Quorum Sensing Behavior in the Model Unicellular Eukaryote Chlamydomonas reinhardtii.

Microbial communities display behavioral changes in response to variable environmental conditions. In some bacteria, motility increases as a function of cell density, allowing for population dispersal before the onset of nutrient scarcity. Utilizing automated particle tracking, we now report on a population-dependent increase in the swimming speeds of the photosynthetic unicellular eukaryotes Chlamydomonas reinhardtii and C. moewussi. Our findings confirm that this acceleration in swimming speed arises as a function of culture density, rather than with age and/or nutrient availability. Furthermore, this phenomenon depends on the synthesis and detection of a low-molecular-weight compound which can be transferred between cultures and stimulates comparable effects across both species, supporting the existence of a conserved phenomenon, not unlike bacterial quorum sensing, among members of this genus. The potential expansion of density-dependent phenomena to a new group of unicellular eukaryotes provides important insight into how microbial populations evolve and regulate "social" behaviors.

Label Design Affects Medication Safety in an Operating Room Crisis: A Controlled Simulation Study.

OBJECTIVE: Several factors contribute to medication errors in clinical practice settings, including the design of medication labels. The objective of this study was to quantify the impact of label design on medication safety in a realistic, high-stress clinical situation. METHODS: Ninety-six anesthesia trainee participants were randomly assigned to either the redesigned or the current label condition. Participants were blinded to the study's focus on medication label design and their assigned label condition. Each participant was the sole anesthesia provider in a simulated operating room scenario involving an unexpected vascular injury. The surgeon asked the participant to administer hetastarch to the simulated patient because of hemodynamic instability. The fluid drawer of the anesthesia cart contained three 500-ml intravenous bags of hetastarch and one 500-ml intravenous bag of lidocaine. We hypothesized that redesigned labels would help participants correctly select hetastarch from the cart. If the participants incorrectly selected lidocaine from the cart, we hypothesized that the redesigned labels would help participants detect the lidocaine before administration. RESULTS: The percentage of participants who correctly selected hetastarch from the cart was significantly higher for the redesigned labels than the current labels (63% versus 40%; odds ratio, 2.61 [95% confidence interval, 1.1-6.1]; P = 0.03). Of the participants who incorrectly selected lidocaine from the cart, the percentage who detected the lidocaine before administration did not differ by label condition. CONCLUSIONS: The redesigned labels helped participants correctly select hetastarch from the cart, thus preventing some potentially catastrophic medication errors from reaching the simulated patient.

Effect of a simulation educational intervention on knowledge, attitude, and patient transfer skills: from the simulation laboratory to the clinical setting.

INTRODUCTION: Musculoskeletal injury in the workplace is the primary work-related factor in loss of nursing personnel from the workforce. Moving or transferring patients is the dominant contributing event. A simulation educational approach has not been closely studied in this area but may have advantages over traditional approaches. Specific aims were to (1) evaluate the effect of a simulation intervention on success of patient transfers in a clinical setting and (2) measure change in participants' knowledge and attitude as a result of the intervention. METHODS: A prospective, observational, longitudinal design was used. Baseline patient transfer observations were conducted on control and intervention units. An optimum task set was developed using hierarchical task analysis methods. Subjects (N = 71) completed pre- and postintervention knowledge and attitude assessments. The intervention consisted of simulated patient transfers using a mannequin, education, and training, followed by repeated simulated transfers using a mannequin with debriefing. Observations of patient transfers in patient care areas were repeated at 4 and 12 weeks. RESULTS: Patient transfer success improved from 66% at baseline to 88% at the 4-week measurement point (t = 7.447, P ≤ 0.0004). At 12 weeks, transfer success had decreased to 71%, with addition of new employees between weeks 4 and 12 confounding the 12-week measurement. Knowledge improved from a baseline of 65% to 95% postsimulation intervention (z = -6.634, P ≤ 0.0004). Attitude change was also evaluated with significance seen with 12 of 15 items (P ≤ 0.05). CONCLUSIONS: A simulation intervention was successful in significantly improving knowledge and changing subject perceptions with regard to this task. Skills acquired through simulation successfully transferred to the clinical setting. Improvement in success for patient moves not trained in the simulation laboratory suggests that acquired skills were generalizable and supports application to different settings.

High-frequency jet ventilation: utility in posterior left atrial catheter ablation.

BACKGROUND: Percutaneous catheter ablation in the posterior left atrium (LA) is a technically demanding procedure that in our experience is best accomplished using general anesthesia, including endotracheal intubation and mechanical ventilation. However, using conventional intermittent positive-pressure ventilation (IPPV) technique, we were dissatisfied with motion of the posterior LA. This occurred during changes in lung volume, which destabilized ablation electrode-endocardial contact. We hypothesized that use of high-frequency jet ventilation (HFJV), a low-volume, fast-rate technique, would reduce posterior LA motion and thus facilitate the ablation procedure. OBJECTIVES: The purpose of this study was to demonstrate that, relative to IPPV, HFJV reduces posterior LA motion and facilitates catheter ablation in this region. METHODS: Patients who underwent posterior LA ablation using HFJV (n = 36) were retrospectively compared with those in whom IPPV (n = 36) was used. Indices examined included number of radiofrequency energy applications, electrode temperature, and procedure time. A prospective direct comparison of the impact of HFJV and IPPV on LA volume and mechanical function was performed in an additional 10 patients. RESULTS: Fewer ablation lesions were required in the HFJV group because of fewer incidences of ablation electrode dislodgment, resulting in significantly decreased procedure time. Although there was no significant difference in maximal electrode temperature achieved during radiofrequency application, temperature variation was diminished in the HFJV group. Direct comparison demonstrated that HFJV produced less variation in LA volume, pressure, pulmonary vein blood flow velocity, and posterior LA position than IPPV. CONCLUSION: Relative to IPPV, HFJV yields a more stable posterior LA environment, thus facilitating catheter ablation. Use of HFJV may be applicable to other interventional cardiovascular procedures.

Quality of life in spinal cord injured individuals and their caregivers during the initial 6 months following rehabilitation.

Addressing quality of life (QOL) issues in the spinal cord injured (SCI) population is imperative as the majority survive their initial injury and longevity now approaches that of the general population. The purpose of this mixed method, descriptive, longitudinal feasibility study was to describe and compare QOL in 10 adult SCI individuals and their family caregivers (FCs) during the initial 6 months following rehabilitation. Instruments used were the SF-36 and two horizontal visual analog scales, one for pain and one for QOL. Participants completed the instruments and a face-to-face in-depth interview at 1-, 3-, and 6-months following inpatient rehabilitation. SCI individuals reported low physical function, role physical (RP), and role emotional (RE) scores on the SF-36, while reporting high general health (GH), mental health and social functioning on the SF-36. FCs reported lower RP, GH and vitality scores, while reporting higher physical functioning and RE scores. On the visual analog scales, persons with SCI reported lower QOL while FCs reported more pain at 3 and 6 months. This study suggests that more work is needed to identify interventions which could enhance QOL during the transition from rehabilitation to home for SCI individuals and their FCs.