Abstract

DE LA PENA SILVA, Ancizar Joaquín; PEREZ DELGADO, Rafael; YEPES BARRETO, Ismael  and  DE LA PENA MARTINEZ, Michael. Is visual estimation useful in determining the extent of perioperative haemorrhage? A study of correlation among anaesthetists of intermediate and high complexity hospitals in Cartagena, Colombia. Rev. colomb. anestesiol. [online]. 2014, vol.42, n.4, pp.247-254. ISSN 0120-3347.  https://doi.org/10.1016/j.rca.2014.04.003.

Introduction: Ensuring Safe Surgery is a problem of great interest in public health. Bleeding isone of the most significant predictors of intraoperative outcomes. Visual estimation is the most frequently practiced method, although it is imprecise and may over or underestimate blood loss. Objectives: To determine the correlation between visual estimation and the actual volume of blood soaked in surgical absorbent material, by a group of anaesthetists in the city of Cartagena. Also, to establish the determinants of the correlation between estimated and actual volumes in the perioperative period. Methods: Observational study designed to estimate the correlation between visual estimation of blood loss, using photographs of gauze pads and sponges impregnated with different volumes of blood, and the actual extent of perioperative bleeding. The study sample was drawn from members of the Bolivar Anaesthesia Society, including subjects with different levels of training and experience (41 anaesthetists, 15 residents). Each participant was requested to estimate the volume of blood content (ml) in gauze pads and surgical sponges impregnated with blood, based on high-resolution photographic images. To estimate the agreement coefficient the intraclass correlation was used, and to identify factors associated with the accuracy of the estimate, a logistic regression analysis was performed. The visual estimate was considered adequate when it differed less than 10% compared to the actual known volume. Results: The visual estimate was the method of choice used by 100% of the participants to determine the extent of perioperative bleeding. However, its correlation with the actual volume of blood is suboptimal and visual estimates of the same volume of blood by different subjects were very heterogeneous (ICC: 0.582, 95% CI 0.28-0.74). A tendency to overestimate bleeding among participants using visual estimation (65.2%) was observed. The logistic regression analysis identified the level of training (OR 1.76, 95% CI 1.04-2.969, P = 0.033) and volumes greater than 75 ml of whole fresh blood in the absorbent material (OR 1.55,95% CI 1.04-2.32, P = 0.029) as independent determinants of agreement. Conclusions: Visual estimation is suboptimal as a method for determining perioperative bleeding. The objective measurement must be the method of choice in this clinical setting.

Keywords : Blood loss; Surgical; Comparative study; Perioperative period; Methods.

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