Frédérick D’Aragon

Genotype-guided versus standard vitamin K antagonist dosing algorithms in patients initiating anticoagulation. A systematic review and meta-analysis.

Variability in vitamin K antagonist (VKA) dosing is partially explained by genetic polymorphisms. We performed a meta-analysis to determine whether genotype-guided VKA dosing algorithms decrease a composite of death, thromboembolic events and major bleeding (primary outcome) and improve time in therapeutic range (TTR). We searched MEDLINE, EMBASE, CENTRAL, trial registries and conference proceedings for randomised trials comparing genotype-guided and standard (non genotype-guided) VKA dosing algorithms in adults initiating anticoagulation. Data were pooled using a random effects model. Of the 12 included studies (3,217 patients), six reported all components of the primary outcome of mortality, thromboembolic events and major bleeding (2,223 patients, 87 events). Our meta-analysis found no significant difference between groups for the primary outcome (relative risk 0.85, 95% confidence interval [CI] 0.54-1.34; heterogeneity Χ(²)=4.46, p=0.35, I(²)=10%). Based on 10 studies (2,767 patients), TTR was significantly higher in the genotype-guided group (mean difference (MD) 4.31%; 95% CI 0.35, 8.26; heterogeneity Χ(²)=43.31, p<0.001, I(²)=79%). Pre-specified exploratory analyses demonstrated that TTR was significantly higher when genotype-guided dosing was compared with fixed VKA dosing (6 trials, 997 patients: MD 8.41%; 95% CI 3.50,13.31; heterogeneity Χ(²)=15.18, p=0.01, I(²)=67%) but not when compared with clinical algorithm-guided dosing (4 trials, 1,770 patients: MD -0.29%; 95% CI -2.48,1.90; heterogeneity Χ(²)=1.53, p=0.68, I(²)=0%; p for interaction=0.002). In conclusion, genotype-guided compared with standard VKA dosing algorithms were not found to decrease a composite of death, thromboembolism and major bleeding, but did result in improved TTR. An improvement in TTR was observed in comparison with fixed VKA dosing algorithms, but not with clinical algorithms.

A systematic review of vasopressor blood pressure targets in critically ill adults with hypotension

PurposeClinicians must balance the risks from hypotension with the potential adverse effects of vasopressors. Experts have recommended a mean arterial pressure (MAP) target of at least 65 mmHg, and higher in older patients and in patients with chronic hypertension or atherosclerosis. We conducted a systematic review of randomized-controlled trials comparing higher vs lower blood pressure targets for vasopressor therapy administered to hypotensive critically ill patients.MethodsWe searched MEDLINE®, EMBASE™, and the Cochrane Central Register of Controlled Trials for studies of higher vs lower blood pressure targets for vasopressor therapy in critically ill hypotensive adult patients. Two reviewers independently assessed trial eligibility based on titles and abstracts, and they then selected full-text reports. Outcomes, subgroups, and analyses were prespecified. We used GRADE (Grading of Recommendations Assessment, Development and Evaluation) to rate the overall confidence in the estimates of intervention effects.ResultsOf 8001 citations, we retrieved 57 full-text articles and ultimately included two randomized-controlled trials (894 patients). Higher blood pressure targets were not associated with lower mortality (relative risk [RR], 1.05; 95% confidence interval [CI], 0.90 to 1.23; P = 0.54), and neither age (P = 0.17) nor chronic hypertension (P = 0.32) modified the overall effect. Nevertheless, higher blood pressure targets were associated with a greater risk of new-onset supraventricular cardiac arrhythmia (RR, 2.08; 95% CI, 1.28 to 3.38; P < 0.01).ConclusionCurrent evidence does not support a MAP target > 70 mmHg in hypotensive critically ill adult patients requiring vasopressor therapy.RésuméObjectifLes cliniciens doivent équilibrer les risques liés à l’hypotension aux complications potentielles des vasopresseurs. Des experts ont recommandé de cibler une tension artérielle moyenne (TAM) d’au moins 65 mmHg, et une TAM plus élevée chez les patients atteints d’hypertension chronique, d’athérosclérose ou plus âgés. Nous avons réalisé une revue systématique des études randomisées contrôlées comparant des cibles de tension artérielle plus élevées à plus basses chez des patients hypotendus en état critique recevant un traitement vasopresseur.MéthodeNous avons fait des recherches dans les bases de données Medline, EMBASE et dans le registre central des études contrôlées Cochrane afin d’en extraire les études comparant des cibles de tension artérielle plus élevées ou plus basses chez des patients adultes hypotendus et en état critique recevant un traitement vasopresseur. Deux examinateurs ont évalué de façon indépendante l’éligibilité des études selon leur titre et leur résumé, puis sélectionné les articles intégraux. Les critères d’évaluation, sous-groupes et analyses étaient spécifiés au préalable. Nous avons utilisé le système GRADE (Grading of Recommendations Assessment, Development and Evaluation) afin d’évaluer la confiance globale dans les estimations des effets de l’intervention.RésultatsParmi les 8001 citations, nous avons extrait 57 articles intégraux et finalement inclus deux études randomisées contrôlées (894 patients). Les cibles de tension artérielle plus élevées n’étaient pas associées à une mortalité plus basse (risque relatif [RR] 1,05; intervalle de confiance [IC] 95 %, 0,90 à 1,23; P = 0,54), et ni l’âge (P = 0,17) ni l’hypertension chronique (P = 0,32) n’ont modifié l’effet global. Cependant, les cibles de tension artérielle plus élevées étaient associées à un risque plus élevé de nouvelle apparition d’une arythmie cardiaque supraventriculaire (RR, 2,08; IC 95 %, 1,28 à 3,38; P < 0,01).ConclusionLes données probantes actuelles n’appuient pas une cible de TAM supérieure à 70 mmHg chez les patients adultes hypotendus et gravement malades nécessitant un traitement vasopresseur.

Fluids in Sepsis and Septic Shock (FISSH): protocol for a pilot randomised controlled trial

Introduction Observational evidence suggests physiological benefits and lower mortality with lower chloride solutions; however, 0.9% saline remains the most widely used fluid worldwide. Given uncertainty regarding the association of lower chloride on mortality, it is unlikely that practice will change without direct randomised clinical trial (RCT) evidence. This pilot RCT will investigate the feasibility of a large-scale trial directly comparing low chloride with high chloride fluids in patients with septic shock. Methods and analysis This is a randomised, concealed, blinded parallel-group multicentre pilot trial. We will include adult critically ill patients with septic shock, defined as ongoing hypotension despite 1 L of fluid, or a serum lactate >4 mmol/L, who are within 6 hours of hospital presentation or rapid response team activation. We will exclude patients if they have an aetiology of shock other than sepsis, if they have acute burn injury, elevated intracranial pressure, intent to withdraw life support or previous enrolment in this or a competing trial. Following informed consent, patients will be randomised to a low chloride fluid strategy or a high chloride fluid strategy for the duration of their ICU stay or until 30 days postrandomisation. Clinicians, patients, families and research staff will be blinded. The primary outcome for this trial will be feasibility, assessed by consent rate, recruitment success and protocol adherence. Patient-important clinical outcomes include mortality, receipt of renal replacement therapy, intensive care unit and hospital lengths of stay and surrogate outcomes of incidence of acidosis, hyperkalaemia and acute kidney injury. Ethics and dissemination This pilot trial will test the feasibility of conducting the main trial, which will examine the effect of high versus low chloride fluids in patients with septic shock on patient-important outcomes. Trial registration number NCT02748382, registered 8 April 2016. Protocol date 1 July 2016.

Early vasopressor use following traumatic injury: a systematic review

Objectives Current guidelines suggest limiting the use of vasopressors following traumatic injury; however, wide variations in practice exist. Although excessive vasoconstriction may be harmful, these agents may help reduce administration of potentially harmful resuscitation fluids. This systematic review aims to compare early vasopressor use to standard resuscitation in adults with trauma-induced shock. Design Systematic review. Data sources We searched MEDLINE, EMBASE, ClinicalTrials.gov and the Central Register of Controlled Trials from inception until October 2016, as well as the proceedings of 10 relevant international conferences from 2005 to 2016. Eligibility criteria for selecting studies Randomised controlled trials and controlled observational studies that compared the early vasopressor use with standard resuscitation in adults with acute traumatic injury. Results Of 8001 citations, we retrieved 18 full-text articles and included 6 studies (1 randomised controlled trial and 5 observational studies), including 2 published exclusively in abstract form. Across observational studies, vasopressor use was associated with increased short-term mortality, with unadjusted risk ratios ranging from 2.31 to 7.39. However, the risk of bias was considered high in these observational studies because patients who received vasopressors were systematically sicker than patients treated without vasopressors. One clinical trial (n=78) was too imprecise to yield meaningful results. Two clinical trials are currently ongoing. No study measured long-term quality of life or cognitive function. Conclusions Existing data on the effects of vasopressors following traumatic injury are of very low quality according to the Grading of Recommendations, Assessment, Development and Evaluation methodology. With emerging evidence of harm associated with aggressive fluid resuscitation and, in selected subgroups of patients, with permissive hypotension, the alternatives to vasopressor therapy are limited. Observational data showing that vasopressors are part of usual care would provide a strong justification for high-quality clinical trials of early vasopressor use during trauma resuscitation. Trial registration number CRD42016033437.

The Deferred Consent Model in a Prospective Observational Study Evaluating Myocardial Injury in the Intensive Care Unit

Background: Informed consent is a hallmark of ethical clinical research. An inherent challenge in critical care research is obtaining consent when patients lack decision-making capacity. One solution is deferred consent, which is often used for studies that are low risk or involve emergency interventions. Our objective was to describe a deferred consent model in a low-risk critical care study. Methods: Prognostic Value of Elevated Troponins in Critical Illness Study was a prospective, pilot observational study of critically ill patients in 3 intensive care units, involving serial electrocardiograms and cardiac biomarkers. Newly admitted patients were enrolled over 1 month. When possible, informed consent was obtained a priori from the patient or substitute decision maker (SDM); otherwise, consent was deferred until the patient regained consent capacity or until their SDM was available. Logistic regression analysis was used to determine the association between patient’s sex, Acute Physiology and Chronic Health Evaluation II score, study center, person providing consent (patient vs SDM), method of consent (telephone vs in person), and the provision or not of informed consent. Results: The overall consent rate was 80.1% (213 of 266 persons approached). Of the 53 persons declining consent, 37 (69.8%) agreed to the use of data collected up until that point. Over half of all consent encounters were with patients rather than SDMs. Median interval delay between enrollment and the consent encounter was 1 day. On multivariate analysis, the only variable associated with consent was male sex of the patient (odds ratio for males 2.59, confidence interval: 1.19-5.63). Conclusion: Deferred consent facilitates implementation of time-sensitive research protocols until a consent encounter is possible. As a feasible alternative to exclusive a priori consent, the deferred consent model can be useful in low-risk studies in critically ill patients.

201: VASOPRESSIN USE IN DONORS AFTER CARDIAC DEATH

Critical Care Medicine • Volume 46 • Number 1 (Supplement) www.ccmjournal.org Learning Objectives: Vasopressin therapy can address specific pathophysiological effects of brain death, however, the efficacy and safety of vasopressin in donors after cardiac death (DCD) has not been studied. The purpose of this study was to investigate vasopressin use in DCD in the eight first centres participating in the Canada-DONATE National Cohort Study. Methods: This 12-month prospective, observational study in 11 ICUs included consecutive consented adult deceased organ donors. Data for this analysis were obtained from hospital records retrospectively from one day prior to consent and then prospectively up to the time of organ recovery. Reasons for vasopressin initiation were not recorded. We report descriptive statistics for current practices regarding vasopressin administration. Comparisons were made using non-parametric methods. Results: There were 74 DCD donors enrolled, from which 12 received vasopressin (16.2%). The principal diagnosis leading to organ donation was anoxic brain injury (31.1%). Although nonstatistically significant, DCD donors who received vasopressin had more traumatic brain injuries 25% vs 14.5% (p = 0.4). Vasopressin doses ranged from 1.2–2.4 u/h. All patients who received vasopressin were also co-administered norepinephrine. There were no significant differences between DCD donors administered vasopressin and those who were not in age (49 years; SD = 13.1 vs 54.8 years; SD = 13.1, p = 0.2) or gender (male: 58.3% vs 31.3%, p = 1.0). DDAVP was coadministered with vasopressin in 16.7% of patients while only 4.8% of non-exposed patients received DDAVP (p = 0.18). The rate of kidney recovery for patients receiving vasopressin was 58.33% and 49.09% for those who had not. Conclusions: This study illustrates that the administration of vasopressin in DCD is not uncommon. Currently, no literature exists concerning this practice. The final results of the National Cohort Study should permit us to identify predictors of vasopressin use and investigate its efficacy in DCD donors. 201

Canadian Critical Care Society revised process for guideline development and endorsement

To the Editor, Clinical practice guidelines (CPGs) are ‘‘statements that include recommendations intended to optimize patient care that are informed by a systematic review of evidence and an assessment of the benefits and harms of alternative care options’’. Healthcare workers struggle to keep up with rapidly evolving scientific literature. In theory, CPGs constitute a comprehensive overview of the best available evidence addressing a specific clinical question and take into account considerations such as certainty in the evidence, patients’ values and preferences, and resource use or cost. These factors are used to generate actionable and trustworthy recommendations, which may inform clinician-patient discussions and shared decision-making. Reducing the gap between scientific evidence and actual practice may improve the safety and efficiency of healthcare interventions. In contrast, failure to adhere to these high standards when developing guidelines may lead to erroneous conclusions. In 2011, the Institute of Medicine published standards for the development of ‘‘Trustworthy Guidelines’’, classified by the following domains: 1) the clinical

Atraumatic (pencil-point) versus conventional needles for lumbar puncture: a clinical practice guideline

### What you need to know Is the needle tip configuration important when performing a lumbar puncture for any indication? A systematic review published in the Lancet in December 2017 suggests that it is. The review found that using atraumatic (pencil-point) lumbar puncture needles instead of conventional lumbar puncture needles reduced the risk of post-dural-puncture headache and of return to hospital for additional pain control.1 This guideline recommendation aims to promptly and transparently translate this evidence to a clinical recommendation, following standards for GRADE methodology and trustworthy guidelines.2 The BMJ Rapid Recommendations panel makes a strong recommendation for the use of atraumatic needles for lumbar puncture in all patients regardless of age (adults and children) or indication instead of conventional needles.34 Box 1 shows the article and evidence linked to this Rapid Recommendation. The main infographic provides an overview of the absolute benefits and harms (although none were present here) of atraumatic needles. Table 1 below shows any evidence that has emerged since the publication of this guideline. Box 1 ### Linked resources for this BMJ Rapid Recommendations clusterRETURN TO TEXT

Vasopressor use following traumatic injury – A single center retrospective study

Objectives Vasopressors are not recommended by current trauma guidelines, but recent reports indicate that they are commonly used. We aimed to describe the early hemodynamic management of trauma patients outside densely populated urban centers. Methods We conducted a single-center retrospective cohort study in a Canadian regional trauma center. All adult patients treated for traumatic injury in 2013 who died within 24 hours of admission or were transferred to the intensive care unit were included. A systolic blood pressure <90 mmHg, a mean arterial pressure <60 mmHg, the use of vasopressors or ≥2 L of intravenous fluids defined hemodynamic instability. Main outcome measures were use of intravenous fluids and vasopressors prior to surgical or endovascular management. Results Of 111 eligible patients, 63 met our criteria for hemodynamic instability. Of these, 60 (95%) had sustained blunt injury and 22 (35%) had concomitant severe traumatic brain injury. The subgroup of patients referred from a primary or secondary hospital (20 of 63, 32%) had significantly longer transport times (243 vs. 61 min, p<0.01). Vasopressors, used in 26 patients (41%), were independently associated with severe traumatic brain injury (odds ratio 10.2, 95% CI 2.7–38.5). Conclusions In this cohort, most trauma patients had suffered multiple blunt injuries. Patients were likely to receive vasopressors during the early phase of trauma care, particularly if they exhibited signs of neurologic injury. While these results may be context-specific, determining the risk-benefit trade-offs of fluid resuscitation, vasopressors and permissive hypotension in specific patients subgroups constitutes a priority for trauma research going forwards.

Canada-DONATE study protocol: a prospective national observational study of the medical management of deceased organ donors

Introduction Research on the management of deceased organ donors aims to improve the number and quality of transplants and recipient outcomes. In Canada, this research is challenged by regionalisation of donation services within provinces and the geographical, clinical and administrative separation of donation from transplantation services. This study aims to build a national platform for future clinical trials in donor management. Objectives are to engage collaborators at donation hospitals and organ donation organisations (ODOs) across Canada, describe current practices, evaluate the effectiveness of donation-specific interventions and assess the feasibility of future clinical trials. Methods and analysis This ongoing prospective observational study of the medical management of deceased organ donors will enrol more than 650 consented potential donors from adult intensive care units at 33 hospital sites across Canada, each participating for 12 months. ODOs ensure enrolment of consecutive eligible participants. Research staff record detailed data about participants, therapies, organ assessments, death declaration procedures and adverse clinical exposures from the time of donation consent to organ recovery. ODOs provide reasons that organs are declined, dates and places of transplantation, and recipient age and sex. Descriptive analyses will summarise current practices. Effectiveness analyses will examine donation-specific interventions with respect to the number of transplants, using multilevel regression models to account for clustering by donor, hospitals and ODOs. Feasibility analyses will focus on acceptance of the research consent model; participation of academic and community hospitals as well as ODOs; and accessibility of recipient data. Ethics and dissemination This study uses a waiver of research consent. Hospitals will receive reports on local practices benchmarked to (1) national practices and (2) national donor management guidelines. We will report findings to donation and transplant collaborators (ie, clinicians, researchers, ODOs) and publish in peer-reviewed journals. Trial registration number NCT03114436.