Methodologic issues associated with secretion weight as a dependent variable in research using closed-system suction catheters.
Methodologic issues associated with secretion weight as a dependent variable in research using closed-system suction catheters.
复制标题
在使用封闭系统抽吸导管的研究中，与分泌物重量作为因变量相关的方法学问题。
DOI：
10.1097/00006199-200009000-00009
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发表时间：
2000
期刊：
影响因子：
2.5
通讯作者：
Steinfeld,Y
中科院分区：
文献类型：
--
作者：
Steuer,JD;Stone,KS;Nickel,J;Steinfeld,Y
背景：封闭系统吸引导管（CSSC）旨在消除气管内吸痰（ETS）过程中断开患者与呼吸机连接的需要。在NIH资助的一项研究的数据收集过程中，注意到当连接到患者身上30分钟时，CSSC和套管内部积聚了水分。由于CSSC没有断开，他们提出了独特的方法学问题有关的分泌物测量作为一个因变量在临床research.Objectives：描述一个有效的，可靠的，和实用的方法来衡量分泌物期间获得ETS使用CSSC;并确定CSSC的重量变化后，其附件30分钟的机械通气患者。称重后，将CSSC和痰收集器连接到机械通气成人的气管内导管上，并保持连接43分钟（30分钟使呼气末正压和氧合水平恢复正常，13分钟模拟另一项研究中使用的ETS程序的时间范围）。未发生ETS。CSSC和痰捕集器，然后删除和reweigh.Results：一个方便的样本包括50名成年人谁是危重病和机械通气。自变量包括潮气量、压力支持、体温和呼吸频率。因变量为CSSC的湿重，通过从方案后导管重量中减去方案前导管重量确定。所有导管的平均湿重为0.5142±0.1215 g。在37例患者的亚组中，测定了两个湿重（74对观察结果）。这些导管的平均湿重为0.54014±0.1404 g。配对湿重具有统计学差异（t= 2.433; df= 36; p= 0.02）。计算Pearson相关系数和β系数。虽然潮气量和压力支持高度相关（r= 0.678; p= 0.011），有没有其他统计学上显着associations.Conclusions：分泌物的量是一个共同的因变量在ETS的研究。在CSSC连接到患者和呼吸机的时间期间，来自呼吸机的加湿系统或患者的湿气积聚在CSSC中。该湿重实际上不是ETS期间回收的分泌物的一部分，不应在分泌物的实际重量中考虑。湿重的决定因素有待进一步研究。
Background:Closed-system suction catheters (CSSC) were designed to eliminate the need to disconnect the patient from the ventilator during endotracheal suctioning (ETS). During data collection on an NIH-funded study, it was noted that moisture accumulated on the inside of the CSSC and sleeve when attached to the patient for 30 minutes. Because CSSC are not disconnected, they present unique methodologic problems related to measurement of secretions as a dependent variable in clinical research.Objectives:To describe a valid, reliable, and practical method for weighing secretions obtained during ETS using a CSSC; and to determine the change in weight of a CSSC after its attachment for 30 minutes to a mechanically ventilated patient.Methods:After being weighed, a CSSC and sputum trap were attached to the endotracheal tube of a mechanically ventilated adult and remained attached for 43 minutes (30 minutes to allow positive end expiratory pressure and oxygenation levels to return to normal and 13 minutes to mimic the time frame for the ETS procedure used in another study). No ETS occurred. The CSSC and sputum trap were then removed and reweighed.Results:A convenience sample consisted of 50 adults who were critically ill and mechanically ventilated. Independent variables included tidal volume, pressure support, body temperature, and respiratory rate. The dependent variable was wet weight of the CSSC, determined by subtracting the preprotocol catheter weight from the postprotocol catheter weight. The mean wet weight for all catheters was 0.5142±0.1215 grams. In a subset of 37 patients, two wet weights (74 paired observations) were determined. The mean wet weight for these catheters was 0.54014±0.1404 grams. The paired wet weights were statistically different (t= 2.433; df= 36; p= 0.02). Pearson correlation coefficients and beta coefficients were computed. While tidal volume and pressure support were highly correlated (r= 0.678; p= 0.011), there were no other statistically significant associations.Conclusions:The amount of secretions is a common dependent variable in ETS research. During the time that CSSC are attached to the patient and ventilator, moisture from either the ventilator's humidification system or the patient accumulates in the CSSC. This wet weight is not actually part of the secretions retrieved during ETS and should not be considered in the actual weight of secretions. Further study on the determinants of wet weight is warranted.