David N. Mohr

Incidence of Venous Thromboembolism in Hospitalized Patients vs Community Residents

OBJECTIVE To estimate the incidence rates of deep venous thrombosis (DVT) and pulmonary embolism (PE) in hospitalized patients and to compare these with incidence rates in community residents. PATIENTS AND METHODS We performed a retrospective review of the complete medical records from a population-based inception cohort of patients who resided in Olmsted County, Minnesota, and had an incident DVT or PE from 1980 through 1990. RESULTS From 1980 through 1990, 911 Olmsted County residents experienced their first lifetime event of definite, probable, or possible venous thromboembolism. Of these residents, 253 had been hospitalized for some reason other than a diagnosis of DVT or PE (in-hospital cases), and 658 were not hospitalized at onset of venous thromboembolism (community residents). The average annual age- and sex-adjusted incidence of in-hospital venous thromboembolism was 960.5 (95% confidence interval, 795.1-1125.9) per 10,000 person-years and was more than 100 times greater than the incidence among community residents at 7.1 (95% confidence interval, 6.5-7.6) per 10,000 person-years. The incidence of venous thromboembolism rose markedly with increasing age for both groups, with PE accounting for most of the age-related increase among in-hospital cases. Incidence rates in the 2 groups changed little over time despite a reduction in the average length of hospital stay between 1980 and 1990. CONCLUSIONS Venous thromboembolism is a major national health problem, especially among elderly hospitalized patients. This finding emphasizes the need for accurate identification of hospitalized patients at risk for venous thromboembolism and a better understanding of the mechanisms involved so that safe and effective prophylaxis can be implemented.

Benign Positional Vertigo: Incidence and Prognosis in a Population-Based Study in Olmsted County, Minnesota

A retrospective review of our population-based medical records linkage system for residents of Olmsted County, Minnesota, revealed 53 patients (34 women and 19 men; mean age, 51 years) with newly diagnosed benign positional vertigo in 1984. The age- and sex-adjusted incidence was 64 per 100,000 population per year (95% confidence interval, 46 to 81 per 100,000). The incidence of benign positional vertigo increased by 38% with each decade of life (95% confidence interval, 23 to 54%). One patient had an initial stroke during follow-up; thus, the relative risk for new stroke associated with benign positional vertigo was 1.62 (95% confidence interval, 0.04 to 8.98) in comparison with the expected occurrence based on incidence rates for an age- and sex-adjusted control population. The observed survival among the 53 Olmsted County residents with benign positional vertigo diagnosed in 1984 was not significantly different from that of an age- and sex-matched general population. Patients with benign positional vertigo seem to have a good prognosis.

The Venous Stasis Syndrome After Deep Venous Thrombosis or Pulmonary Embolism: A Population-Based Study

OBJECTIVES To estimate the incidence and determine predictors of venous stasis syndrome and venous ulcers after deep venous thrombosis and pulmonary embolism. PATIENTS AND METHODS This population-based retrospective cohort study reviewed medical records of 1527 patients with incident deep venous thrombosis or pulmonary embolism between 1966 and 1990. We recorded baseline characteristics, event type (deep venous thrombosis with or without pulmonary embolism or pulmonary embolism alone), leg side and site of deep venous thrombosis (proximal with or without distal deep venous thrombosis vs distal deep venous thrombosis alone), and venous stasis syndrome and venous ulcer. RESULTS Two hundred forty-five patients developed venous stasis syndrome. One-year, 5-year, 10-year, and 20-year cumulative incidence rates were 7.3%, 14.3%, 19.7%, and 26.8%, respectively. By 20 years the cumulative incidence of venous ulcers was 3.7%. Patients with deep venous thrombosis with or without pulmonary embolism were 2.4-fold (95% confidence interval, 1.7-fold-3.2-fold) more likely to develop venous stasis syndrome than patients with pulmonary embolism and no diagnosed deep venous thrombosis. In patients aged 40 years or younger with proximal compared with distal-only deep venous thrombosis, venous stasis syndrome was 3.0-fold more likely (95% confidence interval, 1.6-fold-4.7-fold). In patients with unilateral leg deep venous thrombosis, venous stasis syndrome usually developed in the concordant leg (P < .001). There was a 30% (95% confidence interval, 2%-62%) increased risk for venous ulcer per decade of age at the incident venous thromboembolism. CONCLUSIONS The cumulative incidence of venous stasis syndrome continues to increase for 20 years after venous thromboembolism. Pulmonary embolism alone is less likely to cause venous stasis syndrome.

The Enterprise Data Trust at Mayo Clinic: A semantically integrated warehouse of biomedical data

Mayo Clinics Enterprise Data Trust is a collection of data from patient care, education, research, and administrative transactional systems, organized to support information retrieval, business intelligence, and high-level decision making. Structurally it is a top-down, subject-oriented, integrated, time-variant, and non-volatile collection of data in support of Mayo Clinics analytic and decision-making processes. It is an interconnected piece of Mayo Clinics Enterprise Information Management initiative, which also includes Data Governance, Enterprise Data Modeling, the Enterprise Vocabulary System, and Metadata Management. These resources enable unprecedented organization of enterprise information about patient, genomic, and research data. While facile access for cohort definition or aggregate retrieval is supported, a high level of security, retrieval audit, and user authentication ensures privacy, confidentiality, and respect for the trust imparted by our patients for the respectful use of information about their conditions.

The Canalith Repositioning Procedure for the Treatment of Benign Paroxysmal Positional Vertigo: A Randomized Controlled Trial

OBJECTIVE To compare the canalith repositioning procedure (CRP) with a sham maneuver for the treatment of benign paroxysmal positional vertigo. PATIENTS AND METHODS We recruited 50 patients with a history of positional vertigo and unilateral positional nystagmus on physical examination (Dix-Hallpike maneuver). Patients were randomized to either the CRP (n = 24) or a sham maneuver (n = 26). Measured outcomes included resolution of vertigo and positional nystagmus at follow-up examination. RESULTS The mean duration of follow-up was 10 days for both groups. Resolution of symptoms was reported by 12 (50%) of the 24 patients in the CRP group and by 5 (19%) of the 26 patients in the sham group (P = .02). The results of the Dix-Hallpike maneuver were negative for positional nystagmus in 16 (67%) of 24 patients in the CRP group and in 10 (38%) of 26 patients in the sham group (P = .046). CONCLUSION The CRP is effective treatment of benign paroxysmal positional vertigo, and this procedure can be performed by general internists on outpatients with this disorder.

Venous Thromboembolism Associated With Hip and Knee Arthroplasty: Current Prophylactic Practices and Outcomes

Joint registry and hospital data bases for 5,024 total hip and total knee arthroplasties done between 1986 and 1988 at the Mayo Clinic were used to study prophylactic measures and frequency of symptomatic deep venous thrombosis and pulmonary embolism. In virtually all patients, graduated compression stockings were used, with or without another type of prophylaxis. Only 44 of 3,115 patients who underwent hip arthroplasty (1.4%) and 32 of 1,909 patients who underwent knee arthroplasty (1.7%) had definite or probable deep venous thrombosis or pulmonary embolism. Death definitely or possibly attributable to pulmonary embolism occurred in 11 patients who underwent hip arthroplasty (0.35%) and 1 patient who underwent knee arthroplasty (0.05%). Although patients with a history of deep venous thrombosis or pulmonary embolism were more likely to receive warfarin than were patients without such a history, the relative risk of symptomatic deep venous thrombosis or pulmonary embolism in patients who underwent hip arthroplasty and received warfarin postoperatively was approximately half that in patients who received other types of prophylaxis. The risk of death from pulmonary embolism was similarly diminished in the group that received warfarin. The lower rates of these complications in the patients who received warfarin support the prophylactic use of this agent after total hip arthroplasty.

Estimation of Surgical Risk in the Elderly: A Correlative Review

Age continues to be a risk factor for overall mortality in elective and emergency surgical procedures. Postoperative pneumonias, life‐threatening cardiac complications, and malignancy‐related complications account for most deaths. Heart disease, dementia, and diabetes confer an additional surgical risk for elderly patients. Careful preoperative assessment, however, can categorize elderly patients into groups that are at no additional risk. Factors other than age should be considered in estimating surgical risk in the elderly.

Speech recognition as a transcription aid: a randomized comparison with standard transcription.

OBJECTIVE Speech recognition promises to reduce information entry costs for clinical information systems. It is most likely to be accepted across an organization if physicians can dictate without concerning themselves with real-time recognition and editing; assistants can then edit and process the computer-generated document. Our objective was to evaluate the use of speech-recognition technology in a randomized controlled trial using our institutional infrastructure. DESIGN Clinical note dictation from physicians in two specialty divisions was randomized to either a standard transcription process or a speech-recognition process. Secretaries and transcriptionists also were assigned randomly to each of these processes. MEASUREMENTS The duration of each dictation was measured. The amount of time spent processing a dictation to yield a finished document also was measured. Secretarial and transcriptionist productivity, defined as hours of secretary work per minute of dictation processed, was determined for speech recognition and standard transcription. RESULTS Secretaries in the endocrinology division were 87.3% (confidence interval, 83.3%, 92.3%) as productive with the speech-recognition technology as implemented in this study as they were using standard transcription. Psychiatry transcriptionists and secretaries were similarly less productive. Author, secretary, and type of clinical note were significant (p < 0.05) predictors of productivity. CONCLUSION When implemented in an organization with an existing document-processing infrastructure (which included training and interfaces of the speech-recognition editor with the existing document entry application), speech recognition did not improve the productivity of secretaries or transcriptionists.

Methemoglobinemia From Topically Applied Anesthetic Spray

Topically applied anesthetic spray is commonly used as part of premedication for general anesthesia and for endoscopic procedures; it is rarely associated with side effects. In this report, we describe two cases of toxic methemoglobinemia that resulted from topically applied anesthetic spray used before endoscopy. In both cases, standard doses were used; however, methemoglobin levels of 45% and 38% developed within 1 hour of the procedure. Both patients had normal levels of erythrocyte methemoglobin reductase, an indication that this rare but potentially fatal side effect can occur in persons who have no predisposing factors. Because toxic methemoglobinemia is easily treated, our report emphasizes the need to recognize this problem when topically applied anesthetic sprays are used.

Isolated asymptomatic microhematuria: A cross-sectional analysis of test-positive and test negative patients.

The relationship of asymptomatic microhematuria to urologic disease in a general population was studied by using population-based data resources in Rochester, Minnesota, to identify 635 patients with isolated asymptomatic microhematuria (AMs) and 635 controls. Prevalences of minor urologic diseases were 41.8% in those with positive tests (AMs) and 36.9% in controls (p>0.05). Moderately serious urologic diseases were found in 16.7% of AMs and 9.2% of controls (p=0.006); significant differences were found only for renal calculi and various causes of increased serum creatinine. Urologic cancers were found in 1.2% of AMs and 0.2% of controls (p=0.04), but only prostatic carcinoma was found in a significantly higher percentage of those with positive tests (p=0.047). Urologic cancers were found in 3.6% of test-positive patients with >8 RBC/high-power field vs. 0.5% of those with 1–8 RBC/high-power field and 0.2% of controls (p>0.05). The predictive value of low-grade isolated asymptomatic microhematuria is too low to be of value in screening for urologic cancers in unselected patients, and only certain moderately serious urologic diseases and prostatic cancer were more frequent in patients who had asymptomatic microhematuria than in controls.