Hypoxaemia: Difference between revisions
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[https://www.physio-pedia.com/Respiratory_Failure Respiratory failure] is characterised by a reduction in the function of the lungs due to lung disease, skeletal or neuromuscular disorder. | [https://www.physio-pedia.com/Respiratory_Failure Respiratory failure] is characterised by a reduction in the function of the lungs due to lung disease, skeletal or neuromuscular disorder. | ||
It occurs when gas exchange in the lungs is significantly impaired causing a drop in the levels of oxygen in the blood: hypoxaemia or type 1 respiratory failure.<ref>Tulaimat A, Patel A, Wisniewski M, Gueret R. The validity and reliability of the clinical assessment of increased work of breathing in acutely ill patients. | It occurs when gas exchange in the lungs is significantly impaired causing a drop in the levels of oxygen in the blood: hypoxaemia or type 1 respiratory failure.<ref>Tulaimat A, Patel A, Wisniewski M, Gueret R. [https://europepmc.org/article/med/27288621 The validity and reliability of the clinical assessment of increased work of breathing in acutely ill patients.] Journal of critical care. 2016 Aug 1;34:111-5.</ref> | ||
When there is a drop in oxygen and a rise in carbon dioxide levels this is known as: hypercapnia or type 2 respiratory failure. | When there is a drop in oxygen and a rise in carbon dioxide levels this is known as: hypercapnia or type 2 respiratory failure. | ||
Respiratory failure is demonstrated in [https://www.physio-pedia.com/Arterial_Blood_Gases arterial blood gas] (ABG) | Respiratory failure is demonstrated in [https://www.physio-pedia.com/Arterial_Blood_Gases arterial blood gas] (ABG). Type I respiratory failure is defined as PaO2 <8.0kPa with a normal or lowered PaCO2.<ref name=":0" /> | ||
Type 1 respiratory failure is related to respiratory distress, with increased work of breathing and deranged gas exchange.<ref name=":1">Harden B, Cross J, Broad MA. Respiratory physiotherapy: An on-call survival guide. Elsevier Health Sciences; 2009.</ref> It may occur with or without the presence of excessive pulmonary secretions and/or sputum retention, and is not necessarily related to a primary respiratory problem, e.g. neurological problems may be related to respiratory depression, hypoventilation, reduced level of consciousness and inability to protect the airway<ref name=":1" />. Cough depression and risk of aspiration are a serious concern. | |||
=== Classification and Causes of Hypoxaemia === | |||
There are many causes of hypoxaemia, it is often due to respiratory disorders:<ref name=":2" /> | |||
== Classification and Causes of Hypoxaemia == | |||
There are many causes of | |||
{| class="wikitable" | {| class="wikitable" | ||
! | ! | ||
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<ref name=":0" /><ref name=":1" /><ref name=":3" /> | <ref name=":0" /><ref name=":1" /><ref name=":3" /> | ||
== Clinical Signs == | === Clinical Signs === | ||
A patient with acute hypoxaemia will display some or all of the following | A patient with acute hypoxaemia will display some or all of the following symptoms<ref name=":1" /><ref>Colledge NR, Walker BR, Ralston SH, eds. (2010). ''Davidson's principles and practice of medicine'' (21st ed.). Edinburgh: Churchill Livingstone/Elsevier.</ref>; | ||
{| class="wikitable" | |||
!Sign | |||
!Clinical feature | |||
!Observation | |||
|- | |||
|Central cyanosis | |||
Chronic hypoxaemia may be compensated or uncompensated. The compensation may result in the symptoms to be overlooked initially, however, a further disease or stress such as any increase in oxygen demand may finally unmask the existing hypoxemia. <ref>Adde, | |Blue-ish palor, blue lips | ||
|Hypothermic <36.5 degrees C | |||
|- | |||
|Peripheral shut down | |||
|Cool to touch, clammy | |||
|Hypothermic <36.5 degrees C | |||
|- | |||
|Tachypnoea | |||
|Increased respiratory rate | |||
|>20 breaths per min, appears in distress with breathing | |||
|- | |||
|Low O2 | |||
|Low O2 saturations | |||
|<90% | |||
|- | |||
|Accessory muscle use | |||
|Tracheal tug, flared nostrils, bracing through upper limbs | |||
| | |||
|- | |||
|Reduced mental state | |||
|Confused, agitated | |||
| | |||
|} | |||
Chronic hypoxaemia may be compensated or uncompensated. The compensation may result in the symptoms to be overlooked initially, however, a further disease or stress such as any increase in oxygen demand may finally unmask the existing hypoxemia. <ref>Adde FV, Alvarez AE, Barbisan BN, Guimarães BR. [https://www.sciencedirect.com/science/article/pii/S0021755713000041 Recommendations for long-term home oxygen therapy in children and adolescents]. Jornal de pediatria. 2013 Feb;89(1):06-17. </ref> | |||
== Aim of Physiotherapy == | == Aim of Physiotherapy == | ||
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== Common Issues in Hypoxaemia == | == Common Issues in Hypoxaemia == | ||
Unrecognised respiratory failure may lead to; | |||
* respiratory muscle fatigue | |||
* hypoventilation | |||
* sputum retention | |||
* Decreased O2 (hypoxaemia)<ref name=":1" /> | |||
* An acute assessment to establish the underlying cause is imperative as, if respiratory failure is left untreated, it may progress to one or all of the following; | |||
** cardiac arrhytmia | |||
** cerebral hypoxaemia | |||
** respiratory acidosis | |||
** coma | |||
** cardiorespiratory arrest Thus, timely recognition and treatment of respiratory failure is of the utmost importance and a serious part of a patients care.<ref name=":1" /> | |||
==== Bronchopneumonia ==== | ==== Bronchopneumonia ==== | ||
Bronchopneumonia is a form of pneumonia, sometimes referred to as lobar pneumonia, that also causes inflammation in the bronchi. <ref>Blaisdell FW. Pathophysiology of the respiratory distress syndrome. Arch Surg. 1974 Jan 1;108(1):44-9. | Bronchopneumonia is a form of pneumonia, sometimes referred to as lobar pneumonia, that also causes inflammation in the bronchi. <ref>Blaisdell FW. Pathophysiology of the respiratory distress syndrome. Arch Surg. 1974 Jan 1;108(1):44-9. |
Revision as of 16:33, 6 April 2020
Original Editor - Adam Vallely Farrell
Top Contributors - Adam Vallely Farrell, Lucinda hampton, Abbey Wright, Kim Jackson, Rishika Babburu and Chelsea Mclene
Hypoxaemia[edit | edit source]
Introduction[edit | edit source]
Hypoxaemia is an abnormally low amount of oxygen in the blood, specifically arterial blood[1][2]. Hypoxaemia is defined as the inability to maintain the PaO2 above 8kPa (see ABGs for more details).[3]
It can cause hypoxia (low oxygen) in body tissues if unresolved, which can in turn lead to cell death of the peripheral then central tissues. Hypoxia is also known as type 1 respiratory failure.
Type 1 Respiratory Failure[edit | edit source]
Respiratory failure is characterised by a reduction in the function of the lungs due to lung disease, skeletal or neuromuscular disorder.
It occurs when gas exchange in the lungs is significantly impaired causing a drop in the levels of oxygen in the blood: hypoxaemia or type 1 respiratory failure.[4]
When there is a drop in oxygen and a rise in carbon dioxide levels this is known as: hypercapnia or type 2 respiratory failure.
Respiratory failure is demonstrated in arterial blood gas (ABG). Type I respiratory failure is defined as PaO2 <8.0kPa with a normal or lowered PaCO2.[1]
Type 1 respiratory failure is related to respiratory distress, with increased work of breathing and deranged gas exchange.[5] It may occur with or without the presence of excessive pulmonary secretions and/or sputum retention, and is not necessarily related to a primary respiratory problem, e.g. neurological problems may be related to respiratory depression, hypoventilation, reduced level of consciousness and inability to protect the airway[5]. Cough depression and risk of aspiration are a serious concern.
Classification and Causes of Hypoxaemia[edit | edit source]
There are many causes of hypoxaemia, it is often due to respiratory disorders:[3]
Classification | Cause | |
---|---|---|
Hypoxic hypoxaemia |
|
|
Ischaemic hypoxaemia |
|
|
Anaemic hypoxaemia |
|
|
Toxic hypoxaemia |
|
|
Clinical Signs[edit | edit source]
A patient with acute hypoxaemia will display some or all of the following symptoms[5][6];
Sign | Clinical feature | Observation |
---|---|---|
Central cyanosis | Blue-ish palor, blue lips | Hypothermic <36.5 degrees C |
Peripheral shut down | Cool to touch, clammy | Hypothermic <36.5 degrees C |
Tachypnoea | Increased respiratory rate | >20 breaths per min, appears in distress with breathing |
Low O2 | Low O2 saturations | <90% |
Accessory muscle use | Tracheal tug, flared nostrils, bracing through upper limbs | |
Reduced mental state | Confused, agitated |
Chronic hypoxaemia may be compensated or uncompensated. The compensation may result in the symptoms to be overlooked initially, however, a further disease or stress such as any increase in oxygen demand may finally unmask the existing hypoxemia. [7]
Aim of Physiotherapy[edit | edit source]
The overall aim of physiotherapy is to identify and treat, if appropriate, the cause of the hypoxaemia, thus aiming to increase PaO2 >8kPa while administering appropriate oxygen therapy. [5]
Treatment of Hypoxaemia[edit | edit source]
The primary treatment for hypoxaemia is controlled oxygen therapy, alongside the identification and treatment of the underlying cause. Patients who are unable to maintain a SaO2 >90% with a face mask may require additional respiratory support. This might include either continuous positive airway pressure (CPAP) or intubation and mechanical ventilation. Patients presenting with a unilateral lung disease can be positioned in side-lying, with the unaffected lung down, to try to improve V/Q matching.[5]
Controlled Oxygen Therapy[edit | edit source]
Controlled oxygen therapy is prescribed for hypoxaemic patients to increase alveolar oxygen tension and decrease their work of breathing.[8] It is important to remember that oxygen is a drug and should always be prescribed with the required percentage and/or flow rate. It is usually delivered at 24-60% and can be given by an oxygen mask. Lower requirements of 2-4L/min are commonly supplied via nasal cannulae; however, often a mask may be preferable if hypoxic and/or the patient is a mouth breather.[5] If a patient is requiring over 60% oxygen with persistently low oxygen saturation (<90%) a non-rebreather mask should be used to administer constant flow of high concentration oxygen. CPAP is also useful with profound hypoxaemia once a pneumothorax has been excluded.[9]
Humidification[edit | edit source]
Oxygen therapy is known to dry out the airways. Humidifying oxygen is often used in an attempt to help prevent the drying of the upper respiratory tract. The BTS oxygen guidelines (2008) state that humidification is not required for the delivery of low flow oxygen (4L/minute and under) or short term use of high flow oxygen for short periods.[10] In patients who are requiring high flow oxygen or oxygen for longer periods consider cold or heated humidification. Heated humidification is believed to be better for tenacious secretions or severe bronchospasm. [5]
Treat the cause, e.g. bronchospasm, sputum retention, volume loss[edit | edit source]
Whilst the delivery of oxygen therapy is the primary treatment for hypoxaemia it is essential to treat the cause. If it is a primary respiratory problem, treat this. If the primary problem is cardiac or renal in origin, discuss this with the medical team to help resolve the presenting issue.[5]
Increased work of breathing[edit | edit source]
Patients will commonly present with an increased work of breathing. Positioning is essential to reduce breathlessness and improve ventilation perfusion matching[5]. Airway clearance techniques can also be useful if needed. IPPB may be considered (with a high flow rate) to rest the respiratory muscles and improve efficacy of other treatments.
Common Issues in Hypoxaemia[edit | edit source]
Unrecognised respiratory failure may lead to;
- respiratory muscle fatigue
- hypoventilation
- sputum retention
- Decreased O2 (hypoxaemia)[5]
- An acute assessment to establish the underlying cause is imperative as, if respiratory failure is left untreated, it may progress to one or all of the following;
- cardiac arrhytmia
- cerebral hypoxaemia
- respiratory acidosis
- coma
- cardiorespiratory arrest Thus, timely recognition and treatment of respiratory failure is of the utmost importance and a serious part of a patients care.[5]
Bronchopneumonia[edit | edit source]
Bronchopneumonia is a form of pneumonia, sometimes referred to as lobar pneumonia, that also causes inflammation in the bronchi. [11] A patient presenting with bronchopneumonia will present with troubled breathing due to airway constriction. Due to inflammation, their lungs are not adequately ventilated. Symptoms can range from mild to severe. Physiotherapy treatment can include;
- Ensure medication is optimised (oxygen, analgesia, bronchodilators, antibiotics, etc.)
- Positioning to decrease work of breathing
- Airway clearance techniques
- Humidification[5]
Acute lobar pneumonia[edit | edit source]
Lobar pneumonia is an acute exudative inflammation of an entire pulmonary lobe, produced in 95% of cases by Streptococcus pneumoniae (pneumococci). If not treated lobar pneumonia progresses in 4 stages; namely consolidation, red hepatization, grey hepatization and resolution.[12] Treatment is dependent on the severity of symptoms and may include some of the following techniques;
- During the unproductive phase advice on positioning may reduce WOB
- CPAP is useful for hypoxaemia
- Sputum clearance s only indicated if the patient becomes productive
Pulmonary embolus[edit | edit source]
Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism).[13] Symptoms of a PE may include shortness of breath, chest pain particularly upon breathing in, and coughing up blood. Physiotherapy is not indicated. CPAP may help with severe hypoxaemia.
Pulmonary fibrosis[edit | edit source]
Pulmonary fibrosis describes a collection of diseases which lead to interstitial lung damage and ultimately fibrosis and loss of the elasticity of the lungs. It is a chronic condition characterised by shortness of breath.[14] The lung tissue becomes thickened, stiff and scarred over a period of time. The development of scar tissue is called fibrosis. As the lung tissue becomes scarred and thicker, the lungs start to lose their ability to transfer oxygen into the bloodstream. Treatment of pulmonary fibrosis may involve;
- Present with profound hypoxaemia. Humidified CPAP is effective
- Ensure sufficient oxygen is available when CPAP removed
Pulmonary oedema[edit | edit source]
Pulmonary oedema occurs when fluid accumulates in the alveoli of the lungs causing an increased work of breathing. This fluid accumulation interferes with gas exchange and can cause respiratory failure.[15] Treating a patient with pulmonary oedema may include;
- CPAP is effective in the treatment of pulmonary oedema
- If hypotensive, check that BP does not drop with increased intrathoracic pressure.
- NIV (pressure support with EPAP) may be useful in the patient tiring on CPAP[5]
CO2 retention[edit | edit source]
Uncontrolled oxygen therapy, or receiving too much oxygen, can make people who usually have higher CO2 levels retain more until it reaches dangerous levels.
- Acute CO2 retention is not a reason to reduce FiO2 unless patients have evidence of acute-on-chronic CO2 retention secondary to chronic respiratory disease
- This can be diagnosed by interpretation of recent blood gas results, assessing pH, in relation to PaCO2, standard bicarbonate and base excess. Only this group of patients require judicious oxygen administration )24-28%), which should be prescribed accordingly
Fatigue[edit | edit source]
- Hypoxaemic patients may start to fatigue. This is seen by a rising PaCO2 - type II respiratory failure failure. An important clinical sign requiring immediate attention
Chronic chest patients[edit | edit source]
- Patients who have longstanding chest diseases may have a regular chest clearing routine they adhere to e.g. Bronchiectatic, CF patient
- It is important to discuss this and mould your treatment plan so that it fits within their existing regimen and their current physiotherapy problems[5]
Renal failure[edit | edit source]
- Patient in renal failure may present with an increased work of breathing
- ABGs will show metabolic acidosis, generally with some form of respiratory ompensation e.g. Decreased CO2
- Pulmonary oedema and pleural effusion may also be present[5]
Distended abdomen, e.g. pancreatitis, ascites[edit | edit source]
- Positioning in alternate side-lying or well supported high side-lying is useful
- Standing where possible[5]
References[edit | edit source]
- ↑ 1.0 1.1 1.2 Pollak, Charles P.; Thorpy, Michael J.; Yager, Jan (2010). The encyclopedia of sleep and sleep disorders (3rd ed.). New York, NY. p. 104.
- ↑ 2.0 2.1 Eckman, Margaret (2010). Professional guide to pathophysiology (3rd ed.). Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins. p. 208.
- ↑ 3.0 3.1 Martin, Lawrence (1999). All you really need to know to interpret arterial blood gases (2nd ed.). Philadelphia: Lippincott Williams & Wilkins.
- ↑ Tulaimat A, Patel A, Wisniewski M, Gueret R. The validity and reliability of the clinical assessment of increased work of breathing in acutely ill patients. Journal of critical care. 2016 Aug 1;34:111-5.
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 5.11 5.12 5.13 5.14 5.15 5.16 Harden B, Cross J, Broad MA. Respiratory physiotherapy: An on-call survival guide. Elsevier Health Sciences; 2009.
- ↑ Colledge NR, Walker BR, Ralston SH, eds. (2010). Davidson's principles and practice of medicine (21st ed.). Edinburgh: Churchill Livingstone/Elsevier.
- ↑ Adde FV, Alvarez AE, Barbisan BN, Guimarães BR. Recommendations for long-term home oxygen therapy in children and adolescents. Jornal de pediatria. 2013 Feb;89(1):06-17.
- ↑ Hardinge M, Annandale J, Bourne S, Cooper B, Evans A, Freeman D, Green A, Hippolyte S, Knowles V, MacNee W, McDonnell L. British Thoracic Society guidelines for home oxygen use in adults: accredited by NICE. Thorax. 2015 Jun 1;70(Suppl 1):i1-43.
- ↑ Machado ML, Vollmer WM, Togeiro SM, Bilderback AL, Oliveira MC, Leitão FS, Queiroga F, Lorenzi-Filho G, Krishnan JA. CPAP and survival in moderate-to-severe obstructive sleep apnoea syndrome and hypoxaemic COPD. European Respiratory Journal. 2010 Jan 1;35(1):132-7.
- ↑ O’driscoll BR, Howard LS, Davison AG. BTS guideline for emergency oxygen use in adult patients. Thorax. 2008 Oct 1;63(Suppl 6):vi1-68.
- ↑ Blaisdell FW. Pathophysiology of the respiratory distress syndrome. Arch Surg. 1974 Jan 1;108(1):44-9.
- ↑ Pneumonia. (2018, January 9). Physiopedia, . Retrieved 11:29, March 31, 2018 from https://www.physio-pedia.com/index.php?title=Pneumonia&oldid=182184.
- ↑ Dalen JE, Alpert JS. Natural history of pulmonary embolism. Progress in cardiovascular diseases. 1975 Jan 1;17(4):259-70.
- ↑ Gribbin J, Hubbard RB, Le Jeune I, Smith CJ, West J, Tata LJ. Incidence and mortality of idiopathic pulmonary fibrosis and sarcoidosis in the UK. Thorax. 2006 Nov 1;61(11):980-5.
- ↑ Masip J, Betbesé AJ, Páez J, Vecilla F, Cañizares R, Padró J, Paz MA, de Otero J, Ballús J. Non-invasive pressure support ventilation versus conventional oxygen therapy in acute cardiogenic pulmonary oedema: a randomised trial. The Lancet. 2000 Dec 23;356(9248):2126-32.