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Explore this issue:August 2017
Total intravenous anesthesia (TIVA) is defined as induction and maintenance of general anesthesia using solely intravenous agents, which usually includes propofol and a short-acting opiate (e.g., fentanyl or remifentanil). Traditional inhalational anesthesia (IA) is maintenance of general anesthesia using inhalation agents (e.g., isoflurane or sevoflurane). Several studies have tried to assess the impact of TIVA in endoscopic sinus surgery (ESS) by evaluating the surgical field visibility score, mean arterial pressure, heart rate, operative time, and blood loss. Although some studies show TIVA reduces surgical blood loss when compared to traditional IA, other studies have shown no difference in blood loss. In our review, we will focus on the relationship between TIVA and intraoperative blood loss in ESS. Accurate measurements of estimated blood loss (EBL) in sinus surgery are difficult because of copious irrigation, blood lost to ingestion, and blood outside the surgical field. Furthermore, surgical time can affect EBL, such that blood loss at a constant rate would yield higher EBL for longer cases. To account for this, some studies calculate blood loss as a rate, yielding outcomes in blood loss per hour. Methods of calculating EBL vary between studies, but usually involve subtracting the volume of irrigation used from the total volume in the suction canisters. To obtain the blood loss rate, the EBL is divided by surgical time in hours.
Most studies conclude that TIVA does not significantly reduce blood loss in ESS, when compared to IA. The current literature supporting TIVA is limited to inconsistently controlled and reported studies. However, we should be cautious in stating that all types of TIVA do not offer reduction in blood loss. This caution is justified by the fact that there are different agents used in TIVA, which may affect EBL outcomes. Hence, further studies are required to address these issues. Furthermore, other factors such as nasal polyposis, severity of the inflammatory disease, mean heart rate, blood pressure control, patient positioning, warm irrigation, topical decongestion, and epinephrine injection may play a significant role in blood loss and may not have been rigorously controlled in these studies. However, based on the available evidence, it does not appear that TIVA anesthesia provides any appreciable reduction in intraoperative blood loss when compared to standard general anesthesia protocols (Laryngoscope. 2016;126:1961–1962).