Palliation of Dyspnea in pediatrics

Abstract

Dyspnea is a complex physiologic and psychosocial symptom that is difficult to characterize and measure, but essential to treat, as it has a significant effect on quality of life. Although palliation of dyspnea in the child with chronic illness is an under-researched area, children and their families cannot wait for the research to catch up with their current needs. This article addresses several aspects of dyspnea in pediatrics palliative care, with an eye toward practical suggestions for evaluation and management.

Dyspnea is a complex physiologic and psychosocial symptom that is difficult to characterize, measure, and study and yet essential to treat because of its harmful effect on quality of life. ¹ Because dyspnea is a subjective sensation, and because the causes of dyspnea can be so complex, clinicians may become frustrated by the lack of a one-size-fits-all model for treatment. This is just as true in pediatrics as it is in adult medicine. ² Palliation of dyspnea in the child with chronic illness can become complicated by child’s difficulty in communicating degrees of dyspnea and degrees of relief, by the tension between curative and palliative care (which, unlike in adult medicine, typically persists up until the end of life in pediatrics ³ ), and by the importance of treating the child as part of a family unit. In addition, research into palliation of dyspnea in pediatrics is scarce, likely due to the difficulty of studying dyspnea in an experimental setting as well as the decreased numbers of patients with this condition at any one pediatric center. As a result, many pediatric treatments in this area are based more on practical wisdom than on a published evidentiary base. ⁴ This article will address several aspects of dyspnea and associated respiratory symptoms in pediatrics palliative care, with an eye toward practical suggestions.

The debate about the causes of dyspnea is long-standing ⁵ . Broadly speaking, dyspnea in infants and children is likely to be due to some combination of three factors: (1) an increase in the work of breathing associated with increased airway resistance or decreased compliance, (2) increasing the work of breathing associated with decreased ventilatory power such as due to muscle weakness or structural abnormalities, and (3) an increase in ventilation requirements due to metabolic acidosis, hypoxemia, anemia, or other physiologic states. ⁶ In many children with chronic respiratory illness, some aspect of each of these three factors may play a role in the sensation of breathlessness. In a chronically ill child, there may be moderate-to-low levels of dyspnea present at all times, with intermittent episodes of acute dyspnea superimposed on this chronic baseline. Treatment for the acute event of dyspnea may occupy much of the clinician’s time and energy; yet, as in adults, it is important to ask the question why the acute events occur, so that steps can be taken either to modify them earlier in their course or to prevent them altogether. Clinically, it may be difficult in some cases to isolate the specific cause of dyspnea in a particular patient; yet, this should not prevent us from making directed efforts to relieve the symptom.

Dyspnea in the pediatric context

From physiologic standpoint, dyspnea in the young school-age child and adolescent is not substantially different from the dyspnea in the adult. The great exception to this rule is during the neonatal period, when increased chest wall compliance and the presence of congenital anomalies may substantially alter the clinical picture. In the neonatal period, increased chest wall compliance may result in strikingly different breathing patterns in response to either chest wall muscle weakness or airway obstruction, and familiarity with typical breathing patterns in neonates is essential for both assessment and treatment of dyspnea. Increased chest wall compliance can lead to visible retractions in children who are not particularly distressed, and so a single sign may not be especially useful. Congenital malformations either of the cardiac or respiratory system may cause the child to adopt particular patterns of breathing, which, while abnormal, are adaptive to the particular physiologic stress; a careful search for all congenital abnormalities in the newborn period of a child who demonstrates abnormal breathing patterns is essential, if palliation of this symptom is to be successful. In particular, respiratory stress in the neonatal period should be seen as providing a metabolic challenge to the child, as increased distress diverts energy away from healing and growth. Two clinical points are worth mentioning here. First, supplemental oxygen may be used to provide average higher saturation rates that will lead to improved growth in the infant, allowing both lung growth and improved strength, which can lead to far better clinical outcomes. The understandable desire of clinicians and parents to wean the child off the nasal cannula can lead to chronic under-oxygenation during stress such as feeding and sleep; care should be taken to document appropriate oxygenation during the times of stress as part of any plan of weaning off supplemental oxygen. Second, because many neonates are on high calorie formulas in order to promote growth, the infant may be experiencing a high carbohydrate load, leading to increased production of CO₂ with the subsequent increased need for ventilation; consultation with pediatric nutritional experts, with an aim toward providing calories as fats, may reduce the ventilatory demand on the already stressed infant while providing sufficient calories for growth.

As the child ages and the chest wall matures, the physical examination of the child will exhibit the typical signs and symptoms of dyspnea as seen in adolescents and adults. Dyspnea signs in the child can range from increased respiratory rate at baseline or during exercise all the way to frank retraction, pursed lips, and obviously increased work of breathing. In many cases, the parents will report these abnormal breathing patterns to the clinician, but they may not be evident when the child is at rest in the exam room. The child may be unable to report either the symptom's occurrence or any activities that trigger or alleviate the symptom. ⁷ In addition, the child’s vocabulary to express the sensation of breathlessness may be limited, or the child may use words which point to other symptoms in order to express his distress. ⁸ In the era of widely available video cameras, parents can greatly assist the clinician by providing footage of the child in various activities, which may lead to a clearer diagnostic picture and suggest therapeutic alternatives. In many cases of chronic dyspnea, the child will habituate to the sensation, and thus may not report acutely increased dyspnea until the symptom is quite severe. Because of this habituation, the child and family may not be able to initiate simple therapy, such as rest or deliberate breathing exercises, until the child is past the point where these therapies can be effective.

Dyspnea in the pediatric palliative context

In the palliative context, in pediatrics as in adult medicine, we would do the best to adopt the motto of ‘right treatment, right time, right place’. Although reduction in dyspnea in pediatrics is enhanced by a thorough understanding of the causes, in many cases we must begin to relieve the symptoms before the exact pathophysiologic process is clear and before there is solid evidence in the pediatric literature to guide our treatment decisions. ⁹ In general, this leads to a willingness for a trial and error approach, but such an approach must be undertaken with full understanding of the parents as well as with an agreed-upon set of outcomes by which the efficacy of any given treatment can be judged. Often in pediatrics, we are balancing the burden of treatment against the expected outcome for the child. Doing so with children is sometimes more complicated than with adults, since a child cannot speak for himself and since our desire to rescue the child is so strong. Such uncertainty can lead both to overly aggressive treatments that are burdensome to the child (even though they result in physiologically measurable changes) and to under-treatment of symptoms, and thus continued suffering, while we pursue a solely curative approach. Contemporary pediatric palliative care clinicians are used to practicing in this tension between under and overtreatment; in general, the best approach is clarity about the objectives of treatment and frequent revisiting of the child’s and parent’s experience with an eye toward balancing the burdens of treatment and symptoms.

In order to illustrate this, we need to look no further than the current controversy surrounding provision of assisted ventilation for children with spinal muscular atrophy type I. ^10–12 Current clinical practice in this area is in a state of flux: a prior consensus existed that chronic mechanical ventilation for these children was excessively burdensome in view of their prognosis, and yet improvements in both ventilation and airway clearance techniques and the increased acceptability of assisted ventilation in the home environment have led to expanded use of ‘noninvasive’ ventilation for these children. ¹³ As of 2012, the standard of care for these children is changing. ^{14 ,15} If chronic assisted ventilation is going to be used, it should be instituted early in order to prevent remodeling of the chest wall, which places the child at an even greater mechanical disadvantage. There is an emerging evidence base for the provision of noninvasive ventilation in these children, and clinicians who do not have experience with this would be well recommended to contact those with greater experience before embarking on an ad hoc clinical regimen. ¹⁶

A second example with a different diagnosis arises in the shifting consensus regarding chronic ventilation, both invasive and noninvasive, of children and adolescents with cystic fibrosis. Prior to the advent of widely available lung transplantation, a consensus existed that to provide ventilation for the patient during the period of progressive respiratory failure was excessively burdensome in light of the prognosis. ¹⁷ However, the increasing use of various modes of ventilation as ‘bridges’ to transplant has led to increasing use of ventilation of patients with cystic fibrosis regardless of their transplantation status. Again, early discussion of the use of assisted ventilation in patients with cystic fibrosis with both the patient and the parent is essential, in particular the establishment of specific outcome goals for the therapy. The evidence is clear that such discussions are frequently delayed either until the adolescent or young adult patient cannot participate or until the alternatives are few. ¹⁸ Humane care for these patients requires that we clinicians break through our reluctance to discuss end-of-life care planning and that we develop flexible and disease appropriate regimens, including time-limited treatments combined with aggressive symptom relief, which provide comfortable and viable options for patients and families facing difficult choices. ¹⁹

Assessment strategies in pediatric dyspnea in the palliative context

Chronic dyspnea can be associated with a wide variety of pediatric conditions, only some of which are life-limiting. In addition, some life-limiting conditions can be accompanied by common pediatric diagnoses, most commonly asthma and/or gastroesophageal reflux with aspiration, which may produce either chronic or acute dyspnea in the otherwise chronically ill child.

The most common cause of acute episodes of dyspnea in the chronically ill child is likely to be a viral infection, and this will be readily apparent by both history and physical. Evaluation and treatment of asthma and gastroesophageal reflux are excellent first steps when faced with a child with an abnormal breathing pattern, regardless of the underlying diagnosis. ²⁰ Evaluation of cardiac function (including evaluation for previously occult congenital heart disease) should be the next step, ²¹ closely followed by the evaluation of upper airway dysfunction such as subglottic or tracheal stenosis, vocal cord dysfunction, and vascular or other anomalies of the airway, including retained foreign body in mobile toddlers. ²² Metabolic dysfunction such as acidosis or anemia would be the next step in the diagnostic cascade followed by less frequent diagnoses such as interstitial lung disease, pulmonary hypoplasia, or pulmonary embolus. Next, especially in children with a history of troubled sleep or snoring, would be evaluation of abnormal sleep patterns using polysomnography. Abnormal breathing, which may be evident only during sleep, may be indicative of abnormalities in central control of ventilation that can be uncovered during polysomnography. Finally, some children may be dyspneic due to obesity, deconditioning, or, in some teenagers, anxiety or other psychological states. Exercise tests may reveal the last few conditions, if performed under observation by the clinician.

Baseline pulmonary function testing for dyspnea may or may not be revealing. While assessment of obstructed flow can be helpful in children with undiagnosed asthma, many children with chest wall abnormalities or other developmental conditions may be either unable to complete pulmonary function testing or the results may be difficult to compare with established norms. Assessments of respiratory muscle strength generally require substantial cooperation from the child, and may measure either maximum inspiratory or expiratory pressures, maximum sniff pressure, maximum cough pressures, or other maneuvers. Changes in pulmonary function testing may or may not be reliable as outcome measures for treatment of dyspnea; in some cases, substantial improvement in pulmonary function testing may be present without relief of the symptoms, again indicating the complexity of the sensation of dyspnea.

Measurement of dyspnea in children is understudied; however, there are some bright spots in the literature. The development of dyspnea scales specific to pediatrics, such as the Dalhousie Dyspnea Scale and others, is encouraging. ^{23 ,24} It is likely that the best use of such scales will be before and after the use of treatment modalities, rather than for the comparison of one child to another or as a tool to diagnose dyspnea in otherwise difficult cases.

Management strategies in pediatric dyspnea in the palliative context

Appropriate management strategies for dyspnea in the infant and child vary from psychosocial to phamacological to the mechanical. Choosing where to land on that spectrum is part of the art of clinical medicine, as there is no one-size-fits-all strategy. One good approach is to match the intensity of the intervention with the intensity of the symptom, escalating until relief is achieved, as we might do with the management of acute and chronic pain. In general, willingness to combine a variety of therapies and to set time-limited trials of therapy with agreed upon outcomes is a good approach. ²⁵

For mild dyspnea, psychological and behavioral interventions are frequently tried first. ²⁶ In addition to purely psychological maneuvers such as self hypnosis and antianxiety techniques, referral to physical therapy for strength conditioning, particular upper body conditioning, can be appropriate in some patients and give excellent results. ²⁷ An additional approach worth mentioning is the use of fans to blow directly on the face in episodes of dyspnea. It is unclear what the mechanism of relief may be (perhaps stimulation of the trigeminal nerve or alteration of the perception of airflow relative to the work of breathing?) and yet many patients do indeed report improvement in breathlessness and the therapy has no side effects. For mild dyspnea that does not respond to these approaches, the next step will depend on the clinical characteristics. For patients with obvious hypoxemia, institution of supplemental oxygen is advised. Care should be taken regarding the institution of supplemental oxygen in those children with chronic carbon dioxide retention, as would be done in adults.

For those with moderate dyspnea, treatment modalities can be added including noninvasive positive pressure ventilation either by means of Continuous Positive Airway Pressure (CPAP) or Bi-Level Positive Airway Pressure (BiPAP), depending on the child’s clinical condition. ²⁸ For some children, particularly those with certain types of neuromuscular weakness, sleeping with BiPAP at night provides respiratory muscle rest and a more active day. Clinical anecdotes suggest that children with chronic obstructive hypercarbia or hypoxemia at night due to neuromuscular disease can have a substantially increased quality of life, with improved growth and school performance, with the institution of home BiPAP during sleep. Again care should be taken with the institution of these therapies and management by means of polysomnography is advised. In the absence of polysomnography, instituting supportive therapy at night may be done during a hospital stay so that the patient can be more closely monitored.

Airway clearance techniques can also be used to relieve dyspnea in the child, and can be effective both in those children with excess mucus production and in those children with insufficient cough strength to clear normal airway secretions. Methods of airway clearance have to be tailored to the individual child’s condition, and range in invasiveness from postural drainage or active cycle breathing to use of the mechanical ‘in-exsufflator.’

Chronic negative pressure ventilation using either a cuirass (frequently called a ‘turtle' by children and families) or a raincoat (a closed poncho which surrounds the child) is one possible option. Negative pressure ventilation devices can be difficult to fit to the chest wall or body of the child, and there has been decreased use of these devices in recent decades. However, some children with chronic dyspnea thrive using negative pressure devices, either only for sleep or for longer periods.

Chronic positive pressure ventilation should begin with the assessment of suitability for so-called noninvasive methods. We should recognize that the term ‘noninvasive' is appropriate only from the perspective of the clinician, and that many patients and parents regard this technique of ventilation as highly ‘invasive' in their quality of life. However, the availability in the last decade of smaller-sized facial interfaces and more portable equipment has made noninvasive ventilation more practical and easily tolerated by patients and families alike.

Chronic positive pressure ventilation using tracheostomy has the downside of limiting speech for many children, although certainly not for those who can adapt to speaking valves. One disadvantage of chronic positive pressure ventilation using tracheostomy is the irreversibility of the procedure. With non-invasive ventilation, if there is no relief of symptoms, the therapy can be easily discontinued. With tracheostomy, the decision to halt chronic ventilation becomes more difficult, although there is no physiological reason for this. It may be that discontinuing use of assisted ventilation in children with a tracheostomy is more difficult for cultural or psychological reasons, although no study has been performed to examine this phenomenon.

Pharmacological interventions for dyspnea are similar to those in adults. ²⁹ Pharmacological interventions for dyspnea in children are similar to those in adults. Opioids are the cornerstone of therapy. In patients with chronic respiratory insufficiency, there may be some hesitancy to use medications that can cause central respiratory depression. One common concern is that a decrease in respiratory rate following administration of opioids reflects suppression of central respiratory drive; in fact, what it more likely reflects is relief of dyspnea with the fall in a respiratory rate elevated by distress. Careful observation and use of objective standards to measure improvement can help lessen this inappropriate fear of opioid use. Wise use of opioid medications, beginning at low doses, has been shown to be highly effective and can be used in a way which minimizes side effects. A standard starting dose for dyspnea for the ‘opioid-naive’ patient is 0.025 mg/kg intravenously, which is about one fourth of the starting dose for pain therapy. The dose can then be increased as needed for relief, using agree-upon standards for changes in symptoms.

For chronic dyspnea, oral opioid preparations are preferable to intravenous, again starting at doses about one-fourth that used for pain and increasing for good effect. Although there have been published reports on the use of nebulized morphine, there is as yet no strong clinical evidence to support its use. Benzodiazepines can control the anxiety which often accompanies breathlessness, and so provide relief in some cases, but they are not recommended as stand-alone agents in the management of dyspnea in children.

Conclusion

Dyspnea in the chronically ill child is a complex symptom that can be highly subjective, difficult to assess and treat, and deeply frustrating for the patient, parent, and clinician. It is an understudied phenomenon in an era of evidence-based medicine. However, we cannot wait until we understand this complex problem completely before taking action; patience, open communication, and a willingness to explore possible options using time-limited trials with clearly agreed-upon outcomes is the best approach we can offer our patients, while we wait for our knowledge to catch up with their needs. ³⁰