Avoidance of Nitrous Oxide for Patients Undergoing Major Surgery: A Randomized Controlled Trial

Background: Nitrous oxide is widely used in anesthesia, often administered at an inspired concentration around 70%. Although nitrous oxide interferes with vitamin B12, folate metabolism, and deoxyribonucleic acid synthesis and prevents the use of high inspired oxygen concentrations, the consequences of these effects are unclear.

Methods: Patients having major surgery expected to last at least 2 h were randomly assigned to nitrous oxide-free (80% oxygen, 20% nitrogen) or nitrous oxide-based (70% N2O, 30% oxygen) anesthesia. Patients and observers were blind to group identity. The primary endpoint was duration of hospital stay. Secondary endpoints included duration of intensive care stay and postoperative complications; the latter included severe nausea and vomiting, and the following major complications: pneumonia, pneumothorax, pulmonary embolism, wound infection, myocardial infarction, venous thromboembolism, stroke, awareness, and death within 30 days of surgery.

Results: Of 3,187 eligible patients, 2,050 consenting patients were recruited. Patients in the nitrous oxide-free group had significantly lower rates of major complications (odds ratio, 0.71; 95% confidence interval, 0.56-0.89; P = 0.003) and severe nausea and vomiting (odds ratio, 0.40; 95% confidence interval, 0.31-0.51; P < 0.001), but median duration of hospital stay did not differ substantially between groups (7.0 vs. 7.1 days; P = 0.06). Among patients admitted to the intensive care unit postoperatively, those in the nitrous oxide-free group were more likely to be discharged from the unit on any given day than those in the nitrous oxide group (hazard ratio, 1.35; 95% confidence interval, 1.05-1.73; P = 0.02).     

Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS): Process, format, and clinimetric testing plan.

This article presents the revision process, major innovations, and clinimetric testing program for the Movement Disorder Society (MDS)-sponsored revision of the Unified Parkinson's Disease Rating Scale (UPDRS), known as the MDS-UPDRS. The UPDRS is the most widely used scale for the clinical study of Parkinson's disease (PD). The MDS previously organized a critique of the UPDRS, which cited many strengths, but recommended revision of the scale to accommodate new advances and to resolve problematic areas. An MDS-UPDRS committee prepared the revision using the recommendations of the published critique of the scale. Subcommittees developed new material that was reviewed by the entire committee. A 1-day face-to-face committee meeting was organized to resolve areas of debate and to arrive at a working draft ready for clinimetric testing. The MDS-UPDRS retains the UPDRS structure of four parts with a total summed score, but the parts have been modified to provide a section that integrates nonmotor elements of PD: I, Nonmotor Experiences of Daily Living; II, Motor Experiences of Daily Living; III, Motor Examination; and IV, Motor Complications. All items have five response options with uniform anchors of 0 = normal, 1 = slight, 2 = mild, 3 = moderate, and 4 = severe. Several questions in Part I and all of Part II are written as a patient/caregiver questionnaire, so that the total rater time should remain approximately 30 minutes. Detailed instructions for testing and data acquisition accompany the MDS-UPDRS in order to increase uniform usage. Multiple language editions are planned. A three-part clinimetric program will provide testing of reliability, validity, and responsiveness to interventions. Although the MDS-UPDRS will not be published until it has successfully passed clinimetric testing, explanation of the process, key changes, and clinimetric programs allow clinicians and researchers to understand and participate in the revision process.     

Predictors of punding in Parkinson's disease: results from a questionnaire survey.

Dopamine replacement therapy (DRT) for Parkinson's disease (PD) has recently been linked to the development of a number of nonmotor behavioral control problems. Punding, one of these nonmotor problems, is a term used to describe complex, purposeless stereotyped behaviors such as the repetitive handling or sorting of objects. A self-report questionnaire was adapted to assess punding in the context of dysfunctional hobby-related activities. We report the results of a survey of PD outpatients from a PD research clinic (n = 141) and non-PD controls (n = 103); conducted to identify clinical and psychological factors predictive of punding behaviors. The PD group reported hobbies and activities, which scored significantly higher on the Punding Scale than controls. Higher impulsivity, poorer disease-related quality of life, younger age of disease onset, and concomitant daily medication dosage from dopamine receptor agonists were independently predictive of higher Punding Scale scores in the PD group. These findings are similar to those seen in dopamine dysregulation syndrome, and provide further evidence for the role of impulsivity and age at disease onset in DRT-related nonmotor behavioral problems in PD.     

Phase-sensitive cardiac tagging--REALTAG.

Fully inverting spins, instead of merely saturating them, provides superior contrast for tagging procedures. The resulting improvement in tag contrast-to-noise ratio (CNR) yields higher-precision tag detection. Also, thinner slices and hence reduced tag separations can be employed, providing displacement and strain measurements with better spatial resolution. Alternatively, the improved tag contrast can be used to obtain cine images covering a greater portion of the cardiac cycle. The use of standard magnitude reconstruction for images of these inversion tags causes rectification of the negative-valued signals from the tags, confounding the image interpretation. Therefore, a phase-sensitive reconstruction scheme of the inverted tags must be employed. Here we demonstrate the implementation of inverted tags with phase-sensitive reconstruction in a ramped-flip-angle, steady-state free precession (SSFP) sequence.