Determining the volume of toxic liquid ingestions in adults: accuracy of estimates by healthcare professionals and members of the public
- 9 January 2013
- journal article
- review article
- Published by Taylor & Francis Ltd in Clinical Toxicology
- Vol. 51 (2), 77-82
- https://doi.org/10.3109/15563650.2012.763135
Abstract
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.Keywords
This publication has 10 references indexed in Scilit:
- Estimate or calculate? How surgeons rate volumes and surfacesLangenbecks Archiv für Chirurgie, 2012
- 2010 Annual Report of the American Association of Poison Control Centers’ National Poison Data System (NPDS): 28th Annual ReportClinical Toxicology, 2011
- Observer accuracy and reproducibility of visual estimation of blood loss in obstetrics: how accurate and consistent are health-care professionals?Archiv für Gynäkologie, 2009
- The Accuracy of Blood Loss Estimation After Simulated Vaginal DeliveryAnesthesia & Analgesia, 2007
- “About a cupful” – A prospective study into accuracy of volume estimation by medical and nursing staffAccident and Emergency Nursing, 2007
- Estimating Blood Loss: Can Teaching Significantly Improve Visual Estimation?Obstetrics & Gynecology, 2004
- Doctors and Nurses Estimation of the Weight of Patients: A Preventable Source of Systematic ErrorJournal of Toxicology: Clinical Toxicology, 2004
- Measuring a toddler's mouthful: Toxicologic considerationsThe Journal of Pediatrics, 2003
- STATISTICAL METHODS FOR ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENTThe Lancet, 1986
- The volume of a swallow: Correlation of deglutition with patient and container parametersThe American Journal of Emergency Medicine, 1983