Page 129 - Critical Care Nursing Demystified

114 CRITICAL CARE NURSING DeMYSTIFIED

TABLE 3–6 Preload Enhancers and Reducers (Continued)
Action Use Precautions
Nitroglycerin Causes both Use for anginal 1. Sublingually (SL),
(Tridil; Nitro- arterial and episodes and intravenously (IV), and
Dur) venous dilata- prevention of intranasally (IN);
tion angina always take the BP
Selectively Also used to before administering
dilates the cor- bring the BP and 5 minutes after
onary arteries, down acute for a total of three SL
increasing blood coronary syn- or IN. Hold if the BP is
flow to the drome (ACS) < 110 systolic
myocardium 2. May cause hypoten-
sion and headaches,
Decreases pre- which are dose related
load
Sodium nitro- Profoundly and Fast acting; 1. Thiocyanate and
prusside rapidly dilates only used in cyanide toxicity can
(Nipride) the peripheral HTN emergen- occur. Assess for
arteries by cies nausea, confusion,
relaxing smooth and tinnitus
muscles result- 2. Careful and continu-
ing in a drop ous BP monitoring;
in BP arterial line might be Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
indicated to closely
monitor BP
Morphine Dilates the The analgesic 1. Watch respirations as
sulfate venous system of choice for can cause depression
angina and ACS leading to hypoxemia
2. Observe BP closely as
can cause hypotension
3. Watch for overseda-
tion, especially in
elderly
4. Reversal agent is
naloxone (Narcan)

The heart has to work harder to maintain this pressure. If the vessels are very
small, then the pressure in the vessels is very high, which would cause more
pressure in the CV system. Medications that decrease the diameter of the
arteries or veins in the CV system are known as vasopressors or preload
enhancers. Vasopressors are administered when the BP is too low as in a
shocklike state. Commonly administered vasopressors in critical care include
dopamine and Levophed.