Patient Safety / Quality

Trends and consequences: Tune into your patient’s patterns

Cynthia Blaise, age 57, has a heart rate of 120 beats/minute (bpm). Should this finding concern you? How would you know? In part, by analyzing her heart-rate trend.
A trend is a general direction—a steady and progressive change in a finding, a minor sign or symptom that recurs or grows more severe, or a sign or symptom linked to other definitive changes (especially systemic ones). A patient’s trend can be more significant than a single isolated finding. It can show if he or she is improving, getting worse, or staying about the same.
Say, for instance, your patient has been receiving antibiotics. Today’s laboratory results show his white blood cell count is 21,000/mm3. As an isolated finding, this might alarm you. But as a reflection of the patient’s trend, this value is reassuring because it was 24,000/mm3 yesterday.
To observe for trends, compare the most recent finding or value with the patient’s normal or baseline value. Ask yourself: Is this a new sign, symptom, or value for this patient? Is it worse, better, or different from what the patient had before? Is it a recurrence of a previous symptom?

Clinical scenario: What did the nurse miss?
Consider this scenario: Nick Lewenstein, a healthy, 5’11”, 235-lb (107-kg) male, age 46, is admitted to the inpatient unit after an uneventful colostomy-reversal surgery. The admitting nurse documents his vital signs: heart rate, 106 bpm; respiratory rate, 20 breaths/minute; blood pressure (BP) 130/83 mm Hg; and temperature, 98.6° F (37° C). She notes that his lungs are clear, he has good pedal pulses, he’s negative for Homans’ sign (calf pain or resistance with dorsiflexion), and his abdominal dressing is clean, dry, and intact.
On the first postoperative day, Mr. Lewenstein refuses to wear prescribed antiembolic stockings and doesn’t receive prophylactic heparin because the nurse needs to clarify his dosage with the physician. At 4 p.m., his vital signs are: heart rate, 125 bpm; respiratory rate, 20 breaths/minute; BP, 107/48 mm Hg; and temperature, 99.7° F (37.6° C). At 10:15 p.m., the nurse notifies the attending physician of the patient’s reported pain level of 10 on a 0-to-10 scale, as well as his latest vital signs: heart rate, 130 bpm; respiratory rate, 24 breaths/minute; BP, 104/46 mm Hg; and temperature, 99.7° F (37.6° C). The physician orders morphine to relieve breakthrough pain.

Mr. Lewenstein clearly has new-onset tachycardia. Pain and anxiety are benign causes of a rapid heart rate; giving morphine can help determine if these symptoms explain his fast pulse. However, the nurse should keep in mind that the first signs of shock are increased heart and respiratory rates.

Scenario continued
Throughout the night, the patient’s heart rate hovers between 130 and 140 bpm, but his BP drops to 90/60 mm Hg. The nurse notes he was sleeping at 2 a.m., 4 a.m., and 6 a.m.
At 8 a.m. on the second postoperative day, his vital signs are: heart rate, 140 bpm; respiratory rate, 20 breaths/minute; BP, 88/60 mm Hg; and temperature, 99.9° F (37.7° C). They’re similar at noon. The nurse documents the patient’s pain level at 5 and notes a negative Homans’ sign.

Discussion continued
Mr. Lewenstein’s trend of abnormally sustained tachycardia requires in-depth evaluation and renotification of the physician—and the nurse failed to perform both. She also failed to monitor his pulse oximetry values and breath sounds. The prolonged abnormality in his vital signs should have led her to suspect he was suffering from more than just anxiety or discomfort.

At 3:30 p.m., Mr. Lewenstein stands up to ambulate in the hall, then collapses and suffers cardiac arrest. The code team is unable to revive him. An autopsy shows he had a pulmonary embolism.

Lessons learned
About 90% of pulmonary emboli originate from deep vein thrombosis (DVT). Mr. Lewenstein had venous stasis, hypercoagulability, and major vessel-wall injury—major risk factors for DVT. These conditions resulted from surgery-related dehydration, immobility, and major abdominal vessel manipulation (which causes vessel-wall inflammation). The delay in heparin administration and his refusal to wear antiembolic stockings contributed to DVT development.
DVT has no typical presentation. Classic signs and symptoms of a pulmonary embolism (sudden severe shortness of breath, anxiety, hemoptysis, and cyanosis) occur in less than 20% of cases. But unexplained cardiorespiratory problems should raise suspicion because nonspecific tachypnea and tachycardia are among the most common signs of an embolism.
With Mr. Lewenstein, the main problem wasn’t that the nurse failed to suspect embolism or DVT. It was that she failed to perform follow-up trend analysis or notify the physician of the sustained abnormal trend of tachycardia and decreasing BP. Also, she should have monitored the patient’s pulse oximetry and breath sounds to help detect subtle abnormalities.
Unfortunately, DVT can be hard to diagnose; roughly 31% to 69% of patients with DVT have normal findings. One of the most reliable findings is unilateral edema of the affected leg (one calf that’s at least 3 cm larger than the other one, measured 10 cm below the tibial tuberosity). Another finding, a positive Homans’ sign, occurs only in 10% of DVT cases and isn’t diagnostically reliable.
Venography is the gold standard for diagnosing DVT but is rarely done. Consequently, DVT diagnosis usually hinges on probability scoring (such as the Wells criteria), the D-dimer blood test (commonly elevated in thromboembolic disease), ultrasonography, or a combination. A clinical decision rule (a process for diagnosis) improves diagnostic accuracy and efficiency. One study found that using the D-dimer test plus a clinical rule effectively ruled out DVT without ultrasonography in patients at low or medium risk. Another study found a single negative ultrasound sufficiently ruled out DVT (with the D-dimer test or a clinical rule).
As a nurse, one of your goals is to recognize when a patient might be in trouble and thus allow a “rescue” before cardiac arrest, as the in-hospital survival rate from cardiac arrest to discharge is only about 15%. A rapid response team (RRT) can aid assessment and stabilization of a patient experiencing an acute significant change. For adults, the Institute for Healthcare Improvement recommends activating the RRT for a sustained heart rate faster than 125 bpm. Some facilities customize this recommendation to any acute heart-rate change exceeding 10 minutes. Using such a mandatory reporting process could have helped the nurse find the cause of Mr. Lewenstein’s unexplained sustained tachycardia. His trend was apparent, but the nurse didn’t take it seriously or investigate it to allow a rescue.

Check a trend, save a life
Saving a patient doesn’t always mean performing a heroic exceptional action. In some cases, you can save a patient just by performing the nursing process—including analyzing the patient’s trends—thoroughly and consistently. Checking trends, comparing them to the patient’s usual findings, and listening to his or her complaints can point the way to additional nursing or medical care that may be needed.

Selected references
Clark SP, Aiken LH. Failure to rescue. Am J Nurs. 2003;203:42-47.
Koschel MJ. Pulmonary embolism: quick diagnosis can save a patient’s life. Am J Nurs. 2004;104(6):46-50.
Scholle CC, Mininni NC. How a rapid response team saves lives. Nursing2006. 2006;36(1):36-40.
Zimmermann PG. Guiding principles at triage: advice for new triage nurses. J Emerg Nurs. 2002;28(1):24-33.
Zimmermann PG, Herr RD, eds. Triage Nursing Secrets. St. Louis, MO: Mosby; 2006.

Polly Gerber Zimmermann is an Assistant Professor of Nursing at Harry S. Truman College in Chicago, Illinois.

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