Perioperative events - patients undergoing tumor resections may exhibit labile blood pressure, arrhythmias, and tachycardia during and after surgery. Higher risk patients - Risks are higher when a patient has an unrecognized catecholamine-releasing tumor. Patients may have already experienced end-organ damage due to increased catecholamine secretions. The risk of adverse perioperative events are attributed to larger tumor sizes (over 6cm), increased levels of preoperative catecholamine, and longer surgery duration. Preoperative priorities - Recognition of the condition is a high priority. Preoperative symptoms often manifest as hypertension, headache, and sweating. Less common symptoms include orthostatic hypotension, blurred vision, papilledema, loss, polyuria, polydipsia, and constipation. People with hereditary diagnoses such as von Hippel Lindau, multiple endocrine neoplasia type 2, and neurofibromatosis type 1 should be evaluated for pheochromocytoma. When the patient is known to have this condition, assessment should be conducted within 7-14 days before surgery to ensure patient treatment is optimized (control of hypertension and intravascular volume). The endocrinologist will titrate medications (utilizing a combination of alpha-adrenergic blockers, beta-adrenergic blockers, calcium channel blockers, and metyrosine) and treatment to minimize the psychological catecholamine release experienced during removal of the tumor. Preoperative evaluations should include a cardiac evaluation including ECG and echocardiogram, and a type and screen. Anxiolysis with midazolam 1-2 mg is especially recommended (where not contraindicated) to facilitate a smooth induction. Induction - The goal here is to make sure the patient is adequately 'deep' enough to prevent a hypertensive response during intubation and surgical stimulation. Intraoperative management - See 'Intraoperative Drug Management' below. Establish an arterial line and large bore IV access. Those with known depressed cardiac function also need a CVC and PA catheter. General anesthesia is recommended for these patients. Sevoflurane is usually the drug of choice due to its reduced arrhythmogenic potential. Alternatively, TIVA has also been used as a safe technique. Epidural anesthesia may be utilized, but be aware that sympathectomy and vasodilation may exaggerate hypotension after the effluent vein is clamped on the tumor. Intraoperative concerns - See 'Intraoperative Drug Management' below. Excess catecholamines result in volume depletion, postural hypotension, organ and/or limb ischemia, aortic dissection, angina myocardial infarction, acute and chronic cardiomyopathy, congestive heart failure, and arrhythmias. Postop - Most patients remain intubated after the procedure. ICU deposition may be required if the patient requires vasoactive medication. Concerns include recovering normal adrenergic function with stable BP, hypocalcemia, and possible adrenal insufficiency.
Both pheochromocytomas and paragangliomas are neoplasms that secrete catecholamines. Pheochromocytomas are neoplasms of the chromaffin tissue. Paragangliomas are tumors that arise from the extra-adrenal autonomic ganglia. However, paragangliomas are indistinguishable at the histological level and have the same anesthetic management. Twenty-five to 50% of hospital deaths have been attributed to pheochromocytoms undiagnosed or treated before anesthesia induction.
