Desmond A. Jordan

Workflow modeling in critical care: Piecing together your own puzzle

The intensive care unit (ICU) is an instance of a very dynamic health care setting where critically ill patients are being managed. To provide good care, an extensive and coordinated communication amongst the role players, use of numerous information systems and operation of devices for monitoring and treatment purposes are required. The purpose of this research is to study error evolution and management within this environment. The focus is on representing the workflow of critical care environment, which emphasizes the importance such a representation may play in strategizing the management of medical errors. We used ethnographic observation and interview data to build individual pieces of the workflow, dependent on the individual and the activity concerned. Key personnel were intensively followed during their respective patient care activities and the related actions. All interactions were recorded for analysis. These clinicians and nurses were interviewed to complement the observation data and to delineate their individual workflows. These pieces of the ICU workflow were used to develop a generalize-able cognitive model to represent the intricate workflow applicable to other health care settings. The proposed model can be used to identify and characterize medical errors and for error prediction in practice.

Noncardiac surgery in long-term implantable left ventricular assist-device recipients

ObjectiveThe authors describe their experience with left ventricular assist-device (LVAD) recipients undergoing noncardiac surgery and delineate surgical, anesthetic, and logistic factors important in the successful intraoperative management of these patients. Summary Background DataLeft ventricular assist-devices have become part of the armamentarium in the treatment of end-stage heart failure. As the numbers of patients chronically supported with long-term implantable devices grows, general surgical problems that are commonly seen in other hospitalized patients are becoming manifest. Of particular interest is the intraoperative management of patients undergoing elective noncardiac surgical procedures. MethodsThe anesthesia records and clinical charts were reviewed for eight ventricular assist-device recipients undergoing general surgical procedures between August 1, 1990 and August 31, 1994. ResultsA total of 12 procedures were performed in 6 men and 2 women averaging 52.7 years of age. Mean time elapsed from device implantation to operation was 68 ± 35 days. Conventional inhalational and intravenous anesthetic techniques were well tolerated in these patients undergoing diverse surgical procedures. No perioperative mortality was observed. Five of eight patients went on to successful cardiac transplantation. ConclusionsHemodynamic recovery after LVAD insertion has defined a new group of patients who develop noncardiac surgical problems often seen in other critically ill patients. Recognition of the unique potential problems that the LVAD recipient may encounter in the perioperative period—in particular patient positioning, device limitations, and fluid and inotropic management—will ensure an optimal surged outcome for LVAD recipients undergoing noncardiac surgery.

PERSIVAL, a system for personalized search and summarization over multimedia healthcare information

In healthcare settings, patients need access to online information tha t can help them understand their medical situation. Physicians need information that is clinically relevant to an individual patient. In this paper, we present our progress on developing a system, PERSIVAL, that is designed to provide personalized access to a distributed patient care digital library. Using the secure, online patient records at New York Presbyterian Hospital as a user model, PERSIVALs components tailor search, presentation and summarization of online multimedia information to both patients and healthcare providers.

Intraoperative cardiac arrests in adults undergoing noncardiac surgery: incidence, risk factors, and survival outcome.

Background:Intraoperative cardiac arrest (ICA) is a rare but potentially catastrophic event. There is a paucity of recent epidemiological data on the incidence and risk factors for ICA. The objective of this study was to assess the incidence, risk factors, and survival outcome of ICAs in adults undergoing noncardiac surgery. Methods:The authors analyzed prospectively collected data for all noncardiac cases in the American College of Surgeons National Surgical Quality Improvement Program database from the years 2005 to 2007 (n = 362,767). Results:The incidence of ICA was 7.22 per 10,000 surgeries. After adjustment for American Society of Anesthesiologists physical status and other covariates, the odds of ICA increased progressively with the amount of transfusion (adjusted odds ratios = 2.51, 7.59, 11.40, and 29.68 for those receiving 1–3, 4–6, 7–9, and ≥ 10 units of erythrocytes, respectively). Other significant risk factors for ICA were emergency surgery (adjusted odds ratio = 2.04, 95% CI = 1.45–2.86) and being functionally dependent presurgery (adjusted odds ratio = 2.33, 95% CI = 1.69–3.22). Of the 262 patients with ICA, 116 (44.3%) died within 24 h, and 164 (62.6%) died within 30 days. Conclusions:Intraoperative blood loss as indicated by the amount of transfusion was the most important predictor of ICA. The urgency of surgery and the preoperative composite indicators of health such as American Society of Anesthesiologists status and functional status were other important risk factors. The high case fatality suggests that primary prevention might be the key to reducing mortality from ICA.

Language Generation for Multimedia Healthcare Briefings

This paper identifies issues for language generation that arose in developing a multimedia interface to healthcare data that includes coordinated speech, text and graphics. In order to produce brief speech for time-pressured caregivers, the system both combines related information into a single sentence and uses abbreviated references in speech when an unambiguous textual reference is also used. Finally, due to the temporal nature of the speech, the language generation module needs to communicate information about the ordering and duration of references to other temporal media, such as graphics, in order to allow for coordination between media.

Insights into the increased oxygen demand during chest physiotherapy

OBJECTIVES To determine the mechanism responsible for the increase in oxygen consumption (VO2) during chest physical therapy. Specifically, to examine the hypothesis that muscular activity is the major contributor to the increase in oxygen demand. DESIGN Prospective, observational study. SETTING University hospital surgical intensive care unit. PATIENTS Phase one included 13 patients who were mechanically ventilated after coronary artery bypass surgery. Phase two involved seven mechanically ventilated patients who had undergone major vascular or abdominal surgery. INTERVENTIONS Phase one involved turning patients to the lateral decubitus position. During the second phase, patients were given midazolam (0.15 microg/kg) 2 mins before an initial chest physiotherapy session and midazolam plus vecuronium (0.7 mg/kg) before a subsequent session. Physiologic measurements were made during the resting periods before and following each session, as well as at the completion of the intervention. MEASUREMENTS AND MAIN RESULTS Turning patients to the lateral position resulted in significant increases in oxygen uptake and CO2 elimination (VCO2). VO2 increased from 219 +/- 21 (SD) mL/min at rest to 324 +/- 58 mL/min (p <.05) with turning. These increases in oxygen demand were met by increases in both oxygen delivery (852 +/- 238 mL/min at rest to 1116 +/- 430 mL/min, p < .05) and extraction (0.27 +/- 0.7 at rest to 0.32 +/- 0.09, p < .05). There were associated increases in hemodynamic and respiratory variables including heart rate and systolic blood pressure. The administration of vecuronium completely suppressed the 50% increases in VO2 and VCO2 seen without the use of a muscle relaxant. The increases in systolic blood pressure were unaffected by vecuronium. The magnitude of the increase in PaCO2 (32 +/- 5 torr [4.3 +/- 0.7 kPa] at rest to 36 +/- 5 torr [4.8 +/- 0.7 kPa] during therapy, p < .05), was not accentuated by vecuronium (30 +/- 4 torr [4.0 +/- 0.5 kPa] to 35 +/- 6 torr [4.7 +/- 0.8 kPa], p < .05) despite a lack of any increase in minute ventilation or respiratory rate. This change was due to the parallel suppression of VCO2. CONCLUSIONS The increase in metabolic demand during chest physiotherapy is the result of increased muscular activity as evidenced by the suppression of VO2 following the administration of the muscle relaxant and the observation that turning a patient into the lateral decubitus position produces similar increases in VO2. The increases in blood pressure and cardiac output are due to another mechanism, most likely enhanced sympathetic output. The increase in physiologic activity produced by chest physiotherapy is thus secondary to both exercise-like and stress-like responses.

Long-term mortality of coronary artery bypass graft surgery and stenting with drug-eluting stents.

BACKGROUND Few studies have examined differences in long-term mortality between coronary artery bypass graft surgery and stenting with drug-eluting stents (DES) for multivessel disease without left main coronary artery stenosis. This study compares the risks of long-term mortality between these 2 procedures during a follow-up of up to 5 years. METHODS Patients who underwent isolated bypass surgery (n=13,212) and stenting with DES (n=20,161) between October 2003 and December 2005 in New York State were followed for their vital status through 2008. To control for treatment selection bias, bypass and stenting patients were matched on age, number of diseased coronary vessels, presence of proximal or nonproximal left anterior descending (LAD) artery disease, and propensity of undergoing bypass surgery. Five-year survival rates for the 2 procedures were compared and hazard ratios for death of bypass surgery compared with stenting were obtained. RESULTS The respective 5-year survival rates in the 8,121 pairs of matched bypass and stenting patients were 80.4% and 73.6% (p<0.001), and the risk of death after bypass surgery was 29% lower than for stenting (hazard ratio = 0.71, 95% confidence interval: 0.67 to 0.77, p<0.001). Significantly lower risks of death for bypass surgery were observed in patients with LAD artery disease but not in patients without LAD artery disease. Significantly lower risks of death for bypass surgery were also found in all patient subgroups defined by the presence of selected baseline risk factors. CONCLUSIONS Bypass surgery is associated with lower risk of death than stenting with DES for multivessel disease without left main stenosis.

Facilitating physicians' access to information via tailored text summarization.

We have developed a summarization system, TAS (Technical Article Summarizer), which, when provided with a patient record and journal articles returned by a search, automatically generates a summary that is tailored to the patient characteristics. We hypothesize that a personalized summary will allow a physician to more quickly find information relevant to patient care. In this paper, we present a user study in which subjects carried out a task under three different conditions: using search results only, using a generic summary and search results, and using a personalized summary with search results. Our study demonstrates that subjects do a better job on task completion with the personalized summary, and show a higher level of satisfaction, than under other conditions.

Thirty-Day Readmissions After Transcatheter Aortic Valve Implantation Versus Surgical Aortic Valve Replacement in Patients With Severe Aortic Stenosis in New York State

Background—Several studies have compared short-term and medium-term mortality rates for patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR), but no studies have compared short-term readmission rates for the 2 procedures. Methods and Results—New York’s Cardiac Surgery Reporting System was used to propensity match 617 TAVI and 1981 SAVR patients using numerous patient risk factors contained in the registry. The 389 propensity-matched pairs were then used to analyze differences in readmission rates between the 2 groups. TAVI and SAVR readmission rates were also compared for patients with a history of congestive heart failure and for patients aged ≥80. Also, reasons for readmission for TAVI and SAVR patients were examined and compared. Readmission rates were not statistically different for all propensity-matched TAVI and SAVR patients (respective rates, 18.8% and 19.3%; P=0.86). After further adjustment using a logistic regression model, there was still no significant difference (adjusted odds ratio, 0.97; 95% confidence interval [0.68–1.39]). For patients aged ≥80, the 30-day readmission rates were 19.9% and 22.0% (P=0.59), and when further adjusted using the logistic regression model, adjusted odds ratio=0.89 (0.55–1.45). For patients with a history of congestive heart failure, the respective rates were 22.8% and 20.4% (P=0.56), and with further adjustment, adjusted odds ratio became 1.15 (0.72–1.82). Conclusions—There are no statistically significant differences between TAVI and SAVR patients in short-term readmission rates.

Long-Term Mortality of Coronary Artery Bypass Grafting and Bare-Metal Stenting

BACKGROUND There is little information on relative survival with follow-up longer than 5 years in patients undergoing coronary artery bypass grafting (CABG) and patients undergoing percutaneous coronary intervention (PCI) with stenting. This study tested the hypothesis that CABG is associated with a lower risk of long-term (8-year) mortality than is stenting with bare-metal stents for multivessel coronary disease. METHODS We identified 18,359 patients with multivessel disease who underwent isolated CABG and 13,377 patients who received bare-metal stenting in 1999 to 2000 in New York and followed their vital status through 2007 using the National Death Index (NDI). We matched CABG and stent patients on the number of diseased coronary vessels, proximal left anterior descending (LAD) artery disease, and propensity of undergoing CABG based on numerous patient characteristics and compared survival after the 2 procedures. RESULTS In the 7,235 pairs of matched patients, the overall 8-year survival rates were 78.0% for CABG and 71.2% for stenting (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.64 to 0.74; p < 0.001). For anatomic groups classified by the number of diseased vessels and proximal LAD involvement, the HRs ranged from 0.53 (p < 0.001) for patients with 3-vessel disease involving proximal LAD artery disease to 0.78 (p = 0.05) for patients with 2-vessel disease but no disease in the LAD artery. A lower risk of death after CABG was observed in all subgroups stratified by a number of baseline risk factors. CONCLUSIONS Coronary artery bypass grafting is associated with a lower risk of death than is stenting with bare metal stents for multivessel coronary disease.