Number and size-spectra of myelinated nerve fibers of human premolars

Summary The primary objective of this study was to determine the number and size of myelinated nerve fibers at the subcervical, midroot and juxta-apical levels of human premolars. Sixty-seven healthy premolars extracted from adolescents were utilized. Root-discs were prepared from the three sites and processed for light and electron microscopy. The myelinated nerve fibers were counted from semithin sections using a sampling microscope. The measurements were taken from composite electron micrographs using an electronic image processing unit. A total of 1883 myelinated axons from seven mandibular second premolars was gauged. The 67 teeth had an average of 312±149 myelinated nerve fibers at the juxta-apical level (range 18 to 728). The contra- and ipsilateral differences in means among the four groups of premolars were not significant (P>0.05). The number of nerves increased significantly (P<0.05) toward midroot and subcervical (P<0.001) levels in all groups. The average neural diameter was 3.51.0 m at the juxta-apical level, and the between-teeth difference in mean was found to be significant (P<0.01). There was no decline (P>0.05) in the diameter of myelinated nerve fibers toward midroot and subcervical levels.     

Analysis of terminal events in 109 successive deaths in a Belgian intensive care unit

Objective To determine the incidence of end-of-life decisions in intensive care unit (ICU) patients.Design and setting Prospective data collection and questionnaire in a 31-bed medicosurgical ICU in a university hospital.Patients and participants All 109 ICU patients who died during a 3-month period (April–June 2001). Members of the ICU team were also invited to complete a questionnaire regarding the circumstances of each patients death. Cardiopulmonary resuscitation was performed in 21 of the patients; other mechanisms leading to death were brain death (n=19), refractory shock (n=17), and refractory hypoxemia (n=2). The decision was taken in the remaining 50 patients to withdraw (n=43) or withhold (n=7) therapy. Questionnaires were completed for 68 patients, by physician and nurse in 40 cases, physician only in 20 cases, and nurse only in 8 cases. Questionnaires were obtained for 34 of 50 patients for whom a decision was made to limit therapy.Results Respondents generally felt that the decision was timely (n=28, 82%), 5 (15%) felt the decision was too late, and one (3%) that the decision was made too soon, before the family could be informed.Conclusions Therapeutic limitations are frequent in patients dying in the ICU, with withdrawing more common than withholding life support. Generally members of the ICU staff were satisfied with the end-of-life decisions made.     

The indications and applications of interscalene brachial plexus block for surgery about the shoulder

Due to increasing use of interscalene brachial plexus block (ISBPB) for surgery about the shoulder, it was our purpose to review the indications, techniques, complications, and most recent advances of interscalene brachial plexus block. All MEDLINE publications regarding interscalene and brachial plexus block from July 1966 to July 2003 were reviewed, analyzed and scrutinized. ISBPB provides surgical anesthesia and perioperative analgesia for procedures involving dermatomes C5 through C7. ISBPB is reliably performed with very high success (≥94% effectiveness) and few major complications (≤0.4%). Recent advances in ISBPB techniques, including perineural catheters for patient-controlled interscalene analgesia, afford superior postoperative pain relief, early rehabilitation, and excellent patient satisfaction. When performed by trained personnel, ISBPB is a safe and effective regional anesthetic technique with rapidly developing applications aimed to improve postoperative analgesia following surgery of the proximal upper limb.     

Diagnostic accuracy of multidetector computed tomography coronary angiography in patients with angiographically proven coronary artery disease

OBJECTIVES: The aim of the present study was to evaluate the diagnostic accuracy in detecting high-grade coronary stenoses in patients with known coronary artery disease (CAD) using multidetector computed tomography (MDCT). BACKGROUND: The MDCT systems with electrocardiographic (ECG)-gating permit visualization of the coronary arteries. However, severe calcifications and higher heart rates are known to degrade image quality and limit correct diagnosis. METHODS: Sixty-six patients with proven CAD as assessed by conventional coronary angiography (CCA) were studied by MDCT (mean time 24 months postangiography). Total calcium score and all coronary arteries, including distal segments and side branches, were assessed with respect to evaluability, presence of high-grade coronary artery stenoses (>70%), and correct diagnosis. Results were compared to CCA. RESULTS: A total of 105 lesions were detected by CCA. The MDCT correctly detected 39 lesions (sensitivity 37%, specificity 99%). The correct clinical diagnosis could be obtained in 24 patients (36%). Artifacts due to elevated heart rates or severe coronary artery calcification were the main cause of degraded image quality inhibiting correct diagnosis. In 21/66 patients (32%) all four major coronary vessel segments could be visualized. A threshold for maximum heart rate and a maximum calcification level were established (65 beats/min and an Agatston Score Equivalent of 335, respectively). A second analysis was made using these thresholds. Of all patients studied, 10/11 (91%) were correctly diagnosed when adhering to these thresholds. CONCLUSIONS: When using MDCT as a noninvasive diagnostic modality to assess advanced CAD, it appears to be mandatory to preselect patients in order to achieve reliable results.     

Predicting Delirium Risk Using an Automated Mayo Delirium Prediction Tool: Development and Validation of a Risk-Stratification Model

ObjectiveTo develop a delirium risk-prediction tool that is applicable across different clinical patient populations and can predict the risk of delirium at admission to hospital.MethodsThis retrospective study included 120,764 patients admitted to Mayo Clinic between January 1, 2012, and December 31, 2017, with age 50 and greater. The study group was randomized into a derivation cohort (n=80,000) and a validation cohort (n=40,764). Different risk factors were extracted and analyzed using least absolute shrinkage and selection operator (LASSO) penalized logistic regression.ResultsThe area under the receiver operating characteristic curve (AUROC) for Mayo Delirium Prediction (MDP) tool using derivation cohort was 0.85 (95% confidence interval [CI], .846 to .855). Using the regression coefficients obtained from the derivation cohort, predicted probability of delirium was calculated for each patient in the validation cohort. For the validation cohort, AUROC was 0.84 (95% CI, .834 to .847). Patients were classified into 1 of the 3 risk groups, based on their predicted probability of delirium: low (≤5%), moderate (6% to 29%), and high (≥30%). In the derivation cohort, observed incidence of delirium was 1.7%, 12.8%, and 44.8% (low, moderate, and high risk, respectively), which is similar to the incidence rates in the validation cohort of 1.9%, 12.7%, and 46.3%.ConclusionThe Mayo Delirium Prediction tool was developed from a large heterogeneous patient population with good validation results and appears to be a reliable automated tool for delirium risk prediction with hospitalization. Further prospective validation studies are required.