Pulsus paradoxus
Pulsus paradoxus, or paradoxical pulse, is an exaggerated decline in blood pressure during inspiration. Normally, systolic pressure falls less than 10 mm Hg during inspiration. In pulsus paradoxus, it falls more than 10 mm Hg. (See Comparing arterial pressure waves, page 510.) When systolic pressure falls more than 20 mm Hg, the peripheral pulses may be barely palpable or may disappear during inspiration.
Pulsus paradoxus is thought to result from an exaggerated inspirational increase in negative intrathoracic pressure. Normally, systolic pressure drops during inspiration because of blood pooling in the pulmonary system. This, in turn, reduces left ventricular filling and stroke volume and transmits negative intrathoracic pressure to the aorta. Conditions associated with large intrapleural pressure swings, such as asthma, or those that reduce left-sided heart filling, such as pericardial tamponade, produce pulsus paradoxus.
To accurately detect and measure pulsus paradoxus, use a sphygmomanometer or an intra-arterial monitoring device. Inflate the blood pressure cuff 10 to 20 mm Hg beyond the peak systolic pressure. Then deflate the cuff at a rate of 2 mm Hg/second until you hear the first Korotkoff sound during expiration. Note the systolic pressure. As you continue to slowly deflate the cuff, observe the patient's respiratory pattern. If pulsus paradoxus is present, the Korotkoff sounds will disappear with inspiration and return with expiration. Continue to deflate the cuff until you hear Korotkoff sounds during inspiration and expiration and, again, note the systolic pressure. Subtract this reading from the first one to determine the degree of pulsus paradoxus. A difference of more than 10 mm Hg is abnormal.
You can also detect pulsus paradoxus by palpating the radial pulse over several cycles of slow inspiration and expiration. Marked pulse diminution during inspiration indicates pulsus paradoxus. When you check for pulsus paradoxus, remember that irregular heart rhythms and tachycardia cause variations in pulse amplitude and must be ruled out before true pulsus paradoxus can be identified.
Action stat!
Pulsus paradoxus may signal cardiac tamponade—a life-threatening complication of pericardial effusion that occurs when sufficient blood or fluid accumulates to compress the heart. When you detect pulsus paradoxus, quickly take the patient's vital signs. Check for additional signs and symptoms of cardiac tamponade, such as dyspnea, tachypnea, diaphoresis, jugular vein distention, tachycardia, narrowed pulse pressure, and hypotension. Emergency pericardiocentesis to aspirate blood or fluid from the pericardial sac may be necessary. Evaluate the effectiveness of pericardiocentesis by measuring the degree of pulsus paradoxus; it should decrease after aspiration.
History and physical examination
If the patient doesn't have signs of cardiac tamponade, find out if he has a history of chronic cardiac or pulmonary disease. Ask about the development of associated signs and symptoms, such as a cough or chest pain. Then auscultate for abnormal breath sounds.
Medical causes
Cardiac tamponade.Pulsus paradoxus commonly occurs with cardiac tamponade, but it may be difficult to detect if intrapericardial pressure rises abruptly and profound hypotension occurs. With severe tamponade, assessment also reveals these classic findings: hypotension, diminished or muffled heart sounds, and jugular vein distention. Related findings include chest pain, a pericardial friction rub, narrowed pulse pressure, anxiety, restlessness, clammy skin, and hepatomegaly. Characteristic respiratory signs and symptoms include dyspnea, tachypnea, and cyanosis; the patient typically sits up and leans forward to facilitate breathing.
If cardiac tamponade develops gradually, pulsus paradoxus may be accompanied by weakness, anorexia, and weight loss. The patient may also report chest pain, but he won't have muffled heart sounds or severe hypotension.
Chronic obstructive pulmonary disease (COPD).The wide fluctuations in intrathoracic pressure that characterize COPD produce pulsus paradoxus and possibly tachycardia. Other findings vary, but may include dyspnea, tachypnea, wheezing, a productive or nonproductive cough, accessory muscle use, barrel chest, and clubbing. The patient may show labored, pursed-lip breathing after exertion or even at rest. He typically sits up and leans forward to facilitate breathing. Auscultation reveals decreased breath sounds, rhonchi, and crackles. Weight loss, cyanosis, and edema may occur.
Pericarditis (chronic constrictive).Pulsus paradoxus can occur in up to 50% of patients with pericarditis. Other findings include a pericardial friction rub, chest pain, exertional dyspnea, orthopnea, hepatomegaly, and ascites. Patients also exhibit peripheral edema and Kussmaul's sign—jugular vein distention that becomes more prominent on inspiration.
Pulmonary embolism (massive).Decreased left ventricular filling and stroke volume with massive pulmonary embolism produce pulsus paradoxus as well as syncope and severe apprehension, dyspnea, tachypnea, and pleuritic chest pain. The patient appears cyanotic, with jugular vein distention. He may succumb to circulatory collapse, with hypotension and a weak, rapid pulse. Pulmonary infarction may produce hemoptysis along with decreased breath sounds and a pleural friction rub over the affected area.
Nursing considerations
▪ Prepare the patient for an echocardiogram to visualize cardiac motion and to help determine the causative disorder.
▪ Monitor vital signs and frequently check the degree of paradox because an increase in the degree of paradox may indicate recurring or worsening cardiac tamponade or impending respiratory arrest in severe COPD.
▪ Provide respiratory treatments, such as chest physiotherapy, to avert the need for endotracheal intubation.
Patient teaching
▪ Teach the patient about the underlying disorder and its treatments.
▪ Explain self-care techniques to the patient with COPD, such as pursed-lip, diaphragmatic breathing; coughing and deep-breathing exercises; and proper use of home oxygen equipment.
Book Source Details
- Book Title: Nursing: Interpreting Signs and Symptoms
- Author(s): Springhouse
- Year of Publication: 2007
- Copyright Details: Nursing: Interpreting Signs and Symptoms, Copyright © 2007 Lippincott Williams & Wilkins.
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Copyright Details: Nursing: Interpreting Signs and Symptoms, Copyright © 2008 Williams & Wilkins.
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» Next page: Blood pressure, decreased [Hypotension] (Nursing: Interpreting Signs and Symptoms)
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