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Guided Learning

Emergency oxygen delivery: patients with asthma and COPD

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This article outlines recommendations in British Thoracic Society guidance on oxygen therapy inpatients with asthma and COPD

Abstract

Smith, S.M.S. et al (2009) Emergency oxygen delivery 2: patients with asthma and COPD. Nursing Times; 105: 11.

This is the second of a two-part unit on the use of emergency oxygen in adults. Part 1 outlined the main recommendations of the recently published British Thoracic Society guidance. It also examined managing breathlessness in non-hypoxaemic patients, including those with lung cancer.

This part discusses some potential changes to clinical practice and provides practical examples on administering oxygen to patients with acute asthma and COPD. It also outlines issues around administering oxygen that lack evidence and need good-quality studies.

Keywords: Respiratory care, Oxygen, Asthma, COPD

This article has been double-blind peer reviewed

 

Authors

Sheree M.S. Smith, PhD, MSocPlanDev, Cardiothoracic Cert, GNCert, BN, RN, is research manager, St Mary’s Hospital, London; Sian B. Roberts, MSc, BSc, RN, ENB 254, is thoracic nurse specialist, St Mary’s Hospital, London, and Vancouver General Hospital, Canada; Michelle Duggan-Brennan, Asthma Dip, DipHEd Nursing, RGN, is asthma nurse specialist; Kathryn E. Powrie, Asthma Dip, Allergy Dip, BN, RN, is asthma and allergy nurse specialist; both at St Mary’s Hospital, London; Rachel Haffenden, MA, BSc, RGN, is clinical service manager, respiratory services, Charing Cross Hospital, London; all at Imperial College Healthcare NHS Trust.

 

Learning objectives

  1. Know how to manage acute exacerbations of asthma in hypoxaemic patients.
  2. Understand how to manage hypoxaemic patients with COPD.

 

Introduction

The first national guidance on using emergency oxygen in acutely ill adults was published by the British Thoracic Society (O’Driscoll et al, 2008).

Part 1 of this unit addressed some of the central terms associated with oxygen therapy. It also discussed evidence-based modalities for managing breathlessness in adult patients, as this therapy has been found to be of little benefit in these cases.

This part discusses some important changes to oxygen therapy and the need for change in clinical practice and local policy. In addition, it examines using this therapy for adults with acute asthma and those with COPD. It draws on current guidelines on managing asthma and COPD exacerbations to ensure the most up-to-date information is given (Scottish Intercollegiate Guidelines Network and BTS, 2008; BTS Standards of Care Committee, 2004).

 

Oxygen therapy and asthma

The SIGN and BTS (2008) asthma guideline contains completely revised sections on diagnosis, pregnancy, asthma that is difficult to manage and updated information on pharmacological and non-pharmacological management.

The section on treatment for acute asthma in adults suggests that higher concentrations of inspired oxygen may be needed. When high-flow oxygen is given, it is necessary to ensure that high-flow masks such as Hudson or MC masks are used so the desired concentration of inspired oxygen can be reached.

This advice is confirmed in the emergency oxygen use guideline (O’Driscoll et al, 2008). It also gives additional information for critically ill patients on the need for higher concentrations of oxygen (60–90%) when using reservoir masks (non-rebreathing masks).

Oxygen therapy for acute asthma aims to achieve oxygen saturations of at least 92%. However, the emergency oxygen guidance suggests a range of 94–98% for all situations if possible. When adults with severe acute asthma need nebulised medications, often described as wet nebulisation, the guidance recommends that these are delivered via oxygen-driven nebulisers.

The guideline also includes an algorithm for clinical management of adults with severe acute asthma in A&E, and this may help healthcare professionals to provide optimal care at this very challenging and critical time for patients.

 

Oxygen therapy and COPD

People with COPD have different pathophysiology compared with those with asthma. In particular, people with COPD often experience exacerbations with decreasing lung function after each episode (Wedzicha and Donaldson, 2003).

An exacerbation is the sustained worsening of patients’ symptoms such as breathlessness, cough, increased sputum production and change in sputum colour (BTS Standards of Care Committee, 2004).

The outcomes for these patients can be catastrophic after hospital discharge, with 34% being readmitted and 14%dying within three months (BTS Standards of Care Committee, 2004).

In patients with COPD who are experiencing an exacerbation, the guidance recommends that they be given oxygen therapy via a venturi mask at either 28% with flow rate of 4L per minute or 24% with a flow rate of 2L per minute (O’Driscoll et al, 2008).

The target level in the BTS COPD guidelines indicates that an oxygen saturation level of 90% or above should be achieved and maintained with oxygen therapy. This level of saturation in the COPD guideline is consistent with the emergency oxygen one, which recommends that a range of 88–92% as acceptable (O’Driscoll et al, 2008). In addition, the oxygen guidance highlights the importance of assessing each individual patient and analysing arterial blood gas measurements in conjunction with their clinical history.

Furthermore, in patients with COPD there may be some who have had an episode of hypercapnic respiratory failure and high oxygen concentrations may worsen their condition. Although COPD patients with hypercapnic respiratory failure are not common (around 10%) (Plant et al, 2000), it is important to identify such people as they need specific precautions while receiving low concentrations of oxygen therapy.

The guidance also recommends oxygen alert cards for patients with high-risk conditions such as kyphoscoliosis, respiratory failure due to neuromuscular conditions or known type 2 respiratory failure. These patients should be instructed to show ambulance and A&E staff these alert cards to ensure safe and correct prescription and administration of oxygen therapy.

The oxygen guideline also includes detailed information and working examples of oxygen prescription charts as well as examples of specific respiratory charts that incorporate patient observations such as respiratory rates with oxygen saturation values and oxygen therapy details.

 

Other practical issues

Both those with asthma and those with COPD can develop mucous plugging and there is little evidence that humidification with high-flow oxygen is effective and the oxygen guideline recommends that a bubble bottle should not be used (O’Driscoll et al, 2008). However, single doses of nebulised normal saline (sterile isotonic normal saline ampoules) have been shown to help in sputum clearance and reduce breathlessness in patients with COPD (Khan and O’Driscoll, 2004; Poole et al, 1998).

A recurring theme in the BTS oxygen guideline is the use of the appropriate device and flow rate to achieve the target oxygen saturation range. For those with asthma and COPD, nasal cannulae may be used to deliver the required percentage of oxygen in an acute situation after the initial phase of treatment. This guidance highlights the impact of patients’ breathing patterns on oxygen flow rates and other considerations when using nasal cannulae. We would advise all nurses to read this important section to ensure optimal use of nasal cannulae.

 

Further research

To integrate this guideline into local policy, it may be necessary to re-evaluate existing policies that incorporate oxygen therapy, such as those on caring for patients with asthma or COPD.

O’Driscoll et al (2008) suggested staff education as the vehicle to enhance clinical implementation of the guidance. However, the best method for educating staff is unclear, since there are many and diverse clinical areas where oxygen therapy is administered. This is a potential area of further research for nurses.

Furthermore, the BTS guidance on emergency oxygen use also identifies a substantial list of issues for further research. Many of these topics could be undertaken by nurses with research expertise to ensure rigorous studies that produce sound clinical evidence.

 

Conclusion

The new BTS guideline on emergency oxygen use in adults provides recommendations that are consistent with current asthma and COPD guidance. It also provides more detailed information on assessing patients, oxygen prescription and administration, and monitoring and maintaining target saturations.

The diagnoses of asthma and COPD differ and so do prescriptions for oxygen therapy, as each diagnostic group and individual patients have their own physiological and pathophysiological needs. The emergency oxygen guideline provides a list of potential research questions, some of which nurses with research expertise may consider undertaking.

Finally, we would recommend that all nurses read the new BTS guidelines, irrespective of their clinical area, to ensure that their practice stays up to date.

 

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