Assess the cause – Hypertension is a very common condition in the OR. Sometimes it is due to ‘white coat’ anxiety, otherwise understood as the natural anxiety that comes with doctors visits and surgery. It is always helpful to ask if the patient stopped taking blood pressure medication, levels of anxiety, and what baseline pressures are.

Labile – patients with chronic high blood pressure tend to be very labile/sensitive to the drugs given during surgery. Its always good practice to have vasopressors out and to anticipate surgical events (like incision/surgical stimulation).

Both arms – Sometimes there’s a difference in blood pressure when compared between right and left arms. A 10-20 point difference is common. Most often, the higher pressure is in the right arm. A consistent difference warrants taking the blood pressure from the arm consistently showing elevated pressures. Large and persistent differences warrant further investigation for possible coarctation, dissection, or aneurysm of the thoracic aorta; Other possibilities include Takayasu (pulseless) disease, and intra/extra arterial obstructions such as peripheral vascular disease. Peripheral vascular disease is further confirmed by a considerably diminished radial pulse in the arm with the diminished pressure.

Primary hypertension is hypertension that DOES NOT have an identifiable underlying cause. This form of hypertension accounts for 95% of hypertension cases.

Secondary hypertension is hypertension the DOES have an identifiable underlying cause. This form of hypertension accounts for 5% of hypertension cases. Renal Artery Stenosis is the most common cause of this form of hypertension.

Increased systemic vascular resistance (SVR) is the cause for the vast majority of hypertension cases. A small percentage is due to increased cardiac output (CO).

Most cases are have an unidentifiable cause. The primary culprits are thought to be a malfunction of the systems which regulate SVR. These consist of:
1. Sympathetic Nervous System (SNS)
2. The Renin-Angiotensin-Aldosterone System (RAAS)
3. Vasopressin