Dispneia em cuidados paliativos

See also the related separate article Falta de ar.

What is dyspnoea?¹

Dispneia é a percepção angustiante do processo de respiração - seja pela frequência ou pelo esforço envolvido. É muito assustador e é um dos sintomas mais comuns nos cuidados paliativos.² It is extremely common with advancing disease, particularly late stages of doença pulmonar obstrutiva crônica (DPOC), chronic heart failure, asma, câncer, e doenças neurológicas ou musculares, e também é comum em doença renal em estágio terminal e síndrome da imunodeficiência adquirida (AIDS).³

Dyspnoea is common in people with cancer in general, but it is more common and severe in people with primary lung cancers (affecting 90% of those with advanced lung cancer.

Cuidados paliativos has been defined as 'an approach that improves the quality of life of individuals and their families facing the problems associated with life-threatening illness, through the prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain and other problems, physical, psychosocial and spiritual'.⁴ See separate article Cuidados Paliativos.

The drive to breathe and the stimulus for dyspnoea is quite complex and multifactorial:

• The main driving force of blood gases is pCO₂ rather than pO₂ (the exception being in COPD) although significant hypoxia can augment the hypercapnic drive.

• Mechanical stimuli such as pulmonary stretch and proprioceptive input from the chest wall and diaphragm are also important.

• Proprioception in the lungs and chest wall provide additional stimulus.

• Pyrexia stimulates the thalamus and can cause tachypnoea.

• Emotions (anxiety, fear, anger, etc) and arousal state also modulate breathing.

É importante distinguir causas potencialmente reversíveis daquelas que são fixas e irreversíveis.

Causes of dyspnoea

Dyspnoea is subjective and, especially in these circumstances, may correlate poorly with objective assessment of lung function including blood gas analysis and airways obstruction. It involves perception of breathlessness and a person's reaction to it, and anxiety may contribute significantly. There is no universally accepted measure of breathlessness in palliative care patients and several scales are in use, most looking at the functional impact of the breathlessness.⁵ Self-rating scales may be helpful in assessment and monitoring of response to treatment.¹

História

Should include information about:

• Previous or pre-existing conditions (comorbidities may exacerbate symptoms).

• Recent treatments - eg, radiotherapy.

• Mudanças recentes de medicação.

Questions regarding the breathlessness should include:

• Rapidity of onset (insidious and relentless vs sudden) and time course (acute or chronic, intermittent).

• Sintomas associados - por exemplo, tosse, hemoptise, estridor, sibilo, dor, fadiga.

• Relationship to exercise.

• Precipitating factors - eg, posture, exertion, pollen, emotion.

• Impacto nas atividades diárias simples - por exemplo, conversar, lavar-se, usar o banheiro, vestir-se, dormir.

• Role of carers.

• Episódios de pânico ou ansiedade.

• Impact on quality of life and any mood disturbance.

• Any known relieving factors.

Exame

Incluindo:

• Assess effort and efficacy of breathing (eg, depth of breathing, use of accessory muscles of respiration, expectoration of secretions).

• Observe o paciente em repouso e, quando apropriado, caminhando ou realizando uma pequena tarefa.

• Assessment of degree of anxiety. Chest breathing (as opposed to abdominal breathing, with use of the diaphragm) may indicate anxiety.

• Cardiac status (heart rate, rhythm, cardiac murmurs, signs of cardiac failure).

• Sinais clínicos de infecção, derrame, anemia ou cianose.

• Examination of the respiratory system based on known disease, looking for signs of stridor and progressive disease.

Investigações

Avoid unnecessary investigation: consider the stage of disease, risk-to-benefit ratio and the wishes of the patient and their family. In primary care, investigations which may be done for non-acute breathlessness include:¹

• Radiografia de tórax.

• Spirometry.

• ECG to exclude arrhythmia.

• FBC to exclude anaemia.

• Oximetria de pulso.

A gestão deve começar com a otimização do tratamento de quaisquer causas subjacentes de falta de ar, especialmente a broncoconstrição.

Non-pharmacological treatments should then be considered, in particular, positioning and breathing techniques, mobility aids, and muscle strengthening. Simple aids, such as a hand-held fan, are also important.

Para tratamentos farmacológicos, tanto a Sociedade Respiratória Europeia quanto a Sociedade Torácica Americana concluíram que, além do oxigênio e opioides, não há evidências robustas para outros agentes farmacológicos.

• Oxygen has a clear and accepted role for patients with hypoxia. However, in patients with mild or non-hypoxaemic breathlessness, the benefit derived from oxygen is similar to medical air, and there are limitations to its use (eg, safety and cost).

• Although opioids can reduce breathlessness, their effects are modest or small, and the optimal dosing, titration, and potential issues arising from long-term use (eg, safety, tolerance, dependence, misuse) remain to be determined.

• The evidence from Cochrane reviews does not support a role for benzodiazepines, except as second- or third-line treatment if opioids fail, because there is no overall evidence of benefit and some evidence of possible harms.

Geral

• Tente lidar com a falta de ar assim que o desconforto se tornar aparente, em vez de esperar até que esteja bem estabelecido. Esforce-se para estabelecer uma causa ou causas da dispneia.

• A ansiedade inevitavelmente acompanha o sintoma e pode ser aliviada explicando a situação atual e as opções de manejo. Explore medos persistentes (medos de sufocamento, engasgo, morrer durante o sono são comuns). Alguém deve permanecer com um paciente em estado agudo de angústia para oferecer segurança e possivelmente distração. Se deixado sozinho, um sino de chamada deve estar disponível.

• Useful strategies include:
  

  • Positioning - the most comfortable position is usually sitting upright with support.

  • Mantendo o quarto fresco.

  • O ar em movimento de um ventilador (de mão ou estacionário) ou de uma janela aberta ajuda a proporcionar alívio psicológico.

  • Ensino e uso de exercícios de respiração e métodos de relaxamento. Reeducação respiratória, ensinada por fisioterapeutas ou enfermeiros clínicos especializados.

  • Encourage modification of lifestyle in reducing non-essential activities, whilst trying to maintain mobility and independence as far as possible.

  • Encourage exertion to the point of breathlessness to build tolerance and maintain fitness - this will vary considerably between individuals. Pulmonary rehabilitation appears to be well-tolerated and to provide symptomatic relief in many patients with severe COPD. It is increasingly being used in a palliative setting.⁸

  • Modificações na dieta com pequenas e frequentes bebidas e refeições são melhor toleradas. Pacientes com câncer ou doença respiratória em estágio terminal frequentemente apresentam caquexia, e o aconselhamento de um nutricionista pode ser útil.

  • Mouth breathing dries the mouth and oxygen will be very dry unless it has been humidified, so attention to oral hygiene is important.

  • Complementary therapies such as aromatherapy, hypnosis and acupuncture may be helpful to some patients but the evidence base is weak.⁹

• A Cochrane Review concluded that there was evidence that chest wall vibration, neuro-electrical muscle stimulation, breathing retraining and walking aids were effective non-pharmacological interventions for relieving breathlessness in advanced stages of disease. There was mixed evidence for acupressure and acupuncture, and insufficient evidence for relaxation techniques, counselling and psychotherapy.¹⁰

Intervenções médicas

Intervenções físicas podem ajudar a aliviar ou até mesmo reverter a causa da dispneia. O grau de intervenção desejado pelo paciente pode variar, e as decisões de manejo devem ser tomadas com eles e suas famílias. Discutir possíveis eventualidades pode ajudar os pacientes a tomarem decisões importantes e informadas sobre seus cuidados futuros, como a necessidade de internações hospitalares de emergência, uso de ventilação artificial e tratamento agressivo de infecções.

Cuidados primários
Treatment of reversible or partially reversible causes of dyspnoea. For example:

• Optimising treatment of asthma, COPD, heart failure.

• Infections will aggravate dyspnoea and treatment of the infection will improve matters where the patient is not strictly terminal.

Cuidados secundários
Refer to secondary care, where appropriate, for:

• Transfusão de sangue - anaemia can exacerbate dyspnoea on exertion, and blood transfusion can be justified on this basis. One study looking at practice in six British hospices found that patients received blood transfusions in about 6% of all hospice admissions.¹¹

• Treatment of the underlying disease - for example:
  

  • Pleural effusion tapping - for recurrent effusion, pleurodesis is often effective, but it is a painful procedure. Some centres are pioneering the use of implantable access devices for recurrent tapping.¹²

  • Tapping ascites can relieve pressure on the diaphragm and improve ventilation.

  • Obstrução da veia cava superior (VCS) can arise from compression of the SVC by mediastinal tumour. In three quarters of cases it is from primary lung tumours but intraluminal thrombosis may also occur. There is dyspnoea and gross venous congestion and oedema of the head, neck and upper limbs. High-dose steroids with radiotherapy or chemotherapy may help. Dilatation, stenting and anticoagulants may also be tried.

  • O tumor pode pressionar a traqueia ou o brônquio, causando o colapso de um segmento ou de um pulmão completo. Os tratamentos incluem esteroides, radioterapia externa, quimioterapia (para câncer de pulmão de pequenas células) e tratamentos endobrônquicos, como laser, radioterapia, colocação de stents, crioterapia e dilatação com balão.

• Emergencies such as embolia pulmonar e pneumotórax may justify admission to hospital for active treatment.

Medicamentos

In some situations, physical interventions may not be possible. This is especially true of neuromuscular disease. Nonetheless, medication (including oxygen) may be useful in reducing symptoms.

Opiáceos
Reticence about the use of morphine for palliation of dyspnoea is common, especially in non-malignant disease (COPD in particular), for fear of causing respiratory depression. Oral and parenteral opiates are widely accepted as providing good symptom relief, and the risk of significant respiratory depression appears to be negligible.^{13 14}

• A morfina oral é amplamente utilizada para controlar a dispneia, embora o mecanismo de ação não seja totalmente compreendido. Os efeitos ansiolíticos e antitussígenos da diamorfina a tornam ideal para o câncer de pulmão.

• A opinião de especialistas é que a morfina oral pode ser usada com segurança para o manejo da dispneia, mesmo com DPOC, se o paciente começar com uma dose baixa e ela for ajustada de acordo com a resposta e os efeitos colaterais. Pacientes que ainda não estão recebendo morfina devem começar com doses de 5 mg a cada 4 horas/conforme necessário. Para aqueles que já estão em morfina, seja para dor ou dispneia, a dose total pode precisar ser aumentada em 30% a 50%.

• When the oral route is no longer available, administration by continuous subcutaneous infusion is acceptable. It may be combined with a benzodiazepine. The use of nebulised opiates is not recommended.

• In extreme dyspnoea and distress, intravenous or subcutaneous diamorphine is often used for more rapid relief than by the oral route.

• Considere o uso concomitante de antieméticos e laxantes quando necessário.

Ansiolíticos
There is as much reason to be cautious about respiratory depression with benzodiazepines as with opiates but they are commonly used to treat dyspnoea in palliative care. There is no evidence for a beneficial effect of benzodiazepines for the relief of dyspnoea associated with cancer or COPD.² However, guidelines continue to recommend their use for reducing anxiety associated with breathlessness, as they reduce the hypoxic or hypercapnic ventilatory responses, and the emotional response to dyspnoea.

Diazepam, lorazepam and midazolam are most frequently used. Selection is dependent on the stage of terminal disease, the severity of anxiety, and the desired onset of action. Lorazepam can be given sublingually (0.5 mg 4-6 hourly); midazolam is usually used subcutaneously (5-20 mg over 24 hours).

Tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs) may be helpful, especially for panic attacks.

Oxigenoterapia
The role of oxygen therapy for palliation of dyspnoea is unclear, and there is as yet no convincing evidence of benefit.^{15 16}

• Currently recommendations suggest oxygen should be used only where the patient is shown to be hypoxic.

• A person's need for oxygen therapy should be clinically assessed including potential risks from the oxygen use (for example, a smoker in the household). A trial of short-burst oxygen therapy may be initiated in primary care, preferably after discussion with a specialist, and should be tailored to a person's needs. Short-burst oxygen therapy should be initiated at 2 L/minute for an initial duration of treatment of between 15 and 30 minutes (although others suggest continuing until benefit is felt).

• Either a mask or nasal cannulae may suit patient preference and comfort.

Respiratory secretions
First-line treatment is hyoscine butylbromide 20 mg subcutaneously hourly as required in the final stages of life. Glycopyrronium bromide 200 micrograms 6- to 8-hourly as required and hyoscine hydrobromide 400 micrograms 2-hourly are other options.

• Fatigue, loss of appetite, pain, sweating, insomnia.

• Anxiety, depression, anger, helplessness, loneliness, intimacy issues.

• Difficulties with eating, bathing, problems with communication, reduced mobility.

• Social isolation, change of role in the family, employment, financial.