Detection of sleep-disordered breathing with ambulatory Holter monitoring.

PURPOSE: Obstructive sleep apnea (OSA) syndrome is a common condition that can impact clinical outcomes among patients with cardiovascular disease. Screening all subjects with heart disease via polysomnography (PSG) is costly and resource-limited. We sought to compare a Holter monitor-based algorithm to detect OSA to in-laboratory polysomnography (PSG). METHODS: Prospective cohort study of patients undergoing in-laboratory attended PSG for the evaluation of OSA. A standard 12-lead Holter monitor was attached to patients at the initiation of PSG. Holter-derived respiratory disturbance index (HDRDI) was extracted from the respiratory myogram, based on detecting skeletal muscle "noise" detected on the baseline. Apneic and hypopneic episodes were identified by comparing sudden changes in the myogram to abrupt increases in heart rate. The HDRDI was compared with the PSG-derived apnea-hypopnea index (PDAHI). RESULTS: Thirty patients underwent simultaneous Holter monitoring and overnight diagnostic PSG. An ROC curve for peak HDRDI was 0.79 (95% CI 0.61, 0.97) for OSA, with sensitivity of 94.4% and specificity of 54.5%. A cutoff value of HDRDI < 10 appeared to identify those individuals without clinically significant sleep-disordered breathing. CONCLUSION: Holter-derived respiration detected OSA comparable to PSG. Further study is warranted to determine its utility for screening and diagnosing OSA in appropriately selected patients.

Assessing the interaction of respiration and heart rate in heart failure and controls using ambulatory Holter recordings.

Breathing is a critical component of cardiopulmonary function, but few tools exist to evaluate respiration in ambulatory patients. Holter monitoring allows accurate diagnosis of a host of cardiac issues, and several investigators have demonstrated the ability to detect respiratory effort on the electrocardiogram. In this study we introduce a myogram signal derived from 12-lead, high frequency Holter as a means of detecting respiratory effort. Using the combined myogram and ECG signal, four novel variables were created: total number of Cheyne-Stokes episodes; the BWRatio, the ratio of power (above baseline) measured one second after peak-to-peak respiratory power, an assessment of the "shape" of the respiratory effort; DRR, the change in RR interval centering around peak inspiration; and minutes of synchronized breathing, a fixed ratio of heart beats to respiratory cycles. These variables were assessed in 24-hour recordings from three cohorts: healthy volunteers (n=33), heart failure subjects from the GISSI HF trial (n=383), and subjects receiving implantable defibrillators with severely depressed left ventricular function enrolled in the M2Risk trial (n=470). We observed a statistically significant 6-fold increase in the number of Cheyne-Stokes episodes (p=0.01 by ANOVA), decreases in BWRatio (p<0.001), as well as decrease in DRR in heart failure subjects; only minutes of synchronized breathing was not significantly decreased in heart failure. This study provides "proof of concept" that novel variables incorporating Holter-derived respiration can distinguish healthy subjects from heart failure. The utility of these variables for predicting heart failure, arrhythmia, and death risk in prospective studies needs to be assessed.

Conflicts between ethics and law for military mental health providers.

Military mental health providers routinely experience mixed-agency ethical dilemmas when obligations to patients and the military conflict. Particularly difficult mixed-agency dilemmas occur when a military psychiatrist, psychologist, or social worker encounters an apparent conflict between an ethical obligation--enumerated in a professional code of ethics--and a federal statute. This article explores ethical-legal conflicts for uniformed mental health providers. Three case vignettes illustrate situations in which military providers may find themselves stuck between incongruent ethical and legal demands. The authors conclude with several recommendations designed to prevent and resolve ethical-legal conflicts for military mental health providers.

Automation of the I-PASS Tool to Improve Transitions of Care.

INTRODUCTION: Errors in communication during handoffs are a significant source of medical error and put patients at risk. The I-PASS system was designed to systematically communicate information to the oncoming healthcare provider and has been shown to decrease the risk of communication errors. The objective of this observational quality improvement study was to determine whether the addition of a partially automated, electronic handoff tool would further decrease errors in communication during transitions of care for inpatient medical teams. METHODS: We created an electronic tool to incorporate user-generated patient information in the I-PASS format with automatically compiled data derived from the electronic medical record. Numbers of errors in the printed handoff document were recorded before and after intervention. RESULTS: The first implementation cycle demonstrated an absolute risk reduction for written errors of 45.6% (95% confidence interval [CI] 39.2-51.2%) and a number needed to treat (NNT) of three patients. The second cycle showed an absolute risk reduction of 53.3% (95% CI 39.8-63.9%; NNT 2). Aggregate data showed an absolute risk reduction of 46.6% (95% CI 41.0-51.7%, NNT 3). CONCLUSIONS: Improving the routine task of patient handoff through the thoughtful application of technology can yield benefits in terms of decreasing documentation errors and streamlining workflow before patient handoff.

Severe Systemic Lead Toxicity Resulting From Extra-Articular Retained Shrapnel Presenting as Jaundice and Hepatitis: A Case Report and Review of the Literature.

INTRODUCTION: Despite greater than 60,000 nonfatal firearm injuries per year in the United States, retained shrapnel is a relatively rare cause of systemic lead toxicity with less than 100 cases reported in the medical literature since 1867. While intra-articular retained shrapnel as a cause of lead toxicity is well-described, extra-articular fragments are less well known to cause symptomatic disease. CASE REPORT: A 31-year-old man initially presented with abdominal pain, constipation, jaundice, and elevated liver transaminases approximately 3 weeks after suffering a left lower extremity injury during athletic activity. The patient was found to have steatohepatitis after extensive inpatient and outpatient gastroenterological workup to include upper and lower endoscopy, liver ultrasound, and biopsy of the liver to confirm the diagnosis. Imaging was incidentally notable for retained gunshot in the left flank and large shell fragment containing seroma in the left thigh. The patient was initially discharged with improved pain, but later presented to a primary care clinic with weight loss and continued pain. This was followed by a subsequent progression to diffuse weakness, ultimately resulting in an inability to ambulate. The patient was readmitted to a tertiary care medical center, 3 months after the initial presentation. Physical exam was then notable for 70-lb weight loss from initial admission and diffuse peripheral weakness with global muscle atrophy. Following a broad differential workup, he was found to have a blood lead level of 129 µg/dL, and hemoglobin of 7.7 g/dL with basophilic stippling on peripheral smear. The patient was transferred to the intensive care unit for chelation therapy with dimercaprol and calcium ethylenediaminetetraacetic acid. Lead levels initially decreased, but rose when patient was transitioned to oral therapy with succimer. Surgery was consulted for removal of multiple retained fragments, which were analyzed by the Joint Pathology Center and found to contain lead. The patient's motor function gradually improved on oral chelation and he was discharged to a subacute rehabilitation facility. CONCLUSION: This complex case describes a rare cause for a relatively common clinical presentation, jaundice and hepatitis, and reinforces the importance of longitudinal follow up and reassessment of a patient with an unknown illness and worsening clinical condition. Diagnosis of systemic lead toxicity is challenging because of its protean clinical manifestations, and relative rarity with the advent of strict environmental lead controls and decrease in lead-based paint and industrial products. Furthermore, extra-articular lead remains a rare cause of systemic toxicity, and the surgical standard of care has been to not remove these fragments in gunshot victims. This case adds to a small amount of evidence that lead screening may be of value in selected patients with extra-articular retained shrapnel, especially those with seroma and osteophyte formation in the wound.