Reducing door-to-needle times using Toyota's lean manufacturing principles and value stream analysis

Abstract

Background and purpose: Earlier tissue-type plasminogen activator (tPA) treatment for acute ischemic stroke increases efficacy, prompting national efforts to reduce door-to-needle times. We used lean process improvement methodology to develop a streamlined intravenous tPA protocol.

Methods: In early 2011, a multidisciplinary team analyzed the steps required to treat patients with acute ischemic stroke with intravenous tPA using value stream analysis (VSA). We directly compared the tPA-treated patients in the "pre-VSA" epoch with the "post-VSA" epoch with regard to baseline characteristics, protocol metrics, and clinical outcomes.

Results: The VSA revealed several tPA protocol inefficiencies: routing of patients to room, then to CT, then back to the room; serial processing of workflow; and delays in waiting for laboratory results. On March 1, 2011, a new protocol incorporated changes to minimize delays: routing patients directly to head CT before the patient room, using parallel process workflow, and implementing point-of-care laboratories. In the pre and post-VSA epochs, 132 and 87 patients were treated with intravenous tPA, respectively. Compared with pre-VSA, door-to-needle times and percent of patients treated ≤60 minutes from hospital arrival were improved in the post-VSA epoch: 60 minutes versus 39 minutes (P<0.0001) and 52% versus 78% (P<0.0001), respectively, with no change in symptomatic hemorrhage rate.

Conclusions: Lean process improvement methodology can expedite time-dependent stroke care without compromising safety.

Figure. Acute stroke protocol pre-VSA (A) and post-VSA (B)

∞ EMS pre-notified the ED triage nurse of the patient’s arrival so that treating physicians and staff were waiting and ready to evaluate the patient immediately upon arrival. The patient could not be pre-registered and prior medical records could not be investigated prior to patient arrival as EMS was not allowed to give patient identifiers via radio due to violation of patient privacy. † Serial tasks were changed to In-parallel. * Head CT moved to first step in the protocol. # Transport from CT to trauma bay might be considered “time-wasteful”; however, three reasons prevented utilizing the CT scanner as the location for tPA delivery: (1) given the ED traffic and the demand for CT utilization, it was necessary to permit its use for other disease categories (such as trauma and others); (2) transport from CT scanner to trauma bay is about 30 seconds; and (3) the space and lighting for patient evaluation in the trauma bay are superior to that in the CT scanner room. § Point-of-Care INR sent (useful for patients suspected or known to be taking coumadin/warfarin). + Calling the Chief Resident might be considered “time-wasteful”; however, we ultimately decided that it “added value” by ensuring tPA administration was supervised by experienced physicians, ensuring safe and appropriate tPA delivery. VSA=Value Stream Analysis; Neuro MD=neurology medical doctor; Hx=history; NIHSS=National Institutes of Health Stroke Scale; RN=registered nurse; Tech=patient care technician.