Right ventricular and pulmonary artery pulse pressure variation and systolic pressure variation for the prediction of fluid responsiveness: an interventional study in coronary artery bypass surgery patients.

PURPOSE: Predicting fluid responsiveness is essential when treating surgical or critically ill patients. When using a pulmonary artery catheter, pulse pressure variation and systolic pressure variation can be calculated from right ventricular and pulmonary artery pressure waveforms. METHODS: We conducted a prospective interventional study investigating the ability of right ventricular pulse pressure variation (PPVRV) and systolic pressure variation (SPVRV) as well as pulmonary artery pulse pressure variation (PPVPA) and systolic pressure variation (SPVPA) to predict fluid responsiveness in coronary artery bypass (CABG) surgery patients. Additionally, radial artery pulse pressure variation (PPVART) and systolic pressure variation (SPVART) were calculated. The area under the receiver operating characteristics (AUROC) curve with 95%-confidence interval (95%-CI) was used to assess the capability to predict fluid responsiveness (defined as an increase in cardiac index of > 15%) after a 500 mL crystalloid fluid challenge. RESULTS: Thirty-three patients were included in the final analysis. Thirteen patients (39%) were fluid-responders with a mean increase in cardiac index of 25.3%. The AUROC was 0.60 (95%-CI 0.38 to 0.81) for PPVRV, 0.63 (95%-CI 0.43 to 0.83) for SPVRV, 0.58 (95%-CI 0.38 to 0.78) for PPVPA, and 0.71 (95%-CI 0.52 to 0.89) for SPVPA. The AUROC for PPVART was 0.71 (95%-CI 0.53 to 0.89) and for SPVART 0.78 (95%-CI 0.62 to 0.94). The correlation between pulse pressure variation and systolic pressure variation measurements derived from the different waveforms was weak. CONCLUSIONS: Right ventricular and pulmonary artery pulse pressure variation and systolic pressure variation seem to be weak predictors of fluid responsiveness in CABG surgery patients.

Factors which influence the complications of external ventricular cerebrospinal fluid drainage.

BACKGROUND: External ventricular drainage (EVD) is one of the most common neurosurgical procedures in emergencies. This study aims to find out which factors influence the occurrence of EVD-related complications in a comparative investigation of metal needles and polyurethane catheters. This is the first clinical study comparing these two systems. METHODS: Adult patients undergoing pre-coronal EVD placement via freehand burr hole trepanation were included in this prospective study. The exclusion criteria were the open EVD insertion and/or a pre-existing infectious disease of the central nervous system. RESULTS: Two hundred consecutive patients were enrolled. Of these, 100 patients were treated by using metal EVD (group 1) and 100 patients with polyurethane catheters (group 2). The overall complication rate was 26% (misplacement 13.5%, hemorrhage 12.5%, infection 2.5%, and dislocation 1%) without statistically significant differences between both groups. Generalized brain edema and midline shift had a significant influence on misplacements (generalized brain edema: p = 0.0002, Cramer-V: 0.307, OR = 7.364, 95% CI: 2.691-20.148; all patients: p = 0.001, Cramer-V: 0.48, OR = 43.5, 95% CI: 4.327-437.295; group 1: p = 0.047, Cramer-V: 0.216, OR = 3.75, 95% CI: 1.064-13.221; group 2: midline shift: p = 0.038, Cramer-V: 0.195, OR = 3.626, 95% CI: 1.389-9.464) all patients: p = 0.053, Cramer-V: 0.231, OR = 5.533, 95% CI 1.131-27.081; group 1: p = 0.138, Cramer-V: 0.168, OR = 2.769, 95% CI: 0.813-9.429 group 2. Hemorrhages were associated with the use of oral anticoagulants or antiplatelet therapy (p = 0.002; Cramer-V: 0.220, OR = 3.798, 95% CI: 1.572-9.175) with a statistically similar influence in both groups. CONCLUSION: Generalized brain edema has a significant influence on misplacements in both groups. Midline shift lost its significance when considering only the patients in group 2. Patients under oral anticoagulation and antiplatelet therapy have increased odds of EVD-associated hemorrhage. Metal needles and polyurethane catheters are equivalent in terms of patient safety when there are no midline shift and generalized brain edema.

Understanding how the motivational dimension of learning is influenced by clinical teaching in medical education: A prospective cohort study.

INTRODUCTION: Many changes of medical curricula have been conducted in the past years. Based on learning psychology, three dimensions of learning have to be covered, in order to create the best possible curricula: Cognitive, metacognitive and motivational. The metacognitive and cognitive dimension (what/how to teach) have always been considered and the motivational dimension has been neglected, although the importance and benefits of motivation in learning have been emphasized repeatedly. One way to influence motivation in medical curricula are the teaching formats, as it has been shown that the construction of a curriculum can influence students' motivation. So far, evidence about the motivational effects of teaching formats are scarce. METHODS: In a prospective interventional cohort study, 145 3rd year medical students were sampled. The effects of a 3-day bedside teaching in the operating theatre and two simulation-based trainings on students' motivation (outcome measure) were analysed. It was hypothesized, that the simulation training and the bedside teaching enhance autonomous motivation and decrease controlled motivation. RESULTS: The bedside-teaching decreased external (controlled) motivation (-0.14, p = .013, 95% CI [-0.24, -0.03]), alongside with identified (autonomous) motivation (-0.22, p < .001, 95% CI [-0.34, -0.10]). The simulation-based trainings did not change students' motivation. CONCLUSION: To prevent the unintended decrease of identified (autonomous) motivation, undergraduates should be supervised and introduced carefully, when attending bedside teaching in unknown medical fields. Simulation-based medical education certainly has plenty of benefits in medical education but its effects on the motivational dimension of learning needs further investigations.

Implementation of Basic Life Support training in schools: a randomised controlled trial evaluating self-regulated learning as alternative training concept.

BACKGROUND: The Kids save lives statement recommends annual Basic Life Support (BLS) training for school children but the implementation is challenging. Trainings should be easy to realise and every BLS training should be as effective as possible to prepare learners for lifesaving actions. Preparedness implies skills and positive beliefs in the own capability (high self-efficacy). METHODS: This randomized controlled cluster study investigates, if self-regulated learning promotes self-efficacy and long-term retention of practical BLS skills. Students in the age of 12 years participated in a practical training in BLS and a scenario testing of skills. In the control group the practical training was instructor-led. In the intervention group the students self-regulated their learning processes and feedback was provided by the peer-group. The primary outcome self-efficacy for helping in cardiac arrest after the training and 9 months later was analysed using a multilevel mixed model. Means and pass-rates for BLS skills were secondary outcomes. RESULTS: Contrary to the assumptions, this study could not measure a higher self-efficacy for helping in cardiac arrest of the students participating in the intervention (n = 307 students) compared to the control group (n = 293 students) after training and at the follow-up (mean difference: 0.11 points, 95% CI: - 0.26 to 0.04, P = 0.135). The odds to pass all items of the BLS exam was not significantly different between the groups (OR 1.11, 95% CI: 0.81 to 1.52, p = 0.533). Self-regulated learning was associated with a higher performance of male students in the BLS exam (mean score: 7.35) compared to females of the intervention (female: 7.05) and compared to males of the control (7.06). CONCLUSION: This study could not resolve the question, if self-regulated learning in peer-groups improves self-efficacy for helping in cardiac arrest. Self-regulated learning is an effective alternative to instructor-led training in BLS skills training and may be feasible to realise for lay-persons. For male students self-regulated learning seems to be beneficial to support long-term retention of skills. TRIAL REGISTRATION: ISRCTN17334920, retrospectively registered 07.03.2019.

Basic life support training using shared mental models improves team performance of first responders on normal wards: A randomised controlled simulation trial.

INTRODUCTION: Survival of in-hospital cardiac arrest (IHCA) depends on fast and effective action of the first responding team. Not only technical skills, but professional teamwork is required. Observational studies and theoretical models suggest that shared mental models of members improve teamwork. This study investigated if a training on shared mental models, improves team performance in simulated in-hospital cardiac arrest. METHODS: On the background of an introduction of mandatory Basic Life Support (BLS) training for clinical staff a randomized controlled trial was performed to compare two training methods. Staff from clinical departments was randomised to receive either a conventional instructor led training (control group) or an interventional training (intervention group). The interventional training was based on self-directed learning of the group in order to develop shared mental models. Primary outcome were mean scores of the team assessment scale (TAS) and the hands-off time. Secondary outcome were mean scores for quality of BLS. RESULTS: Performance of 75 teams of the interventional and 66 of the control group was analysed. The hands-off time was significantly lower in the interventional group (5.42% vs. 8.85%, p = 0.029). Scores of the TAS and the overall BLS score were high and not significantly different between the groups. Hands-off time correlated significantly negative with all TAS items. CONCLUSION: BLS training for clinical staff which creates shared mental models reduces hands-off time in a simulated cardiac arrest scenario. Training methods establishing shared mental models of team members can be considered for effective team trainings without adding additional training time.

Anaesthesiology students' Non-Technical skills: development and evaluation of a behavioural marker system for students (AS-NTS).

BACKGROUND: Non-Technical Skills (NTS) are becoming more important in medical education. A lack of NTS was identified as a major reason for unsafe patient care, favouring adverse events and team breakdown. Therefore, the training of NTS should already be implemented in undergraduate teaching. The goal of our study was to develop and validate the Anaesthesiology Students' Non-Technical Skills (AS-NTS) as a feasible rating tool to assess students' NTS in emergency and anaesthesiology education. METHODS: The development of AS-NTS was empirically grounded in expert- and focus groups, field observations and data from NTS in medical fields. Validation, reliability and usability testing was conducted in 98 simulation scenarios, during emergency and anaesthesiology training sessions. RESULTS: AS-NTS showed an excellent interrater reliability (mean 0.89), achieved excellent content validity indexes (at least 0.8) and was rated as feasible and applicable by educators. Additionally, we could rule out the influence of the raters' anaesthesiology and emergency training and experience in education on the application of the rating tool. CONCLUSIONS: AS-NTS provides a structured approach to the assessment of NTS in undergraduates, providing accurate feedback. The findings of usability, validity and reliability indicate that AS-NTS can be used by anaesthesiologists in different year of postgraduate training, even with little experience in medical education.

Inhalative and intravenous stimulation of soluble guanylate cyclase reduces pulmonary vascular resistance and increases cardiac output in experimental septic shock.

The effects of inhaled and intravenous application of a guanylate cyclase stimulator (BAY 41-8543) on pulmonary vascular resistance (PVR) and cardiac output (CO) were investigated in an experimental model of septic shock. Following induction of septic shock, anaesthetized pigs (n=31) were randomly place into two groups receiving different interventions. Animals in the first group received intravenous BAY 41-8543 (0.6 mg), inhalative BAY 41-8543 (6 mg) or a placebo. In the second group, the dosage of BAY 41-8543 was increased two-fold or combined with inhalation of nitric oxide (iNO). Intravenous and inhaled administration of BAY 41-8543 resulted in a significantly (P<0.05) reduced PVR and increased CO compared with the placebo. Increasing the dosage of BAY 41-8543 or combining it with iNO did not further decrease PVR. The results of the present study indicate that BAY 41-8543 effectively reduces PVR and increases CO in septic shock, through inhaled or intravenous routes of administration.

Teaching school children basic life support improves teaching and basic life support skills of medical students: A randomised, controlled trial.

BACKGROUND: The "kids save lives" joint-statement highlights the effectiveness of training all school children worldwide in cardiopulmonary resuscitation (CPR) to improve survival after cardiac arrest. The personnel requirement to implement this statement is high. Until now, no randomised controlled trial investigated if medical students benefit from their engagement in the BLS-education of school children regarding their later roles as physicians. The objective of the present study is to evaluate if medical students improve their teaching behaviour and CPR-skills by teaching school children in basic life support. METHODS: The study is a randomised, single blind, controlled trial carried out with medical students during their final year. In total, 80 participants were allocated alternately to either the intervention or the control group. The intervention group participated in a CPR-instructor-course consisting of a 4h-preparatory seminar and a teaching-session in BLS for school children. The primary endpoints were effectiveness of teaching in an objective teaching examination and pass-rates in a simulated BLS-scenario. RESULTS: The 28 students who completed the CPR-instructor-course had significantly higher scores for effective teaching in five of eight dimensions and passed the BLS-assessment significantly more often than the 25 students of the control group (Odds Ratio (OR): 10.0; 95%-CI: 1.9-54.0; p=0.007). CONCLUSIONS: Active teaching of BLS improves teaching behaviour and resuscitation skills of students. Teaching school children in BLS may prepare medical students for their future role as a clinical teacher and support the implementation of the "kids save lives" statement on training all school children worldwide in BLS at the same time.

Positive end-expiratory pressure does not compromise myocardial contractility in myocardial ischemia/reperfusion.

Therapy for severe myocardial ischemia/reperfusion sometimes necessitates intermittent positive pressure ventilation, which may impair left ventricular function by reduction of ventricular loading. It is unknown today whether positive airway pressure also affects contractile force after myocardial ischemia/reperfusion. The authors tested whether positive end-expiratory pressure (PEEP) impairs myocardial contractility in acute ischemic heart failure. In 11 anesthetized mechanically ventilated pigs (28 +/- 3 kg), cardiac output (CO, aortic flow probe), load-independent parameters of left ventricular contractility (conductance method: preload recruitable stroke work [PRSW] and end-systolic elastance [E(es)]) and preload (end-diastolic volume [EDV] conductance) were assessed before and after myocardial ischemia and reperfusion (left anterior descending artery occlusion, 60 min). Data were taken during PEEP 0, 5, and 10 cm H2O. Before myocardial ischemia, both PEEP 5 and 10 cm H2O reduced CO (P < 0.05) because of a reduction of EDV (P < 0.05, PEEP 10 cm H2O). The PRSW remained unchanged (not significant [NS]) and E(es) increased (P < 0.05, PEEP 10 cm H2O). After myocardial ischemia/reperfusion, CO and PRSW, but not E(es) (NS), deteriorated markedly. At the same time, PEEP 10 cm H2O reduced CO (P < 0.05) and, slightly, EDV (NS). Now, both PRSW (P < 0.05, PEEP 5 cm H2O) and E(es) (P < 0.05, PEEP 10 cm H2O) improved upon ventilation with PEEP. In our model, the administration of PEEP impaired global left ventricular function before and after myocardial ischemia/reperfusion. The observed impairment is not attributable to compromised contractility.