"Knife to skin" time is a poor marker of operating room utilization and efficiency in cardiac surgery

Predictors of anesthesia ready time: Analysis and benchmark data

Objective

Patients undergoing congenital cardiac surgery require induction of anesthesia. Our objective was to identify the median anesthesia ready time and the predictors of this time.

Methods

By using the Society of Thoracic Surgeons Congenital Heart Surgery Database, we identified patients who underwent cardiopulmonary bypass procedures from 2017 to 2021. Univariate and multivariable regression modeling to predict the anesthesia ready time was performed using mixed-effects linear regression.

Results

After exclusion of outliers, 44,418 cases were analyzed. The median anesthesia ready time was 51 minutes (interquartile range, 38-66). On multivariable analysis, independent predictors of a longer anesthesia ready time included decreasing weight (0.3 min/10 kg, 95% CI, 0.1-0.6; P = .011), prematurity (1.5 minutes, 95% CI, 0.8-2.2; P < .001), and presence of chromosomal abnormality (3.4 minutes, 95% CI, 1.5-5.2; P < .001). An increase in the duration in anesthesia ready time was seen with increasing Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery mortality category with an additional 7.8 minutes (95% CI, 5.2-10.4; P < .001) for a Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery 5 procedure compared with Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery 1. Emergency versus elective case designation was associated with an anesthesia ready time reduction of 3.6 minutes (95% CI, 1.1-6.1; P = .005), and an afternoon case start was associated with an anesthesia ready time reduction of 4.2 minutes (95% CI, 2.8-5.6; P < .001). The presence of an anesthesia trainee increased the anesthesia ready time by 3.8 minutes (95% CI, 2.6-5.0; P < .001). The presence of an airway in situ decreased the anesthesia ready time by 3.6 minutes (95% CI, 1.6-5.5; P < .001), whereas an in situ arterial line decreased the anesthesia ready time by 7.4 minutes (95% CI, 4.6-10.2; P < .001). Placement of a central venous line increased the anesthesia ready time by 8.5 minutes (95% CI, 5.9-11.1; P < .001).

Conclusions

The median anesthesia ready time was 51 minutes. For patients with characteristics associated with prolonged anesthesia ready time, consideration should be given to allocation of additional anesthesia staffing to improve efficiency.

Getting operating theatre metrics right to underpin quality improvement: understanding limitations of NHS Model Hospital calculations

The Model Hospital is an NHS online resource summarising performance data for, amongst other things, operating theatres categorised by NHS Trust and specialty. As an official source of information, it might be assumed that metrics, such as 'average late start time', 'average early finish time', and 'average late finish time', are calculated in a way to reflect performance in these domains, but this is not the case. These values are, respectively, only for those lists that start late, finish early, and finish late, with the number of lists in each category unreported. The Model Hospital reports utilisation appropriately as 'touch time' (the time delivering anaesthesia and surgery) but prefers a 'capped' measure, in which any touch time occurring in late finishes is ignored. The Model Hospital aggregates utilisations across lists in a mathematically invalid way, which leads to the assumption that small aliquots of unused time on lists can be combined to create larger time blocks, in which to complete more operations. We present alternative, more intuitive, and mathematically conventional methods to derive performance metrics using the same data. The results have implications for hospitals developing their own dashboards and international organisations seeking to create national databases for operating theatre performance.

Compared efficiency of trauma versus scheduled orthopaedic surgery operating rooms in a university hospital

BACKGROUND

The objective of this study was to contribute to an OR efficiency optimisation effort by comparing a trauma OR versus a scheduled surgery OR in a lower limb orthopaedic surgery department.

HYPOTHESIS

The main hypothesis is that efficiency is lower in the trauma OR than in the scheduled surgery OR. The secondary hypothesis is that efficiency of the trauma OR is lower during weekends.

MATERIAL AND METHODS

This prospective study was conducted in 2016 in the orthopaedic surgery department of a university hospital. Patients were divided into three groups based on whether they underwent scheduled surgery (SchOS), trauma surgery on a weekday (TSwk), or trauma surgery on a weekend (TSwkend). Actual OR occupancy time, allocated OR block time (BT), OR occupancy rate, patient entrance-to-incision time, incision-to-closure time, closure-to-post-anaesthesia care unit (PACU) entrance time, and clean-up/set-up time (T4) were measured.

RESULTS

We included 691 patients in the SchOS group, 819 in the TSwk group, and 327 in the TSwkend group. OR efficiency was lower in the TSwk group compared to the SchOS group (occupancy rate, 86% vs. 88%; p=10^-4). All occupancy time components were longer in the TSwk group. However, each component accounted for similar total occupancy time proportions in the two groups, except for clean-up/set-up time, which was longer in the TSwk group (p<0.05). On average, entrance-to-incision time accounted for 31%, incision-to-closure time for 34%, closure-to-PACU time for 18%, and clean-up/set-up time for 17% of total occupancy time. Efficiency was lower in the TSwkend group than in the TSwk group (occupancy rate, 75% vs. 86%; p=10^-4). The TSwkend group had shorter entrance-to-incision and incision-to-closure times (p<0.05) and a nearly 10% longer clean-up/set-up time (p<0.05).

CONCLUSION

Efficiency of the trauma OR, although lower compared to the scheduled orthopaedic surgery OR, was nevertheless satisfactory as assessed based on standard indicators. Of the four total occupancy time components, the first three accounted for similar proportions of the total; differences occurred only for clean-up/set-up time. Efforts to improve OR efficiency should focus on arrival of the first patient and turnover time.

LEVEL OF EVIDENCE

II, prospective cohort study.