When Every Minute Matters: What New Research Shows About OR Workflow Variation and Care Quality

Operating room efficiency is usually discussed in terms of capacity: cases per room, utilization, turnover time, FCOTS, and late-running rooms. But some of the same workflow variation that costs a hospital capacity can also have consequences for patient care.

New research from Houston Methodist and Apella, published in theJournal of Vascular Surgery — Vascular Insights, examined lower-extremity angiography cases — procedures used to evaluate and treat blood flow problems in the legs — across five hospitals in the same health system. Even for this standardized procedure, median total case duration ranged from 115 to 182 minutes across sites, a difference of more than an hour.

For perioperative leaders, that degree of variation immediately raises questions: 

• Why can one site complete the same type of case so much faster than another? 
• What is happening during those additional minutes? 
• How much of that variation is actually avoidable?

But the study also raises a more consequential issue. Especially for patients receiving time-sensitive procedures, avoidable workflow delays do more than consume capacity. They can delay treatment and put timely patient care at risk.

Avoidable delays stemmed from phases outside of the procedure itself

Lower-extremity angiographies are common and relatively standardized vascular procedures. These are the kinds of cases you would expect to look fairly similar from one hospital to another.

But they don’t. Across the five hospitals, researchers found significant variation at nearly every stage of the perioperative workflow, even after accounting for differences in case and scheduling characteristics.

The variation was not limited to the active procedure. Median patient preparation ranged from 10 to 21 minutes, room cleanup from 12 to 32 minutes, and room setup from 27 to 38 minutes. 

Across hundreds of cases, those differences add up to meaningful OR capacity. And, unlike active procedure time, which may be driven by the clinical needs of the case, variation in these surrounding phases may be more amenable to operational improvement.

Variation that costs capacity can also delay care

Not every minute lost outside the procedure is simply a utilization problem. For some vascular patients, the stakes are higher than throughput.

Pre-procedural efficiency may be particularly important for patients with limb-threatening ischemia, for whom timely revascularization can help minimize tissue loss, promote wound healing, and preserve limb function.

For a patient who needs urgent intervention, avoidable time lost to waiting, interruptions, unclear handoffs, or other operational friction is not just an efficiency issue. It can mean a longer delay before treatment, creating additional risk for the patient.

Learn how Houston Methodist increased case volume by decreasing overtime.
Read the case study

Most OR metrics tell you that time was lost, not where it went

Leaders often suspect that variability exists. But they have far less visibility into why variability happens and what causes it. High-level metrics can show that performance varies, but not what is driving the difference.

Consider two hospitals in the study with nearly identical median case durations of about 146 minutes. Despite similar overall performance, their workflows looked very different. One site had a 40-minute median active procedure phase, compared with 53 minutes at the other, but the first spent roughly 16 minutes longer across patient preparation and room cleanup.

For perioperative leaders, that distinction matters. Total case duration alone could suggest the two sites perform similarly. But phase-level data shows exactly where time is being lost, whether in the procedure itself, patient preparation, or room cleanup — and gives leaders a clearer path to action.

Instead of applying broad interventions or assuming that one site’s practices will work at another, leaders can target the specific phase driving variation, preserve what is already working, and focus improvement efforts where they can have the greatest operational impact.

Making avoidable variation visible and preventable

For this study, Houston Methodist used Apella’s ambient computer vision platform to detect key OR events and break each case into distinct phases spanning preparation, the procedure itself, wrap-up, patient exit, cleaning, and room setup. This extra level of detail changes the question from “Why are cases longer at this hospital?” to “Where is the difference coming from?”

If a hospital looks slow overall, but the procedure itself is actually faster than average, teams can use these insights to stop focusing on the wrong part of the case. A phase level breakdown allows teams to identify if another site consistently gets through patient preparation more efficiently and examine what that team is doing differently. That especially matters in a multi-hospital system, where a better way of working may already exist at another site. 

Houston Methodist, for example, has already used this kind of phase-level analysis to inform a change in pre-procedural workflows, moving to a parallel model where anesthesia induction and patient preparation run simultaneously instead of in sequence, with team responsibilities split more clearly so anesthesia requests stop interrupting sterile preparation. 

Learn how Houston Methodist increased case volume by decreasing overtime.
Read the case study

Efficiency and care quality go hand-in-hand

Perioperative efficiency and patient care quality are often managed as separate priorities. This research is a reminder that they can be affected by the same underlying workflow.

Unnecessary waiting can reduce usable OR capacity. In a time-sensitive case, those same delays can also affect when treatment begins. An inconsistent handoff can put a room behind schedule and create added friction for the patient moving through care.

That is why understanding where time is being lost matters beyond efficiency. When perioperative teams can see and address avoidable variability, they can prevent unnecessary delays from becoming part of the patient’s care. Reducing that variability gives time back to the operating room. More importantly, it gives time back to patients.