1. Limit ABGs.
ABGs are usually unnecessary in patients with asthma or COPD, especially if the PEFR is greater than 25% of the predicted value. If a patient has a normal pulse oximetry on room air, an arterial blood gas is not necessary to rule out hypoxemia.
Risk Management Caveat: ABGs are useful in patients with altered mental status, suspected acidosis, and in those likely to have CO2 retention. Arterial blood gases may provide important information regarding the A-a DO2 gradient data, which is unobtainable by pulse oximetry. A widened A-a DO2 gradient in the patient with unexplained dyspnea may be due to a variety of causes, including pulmonary embolism and pneumonia. 2. Limit V/Q scans to patients likely to have PE.
A V/Q lung scan is usually unnecessary in a patient with a low clinical risk for PE and a normal new-generation D-dimer assay (< 500 ng/mL).
Risk Management Caveat: Use a new-generation test such as the SimpliRED assay, not a latex agglutination test. Be sure that the patient is at low clinical risk and has no prior history of thromboembolic disease or cancer; no recent trauma, surgery, or immobilization; and no family history of PE or DVT.3. Limit chest x-rays in asthma and COPD.
Patients with a prior history of asthma or COPD do not need a chest film for every ED visit. Limit radiography to patients who fail to improve despite adequate ED herapy or those with a likely comorbid condition such as pneumonia or pneumothorax.
Risk Management Caveat: Patients with fever and no evidence of a upper respiratory infection and those with markedly asymmetrical breath sounds are more likely to have significant chest x-ray findings. Other high-risk factors include immune suppression, history of cardiac disease, altered mental status, severe dyspnea, or advanced age. 4. Limit portable chest films to unstable patients.
Order PA and lateral chest x-rays in all but unstable patients. Portable AP films are more expensive and less accurate for pathology.
Risk Management Caveat: Unstable patients should remain in a resuscitation area on a monitor. 5. More metered-dose inhalers?fewer nebulizers.
Metered-dose inhalers with spacer chambers are at least as effective as hand-held nebulizers in the treatment of asthma and COPD?and are significantly less expensive.
Risk Management Caveat: Be sure to use a spacer chamber, as this will dramatically increase the effectiveness of the MDI in most patients. The use of the MDI and spacer, while well-studied in cases of mild-to-moderate disease, has not been rigorously tested in patients with life-threatening bronchospasm. It may be prudent to use nebulizer therapy and perhaps continuous nebulization in this population. 6. Consider the helical CT.
Patients suspected of PE who have an infiltrate on chest x-ray are very likely to have a non-diagnostic V/Q scan. Consider a contrast-enhanced helical CT in such patients.
Risk Management Caveat: Helical CT is very readerdependent. Ask your radiologist about how comfortable he or she is in interpreting the study for emboli. The scanner must be a late-generation helical device to achieve acceptable accuracy. While an expert reader is unlikely to miss a large central embolism on helical CT, small peripheral emboli may remain occult. In patients at high risk for PE, a subsequent angiogram may be necessary despite a negative CT.