From the 2018 HVPAA National Conference
Josh Marr (University of Utah School of Medicine), Amanda Breviu (University of Utah School of Medicine)
Background
Pulse oximetry was developed to monitor patients under anesthesia and has spread with limited data in the inpatient setting. It has shown limited benefit and increased length of stay in hospitalized infants with bronchiolitis1,2. Studies in post-surgical patients have shown no decrease in ICU transfer, mortality, or length of stay3,4.
Objectives
It remains commonplace to use continuous pulse oximetry (CPOX) monitoring on inpatient medical floors despite limited evidence, we sought to characterize patients who were placed on CPOX monitoring and its impact on hospital length of stay and ICU transfer.
Methods
We performed a retrospective cohort study of all patients who were admitted to a general medicine hospitalist service at a large academic medical center with a primary or comorbid diagnosis of respiratory failure between December 14, 2015 and July 31, 2017. Comparison groups were defined by whether an order was placed for continuous pulse oximetry monitoring during admission.
Results
The final analysis included 1192 patients, 659 (55.2%) were monitored with intermittent pulse oximetry and 533 (44.7%) had continuous pulse oximetry monitoring. The most common primary admission diagnoses included: sepsis (31.6%), respiratory failure (15.2%), heart failure (5.5%), and VTE (4.9%). Monitored patients were younger (60.9 years vs 63.6 years, p=0.006) and had a higher comorbidity burden by MS-DRG (2.0 vs 1.7, p=0.002). CPOX patients were more likely to be intubated (5.1% vs 1.4%, p<0.001), transferred to the ICU (15.6% vs 3.8%, p<0.001), and given a new prescription for oxygen on discharge (30.6% vs 23.2%, p=0.004). Length of stay was longer among monitored patients (5.2 days vs 4.1 days, p<0.001). Mortality did not differ between groups (1.1% vs 0.9%, p=0.831). Monitored patients were more likely to be transferred to the ICU (OR 3.6, CI 2.1-6.0) when controlling for age, sex, and severity of illness.
Conclusion
Our findings question the benefits of using continuous pulse oximetry in the inpatient setting. CPOX monitoring was associated with more frequent ICU transfers and an increased length of stay with no measurable change in mortality. One potential explanation is that nurses or physicians are more likely to order continuous pulse oximetry on patients they identify as being at risk for decompensation, as evidenced by the higher MS-DRG score. Further research into the potential benefit and cost-effectiveness of continuous pulse oximetry in this population is warranted.
Implications for the Patient
Continuous pulse oximetry monitoring was associated with an increased length of stay and more frequent ICU transfers in general medicine hospitalized patients.
