Causes
Conditions
Renal
Parenchymal (chronic glomerulo-/pyelonephritis)
Renal vascular (e.g., renal artery stenosis, aneurysm) and general diseases with renal involvement (e.g., diabetes mellitus, gout, lupus)
Endocrine
Conn syndrome
Cushing syndrome
Pheochromocytoma
Hyperthyroidism
Acromegaly
Cardiovascular
Aortic stenosis
Neurogenic
Increased intracranial pressure
Encephalitis/meningitis
Tumors
Porphyria
Pregnancy associated
Pregnancy-induced hypertension
Preeclampsia, eclampsia
Medications
Corticosteroids
Oral contraceptives
Nonsteroidal anti-inflammatory drugs
MAO inhibitor
Cyclosporin A
Blood diseases
Polycythemia vera
3.2.4 How Are Patients Prepared for Elective Pheochromocytoma Surgery?
Massive catecholamine release due to surgical tumor manipulation can lead to a life- threatening hypertensive crisis and cardiac arrhythmias. Therefore, patients are premedicated with α-blockers and sometimes also with β-blockers [11]. Phenoxybenzamine, a nonselective α-antagonist, treats the catecholamine-induced vasoconstriction, normalizes blood pressure, and improves cardiac output.
Preparation is begun 14 days before the scheduled operation with 10–20 mg phenoxybenzamine PO and increased by 10–20 mg/day until the blood pressure is stabilized. The target pressure is 160/90 mmHg. The patients often complain of orthostatic vertigo. This is a result of hypovolemia, which must be compensated for by drinking fluids until the hemoglobin drops. Sometimes undesired tachycardia occurs as a side effect of phenoxybenzamine, in which case a shorter working selective α1-antagonist such as doxazosin is used, or a β-blocker is added.
Importantly with pheochromocytomas, β-blockade should not be started before the α-blockade has taken effect. Otherwise, removal of the β2 vasodilator effects can lead to severe hypertension with left heart failure. When urgent surgery is required, phenoxybenzamine can be given IV in the ICU under careful monitoring. The sensation of a stuffed nose is a good indication for a functioning α-blockade.
Patients need good anxiolytics and should receive benzodiazepines the night before and the morning of the operation, considering the general contraindications, of course.
Note:
Since the operation is usually scheduled electively, unblocked patients should not be in the OR!
3.2.5 Which Medical Errors Do You See in the Presented Case?
3.2.5.1 Epidural Utilization
In Sect. 3.1.3 it is already described that utilization of an epidural after a bloody insertion has to be viewed critically. Whether such utilization is actually malpractice is unclear. Nevertheless, utilization of the epidural with a local anesthetic immediately before removal of a neuroendocrine tumor is medically questionable.
3.2.5.2 CVP Measurement
Continuous CVP measurements were not performed.
3.2.5.3 Blood Pressure Monitoring on the Ward/Preoperative Diagnostics
While checking the chart on the ward, Dr. Constantine couldn’t find a blood pressure measurement for Mr. Anderson. Furthermore, one may assume that the high-quality radiographic images should have localized the tumor at the adrenal gland. However, further investigation into the localization of the tumor was not carried out. The initial diagnosis of an ileus was never questioned.
3.2.5.4 Monitoring of Laboratory Results
There was no intraoperative measurement of lab values. When the PVCs occurred, hematocrit and electrolytes should have been checked.
3.2.6 Which Systems Failures Can Be Found in the Presented Case?
3.2.6.1 Informed Consent from the Patient
Informed consent requires a discussion between the physician and the patient concerning the risks, benefits, and alternatives to treatments. It is an ethical obligation of the practice of medicine and a legal requirement in the U.S. in all 50 states [7]. The patient must have “competence” and “capacity” to provide informed consent. Competence refers to the patient’s legal authority to make decisions. Adult patients, generally patients who are 18 or older, are presumed legally competent unless otherwise determined by a court. Capacity refers to a determination made by medical professionals that a patient has the ability to make a specific decision at a specific time. The informed consent discussion should focus on the indications for the proposed treatment, description of the procedure in terms a layperson can understand, and an explanation of viable alternatives. Disclosure of material risks of the recommended and alternate treatments is required. Material risks are risks that occurred frequently (e.g., backache, spinal headache, or failure after an epidural) as well as those that are rare but may result in serious morbidity or mortality (e.g., nerve injury/paralysis, seizures, coma, death). Some states also require disclosure of all persons anticipated to be involved in the patient’s anesthetic care. Some hospitals and some states require a separate written anesthesia consent form. In other places, a written surgical consent form suffices, with a verbal informed consent discussion about anesthesia risks. Specific risks described in the discussion, such as persistent numbness or paralysis from the epidural, should be charted on the preoperative evaluation or anesthetic record.