Racial Disparities in Occult Hypoxemia and Clinically Based Mitigation Strategies to Apply in Advance of Technological Advancements.

BACKGROUND: Pulse oximetry is the mainstay of patient oxygen monitoring. Measurement error from pulse oximetry is more common for those with darker skin pigmentation, yet this topic remains understudied, and evidence-based clinical mitigation strategies do not currently exist. Our objectives were to measure the rate of occult hypoxemia, defined as arterial oxygen saturation (SaO2 ) < 88% when pulse oximeter oxygen saturation was between 92-96%, in a racially diverse critically ill population; to analyze degree, direction, and consistency of measurement error; and to develop a mitigation strategy that minimizes occult hypoxemia in advance of technological advancements. METHODS: We performed a multi-center retrospective cohort study of critically ill subjects. RESULTS: Among 105,467 paired observations from 7,693 subjects, we found occult hypoxemia was more common among minority subjects. The frequency of occult hypoxemia was 7.9% versus 2.9% between Black and white subjects, respectively, (P < .001). Pulse oximeter measurement errors were inconsistent throughout a patient encounter, with 67% of encounters having a range of intra-subject measurement errors > 4 percentage points. In 75% of encounters, the intra-subject errors were bidirectional. SaO2 < 88% was less common at higher pulse oximeter oxygenation ranges (4.1% and 1.8% of observations among Black and white subjects at a pulse oximeter threshold of 94-98%). Although occult hypoxemia was further reduced at oxygenation saturation range 95-100%, the frequency of hyperoxemia (partial pressure of arterial oxygen > 110 mm Hg) became more common, occurring in 42.3% of Black and 46.0% of white observations. CONCLUSIONS: Measurement error in pulse oximetry is common for all racial groups, but occult hypoxemia occurred most commonly in Black subjects. The highly variable magnitude and direction of measurement error preclude an individualized mitigation approach. In advance of technological advancements, we recommend targeting a pulse oximetry saturation goal of 94-98% for all patients.

Characteristics, Outcomes, and Trends of Patients With COVID-19-Related Critical Illness at a Learning Health System in the United States.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic continues to surge in the United States and globally. OBJECTIVE: To describe the epidemiology of COVID-19-related critical illness, including trends in outcomes and care delivery. DESIGN: Single-health system, multihospital retrospective cohort study. SETTING: 5 hospitals within the University of Pennsylvania Health System. PATIENTS: Adults with COVID-19-related critical illness who were admitted to an intensive care unit (ICU) with acute respiratory failure or shock during the initial surge of the pandemic. MEASUREMENTS: The primary exposure for outcomes and care delivery trend analyses was longitudinal time during the pandemic. The primary outcome was all-cause 28-day in-hospital mortality. Secondary outcomes were all-cause death at any time, receipt of mechanical ventilation (MV), and readmissions. RESULTS: Among 468 patients with COVID-19-related critical illness, 319 (68.2%) were treated with MV and 121 (25.9%) with vasopressors. Outcomes were notable for an all-cause 28-day in-hospital mortality rate of 29.9%, a median ICU stay of 8 days (interquartile range [IQR], 3 to 17 days), a median hospital stay of 13 days (IQR, 7 to 25 days), and an all-cause 30-day readmission rate (among nonhospice survivors) of 10.8%. Mortality decreased over time, from 43.5% (95% CI, 31.3% to 53.8%) to 19.2% (CI, 11.6% to 26.7%) between the first and last 15-day periods in the core adjusted model, whereas patient acuity and other factors did not change. LIMITATIONS: Single-health system study; use of, or highly dynamic trends in, other clinical interventions were not evaluated, nor were complications. CONCLUSION: Among patients with COVID-19-related critical illness admitted to ICUs of a learning health system in the United States, mortality seemed to decrease over time despite stable patient characteristics. Further studies are necessary to confirm this result and to investigate causal mechanisms. PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality.