Blood Pressure

Question 1

What is the range of normal pressures in each chamber of the heart?

Answer 1

Right atrium, 1–8 mmHg; right ventricle, 15–30/0–8 mmHg; left atrium, 2–12 mmHg; left ventricle, 100–140/0–12 mmHg.

Nagelhout 6e. p493

Question 2

What is the normal value for mean pulmonary artery pressure?

Answer 2

Mean pulmonary artery pressure normally is about 16 mmHg. Systolic/diastolic pressures average 25/8 mm Hg.

Guyton, TMP, 14e. p504

Question 3

What is the normal range of values for pulmonary artery occlusion pressure (PAOP), also called pulmonary capillary wedge pressure (PCWP)?

Answer 3

Normal PAOP = 6–12 mmHg. When stated as wedge pressure, PCWP = 2–12 mmHg.

Stoelting, Co-exist 8e. p 400

Question 4

What is the normal value for mean systemic arterial pressure?

Answer 4

Normal mean arterial pressure ranges from 80–120 mmHg.

Nagelhout, NA, 7e. p451

Question 5

How do you estimate mean arterial pressure (MAP)?

Answer 5

Use the 1, 2, 3 rule. MAP = (1 x SBP + 2 x DBP)/3. Alternatively, MAP can be calculated as follows: MAP = DBP + (1/3) (pulse pressure) = DBP + (1/3) (SBP–DBP).

Morgan, et al., Clin. Anes. 6e. p364

Question 6

What causes a change in blood pressure when changing the patient’s position?

Answer 6

Altered preload (altered venous return) is most responsible for a change in blood pressure when the patient is re-positioned.

Barash, Clin. Anes. 8e. p288

Question 7

What are the two determinants of arterial blood pressure? What law applies?

Answer 7

The two determinants of systemic arterial blood pressure are systemic vascular resistance (SVR) and cardiac output (CO). This is an application of Ohm’s law.

Morgan, et al., Clin. Anes., 6e. p 364

Question 8

What most determines systemic vascular resistance?

Answer 8

Systemic vascular resistance (SVR) is determined by the tone (degree of constriction) of arterioles and small arteries.

Morgan, et al., Clin. Anes. 6e. p 364

Question 9

What is the normal range of values for systemic vascular resistance (SVR)?

Answer 9

The normal range for SVR is 800–1500 dynes∙sec∙cm–5.

Nagelhout, NA, 7e. p452

Question 10

How do you calculate systemic vascular resistance (SVR)?

Answer 10

SVR = [(MAP–CVP)/CO] x 80, where MAP is mean arterial pressure, CVP is central venous pressure, and CO is cardiac output. The units for SVR are dynes-sec-cm–5.

Nagelhout, NA, 7e. p452

Question 11

If mean arterial pressure is 80 mmHg, cardiac output 9 liters/min, and central venous pressure 8 mmHg, calculate SVR.

Answer 11

SVR = [(MAP–CVP)/CO] x 80 = [(80–8)/9]