Safe and effective use of supplemental oxygen therapy

Transcription

1 PEER-REVIEWED ardiorespiratory / CPD evidene & pratie Why you should read this artile: To ensure your knowledge of the ommon indiations and ontraindiations for supplemental oxygen therapy is up to date To understand the proess of determining if patients have a linial need for supplemental oxygen therapy and evaluating the effets of the intervention To ount towards revalidation as part of your 35 hours of CPD, or you may wish to write a refletive aount (UK readers) To ontribute towards your professional development and loal registration renewal requirements (non-uk readers) Safe and effetive use of supplemental oxygen therapy Elizabeth Allibone, Tania Soares and Alexandra Wilson Citation Allibone E, Soares T, Wilson A (2018) Safe and effetive use of Nursing Standard. doi: / ns.2018.e11227 Peer review This artile has been subjet to external double-blind peer review and heked for plagiarism using automated software Correspondene e.allibone@rbht.nhs.uk \@LizAllibone Conflit of interest None delared Abstrat Nurses have an important role in early identifiation of fators that an ompromise oxygen delivery to the lungs and tissues in the body, and in ensuring that patients who may require supplemental oxygen therapy are assessed and managed safely and ompetently. This artile provides an overview of the anatomy and physiology in relation to oxygen delivery to the lungs and tissues in the body, and outlines the ommon indiations and ontraindiations for It also disusses the approahes that nurses an adopt to assess a patient s linial need for supplemental oxygen therapy, as well as the safety onsiderations required. Author details Elizabeth Allibone, head of linial eduation and training, Nursing Development and Eduation, Royal Brompton and Harefield NHS Foundation Trust, London, England; Tania Soares, sister, Nursing Development and Eduation, Royal Brompton and Harefield NHS Foundation Trust, London, England; Alexandra Wilson, sister linial eduation, Nursing Development and Eduation, Royal Brompton and Harefield NHS Foundation Trust, London, England Keywords breathlessness, linial skills, ritial are, diagnosis, emergeny are, observations, oxygen therapy, patient assessment, patients, respiratory Aepted 12 June 2018 Published online July 2018 Permission To reuse this artile or for information about reprints and permissions, ontat permissions@rni.om Aims and intended learning outomes This artile aims to provide information regarding the safe and effetive use of supplemental oxygen therapy. After reading this artile and ompleting the time out ativities you should be able to: Desribe the anatomy and physiology in relation to oxygen delivery to the lungs and tissues in the body. Identify the ommon indiations and ontraindiations for supplemental oxygen therapy. Disuss the monitoring of oxygen saturations and the fators that an affet pulse oximetry readings. Outline a systemati approah to patient assessment to establish a linial need for Understand the safety onsiderations for This artile should be read alongside loal poliies and proedures and any national guidelines, suh as those from the British Thorai Soiety (O Drisoll et al 2017) or the Thorai Soiety of Australia and New Zealand (Beasley et al 2015). Sine supplemental oxygen is a mediine and a medial gas, nurses involved in its use must be trained in its administration. Introdution Oxygen is essential for life. Effiient oxygen delivery to the lungs and tissues in the body is essential in health and in patients who are autely unwell. These patients have an inreased rate of metaboli ativity or stress, and the body will attempt to manage the risis and maintain homeostasis. This leads to an inrease in the amount of oxygen required for aerobi metabolism (the proess by whih food substanes suh as fats and arbohydrates are broken down in the presene of oxygen to produe energy) and tissue survival (Margereson and Withey 2012). Oxygen delivery depends on adequate ventilation and gas exhange, and effetive irulatory distribution. Without oxygen, ells die, and the body systems they support fail (Woodrow 2016). Oxygen reserve nursingstandard.om RCN Publishing Company Limited 2018

2 ardiorespiratory / CPD evidene & pratie PEER-REVIEWED in the tissues and lungs is minimal. Without suffiient oxygen delivery, tissue hypoxia may our within four minutes (Ward et al 2015). However, tolerane to hypoxia differs in health and disease and organs and ells also vary signifiantly in their sensitivity to hypoxia (Leah and Treaher 2002). Box 1 provides definitions of terms related to oxygenation and respiratory failure, and Box 2 outlines ommon indiations for Supplemental oxygen therapy is reommended for all patients who are autely hypoxaemi and for many patients who are at risk of hypoxaemia. While onsidered a life-saving intervention, as a medial treatment, initial and ongoing assessment and evaluation is vital to ensure its use is safe and effetive, beause oxygen therapy an be detrimental to a patient s health (Olive 2016). Furthermore, pratie gaps exist among some nurses, suh as lak of knowledge of orret oxygen presribing or of oxygen delivery devies, whih may lead to patients being harmed unintentionally (Cousins et al 2016). However, while oxygen is a treatment for hypoxia, it has no therapeuti value to a person with shortness of breath who has adequate levels of oxygen (Beasley et al 2015, O Drisoll et al 2017). Supplemental oxygen therapy also does not treat the underlying auses of hypoxaemia. Nurses have a responsibility to ensure that oxygenation is optimised at pulmonary and ellular level as part of their duty of are to patients. This requires knowledge of respiratory and ardia physiology, as well as seletion of the appropriate equipment and delivery method for Ongoing assessment and evaluation of patients is required to ensure that the treatment is safe and effetive, preventing further deterioration and a medial emergeny. Box 3 lists the signs of deteriorating respiratory funtion. Failure to administer oxygen appropriately an result in serious harm to the patient (Ridler et al 2014, O Drisoll et al 2017). Box 4 shows the linial hazards and risks assoiated with supplemental oxygen therapy and hyperoxaemia. Exessive oxygen administration in some patients who are at risk of hyperapnia, for example those with hroni obstrutive pulmonary disease (COPD), morbid obesity or ysti fibrosis, may result in respiratory failure and possibly death (Austin et al 2010, Bourke and Burns 2015, Cousins et al 2016). TIME OUT 1 Identify the ommon indiations for supplemental oxygen therapy in patients you have ared for. What parameters were set to guide its use, suh as target oxygen saturation ranges? If these vary between patients, an you onsider why? Supplemental oxygen presription and target oxygen saturation ranges It is reommended that supplemental oxygen is regarded as a presriptiononly drug, whih requires BOX 1. Definitions of terms related to oxygenation and respiratory failure Hypoxaemia low partial pressure of oxygen in the blood (PaO 2 ). Hypoxaemia an also be measured in relation to oxyhaemoglobin saturation or oxygen saturation within the arterial blood (SaO 2 ). It ours when PaO 2 is 8kPa or SaO 2 is 90% Hypoxia ours when oxygen supplies are insuffiient to meet oxygen demands in a partiular ompartment, for example alveolar or tissue hypoxia. Supplemental oxygen therapy an only orret hypoxia resulting from hypoxaemia Hyperapnia ours when partial pressure of arbon dioxide (PaCO 2 ) is above the normal range of kPa. Patients with hyperapnia are onsidered to have type II respiratory failure, even if their oxygen saturation is within the normal range Type I respiratory failure hypoxaemia in the absene of hyperapnia Type II respiratory failure hypoxaemia with hyperapnia Hyperoxaemia high PaO 2 in the blood, of >16kPa. The SaO 2 will not hange from 100% Hyperoxia high oxygen ontent to the tissues and organs. The lung is designed to manage onentrations of 21% of oxygen; when given in higher onentrations this may result in oxygen toxiity. A high onentration of oxygen an result in ellular injury through inreased prodution of reative oxygen speies and free radials, whih an interfere with the funtion of intraellular maromoleules, resulting in ell death (Ridler et al 2014, Stay 2014, Bourke and Burns 2015, Marieb and Hoehn 2015, O Drisoll et al 2017) BOX 2. Common indiations for supplemental oxygen therapy Critial illnesses requiring high levels of supplemental oxygen therapy Cardia arrest or resusitation Shok Sepsis Major trauma Major pulmonary haemorrhage Major head injury Drowning Anaphylaxis Carbon monoxide poisoning Serious illnesses requiring moderate levels of supplemental oxygen therapy if the patient is hypoxaemi Aute hypoxaemia with the ause not yet diagnosed Aute asthma Pneumonia Aute breathlessness as a result of lung aner Deterioration of lung fibrosis or other interstitial lung disease Pneumothorax (ollapsed lung) Pleural effusions Pulmonary embolism Aute heart failure Severe anaemia Post-operative breathlessness (Adapted from O Drisoll et al 2017) a presription in all but emergeny situations (Beasley et al 2015, Cousins et al 2016, Olive 2016, O Drisoll et al 2017). A target oxygen saturation range should be inluded in the presription, whih aims to ahieve a speified outome, rather than speifying the oxygen delivery method alone. In patients who are not at risk of type II (hyperapni) respiratory failure, the reommendations for target oxygen saturation ranges vary between professional bodies worldwide (Cousins at al 2016). For example, the British Thorai Soiety (O Drisoll et al 2017) guidelines reommend that oxygen should be presribed to ahieve a target oxygen saturation of 94-98% for most patients who are autely unwell. However, in Australia and New Zealand the target oxygen saturation range is lower, at 92-96%. The rationale for this lower target is that it aims to redue exessive use of highonentration oxygen therapy, with the upper level of 96% aiming to avoid the risk of hyperoxia. The RCN Publishing Company Limited 2018 nursingstandard.om

3 PEER-REVIEWED BOX 3. Signs of deteriorating respiratory funtion Inreased respiratory rate Dereased oxygen saturation Drowsiness Headahe Faial flushing Tremor Elevated trak-and-trigger system sore, for example National Early Warning Sore 2 Inreased need for supplemental oxygen therapy to maintain target oxygen saturation range Carbon dioxide retention, as indiated via arterial blood gas measurement Sweating Posture, for example if the patient is leaning forward and gasping for air Restlessness and onfusion Distress Inability to speak in full sentenes Use of aessory musles for inspiration or expiration (O Drisoll et al 2017, Welh and Blak 2017) target range for those at risk of type II (hyperapni) respiratory failure is 88-92% or should be patient-speifi (Beasley et al 2015, O Drisoll et al 2017). It is reommended that the healthare setting should have a standard oxygen presription doument or a speifi oxygen setion on the paper or eletroni system (O Drisoll et al 2017). The presription should inlude the indiation, mode of delivery, amount, and monitoring parameters, for example the target oxygen saturation range or arterial blood gas measurements, with the drug hart signed by the nurse aordingly. The presription should stipulate the initial starting dose, inluding the delivery devie and flow rate. If supplemental oxygen therapy is administered immediately without a presription in an emergeny, this intervention should be reorded afterwards in a similar way to the reording of all other emergeny treatment (O Drisoll et al 2017). Nurses must always adhere to the requirements in their linial area. In patients not at risk of type II (hyperapni) respiratory failure with oxygen saturations of less than 85%, oxygen should be immediately initiated via a reservoir mask at 15 litres per minute (L/min) (Beasley et al 2015, O Drisoll et al 2017). Arterial blood gas measurements, ontinuous monitoring of vital signs, inluding SpO 2, and presription of the appropriate target oxygen saturation range, will be required one the patient has stabilised (Perkins et al 2015). When the patient has stabilised, the oxygen onentration an be adjusted downwards using a nasal annula or simple fae mask to maintain a target oxygen saturation of 94-98% (O Drisoll et al 2017). In serious illness with hypoxaemia but low risk of type II (hyperapni) respiratory failure, oxygen therapy an be initiated via a nasal annula at 2-6L/min or a simple fae mask at 5-10L/min (Beasley et al 2015, O Drisoll et al 2017). The patient must be monitored losely for signs of deterioration beause they might require transfer to a ritial are unit. The nurse should seek assistane from ritial are speialists or other healthare pratitioners, where neessary. Anatomy and physiology of respiration It is important for nurses to have knowledge of the relevant anatomy, physiology and biohemistry of respiration and gas exhange, to enable them to understand the rationale and limitations of Respiration has four phases: Key points Nurses have a responsibility to ensure that oxygenation is optimised at pulmonary and ellular level as part of their duty of are Supplemental oxygen therapy is reommended for all patients who are autely hypoxaemi and for many patients who are at risk of hypoxaemia. While onsidered a life-saving intervention, as a medial treatment, initial and ongoing assessment and evaluation is vital to ensure its use is safe and effetive Exessive oxygen administration in some patients who are at risk of hyperapnia, for example those with hroni obstrutive pulmonary disease, morbid obesity or ysti fibrosis, may result in respiratory failure and possibly death (Austin et al 2010, Bourke and Burns 2015, Cousins et al 2016) It is reommended that supplemental oxygen is regarded as a presription-only drug, whih requires a presription in all but emergeny situations (Beasley et al 2015, Cousins et al 2016, Olive 2016, O Drisoll et al 2017). A target oxygen saturation range should be inluded in the presription BOX 4. Clinial hazards and risks assoiated with supplemental oxygen therapy and hyperoxaemia Clinial hazards assoiated with the pratial aspets of supplemental oxygen therapy Combustion and potentially dangerous when in ontat with soures of ignition and flammable material Inability of healthare pratitioners to set flow orretly on oxygen ylinders Inorret use of valve, for example if it is not opened orretly, ausing failure to obtain or maintain oxygen flow Inorret seletion of ylinder, for example using the inorret gas or ylinder size Unsafe storage, for example in areas whih are not seure, inadequately ventilated or at risk of extremes of temperature Risks assoiated with supplemental oxygen therapy and hyperoxaemia Loss of hypoxi drive Oxygen toxiity and alveolar damage Coronary and erebral vasoonstrition Redued ardia output Delay in reognition of linial deterioration Potentially harmful for patients with mild or moderate stroke Supplemental oxygen therapy an be harmful in some types of poisoning, for example paraquat (a type of pestiide) or aid aspiration Rebound hypoxaemia Worsening ventilation-perfusion (V/Q) mismath (Cousins et al 2016, O Drisoll et al 2017) pulmonary ventilation, external respiration, internal respiration, and transport of gases. Pulmonary ventilation Pulmonary ventilation is the mehanism of breathing: inspiration nursingstandard.om RCN Publishing Company Limited 2018

4 ardiorespiratory / CPD evidene & pratie PEER-REVIEWED and expiration. Air flows in and out of the lungs as a result of pressure differenes between the atmosphere and the gases inside the lungs (Bourke and Burns 2015, Credland 2017). The work of breathing is the amount of energy required to overome airway resistane and lung ompliane (the lung s ability to streth and expand). Airway resistane is aused by inelasti surfaes, as well as the narrowed diameter of the airways, whih slow down the flow of gases. The tension of the alveoli also influenes pressure, whih prevents the expansion of the alveoli. Pulmonary surfatant redues the surfae tension so that the alveoli do not ollapse during expiration. Lung ompliane is also important in gas flow. The more the lungs an streth, the greater the potential volume of the lungs. The greater the volume of the lungs, the lower the air pressure within the lungs (Bourke and Burns 2015, Marieb and Hoehn 2015). Any interferene with these ations may impair normal ventilation and effetive oxygenation. Pulmonary diseases are ategorised as obstrutive or restritive, depending on how the underlying ause affets normal ventilation. Asthma, bronhitis and COPD are ommon onditions where airway resistane and lung ompliane have to be overome, inreasing the work of breathing so muh that one third or more of the total body energy is used for ventilation (Bourke and Burns 2015, Marieb and Hoehn 2015, Credland 2017). Therefore, in addition to supplemental oxygen therapy, the patient s underlying ondition may also require treatment. For example, in aute asthma, where there is airway inflammation and smooth musle ontration resulting in airway obstrution, the wall of the airway beomes thikened by oedema. In severe ases, this an lead to fibrosis of the wall and fixed narrowing of the airway (Bourke and Burns 2015). A bronhodilator and anti-inflammatory drugs may be required in addition to oxygen therapy in these ases, or some form of respiratory support. Sputum learane tehniques suh as the ative yle of breathing tehnique or osillating positive expiratory pressure therapy may also be required (Bourke and Burns 2015). External respiration External respiration is the exhange of oxygen and arbon dioxide between the alveoli and pulmonary apillary blood aross the respiratory membrane. This is mainly influened by (Marieb and Hoehn 2015, Tortora and Derrikson 2017): Partial pressure gradients and gas solubilities. Thikness and surfae area of the respiratory membrane. Ventilation-perfusion oupling mathing alveolar ventilation with pulmonary blood perfusion. In healthy lungs, the respiratory membrane is thin, allowing effiient gas exhange. An inrease in the thikness of the alveolar-apillary membrane, for example resulting from pulmonary oedema or fibrosis, or a derease in the surfae area of the membrane, for example pneumonetomy, pulmonary embolus or emphysema, dereases the rate of diffusion of oxygen and arbon dioxide. Oxygen therapy may augment the rate of diffusion aross the alveolar apillary membrane by inreasing the onentration gradient (O Drisoll et al 2017). Tumours, muus or inflammation also redue surfae area by bloking gas flow into the alveoli (Stay 2014, Marieb and Hoehn 2015) and therefore may also require treatment to orret or stabilise the underlying ause. External respiration is inreasingly effetive when there is an adequate supply of oxygen and blood. The alveoli must be wellventilated to ensure a suffiient supply of oxygen. Oxygen therapy is only effetive when alveolar apillary units have some funtional ventilation (O Drisoll et al 2017). At the same time, pulmonary blood flow must be suffiient for gas exhange to our. This perfet math between ventilation and perfusion is known as the ventilation-perfusion (V/Q) ratio. Disruptions to the pulmonary blood flow or ventilation is known as a V/Q mismath. The V/Q ratio is signifiantly affeted by hypoxia. Low oxygen levels in one area of the lung have a diret vasoonstritor effet on the pulmonary artery supplying that area. This has the benefiial effet of diverting blood away from the area of the lung that is inadequately ventilated towards the area that is well ventilated, maintaining effiient gas exhange (hypoxi pulmonary vasoonstrition) (Bourke and Burns 2015, O Drisoll et al 2017). However, in severe pneumonia, this may not be effetive and supplemental oxygen therapy is reommended (O Drisoll et al 2017), alongside antibiotis and other interventions. Appropriate positioning of the patient is vital to maximise ventilation. Where possible, the patient should ideally be assisted into an upright position, supported with pillows. An upright position may improve oxygenation by enouraging perfusion, thus promoting gas exhange (Margereson and Withey 2012, O Drisoll et al 2017). This alone may orret hypoxaemia, reduing the need for supplemental oxygen therapy. Internal respiration Internal respiration is the gas exhange that ours between the body tissues and the blood. At this level, gas exhange ours by simple diffusion as a result of a partial pressure gradient. The aim of supplemental oxygen therapy is to inrease oxygen delivery to the tissues. Hypoxaemia may be aused by respiratory onditions where there is inadequate oxygenation at the alveolar level, suh as pneumonia or pulmonary embolism, ausing disruptions in gas exhange that subsequently ause tissue hypoxia. This type of hypoxaemia may be treated with oxygen therapy. The administration of supplemental oxygen therapy in other onditions, suh as severe anaemia or insuffiient ardia output, is less effetive; in suh ases it is more important to treat the underlying ondition than to administer oxygen to a patient with low oxygen saturation. The delivery of oxygen to the tissues is intimately related to the adequate flow of oxygenated blood. It is neessary to ensure that suffiient ardia RCN Publishing Company Limited 2018 nursingstandard.om

5 PEER-REVIEWED output is maintained and that patients have adequate irulatory blood volume, venous return and myoardial funtion. In addition, to optimise oxygen delivery from the lungs to the tissues, it is essential to treat onditions that impair delivery of oxygen to the lungs, suh as upper airway obstrutions, bronhoonstrition, seretions or pulmonary oedema (O Drisoll et al 2017). Transport of gases Transport of gases refers to the movement of oxygen and arbon dioxide to and from the tissue ells. For the exhange of oxygen and arbon dioxide to our, both gases must be transported between the external and internal respiration sites. These gases require a speialised transport system for most of the gas moleules to be moved between the lungs and other tissues. Haemoglobin is the main vehile to transport oxygen and arbon dioxide. The patient s oxygen saturations indiate the degree to whih the haemoglobin ontained in the red blood ells has bonded with oxygen moleules. Measuring oxygen saturations The measurement of oxygen saturations via pulse oximetry (SpO 2 ) is onsidered a fundamental vital sign (Beasley et al 2015), and is often referred to as the fifth vital sign (O Drisoll et al 2017). It should be performed in all patients who are breathless and/or autely unwell. Patients reeiving supplemental oxygen therapy should undergo regular SpO 2 monitoring, as determined by the presriber and in aordane with loal and national guidelines. They should have their SpO 2 monitored for at least five minutes after ommening The frequeny of subsequent SpO 2 measurements will depend on the patient s ondition and their stability, as well as the nurse s linial judgement. For example, patients who are ritially ill should have their SpO 2 monitored ontinuously and reorded every few minutes, whereas patients with mild breathlessness may require monitoring hourly or as indiated by a trak-and-trigger system sore suh as the National Early Warning Sore 2 (Royal College of Physiians 2017). Pulse oximetry readings an be affeted by several fators, as outlined in Box 5. For example, in patients with anaemia, oxygen saturation of the available haemoglobin will be normal, even when the amount of haemoglobin in the blood is redued. Therefore, the patient may be hypoxaemi despite having normal oxygen saturations (O Drisoll et al 2017). The presene of arbon monoxide may falsely elevate SpO 2 measurements, sine oxygen is displaed from haemoglobin by arboxyhaemoglobin, but this registers falsely as adequate oxygen saturation. In patients who are autely unwell, an arterial blood gas analysis should be undertaken, whih is onsidered the gold standard in assessing respiratory failure. Arterial blood gas analysis enables a more aurate reading of oxygen saturations within the arterial blood (SaO 2 ) ompared with SpO 2, and also measures the partial pressure of oxygen (PaO 2 ), partial pressure of arbon dioxide (PaCO 2 ), ph or hydrogen level, and, in some devies, haemoglobin and eletrolytes. Arterial blood gas analysis enables diagnosis of respiratory or metaboli aidosis or alkalosis, whih may further guide BOX 5. Fators that an affet pulse oximetry readings Anaemia Critial illness Hypotension Malposition of the pulse oximeter probe Nail varnish or false nails Patient motion Peripheral vasoonstrition Presene of arbon monoxide in the blood, for example resulting from smoke inhalation or ar exhaust fumes Readings beome inaurate one the patient s oxygen saturation drops below 80% Redued ardia output or hypovolaemia Skin pigmentation, for example jaundie Site used to undertake pulse oximetry; the optimal sites are the fingertips or earlobes (Margereson and Withey 2012, Beasley et al 2015, O Drisoll et al 2017, Welh and Blak 2017) the supplemental oxygen therapy required, as well as any additional interventions. TIME OUT 2 While pulse oximetry is a quik and easy way to measure oxygen saturations, there are several fators that an affet the auray of its readings. Using the information in Box 5, an you identity any linial situations where aution would be required in interpreting these readings? Assessing the need for supplemental oxygen therapy Respiratory assessment of a patient enables healthare pratitioners to determine if there is adequate gas exhange, that tissues are effetively oxygenated, and that arbon dioxide is being exreted. Therefore, respiratory assessment is essential in determining if the patient has a linial need for supplemental oxygen therapy and an also assist with evaluating the effets of the intervention. Assessing the patient s external respiration inludes reording their respiratory rate, pattern, depth and effort. Assessing the patient s internal respiration involves examining their skin olour for signs of yanosis, measuring SpO 2, and heking their organ funtion, for example assessing for any neurologial impairment. Where possible, taking the patient s medial and soial history is important in a respiratory assessment (Bourke and Burns 2015) to identify any long-term illnesses or fators affeting their respiratory funtion, suh as smoking. It is also important for the nurse to be aware of any existing oxygen requirements that the patient has, for example home oxygen and/or non-invasive ventilation. Before the nurse begins the assessment, they should identify any speial onsiderations that might be affeting the patient s respiration and breathing, suh as those listed in Box 6. An assessment using the ABCDE (airway, breathing, irulation, disability and exposure) approah and the look, listen and feel approah is reommended (Box 7) (Margereson and Withey 2012, Smith and Rushton 2015, Resusitation Counil (UK) 2016, nursingstandard.om RCN Publishing Company Limited 2018

6 ardiorespiratory / CPD evidene & pratie PEER-REVIEWED Welh and Blak 2017). The following setions outline some of the important aspets of using the ABCDE approah to assess an adult patient with breathing diffiulties in an aute setting. Airway To inspire oxygen, independently or with assistane, the patient s airway must be patent. In an individual who is onsious, the simplest way to assess airway pateny is by talking to them. However, if the patient is unonsious or unable to maintain their airway, it is ruial to open their airway using the headtilt hin-lift manoeuvre unless the patient has, or is suspeted of having, a ervial spine injury and summon immediate assistane. BOX 6. Speial onsiderations that might affet a patient s respiration and breathing Pregnany hanges in oestrogen and progesterone ause fluid retention and affet respiratory funtion. In the third trimester, the diaphragm may beome displaed, thereby affeting lung expansion Obesity lung expansion ould be affeted by suboptimal positioning, for example lying supine Cirulatory issues heart failure, pulmonary oedema and anaemia may inhibit effetive gas exhange Environment fators suh as room temperature may influene assessment, for example a old environment might ause shivering. The environment in whih the assessment takes plae ould also inrease the patient s anxiety and ause hanges in their breathing, for example if it is noisy or busy Trauma partiularly hest trauma. If the patient is experiening pain, they may find it hallenging to take deep breaths. A pneumothorax (ollapsed lung) may be present and therefore thorough assessment is required Known allergies if an allergy auses anaphylaxis, the patient s airway may swell, ausing breathing diffiulties Abdominal distention for example aused by asites or bowel obstrution. This may prevent full inflation of the lungs (Adapted from Moore 2009) BOX 7. Look, listen and feel approah LOOK: Inside the mouth for vomit, seretions and foreign bodies At the hest and abdominal movement for signs of air entry to both lungs LISTEN: Gurgling might indiate the presene of a liquid or semi-solid foreign body Wheeze might indiate obstrution of upper or lower airways Stridor might indiate obstrution or laryngeal spasm Snoring might indiate the pharynx is oluded FEEL: For airflow at the mouth and nose The hest for air entry (Adapted from Resusitation Counil (UK) 2016) If any airway obstrution is identified, this must be addressed without delay before ontinuing with the assessment. In addition to oxygen therapy, the patient may require bronhodilators or oropharyngeal sutioning to lear the airway (O Drisoll et al 2017). Breathing If the work of breathing is inadequate to ahieve effetive ventilation, this is onsidered a medial emergeny. In suh ases, medial staff must be alerted and oxygen must be delivered using a bag-valve-mask to ensure the patient is adequately oxygenated. The nurse should also assess the patient s SpO 2, use of aessory musles in the nek and hest indiating inreased respiratory effort, and the patient s position, for example if they are leaning forward and gasping for air this may indiate that the patient feels short of breath. The patient s respiratory rate should also be assessed for one full minute to ensure an aurate measurement. It is important to note that a patient s breathing may hange if they are aware that it is being monitored. It is suggested that the patient s pulse should be palpated for two minutes, ounting their pulse rate for the first minute and their respiratory rate for the seond minute (Dougherty and Lister 2015). Symmetry of hest movement should also be assessed to hek that both lungs are adequately ventilating. The normal respiratory rate is breaths per minute in adults. Assessing the patient s respiratory rate and patterns an assist with diagnosing a range of onditions that are not always respiratory in nature, although might require The use of oxygen therapy an redue breathlessness in patients who are hypoxaemi; however, it has not been proven that it onsistently relieves breathlessness in patients who are non-hypoxaemi (Beasley et al 2015, O Drisoll et al 2017). Use of a handheld fan or opening a window may be onsidered to relieve breathlessness. The patient may experiene anxiety beause they feel short of breath, whih may itself lead to shallow breaths and hypoxia, requiring supplemental oxygen until their anxiety is redued. Appropriately trained healthare pratitioners should undertake ausultation to assess for abnormal breath sounds, suh as: rakles, whih might indiate pneumonia or pulmonary oedema; wheezing, whih might indiate obstrution or lung disease, for example asthma; and redued sounds, whih might indiate ateletasis, pleural effusions or other issues that may affet gas exhange (Bourke and Burns 2015, Welh and Blak 2017). A hest X-ray may also be benefiial in diagnosing any hanges to respiratory funtion, whih must be reviewed by a healthare pratitioner who is ompetent in performing this task. Palpating the patient s hest and abdomen may identify fators influening respiratory funtion, suh as equal rise and fall of the hest, abdominal distension, hest seretions and depth of inspiration. Colleting a sputum sample ould assist with diagnosing the underlying ause of the patient requiring supplemental oxygen therapy, for example if an infetion is present. Cirulation Cirulation may be affeted by hanges to respiratory funtion, venous return, ventriular filling and heart rate. Therefore, it is important to omplete a full set of observations, inluding heart rate, blood pressure and temperature. The patient s apillary refill time may also be assessed, and, in ritial are or high dependeny units, entral venous pressure may be monitored if the patient has a entral venous atheter in plae. With inreased work of breathing, the heart rate an inrease signifiantly as a ompensatory mehanism, whih may affet the ardia output. However, profound hypoxaemia may ause bradyardia and arrhythmias. In respiratory deterioration there may also be hypotension with haemodynami instability, so the patient s blood pressure should also be monitored (Margereson and Withey 2012). Disability The patient s level of onsiousness RCN Publishing Company Limited 2018 nursingstandard.om

7 PEER-REVIEWED should be assessed beause neurologial signs of onfusion, drowsiness and weakness may be indiators of hypoxaemia or hyperapnia (Welh and Blak 2017). The nurse should hek whether the patient has a hearing impairment, if there is a language barrier or if they do not understand what is being asked, rather than assuming they are onfused. The nurse should also be aware that any signs of distress and agitation that the patient is exhibiting may be as a result of fear and anxiety, and not hypoxaemia. Exposure Assessing the patient s skin pallor an be a useful indiator of hypoxaemia, although yanosis is a late sign of respiratory dysfuntion. Peripheral yanosis is reognised as a blueish olour of the skin and muous membranes resulting from hypoxaemia and may be visible at the patient s nail beds, earlobes or fingertips. However, peripheral yanosis alone is an unreliable sign of hypoxaemia beause it an be present in other onditions, suh as polyythaemia (Baernstein et al 2008, Margereson and Withey 2012). Central yanosis an present as blue lips and bual muosa and may be observed when more than 5g/dL of haemoglobin is unsaturated or the patient s SpO 2 is below 85% (Bourke and Burns 2015, Welh and Blak 2017). However, patients with severe anaemia might not exhibit entral yanosis even if they are severely hypoxi (Bourke and Burns 2015, Welh and Blak 2017). TIME OUT 3 Consider the ABCDE approah to patient assessment. How might respiratory funtion affet eah aspet? Disuss with a olleague Patient safety onsiderations Nurses who are involved in administering and titrating supplemental oxygen must be trained to use the equipment safely, following loal poliies, guidelines and safety legislation, whih may be inluded as part of medial gas training. The nurse should also be able to selet the appropriate equipment for administering supplemental oxygen based on knowledge of its risks and benefits, assess the suitability of the oxygen delivery devies for individual patients, and reognise the need for alterations in oxygen therapy or medial review. It is also important for nurses to onsult loal poliies and proedures, as well as national devies safety updates, suh as those from the Mediines and Healthare produts Regulatory Ageny in the UK ( organisations/mediines-andhealthare-produts-regulatoryageny) or the Therapeuti Goods Administration in Australia (www. tga.gov.au). Conlusion Nurses have an important role in the use of supplemental oxygen therapy in aute settings, inluding assessing patients who might require this treatment. Therefore, they should have an understanding of the theoretial, pratial and evidene-based priniples of oxygen administration and titration, as well as the neessary safety onsiderations. This will enable them to reognise and redue potential hazards and ompliations, and to ensure that the patient are they provide is safe and effetive. TIME OUT 4 Consider how ensuring the safe and effetive use of supplemental oxygen therapy relates to The Code: Professional Standards of Pratie and Behaviour for Nurses and Midwives (Nursing and Midwifery Counil 2015) or, for non-uk readers, the requirements of your regulatory body TIME OUT 5 Now that you have ompleted the artile, reflet on your pratie in this area and onsider writing a refletive aount: rni.om/refletive-aount Referenes Austin MA, Wills KE, Blizzard L et al (2010) Effet of high flow oxygen on mortality in hroni obstrutive pulmonary disease patients in prehospital setting: randomised ontrolled trial. BMJ. 341, doi: /bmj Baernstein A, Smith KM, Elmore JG (2008) Singing the blues: is it really yanosis? Respiratory Care. 53, 8, Beasley R, Chien J, Douglas J et al (2015) Thorai Soiety of Australia and New Zealand oxygen guidelines for aute oxygen use in adults: swimming between the flags. Respirology. 20, 8, doi: /resp Bourke SJ, Burns GP (2015) Respiratory Mediine: Leture Notes. Ninth edition. Wiley Blakwell, Oxford. Cousins JL, Wark PAB, MDonald VM (2016) Aute oxygen therapy: a review of presribing and delivery praties. International Journal of Chroni Obstrutive Pulmonary Disease. 11, 1, doi: /COPD. S Credland N (2017) Respiratory anatomy and physiology. In Gibson V, Waters D (Eds) Respiratory Care. CRC Press, Boa Raton FL, Dougherty L, Lister S (Eds) (2015) The Royal Marsden Manual of Clinial Nursing Proedures. Ninth edition. Wiley-Blakwell, Oxford. Leah RM, Treaher DF (2002) The pulmonary physiian in ritial are 2: oxygen delivery and onsumption in the ritially ill. Thorax. 57, doi: /thorax Margereson C, Withey S (2012) The patient with aute respiratory problems. In Peate I, Dutton H (Eds) Aute Nursing Care: Reognising and Responding to Medial Emergenies. Taylor and Franis, Oxford, Marieb EN, Hoehn K (2015) Human Anatomy and Physiology. Tenth edition. Pearson, San Franiso CA. Moore T (2009) Oxygen therapy. In Woodrow P, Moore T (Eds) High Dependeny Nursing Care: Observation, Intervention and Support for Level 2 Patients. Seond edition. Routledge, London, Nursing and Midwifery Counil (2015) The Code: Professional Standards of Pratie and Behaviour for Nurses and Midwives. NMC, London. O Drisoll BR, Howard LS, Earis J et al (2017) BTS guideline for oxygen use in adults in healthare and emergeny settings. Thorax. 72, Suppl 1, ii1-ii90. doi: /thoraxjnl Olive S (2016) Pratial proedures: oxygen therapy. Nursing Times. 112, 1-2, Perkins G, Colquhoun M, Deakin C et al (2015) Adult Basi Life Support and Automated External Defibrillation. (Last aessed: 10 July 2018.) Resusitation Counil (UK) (2016) Advaned Life Support. Seventh Edition. RCUK, London. Ridler N, Plumb J, Groott M (2014) Oxygen therapy in ritial illness: friend or foe? A review of oxygen therapy in seleted aute illnesses. Journal of the Intensive Care Soiety. 15, 3, doi: / Royal College of Physiians (2017) National Early Warning Sore (NEWS) 2 Standardising the Assessment of Aute-Illness Severity in the NHS. outputs/national-early-warning-sore-news-2 (Last aessed: 10 July 2018.) Smith J, Rushton M (2015) How to perform respiratory assessment. Nursing Standard. 30, 7, doi: /ns s45. Stay KM (2014) Pulmonary anatomy and physiology. In Urden LD, Stay KM, Lough ME (Eds) Critial Care Nursing: Diagnosis and Management. Seventh edition. Elsevier, St Louis MO, Tortora GJ, Derrikson B (2017) Priniples of Anatomy and Physiology. 15th edition. John Wiley and Sons, Hoboken NJ. Ward JPT, Ward J, Leah RM (2015) The Respiratory System at a Glane. Fourth edition. Wiley-Blakwell, Oxford. Welh J, Blak C (2017) Respiratory problems. In Adam S, Osborne S, Welh J (Eds) Critial Care Nursing. Third edition. Oxford University Press, Oxford, Woodrow P (2016) Respiratory failure. In Nursing Autely Ill Adults. Routledge, Oxfordshire, nursingstandard.om RCN Publishing Company Limited 2018

8 ardiorespiratory / CPD multiple-hoie quiz Supplemental oxygen therapy TEST YOUR KNOWLEDGE BY COMPLETING THIS MULTIPLE-CHOICE QUIZ 1. Whih of the following is a ommon indiation for supplemental oxygen therapy? a) Cardia arrest b) Major pulmonary haemorrhage ) Anaphylaxis d) All of the above 2. What is one sign of deteriorating respiratory funtion? a) Inreased oxygen saturation b) Use of the aessory musles for inspiration or expiration ) Redued National Early Warning Sore d) Inreased energy 3. Supplemental oxygen: a) Never requires a presription b) Requires a presription if administered at high levels, but not if administered at moderate levels ) Is a presription-only drug, exept in an emergeny d) Must never be administered without a presription 4. Type II respiratory failure is defined as: a) Hypoxaemia with hyperapnia b) High oxygen ontent to the tissues and organs ) Hypoxaemia in the absene of hyperapnia d) Oxygen saturation of 100% 5. Whih of the following is not a potential risk assoiated with supplemental oxygen therapy and hyperoxaemia? a) Loss of hypoxi drive b) Worsening ventilation-perfusion (V/Q) mismath ) Rebound hypoxaemia d) Inreased ardia output 6. The pulmonary ventilation phase of respiration refers to: a) The mehanism of breathing: inspiration and expiration b) The exhange of oxygen and arbon dioxide between the alveoli and pulmonary apillary blood aross the respiratory membrane ) The movement of oxygen and arbon dioxide to and from the tissue ells d) The gas exhange that ours between the body tissues and the blood 7. Whih of these fators an affet the auray of pulse oximetry readings? a) Anaemia b) Peripheral vasoonstrition ) Nail varnish or false nails d) All of the above 8. As part of the exposure stage of a respiratory assessment using the ABCDE approah, healthare pratitioners should assess: a) Airway pateny b) Skin pallor for signs of yanosis ) Level of onsiousness d) Respiratory rate 9. Whih statement is false? a) Arterial blood gas is more aurate than pulse oximetry in measuring oxygen saturations within the arterial blood than pulse oximetry b) Arterial blood gas analysis enables diagnosis of respiratory or metaboli aidosis or alkalosis ) Arterial blood gas is less invasive, time-onsuming and expensive ompared with pulse oximetry d) Arterial blood gas measures partial pressure of oxygen and partial pressure of arbon dioxide in addition to oxygen saturation 10. What is one strategy that an be onsidered to relieve breathlessness? a) Close any open windows b) Use a handheld fan ) Assist the patient into a supine position to maximise ventilation d) Enourage the patient to undertake strenuous exerise How to omplete this quiz This multiple-hoie quiz will help you to test your knowledge. It omprises ten questions that are broadly linked to the CPD artile. There is one orret answer to eah question. You an test your subjet knowledge by attempting the questions before reading the artile, and then go bak over them to see if you would answer any differently. You might like to read the artile before trying the questions. Subsribers making use of their RCNi Portfolio an omplete this and other quizzes online and save the result automatially. Alternatively, you an ut out this page and add it to your professional portfolio. Don t forget to reord the amount of time taken to omplete it. Further multiple-hoie quizzes are available at rni.om/pd/test-yourknowledge This multiple hoie quiz was ompiled by Alex Bainbridge The answers to this multiple hoie quiz are: 1. d 2. b a 5. d 6. a 7. d 8. b b This ativity has taken me minutes/hours to omplete. Now that I have read this artile and ompleted this assessment, I think my knowledge is: Exellent Good Satisfatory Unsatisfatory Poor As a result of this I intend to: RCN Publishing Company Limited 2018 nursingstandard.om