International Practice Variation in Weaning Critically Ill Adults from Invasive Mechanical Ventilation.

RATIONALE: Randomized trials and meta-analyses have informed several aspects of weaning. Results are rarely replicated in practice, as evidence is applied in intensive care units that differ from the settings in which it was generated. OBJECTIVES: We aimed to: 1) describe weaning practice variation (identifying weaning candidates, conducting spontaneous breathing trials, using ventilator modes, and other aspects of care during weaning); 2) characterize regional differences in weaning practices; and 3) identify factors associated with practice variation. METHODS: We conducted a cross-sectional, self-administered, international postal survey of adult intensivist members of regional critical care societies from six geographic regions, including Canada, India, the United Kingdom, Europe, Australia/New Zealand, and the United States. We worked with societies to randomly select potential respondents from membership lists and administer questionnaires with the goal of obtaining 200 responses per region. RESULTS: We analyzed 1,144 questionnaires (Canada, 156; India, 136; United Kingdom, 219; Europe, 260; Australia/New Zealand, 196; United States, 177). Across regions, most respondents screened patients once daily to identify spontaneous breathing trials candidates (regional range, 70.0%-95.6%) and less often screened twice daily (range, 12.2%-33.1%) or more than twice daily (range, 1.6%-18.2%). To wean patients, most respondents used pressure support alone (range, 31.0%-71.7%) or with spontaneous breathing trials (range, 35.7%-68.1%). To conduct spontaneous breathing trials, respondents predominantly used pressure support with positive end-expiratory pressure (range, 56.5%-72.3%) and T-piece (8.9%-59.5%). Across regions, we found important variation in screening frequency, spontaneous breathing trials techniques; ventilator modes, written directives to guide care, noninvasive ventilation; and the roles played by available personnel in various aspects of weaning. CONCLUSIONS: Our findings document the presence and extent of practice variation in ventilator weaning on an international scale, and highlight the multidisciplinary and collaborative nature of weaning.

Cone-Photoreceptor Density in Adolescents With Type 1 Diabetes.

PURPOSE: Changes to retinal structure and function occur in individuals with diabetes before the onset of diabetic retinopathy. It is still unclear if these changes initially affect vascular or neural retina, or if particular retinal areas are more susceptible than others. This paper examines the distribution of cone photoreceptor density in the retina of adolescents with type 1 diabetes. METHODS: This cross-sectional prospective study includes 29 adolescents and young adults with type 1 diabetes and no diabetic retinopathy and 44 control participants recruited at the Hospital for Sick Children. Adaptive-optics enhanced retinal imaging of the cone photoreceptor mosaic was performed in four quadrants at an eccentricity of ∼7° from the fovea. After image registration and averaging, cone photoreceptors were counted and photoreceptor density was calculated. Analysis of variance with repeated measures was used to assess the differences in photoreceptor density between groups. RESULTS: Cone density was similar in both control participants and participants with diabetes. There was a small effect of retinal hemisphere; participants with diabetes did not show the expected radial asymmetry observed in control participants. CONCLUSIONS: Cone density in the parafoveal retina is not reduced in adolescents with type 1 diabetes.

Localizing functional damage in the neural retina of adolescents and young adults with type 1 diabetes.

PURPOSE: It is unknown which regions of the retina are most susceptible to damage by diabetes mellitus. We hypothesized that the standard and slow-flash (sf-) multifocal electroretinogram (mfERG) will localize retinal regions of greatest vulnerability. METHODS: A total of 55 adolescents and young adults with type 1 diabetes and without diabetic retinopathy (DR) or with mild nonproliferative DR and 54 typically-developing, age-similar control participants underwent mfERG and sf-mfERG testing. The amplitude and implicit time of the first order response of the standard mfERG and of three multifocal oscillatory potentials (mfOPs) of the sf-mfERG were compared between groups at the level of hexagons, quadrants, and rings using separate mixed model ANOVAs. Spatial mapping of the P values from post hoc pairwise comparisons illustrated patterns of retinal dysfunction. RESULTS: Delays in mfERG implicit times were evident across the tested retinal areas in the diabetes group. Delays in sf-mfERG implicit times were found at different eccentricities for each mfOP in the diabetes group. The greatest delays were noted in the periphery for mfOP1, in the midperiphery for mfOP2, and in the macular region for mfOP3. There were no significant group differences in amplitude for the mfERG and sf-mfERG protocols. CONCLUSIONS: Delays in mfERG and sf-mfERG responses suggest that the inner retina is particularly vulnerable to diabetes. Localizing regions of early dysfunction will help guide future studies to examine early structural damage associated with DR.

Research recruitment practices and critically ill patients. A multicenter, cross-sectional study (the Consent Study).

RATIONALE: Limited cross-sectional data exist to characterize the challenges of enrolling critically ill patients into research studies. OBJECTIVES: We aimed to describe recruitment practices, document factors that impact recruitment, and identify factors that may enhance future research feasibility. METHODS: We conducted a prospective, observational study of all critically ill adults eligible to participate in research studies at 23 Canadian intensive care units. We characterized eligibility events into one of five consent outcomes, identified reasons why opportunities to recruit were missed or infeasible, and documented decision maker's rationale for providing or declining consent. MEASUREMENTS AND MAIN RESULTS: Patients made decisions for themselves in 8.9% of encounters. In 452 eligibility events, consent was not required in 14 (3.1%), missed in 130 (28.8%), infeasible due to operational reasons in 129 (28.5%), obtained in 140 (31.0%), and declined in 39 (8.6%). More than half (57.3%) of all opportunities to recruit patients were missed or infeasible, largely because of research team workload, limited availability, narrow time windows for inclusion, difficulties in contacting families, nonexistent substitute decision makers (SDMs), physician refusals, and protocols prohibiting coenrollment. The rationale for providing consent differed between patients and SDMs. Greater research coordinator experience and site research volume and broader time windows for inclusion were significant predictors of fewer declined consents. CONCLUSIONS: A large gap exists between eligibility and the frequency with which consent encounters occur in intensive care unit research. Recruitment is susceptible to design and procedural inefficiencies that hinder recruitment and to personnel availability, given the need to interact with SDMs. Current enrollment practices may underrepresent potential study populations.

Participation of ICUs in critical care pandemic research: a province wide, cross-sectional survey.

OBJECTIVE: Little information exists to identify barriers to participation in pandemic research involving critically ill patients. We sought to characterize clinical research activity during the recent influenza A pandemic and to understand the experiences, beliefs, and practices of key stakeholders involved in pandemic research implementation. DESIGN: Cross-sectional, provincial postal questionnaire. SETTING: Level III ICUs. PARTICIPANTS: ICU administrators and research coordinators. MEASUREMENTS: We used rigorous survey methodology to identify potential respondents and to develop, test, and administer two-related questionnaires. MAIN RESULTS: We analyzed responses from 39 research coordinators and 139 administrators (response rates: 70.9% and 73.2%, respectively). Compared with non-influenza A studies, influenza A studies were less likely to be randomized trials and most often investigator-initiated and peer-review funded. Whereas both respondent groups felt that pandemic research would be helpful in providing care during future pandemics, research coordinators placed significantly greater importance on their ICU's participation in pandemic research. Both respondent groups expressed a need for rapid approval processes, designated funding for research personnel, adequate funding for start-up and patient screening, preapproved template protocols and consent forms, and clearer guidance regarding co-enrollment. Research coordinators acknowledged a need for alternative consent models to increase their capacity to participate in future pandemic research. More administrators expressed willingness to participate in the next pandemic if the required research resources were made available to them. CONCLUSIONS: Whereas research personnel and administrators support participation in pandemic ICU research, several modifiable barriers to participation exist. Pandemic research preparedness planning with regulatory bodies and dedicated funding to support research infrastructure, especially in community settings, are required to optimize future pandemic research participation.