Breathlessness

Work of Breathing

Excess work of breathing is required to:

• Overcome the resistance of obstructive airways
• Assist active expirations when airways narrow
• Compensate for the loss of the bucket handle effect
• Overcome threshold resistance at the start of inspiration caused by intrinsic PEEP
• Compensate for alterated interaction of respiratory muscles, the flat diaphragm having to work paradoxically by pulling in the lower ribs on inspiration, thus becoming expiratory in action (Hoover's sign)

Increased WOB in spontaneous breathing patients presenting subjectively breathless and objectively with a distressed breathing pattern. The basic principle of reducing WOB is to balance supply and demand

Increased energy supply

• Nutrition
• Oxygen therapy
• Fluid and electrolyte balance
• Haemoglobin levels
• Cardiac output

Reduced energy demand

• Reduce stress
• Sleep and rest
• Positioning and relaxation
• Breathing re-education
• Mechanical support

Breathlessness - awareness of the intensity of breathing

Dyspnoea - difficult breathing occurring when it would not be expected

Tachypnoea - rapid breathing

Hyperpnoea - increased ventilation in response to increased metabolism

Hyperventilation - ventilation in excess of metabolic requirements

Breathlessness

Breathlessness, unlike pain, has a stimulus that has not yet been defined. Breathlessness arises from a variety of interlinked processes including sensory physiology and the psychology of perception (Mahler, 1990). It is composed of three mechanisms. 

• Work of Breathing
• Without disease, respiratory drive and overload are balanced. Breathlessness occurs when either drive or the load is increased. For example:
• Resistive load with increased airflow resistance
• Reduced energy supply with malnutrition
• Increased drive to breath with pneumonia
• Fatigue --> increased perception of effort
• Corticol and Subcorticol Inputs
• Uncertainty, distress, anxiety, life experiences, frustration and lack of social support
• Central chemoreceptors
• Sense a rise in PaCO2 mediated through pH

Oxygen therapy has limited effect on breathlessness as demonstrated by the limited contribution of reduced PaCO2 on breathlessness.

Cardiorespiratory disease accounts for two-thirds of cases of breathlessness (Pratter, 1989).

Characteristcs include:

• COPD
• Slow onset with productive cough
• Asthma
• Episodic on exhalation with tight chest and wheeze
• Pneumonia
• Exertional with pleuritic pain and cough

Management of Breathlessness

Handling

• Clear communication to prevent anxiety increasing oxygen use
• Consideration of closed questions
• Respect patient's knowledge - they know their optimum handling
• Maximum support and minimum speed
• Rest between each manoeuvre
• Allow a question free recovery period

Positioning

• Patients with a flat diaphragm may benefit from positions that use the pressure of the abdominal contents to dome the muscle and provide stretch to improve efficiency
• Arms are best supported to allow optimum use of the accessory muscles
• Efficient breathing positions include
• High side lying
• Sitting upright in a chair with supported arms
• Slight lean forward put stretch on diaphragm
• Typical sitting and leaning on table with pillows and feet on the floor
• Standing leaning on thighs or a windowsill
• Standing leaning sideways with hands in pockets
• Occasionally, lying flat to increase abdominal content pressure on the diaphragm

Oximetry (monitor of oxygenation on haemoglobin) is useful as biofeedback. Some severely distressed patient's benefit from being held and rocked, whilst others find neck massage a useful relaxing aid. 

Relaxation

• Facilitated by positioning, sensitive handling and sharing or information to reduce anxiety
• Patients should be warm, comfortbale and have adequate fresh air
• The effects of this hypometabolic conscious state are:
• Reduced breathlessness, anxiety and airway obstruction (Gift, 1992)
• Reduced RR, O2 consumption, HR and BP (Hodgkin & Petty, 1987)

Breathing Re-Education

• Rhythmic breathing
• Shallow breathing wastes energy because of ventilating dead space and rapid breathing because of turbulence. However encouraging deep, slow breathing beyond what is natural tends to be counter-productive as it works against elastic recoil.
• Abdominal breathing may be counter-productive with severe disease and a finely balanced breathing pattern
• Positives
• Reduced BP and breathlessness, increased inspiratory muscle strength
• Negatives
• Disruption of breathing pattern and increased WOB
• Avoid breath-holding, as it increases tension and breathlessness
• Educate that breathlessness is a non-damaging symptom, whereas smoking and lack of oxygen is damaging
• Desensitisation - perform activities that mildly provoke breathlessness and use above techniques to regain breath whilst adjusting to the sensation in order to reduce fear
• Pacing - slowing activities down to maintain stable levels and conserve energy

Breathing Exercises 

Breathing exercises to increase lung volume should be performed in cycles of no more than three of four breaths so that:

·         Maximum effort is put into each breath

·         Dizziness from over breathing is avoided

·         Shoulder tension is discouraged

Once inflated, alveoli stay open for about an hour at normal tidal breaths, so it is advisable to complete at least 10 deep breaths every waking hour to maintain lung volume (Bartlett et al, 1973).

Deep Breathing (Thoracic Expansion Exercises)

In order to facilitate deep breaths penetrating peripheral regions, optimum conditions are required:

• Relief of pain, nausea, dry mouth, discomfort, fatigue, anxiety or tension
• Avoidance of distractions
• Minimum breathlessness
• Accurate positioning, using side-lying inclined towards prone, to facilitate maximum expansion at the base of the uppermost lung

If side lying is not possible, upright sitting is the next option. If this is not possible, such as in ITU, long sitting is necessary however it allows limited expansion.

When ready, pts are asked to breathe in deeply and slowly through the nose, and then sigh out through the mouth. Breathing through the nose warms and humidifies the air, but doubles resistance to airflow so some patients may prefer to mouth breathe, especially with a NG tube.

After every four breaths, the patient should relax and regain their rhythm. RR and pattern should be observed, and change of instruction may be required before the next set. Patients should not be engaged in conversation during conversations.

Deep breathing has been shown to have the following benefits:

·         Increase lung volume

·         Increase ventilation and reduce airways resistance

·         Increase surfactant secretion, thereby improving lung compliance

·         Increase V/Q matching

·         Increase diffusion

·         Increase oxygen saturation

·         Reduce dead space ratio

Shallow breathing is inefficient. Breathless people require a special approach and should not be asked to breathe slowly.

End Inspiratory Hold

Air can be coaxed into poorly ventilated areas by interspersing every few deep breaths with breath hols for a few seconds at full inspiration. This distributes air more evenly via collateral ventilation. Ideally, inflating pressures of 30-50cmH₂O should be held for 5 seconds at 2-6 times tidal volume, but many postoperative patients cannot achieve this. The end-inspiratory hold is unsuitable for breathless patients, who should not be asked to hold their breath. It should be used with caution in patients with a tendency to bronchospasm.