Necrotizing Soft Tissue Infections and Intraoperative Management of Sepsis

Abstract

A 42-year-old female, 101kg, presented to the emergency department (ED) 1/2025 for bilateral (b/l) lower extremity (LE) necrotizing soft tissue infections (R > L) and necrosis of the buttocks. LE wounds started in 2020 and became painful in 12/2024, patient (pt) endorsed a sedentary lifestyle with frequent falls, otherwise denied any other past medical history. Pt was a poor historian. In the ED she received a 30 ml/kg bolus of crystalloid which failed to improve her blood pressure (BP). She was then started on a norepinephrine (NE) drip (gtt) at 5 mcg/min. CT scans of the pelvis and LEs revealed evidence of necrosis and soft tissue infections. Orthopedic and general surgery elected to perform urgent right disarticulation at the knee joint and gluteal debridement respectively. In the operating room (OR), an awake arterial line was placed followed by a post-induction/intubation central venous catheter (CVC). Other monitors included standard ASA monitors, 5 lead electrocardiogram (ECG), bispectral index (BIS), and foley catheter. Sevoflurane was used for maintenance of anesthesia titrated to BIS with goals of 40-60. NE titrated to mean arterial pressures (MAPs) with a goal of ≥65. Throughout the procedure, NE was gradually increased to 16 mcg/min, at that point a vasopressin gtt was also started at 0.03 units/min. Total fluid “ins & outs” included In: 2800 ml LR, 1000 ml NS, 1000 ml albumin, 1 unit pRBCs; (5.1L total in) and out: estimated blood loss 300 ml (200 ml for amputation, 100 ml for debridement), urine output 85 ml; (385 ml total out). Pt transported to PACU intubated on 50 mcg/hr fentanyl, 14 mcg/min NE, and 0.03 units/min vasopressin. Early recognition of sepsis and septic shock and prompt source control are crucial for the management of these critically ill pts and treatment is usually initiated before the pt reaches the OR. The pt was appropriately given 30 ml/kg of crystalloid in the ED and started on vasopressors when the pt’s BP failed to improve significantly. Antibiotic therapy was also initiated in the ED with clindamycin, linezolid, and piperacillin-tazobactam and was re-dosed in the OR. There is no evidence to support an increased benefit of one specific anesthetic technique i.e. inhalational vs intravenous in the setting of septic shock[1]. Pt was not a candidate for LE block due to the infected soft tissue. Pts in septic shock generally require less anesthetic, which is why we elected to utilize a BIS to ensure appropriate depth of anesthesia. Intraop, maintaining organ perfusion pressures is critical with fluid and vasopressors with MAP goals ≥65[1]. Special care should be applied so as not to induce coagulopathy due to excess fluid resuscitation; fortunately, the pt experienced a mild amount of blood loss during the procedure. In the surviving sepsis campaign of 2021, experts recommended adding a second vasopressor i.e. vasopressin when NE is around 0.25-0.5 mcg/kg/min[2]. Vasopressin gtts do not use weight-based dosing and should not be titrated to effect but rather put on a set rate of 0.03 units/min[2]. Corticosteroids and epinephrine can also be considered if NE and vasopressin fail to adequately support BP. Crystalloids are preferred for fluid resuscitation, studies show a possible decrease in mortality with septic pts receiving colloids[3]. Though the pt was acidotic, research currently does not support the administration of bicarbonate to septic pts with a pH >7.15[4]. Due to the likelihood of amputation of the contralateral LE, takebacks for serial gluteal debridement, and the large amount of intraop fluid resuscitation, the decision was made not to extubate; a leak test was not performed. Prior to transport to PACU, the pt was sedated with a fentanyl gtt due to its increased hemodynamic stability profile compared to other sedatives.