P038: MASKED BY THE DRAPES: DIAGNOSIS AND MANAGEMENT OF REFRACTORY HYPOTENSION
Merlin Perez Navarro, MD; Cecilia K Nosti, MD; Lisa Freedman, CAA; Antonio Navarro, MD; Giselle Helo, MD
Memorial Healthcare System
Background: The diagnosis and management of refractory, intraoperative hypotension under general anesthesia is often complex. While clinicians routinely know the patient’s medical history and perioperative course, patients cannot describe their symptoms, and important physical signs may be hidden by surgical draping and positioning. As a result, clinicians rely on vital signs, end-tidal CO2 values, ventilatory parameters, and the patient's response to specific treatment for a diagnosis. Here we describe management of refractory post-induction hypotension in a patient who received a brachial plexus nerve catheter followed by general anesthesia.
Case Presentation: An 18-year-old ASA 1 73.5kg male presented for right shoulder arthroscopy with Bankart repair. A preoperative interscalene continuous nerve catheter was placed (15 mL of 0.5% ropivacaine), followed by induction of anesthesia and endotracheal intubation. Medications included propofol, fentanyl, lidocaine, and rocuronium. The patient was positioned in left lateral decubitus with limited access to the patient’s airway. He initially developed hypotension (MAP 55 mm Hg) and tachycardia that was treated with phenylephrine. Cefazolin (2g) was given for surgical site infection prophylaxis. MAP decreased further (30 mm Hg) but was unresponsive to phenylephrine, fluids, or vasopressin. End-tidal CO2 remained above 30 mm Hg throughout.
A transthoracic echocardiogram revealed no gross abnormalities. Lipid emulsion was administered for a suspected delayed presentation of LAST while an arterial line was placed and a continuous epinephrine infusion was started for treatment of hypersensitivity. Intravenous benadryl 50mg and methylprednisolone 125mg were also administered. Upon removal of the drapes, facial swelling was noted, supporting a diagnosis of hypersensitivity. The patient was transferred intubated to the intensive care unit. A tryptase level of 28.3 ug/L (normal: 2.2-13.2) further supported a drug hypersensitivty reaction. The patient was extubated later that evening and discharged the following day without any complications.
Discussion: Delayed local anesthetic systemic toxicity (LAST) and perioperative hypersensitivity were both considered as potential diagnoses in this case. The use of high dose epinephrine for treatment of hypersensitivity is discouraged in management of LAST, complicating management.
Both hypersensitivity and LAST can present with refractory hypotension, but for different reasons (Table 1). In our case, heart function appeared intact on TTE but there was a surprisingly mild decrease in EtCO2 considering the degree of hypotension (6). While delayed LAST is relatively rare, the risk is greater with interscalene brachial plexus blocks and catheter placement (1-4), leading us to administer lipid therapy while we began treatment for a possible hypersensitivity reaction. When the drapes were removed, cutaneous changes supported the latter diagnosis, which was confirmed by tryptase levels. Allergy testing for the causative agent is pending.
References:
1. doi:10.1097/AAP.0000000000000720
2. doi:10.1111/aas.12521
3. doi:10.1016/j.ajem.2022.06.017
4. doi:10.2147/LRA.S154512
5. doi:10.1016/j.jaip.2020.05.010
6. doi:10.1093/bja/aex310
