Currently, the number one cause of death in the US is heart disease, with 610,000 deaths reported annually.1,2 Given the magnitude of the opioid epidemic, critical care nurses will care for more patients who have or will develop cardiovascular disease while taking prescribed or illicit opioids. Critical care nurses need to understand how these drugs affect the cardiovascular system to deliver the best possible care and appropriate patient education. This article reviews research literature focused on the effects of opioids (both prescription and illicit) and their impact on the cardiovascular system. It also discusses recommended interventions for critical care nurses who assess, care for, and educate patients taking opioids long term. For the purpose of this discussion, long term is defined as at least 3 months for opioid medications and at least 4 weeks for opioid agonist medications.
Reviewing the literature
The authors conducted a systematic review of the literature using Medline, Ovid, and CINAHL. An exhaustive search was performed including the keywords “opioid,” “opiate,” “cardiovascular,” “heart,” and “cardiac.” The search was limited to peer-reviewed articles published from 2013 through 2017 with human subjects.
The authors identified seven studies relevant to this review. Each of the studies noted an effect of opioids on the cardiovascular system when used long term. Although research questions and methodology differed, each group of researchers found effects directly harmful to the heart.
According to Seltenhammer and colleagues, long-term opioid exposure may lead to structural cardiac changes.3 These researchers studied myocardial tissue samples from 76 heroin- and morphine-related deaths and 23 nondrug-related deaths. They found a significant correlation between long-term abuse of opioids and myocardial fibrosis.
Long-term opioid use can also cause detrimental effects on the cardiac conduction system, specifically a prolonged QT interval. Mason and colleagues found a 7.2 millisecond increase in QT corrected for heart rate using the Fridericia formula (QTcF) in patients being treated for chronic pain with opioids, specifically hydrocodone, oxycodone, and morphine.4 The QTcF is used to compare QT intervals across a range of heart rates. A prolonged QT interval is associated with a slower heart rate and places patients at a greater risk for torsades de pointes.5
Isbister and colleagues studied 19 patients consuming methadone and 20 patients prescribed buprenorphine for opioid agonist treatment who were monitored for 24 hours using ambulatory electrocardiography.6 Seven patients on methadone maintenance developed a prolonged QT interval that was considered significant (P value, .008). The other patients on methadone were found to have longer QT intervals compared with patients in the control group, although their values were still considered in the normal range. Patients prescribed methadone in this study had no known risk factors that would contribute to a prolonged QT interval, such as medication use and personal or family history of cardiac disease. No association between methadone dose and QT interval prolongation was found.
In a study of 58 patients, Keller and colleagues found that meperidine can also prolong the QT interval, independent of heart rate, in correlation with the plasma drug level.7 Similarly, three other studies showed that various opioids can prolong the QT interval.4,6,7
The long-term use of opioids may lead to an increased risk of cardiovascular disease and death. Khodneva and colleagues studied prescription opioid use for noncancer chronic pain in a population of 29,025 participants.8 They found a significant risk of cardiovascular death and coronary heart disease in those who use prescription opioids.
In another study regarding the use of opioid prescriptions for chronic noncancer pain, LoCasale and colleagues studied 36,839 patients and found an increased risk of unstable angina, myocardial infarction, heart failure, transient ischemic attack, and stroke in patients with preestablished cardiovascular disease who took opioids for more than 6 months.9
Ray and colleagues found that patients taking a long-acting opioid for chronic noncancer pain had a greater risk of death compared with those taking other analgesics, antiepileptic drugs, or cyclic antidepressants.10 Of 53 patients who died from a nonoverdose-related cause, 36 died from cardiac-related disorders. This study demonstrated a significant relationship between cardiac-related deaths and long-acting opioids (P value, .02). All three studies regarding the use of opioids for chronic noncancer pain found a detrimental effect on the cardiovascular system.8-10
Gaps in the literature
The literature has demonstrated a possible relationship between the use of prescribed opioids for chronic pain and adverse cardiovascular reactions. Additional research should be conducted on those who use illicit opioids as well as those recovering from opioid addiction to investigate the effects of opioids on the cardiovascular system in these patients. In addition, no evidence-based screening tool or educational guideline is available to help critical care nurses assess and counsel patients who are at risk for cardiovascular complications due to long-term opioid use.
Implications for critical care nursing practice
The evidence reviewed by the authors demonstrated the effects of long-term opioid use on the cardiovascular system. The implication for nursing practice is the need for critical care nurses to screen, assess, and educate patients who take opioids. In collaboration with healthcare providers, critical care nurses can assess heart structure and function with results of studies such as electrocardiography and continuous ambulatory ECG monitoring to screen for dysrhythmias and disorders of myocardial repolarization, such as prolonged QT intervals.
In addition, critical care nurses should continue to assess use, misuse, and abuse of opioids among all patients. Appropriate counseling and referrals for addiction treatment should be offered to patients for continuity of care. Equally important, critical care nurses must educate patients about cardiovascular risks associated with long-term opioid use. Critical care nurses should continue to reinforce education on diet, exercise, smoking cessation, stress management, and annual physical exams to promote cardiovascular health.
Responding to the epidemic
The reviewed literature demonstrated that many opioids have adverse reactions on the cardiovascular system that may lead to structural, electrical, and functional complications. In view of the opioid epidemic and the high rate of cardiovascular disease and death in the US, critical care nurses must understand how opioids affect the cardiovascular system during long-term use. By remaining current with the evidence, critical care nurses can more effectively care for patients using opioids chronically and lower their risk of cardiovascular disease and death.
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