Non-invasive measurements of cardiac output (CO), systemic vascular resistance (SVR), corrected aortic flow time (FTc) and stroke volume (SV) are useful parameters during laparoscopic resection of pheochromocytoma (adrenalectomy) to document the intraoperative changes in volume status and to estimate the volume depletion.

Pheochromocytomas and extraadrenal paragangliomas are catecholamin-producing tumours deriving from the adrenal medulla and sympathetic ganglia. The only causal therapy is surgical resection. Nowadays, laparoscopic adrenalectomy is thought to be the optimal approach. Chronic volume depletion due to chronic hypertension and preoperative α-adrenoreceptor-blockade (to avoid the effects of intraoperative catecholamine-excess) often lead to hypotension after resection of the tumour. Volume reload with high amounts of fluid is often needed. Therefor some authors recommended invasive measurement (pulmonary artery catheter) to control cardiac output parameters and fluid balance. However, there are non-invasive methods to measure cardiac output(CO), systemic vascular resistance(SVR), stroke volume(SV) and corrected aortic flow time(FTc) to estimate volume status. Except transesophageal echocardiography, other techniques such as transoesophageal doppler and pulse pressure methods exist but have not been investigated during surgical therapy for pheochromocytoma so far. The esophageal Doppler currently represents the "gold standard" for perioperative fluid replacement therapy.

The study's hypothesis is that non-invasive measurements of cardiac output (CO), systemic vascular resistance (SVR), corrected aortic flow time (FTc) and stroke volume (SV) are useful parameters during laparoscopic resection of pheochromocytoma (adrenalectomy) to document the intraoperative changes in volume status and to estimate the volume depletion.

Inclusion Criteria:

• Planned laparoscopic adrenalectomy for pheochromocytoma (Biochemical confirmed adrenal and extraadrenal pheochromocytoma)
• Planned laparoscopic adrenalectomy for hormonally inactive adrenal tumor

Exclusion Criteria:

• Risk of esophageal bleeding or perforation exists (i.e., liver disease with portal hypertension and/or esophageal varicoses, other esophageal anomalies).

Patients suffering from pheochromocytoma will be recruited by the Department of Surgery, Medical University of Vienna