linical Toxicology, Guy's and St Thomas' NHS Foundation Trust and King's Health Partners, London, UK.
Clin Toxicol (Phila). 2013 Feb;51(2):77-82. doi: 10.3109/15563650.2012.763135. Epub 2013 Jan 17.
Ingestion of toxic liquids is common, and the volume ingested is often important for clinical decision-making. However, the accuracy and interpretation of volume estimates in the context of toxicological exposures is poorly characterised in adult practice.
To inform the interpretation of volume estimates when expressed in forms commonly encountered in toxicological practice: (1) semi-quantitative volume descriptors, such as 'mouthfuls'; (2) quantitative self-estimates of ingestion volume, for example, millilitres; and (3) estimates of residual volume in containers.
In the first part of the study, 50 members of the public ingested water in response to requests to take a 'small mouthful', 'large gulp' and 'five mouthfuls'. They estimated the amount ingested, and actual volumes were measured. In part 2, 15 members of the public and 15 healthcare professionals estimated the volumes contained in 12 opaque and transparent bottles.
The mean age of participants in part 1 was 37 years, and in part 2 it was 34 years. The mean volume (95% prediction interval) of a 'small mouthful' was 43 (3-137) mL; 'large gulp', 77 (20-168) mL; and 'five mouthfuls', 157 (25-375) mL. The mean error (95% limits of agreement) for self-estimates of ingestion volume was an underestimate of - 52% (- 90% to + 124%). Volume contained in bottles was underestimated by - 5% (- 38% to + 27%). This varied according to the container type (mean difference: opaque, - 10%; transparent, - 1%; P < 0.01) and participant type (members of the public, - 8%; healthcare professionals, - 3%; P = 0.02).
Volume estimates derived from semi-quantitative descriptors are not a reliable basis for clinical decision-making. Self-estimates provided in a quantitative form are inaccurate and prone to underestimation. Estimates of residual volume in containers should be regarded as suspect if the container is opaque. Where clinical decisions hinge on the volume ingested, efforts should be made to quantify this using measurement.
摄入有毒液体很常见，摄入的量对于临床决策往往很重要。然而，在成人实践中，对于毒理学暴露情况下的容量估计的准确性和解释描述得很差。
为了在毒理学实践中常见的形式来解释容量估计：（1）半定量的容量描述符，例如“一口”；（2）自我估计的摄入容量，例如毫升；和（3）容器中残留容量的估计。
在研究的第一部分中，50 名公众根据要求服用“一小口”、“一大口”和“五口”来摄入水。他们估计摄入的量，并测量实际量。在第二部分中，15 名公众和 15 名医疗保健专业人员估计了 12 个不透明和透明瓶子中的容量。
第一部分参与者的平均年龄为 37 岁，第二部分参与者的平均年龄为 34 岁。“一小口”的平均量（95%预测区间）为 43（3-137）毫升；“一大口”为 77（20-168）毫升；“五口”为 157（25-375）毫升。自我估计的摄入量的平均误差（95%的一致性界限）是低估了-52%（-90%至+124%）。瓶子中包含的容量被低估了-5%（-38%至+27%）。这根据容器类型（平均差异：不透明，-10%；透明，-1%；P < 0.01）和参与者类型（公众，-8%；医疗保健专业人员，-3%；P = 0.02）而有所不同。
从半定量描述符得出的容量估计不是临床决策的可靠依据。以定量形式提供的自我估计是不准确的，容易被低估。如果容器不透明，容器中残留容量的估计应被视为可疑。如果临床决策取决于摄入的量，应努力使用测量来量化这一点。
