Reducing Arterial Blood Gas Measurements in the Intensive Care Unit

Abstract

Background: An estimated 42% of laboratory testing performed in the hospital is considered wasteful or unnecessary. Unnecessary laboratory testing is associated with hospital-acquired anemia which in turn may cause significant morbidity, such as increased length of stay and increased frequency of blood transfusions. This project attempted to educate and provide feedback regarding inappropriate arterial blood gases (ABGs) on a medical intensive care unit (ICU), in order to reduce unnecessary testing.

Methods: Criteria for inappropriate ABG utilization were developed and are as follows: (1) Routine daily ABG measurements, (2) ABG after minor ventilator changes, and (3) Routine ABG after extubation. A preliminary retrospective chart analysis of all patients admitted to ICU in January 2018 who had an ABG performed revealed that 30% of ABG measurements were unnecessary based on these criteria. Pulmonary physicians and ICU nurses and respiratory therapists were provided education via lecture-format and emails regarding appropriate ABG utilization. The use of continuous capnography on ventilators was encouraged to guide therapy and prevent unnecessary ABG orders. Additional signs were posted on ventilators as a reminder to nurses and respiratory therapists that capnography measurement was ongoing and correlated to the most recent ABG to discourage unnecessary ABGs. The intervention start date was 11/4/2019.

Results: The number of ABG measurements was recorded in the ICU for three months before the intervention start date (Aug 2019-Oct 2019) and three months after the intervention start date (Nov 2019-Jan 2020). Prior to the intervention start there were 664.88 ABGs per 1,000 patient days. During the intervention period there were 515.66 ABGs/1,000 patient days. This was a 22.4 percent reduction in ABG measurements during the intervention period. We also compared the intervention period to the same three months from one year prior. In Nov 2018 to Jan 2019 there were 879.63 ABGs per 1,000 patient days. The intervention period in Nov 2019 to Jan 2020 had 41.4 percent fewer ABG measurements.

Conclusions: Laboratory testing is often unnecessary and wasteful and ABG measurements in ICUs are no exception. A multifaceted intervention to decrease inappropriate ABGs was employed on a closed ICU unit and included: education, the use of end-tidal capnography, feedback and empowerment. The intervention was successful and resulted in 22 percent decline in ABGs.