Pulmonary hypertension

Question 1

Although there is no widely accepted range for normal pulmonary blood pressures, pulmonary hypertension (PH) exists when the pulmonary systolic pressure exceeds ___mm Hg in the
presence of normal cardiac output (CO) and pulmonary capillary wedge pressure.

Answer 1

25

Question 2

During exercise pulmonary hypertension is considered a pulmonary artery pressure (PAP) greater than __ mm Hg.

Answer 2

30

Question 3

Trivia:

What appetite stimulant can produce pulmonary hypertension?

Answer 3

Flufenamine

Question 4

How much ejection fraction to consider RV failure?

Answer 4

<45%

Question 5

Standard therapies for PH

Answer 5

1) Supplemental O2 (target O2 sat >90%)
2) Diuretics (congestion)
3) Anticoagulants (INR: 1.5 to 2.0)
4) Cardiac glycosides (RV failure)

Question 6

What calcium channel blocker should not be given with PH due to its negative inotropic effects?

Answer 6

Verapamil

Question 7

What intraoperative measures may decrease PH?

Answer 7

1) Avoid hypoxemia (PEEP < 15 cmH2O)
2) Nitroglycerin, dobutamine or dopamine to improve CO
3) Avoid CVP <10
4) Correct acidosis (thermoregulate, PaCO2 of 30 mmHg)
5) Inotropes (milrinone & amrinone)
6) Norepinphrine (careful titration)
7) Vasodilators

Question 8

Volatile anesthetic of choice for PH?

Answer 8

Isoflurane (1-1.2 MAC)
Volatile anesthetic should be titrated carefully since impaired RV function is a risk
Nitrous oxide can increase PVR and attenuate HPV; its use in PH is best avoided.

Question 9

Dosage of nitroglycerin in PH?

Answer 9

1-3 mcg/kg/min

Above 3 mcg/kg/min, venodilation may become excessive, decreasing preload and requiring intravenous fluid augmentation.

Question 10

Dosage of nitroprusside in PH?

Answer 10

0.5 to 1 mcg/kg/min

Long-term use is associated with tachyphylaxis and the potential for cyanide toxicity.

Question 11

Are found in vascular endothelium and act via specific prostaglandin receptors
to stimulate adenylate cyclase and increase cyclic adenosine monophosphate.

Answer 11

Prostanoids

The production of the naturally occurring PGI2 is decreased in PH.

Question 12

What is the value of adenosine?

Answer 12

Adenosine relaxes smooth muscle cells in the pulmonary circulation. It has a half-life of only 9 seconds; thus, when administered intravenously, its actions are relatively confined to the pulmonary circulation.