were evaluated.
A randomized, prospective, counter-balanced crossover analysis of postoperative subjects was completed. In alternating assignment, the subjects were randomized to 1 of 2 study groups: (A) with the flow indicator covered first followed by the flow indicator standard exposed, and (B) with the flow indicator standard exposed first, followed by the flow indicator covered. The subjects were asked to perform 2 inhalations on their incentive spirometers in the first flow indicator condition: covered or the standard exposed. After a 2-min delay, the subjects were then asked to perform an additional 2 inhalations with the alternate flow indicator condition. The difference between mean inspiratory volumes under covered and standard exposed conditions was evaluated for all subjects, within and between groups.
A total of 42 subjects were evaluated. For all the subjects, there was a mean increase of 255.4 mL of inspired volume when the flow indicator was covered (1,869.0 vs 1,613.7 mL, < .001). For the subjects in group B who had their flow indicators covered after standard exposure, mean inspiratory volumes increased by 285.7 mL (1,613.1 vs 1,898.8 mL, = .009). For subjects in group A who had their flow indicator covered before standard exposure, their mean inspiratory volumes increased by 225.0 mL (1,614.3 vs 1839.3 mL, = .007) when covered. There was no significant difference between the mean increases across patients in groups A and B (225.0 vs 285.7 mL, = .63).
Covering the flow indicator during incentive spirometers significantly increased achieved inspiratory volumes. Increased volumes were generated, irrespective of flow indicator covering order, which strongly suggested that the covering effect was greater than any learning or condition order carry-over effects. Because achieving target inspiratory volumes is considered the most important factor in successful incentive spirometers use, these findings may have immediate applications for improving incentive spirometers protocols, patient education, and device design implications.
激励型肺活量计的设计目的是促进持续的最大吸气。除了指示容量位移的缓慢上升浮标外，激励型肺活量计还包括一个灵敏、快速飘动的流量指示器。实现目标吸气量被认为是成功使用激励型肺活量计的最重要因素。本研究假设患者在使用激励型肺活量计时关注流量指示器的快速飘动，而不是容量浮标。评估了调整手部位置以覆盖流量指示器对吸气量的影响。
对术后患者进行了一项随机、前瞻性、交叉平衡的分析。在交替分配中，患者被随机分配到 2 个研究组之一：（A）先覆盖流量指示器，然后再暴露流量指示器标准，（B）先暴露流量指示器标准，然后再覆盖流量指示器。要求患者在第一种流量指示器条件下进行 2 次激励型肺活量计吸气：覆盖或标准暴露。2 分钟后，患者在交替流量指示器条件下再进行 2 次吸气。评估所有受试者在覆盖和标准暴露条件下的平均吸气量差异，以及组内和组间差异。
共评估了 42 名患者。对于所有患者，当流量指示器被覆盖时，吸气量平均增加了 255.4 毫升（1869.0 与 1613.7 毫升，<0.001）。对于先暴露标准后覆盖流量指示器的组 B 患者，平均吸气量增加了 285.7 毫升（1613.1 与 1898.8 毫升，=0.009）。对于先覆盖流量指示器后暴露标准的组 A 患者，当覆盖时，其平均吸气量增加了 225.0 毫升（1614.3 与 1839.3 毫升，=0.007）。组 A 和组 B 患者的平均增加量之间没有显著差异（225.0 与 285.7 毫升，=0.63）。
在激励型肺活量计中覆盖流量指示器可显著增加吸气量。产生的增加量与流量指示器覆盖顺序无关，这强烈表明覆盖效应大于任何学习或条件顺序的影响。因为实现目标吸气量被认为是成功使用激励型肺活量计的最重要因素，这些发现可能会立即应用于改进激励型肺活量计方案、患者教育和设备设计。
