Abstract
Introduction
The volume of intraoperative blood loss is measured and reported by OR nurses in many hospitals and doctors do not usually measure it by themselves. To measure intraoperative blood loss accurately is such a difficult task that many measurement errors occur due to various factors. However, it is important to obtain a more correct measurement for performing a safe operation and stable anesthesia control.
Case report
In total hip arthroplasty (THA) we had experienced massive intraoperative blood loss errors and later identified the two major causes of these errors.
One is the excess volume of infusions for irrigation infusions, and the other is the validity and reliability of the scales on infusion containers.
To accurately measure intraoperative blood loss, we should know these two important factors of intraoperative blood loss errors.
In arthroplasty we use many infusions for irrigation of the operative field. The labeled (nominal) volume of infusion containers do not accurately indicate the volume of infusions in the container. This is even defined by the WHO international pharmacopoeia (pharmaceutical laws), US, EU, and Japanese pharmacopoeia. According to these pharmacopoeia, the actual volume of infusions is (must be) not less than the labeled (nominal) volume. Moreover, the upper limit of excess volume is not regulated so far. This results in all parenteral infusions (i.e., I.V infusion bags, or bottles of saline) having excess volume compared to their respective labeled volumes.
We also have verified the accuracy of volume scales on the infusions bags and bottles and found out some products have inaccuracies that we cannot ignore.
After inquiring the pharmaceutical companies about the information concerning excess volume of infusions, we discovered that the excess volume is 2–5% higher than the labeled (nominal) volume depending on the product and company. (e.g., One product has around 3140ml in the container labeled 3000ml)
Discussion
Detailed information about excess volume of infusions is neither well recognized so far nor is it open to the public. Knowledge about the excess volume of infusions is necessary to acquire the accurate volume of intraoperative blood loss when using large volume of infusions (i.e., above 3 liters) for irrigating the field of operation. In these cases, excess volume in infusions can be large and cannot be ignored. Further investigation revealed intraoperative blood loss errors tend to be greater when irrigating Total Hip Arthroplasty (THA) compared to the Total Knee Arthroplasty (TKA).
A large error in the volume of intraoperative blood loss may affect the decision of whether or not to perform a blood transfusion.
Conclusions
This presentation highlights two causes of intraoperative blood loss errors; excess volume of infusions and the validity and reliability of scales on infusion containers. This information has not been shared in any known medical publications and has not been written so far on package inserts (i.e. attached document, Labeling, SmPC, interview form).
