Journal: J Cardiothorac Vasc Anesth 22(4):573-575, 2008
Reprint: Princess Alexandra Hospital NHS Trust, Harlow, Essex, United Kingdom (A Philip, MBBS) TT.05 JA0915/015 ©2009
Faculty Disclosure: Abstracted by T. Tilton, who has nothing to disclose.
A case report is made of a 76-yr-old man scheduled for elective abdominal aortobifemoral bypass for a 4-cm infrarenal aneurysm. The patient's pertinent history included hypertension, hypercholesterolemia, impaired glucose tolerance, and claudication. His medications consisted of atenolol, felodipine, bendroflumethiazide, enalapril, and aspirin. Preoperative biochemistry, liver function tests, and coagulation screen were normal; ECG showed a normal sinus rhythm.
Standard noninvasive and invasive monitoring was established; general anesthesia consisted of propofol, fentanyl, atracurium, oxygen, nitrous oxide, and isoflurane. During positioning in the lateral position for placement of an epidural catheter, profound hypotension (40/25 mmHg) occurred without pulse oximetry trace and associated with severe erythema of the face and torso. The initial diagnosis was an anaphylactoid reaction due to exaggerated histamine release from the atracurium. Treatment was 100% oxygen, rapid fluid resuscitation with 2 L of Hartmann’s solution, 2 doses of 0.1 mg epinephrine, 100 mg hydrocortisone, and 10 mg chlorpheneramine. The patient’s condition improved rapidly and surgery was begun; vecuronium replaced atracurium.
Hypotension (68/42 mmHg) recurred after declamping of the second iliac artery, which was treated initially with 1 g 10% calcium chloride. Hypotension worsened (58/38 mmHg) and required 3 doses of metaraminol 0.5 mg to restore normotension. As the abdomen was being closed, a small lesion was noted in the ileum. Handling of the lesion led to marked hypotension (68/45 mmHg) treated with 2 doses of metaraminol 0.5 mg and an epinephrine infusion. The patient's systolic pressure increased to more than 200 mmHg, which was controlled with a nitroglycerin infusion. The differential diagnosis for the resected mass was a suspected carcinoid tumor.
Postoperatively, the patient continued to receive ventilatory and cardiovascular support; octreotide was started to suppress further carcinoid symptoms. Despite aggressive interventions, the patient developed a severe metabolic acidosis that gradually resolved with continuous veno-venous hemodiafiltration. Histology revealed an intramucosal carcinoid tumor infiltrating the entire thickness of the small bowel with foci suggestive of vascular invasion. Serum troponin I was 5.2 mcg/L on day 1 that decreased 2 days later to 2.94, that likely represented reversible, intraoperative myocardial injury. No ECG or echocardiographic abnormalities were found: ejection fraction was 60% with normal systolic function in both ventricles. Recovery progressed over the next 28 days when the patient was transferred from the intensive care unit with no evidence of hepatic or pulmonary metastases.
Only sporadic reports about the hemodynamic effects of undiagnosed carcinoids during noncarcinoid surgery were found. This was the first known reported case presenting intraoperatively during aortic vascular surgery, in which cardiovascular instability is relatively common, hence, the delay in interpreting the clinical signs. It is noted that stimuli such as anxiety, abdominal scrubbing, tumor manipulation, and the use of histamine-releasing drugs can precipitate symptoms. The use of atracurium in this patient may have been the triggering agent. It is recommended that atracurium be avoided in patients with possible carcinoid tumors. Although a rare tumor, it should be part of the differential diagnosis in cases where the cause of marked cardiovascular instability cannot be identified. |
