Blood Loss Estimation Using Surgical Swabs Visual Analogue�

Lucy Nyathika

Fredrick Wambu

Presentation Outline

• Background
• Objective
• Materials and Methods
• Results
• Discussions
• References

Background

• Estimating intraoperative blood loss is a daily Operating room occurrence-remains a difficult task
• Visual blood loss estimation-most common despite documented inaccuracy
•  Surgical swabs used to mop blood when not collected in the suction bottle
• Gravimetric method- weighing swabs (pre and post swab use)-feasible ,more accurate
• Health-care providers tend to underestimate the volume of postpartum blood loss by about 20-75%(FIGO-2025)

Objective

• A quality improvement project
• Aim-To develop a pictogram( analogue) that can be easily remembered by the operating team and used to estimate blood absorbed by surgical swabs .

Material and methods

• Near expired whole donated blood (Lab tested, negative for blood-borne diseases) (simulating operative bleeding)-
• Measured using a syringe and swabs supersaturated in a basin
• Determine the absorptive capacity of dry surgical swabs
• Determine the absorptive capacity of gauze wetted with saline and supersaturated as compared to dry surgical swabs
• Raytec swab (10x10 cm )
• Abdominal swabs/ packs (30cmX 30cm)
• Tonsillectomy swabs

Super saturation of abdominal swab with blood

Findings in swabs Absorptive capacity

Dry Swabs

• Increases the absorption capacity of blood
• One gram of dry weight equivalent to 1 ml of blood
• Fully soaked 150 g abdominal swab- 150 mls of blood
• Raytec -20mls fully soaked
• Tonsillectomy swab -10mls fully soaked

Wet Swabs in Saline –Squeezed

• Decreases absorption capacity by 33 %
• Fully squeezed abdominal swab
• Is fully saturated by 100 mls compared to dry by 150 mls

Plan- prepare visual pictogram

Discussion

• Blood loss during surgery remains a concern –surgical team
• Precise estimation critical- Under versus overestimation
• Visual estimation mostly used, least accurate -How to increase accuracy, reliability and reproducibility ?
• Under or over transfusion trigger
• Variations and wide error in estimation
• Saline wetted swabs reduce absorptive capacity by 33%
•  Visual analogues/pictograms and scenarios are a good methods for simulation/ teaching surgical teams

Limitations-quality improvement project

• Some error in estimation even when using such a visual analogue.
• Visual pictogram analogue will decrease the error but will not eliminate it.
• Analogue to be constructed by testing certain types of swabs commonly used in hospitals.

Conclusion

• Care when using visual blood loss estimation-High rate of inaccuracy
• Visual pictogram decreases the error when estimating blood that has been absorbed by surgical swabs.
• Can a pictorial guide improve operating room team accuracy, reliability and reproducibility in visual estimation of blood loss in the operating room
• Subjectivity inherent in visual estimation of blood loss,
• Simulation‐based training recommended - enhance accuracy and clinical responsiveness.

References

• Solon JG, Egan C, McNamara DA. Safe surgery: how accurate are we at predicting intra-operative blood loss? J Eval Clin Pract. 2013;19(1):100–5. doi: 10.1111/j.1365-2753.2011.01779.x.
• Quantitative Blood Loss in Obstetric Hemorrhage: ACOG COMMITTEE OPINION, Number 794.Obstet Gynecol, 134(6):e150-e156, 01 Dec 2019
• Observer accuracy and reproducibility of visual estimation of blood loss in obstetrics: how accurate and consistent are health-care professionals?

Yoong W, Karavolos S, Damodaram M, Madgwick K, Milestone N, Al-Habib A, Fakokunde A, Okolo S Arch Gynecol Obstet, 281(2):207-213, 12 May 2009

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