Next session

Next session is the 8th July at 4pm and the classroom is 412

Mary

Heart Failure

Heart failure

Heart failure is a chronic, progressive cardiovascular disorder that causes fluid buildup in the heart from impaired myocardium contractility. It usually occurs from a damaged left ventricle, but it may also result from right ventricular damage. It's classified according to physical limitations.

Pathophysiology

Left-sided heart failure occurs when ineffective left ventricle contractile function results in decreased cardiac output. Blood backs up into the left atrium and lungs, causing pulmonary congestion. Right-sided heart failure occurs when ventricular injury impedes contractibility of the right ventricle's cardiac cells. Ineffective ventricular pumping leads to blood backup in the right atrium and, eventually, the peripheral circulation.

Complications

Acute

■ Pulmonary edema

■ Acute renal failure

■ Arrhythmias

Chronic

■ Activity intolerance

■ Renal impairment

■ Cardiac cachexia

■ Metabolic impairment

■ Thromboembolism

Assessment (only potential abnormalities listed)

Nursing history by Functional Health Pattern

Health perception and management

■ History of heart failure, hypertension, or cardiovascular disease

■ Noncompliance with prescribed diet, medications, or activity restrictions

■ Peripheral edema or fatigue (common)

Nutrition and metabolism

■ Anorexia (common)

■ Nausea or vomiting

■ Weight loss and cachexia

Elimination

■ Altered urinary patterns

■ Constipation

■ Nocturia

Activity and exercise

■ Inability to participate in exercise or leisure activities (common)

■ Difficulty participating in activities of daily living (ADLs)

Cognition and perception

■ Difficulty understanding problem and treatment protocols

■ Headaches, confusion, or memory impairment

Sleep and rest

■ Disturbed sleep patterns

■ Use of two or three pillows during sleep

■ Paroxysmal nocturnal dyspnea

Self‑perception and self‑concept

■ Body image disturbances

Sexuality and reproduction

■ Decreased libido and impotence or orgasmic dysfunction

Roles and relationships

■ Difficulty fulfilling role responsibilities

Coping and stress management

■ Anxiety

■ Depression, withdrawal

Physical Examination

General appearance and nutrition

■ Sitting up and leaning forward

■ Shortness of breath, inability to answer questions (during acute episode)

Mental status and behavior

■ Altered level of consciousness (based on degree of hypoxia)

■ Anxiety and restlessness

Integumentary

■ Dependent edema of lower extremities

■ Cyanosis

■ Clubbing of fingers (in chronic heart failure)

■ Jaundice (in those with long-term heart failure who develop cardiac cirrhosis)

Respiratory

■ Dyspnea

■ Crackles (usually bibasilar)

■ Cough (may produce frothy, blood-tinged sputum with episode of pulmonary edema)

■ Progressive bilateral diminishing of breath sounds

Cardiovascular

■ Tachycardia

■ S₃

■ S₄ with summation gallop (with tachycardia)

■ Atrial and ventricular arrhythmias

■ Jugular vein distention

■ Systolic murmur (in advanced heart failure)

■ Decreased peripheral pulses

■ Parasternal heave

■ Point of maximal impulse shifted to the left

Gastrointestinal

■ Abdominal distention

■ Vomiting

■ Tenderness over liver

■ Liver enlargement

Neurologic

■ Increased irritability

■ Impaired memory

■ Confusion (rare)

Musculoskeletal

■ Weakness and easy fatigability

■ Muscle wasting (rare)

Renal and urinary

■ Decreased urine output

Diagnostic studies

■ Serum electrolyte levels reveal electrolyte imbalances from fluid shifts, diuretic therapy, or response of organ systems to decreased oxygen and increased congestion.

■ Arterial blood gas (ABG) measurements indicate lowered partial pressure of arterial oxygen (Pao₂) related to pulmonary congestion; elevated partial pressure of arterial carbon dioxide (respiratory acidosis) may be from pulmonary edema or hypoventilation.

■ Blood urea nitrogen (BUN) and creatinine levels are elevated, reflecting decreased renal function.

■ Bilirubin, aspartate aminotransferase, and lactate dehydrogenase levels are elevated, indicating decreased liver function.

■ B-type natriuretic peptide level is elevated (level indicates the degree of heart failure).

■ Urinalysis reveals proteinuria and elevated urine specific gravity.

■ Chest X‑ray reveals an enlarged cardiac silhouette (common), distended pulmonary veins from redistribution of pulmonary blood flow, and interstitial and alveolar edema (common).

■ Echocardiography can identify valvular abnormalities, chamber enlargement, abnormal wall motion, hypertrophy, pericardial effusion, and mural thrombi.

■ Multigated blood pool imaging scan demonstrates decreased ejection fraction and abnormal wall motion.

Nursing care plan

Nursing diagnosis		Nursing priorities
Decreased cardiac output related to decreased contractility, altered heart rhythm, fluid volume overload, or increased afterload		■     Maintain optimum cardiac output.
Impaired gas exchange related to fluid accumulation in the lungs and at the alveolar level		■     Maintain optimal ventilation and oxygenation.
Excess fluid volume related to decreased myocardial contractility, decreased renal perfusion, and increased sodium and water retention		■     Optimize and monitor volume status and electrolyte balance.
Activity intolerance related to decreased cardiac output and impaired gas exchange		■     Increase activity level without exceeding cardiac energy reserves.
Imbalanced nutrition: Less than body requirements related to decreased appetite and dietary restrictions		■     Ensure adequate intake of nutrients needed for healing and increased energy requirements.
	Other potential nursing diagnoses: Ineffective therapeutic regimen management related to health beliefs, a negative relationship with caregivers, or the complexity of the regimen ■ Deficient knowledge (treatment regimen) related to lack of exposure to information

Decreased cardiac output related to decreased contractility, altered heart rhythm, fluid volume overload, or increased afterload

expected outcome

The patient will maintain optimal cardiac output as evidenced by stable vital signs, minimal or absent peripheral edema, normal peripheral pulses, warm, dry skin, and stable cardiac rhythm.

Suggested NOC Outcomes

Cardiac pump effectiveness; Circulation status; Tissue perfusion: Abdominal organs; Tissue perfusion: Peripheral; Vital signs

Nursing interventions

Intervention type	Intervention	Rationale
Independent	Monitor and document cardiovascular status: heart rate and rhythm, heart sounds, blood pressure, pulse pressure, and the presence or absence of peripheral pulses. Compare to the baseline assessment. Report abnormalities to the practitioner.	Monitoring cardiac status allows for rapid identification and treatment of decreased cardiac output.
Collaborative	Administer cardiac medications, as ordered, and document the patient's response. Observe for therapeutic and adverse effects.	Pharmacotherapeutic agents may relieve heart failure by altering preload, contractility, or afterload—major determinants of cardiac output. However, many of these agents have narrow therapeutic ranges or adverse effects that can worsen the underlying disease.
Independent	Observe for signs and symptoms of hypoxemia, such as confusion, restlessness, dyspnea, arrhythmias, tachycardia, and cyanosis. Ensure adequate oxygenation with proper positioning (semi‑Fowler's or upright) and supplemental oxygen, as ordered.	Prompt detection of hypoxemia allows timely intervention. The semi‑Fowler position prevents abdominal organs from pressing on the diaphragm and interfering with its movement. An upright position permits a severely dyspneic patient to use accessory muscles for breathing; it also redistributes blood to dependent areas, decreasing blood return to the heart and reducing preload in a patient with volume overload. A patient who has difficulty maintaining an arterial oxygen level above 60 mm Hg may benefit from supplemental oxygen.
Independent	Ensure adequate rest by monitoring the noise level, limiting visitors, grouping diagnostic tests, and spacing therapeutic interventions.	Rest reduces myocardial oxygen consumption.
Collaborative	Monitor fluid status: ■     Obtain accurate daily weight. ■     Maintain accurate intake and output record. ■     Assess lungs for crackles, decreased sounds, and a change from vesicular to bronchial breath sounds. ■     Assess for dependent edema and increasing dyspnea. ■     Assess for signs of dehydration.	Fluid volume may be increased from the heart's inability to maintain adequate flow and pressure through the kidneys: ■     Rapid weight gain (1 to 2 lb [0.5 to 1 kg] per day) indicates fluid retention and the need for increased diuresis. ■     Accurate intake and output records can warn of early fluid excess. ■     Crackles, decreased sounds, and bronchial breath sounds indicate fluid in the lungs and signal increasing left‑sided heart failure. ■     Dependent edema and dyspnea are signs of increasing right‑sided and left‑sided heart failure, respectively. ■     Fluid volume may be decreased from excessive diuresis.
Independent	Assess for increasing confusion.	When cardiac output is decreased, cerebral perfusion is diminished, producing confusion.
Independent	Decrease the patient's fear and anxiety by providing information and by eliciting concerns and responding to them.	Fear and anxiety activate the sympathetic nervous system and increase heart rate, myocardial contractility, and vasoconstriction. All these factors increase myocardial oxygen consumption.
	[Additional individualized interventions]

Suggested NIC Interventions

Anxiety reduction; Cardiac care; Cardiac care: Acute; Hemodynamic regulation; Medication administration; Oxygen therapy; Respiratory monitoring; Shock management: Cardiac; Vital signs monitoring

Impaired gas exchange related to fluid accumulation in the lungs and at the alveolar level

Expected Outcome

The patient will exhibit improved gas exchange as evidenced by improved ABG values, decreased dyspnea, decreased lung congestion, and no cyanosis.

Suggested NOC Outcomes

Respiratory status: Gas exchange; Vital signs

Nursing interventions

Intervention type	Intervention	Rationale
Independent	Assess respiratory status (rate, rhythm, and depth) every 2 to 4 hours and report abnormal findings: ■     Assess breath sounds. ■     Assess for absence or presence of cyanosis.	Respiratory rate, rhythm, and depth of respirations indicate severity of shortness of breath and respiratory distress: ■     Abnormal lung sounds can indicate presence of fluid buildup in the lungs. ■     Presence of cyanosis is a late indicator of hypoxia.
Collaborative	Administer oxygen as ordered.	This will help to improve oxygenation.
Collaborative	Monitor ABGs and pulse oximetry every 2 to 4 hours and report changes.	Abnormal Pao2 and arterial oxygen saturation indicate severity of hypoxia.
Collaborative	Administer diuretics as ordered.	Diuretics help promote fluid loss.
	[Additional individualized interventions

Suggested NIC Interventions

Acid-base management: Respiratory acidosis; Acid-base management: Respiratory alkalosis; Oxygen therapy; Respiratory monitoring; Vital signs monitoring

Excess fluid volume related to decreased myocardial contractility, decreased renal perfusion, and increased sodium and water retention

Expected outcome

The patient will obtain approximate balance between intake and output.

Suggested NOC Outcomes

Fluid balance

Nursing interventions

Intervention type	Intervention	Rationale
Independent	Monitor fluid balance (hourly fluid intake and output and 24‑hour fluid balance). Weigh the patient daily.	Intake and output monitoring provides an objective method of tracking fluid gains or losses, while 24‑hour summaries indicate net fluid balance. Daily weight measurements can reflect fluid gain or loss.
Collaborative	Administer I.V. solutions, as ordered. Avoid saline solutions.	The type and amount of I.V. fluid ordered depends on the patient's current condition and the cause of heart failure. Saline solutions can cause water retention.
Collaborative	Implement fluid restriction if ordered: ■     Explain the rationale to the patient and his family. ■     Establish a fluid intake schedule and teach the patient how to record oral fluids and use microdrip tubing or an infusion pump to control I.V. intake.	Fluid restriction helps limit excessive preload: ■     The patient and his family are more likely to comply with fluid restriction if they understand the reasons behind it. ■     Regular fluid intake, consistent measurements, and use of microdrip tubing or infusion devices help ensure maintenance of fluid restrictions.
	[Additional individualized interventions]

Suggested NIC Interventions

Fluid management; Fluid monitoring; Hemodynamic regulation

Expected outcome

The patient will exhibit electrolyte levels within expected parameters.

Suggested NOC outcome

Electrolyte & acid/base balance

nursing interventions

Intervention type	Intervention	Rationale
Independent	Monitor BUN and creatinine level and report increasing values.	BUN and creatinine levels reflect decreased renal perfusion from worsening heart failure. The BUN level rises disproportionately; the BUN‑creatinine level ratio can increase from the normal of 10:1 to as high as 40:1.
Independent	Monitor sodium and potassium levels. Report abnormal values and signs of imbalances.	Identification of abnormal values prompts rapid treatment to correct electrolyte levels.
Collaborative	Administer electrolyte supplements as ordered and indicated. Recheck levels after treatment.	Administration of electrolyte preparations can correct an imbalance and prevent complications.
	[Additional individualized interventions]

Suggested NIC interventions

Electrolyte management; Electrolyte monitoring

Activity intolerance related to decreased cardiac output and impaired gas exchange

expected outcome

The patient will demonstrate an improved level of activity and carry out ADLs to the fullest extent possible.

Suggested NOC Outcomes

Activity tolerance; Endurance; Energy conservation; Self-care: Activities of daily living (ADL); Self-care: Instrumental activities of daily living (IADL)

Nursing interventions

Intervention type	Intervention	Rationale
Independent	Determine cardiac stability by evaluating blood pressure, heart rhythm and rate, and indicators of oxygenation, such as level of consciousness and skin color.	Activity increases myocardial contractility, heart rate, blood pressure, and myocardial oxygen consumption and can compromise cardiac output.
Collaborative	When the patient is stable, institute a graduated activity program according to facility protocol. Evaluate the patient's tolerance of new activities.	Gradual increase in activity will promote circulation and endurance and reduce the risk of immobility. A too‑rapid activity increase can exacerbate heart failure. Activity goals that exceed the patient's capabilities may cause a psychological setback.
Independent	Alternate activity with rest periods.	Regular rest prevents depletion of cardiac reserves.
Collaborative	Administer anticoagulants as ordered. Monitor appropriate coagulation studies and report results that exceed set limits.	Anticoagulants prevent clot formation that may cause deep vein thrombosis.
	[Additional individualized interventions]

Suggested NIC Interventions

Activity therapy; Energy management; Exercise promotion: Strength training; Nutrition management; Self-care assistance

Imbalanced nutrition: Less than body requirements related to decreased appetite and dietary restrictions

expected outcome

The patient will meet daily calorie requirements.

Suggested NOC Outcomes

Appetite; Nutritional status; Nutritional status: Food & fluid intake; Nutritional status: Nutrient intake; Weight control

Nursing interventions

Intervention type	Intervention	Rationale
Independent	Keep a daily record to monitor calorie intake. Consult the dietitian to identify the patient's calorie needs.	Evaluating what a patient eats daily can help formulate an appropriate dietary plan
Independent	Assess the patient's food preferences and cultural influences on diet.	The patient may be more compliant if food preferences are considered whenever possible. Cultural influences should be incorporated into the dietary plan whenever possible.
	[Additional individualized interventions]

Suggested NIC Interventions

Diet staging; Fluid monitoring; Nutrition management; Nutritional monitoring

Teaching checklist

■ Disease process and treatment plan

■ Signs and symptoms of fluid overload

■ Risk factor reduction

■ Medications (use, dosage and administration, schedule, and possible adverse effects)

■ Dietary modifications

■ Activity restrictions

■ Follow-up care

■ Medical follow-up and instructions

■ Community agencies and support groups

■ Common emotional changes

exam warning

The examination timetable for students will be published on the Examinations Office Notice Board on the first floor of the George Moore building and on the Exams Guide Web pages (http://www.gcu.ac.uk/student/exams/index.html) within the next 7 days.

please check this out 

Ethics

http://www.nmc-uk.org/Documents/Standards/nmcTheCodeStandardsofConductPerformanceAndEthicsForNursesAndMidwives_TextVersion.pdf

Next academic support session

Everyone - next session will be 8th July at 4pm I will book a room
We will be looking at crush injury
M

DNAR links

http://www.resus.org.uk/pages/dnarrstd.htm

http://www.nursingtimes.net/nursing-practice-clinical-research/a-review-of-nurses-attitudes-towards-dnar-decisions/200260.article

http://www.nursingtimes.net/nursing-practice-clinical-research/a-debriefing-approach-to-dealing-with-the-stress-of-cpr-attempts/199518.article

assessment of breathless patient

Assessment of breathless patient Monitor respiratory rate, rhythm and depth. Also monitor patient’s chest movement, air entry and oxygen saturation. Chest movement should be equal, bilateral and symmetrical. Air entry should be assessed by observing, listening to and feeling the chest. Breath sounds should be bilateral and audible in all lung zones. Arterial oxygen saturation can be monitored using pulse oximetry.

Assess for the noisy respirations e.g.

1.    Highly pitched ‘croaking’ respiration during inspiration is caused by laryngeal or tracheal obstruction.

2.    Musical sound ‘wheeze’ during expiration occurs when air flows through narrowed bronchi and bronchioles.

3.    ‘Ratly’ sound from chest occurs in pulmonary oedema.

4.    ‘Gurgling’ sound results in presence of fluid in upper airway.

Healthy spontaneous breathing is quiet and accomplished with minimal effort. The amount of energy expended on breathing depends on the rate and depth of breathing, airway resistance and the ease with which the lungs can be expanded. Signs of increased work of breathing include an increase in respiratory rate, noisy respiration and the use of accessory muscles such as abdominal muscles. The normal respiratory rate in adults is approximately 12-18 breaths per minute; however, breathless patients can experience different breathing patterns:

Tachypnoea is an abnormally rapid rate of breathing (>20 breaths per minute) and is usually one of the first indications of respiratory distress.

Bradypnoea is an abnormally slow rate of breathing (<12 breaths per minute) which can indicate severe deterioration in the patient’s condition.

Some patients may exhibit a Cheyne-Stokes pattern of breathing, which is characterised by periods of apnoea (cessation of respiration) alternated

with periods of hyperpnoea (overbreathing). This may be caused by left ventricular failure and cerebral injury.

Ventilation:The assessment of heart rate, skin colour and the patient’s mental status can help to provide an indication of the adequacy of ventilation. Hypoxaemia can have the following effects:

Heart rate – the breathless person will experience tachycardia initially, but severe hypoxia can cause bradycardia.

Skin colour – the skin will appear pale. Hypoxia causes catecholamine release and vasoconstriction.

Mental status – symptoms include agitation, drowsiness, confusion and impaired consciousness.

Accurate assessment of the characteristics of each individual’s breathlessness includes the severity, timing, related chest pain, cough and sputum. These characteristics help to determine the most appropriate treatment and also help in diagnosis. E.g timing: Severe asthma and LVF are experienced more commonly at night.

The monitoring of vital signs, arterial blood gases, electrocardiogram (ECG), X-ray of the chest, pulmonary function tests, exercise testing, computerised axial tomography (CAT) scan of the chest and echocardiogram will also assist in identifying the cause of breathlessness.

Signs and Symptoms

Breathlessness The first symptom most patients experience in cardiac failure is breathlessness. The left ventricle fails to eject sufficient volumes of blood into the systemic circulation there is an increase in LVEDP (left ventricular end diastolic pressure), which results in the elevation of pressure in the pulmonary vasculature and may lead to pulmonary oedema.

Nocturnal dyspnoea is another symptom of heart failure. When a patient lies down there is an increase in left ventricular filling pressures because of the increase in venous return from the peripheral extremities. Congestion of blood in the heart results in an increase in systemic venous pressure leading to widespread oedema.

Oedema Oedema is an excessive accumulation of fluid in the interstitial spaces of the tissues. Patients with congestive heart failure, can develop systemic oedema, which ranges from mild ankle oedema to gross oedema of the legs, abdomen, sacrum and scrotum.

Fatigue and lethargy Many patients with heart failure experience fatigue and lethargy, which may be caused by muscle wasting, dyspnoea and anorexia

In severe heart failure, patients may not be able to sleep because of shortness of breath and anxiety. Disturbance in sleep patterns and reduced blood flow to the brain may also cause confusion

Nursing care

When patients are admitted to hospital with heart failure it is important that nurses assess them, identify their main problems and plan their care.

Positioning may help relieve breathlessness, the most common symptom that patients present with. Sitting the patient in an upright position supported

by pillows encourages the lungs to expand, which may help to relieve breathlessness Rest is important because it reduces the oxygen demand on the heart. Oxygen therapy should be commenced as prescribed; this can be administered via nasal cannula or a face mask. The combination of sodium retention and breathlessness in heart failure causes a reduction in usual salivary excretions and makes the patient’s tongue dry and rough. The administration of humidified oxygen can help to reduce this effect because it moistens the oxygen. Regular mouth care is necessary to prevent dryness of the mouth and lips.

Diuretic therapy and fluid restriction may be prescribed to reduce and/or relieve the oedema. Once commenced, a strict record of all fluid intake and output should be kept and daily weight should be recorded. This is necessary

to assess the effectiveness of drug therapy.

The patient’s vital signs should be monitored and recorded as appropriate for their condition. Nursing documentation should be clearly charted and include the details of oxygen delivery: date and time the patient was commenced on oxygen therapy; the type of delivery device used; the oxygen flow rate; respiratory effort; breath sounds; skin colour; and any changes in the patient’s mental state.

One of main roles in oxygen therapy is to support, reassure and gain the patient’s confidence to maintain compliance with treatment. To promote and ensure patient safety during oxygen administration, nurses should ensure that the correct procedure is followed according to local guidelines. The effectiveness of oxygen delivery needs to be monitored regularly as the patient’s requirements for oxygen might fluctuate as his or her condition changes.

Patients with severe heart failure may not be able to maintain personal hygiene. The nurse needs to assess patients to see how much they can do and what the nurse needs to assist them with. These patients will require assistance with all care, which includes full bed bath, eye care, mouth care and urinary catheter care (if one is in place). This may cause embarrassment for patients so the nurse needs to be aware of this and be sympathetic, caring and maintain the patient’s dignity at all times.

From admission, it is vital that these patients are nursed on a pressure-relieving mattress to try to prevent the development of skin damage. By using a pressure ulcer assessment tool such as Waterlow (1995), the nurse can identify if the patient is at risk of developing an ulcer, and what treatment or equipment is necessary to help prevent this (Harding 1999). The patient should be encouraged to move position frequently or, if he or she is unable, nursing staff should assist in changing the patient’s position. This will help to prevent the formation of pressure ulcers.

Treatments/Drugs

1. Diuretics Therapy: Diuretics are the first-line treatment for patients with heart failure, and help to relieve the symptoms of shortness of breath and oedema. Furosemide and bumetanide (loop diuretics) work in the loop of Henle by increasing the secretion of sodium and water. The most common adverse effects of these drugs are hypokalaemia (low potassium) and dehydration. Regular monitoring of the patient’s urea and electrolytes is necessary to detect hypokalaemia. This can be treated with amiloride and spironolactone (potassium-sparing diuretics) or potassium supplements. Care should be taken when administering intravenous (IV) furosemide because it may cause tinnitus and deafness if given too quickly. IV infusion of furosemide should be given at a rate of 4mg/minute, however, single bolus dosages up to 50mg can be given more rapidly (British National Formulary (BNF) 2004).

Bendroflumethiazide and Metolazone (thiazides) which act by inhibiting sodium and chloride reabsorption in the distal tubule (Figure 1), which results in increased sodium and water secretion.

amiloride and spironolactone work by increasing sodium and chloride excretion in the distal tubule and cause the retention of potassium. However,

this group of diuretics is relatively weak and is usually prescribed in conjunction with thiazides or loop diuretics.

2. ACE inhibitors: ACE inhibitors such as captopril, ramipril and enalapril work on the renin-angiotensin-aldosterone system. Renin is released from the

kidney in response to a drop in blood pressure, and converts angiotensin I to angiotensin II, a potent vasoconstrictor, and in addition stimulates the release of aldosterone, causing the retention of sodium and water. This leads to an increase in the circulating blood that, in turn, leads to an increase in blood pressure. By inhibiting angiotensin II, the blood pressure is lowered. Caution should be taken when administering ACE inhibitors, especially for the first time, because they can cause a profound drop in blood pressure. It is recommended that a small ‘trial dose’ should be given to the patient to assess the effects of the medication. The patient should be lying down and under close observation with regular monitoring of his or her blood pressure.

3. Beta-blockers:  Beta-blockers such as atenolol, bisoprolol and propranolol were once contraindicated in patients with heart failure. However, medical trials have shown that selective beta-blockers, such as carvedilol, reduce mortality, and, in combination with diuretics and ACE inhibitors, improve the symptoms of left ventricular failure. Beta-receptors are divided into beta I and beta II. Beta I receptors are mainly found in the heart while beta II receptors are found in the lungs and blood vessels. Stimulation of beta I receptors causes an increase in the heart rate and an increase in the force of contraction. Stimulation of beta II receptors causes peripheral and bronchial dilation. Administration of beta-blockers slows the heart rate and reduces oxygen demand.

02 therapy

To ensure safe and effective treatment, oxygen prescriptions should include the flow rate, delivery system, duration and monitoring of treatment. Oxygen can be delivered to treat hypoxaemia (deficiency of oxygen in arterial blood), to decrease the work of breathing or reduce myocardial workload.

Nasal cannulae or nasal prongs are safe and easy to use, disposable, prevent

rebreathing and are comfortable for long periods. Oxygen is delivered through plastic cannulae in the patient’s nostrils. An advantage is that the administration of oxygen can continue while the patient is eating or talking. Nasal cannulae or prongs are less claustrophobic than conventional masks and, as a result, are often well tolerated by patients. It is possible to deliver oxygen percentages of 24-44 per cent at flow rates of 1-6 litres/minute