In this analysis, we found that higher case volume for joint arthroplasty anesthesia for the attending anesthesiologist was associated with decreased times in both time from patient arrival to OR and anesthesia ready and time from incision to closure complete. While the findings were statistically significant, the number of minutes saved likely does not transfer to any clinically significant changes. For example, when we compared anesthesiologists with median case volume (79 cases) versus those with the lowest case volume (10 cases), the predicted difference in times added up to only ~ 6 min. Furthermore, the mixed effect models had low calculated ICCs (< 0.1), which suggested little similarity within each cluster (i.e. anesthesiologist). The results suggest that there may be some influence of the individual anesthesiology provider and their historic case volume in relation to intraoperative efficiency for joint arthroplasty cases, but the influence is small. If the purpose of faster anesthesia workflows was to open up more OR time to increase surgical volume in a given day, this study does not support the supposition that anesthesiologists with higher joint arthroplasty case volume would improve throughput. Of note, our study did not measure perioperative complication rates or postoperative outcomes as it relates to an anesthesiologist’s case volume experience. Thus, while this study does not support need for higher volume anesthesiologists to improve OR throughput for joint arthroplasty anesthesia, more studies are needed to determine if there is an impact on improved patient outcomes.

Some authors have described the benefit of a dedicated group of regional anesthesiologists to perform spinal anesthetics to maximize efficiency and minimize complications [11]. In this study, the association of anesthesiologist case volume and time between patient OR arrival and anesthesia ready was small, thus this may not translate into any real-time savings when performing joint arthroplasty. In fact, ASA PS classification score had the largest impact on time on anesthesia induction – approximately 7 min added in patients that were ASA PS 4. Others have found that parallel processing was beneficial when a dedicated bay in the preoperative area was used to perform spinal anesthesia before a patient was brought into the OR [11, 16, 19]. For instance, Smith et al. found that nonoperative time decreased by 36 min (or 50%) and operative time decreased by 14 min (12%) for each case with this protocol [16]. While this is one solution, it would be dependent on the availability of extra anesthesia teams, nursing, and space resources.

Although the results of this study do not promote the need for anesthesiology teams consisting of those with the most experience in joint arthroplasty anesthetics, it is still vital to prioritize technical competency in providing anesthetic care for these patients. There was also controversy if spinal anesthesia may improve outcomes for joint arthroplasty patients by reducing morbidity and mortality [20]. The REGAIN trial showed that spinal anesthesia did not increase survival or recovery of ambulation at 60 days after surgical repair for hip fractures when compared to general anesthesia [21]. In contrast, Memtsoudis showed that the use of neuraxial anesthesia for primary joint arthroplasty might confer a protective effect, while decreasing the incidence of thromboembolism, postoperative systemic infection [22], surgical time, and blood loss [23, 24].

While the clinical implication of spinal anesthesia is becoming more apparent, the implication on efficiency and money-saving initiatives are unclear. The average OR cost is around $36–37 per minute [25]. The operative time (block time) is fixed for a particular surgeon or service. When looking at OR efficiency, spinal anesthesia has been shown to increase the time to prepare the patient for surgery and total preoperative time while the time to remove the patient from the OR was significantly reduced. However, these differences cancel out when considering total OR time compared to general anesthesia [12].

Spinal anesthesia can be more challenging to perform due to the inherent characteristics of every patient and, as a result, could be less predictable in onset; however, once a surgical block is established, then spinal anesthesia may overall be less involved (compared to general anesthesia), and time related to emergence is minimal in the OR when compared to general anesthesia. Park showed that spinal anesthesia was associated with mild overall time saving compared to general anesthesia [26] and Chandler found no overall differences in nonoperative time between spinal anesthesia and general anesthesia [12].

This study focused on measuring the association of joint arthroplasty case volume experience of anesthesiologists with intraoperative efficiency. No meaningful clinical differences were found, as noted before. Actual time-saving initiatives may come from other approaches to OR times. Having a dedicated bay to perform regional and neuraxial anesthesia in the preoperative area has consistently shown adequate time and money savings [18, 25]. Furthermore, reducing surgical skin time could potentially have the largest impact on OR time saving and thus the potential to increase OR volume. Furthermore, trainee and CRNA involvement was measured, and we found no differences in intraoperative efficiency. Previous literature has reported trainee involvement to have no effect on anesthesia-controlled times [27] and minimal effect on emergence time [28].

We recognize that the study has some limitations. Given the retrospective nature of the study, there are inherent limitations related to accuracy of data. For example, OR time metrics were recorded by the circulating nurse, which could potentially introduce bias. However, this was done systematically and uniformly and potentially unlikely to skew the results to certain anesthesiology providers. To further validate the results of this study, a prospectively-designed clinical trial could better demonstrate the impact of having specialty anesthesiology teams for this surgical population, and whether this could improve overall OR utilization. More studies are needed to identify if OR and anesthesia-controlled times are linked to a particular anesthesia technique or more related to the resources and space available to implement more parallel processing. Another limitation is that we did not study association of case volume experience with postoperative outcomes, such as complications or hospital length of stay. These are important metrics that may be affected by the anesthesia care. Thus, our study is limited to providing data regarding the association of case volume experience with OR efficiency, but not postoperative outcomes.

In conclusion, based on this retrospective study of nearly 5,000 surgical cases, there were statistically significant but not clinically significant associations between an anesthesiologists’ joint arthroplasty anesthesia volume and operating room time – specifically time between patient arrival to OR and anesthesia ready and time between start of surgical incision to closure complete. The differences were not clinically significance as the measured time saved would not be sufficient to effectively add more joint arthroplasty surgeries in a given OR day. This study would then suggest that dedicated anesthesiologists with the most joint arthroplasty anesthesia volume for a joint arthroplasty surgery may provide limited benefit for improving throughput. However, future studies should measure associations with perioperative complications and postoperative outcomes as it relates to the anesthesiologist’s case volume experience.