Outpatient imaging for pulmonary embolism may only be suitable for a minority

In this study we model the impact of introducing outpatient investigation of pulmonary thrombo-embolism (PTE) to the acute medical unit (AMU) using the Pulmonary Embolism Severity Index (PESI) decision rule. Specifically, we ask what proportion of patients requiring imaging could be investigated without admission, and how many bed-days this would save.  We obtained records for all medical patients who had imaging for PTE in a six-month period at a large teaching hospital with a 40-bedded AMU. The patients were categorized into suitability for outpatient investigation using a combination of the PESI rule and practical considerations. Three hundred and fifty-nine separate presentations were identified. From available records, 31 patients (9.2%, 95% confidence interval [CI] 6.6-12.8%) had no contraindications to outpatient management. These patients used a total of 79 bed-days in the six-month period, or 1.1% (95% CI 0.8-1.5%) of the maximum AMU bed occupancy. Around 10% of patients who require imaging for suspected PTE could be triaged to outpatient investigation using the PESI tool. Adopting this method to triage patients of ambulatory care, would have only a modest effect on acute medical bed occupancy, but remains a valid option for motivated patients in the low-risk category.