How accurate is visual estimation of perioperative blood loss in adolescent idiopathic scoliosis surgery?

The aim of this study was to assess whether the visual estimation method for perioperative blood loss is accurate in adolescent idiopathic scoliosis surgery.

Sixty-five consecutive patients, who were operated on from 2012 to 2015 and had a diagnosis of AIS, were included into the study. Gender, age, preoperative weight and height, preoperative major curve magnitude and T5‒T12 kyphosis angles, the fusion level, and the time of surgery were recorded. Perioperative blood loss was estimated by the same anesthesiologist for all patients. Then, an experienced surgeon estimated the perioperative blood loss by a gravimetric method, and the results were compared.

Seventeen (26.2%) of the patients were male and 48 (73.8%) were female. The mean age was 15.8 ± 1.9. The mean height of the patients was 162.1 ± 8.9 cm and the mean weight was 52.6 ± 8.9 kg. The mean preoperative major curve magnitude and kyphosis angles were 49.5 ± 9.2 and 47.1 ± 12.7 respectively. The mean estimate of the surgeon was 1009 ± 404.5 ml and the mean estimate of the anesthesiologist was 434 ± 217.6 ml and the difference was statistically significant (p < 0.05). Moreover, if blood loss was high during the operation, the difference between the estimates of the surgeon and anesthesiologist was also higher.

Even in operations where most of the blood goes into a suction canister, such as for AIS, a visual estimation method is not accurate. A short training regarding optimizing the amount of blood contained in sponges that are not fully soaked may be sufficient to improve this method.