January 27, 2009
Oxygen Therapy: Everything You Wanted to Know and More!
In our April 8, 2008 Patient Safety Tip of the Week “Oxygen as a Medication” we discussed both the benefits and risks of oxygen therapy. We followed this up in June 2008 with “Monitoring the Postoperative COPD Patient”. In the latter we alluded to the upcoming publication by the British Thoracic Society of a new comprehensive guideline on oxygen therapy. That has been published in the journal Thorax in October 2008 and the British Thoracic Society website includes not only the guideline but a whole host of incredibly useful downloadable tools for managing oxygen therapy.
The guideline was developed by a multidisciplinary group representing multiple different specialty groups in the UK after audits showed multiple problems with oxygen use and significant lack of agreement on issues related to oxygen use.
The full guideline is 81 pages but there is a 10-page executive summary and a separate summary for hospital use. They provide a sample audit tool and samples of what the oxygen “prescription” should look like. A sample hospital oxygen therapy policy is also available for download. There are even PowerPoint presentations for use in education of your physician and nursing staffs and an educational handout for patients.
The philosophy of the guideline is straightforward. Oxygen is a “drug”, in fact one of the most widely used drugs in healthcare. It should be used for the treatment of hypoxemia, not breathlessness. It should be prescribed toward a target saturation range. That target saturation range will be lower in those patients at risk for hypercapnic respiratory failure (eg. COPD, certain neuromuscular disorders, chest wall deformities, massive obesity). Patients should be assessed and monitored appropriately, with complete documentation in the chart. And oxygen should be discontinued when it is no longer necessary.
The guideline contains tables identifying which medical conditions commonly require oxygen therapy. Just as importantly, it contains a table of common medical conditions where oxygen is not necessary unless the patient is hypoxemic. The latter include conditions such as acute MI and stroke. For years we routinely put such patients on oxygen and we’ll bet you can find some such patients in your hospital today!
The guideline has a comprehensive discussion on the various methods of oxygen delivery and good sections on related issues (humidification, nebulizers, etc.). The full guideline also has an excellent section on physiology and discusses the benefits of oxygen therapy but also discusses the potential harms of hyperoxia and hypercapnia.
Perhaps most useful are the recommendations for safeguarding patients at risk of hypercapnic respiratory failure during oxygen therapy (eg. COPD, certain neuromuscular disorders, chest wall deformities, massive obesity). This includes the lower target saturation range (88-92%), use of controlled oxygen via Venturi masks, appropriate education of patients and healthcare workers, use of alert cards, and issue of personal Venturi masks to high risk patients. Because of limitations of noninvasive methods for monitoring for hypercapnia (such as use of end-tidal carbon dioxide measurement), they stress observation for the clinical signs of hypercapnia (vasodilation, bounding pulse, flapping tremor, drowsiness, confusion and coma). While the target oxygen saturation for most acutely ill patients is 94-98%, in those patients at risk for hypercapnic respiratory failure the target range is recommended to be 88-92% pending availability of arterial blood gas results. It is recommended that those patients with a history of previous hypercapnic respiratory failure carry an alert card that contains recommendations about the ideal oxygen dose and target saturation range for that individual patient. A sample oxygen alert card is included in the March 2008 AHRQ Web M&M case that we discussed previously. This facilitates a patient at risk of CO2 retention in getting the most appropriate oxygen concentration/flow with the correct target saturation range.
The guideline recommends usage of a preprinted section for oxygen prescription in the order section of patient charts (in the medication section). They provide good examples of such preprinted orders. Such could also be easily adapted for computerized order entry. And, just as for drugs, appropriate documentation of the administration of oxygen and it monitoring is required.
The oxygen prescription should include the desired target saturation range and the method of delivery (appropriate device and flow rates to maintain that saturation in the target range). Rather than using a “fixed dose” of oxygen, as has been the typical practice in most hospitals, the guideline stresses adjustment of the dosage to achieve the target oxygen saturation. Oxygen saturation is the “5th vital sign” and the guideline discusses the value and nuances of using pulse oximetry to measure oxygen saturation, as well as its limitations. It provides advice on the appropriate use of arterial blood gas (ABG) analysis as well. They note the limitations of noninvasive methods for monitoring for hypercapnia (such as use of end-tidal carbon dioxide measurement).
The guideline contains useful algorithms that step one through the important questions to ask when beginning a patient on oxygen therapy, starting with the question “Is the patient at risk for hypercapnic respiratory failure?”. The answer to that question not only helps establish the saturation target range but also helps determine initial oxygen concentration and delivery method and monitoring methods.
The guideline discusses in detail use of oxygen in emergency and prehospital settings and in other special circumstances (such as obstetrics, near-drowning, carbon monoxide poisoning, etc.). It also has an extensive discussion about oxygen delivery devices and practical advice about topics such as oxygen storage. It has a section on oxygen use and issues during patient transport that complements our previous discussions on transport issues (see Patient Safety Tips of the Week “Oxygen as a Medication” and “Ticket to Ride: Checklist, Form, or Decision Scorecard?”).
The importance of staff education and development of local oxygen “champions” are emphasized. The PowerPoint slides they provide are excellent educational materials. They have sets for physicians and sets for nursing and other healthcare professionals.
A good understanding about oxygen therapy is critical for the safety and wellbeing of your patients. A good oxygen management program will also likely be beneficial to the economic wellbeing of your hospital. Reading and understanding the BTS Guideline should be a good first step in your organization’s efforts to improve the safety and efficacy of oxygen management.
Update: See our April 2009 What’s New in the Patient Safety World column “Nursing Companion to the BTS Oxygen Therapy Guidelines” and our October 6, 2009 Patient Safety Tip of the Week “Oxygen Safety: More Lessons from the UK”.
O’Driscoll BR, Howard LS, Davison AG and the British Thoracic Society. Emergency Oxygen Guideline Group. BTS Guideline Emergency Oxygen Use in Adult Patients. Thorax 2008; 63 (suppl. VI): 1-68
Full guideline (81 pages)
O'Driscoll BR, Howard LS, Davison AG on behalf of the British Thoracic Society BTS guideline for emergency oxygen use in adult patients. Thorax 2008; 63 (suppl. VI): 1-68