Anesthesia Duration Does Not Exist in a Surgical Vacuum

To the Editor Brady et al performed a novel retrospective investigation into outcomes after prolonged, otherwise intermediate-risk surgery. We take issue with the wording of their conclusion. From our perspective, they studied duration of surgery not anesthesia duration because it is for the prolonged surgery that prolonged anesthesia was administered. Obviously having a control group for similar surgery and similar duration without anesthesia would be practically impossible. One possible imaginary control group would be being anesthetized for a similarly prolonged number of hours without any surgery. From practical experience we can say with almost absolute certainty that the imaginary control group is very unlikely to see any complications. It is well established that perioperative entities like MINS (myocardial injury after noncardiac surgery) can affect mortality and outcome, especially after longer surgeries, from the extreme inflammation and prothrombogenic processes getting stimulated exits. Although the authors reported the incidence of myocardial infarction (MI), MINS is diagnosed using a high-sensitivity troponin assay, and most likely was not recorded in the National Surgical Quality Improvement Program database. Other studies have associated blood loss and blood transfusion with an increased risk of cardiac complications after surgery. In our experience, when we provide anesthesia for these patients it is often a vexing problem to maintain an adequate blood pressure for graft perfusion given the slow but persisting blood loss while simultaneously trying to avoid transfusion. To us, this is one more of the several studies showing that a prolonged surgical procedure, compounded by anesthesia and ongoing inflammatory processes may contribute to increased complications as observed in this study.