Transparent decision support for mechanical ventilation using visualization of clinical preferences.

BACKGROUND: Systems aiding in selecting the correct settings for mechanical ventilation should visualize patient information at an appropriate level of complexity, so as to reduce information overload and to make reasoning behind advice transparent. Metaphor graphics have been applied to this effect, but these have largely been used to display diagnostic and physiologic information, rather than the clinical decision at hand. This paper describes how the conflicting goals of mechanical ventilation can be visualized and applied in making decisions. Data from previous studies are analyzed to assess whether visual patterns exist which may be of use to the clinical decision maker. MATERIALS AND METHODS: The structure and screen visualizations of a commercial clinical decision support system (CDSS) are described, including the visualization of the conflicting goals of mechanical ventilation represented as a hexagon. Retrospective analysis is performed on 95 patients from 2 previous clinical studies applying the CDSS, to identify repeated patterns of hexagon symbols. RESULTS: Visual patterns were identified describing optimal ventilation, over and under ventilation and pressure support, and over oxygenation, with these patterns identified for both control and support modes of mechanical ventilation. Numerous clinical examples are presented for these patterns illustrating their potential interpretation at the bedside. CONCLUSIONS: Visual patterns can be identified which describe the trade-offs required in mechanical ventilation. These may have potential to reduce information overload and help in simple and rapid identification of sub-optimal settings.

An Open-Loop, Physiologic Model-Based Decision Support System Can Provide Appropriate Ventilator Settings.

OBJECTIVES: To evaluate the physiologic effects of applying advice on mechanical ventilation by an open-loop, physiologic model-based clinical decision support system. DESIGN: Prospective, observational study. SETTING: University and Regional Hospitals' ICUs. PATIENTS: Varied adult ICU population. INTERVENTIONS: Advice were applied if accepted by physicians for a period of up to 4-8 hours. MEASUREMENTS AND MAIN RESULTS: Seventy-two patients were included for data analysis. Acceptance of advice was high with 95.7% of advice applied. In 41 patients in pressure support ventilation, following system advice led to significant decrease in PS, with PS reduced below 8 cm H2O in 15 patients (37%), a level not prohibiting extubation. Fraction of end-tidal CO2 values did not change, and increase in respiratory rate/VT was within clinical limits, indicating that in general, the system maintained appropriate patient breathing effort. In 31 patients in control mode ventilation, pressure control and tidal volume settings were decreased significantly, with tidal volume reduced below 8 mL/kg predicted body weight in nine patients (29%). Minute ventilation was maintained by a significant increase in respiratory rate. Significant reductions in FIO2 were seen on elevated baseline median values of 50% in both support and control mode-ventilated patients, causing clinically acceptable reductions in oxygen saturation. CONCLUSIONS: The results indicate that during a short period, the clinical decision support system provided appropriate suggestions of mechanical ventilation in a varied ICU population, significantly reducing ventilation to levels which might be considered safe and beneficial.

Restricting volumes of resuscitation fluid in adults with septic shock after initial management: the CLASSIC randomised, parallel-group, multicentre feasibility trial.

PURPOSE: We assessed the effects of a protocol restricting resuscitation fluid vs. a standard care protocol after initial resuscitation in intensive care unit (ICU) patients with septic shock. METHODS: We randomised 151 adult patients with septic shock who had received initial fluid resuscitation in nine Scandinavian ICUs. In the fluid restriction group fluid boluses were permitted only if signs of severe hypoperfusion occurred, while in the standard care group fluid boluses were permitted as long as circulation continued to improve. RESULTS: The co-primary outcome measures, resuscitation fluid volumes at day 5 and during ICU stay, were lower in the fluid restriction group than in the standard care group [mean differences -1.2 L (95 % confidence interval -2.0 to -0.4); p < 0.001 and -1.4 L (-2.4 to -0.4) respectively; p < 0.001]. Neither total fluid inputs and balances nor serious adverse reactions differed statistically significantly between the groups. Major protocol violations occurred in 27/75 patients in the fluid restriction group. Ischaemic events occurred in 3/75 in the fluid restriction group vs. 9/76 in the standard care group (odds ratio 0.32; 0.08-1.27; p = 0.11), worsening of acute kidney injury in 27/73 vs. 39/72 (0.46; 0.23-0.92; p = 0.03), and death by 90 days in 25/75 vs. 31/76 (0.71; 0.36-1.40; p = 0.32). CONCLUSIONS: A protocol restricting resuscitation fluid successfully reduced volumes of resuscitation fluid compared with a standard care protocol in adult ICU patients with septic shock. The patient-centred outcomes all pointed towards benefit with fluid restriction, but our trial was not powered to show differences in these exploratory outcomes. TRIAL REGISTRATION: NCT02079402.

Lower versus higher hemoglobin threshold for transfusion in septic shock.

BACKGROUND: Blood transfusions are frequently given to patients with septic shock. However, the benefits and harms of different hemoglobin thresholds for transfusion have not been established. METHODS: In this multicenter, parallel-group trial, we randomly assigned patients in the intensive care unit (ICU) who had septic shock and a hemoglobin concentration of 9 g per deciliter or less to receive 1 unit of leukoreduced red cells when the hemoglobin level was 7 g per deciliter or less (lower threshold) or when the level was 9 g per deciliter or less (higher threshold) during the ICU stay. The primary outcome measure was death by 90 days after randomization. RESULTS: We analyzed data from 998 of 1005 patients (99.3%) who underwent randomization. The two intervention groups had similar baseline characteristics. In the ICU, the lower-threshold group received a median of 1 unit of blood (interquartile range, 0 to 3) and the higher-threshold group received a median of 4 units (interquartile range, 2 to 7). At 90 days after randomization, 216 of 502 patients (43.0%) assigned to the lower-threshold group, as compared with 223 of 496 (45.0%) assigned to the higher-threshold group, had died (relative risk, 0.94; 95% confidence interval, 0.78 to 1.09; P=0.44). The results were similar in analyses adjusted for risk factors at baseline and in analyses of the per-protocol populations. The numbers of patients who had ischemic events, who had severe adverse reactions, and who required life support were similar in the two intervention groups. CONCLUSIONS: Among patients with septic shock, mortality at 90 days and rates of ischemic events and use of life support were similar among those assigned to blood transfusion at a higher hemoglobin threshold and those assigned to blood transfusion at a lower threshold; the latter group received fewer transfusions. (Funded by the Danish Strategic Research Council and others; TRISS ClinicalTrials.gov number, NCT01485315.).

Procalcitonin adds to diagnosis, but does not reduce initial antibiotics in febrile neutropenic children.

INTRODUCTION: The immune system is suppressed during chemotherapy. This makes diagnosis of severe life-threatening infections more difficult and it also intensifies the clinical course of such infections. Hence, empirical use of broad-spectrum antibiotics is mandatory. We investigated if procalcitonin (PCT) measurement may improve diagnostic accuracy. MATERIAL AND METHODS: In a prospective observational study, we included all admissions due to febrile episodes in a cohort of children below 16 years of age. PCT and C-reactive protein (CRP) were analyzed using LUMI test and VITROS CRP slides, respectively. RESULTS: We recorded 230 febrile episodes in 85 children. Severe systemic infection was found in 61 (27%) of these episodes. PCT performed better than CRP (p value ≤ 0.01). The discriminative power of PCT was significant already from admission. For CRP, discriminative power was significant after 48 hours. The cut-offs for PCT and CRP were 0.4 ng/ml and 336 nmol/ml to achieve sensitivities of 93%. The specificities for PCT and CRP were 45% and 22%, respectively. Severely infected patients were not found, either by PCT or by CRP in four (7%) cases. PCT levels rose in response to infection in the neutropenic population. CONCLUSION: PCT measurement considerably improves biochemical information; however, the sensitivity is too low to safely alter the recommended administration of empirical antibiotics at admission.