Rhizo-lysimetry: facilities for the simultaneous study of root behaviour and resource use by agricultural crop and pasture systems.

BACKGROUND: Rhizo-lysimeters offer unique advantages for the study of plants and their interactions with soils. In this paper, an existing facility at Charles Sturt University in Wagga Wagga Australia is described in detail and its potential to conduct both ecophysiological and ecohydrological research in the study of root interactions of agricultural crops and pastures is quantitatively assessed. This is of significance to future crop research efforts in southern Australia, in light of recent significant long-term drought events, as well as potential impacts of climate change as predicted for the region. The rhizo-lysimeter root research facility has recently been expanded to accommodate larger research projects over multiple years and cropping rotations. RESULTS: Lucerne, a widely-grown perennial pasture in southern Australia, developed an expansive root system to a depth of 0.9 m over a twelve month period. Its deeper roots particularly at 2.05 m continued to expand for the duration of the experiment. In succeeding experiments, canola, a commonly grown annual crop, developed a more extensive (approximately 300%) root system than wheat, but exhibited a slower rate of root elongation at rates of 7.47 x 10-3 m day-1 for canola and 1.04 x10-2 m day-1 for wheat. A time domain reflectometry (TDR) network was designed to accurately assess changes in soil water content, and could assess water content change to within 5% of the amount of water applied. CONCLUSIONS: The rhizo-lysimetry system provided robust estimates of root growth and soil water change under conditions representative of a field setting. This is currently one of a very limited number of global research facilities able to perform experimentation under field conditions and is the largest root research experimental laboratory in the southern hemisphere.

Small-dose dexamethasone improves quality of recovery scores after elective cardiac surgery: a randomized, double-blind, placebo-controlled study.

OBJECTIVES: The use of steroid therapy in cardiac surgical patients remains controversial. The aim of this clinical investigation was to determine the effect of small-dose dexamethasone therapy on patient-perceived quality of recovery (QoR) scores in elective cardiac surgical patients. In addition, the authors assessed the impact of dexamethasone on the incidence of common adverse events after cardiopulmonary bypass (CPB). DESIGN: A prospective, randomized study. SETTING: University hospitals. PARTICIPANTS: One hundred seventeen patients undergoing cardiac surgery with CPB and anticipated early tracheal extubation. INTERVENTIONS: Subjects were randomized to receive either dexamethasone (dexamethasone group, 8 mg at the induction of anesthesia and at the initiation of CPB) or placebo (control group, saline). MEASUREMENTS AND MAIN RESULTS: The QoR was assessed using the QoR-40 scoring system preoperatively and on postoperative days (PODs) 1 and 2. Secondary outcome measures assessed in the postoperative period included nausea, vomiting, fatigue, febrile responses, shivering, pulmonary gas exchange, and analgesic requirements. Global QoR-40 scores (median [range]) were higher in the dexamethasone group compared with the control group on POD 1 (167 [133-192] v 157 [108-195]; p < 0.0001) and POD 2 (173 [140-196] v 166 [122-196]; p = 0.001). In the dexamethasone group, improved QoR was observed in the QoR-40 dimensions of emotional state (p = 0.002), physical comfort (p = 0.0001-0.006), and pain (p < 0.0001). The incidences or severity of postoperative fatigue (p < 0.0001), febrile responses (p < 0.0001), and shivering (p = 0.001) were reduced in the dexamethasone group. CONCLUSIONS: Patient-perceived postoperative QoR in cardiac surgical patients is enhanced significantly by small-dose dexamethasone treatment.

Progress toward improving the quality of cardiac arrest medical team responses at an academic teaching hospital.

BACKGROUND: Internal medicine (IM) residents who undergo simulation-based advanced cardiac life support (ACLS) training are significantly more likely to manage actual events according to American Heart Association (AHA) standards than nontrained residents. How long ACLS skills are retained is unknown. METHODS: We conducted a retrospective case-control study of ACLS responses from January to June 2008 and reviewed medical records to assess adherence to AHA standards. Cases and controls are team responses to ACLS events divided into those directed by postgraduate year 2 (PGY-2) IM resident leaders versus those managed by PGY-3 IM resident leaders. Residents in 2008 completed an educational program featuring deliberate practice in ACLS using a human patient simulator during their second year. Medical records of ACLS events were reviewed to assess adherence to AHA guidelines. We evaluated the effects of simulation training on quality of ACLS care during the 2008 period and in comparison with historical 2004 data. RESULTS: In 2008, 1 year after simulation training, PGY-3 residents showed the same adherence to AHA standards (88% [SD, 17%]) as that of PGY-2 residents who were newly simulator trained (86% [SD, 18%]) (P  =  .77). Previously, in 2004, PGY-2 simulator-trained residents showed significantly higher adherence to AHA standards (68% [SD, 20%]) than nonsimulator-trained PGY-3 residents (44% [SD, 20%]) (P < .001). All resident groups in 2008 outperformed their 2004 peers. CONCLUSIONS: Improved quality of ACLS care was maintained by 2008 PGY-3 simulator-trained residents 1 year after training, likely due to skill retention rather than increased clinical experience, as a prior cohort of PGY-3 residents did not perform as well as PGY-2 residents in actual ACLS care. Our results confirm prior work regarding the impact of simulation-based education to improve the quality of actual patient care.

A longitudinal study of internal medicine residents' retention of advanced cardiac life support skills.

BACKGROUND: Internal medicine residents must be competent in Advanced Cardiac Life Support (ACLS) for board certification. Traditional ACLS courses have limited ability to enable residents to achieve and maintain skills. Educational programs featuring reliable measurements and improved retention of skills would be useful for residency education. METHOD: We developed a training program using a medical simulator, small-group teaching and deliberate practice. Residents received traditional ACLS education and subsequently participated in four two-hour educational sessions using the simulator. Resident performance in six simulated ACLS scenarios was assessed using a standardized checklist. RESULTS: After the program, resident ACLS skill improved significantly. The cohort was followed prospectively for 14 months and the skills did not decay. CONCLUSIONS: Use of a simulation-based educational program enabled us to achieve and maintain high levels of resident performance in simulated ACLS events. Given the limitations of traditional methods to train, assess and maintain competence, simulation technology can be a useful adjunct in high-quality ACLS education.

Development of an objective scoring system for measurement of resident performance on the human patient simulator.

BACKGROUND: The decrease in the percentage of patients having cesarean delivery during general anesthesia has led some educators to advocate the increased use of simulation-based training for this anesthetic. The authors developed a scoring system to measure resident performance of this anesthetic on the human patient simulator and subjected the system to tests of validity and reliability. METHODS: A modified Delphi technique was used to achieve a consensus among several experts regarding a standardized scoring system for evaluating resident performance of general anesthesia for emergency cesarean delivery on the human patient simulator. Eight third-year and eight first-year anesthesiology residents performed the scenario and were videotaped and scored by four attending obstetric anesthesiologists. RESULTS: Third-year residents scored an average of 150.5 points, whereas first-year residents scored an average of 128 points (P = 0.004). The scoring instrument demonstrated high interrater reliability with an intraclass correlation coefficient of 0.97 (95% confidence interval, 0.94-0.99) compared with the average score. CONCLUSIONS: The developed scoring tool to measure resident performance of general anesthesia for emergency cesarean delivery on the patient simulator seems both valid and reliable in the context in which it was tested. This scoring system may prove useful for future studies such as those investigating the effect of simulator training on objective assessment of resident performance.

Graduating internal medicine residents' self-assessment and performance of advanced cardiac life support skills.

Internal medicine residents in the US must be competent to perform procedures including Advanced Cardiac Life Support (ACLS) to become board-eligible. Our aim was to determine if residents near graduation could assess their skills in ACLS procedures accurately. Participants were 40 residents in a university-based training program. Self-assessments of confidence in managing six ACLS scenarios were measured on a 0 (very low) to 100 (very high) scale. These were compared to reliable observational ratings of residents' performance on a high-fidelity simulator using published treatment protocols. Residents expressed strong self-confidence about managing the scenarios. Residents' simulator performance varied widely (range from 45% to 94%). Self-confidence assessments correlated poorly with performance (median r = 0.075). Self-assessment of performance by graduating internal medicine residents was not accurate in this study. The use of self-assessment to document resident competence in procedures such as ACLS is not a proxy for objective evaluation.

Mastery learning of advanced cardiac life support skills by internal medicine residents using simulation technology and deliberate practice.

BACKGROUND: Internal medicine residents must be competent in advanced cardiac life support (ACLS) for board certification. OBJECTIVE: To use a medical simulator to assess postgraduate year 2 (PGY-2) residents' baseline proficiency in ACLS scenarios and evaluate the impact of an educational intervention grounded in deliberate practice on skill development to mastery standards. DESIGN: Pretest-posttest design without control group. After baseline evaluation, residents received 4, 2-hour ACLS education sessions using a medical simulator. Residents were then retested. Residents who did not achieve a research-derived minimum passing score (MPS) on each ACLS problem had more deliberate practice and were retested until the MPS was reached. PARTICIPANTS: Forty-one PGY-2 internal medicine residents in a university-affiliated program. MEASUREMENTS: Observational checklists based on American Heart Association (AHA) guidelines with interrater and internal consistency reliability estimates; deliberate practice time needed for residents to achieve minimum competency standards; demographics; United States Medical Licensing Examination Step 1 and Step 2 scores; and resident ratings of program quality and utility. RESULTS: Performance improved significantly after simulator training. All residents met or exceeded the mastery competency standard. The amount of practice time needed to reach the MPS was a powerful (negative) predictor of posttest performance. The education program was rated highly. CONCLUSIONS: A curriculum featuring deliberate practice dramatically increased the skills of residents in ACLS scenarios. Residents needed different amounts of training time to achieve minimum competency standards. Residents enjoy training, evaluation, and feedback in a simulated clinical environment. This mastery learning program and other competency-based efforts illustrate outcome-based medical education that is now prominent in accreditation reform of residency education.

Comparison of two standard-setting methods for advanced cardiac life support training.

BACKGROUND: This study used the Angoff and Hofstee standard-setting methods to derive minimum passing scores for six advanced cardiac life support (ACLS) procedures. METHOD: An expert panel provided item-based (Angoff) and group-based (Hofstee) judgments about six ACLS performance checklists on two occasions separated by ten weeks. Interrater reliabilities and test-retest reliability (stability) of the judgments were calculated. Derived ACLS passing standards are compared to historical ACLS performance data from two groups of ACLS-trained internal medicine residents. RESULTS: Both the Angoff and Hofstee standard-setting methods produced reliable and stable data. Hofstee minimum passing scores (MPSs) were uniformly more stringent than Angoff MPSs. Interpretation of historical ACLS performance data from medical residents shows the MPSs derived in this study would yield higher-than-expected failure rates. CONCLUSION: Systematic standard setting for ACLS procedures is a necessary step toward the creation of mastery learning educational programs.

Simulation-based training of internal medicine residents in advanced cardiac life support protocols: a randomized trial.

BACKGROUND: Internal medicine residents must be competent in Advanced Cardiac Life Support (ACLS) for board certification. PURPOSE: The purpose was to use a medical simulator to assess baseline proficiency in ACLS and determine the impact of an intervention on skill development. METHOD: This was a randomized trial with wait-list controls. After baseline evaluation in all residents, the intervention group received 4 education sessions using a medical simulator. All residents were then retested. After crossover, the wait-list group received the intervention, and residents were tested again. Performance was assessed by comparison to American Heart Association guidelines for treatment of ACLS conditions with interrater and internal consistency reliability estimates. RESULTS: Performance improved significantly after simulator training. No improvement was detected as a function of clinical experience alone. The educational program was rated highly.

Proteomic analysis of rice leaves during drought stress and recovery.

Three-week old plants of rice (Oryza sativa L. cv CT9993 and cv IR62266) developed gradual water stress over 23 days of transpiration without watering, during which period the mid-day leaf water potential declined to approximately -2.4 MPa, compared with approximately -1.0 MPa in well-watered controls. More than 1000 protein spots that were detected in leaf extracts by proteomic analysis showed reproducible abundance within replications. Of these proteins, 42 spots showed a significant change in abundance under stress, with 27 of them exhibiting a different response pattern in the two cultivars. However, only one protein (chloroplast Cu-Zn superoxide dismutase) changed significantly in opposite directions in the two cultivars in response to drought. The most common difference was for proteins to be up-regulated by drought in CT9993 and unaffected in IR62266; or down-regulated by drought in IR62266 and unaffected in CT9993. By 10 days after rewatering, all proteins had returned completely or largely to the abundance of the well-watered control. Mass spectrometry helped to identify 16 of the drought-responsive proteins, including an actin depolymerizing factor, which was one of three proteins detectable under stress in both cultivars but undetectable in well-watered plants or in plants 10 days after rewatering. The most abundant protein up-regulated by drought in CT9993 and IR62266 was identified only after cloning of the corresponding cDNA. It was found to be an S-like RNase homologue but it lacked the two active site histidines required for RNase activity. Four novel drought-responsive mechanisms were revealed by this work: up-regulation of S-like RNase homologue, actin depolymerizing factor and rubisco activase, and down-regulation of isoflavone reductase-like protein.