Patient selection: pheochromocytoma, prior to surgery
Outcomes: times with systolic blood pressure during surgery > 160 mm Hg OR mean arterial pressure (MAP) below 60 mm Hg
Risk factors for hemodynamic instability during surgery:
(1) greater diameter of the pheochromocytoma (> 4 cm)
(2) high plasma concentrations of norepinephrine
(3) postural fall in mean arterial blood pressure after alpha blockade >= 10 mm Hg
(4) mean arterial blood pressure > 100 mm Hg after alpha blockade
where:
• 29% of pheochromocytomas did not produce norepinephrine.
• The median value for norepinephrine was 1,648 pg/mL with range 36 to 250,000.
• The cut-off for norepinephrine was not given, It would also be affected by methodology. A multiple of the upper limit of normal reference range is worth investigating.
• The postural fall in blood pressure is supine mean arterial blood pressure minus upright mean arterial blood pressure).
• On pages 681-682 the postural fall is >= 10 mm Hg but in conclusion it is > 10 mm Hg.
• A mean arterial pressure of 100 mm Hg corresponded to a blood pressure of 130 mm Hg systolic and 85 mm Hg diastolic.
A high mean arterial blood pressure at presentation was also associated with hemodynamic instability during surgery (conclusion, page 685)
