Pulse pressure, narrowed
Pulse pressure, narrowed: Excerpt from Handbook of Signs & Symptoms (Third Edition)
Pulse pressure, the difference between systolic and diastolic blood pressures, is measured by sphygmomanometry or intra-arterial monitoring. Normally, systolic pressure exceeds diastolic by about 40 mm Hg. Narrowed pressure — a difference of less than 30 mm Hg — occurs when peripheral vascular resistance increases, cardiac output declines, or intravascular volume markedly decreases.
With conditions that cause mechanical obstruction, such as aortic stenosis, pulse pressure is directly related to the severity of the underlying condition. Usually a late sign, narrowed pulse pressure alone doesn’t signal an emergency, even though it commonly occurs with shock and other life-threatening disorders.
History and physical examination
After you detect a narrowed pulse pressure, check for other signs of heart failure, such as hypotension, tachycardia, dyspnea, jugular vein distention, pulmonary crackles, and decreased urine output. Also check for changes in skin temperature or color, the strength of peripheral pulses, and the patient’s level of consciousness (LOC). Auscultate the heart for murmurs. Ask about a history of chest pain, dizziness, or syncope.
Medical causes
Cardiac tamponade
With cardiac tamponade, a life-threatening disorder, pulse pressure narrows by 10 to 20 mm Hg. Paradoxical pulse, jugular vein distention, hypotension, and muffled heart sounds are classic. The patient may be anxious, restless, and cyanotic, with clammy skin and chest pain. He may exhibit dyspnea, tachypnea, a decreased LOC, and a weak, rapid pulse. A pericardial friction rub and hepatomegaly may also occur.
Heart failure
Narrowed pulse pressure occurs relatively late and may accompany tachypnea, palpitations, dependent edema, steady weight gain despite nausea and anorexia, chest tightness, slowed mental response, hypotension, diaphoresis, pallor, and oliguria. Assessment reveals a ventricular gallop, inspiratory crackles and, possibly, a tender, palpable liver. Later, dullness develops over the lung bases, and hemoptysis, cyanosis, marked hepatomegaly, and marked pitting edema may occur.
Shock
With anaphylactic shock, narrowed pulse pressure occurs late, preceded by a rapid, weak pulse that soon becomes uniformly absent. Within seconds or minutes after exposure to an allergen, the patient experiences hypotension, anxiety, restlessness, and feelings of doom, along with intense itching, a pounding headache and, possibly, urticaria. Other findings include dyspnea, stridor, and hoarseness; chest or throat tightness; skin flushing; nausea, abdominal cramps, and urinary incontinence; and seizures.
With cardiogenic shock, narrowed pulse pressure occurs relatively late. Typically, peripheral pulses are absent and central pulses are weak. A drop in systolic pressure to 30 mm Hg below baseline, or a sustained reading below 80 mm Hg not attributable to medication, produces poor tissue perfusion. Poor perfusion produces tachycardia; tachypnea; cold, pale, clammy skin; cyanosis; oliguria; restlessness; confusion; and obtundation.
With hypovolemic shock, narrowed pulse pressure occurs as a late sign. All peripheral pulses become first weak and then uniformly absent. Deepening shock leads to hypotension, urine output of less than 25 ml/hour, confusion, a decreased LOC and, possibly, hypothermia.
With septic shock, narrowed pulse pressure is a relatively late sign. All peripheral pulses become first weak and then uniformly absent. As shock progresses, the patient exhibits oliguria, thirst, anxiety, restlessness, confusion, and hypotension. Extremities become cool and cyanotic; the skin becomes cold and clammy. In time, he develops severe hypotension, persistent oliguria or anuria, respiratory failure, and coma.
Special considerations
Monitor the patient closely for changes in the pulse rate or quality and for hypotension or a diminished LOC. Prepare him for diagnostic studies, such as echocardiography, to detect valvular heart disease or cardiac tamponade secondary to a pericardial effusion.
Pediatric pointers
In children, narrowed pulse pressure can result from congenital aortic stenosis as well as from disorders that affect adults.
Book Source Details
- Book Title: Handbook of Signs & Symptoms (Third Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Handbook of Signs & Symptoms (Third Edition), Copyright © 2006 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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