Susan J. McCall, MSN, RN
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: September 4, 2012
For the oncology nurse, it is common to care for a patient who has a complaint of shortness of breath. This symptom, also known as dyspnea, is often significantly distressing and is a frequent complication of primary or metastatic neoplastic disease. According to the American Thoracic Society (1999), dyspnea is defined as “a subjective experience of breathing discomfort that is comprised of qualitatively distinct sensations that vary in intensity.” The prevalence of dyspnea ranges from 19-64%, depending on illness trajectory or setting, with higher rates occurring in the hospice setting (Dudgeon, Kristjanson, Sloan, Lertzman, & Clement, 2001). It is the most common and distressing symptom in patients with advanced lung cancer (Muers & Round, 1993), and frequently affects patients whose cancer originates outside of the thorax. Learning how to recognize and treat dyspnea is a vital asset for the oncology nurse. The goal of treatment is to alleviate the subjective feeling of shortness of breath and improve the patient’s quality of life.
A study including inpatients and outpatients with various stages of cancer at MD Anderson Cancer Center Pain and Palliative Care Service found that 39% of patients had constant dyspnea (Reddy, Parsons, Elsayem, Palmer, & Bruera, 2009). Reuben and Mor (1986) assessed 1700 cancer patients during their final 6 weeks of life and found that 70% suffered from dyspnea. In 30% of those patients, the symptom was rated as moderate to severe. The frequency and severity increases when death is imminent (Mercadante, Casuccio, & Fulfaro, 2000). Dyspnea is an especially difficult symptom to treat, especially for oncology nurses who are caring for patients at the end of life. This paper will describe the pathophysiology behind dyspnea, its clinical manifestations, potential differential diagnoses and finally management strategies.
Respiration is complex and is controlled by several components of the neurogenic system (Guyton & Hall, 2006). The respiratory center is located in the medulla oblongata and pons of the brainstem. It is composed of several groups of neurons, each of which is responsible for inspiration, expiration, and the rate and depth of breathing. A chemosensitive area on the medulla is highly sensitive to changes in blood PCO2 and hydrogen ion concentration. Chemoreceptors located in the carotid and aortic bodies detect changes in blood PO2. There are special mechanoreceptors in the lungs, pulmonary artery, diaphragm, and intercostal muscles that detect irritation, stretching, and congestion (Guyton & Hall).
If there is an alteration in blood pH, PCO2, PO2 or a change in the physical structure of the lung or chest wall, afferent signals are transmitted to the brain. The brain activates respiration by increasing the respiratory effort, increasing accessory muscle use, and/or increasing ventilatory requirements in an effort to bring the body back to homeostasis. The extent to which all of these responses occur can cause dyspnea (Pohl & Gaertner, 2009). In other words, chemical and mechanical changes within the body cause the patient to feel short of breath due to an increased demand of the respiratory effort elicited by the brain.
In the cancer patient, there is usually a pathological cause for these alterations in blood gases and mechanical efforts. However, the results from the National Hospice Study establish that almost 25% of terminal cancer patients complaining of dyspnea had no detectable cause (Greer, Mor, Morris, Sherwood, Kidder, & Birnbaum, 1986).
Patients may present with symptoms that correlate with chronic dyspnea or acute dyspnea. Patients often describe their dyspnea with some of the following expressions: “short of breath,” “chest tightness,” “harder for me to breathe,” or “catch my breath” (Wilcock, Crosby, Hughes, Fielding, Corcoran, & Tattersfield, 2002; Roberts, Thorne, & Pearson, 1993). For patients presenting with chronic dyspnea, they may be withdrawn, depressed, and/or isolated because of inability to participate in social activities (American Thoracic Society, 1999). For patients with acute dyspnea, they may present with pain, fatigue, fear, and/or anxiety (Bruera, Schmitz, Pither, Neuman, & Hanson, 2000). Associated symptoms, such as inspirational chest pain with acute onset shortness of breath, reports of wheezing, history fever/chills, or complaints of cough give clues to the etiology of the patient’s complaint.
Physically, patients may have tachypnea, hypoxia, tachycardia, fever, abnormal breath sounds, hemoptysis, cough, cachexia, or ascites, which can correlate with the underlying cause.
Like pain, dyspnea should be rated by the patient to establish a baseline. This will also help assess the response to specific therapies (Mahler et al., 2010). Multiple assessment tools have been developed including the Borg 0-10 scale (Borg, 1982) and the visual analog scale (Gift, 1989). The Cancer Dyspnea Scale includes twelve items that assess the patient’s sense of effort, anxiety and discomfort (Tanaka, Akechi, Okuyama, Nishiwaki, & Uchitomi, 2000). Newer scales, such as the Dyspnea-12 (Yorke, Moosavi, Shuldam, & Jones, 2009), have been developed to include the physical and affective aspects of dyspnea; the respiratory distress observation scale (RDOS) (Campbell, Templin, & Walch, 2010) is designed for patients who are unable to self-report. There have been no comparative trials demonstrating superior performance of one scale over another.
As dyspnea is a subjective experience, it is not recommended to rely solely on objective data, such as respiratory rate, use of accessory muscles, blood gases, etc. Instead, questionnaires have been designed to quantify the extent to which the patient is short of breath. Use of these questionnaires is acceptable, but the nurse should ask the patient to describe their shortness of breath with a relevant review of systems, keeping in mind that the words patients use to describe their breathing may help identify the underlying etiology. Obtaining the history, such as the past medical history and social history, is also important in identifying the cause of dyspnea.
Unfortunately, the list of differentials for dyspnea is very long, as it is a nonspecific symptom of any disease affecting the respiratory system (Phol & Gaertner, 2009). In advanced cancer patients, cardiopulmonary involvement of their cancer, such as pleural or pericardial effusion, is the most common cause. Other causes include cancer treatments, such as surgery (e.g., pneunomectomy), chemotherapy (e.g., bleomycin and/or doxorubicin), or radiation (e.g., to the chest wall). Co-morbid conditions such as COPD, emphysema, asthma, congestive heart failure and pneumonia can be present as well. It is important obtain a thorough history (medication reconciliation, past medical history including co-morbid conditions or surgical procedures) and perform the review of systems as described above.
A variety of conditions common in the cancer patient can elicit the feeling of shortness of breath or breathing discomfort in different ways. The presence of a tumor (primary/metastatic in the lung or chest wall), pneumonia, pleural effusion, or any condition causing abdominal distention (ascites, constipation/small bowel obstruction) can decrease the normal lung space. This causes dyspnea because the patient has less lung volume in which to inhale oxygen. Tumor burden(especially on the chest wall), pneumonia, and pulmonary embolism can cause pain during the respiratory cycle, which inhibits the respiratory effort of the patient. Anemia can lead to decreased ability to exchange oxygen within the alveoli; the mechanism by which this produces dyspnea is unknown. Muscle weakness or psychological distress can inhibit the patient’s physical ability to take normal breaths, forcing them to perform more work than normal (and feel more short of breath). Chronic obstructive pulmonary disease or congestive heart failure can lead to increased pulmonary venous pressure, respectively (Guyton & Hall, 2006).
The goal of treatment is to improve the subjective sensation as described by the patient. In order to treat the dyspnea, the etiology must be identified. For patients with advanced disease, this may not be possible, and management is palliative.
There are many pharmacological interventions that have been studied, most of which are targeted at correcting underlying physiological disorders, such as hypoxia and broncho-inflammation. There are, however, many other interventions that can treat the psychological, emotional and other physical factors of dyspnea.
The use of oxygen to improve dyspnea has been well-studied. If patients present with hypoxia, treatment should include supplemental oxygen therapy via nasal cannula or face mask (Nocturnal Oxygen Therapy Trial Group, 1980) in order to maintain physiological homeostasis. Mahler et al. (2010), Ben-Aharonet al. (2008), Philip et al. (2006), and Currow et al. (2009) found oxygen did not have any benefit for cancer-related dyspnea in patients without hypoxemia. Therefore, it is not recommended to administer oxygen therapy in the non-hypoxic patient. The use of air to relieve breathlessness will be discussed in the next section.
Morphine, fentanyl, hydromorphone and oxycodone are some of the most common opioids used to manage dyspnea. The mechanism of how these medications affect dyspnea is the same as that of pain relief: they reduce ventilation, anxiety and the central perception of dyspnea (and pain) by binding to opioid receptors (Jennings, Davies, Higgins, Gibbs, & Broadley, 2002). Morphine is the most common of the opioids used to relieve dyspnea, and can be administered via oral, parental, and nebulized routes. Although the oral or IV route is currently the treatment of choice, many randomized,controlled studies have been performed to determine the efficacy of nebulized morphine. These studies have found that there is no significant difference between nebulized morphine and nebulized placebo, therefore it is not recommended as first line treatment at this time (Jennings et al.; Davis, 1995; Ripamonti, Fulfaro, & Bruera, 1998; Qaseem, Snow, & Shekelle, 2008).
Elia and Thomas (2008) recommend that opioids prescribed for dyspnea should be dosed similar to the way they are for pain. However, this is not often done in the clinical setting due to fear of opioid-induced respiratory depression. Proper titration according to the half-life of the medication should be done, just at it would be done for a patient who is opioid-naïve. Titration according to pain and pharmacological guidelines will help the clinician avoid respiratory depression. Elia and Thomas advise administration of naloxone (Narcan) if respiratory depression does occur.
Like opioids, benzodiazepines, such as lorazepam and midazolam, have been used in cancer patients to help provide relief from dyspnea. Although their effects do not directly change breathing, they are effective for anxiety, panic and fear; symptoms which are often associated with dyspnea. Navigante et al. (2006) performed a randomized, single-blind study using midazolam as adjunct therapy to morphine. They found that the combination of this benzodiazepine with morphine had a positive effect on dyspnea with minimal effect on somnolence. More randomized, controlled studies aimed at assessing the efficacy of benzodiazepines, used in conjunction with other opioids, need to be performed.
There has been recent literature on the efficacy of inhaled furosemide and lidocaine for the treatment of dyspnea. Studies performed using inhaled furosemide have been small and uncontrolled, but results have been positive (Shimoyama & Shimoyama, 2002; Kallet, 2007). Larger, randomized and controlled studies need to be performed before guidelines to use these medications for treatment of dyspnea are recommended.
There is a role for oral corticosteroids if patients experience dyspnea related to bronchospasm, lymphangitic tumor spread in the lungs, radiation pneumonitits, or superior vena cava syndrome (Bruera & Currow, 2009). However, it may take up to two weeks to see a complete response, which could have limited efficacy if a patient is at the end of life.
There are few non-pharmacological interventions for the treatment of dyspnea in the cancer patient. Studies are limited in number, and most of them have only included patients with chronic obstructive pulmonary disease (COPD).
As mentioned above, the use of oxygen is unnecessary if the patient is maintaining adequate pulse oximetry. However, oxygen has been used for “comfort,” as patients frequently experience relief from the oxygen blowing on their face. Studies have been performed using room air and fans to exert the same beneficial effects, with positive results (Thomas & von Gunten, 2002; Janson-Bjerklie, Carrieri, & Hudes, 1986). In fact, Schwartzstein et al. (1987) explain facial cooling in the areas served by the 2nd and 3rd branches of the fifth (trigeminal) cranial nerve can reduce dyspnea. Therefore, use of a fan or blow-by room air can be effective in relieving breathlessness. Additionally, giving patients the ability to control air flow on their own, especially with the use of fans, may give them better control over their symptoms (Booth & Wade, 2003).
Unfortunately, there is limited evidence supporting the efficacy of pursed-lip breathing for cancer patients. Most of the studies involve patients with COPD. Neild, Soo Hoo, Roper, and Santiago (2007) performed a randomized-controlled study in patients with COPD and found significant reductions in exertional dyspnea when patients used pursed-lip breathing. This improved the patients’ overall physical function. Faager, Stahle, and Larsen (2008) also found that pursed-lip breathing improves walking endurance and oxygen saturation during walking in patients with COPD. Future studies should include patients with advanced cancer.
Although acupuncture has become more popular as a means of contemporary alternative medicine, Vickers, Feinstein, Deng, and Cassileth (2005) found it is not effective in relieving dyspnea in patients with advanced cancer. A study by Filshie, Penn, Ashley, and Davis (1996) found that acupuncture improved breathlessness, but only for a short time, in patients with cancer. Patient symptoms returned to baseline after 24 hours. It remains to be seen if any acupuncture techniques or other means of contemporary medicine practices will be effective in alleviating dyspnea in patients with advanced malignancies.
The subjective feeling of breathlessness is a distressing, common symptom in patients with cancer, especially in advanced stages. If the underlying cause is not identifiable and cannot be corrected, opioids, benzodiazepines, and oxygen (if clinically indicated) are the preferred interventions. Movement of room air via fan is also an adequate intervention. There is a significant lack of research in other non-pharmacological treatments for cancer patients; most studies have only included patients with COPD.
It is important to educate patients and family members when providing an intervention for dyspnea. Ensure patients understand medication regimens and self-care techniques when at home or in the hospice setting.
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