Accuracy of cumulative volumes of fluid challenge to assess fluid responsiveness in critically ill patients with acute circulatory failure: a pharmacodynamic approach.

BACKGROUND: The relationship between the dose (volume of fluid) and the effect (increase of stroke volume [SV]) has been poorly described. We hypothesised that the analysis of the dynamic response of SV during fluid challenge (FC) helps to determine the optimal volume of FC, along with its diagnostic accuracy parameters for fluid responsiveness. METHODS: A prospective observational study was conducted in critically ill patients with circulatory failure. Patients monitored with oesophageal Doppler and assigned to an FC of 500 ml of crystalloid were included. The areas under the curve (AUC) and 95% confidence intervals (CI95) of the receiver operating characteristic curves for cumulative volumes from 50 to 450 ml were determined for fluid responsiveness (SV increase ≥15% from baseline) along with other parameters of diagnostic accuracy. In the pharmacodynamic analysis, dose-effect and dose-response models were constructed, with determination of median and 90% effective dose (ED50 and ED90). RESULTS: Forty-five patients were included. The AUC increased with cumulative volumes of FC up to 250 ml (AUC250 0.93 [CI95: 0.85-1.00]), followed by a plateau above 0.95 of AUC. The optimal volume was 250 ml, associated with a specificity of 0.89 [CI95: 0.78-1.00], a sensitivity of 0.92 [CI95: 0.69-1.00], and a threshold of 9.6% increase in SV. The ED50 was 156 [CI95: 136-177] ml and the ED90 was 312 [CI95: 269-352] ml. CONCLUSIONS: A volume of FC of 250 ml with a threshold of 9.6% increase in SV showed the highest accuracy in detecting fluid responsiveness in critically ill patients with shock. CLINICAL TRIAL REGISTRATION: .

Serious game versus online course for pretraining medical students before a simulation-based mastery learning course on cardiopulmonary resuscitation: A randomised controlled study.

BACKGROUND: Although both recorded lectures and serious games have been used to pretrain health professionals before simulation training on cardiopulmonary resuscitation, they have never been compared. OBJECTIVE: The aim of this study was to compare an online course and a serious game for pretraining medical students before simulation-based mastery learning on the management of sudden cardiac arrest. DESIGN: A randomised controlled trial. Participants were pretrained using the online course or the serious game on day 1 and day 7. On day 8, each participant was evaluated repeatedly on a scenario of cardiac arrest until reaching a minimum passing score. SETTING: Department of Simulation in Healthcare in a French medical faculty. PARTICIPANTS: Eighty-two volunteer second-year medical students participated between June and October 2016 and 79 were assessed for primary outcome. INTERVENTIONS: The serious game used was Staying Alive, which involved a 3D realistic environment, and the online course involved a PowerPoint lecture. MAIN OUTCOME MEASURES: The median total training time needed for students to reach the minimum passing score on day 8. This same outcome was also assessed 4 months later. RESULTS: The median training time (interquartile range) necessary for students to reach the minimum passing score was similar between the two groups: 20.5 (15.8 to 30.3) minutes in the serious game group versus 23 (15 to 32) minutes in the online course group, P = 0.51. Achieving an appropriate degree of chest compression was the most difficult requirement to fulfil for students in both groups. Four months later, the median training time decreased significantly in both groups, but no correlation was found at an individual level with the training times observed on day 8. CONCLUSION: The serious game used in this study was not superior to an online course to pretrain medical students in the management of a cardiac arrest. The absence of any correlation between the performances of students evaluated during two training sessions separated by 4 months suggests that some elements in the management of cardiac arrest such as compression depth can only be partially learned and retained after a simulation-based training. TRIAL REGISTRATION: ClinicalTrials.gov-NCT02758119.

Prevalence and time-course of diaphragmatic dysfunction following lung resection: A repeated ultrasonic assessment.

PURPOSE: Ultrasound (US) allows non-invasive repeated assessments of diaphragmatic excursion (DE) and thickening fraction (DTF) at the bedside, reflecting diaphragmatic dysfunction (DD). We aimed at determining the prevalence and time-course of DD following elective thoracic surgery and the association with postoperative complications. MATERIAL AND METHODS: Prospective, single-centre, observational study with consecutive patients undergoing thoracic surgery. DE/DTF were measured by two observers blinded to each other at 3 different time-points: prior to surgery, immediately after extubation and on postoperative day 3. The changes in DE/DTF of both hemi-diaphragms over time were compared according to the side (operated/non-operated) using a two-way-ANOVA. The association with postoperative complications was assessed using logistic regression. RESULTS: Fifty patients, 60% males, aged 60 ± 15 years were included. Surgical procedures included lobectomy (n = 30), wedge-resection (n = 17) or pneumonectomy (n = 3). On the operated side, we observed a decrease in DE/DTF at D0 (-0.71 ± 0.12 mm, P < 0.05; -44 ± 30%, P < 0.05) and D3 (-0.82 ± 0.19 mm, P < 0.05; -39 ± 19%, P < 0.05) with respect to preoperative and non-operated side values over the study period. Persistent DD on the operated side was associated with an increased risk of lung infection (OR: 9.0, 95% CI [1.92-65.93], P = 0.001), ICU-admission (OR: 3.9, 95% CI [1.10-15.53], P = 0.04) according to univariate analysis and a prolonged length in hospital (OR: 1.3, 95% CI [1.1-1.7], P = 0.016) according to multivariate analysis. CONCLUSIONS: Thoracic surgery generates DD mainly observed on the operated side, which persists at least up to postoperative D3 and is associated with an increase in hospital stay.