(162) Blood Gas Utilization in Cardiac Surgery ICU: Analysis and Opportunities for Improvement

Introduction: Blood gas analysis is a done frequently at our 18 bed cardiothoracic ICU to adjust ventilator settings and assess readiness for extubation. In addition, mixed venous gas is used to calculate the cardiac output and titrate inotropes and the level of mechanical circulatory support needed for cardiogenic shock. Almost 100 % of cardiac surgery patients and patients admitted with cardiogenic shock have arterial lines making the process of obtaining arterial blood gases extremely simple.
Due to the post Covid respiratory therapist shortage and the perception that many of those blood gases are not needed and drawn by inexperienced nursing staff, we performed an analysis of our blood gas usage and its appropriateness.

Methods: Using Device Workload Report of the blood gas analyzer machine , We created daily and monthly reports on ICU usages completed with all patient demographics and oxygen delivery method. We were also able to to determine the timing of the blood gas collection to discover the peak time of use.

Results: The average monthly number for blood gases drawn at our ICU is 968, with a daily average of 32 blood gases . Total average patients 80 /month
66.3 % of blood gases were ABG or ABG with lytes and 33.7% were mixed venous gases or venous gases.
67.4% off all gases were done during the night shift from 7PM-7AM and 60 percents of those were done between 12AM and 7PM.
9.5% of all ABGs were performed on patients on room air or oxygen via nasal cannula, all of which were drawn as part of the morning(AM) labs.
47.5 percent of ABGs on NC or RA were done in conjunction with a mixed venous gas.
58% of all ABG done on RA and or NC showed hypoxia, 16% hypercarbia, 20% alkalosis, and 9% acidosis.

Conclusions: Despite the perception that blood gases were over utilized, the percentage of unwarranted ABGs is small and is mostly done as a part of AM labs and or to support the validity of the mixed venous gas. However, unneeded labs could create increase workload especially for the night shift and contribute to extra cost and patient blood loss.
Avoiding automated EMR orders, discussing the need and frequency of blood gases during the multidisciplinary rounds and educating the staff regarding appropriate sampling of blood gases will help the respiratory therapist focus on necessary and impactful work.