James H. Abernathy

Realizing Improved Patient Care Through Human-Centered Operating Room Design: A Human Factors Methodology for Observing Flow Disruptions in the Cardiothoracic Operating Room

Background: Human factors engineering has allowed a systematic approach to the evaluation of adverse events in a multitude of high-stake industries. This study sought to develop an initial methodology for identifying and classifying flow disruptions in the cardiac operating room (OR). Methods: Two industrial engineers with expertise in human factors workflow disruptions observed 10 cardiac operations from the moment the patient entered the OR to the time they left for the intensive care unit. Each disruption was fully documented on an architectural layout of the OR suite and time-stamped during each phase of surgery (preoperative [before incision], operative [incision to skin closure], and postoperative [skin closure until the patient leaves the OR]) to synchronize flow disruptions between the two observers. These disruptions were then categorized. Results: The two observers made a total of 1,158 observations. After the elimination of duplicate observations, a total of 1,080 observations remained to be analyzed. These disruptions were distributed into six categories such as communication, usability, physical layout, environmental hazards, general interruptions, and equipment failures. They were further organized into 33 subcategories. The most common disruptions were related to OR layout and design (33%). Conclusions: By using the detailed architectural diagrams, the authors were able to clearly demonstrate for the first time the unique role that OR design and equipment layout has on the generation of physical layout flow disruptions. Most importantly, the authors have developed a robust taxonomy to describe the flow disruptions encountered in a cardiac OR, which can be used for future research and patient safety improvements.

Technologies in the wild (TiW): human factors implications for patient safety in the cardiovascular operating room

We describe different sources of hazards from cardiovascular operating room (CVOR) technologies, how hazards propagate in the CVOR and their impact on cognitive processes. Previous studies have examined hazards from poor design of a specific CVOR technology. However, the impact of different CVOR technologies functioning in context is not clearly understood. In addition, the impact of non-design hazards in technology devices is unclear. Our study identified hazards from organisational, physical/environmental elements, in addition to design of technology in a CVOR. We used observations, follow-up interviews and photographs. With qualitative analyses, we categorised the different hazard sources and their potential impact on cognitive processes. Patient safety can be built into technologies by incorporating user needs in design, decision-making and implementation of medical technologies. Practitioner summary: Effective design and implementation of technology in a safety-critical system requires prospective understanding of technology-related hazards. Our research fills this gap by studying different technologies in context of a CVOR using observations. Qualitative analyses identified different sources for technology-related hazards besides design, and their impact on cognitive processes.

Temporally and regionally disparate differences in plasmin activity by tranexamic acid.

BACKGROUND: A major complication associated with cardiac surgery is excessive and prolonged bleeding in the perioperative period. Improving coagulation by inhibiting fibrinolysis, primarily through inhibition of plasmin activity (PLact) with antifibrinolytics such as tranexamic acid (TXA), has been a pharmacological mainstay in cardiac surgical patients. Despite its almost ubiquitous use, the temporal and regional modulation of PLact profiles by TXA remains unexplored. Accordingly, we developed a fluorogenic-microdialysis system to measure in vivo dynamic changes in PLact after TXA administration in a large animal model. METHODS: Pigs (25–35 kg) were randomly assigned to receive TXA (30 mg/kg, diluted into 50 mL normal saline; n = 9) or vehicle (50 mL normal saline; n = 7). Microdialysis probes were placed in the liver, myocardium, kidney, and quadriceps muscle compartments. The microdialysate infusion contained a validated plasmin-specific fluorogenic peptide. The fluorescence emission (standard fluorogenic units [SFU]) of the interstitial fluid collected from the microdialysis probes, which directly reflects PLact, was determined at steady-state baseline and 30, 60, 90, and 120 min after TXA/vehicle infusion. Plasma PLact was determined at the same time points using the same fluorogenic substrate approach. RESULTS: TXA reduced plasma PLact at 30 min after infusion by >110 SFU compared with vehicle values (P < 0.05). Specifically, there was a decrease in liver PLact at 90 and 120 min after TXA infusion of >150 SFU (P < 0.05) and 175 SFU (P < 0.05), respectively. The decrease in liver PLact occurred 60 min after the maximal decrease in plasma PLact. In contrast, kidney, heart, and quadriceps PLact transiently increased followed by an overall decrease at 120 min. CONCLUSIONS: Using a large animal model and in vivo microdialysis measurements of PLact, the unique findings from this study were 2-fold. First, TXA induced temporally distinct PLact profiles within the plasma and selected interstitial compartments. Second, TXA caused region-specific changes in PLact profiles. These temporal and regional differences in the effects of TXA may have important therapeutic considerations when managing fibrinolysis in the perioperative period.

Management of LVAD Patients for Noncardiac Surgery: A Single-Institution Study

OBJECTIVE To describe the experience regarding the perioperative management of patients with left ventricular assist devices (LVADs) who require anesthesia while undergoing noncardiac surgery (NCS) at a single medical center. DESIGN Retrospective chart review SETTING Academic medical center PARTICIPANTS Patients with LVADs INTERVENTIONS Medical records from April 1, 2009 through January 31, 2014 were reviewed for patients who underwent Heartmate II LVAD placement at this facility. Individual records were reviewed for NCS after LVAD placement, specifically investigating perioperative and anesthetic management. MEASUREMENTS AND MAIN RESULTS Seventy-one patients underwent LVAD placement during this time period. Thirty-five patients (49%) underwent a total of 101 NCS procedures. Arterial catheters were placed in 19 patients (19%), and 33 patients (33%) were intubated for their procedure. No complications or perioperative mortality occurred related to the NCS. CONCLUSIONS Noncardiac surgery is becoming more common in patients with LVADs. Anesthetic management of these patients outside of the cardiac operating room is limited. Patients with Heartmate II LVADs can safely undergo noncardiac surgery.

Fast Left Prefrontal rTMS Reduces Post-Gastric Bypass Surgery Pain: Findings From a Large-Scale, Double-Blind, Sham-Controlled Clinical Trial

BACKGROUND A single session of left prefrontal rTMS has been shown to have analgesic effects, and to reduce post-operative morphine use. We sought to test these findings in a larger sample, and try and see if multiple sessions had additive analgesic benefit. METHODS 108 patients undergoing laparoscopic gastric bypass surgery received two sessions of 10 Hz rTMS (110% of motor threshold) over the left dorsolateral prefrontal cortex (one immediately following surgery and one 4 h later). Participants were randomly assigned to receive 2 sessions of real rTMS, 2 sessions of sham, 1 real then 1 sham, or 1 sham then 1 real rTMS treatments. Patients and study staff were blind to rTMS conditions. RESULTS Unlike previous rTMS trials for post-operative pain, no differences emerged between groups with respect to total patient-controlled analgesia usage (IV hydromorphone). However, despite no difference in IV analgesic usage, subjects that received 2 real rTMS sessions rated both the affective and sensory dimensions of their pain significantly lower than those in the sham–sham group at several time points during the post-surgical/post-rTMS period. CONCLUSIONS This study suggests that left prefrontal rTMS may produce significant analgesic effects in the perioperative setting. However, further work is needed to understand this effect and attempt to make it clinically useful in light of the lack of effect on PCA hydromorphone use.

Interstitial Plasmin Activity With Epsilon Aminocaproic Acid: Temporal and Regional Heterogeneity

BACKGROUND Epsilon aminocaproic acid (EACA) is used in cardiac surgery to modulate plasmin activity (PLact). The present study developed a fluorogenic-microdialysis system to measure in vivo region specific temporal changes in PLact after EACA administration. METHODS Pigs (25 to 35 kg) received EACA (75 mg/kg, n = 7) or saline in which microdialysis probes were placed in the liver, myocardium, kidney, and quadricep muscle. The microdialysate contained a plasmin-specific fluorogenic peptide and fluorescence emission, which directly reflected PLact, determined at baseline, 30, 60, 90, and 120 minutes after EACA/vehicle infusion. RESULTS Epsilon aminocaproic acid caused significant decreases in liver and quadricep PLact at 60, 90, 120 minutes, and at 30, 60, and 120 minutes, respectively (p < 0.05). In contrast, EACA induced significant biphasic changes in heart and kidney PLact profiles with initial increases followed by decreases at 90 and 120 minutes (p < 0.05). The peak EACA interstitial concentrations for all compartments occurred at 30 minutes after infusion, and were fivefold higher in the renal compartment and fourfold higher in the myocardium, when compared with the liver or muscle (p < 0.05). CONCLUSIONS Using a large animal model and in vivo microdialysis measurements of plasmin activity, the unique findings from this study were twofold. First, EACA induced temporally distinct plasmin activity profiles within the plasma and interstitial compartments. Second, EACA caused region-specific changes in plasmin activity profiles. These temporal and regional heterogeneic effects of EACA may have important therapeutic considerations when managing fibrinolysis in the perioperative period.

Anesthesia maintenance and vigilance: Examining task switching

Limited research has focused on vigilance during the maintenance phase of anesthesia work. The goal of this study was to identify anesthesia maintenance tasks and to identify the transitions between these tasks within the perspective of the vigilance paradigm. In this study, three bariatric surgeries were recorded and analyzed using a task categorization structure. Across the surgeries the primary anesthesia provider spent 71% of their time doing patient or display monitoring tasks. Task frequency and transition visualizations were generated to identify trends in the task switching. Transitions between the task categories occurred approximately once every nine seconds for the primary anesthesia provider. Additionally, it appears that regardless of the task, there was a high frequency of task transitions to looking at the visual displays and then from the visual displays towards the patient. The results of this study emphasize the importance of vigilance for anesthesia display design.

Focus: The society of cardiovascular anesthesiologists' initiative to improve quality and safety in the cardiovascular operating room

The Society of Cardiovascular Anesthesiologists (SCA) introduced the FOCUS initiative (Flawless Operative Cardiovascular Unified Systems) in 2005 in response to the need for a rigorous scientific approach to improve quality and safety in the cardiovascular operating room (CVOR). The goal of the project, which is supported by the SCA Foundation, is to identify hazards and develop evidence-based protocols to improve cardiac surgery safety. A hazard is anything that has the potential to cause a preventable adverse event. Specifically, the strategic plan of FOCUS includes 3 goals: (1) identifying hazards in the CVOR, (2) prioritizing hazards and developing risk-reduction interventions, and (3) disseminating these interventions. Collectively, the FOCUS initiative, through the work of several groups composed of members from different disciplines such as clinical medicine, human factors engineering, industrial psychology, and organizational sociology, has identified and documented significant hazards occurring daily in our CVORs. Some examples of frequent occurrences that contribute to reduce the safety and quality of care provided to cardiac surgery patients include deficiencies in teamwork, poor OR design, incompatible technologies, and failure to adhere to best practices. Several projects are currently under way that are aimed at better understanding these hazards and developing interventions to mitigate them. The SCA, through the FOCUS initiative, has begun this journey of science-driven improvement in quality and safety. There is a long and arduous road ahead, but one we need to continue to travel.

The effect of movement and cue complexity on tactile change detection

There is a growing interest in using touch to offload the often overburdened visual channel as its merit has been demonstrated in various work domains. However, more work is needed to understand the perceptual limitations of the tactile modality, including how it is affected by change blindness (i.e., failure to detect changes due to transients) as the majority of work on change blindness has been in vision. This study examines how movement and cue complexity affects the ability to detect tactile changes. The findings indicate the ability to detect changes are affected by: 1) movement (walking resulted in worse change detection rates compared to sitting) and 2) cue complexity (high complexity cues had worse change detection rates compared to low complexity). Overall, this work adds to the knowledge base of tactile perception and can inform the design of tactile displays for multiple work domains such as anesthesiology.

Epidural removal after perioperative myocardial infarction and coronary stent placement.

We report the case of a 77-year-old, 72.3-kg, white man with degenerative joint disease, anemia, thalassemia minor, and tobacco abuse but otherwise negative history and preoperative evaluation, who experienced an ST-segment elevation myocardial infarction (STEMI) after total hip arthroplasty with an indwelling epidural catheter. Written consent and an institutional review board exemption were obtained to report this case. On skin closure, ST-segment elevations developed and ventricular fibrillation soon followed. Advanced cardiovascular life support protocols restored sinus rhythm, and systemic anticoagulation was initiated (intravenous unfractionated heparin, rectal clopidogrel, and aspirin). On cardiac catheterization, multivessel disease was diagnosed and a bare metal stent was placed. The patient was transferred to the intensive care unit, intubated, and sedated. Based on platelet aggregometry that revealed 0% inhibition of platelets and normal coagulation studies, the epidural catheter was removed. The patient was extubated on postoperative day 1 and later discharged to a skilled nursing facility free of neurologic deficits. Neuraxial catheter removal in conjunction with thienopyridines carries the risk of spinal hematoma formation; however, dual antiplatelet therapy is a central component in the management of STEMI patients. Thienopyridine effects are time and dose dependent, with loading doses accelerating attainment of steady state. Platelet function testing may help determine the risk of thrombotic or hemorrhagic events while using antiplatelet therapy. The VerifyNow System (Accumetrics, Inc, San Diego, California) was used to investigate the effects of clopidogrel on our patient. Although the VerifyNow system lacks the sensitivity of “gold standard” conventional platelet aggregometry, it has been shown to provide significant correlation to platelet aggregometry in patients undergoing dual antiplatelet therapy. Given the emergent nature of the clinical dilemma presented, rapid point-ofcare information (VerifyNow) assisted in the clinical decision for neuraxial catheter removal. Three previous case reports have described similar situations, except medications were held until laboratory data normalized, resulting in 1 indwelling epidural catheter for 4 weeks. This case differs because it demonstrates that early assessment may permit epidural catheter removal without cessation of antiplatelet therapy.