P068: Significance of asymptomatic oxygen desaturation in elderly ED patients: A pilot study

Abstract

Introduction: Pulse oximetry is a standard component of Emergency Department (ED) patient monitoring. Pulse oximetry measures peripheral capillary oxygen saturation (SpO2) levels and can be used to monitor cardiorespiratory conditions. The normal SpO2 level for adults is approximately 96%. Oxygen saturations of <92% are considered problematic and levels <90% may indicate cardiorespiratory disease. However, low oxygen saturations are often seen in elderly patients with comorbidities. This research investigated the significance of hypoxia in asymptomatic older ED patients with no apparent acute illness. Methods: ED patients >75 years with a documented room air pulse oximetry reading <92% were eligible. Exclusion criteria included dyspnea, chest pain, SBP <100mmHg, HR >120 or <50; sustained tachypnea (RR > 20); acute cardiopulmonary conditions, delirium or acutely altered mentation. Eligible patients were separated into two groups: 1) Sustained hypoxia: two or more SpO2 readings <92% 2) Unsustained hypoxia: one SpO2 reading <92%. 30-day adverse events were tracked using a Sunrise Emergency Care record review. Adverse outcomes investigated included death, MI, CHF, PE, cardioversion, ICU admission, intubation, ED revisit or re-hospitalization. Patient characteristics studied were age, sex, arrival mode, triage complaint, CTAS level, pulse, BP, RR, weight, residence (independent, assisted living, facility), comorbidities, PHN, referral, disposition, and test results (CXR, troponin, ECG, CT). Follow-up phone calls were completed after 30 days to assess patient status and confirm ED revisit. Results: A total of 876 ED patients >75 years were screened and 30-day follow-up data was analyzed for 34 enrolled patients. The sustained hypoxia group (n = 23) showed higher rates of 30-day adverse outcomes of death, ED re-visitation, MI, CHF, a severe episode of COPD, PE and ICU stays compared to the unsustained hypoxia group (n = 11). Administrative data of 31,095 patients >75 years from four Calgary EDs in 2017 was also analyzed and 7,771 (20%) were hypoxic at triage (SpO2 <92%). Adverse outcomes and mortality were significant in discharged hypoxic patients (especially if SpO2 <90%). Conclusion: ED re-visits, cardiorespiratory complications, and mortality were significant in discharged sustained hypoxic patients, especially if O2 sat <90%. Pulse oximetry assessment of oxygen saturation in seniors’ care facilities and physicians’ offices may be important in screening for future adverse health outcomes in elderly patients.