Introduction: Regimens for pre-operative α and β-blockade for patients with secretory phaeochromocytomas/paragangliomas vary widely between centres. The worldwide lack of availability of intravenous phenoxybenzamine (Goldshield) has removed a useful tool in the management of phaeochromocytoma crisis and has necessitated a change in our institutions routine pre-operative strategy. We compare pre, peri and post-operative surrogate measures of blockade in a cohort of patients receiving iv phenoxybenzamine with an oral regimen.
Methods: Of 41 patients with phaeochromocytoma/paraganglioma seen between 2009 and 2012, 19 patients were included in this retrospective audit. Patients were only included if the same surgeon (RAC) and anaesthetist (MA) were present and were excluded if a transfusion was required. All patients had α blockade with oral phenoxybenzamine for at least 3 weeks prior to surgery. In the immediate 3-day pre-operative period five patients had accelerated oral phenoxybenzamine therapy ± intravenous fluids and 14 patients had intravenous phenoxybenzamine ± intravenous fluid. We assessed intraoperative parameters of α blockade efficacy including requirement for sodium nitroprusside (SNP) and intravenous fluids. We assessed postoperative fluid requirement, use of and response to adrenaline, blood pressure and heart rate variability.
Results: Patients treated with intravenous phenoxybenzamine pre-operatively required less SNP (6.4 vs 12.3 mg) and less intra-operative intravenous fluids (2.9 l vs 5.2 l) compared to patients treated with oral phenoxybenzamine. Mean systolic BP in the 3-day pre-operative period was lower in the i.v. group (123 vs 130 mmHg) and the immediate post-operative systolic BP was higher in the iv group (108 mmHg vs 93 mmHg). Data including tumour type and size, catecholamine/metanephrine levels, postural BPs, and dose of α and β-blockade will be presented.
Conclusion: Although a small cohort, the data suggest that patients treated with iv phenoxybenzamine have better pre-operative BP control, require less intraoperative intervention and have less post-operative hypotension than patients treated with oral phenoxybenzamine. We invite other centres to report their experience.