Effect of level of sedation on outcomes in critically ill adult patients: a systematic review of clinical trials with meta-analysis and trial sequential analysis

Background

Sedation is routinely administered to critically ill patients to alleviate anxiety, discomfort, and patient-ventilator asynchrony. However, it must be balanced against risks such as delirium and prolonged intensive care stays. This study aimed to investigate the effects of different levels of sedation in critically ill adults.

Methods

Systematic review with meta-analysis and trial sequential analysis (TSA) of randomised clinical trials including critically ill adults admitted to the intensive care unit. CENTRAL, MEDLINE, Embase, LILACS, and Web of Science were searched from their inception to 13 June 2023. Risks of bias were assessed using the Cochrane risk of bias tool. Primary outcome was all-cause mortality. Aggregate data were synthesised with meta-analyses and TSA, and the certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. This study is registered with PROSPERO: CRD42023386960.

Findings

Fifteen trials randomising 4352 patients were included, of which 13 were assessed high risk of bias. Meta-analyses comparing lighter to deeper sedation showed no evidence of a difference in all-cause mortality (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.83-1.06; p = 0.28; 15 trials; moderate certainty evidence), serious adverse events (RR 0.99, CI 0.92-1.06; p = 0.80; 15 trials; moderate certainty evidence), or delirium (RR 1.01, 95% CI 0.94-1.09; p = 0.78; 11 trials; moderate certainty evidence). TSA showed that when assessing mortality, a relative risk reduction of 16% or more between the compared interventions could be rejected.

Interpretation

The level of sedation has not been shown to affect the risks of death, delirium, and other serious adverse events in critically ill adult patients. While TSA suggests that additional trials are unlikely to significantly change the conclusion of the meta-analyses, the certainty of evidence was moderate. This suggests a need for future high-quality studies with higher methodological rigor.

Funding

None.

The impact of frailty and rapid response team activation on patients admitted to the intensive care unit: A case-control matched, observational, single-centre cohort study

BACKGROUND

Frailty is a multi-dimensional syndrome associated with mortality and adverse outcomes in patients admitted to the intensive care unit (ICU). Further investigation is warranted to explore the interplay among factors such as frailty, clinical deterioration triggering a medical emergency team (MET) review, and outcomes following admission to the ICU.

METHODS

Single-centre, retrospective observational case-control study of adult patients (>18 years) admitted to a medical-surgical ICU with (cases) or without (controls) a preceding MET review between 4 h and 14 days prior. Matching was performed for age, ICU admission diagnosis, Acute Physiology and Chronic Health Evaluation III (APACHE III) score and the 8-point Clinical Frailty Scale (CFS). Cox proportional hazard regression modelling was performed to determine associations with 30-day mortality after admission to ICU.

RESULTS

A total of 2314 matched admissions were analysed. Compared to non-frail patients (CFS 1-4), mortality was higher in all frail patients (CFS 5-8), at 31% vs. 13%, and in frail patients admitted after MET review at 33%. After adjusting for age, APACHE, antecedent MET review and CFS in the Cox regression, mortality hazard ratio increased by 26% per CFS point and by 3% per APACHE III point, while a MET review was not an independent predictor. Limitations of medical treatment occurred in 30% of frail patients, either with or without a MET antecedent, and this was five times higher compared to non-frail patients.

CONCLUSION

Frail patients admitted to ICU have a high short-term mortality. An antecedent MET event was associated with increased mortality but did not independently predict short-term survival when adjusting for confounding factors. The intrinsic significance of frailty should be primarily considered during MET review of frail patients. This study suggests that routine frailty assessment of hospitalised patients would be helpful to set goals of care when admission to ICU could be considered.

Protracted fibrinolysis resistance following cardiac surgery with cardiopulmonary bypass: A prospective observational study of clinical associations and patient outcomes

BACKGROUND

Surgery on cardiopulmonary bypass (CPB) elicits a pleiomorphic systemic host response which, when severe, requires prolonged intensive care support. Given the substantial cross-talk between inflammation, coagulation, and fibrinolysis, the aim of this hypothesis-generating observational study was to document the kinetics of fibrinolysis recovery post-CPB using ClotPro® point-of-care viscoelastometry. Tissue plasminogen activator-induced clot lysis time (TPA LT, s) was correlated with surgical risk, disease severity, organ dysfunction and intensive care length of stay (ICU LOS).

RESULTS

In 52 patients following CPB, TPA LT measured on the first post-operative day (D1) correlated with surgical risk (EuroScore II, Spearman's rho .39, p < .01), time on CPB (rho = .35, p = .04), disease severity (APACHE II, rho = .52, p < .001) and organ dysfunction (SOFA, rho = .51, p < .001) scores, duration of invasive ventilation (rho = .46, p < .01), and renal function (eGFR, rho = -.65, p < .001). In a generalized linear regression model containing TPA LT, CPB run time and markers of organ function, only TPA LT was independently associated with the ICU LOS (odds ratio 1.03 [95% CI 1.01-1.05], p = .01). In a latent variables analysis, the association between TPA LT and the ICU LOS was not mediated by renal function and thus, by inference, variation in the clearance of intraoperative tranexamic acid.

CONCLUSIONS

This observational hypothesis-generating study in patients undergoing cardiac surgery with cardiopulmonary bypass demonstrated an association between the severity of fibrinolysis resistance, measured on the first post-operative day, and the need for extended postoperative ICU level support. Further examination of the role of persistent fibrinolysis resistance on the clinical outcomes in this patient cohort is warranted through large-scale, well-designed clinical studies.

Frailty in the prediction of delirium in the intensive care unit: A secondary analysis of the Deli study

BACKGROUND

Delirium is an acute disorder of attention and cognition with an incidence of up to 70% in the adult intensive care setting. Due to the association with significantly increased morbidity and mortality, it is important to identify who is at the greatest risk of an acute episode of delirium while being cared for in the intensive care. The objective of this study was to determine the ability of the cumulative deficit frailty index and clinical frailty scale to predict an acute episode of delirium among adults admitted to the intensive care.

METHODS

This study is a secondary analysis of the Deli intervention study, a hybrid stepped-wedge cluster randomized controlled trial to assess the effectiveness of a nurse-led intervention to reduce the incidence and duration of delirium among adults admitted to the four adult intensive care units in the south-west of Sydney, Australia. Important predictors of delirium were identified using a bootstrap approach and the absolute risks, based on the cumulative deficit frailty index and the clinical frailty scale are presented.

RESULTS

During the 10-mth data collection period (May 2019 and February 2020) 2566 patients were included in the study. Both the cumulative deficit frailty index and the clinical frailty scale on admission, plus age, sex, and APACHE III (AP III) score were able to discriminate between patients who did and did not experience an acute episode of delirium while in the intensive care, with AUC of 0.701 and 0.703 (moderate discriminatory ability), respectively. The addition of a frailty index to a prediction model based on age, sex, and APACHE III score, resulted in net reclassified of risk. Nomograms to individualize the absolute risk of delirium using these predictors are also presented.

CONCLUSION

We have been able to show that both the cumulative deficits frailty index and clinical frailty scale predict an acute episode of delirium among adults admitted to intensive care.

Furosemide versus placebo for fluid overload in intensive care patients-The randomised GODIF trial second version: Statistical analysis plan

BACKGROUND

Fluid overload is associated with increased mortality in intensive care unit (ICU) patients. The GODIF trial aims to assess the benefits and harms of fluid removal with furosemide versus placebo in stable adult patients with moderate to severe fluid overload in the ICU. This article describes the detailed statistical analysis plan for the primary results of the second version of the GODIF trial.

METHODS

The GODIF trial is an international, multi-centre, randomised, stratified, blinded, parallel-group, pragmatic clinical trial, allocating 1000 adult ICU patients with moderate to severe fluid overload 1:1 to furosemide versus placebo. The primary outcome is days alive and out of hospital within 90 days post-randomisation. With a power of 90% and an alpha level of 5%, we may reject or detect an improvement of 8%. The primary analyses of all outcomes will be performed in the intention-to-treat population. For the primary outcome, the Kryger Jensen and Lange method will be used to compare the two treatment groups adjusted for stratification variables supplemented with sensitivity analyses in the per-protocol population and with further adjustments for prognostic variables. Secondary outcomes will be analysed with multiple linear regressions, logistic regressions or the Kryger Jensen and Lange method as suitable with adjustment for stratification variables.

CONCLUSION

The GODIF trial data will increase the certainty about the effects of fluid removal using furosemide in adult ICU patients with fluid overload.

TRIAL REGISTRATIONS

EudraCT identifier: 2019-004292-40 and ClinicalTrials.org: NCT04180397.

Capnodynamic monitoring of lung volume and pulmonary blood flow during alveolar recruitment: a prospective observational study in postoperative cardiac patients

Alveolar recruitment manoeuvres may mitigate ventilation and perfusion mismatch after cardiac surgery. Monitoring the efficacy of recruitment manoeuvres should provide concurrent information on pulmonary and cardiac changes. This study in postoperative cardiac patients applied capnodynamic monitoring of changes in end-expiratory lung volume and effective pulmonary blood flow. Alveolar recruitment was performed by incremental increases in positive end-expiratory pressure (PEEP) to a maximum of 15 cmH2O from a baseline of 5 cmH2O over 30 min. The change in systemic oxygen delivery index after the recruitment manoeuvre was used to identify responders (> 10% increase) with all other changes (≤ 10%) denoting non-responders. Mixed factor ANOVA using Bonferroni correction for multiple comparisons was used to denote significant changes (p < 0.05) reported as mean differences and 95% CI. Changes in end-expiratory lung volume and effective pulmonary blood flow were correlated using Pearson's regression. Twenty-seven (42%) of 64 patients were responders increasing oxygen delivery index by 172 (95% CI 61-2984) mL min-1 m-2 (p < 0.001). End-expiratory lung volume increased by 549 (95% CI 220-1116) mL (p = 0.042) in responders associated with an increase in effective pulmonary blood flow of 1140 (95% CI 435-2146) mL min-1 (p = 0.012) compared to non-responders. A positive correlation (r = 0.79, 95% CI 0.5-0.90, p < 0.001) between increased end-expiratory lung volume and effective pulmonary blood flow was only observed in responders. Changes in oxygen delivery index after lung recruitment were correlated to changes in end-expiratory lung volume (r = 0.39, 95% CI 0.16-0.59, p = 0.002) and effective pulmonary blood flow (r = 0.60, 95% CI 0.41-0.74, p < 0.001). Capnodynamic monitoring of end-expiratory lung volume and effective pulmonary blood flow early in postoperative cardiac patients identified a characteristic parallel increase in both lung volume and perfusion after the recruitment manoeuvre in patients with a significant increase in oxygen delivery.Trial registration This study was registered on ClinicalTrials.gov (NCT05082168, 18th of October 2021).

Volume responsiveness revisited: an observational multicenter study of continuous versus binary outcomes combining echocardiography and venous return physiology

Echocardiography can assess cardiac preload when fluid administration is used to treat acute circulatory failure. Changes in stroke volume (SV) are inherently a continuous phenomenon relating to the pressure gradient for venous return (VRdP). However, most clinical studies have applied a binary definition based on a fractional change in SV. This study tested the hypothesis that calculating the analog mean systemic filling pressure (Pmsa) and VRdP would enhance echocardiography to describe SV responses to a preload challenge. We investigated 540 (379 males) patients during a standardized passive leg raising (PLR) maneuver. Patients were further categorized by the presence of impaired right ventricular function (impRV) or increased intra-abdominal hypertension (IAH). Multivariable linear regression identified VRdP (partial r = -0.26, P < 0.001), ventilatory-induced variations in superior vena cava diameter (partial r = 0.43, P < 0.001), and left ventricular outflow tract maximum-Doppler velocity (partial r = 0.13, P < 0.001) as independent variables associated with SV changes. The model explained 38% (P < 0.001) of the SV change in the whole cohort and 64% (P < 0.001) when excluding patients with impRV or IAH. The correlation between Pmsa or VRdP and SV changes lost statistical significance with increasing impRV or IAH. A binary definition of volume responsiveness (>10% increase in SV) generated an area under the curve of 0.79 (P < 0.001) in logistic regression but failed to identify Pmsa or VRdP as independent variables and overlooked the confounding influence of impRV and IAH. In conclusion, venous return physiology may enhance echocardiographic assessments of volume responsiveness, which should be based on continuous changes in stroke volume.NEW & NOTEWORTHY The analog mean systemic filling pressure and the pressure gradient for venous return combined with echocardiography predict continuous changes in stroke volume following a passive leg raising maneuver. The confounding effects of impaired right ventricular function and increased intra-abdominal pressure can be identified. Using a binary cutoff for the fractional change in stroke volume, common in previous clinical research, fails to identify the importance of variables relevant to venous return physiology and confounding conditions.

A randomised trial of intracavitary electrocardiography versus surface landmark measurement for central venous access device placement

BACKGROUND

Malpositioned central venous access devices (CVADs) can lead to significant patient injury including central vein thrombosis and dysrhythmias. Intra-cavitary electrocardiography (IC ECG) has been recommended by peak professional bodies as an accurate alternative for bedside CVAD insertion, to reduce risk of malposition and allowing immediate use of the device. Our objective was to compare the effect of IC ECG on CVAD malposition compared to traditional institutional practice for CVAD placement.

METHODS

Randomised controlled trial of IC ECG CVAD insertion verses traditional CVAD insertion (surface landmark measurement with post insertion x ray). Patient recruitment was from December 2016 to July 2018. The setting was a 900-bed tertiary referral hospital based in South Western Sydney, Australia. Three hundred and forty-four adult patients requiring CVAD insertion for intravenous therapy, were enrolled and randomly allocated (1:1 ratio) to either IC-ECG (n = 172) or traditional (n = 172) CVAD insertion. Our primary outcome of interest was the rate of catheters not requiring repositioning after insertion (ready for use). Secondary outcomes were comparison of procedure time and cost.

RESULTS

Of the 172 patients allocated to the IC ECG method, 170 (99%) were ready for use immediately compared to 139 of the 172 (81%) in the traditional insertion group (difference, 95% confidence interval (CI): 18%, 11.9-24.1%). The total procedure time was mean 15 min (SD 8 min) for IC ECG and mean 36 min (SD 17 min) for traditional CVAD insertion (difference-19.9 min (95% CI-14.6 to -34.4). IC ECG guided CVAD insertion had a cost reduction of AUD $62.00 per procedure.

CONCLUSIONS

Using IC-ECG resulted in nearly no requirement for post-insertion repositioning of CVADs resulting in savings in time and cost and virtually eliminating the need for radiographic confirmation.

TRIAL REGISTRATION

This trial is registered at the Australian New Zealand Clinical Trials Registry (http://www.anzctr.org.au). The registration number is ACTRN12620000919910.

Radiological appearance and lung function six months after invasive ventilation in ICU for COVID-19 pneumonia: An observational follow-up study

BACKGROUND

Respiratory functional sequelae in COVID-19 patients admitted to the intensive care unit for invasive ventilation are sparsely reported. The aim of this study was to investigate the radiological lung appearance, lung function and their association at 6 months after hospital discharge. It was hypothesized that the degree of pathological morphology on CT scans would correlate with lung function at the time of follow-up.

METHODS AND FINDINGS

In this single-centre prospective observational study, 86 from 154 patients admitted to ICU due to COVID-19 between March 2020 and May 2021 were followed up at 6 months post discharge with computed tomography (CT) of the chest and pulmonary function tests (PFTs). The PFT results were expressed as z-scores calculated as the difference between the measured and predicted values divided by the standard deviation obtained from a reference population. Correlations were evaluated by Spearman's rho including the 95% confidence interval. Pathological changes on CT were found in 78/85 participants with fibrous parenchymal bands being the most prevalent finding (91%) followed by traction bronchiectasis (64%) and ground glass opacities (41%). Sixty-five participants performed PFTs, and a restrictive pattern was the most prevalent abnormality (34%). Diffusing capacity of the lung for carbon monoxide (DLCO) was reduced in 66% of participants. The CT severity score weakly correlated with forced vital capacity (FVC) z-score (0.295, p = 0.006), DLCO z-score (-0.231, p = 0.032) and alveolar volume (VA) z-score (0.253, p = 0.019).

CONCLUSIONS

Most patients showed persistent radiological abnormalities on CT and reduced lung volumes, impaired diffusion capacity and patterns of restrictive lung function at 6 months post discharge from the ICU. The correlations between abnormalities on CT and lung function tests were weak. Further, studies with a long-term follow-up of lung function in this group of patients are needed.

Atrial Fibrillation (AFIB) in the ICU: Incidence, Risk Factors, and Outcomes: The International AFIB-ICU Cohort Study

OBJECTIVES

To assess the incidence, risk factors, and outcomes of atrial fibrillation (AF) in the ICU and to describe current practice in the management of AF.

DESIGN

Multicenter, prospective, inception cohort study.

SETTING

Forty-four ICUs in 12 countries in four geographical regions.

SUBJECTS

Adult, acutely admitted ICU patients without a history of persistent/permanent AF or recent cardiac surgery were enrolled; inception periods were from October 2020 to June 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We included 1,423 ICU patients and analyzed 1,415 (99.4%), among whom 221 patients had 539 episodes of AF. Most (59%) episodes were diagnosed with continuous electrocardiogram monitoring. The incidence of AF was 15.6% (95% CI, 13.8-17.6), of which newly developed AF was 13.3% (11.5-15.1). A history of arterial hypertension, paroxysmal AF, sepsis, or high disease severity at ICU admission was associated with AF. Used interventions to manage AF were fluid bolus 19% (95% CI 16-23), magnesium 16% (13-20), potassium 15% (12-19), amiodarone 51% (47-55), beta-1 selective blockers 34% (30-38), calcium channel blockers 4% (2-6), digoxin 16% (12-19), and direct current cardioversion in 4% (2-6). Patients with AF had more ischemic, thromboembolic (13.6% vs 7.9%), and severe bleeding events (5.9% vs 2.1%), and higher mortality (41.2% vs 25.2%) than those without AF. The adjusted cause-specific hazard ratio for 90-day mortality by AF was 1.38 (95% CI, 0.95-1.99).

CONCLUSIONS

In ICU patients, AF occurred in one of six and was associated with different conditions. AF was associated with worse outcomes while not statistically significantly associated with 90-day mortality in the adjusted analyses. We observed variations in the diagnostic and management strategies for AF.

The effect of ketamine and fentanyl on haemodynamics during intubation in pre-hospital and retrieval medicine

BACKGROUND

Ketamine use for rapid sequence intubation (RSI) is frequent in pre-hospital and retrieval medicine (PHARM) and is associated with potentially deleterious haemodynamic changes, which may be ameliorated by concurrent use of fentanyl.

OBJECTIVES

To describe the frequency with which fentanyl is used in conjunction with ketamine in a system where its use is discretionary, and to explore any observed changes in haemodynamics with its use.

METHODS

A retrospective observational study of over 800 patients undergoing RSI with ketamine ± fentanyl in the PHARM setting between 2015 and 2019. The primary outcome was the proportion of patients in each group who had a systolic blood pressure (SBP) outside a pre-specified target range, with adjustment for baseline abnormality, within 10 min of anaesthetic induction.

RESULTS

Eight hundred and seventy-six patients were anaesthetised with ketamine, of whom 804 were included in the analysis. 669 (83%, 95% CI 80%-86%) received ketamine alone, and 135 (17%, 95% CI 14%-20%) received both fentanyl and ketamine. Median fentanyl dose was 1.1 mcg/kg (IQR 0.75-1.5 mcg/kg). Systolic blood pressure (SBP) at induction was consistently associated with SBP after intubation in multivariable logistic regression, but fentanyl use was not associated with a change in odds of meeting the primary outcome (OR 1.08; 95% CI 0.72-1.60), becoming hypertensive (OR 1.35; 95% CI 0.88-2.07) or hypotensive (OR 0.76; 95% CI 0.47-1.21).

CONCLUSIONS

The addition of fentanyl to ketamine for RSI was not associated with an alteration of the odds of post-induction haemodynamic stability, although the doses used were low. These findings justify further study into the optimal dosing of fentanyl during RSI in pre-hospital and retrieval medicine.

Mechanical ventilation post-bilateral lung transplantation: A scoping review

BACKGROUND

Evidence from lung protective ventilation (LPV) in the acute respiratory distress syndrome has commonly been applied to guide periprocedural ventilation in lung transplantation. However, this approach may not adequately consider the distinctive features of respiratory failure and allograft physiology in the lung transplant recipient. This scoping review was conducted to systematically map the research describing ventilation and relevant physiological parameters post-bilateral lung transplantation with the aim to identify any associations with patient outcomes and gaps in the current knowledge base.

METHODS

To identify relevant publications, comprehensive literature searches of electronic bibliographic databases were conducted with the guidance of an experienced librarian in MEDLINE, EMBASE, SCOPUS and the Cochrane Library. The search strategies were peer-reviewed using the PRESS (Peer Review of Electronic Search Strategies) checklist. The reference lists of all relevant review articles were surveyed. Publications were included in the review if they described relevant ventilation parameters in the immediate post-operative period, published between 2000 and 2022 and involved human subjects undergoing bilateral lung transplantation. Publications were excluded if they included animal models, only single-lung transplant recipients or only patients managed with extracorporeal membrane oxygenation.

RESULTS

A total of 1212 articles were screened, 27 were subject to full-text review and 11 were included in the analysis. The quality of the included studies was assessed to be poor with no prospective multi-centre randomised controlled trials. The frequency of reported retrospective LPV parameters was as follows: tidal volume (82%), tidal volume indexed to both donor and recipient body weight (27%) and plateau pressure (18%). Data suggest that undersized grafts are at risk of unrecognised higher tidal volume ventilation indexed to donor body weight. The most reported patient-centred outcome was graft dysfunction severity in the first 72 h.

CONCLUSION

This review has identified a significant knowledge gap that indicates uncertainty regarding the safest ventilation practice in lung transplant recipients. The risk may be greatest in patients with established high-grade primary graft dysfunction and undersized allografts, and these factors may define a sub-group that warrants further investigation.

Capnodynamic monitoring of lung volume and blood flow in response to increased positive end-expiratory pressure in moderate to severe COVID-19 pneumonia: an observational study

Background

The optimal level of positive end-expiratory pressure (PEEP) during mechanical ventilation for COVID-19 pneumonia remains debated and should ideally be guided by responses in both lung volume and perfusion. Capnodynamic monitoring allows both end-expiratory lung volume (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{EELV}}_{{{\text{CO}}_{2} }}$$\end{document}EELVCO2) and effective pulmonary blood flow (EPBF) to be determined at the bedside with ongoing ventilation.

Methods

Patients with COVID-19-related moderate to severe respiratory failure underwent capnodynamic monitoring of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{EELV}}_{{{\text{CO}}_{2} }}$$\end{document}EELVCO2 and EPBF during a step increase in PEEP by 50% above the baseline (PEEP_low to PEEP_high). The primary outcome was a > 20 mm Hg increase in arterial oxygen tension to inspired fraction of oxygen (P/F) ratio to define responders versus non-responders. Secondary outcomes included changes in physiological dead space and correlations with independently determined recruited lung volume and the recruitment-to-inflation ratio at an instantaneous, single breath decrease in PEEP. Mixed factor ANOVA for group mean differences and correlations by Pearson’s correlation coefficient are reported including their 95% confidence intervals.

Results

Of 27 patients studied, 15 responders increased the P/F ratio by 55 [24–86] mm Hg compared to 12 non-responders (p < 0.01) as PEEP_low (11 ± 2.7 cm H₂O) was increased to PEEP_high (18 ± 3.0 cm H₂O). The \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{EELV}}_{{{\text{CO}}_{2} }}$$\end{document}EELVCO2 was 461 [82–839] ml less in responders at PEEP_low (p = 0.02) but not statistically different between groups at PEEP_high. Responders increased both \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{EELV}}_{{{\text{CO}}_{2} }}$$\end{document}EELVCO2 and EPBF at PEEP_high (r = 0.56 [0.18–0.83], p = 0.03). In contrast, non-responders demonstrated a negative correlation (r = − 0.65 [− 0.12 to − 0.89], p = 0.02) with increased lung volume associated with decreased pulmonary perfusion. Decreased (− 0.06 [− 0.02 to − 0.09] %, p < 0.01) dead space was observed in responders. The change in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{EELV}}_{{{\text{CO}}_{2} }}$$\end{document}EELVCO2 correlated with both the recruited lung volume (r = 0.85 [0.69–0.93], p < 0.01) and the recruitment-to-inflation ratio (r = 0.87 [0.74–0.94], p < 0.01).

Conclusions

In mechanically ventilated patients with moderate to severe COVID-19 respiratory failure, improved oxygenation in response to increased PEEP was associated with increased end-expiratory lung volume and pulmonary perfusion. The change in end-expiratory lung volume was positively correlated with the lung volume recruited and the recruitment-to-inflation ratio. This study demonstrates the feasibility of capnodynamic monitoring to assess physiological responses to PEEP at the bedside to facilitate an individualised setting of PEEP.

Trial registration: NCT05082168 (18th October 2021).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04110-0.

Interactions in the 2×2×2 factorial randomised clinical STEPCARE trial and the potential effects on conclusions: a protocol for a simulation study

Background

Randomised clinical trials with a factorial design may assess the effects of multiple interventions in the same population. Factorial trials are carried out under the assumption that the trial interventions have no interactions on outcomes. Here, we present a protocol for a simulation study investigating the consequences of different levels of interactions between the trial interventions on outcomes for the future 2×2×2 factorial designed randomised clinical Sedation, TEmperature, and Pressure after Cardiac Arrest and REsuscitation (STEPCARE) trial in comatose patients after out-of-hospital cardiac arrest.

Methods

By simulating a multisite trial with 50 sites and 3278 participants, and a presumed six-month all-cause mortality of 60% in the control population, we will investigate the validity of the trial results with different levels of interaction effects on the outcome. The primary simulation outcome of the study is the risks of type-1 and type-2 errors in the simulated scenarios, i.e. at what level of interaction is the desired alpha and beta level exceeded. When keeping the overall risk of type-1 errors ≤ 5% and the risk of type-2 errors ≤ 10%, we will quantify the maximum interaction effect we can accept if the planned sample size is increased by 5% to take into account possible interaction between the trial interventions. Secondly, we will assess how interaction effects influence the minimal detectable difference we may confirm or reject to take into account 5% (small interaction effect), 10% (moderate), or 15% (large) positive interactions in simulations with no ‘true’ intervention effect (type-1 errors) and small (5%), moderate (10%), or large negative interactions (15%) in simulations with ‘true’ intervention effects (type-2 errors). Moreover, we will investigate how much the sample size must be increased to account for a small, moderate, or large interaction effects.

Discussion

This protocol for a simulation study will inform the design of a 2×2×2 factorial randomised clinical trial of how potential interactions between the assessed interventions might affect conclusions. Protocolising this simulation study is important to ensure valid and unbiased results.

Trial registration

Not relevant

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06796-7.

Level of sedation in critically ill adult patients: a protocol for a systematic review with meta-analysis and trial sequential analysis

INTRODUCTION

It is standard of care to provide sedation to critically ill patients to reduce anxiety, discomfort and promote tolerance of mechanical ventilation. Given that sedatives can have differing effects based on a variety of patient and pharmacological characteristics, treatment approaches are largely based on targeting the level of sedation. The benefits of differing levels of sedation must be balanced against potential adverse effects including haemodynamic instability, causing delirium, delaying awakening and prolonging the time of mechanical ventilation and intensive care stay. This systematic review with meta-analysis aims to investigate the current evidence and compare the effects of differing sedation levels in adult critically ill patients.

METHODS AND ANALYSES

We will conduct a systematic review based on searches of preidentified major medical databases (eg, MEDLINE, EMBASE, CENTRAL) and clinical trial registries from their inception onwards to identify trials meeting inclusion criteria. We will include randomised clinical trials comparing any degree of sedation with no sedation and lighter sedation with deeper sedation for critically ill patients admitted to the intensive care unit. We will include aggregate data meta-analyses and trial sequential analyses. Risk of bias will be assessed with domains based on the Cochrane risk of bias tool. An eight-step procedure will be used to assess if the thresholds for clinical significance are crossed, and the certainty of the evidence will be assessed using Grades of Recommendations, Assessment, Development and Evaluation.

ETHICS AND DISSEMINATION

No formal approval or review of ethics is required as individual patient data will not be included. This systematic review has the potential to highlight (1) whether one should believe sedation to be beneficial, harmful or neither in critically ill adults; (2) the existing knowledge gaps and (3) whether the recommendations from guidelines and daily clinical practice are supported by current evidence. These results will be disseminated through publication in a peer-reviewed journal.

Characteristics, clinical findings and outcomes of acute aortic dissection: A comparison between an Australian emergency department and the International Registry of Acute Aortic Dissection

OBJECTIVES

Acute aortic dissection (AAD) is a rare, life-threatening condition for which the International Registry of Acute Aortic Dissection (IRAD) remains the most detailed clinical resource. The present study compared the characteristics, clinical findings and outcomes of patients presenting to Liverpool Hospital, NSW, Australia (LPOOL) with AAD to those in IRAD. Secondary aims were to identify LPOOL patient variables associated with 30-day mortality and to assess the impact of transfer times in the ED on 30-day mortality.

METHODS

Retrospective observational study of patients presenting to LPOOL with AAD between 2011 and 2019. Clinical records were examined and compared with IRAD data. Variables in LPOOL associated (P < 0.10) with 30-day mortality by univariable analysis were subsequently entered in a multivariable logistic regression to identify independent predictors. Mediation analysis was performed to assess the impact of ED transfer times on 30-day mortality.

RESULTS

The characteristics, clinical findings and outcomes of 156 LPOOL patients were overall similar to those in IRAD. Syncope, weakness or paralysis, raised lactate and chest X-ray abnormalities were identified as independent predictors of 30-day mortality. Time from ED to ICU explained 28% of the variance in survival at 30 days.

CONCLUSIONS

The characteristics, clinical features and outcomes of patients with AAD presenting to LPOOL appeared similar to those reported by IRAD. The identification of independent mortality predictors serves to improve the understanding of local AAD presentations. Reducing ED to ICU transfer times may increase 30-day survival and further interdisciplinary research should be considered.

Target temperature management following cardiac arrest: a systematic review and Bayesian meta-analysis

Background

Temperature control with target temperature management (TTM) after cardiac arrest has been endorsed by expert societies and adopted in international clinical practice guidelines but recent evidence challenges the use of hypothermic TTM.

Methods

Systematic review and Bayesian meta-analysis of clinical trials on adult survivors from cardiac arrest undergoing TTM for at least 12 h comparing TTM versus no TTM or with a separation > 2 °C between intervention and control groups using the PubMed/MEDLINE, EMBASE, CENTRAL databases from inception to 1 September 2021 (PROSPERO CRD42021248140). All randomised and quasi-randomised controlled trials were considered. The risk ratio and 95% confidence interval for death (primary outcome) and unfavourable neurological recovery (secondary outcome) were captured using the original study definitions censored up to 180 days after cardiac arrest. Bias was assessed using the updated Cochrane risk-of-bias for randomised trials tool and certainty of evidence assessed using the Grading of Recommendation Assessment, Development and Evaluation methodology. A hierarchical robust Bayesian model-averaged meta-analysis was performed using both minimally informative and data-driven priors and reported by mean risk ratio (RR) and its 95% credible interval (95% CrI).

Results

In seven studies (three low bias, three intermediate bias, one high bias, very low to low certainty) recruiting 3792 patients the RR by TTM 32–34 °C was 0.95 [95% CrI 0.78—1.09] for death and RR 0.93 [95% CrI 0.84—1.02] for unfavourable neurological outcome. The posterior probability for no benefit (RR ≥ 1) by TTM 32–34 °C was 24% for death and 12% for unfavourable neurological outcome. The posterior probabilities for favourable treatment effects of TTM 32–34 °C were the highest for an absolute risk reduction of 2–4% for death (28–53% chance) and unfavourable neurological outcome (63–78% chance). Excluding four studies without active avoidance of fever in the control arm reduced the probability to achieve an absolute risk reduction > 2% for death or unfavourable neurological outcome to ≤ 50%.

Conclusions

The posterior probability distributions did not support the use of TTM at 32–34 °C compared to 36 °C also including active control of fever to reduce the risk of death and unfavourable neurological outcome at 90–180 days. Any likely benefit of hypothermic TTM is smaller than targeted in RCTs to date.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-03935-z.

Management of acute atrial fibrillation in the intensive care unit: An international survey

BACKGROUND

Atrial fibrillation (AF) is common in intensive care unit (ICU) patients and is associated with poor outcomes. Different management strategies exist, but the evidence is limited and derived from non-ICU patients. This international survey of ICU doctors evaluated the preferred management of acute AF in ICU patients.

METHOD

We conducted an international online survey of ICU doctors with 27 questions about the preferred management of acute AF in the ICU, including antiarrhythmic therapy in hemodynamically stable and unstable patients and use of anticoagulant therapy.

RESULTS

A total of 910 respondents from 70 ICUs in 14 countries participated in the survey with 24%-100% of doctors from sites responding. Most ICUs (80%) did not have a local guideline for the management of acute AF. The preferred first-line strategy for the management of hemodynamically stable patients with acute AF was observation (95% of respondents), rhythm control (3%), or rate control (2%). For hemodynamically unstable patients, the preferred strategy was observation (48%), rhythm control (48%), or rate control (4%). Overall, preferred antiarrhythmic interventions included amiodarone, direct current cardioversion, beta-blockers other than sotalol, and magnesium in that order. A total of 67% preferred using anticoagulant therapy in ICU patients with AF, among whom 61% preferred therapeutic dose anticoagulants and 39% prophylactic dose anticoagulants.

CONCLUSION

This international survey indicated considerable practice variation among ICU doctors in the clinical management of acute AF, including the overall management strategies and the use of antiarrhythmic interventions and anticoagulants.

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background

Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies.

Methods

In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality.

Findings

Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference –1·69 [–9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5–8] vs 6 [5–8] cm H₂O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52–23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75–0·86]; p<0·0001).

Interpretation

Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status.

Funding

No funding.

Fentanyl versus placebo with ketamine and rocuronium for patients undergoing rapid sequence intubation in the emergency department: The FAKT study-A randomized clinical trial

Objective

The objective was to determine whether the use of fentanyl with ketamine for emergency department (ED) rapid sequence intubation (RSI) results in fewer patients with systolic blood pressure (SBP) measurements outside the pre‐specified target range of 100–150 mm Hg following the induction of anesthesia.

Methods

This study was conducted in the ED of five Australian hospitals. A total of 290 participants were randomized to receive either fentanyl or 0.9% saline (placebo) in combination with ketamine and rocuronium, according to a weight‐based dosing schedule. The primary outcome was the proportion of patients in each group with at least one SBP measurement outside the prespecified range of 100–150 mm Hg (with adjustment for baseline abnormality). Secondary outcomes included first‐pass intubation success, hypotension, hypertension and hypoxia, mortality, and ventilator‐free days 30 days following enrollment.

Results

A total of 142 in the fentanyl group and 148 in the placebo group commenced the protocol. A total of 66% of patients receiving fentanyl and 65% of patients receiving placebo met the primary outcome (difference = 1%, 95% CI = −10 to 12). Hypotension (SBP ≤ 99 mm Hg) was more common with fentanyl (29% vs. 16%; difference = 13%, 95% CI = 3% to 23%), while hypertension (≥150 mm Hg) occurred more with placebo (69% vs. 55%; difference = 14%, 95% CI = 3 to 24). First‐pass success rate, 30 day mortality, and ventilator‐free days were similar.

Conclusions and Relevance

There was no difference in the primary outcome between groups, although lower blood pressures were more common with fentanyl. Clinicians should consider baseline hemodynamics and postinduction targets when deciding whether to use fentanyl as a coinduction agent with ketamine.

In reply: Association between mean systemic filling pressure and acute kidney injury

We thank Prof. Xue and colleagues for their interest [letter ref] in our observational study on associations between mean systemic filling pressure and acute kidney injury (AKI) following elective cardiac surgery [2]. To be precise, we have not argued that calculating the mean systemic filling pressure analogue (P_msa ) provides a surrogate for renal venous pressure. We have proposed that P_msa represents a closer physiological approximation of the renal venous pressure compared to central venous pressure (CVP). This is by virtue of representing the distending pressure within the entire intravascular compartment, particularly influenced by changes in splanchnic vascular compliance, and the 'upstream' anatomical proximity of the renal vessels on the P_msa -CVP pressure gradient for venous return in the inferior vena cava.

Association of deranged cerebrovascular reactivity with brain injury following cardiac arrest: a post-hoc analysis of the COMACARE trial

BACKGROUND

Impaired cerebrovascular reactivity (CVR) is one feature of post cardiac arrest encephalopathy. We studied the incidence and features of CVR by near infrared spectroscopy (NIRS) and associations with outcome and biomarkers of brain injury.

METHODS

A post-hoc analysis of 120 comatose OHCA patients continuously monitored with NIRS and randomised to low- or high-normal oxygen, carbon dioxide and mean arterial blood pressure (MAP) targets for 48 h. The tissue oximetry index (TO_x) generated by the moving correlation coefficient between cerebral tissue oxygenation measured by NIRS and MAP was used as a dynamic index of CVR with TO_x > 0 indicating impaired reactivity and TO_x > 0.3 used to delineate the lower and upper MAP bounds for disrupted CVR. TO_x was analysed in the 0-12, 12-24, 24-48 h time-periods and integrated over 0-48 h. The primary outcome was the association between TO_x and six-month functional outcome dichotomised by the cerebral performance category (CPC1-2 good vs. 3-5 poor). Secondary outcomes included associations with MAP bounds for CVR and biomarkers of brain injury.

RESULTS

In 108 patients with sufficient data to calculate TO_x, 76 patients (70%) had impaired CVR and among these, chronic hypertension was more common (58% vs. 31%, p = 0.002). Integrated TO_x for 0-48 h was higher in patients with poor outcome than in patients with good outcome (0.89 95% CI [- 1.17 to 2.94] vs. - 2.71 95% CI [- 4.16 to - 1.26], p = 0.05). Patients with poor outcomes had a decreased upper MAP bound of CVR over time (p = 0.001), including the high-normal oxygen (p = 0.002), carbon dioxide (p = 0.012) and MAP (p = 0.001) groups. The MAP range of maintained CVR was narrower in all time intervals and intervention groups (p < 0.05). NfL concentrations were higher in patients with impaired CVR compared to those with intact CVR (43 IQR [15-650] vs 20 IQR [13-199] pg/ml, p = 0.042).

CONCLUSION

Impaired CVR over 48 h was more common in patients with chronic hypertension and associated with poor outcome. Decreased upper MAP bound and a narrower MAP range for maintained CVR were associated with poor outcome and more severe brain injury assessed with NfL. Trial registration ClinicalTrials.gov, NCT02698917 .

New-onset atrial fibrillation in the intensive care unit: Protocol for an international inception cohort study (AFIB-ICU)

INTRODUCTION

New-onset atrial fibrillation (NOAF) is frequently observed in critically ill patients and may be associated with prolonged hospital stay and increased mortality. Considerable variation exists in the reported frequencies of NOAF due to the lack of a standardised definition and detection method. Importantly, there are limited data on NOAF in the intensive care unit (ICU). Thus, we aim to provide contemporary epidemiological data on NOAF in the ICU.

METHODS AND ANALYSIS

We have designed an international inception cohort study including at least 1,000 consecutive adult patients acutely admitted to the ICU without prior history of persistent or permanent AF. We will present data on the incidence, risk factors, used management strategies and outcomes of NOAF. We will register data daily during stay in the ICU for a maximum of 90 days after admission. The incidence of NOAF and management strategies used will be presented descriptively, and we will use Cox regression analyses including competing risk analyses to assess risk factors for NOAF and any association with 90-day mortality.

CONCLUSION

The outlined international AFIB-ICU inception cohort study will provide contemporary data on the incidence, risk factors, used management strategies and outcomes of NOAF in adult ICU patients.

ETHICS AND DISSEMINATION

This observational study poses no risk to the included patients. All participating sites will obtain relevant approvals according to national laws before patient enrollment. Funding sources will have no influence on data handling, analyses or writing of the manuscript. The study report(s) will be submitted to an international peer-reviewed journal.

Associations between mean systemic filling pressure and acute kidney injury: An observational cohort study following cardiac surgery

BACKGROUND

Venous congestion has been implied in cardiac surgery-associated acute kidney injury (CSA-AKI). The mean systemic filling pressure may provide a physiologically more accurate estimate of renal venous pressure and renal perfusion pressure but its association with CSA-AKI has not been reported.

METHODS

Patients admitted to ICU following cardiac surgery without pre-operative renal dysfunction were included with monitoring of mean arterial pressure (MAP) and central venous pressure (CVP) and cardiac output (CO) to calculate the mean systemic filling pressure analogue (P_msa ). The AKI-KDIGO guidelines were used to define CSA-AKI. Logistic regression models including CO, heart rate, MAP, CVP and P_msa were used to ascertain the association with CSA-AKI and reported by odds ratio (OR) with 95% confidence interval (95%CI) and area under the curve (AUROC).

RESULTS

One hundred and thirty patients (out of 221 screened) were included of whom 66 (51%) developed CSA-AKI. Patients with CSA-AKI were older, with greater weight and increased stay in ICU while the proportion of comorbidities, type of surgical procedures, APACHE III scores and fluid volumes administered were similar to patients without AKI. The P_msa , but not CVP, was associated with CSA-AKI (OR 1.2 95%CI [1.16-1.25]). Renal perfusion pressure was associated with CSA-AKI estimated as MAP-P_msa (OR 0.81 [0.76-0.86]) and MAP-CVP (OR 0.89 [0.85-0.93]) with the former generating a higher AUROC (median difference 0.10 [0.07-0.12], P < .001) in the regression model.

CONCLUSIONS

The P_msa in post-operative cardiac surgery patients was associated with the development of CSA-AKI also when incorporated into estimates of renal perfusion pressure.

Volume status and volume responsiveness in postoperative cardiac surgical patients: An observational, multicentre cohort study

BACKGROUND

The best strategy to identify patients in whom fluid loading increases cardiac output (CO) following cardiac surgery remains debated. This study examined the utility of a calculated mean systemic filling pressure analogue (P_msa ) and derived variables to explain the response to a fluid bolus.

METHODS

The P_msa was calculated using retrospective, observational cohort data in the early postoperative period between admission to the intensive care unit and extubation within 6 hours. The venous return pressure gradient (VRdP) was calculated as P_msa  - central venous pressure. Concurrent changes induced by a fluid bolus in the ratio of the VRdP over P_msa , the volume efficiency (E_vol ), were studied to assess fluid responsiveness. Changes between P_msa and derived variables and CO were analysed by Wilcoxon rank-sum test, hierarchial clustering and multiple linear regression.

RESULTS

Data were analysed for 235 patients who received 489 fluid boluses. The P_msa increased with consecutive fluid boluses (median difference [range] 1.3 [0.5-2.4] mm Hg, P = .03) with a corresponding increase in VRdP (median difference 0.4 [0.2-0.6] mm Hg, P = .04). Hierarchical cluster analysis only identified E_vol and the change in CO within one cluster. The multiple linear regression between P_msa and its derived variables and the change in CO (overall r²  = .48, P < .001) demonstrated the best partial regression between the continuous change in CO and the concurrent E_vol (r = .55, P < .001).

CONCLUSION

The mean systemic filling P_msa enabled a comprehensive interpretation of fluid responsiveness with volume efficiency useful to explain the change in CO as a continuous phenomenon.

Interpreting the results of clinical trials, embracing uncertainty: A Bayesian approach

Most clinical trials use null hypothesis significance testing with frequentist statistical inference to report P values and confidence intervals for effect estimates. This method leads to a dichotomisation of results as 'significant' or 'non-significant'. A more nuanced interpretation may often be considered and in particular when the majority of the confidence interval for the effect estimate suggests benefit or harm. In contrast to the frequentist dichotomised approach based on a P value, the application of Bayesian statistics allocates credibility to a continuous spectrum of possibilities and for this reason a Bayesian approach to inference is often warranted as it will incorporate uncertainty when updating our current belief with information from a new trial. The use of Bayesian statistics is introduced in this paper for a hypothetical sepsis trial with worked examples in the R language for Statistical Computing environment and the open-source statistical software JASP. It is hoped that this general introduction to Bayesian inference stimulates some interest and confidence among clinicians to consider applying these methods to the interpretation of new evidence for interventions relevant to anaesthesia and intensive care medicine.

Post-operative renal failure management in mechanical circulatory support patients

Acute kidney injury (AKI) occurs commonly in patients requiring mechanical circulatory support (MCS) after cardiothoracic surgery. The prognostic implications of AKI in this patient group relate closely to the pathophysiology and risk factors associated with the underlying disease; pre-operative, intra-operative, and post-operative variables; hemodynamic factors; and type of support device used. General approaches to AKI management, including prevention strategies, medical management, and hemodynamic support, are also applicable in patients requiring MCS. Approaches to renal replacement therapy vary depend on patient factors, device-specific factors, and local preferences and experience. In this invited narrative review, we discuss the pathophysiology, risk factors, and prognostic implications of AKI in post-operative adult patients following institution of MCS. Management strategies for AKI are presented with a focus on those supported with either extracorporeal membrane oxygenation or a ventricular assist device.

Tissue oxygenation indices of cerebrovascular autoregulation in healthy volunteers: a comparison of two NIRS devices

BACKGROUND

Correlation coefficients between blood pressure and cerebral oxygen saturation measured using near-infrared spectrometry may be used to derive the tissue oximetry index of cerebral autoregulation. Cerebral oxygen saturations demonstrate poor agreement between near-infrared spectrometers however it is unclear if measurements of autoregulation are similarly specific to the equipment used.

METHODS

Cerebral oxygen saturation was monitored bilaterally in 74 healthy volunteers using both the FORE-SIGHT and EQUANOX monitors in random order. The tissue oximetry index was calculated during changes in blood pressure induced by isometric handgrip manoeuvres and the mean bias and limits of agreement were calculated.

RESULTS

Tissue oximetry index measured by FORE-SIGHT was higher than EQUANOX (0.21 ± 0.16 versus 0.15 ± 0.17, P < 0.001) and limits of agreement were -0.24 to 0.36. Baseline cerebral oxygen saturation by FORE-SIGHT was lower than EQUANOX by 1.48% (CI95% 0.63-2.33) and limits of agreement ranged from -11.8% to 8.8%.

CONCLUSIONS

The substantial bias and wide limits of agreement for the tissue oximetry index as a measure of cerebral autoregulation indicate that values must be treated as specific to models of near-infrared spectrometers.

Airway management during in-hospital cardiac arrest: An international, multicentre, retrospective, observational cohort study

AIM

To determine the type of airway devices used during in-hospital cardiac arrest (IHCA) resuscitation attempts.

METHODS

International multicentre retrospective observational study of in-patients aged over 18 years who received chest compressions for cardiac arrest from April 2016 to September 2018. Patients were identified from resuscitation registries and rapid response system databases. Data were collected through review of resuscitation records and hospital notes. Airway devices used during cardiac arrest were recorded as basic (adjuncts or bag-mask), or advanced, including supraglottic airway devices, tracheal tubes or tracheostomies. Descriptive statistics and multivariable regression modelling were used for data analysis.

RESULTS

The final analysis included 598 patients. No airway management occurred in 36 (6%), basic airway device use occurred at any time in 562 (94%), basic airway device use without an advanced airway device in 182 (30%), tracheal intubation in 301 (50%), supraglottic airway in 102 (17%), and tracheostomy in 1 (0.2%). There was significant variation in airway device use between centres. The intubation rate ranged between 21% and 90% while supraglottic airway use varied between 1% and 45%. The choice of tracheal intubation vs. supraglottic airway as the second advanced airway device was not associated with immediate survival from the resuscitation attempt (odds ratio 0.81; 95% confidence interval 0.35-1.8).

CONCLUSION

There is wide variation in airway device use during resuscitation after IHCA. Only half of patients are intubated before return of spontaneous circulation and many are managed without an advanced airway. Further investigation is needed to determine optimal airway device management strategies during resuscitation following IHCA.

Evaluating the influence of data collector training for predictive risk of death models: an observational study

BACKGROUND

Severity-of-illness scoring systems are widely used for quality assurance and research. Although validated by trained data collectors, there is little data on the accuracy of real-world data collection practices.

OBJECTIVE

To evaluate the influence of formal data collection training on the accuracy of scoring system data in intensive care units (ICUs).

STUDY DESIGN AND METHODS

Quality assurance audit conducted using survey methodology principles. Between June and December 2018, an electronic document with details of three fictitious ICU patients was emailed to staff from 19 Australian ICUs who voluntarily submitted data on a web-based data entry form. Their entries were used to generate severity-of-illness scores and risks of death (RoDs) for four scoring systems. The primary outcome was the variation of severity-of-illness scores and RoDs from a reference standard.

RESULTS

50/83 staff (60.3%) submitted data. Using Bayesian multilevel analysis, severity-of-illness scores and RoDs were found to be significantly higher for untrained staff. The mean (95% high-density interval) overestimation in RoD due to training effect for patients 1, 2 and 3, respectively, were 0.24 (0.16, 0.31), 0.19 (0.09, 0.29) and 0.24 (0.1, 0.38) respectively (Bayesian factor >300, decisive evidence). Both groups (trained and untrained) had wide coefficients of variation up to 38.1%, indicating wide variability. Untrained staff made more errors in interpreting scoring system definitions.

INTERPRETATION

In a fictitious patient dataset, data collection staff without formal training significantly overestimated the severity-of-illness scores and RoDs compared with trained staff. Both groups exhibited wide variability. Strategies to improve practice may include providing adequate training for all data collection staff, refresher training for previously trained staff and auditing the raw data submitted by individual ICUs. The results of this simulated study need revalidation on real patients.

Comparison of echocardiographic and invasive measures of volaemia and cardiac performance in critically ill patients

Echocardiographic measurements are used in critical care to evaluate volume status and cardiac performance. Mean systemic filling pressure and global heart efficiency measures intravascular volume and global heart function. This prospective study conducted in fifty haemodynamically stabilized, mechanically ventilated patients investigated relationships between static echocardiographic variables and estimates of global heart efficiency and mean systemic filling pressure. Results of univariate analysis demonstrated weak correlations between left ventricular end-diastolic volume index (r = 0.27, p = 0.04), right atrial volume index (rho = 0.31, p = 0.03) and analogue mean systemic filling pressure; moderate correlations between left ventricular ejection fraction (r = 0.31, p = 0.03), left ventricular global longitudinal strain (r = 0.36, p = 0.04), tricuspid annular plane systolic excursion (rho = 0.37, p = 0.01) and global heart efficiency. No significant correlations were demonstrated by multiple regression. Mean systemic filling pressure calculated with cardiac output measured by echocardiography demonstrated good agreement and correlation with invasive techniques (bias 0.52 ± 1.7 mmHg, limits of agreement -2.9 to 3.9 mmHg, r = 0.9, p < 0.001). Static echocardiographic variables did not reliably reflect the volume state as defined by estimates of mean systemic filling pressure. The agreement between static echocardiographic variables of cardiac performance and global heart efficiency lacked robustness. Echocardiographic measurements of cardiac output can be reliably used in calculation of mean systemic filling pressure.

In-hospital cardiac arrest in hospitals with mature rapid response systems - a multicentre, retrospective cohort study

AIM

To investigate in-hospital cardiac arrests (IHCAs) according to the Ustein template in hospitals with mature systems utilizing rapid response teams (RRTs), with a special reference to preceding RRT factors and factors associated with a favourable neurological outcome (cerebral performance category (CPC) 1-2) at hospital discharge.

METHODS

Multicentre, retrospective cohort study between 2017-2018 including two Finnish and one Australian university affiliated tertiary hospitals.

RESULTS

A total 309 IHCAs occurred with an incidence of 0.78 arrests per 1000 hospital admissions. The median age of the patients was 72 years, 63% were male and 73% had previously lived a fully independent life with a median Charlson comorbidity index of two. Before the IHCA, 16% of the patients had been reviewed by RRTs and 26% of the patients fulfilled RRT activation criteria in the preceding 8 h of the IHCA. Return of spontaneous circulation was achieved in 53% of the patients and 28% were discharged from hospital with CPC 1-2. In a multivariable model, younger age, no pre-arrest RRT criteria, arrest in normal work hours, witnessed arrest and shockable initial rhythm were independently associated with CPC 1-2 at hospital discharge.

CONCLUSIONS

In hospitals with mature rapid response systems most IHCA patients live a fully independent life with low burden of comorbid diseases before their hospital admission, the IHCA incidence is low and outcome better than traditionally believed. Deterioration before IHCA is present in a significant number of patients and improved monitoring and earlier interventions may further improve outcomes.

Prospective, observational study of carbon dioxide gaps and free energy change and their association with fluid therapy following cardiac surgery

Background Venoarterial carbon dioxide pressure (p_v-a CO₂ ) and content (C_v-a CO₂ ) differences, including the ratio to arteriovenous oxygen content difference (C_a-v O₂ ), and free energy changes (-∆∆G_a-v ) may reflect tissue hypoperfusion. The associations with changes in cardiac output (CO) or oxygen consumption (VO₂ ) following fluid bolus administration were investigated. Methods Single-centre, observational study of 89 adult post-operative cardiac surgical patients admitted to ICU. The p_v-a CO₂ , C_v-a CO₂ and their ratios to C_a-v O₂ as well as the -∆∆G_a-v were determined before and after a 250-500 mL fluid bolus using arterial, central venous and mixed venous blood gas analyses. Responses associated with changes ≥ or <15% in CO or oxygen consumption (VO₂ ) were compared. Results In 234 boluses, the mixed venous to arterial p_v-a CO₂ and its ratio to C_a-v O₂ were independently associated with an increase in CO; odds ratio 1.3 (95% CI 1.1-1.5) and 1.7 (95% CI 1.5-1.9) respectively, P < .001) and VO₂ ; odds ratio 2.1 (95% CI 1.3-3.1), P < .001 for C_a-v O₂ . No measures of p_v-a CO₂ , C_v-a CO₂ or related ratios to the C_a-v O₂ were associated with an increase in CO ≥15% following a single volume bolus. The mixed venous and central venous C_v-a CO₂ to C_a-v O₂ ratios were different for the first bolus episode only; mean differences 0.81 (95% CI 0.13-1.5), P = .02 and 0.44 (95% CI 0.06-0.82), P = .02, respectively, for increased VO₂  ≥ 15%. The -∆∆G_a-v did not change. Conclusion The venoarterial carbon dioxide gradients and related calculations to assess the adequacy of tissue perfusion before a fluid bolus were not associated with subsequent increases in CO of oxygen consumption. Editorial Comment In some shock conditions, regional tissue hypoperfusion can be obvious and arterio-venous differences for CO₂ or O₂ may reflect this. This is not always the case; sometimes there are A-V differences or even a high lactate level without any obvious regional tissue hypoperfusion. Fluid therapy is a cornerstone in shock resuscitation treatment, but determining optimal fluid therapy is challenging, particularly as fluid overload may be detrimental. Fluid challenges are used as an "ex juvantebus" method to dose fluid therapy, but it is not clear if a positive response reflects a state of hypoperfusion or the existence of a cardiac reserve. Still, a better understanding on how to target and guide fluid therapy is welcome, and studies digging into the problem are needed. Here, invasively monitored post-operative cardiac surgery patients are assessed as a model to investigate if carbon dioxide gaps and free energy charge may be useful in detecting possible tissue hypoperfusion.

Storage time of red blood cells among ICU patients with septic shock

BACKGROUND

We aimed to describe the exposure to blood transfusions and mortality among patients with septic shock.

METHODS

We did a retrospective cohort study of two cohorts-patients with septic shock registered in a Danish ICU database (2008-2010) and patients from the Transfusion Requirements in Septic Shock (TRISS) trial (2011-2013). We extracted information on blood transfusions issued to all patients. We investigated the number of patients receiving very fresh blood (less than 7 days), very old blood (more than 24 days) and blood with a mixture of storage time.

RESULTS

In the Danish cohort, 1637 patients were included of whom 1394 (85%) received 20,239 blood units from 14 days prior the ICU admission to 90 days after; 33% were transfused before, 77% in the ICU and 36% after ICU. The exposure to exclusively very fresh or very old blood was 3% and 4%, respectively. In the TRISS cohort, 77% of the 937 patients received 5047 RBC units; 3% received exclusively very fresh and 13% very old blood. The point estimate of mortality was higher among patients receiving large amounts of exclusively very fresh and very old blood, but the number of patients were very small.

CONCLUSIONS

Patients with septic shock were transfused both before and after ICU. Exposure to blood of less than 7 days or more than 24 days old were limited. We were not able to detect higher mortality among the limited number of patients with septic shock transfused with very fresh or very old blood.

Cerebrovascular autoregulation following cardiac arrest: Protocol for a post hoc analysis of the randomised COMACARE pilot trial

BACKGROUND

Approximately two-thirds of the mortality following out of hospital cardiac arrest is related to devastating neurological injury. Previous small cohort studies have reported an impaired cerebrovascular autoregulation following cardiac arrest, but no studies have assessed the impact of differences in oxygen and carbon dioxide tensions in addition to mean arterial pressure management.

METHODS

This is a protocol and statistical analysis plan to assess the correlation between changes in cerebral tissue oxygenation and arterial pressure as measure of cerebrovascular autoregulation, the tissue oxygenation index, in patients following out of hospital cardiac arrest and in healthy volunteers. The COMACARE study included 120 comatose survivors of out of hospital cardiac arrest admitted to ICU and managed with low-normal or high-normal targets for mean arterial pressure, arterial oxygen and carbon dioxide partial pressures. In addition, 102 healthy volunteers have been investigated as a reference group for the tissue oxygenation index. In both cohorts, the cerebral tissue oxygenation was measured by near infrared spectroscopy.

CONCLUSIONS

Cerebrovascular autoregulation is critical to maintain homoeostatic brain perfusion. This study of changes in autoregulation following out of hospital cardiac arrest over the first 48 hours, as compared to data from healthy volunteers, will generate important physiological information that may guide the rationale and design of interventional studies.

The effect of systemic corticosteroids on the incidence of gastrointestinal bleeding in critically ill adults: a systematic review with meta-analysis

PURPOSE

To assess the effect of systemic corticosteroids on the incidence of gastrointestinal bleeding in adult critically ill patients.

METHODS

We systematically reviewed randomised clinical trials comparing systemic corticosteroids administered for more than 24 h with placebo/no treatment in adult critically ill patients. Trial selection, data abstraction and risk of bias assessments were performed in duplicate. We used trial sequential analysis (TSA) to assess the risk of random errors and the grading of recommendations, assessment, development, and evaluations (GRADE) approach to assess the quality of evidence. The primary outcome was the incidence of clinically important gastrointestinal bleeding within 90 days. The secondary outcome was the incidence of gastrointestinal bleeding of any severity within 90 days.

RESULTS

Twenty-five trials (n = 14,615) reported data for the primary outcome and 55 trials (n = 21,792) for the secondary outcome. The pooled incidence of clinically important gastrointestinal bleeding was 2.3% in the corticosteroid group and 1.8% in the control group (RR, 1.26; 95% CI, 1.01-1.57; I² = 0%, TSA-adjusted CI 0.51-3.14). We observed no difference in the risk of gastrointestinal bleeding of any severity (RR, 1.10; 95% CI, 0.92-1.32; I² = 0%, TSA-adjusted CI 0.87-1.38). The GRADE quality of evidence was low (risk of bias and imprecision).

CONCLUSIONS

We observed an overall low incidence of clinically important gastrointestinal bleeding among adult critically ill patients. Corticosteroids may slightly increase the incidence of clinically important gastrointestinal bleeding, but not bleeding of any severity. Rarity of events, infrequent trial reporting and high risk of bias reduced the quality of evidence.

Assessment of volume status and volume responsiveness in the ICU: Protocol for an observational, multicentre cohort study

BACKGROUND

Expansion of the intravascular compartment is common to treat haemodynamic instability in ICU patients. The most useful and accurate variables to guide and evaluate a fluid challenge remain debated and incompletely investigated resulting in significant variability in practice. The analogue mean systemic pressure has been reported as a measure of the intravascular volume state.

METHODS

This is a protocol and statistical analysis plan for a review of the application of an analogue of the mean systemic pressure and the use of derived variables to assess the volume state and volume responsiveness. A pulmonary artery catheter was used in 286 postoperative cardiac surgical patients to monitor cardiac output before and after a fluid bolus in addition to arterial and central venous pressures. With otherwise similar monitoring, echocardiography was used in 540 general ICU patients to determine cardiac outputs and indices related to intravascular filling. The responses to a fluid bolus or the passive leg raising manoeuvre will be investigated using continuous and dichotomous definitions of volume responsiveness. The results will be stratified according to the method of monitoring cardiac output.

CONCLUSIONS

This study investigating 2 cohorts that encompass a wide variety of reasons for haemodynamic instability will illustrate the applicability of the analogue mean systemic pressure and derived variables to assess the volume state and responsiveness. The results may guide the rationale and design of interventional studies.

The stop-flow arm equilibrium pressure in preoperative patients: Stressed volume and correlations with echocardiography

BACKGROUND

The distending intravascular pressure at no flow conditions reflects the stressed volume. While this haemodynamic variable is recognised as clinically important, there is a paucity of reports of its range and responsiveness to volume expansion in patients without cardiovascular disease and no reports of correlations to echocardiographic assessments of left ventricular filling.

METHODS

Twenty-seven awake (13 male), spontaneously breathing patients without any history of cardiopulmonary, vascular or renal disease were studied prior to induction of anaesthesia. The no-flow equilibrium pressure in the arm following rapid circulatory occlusion (P_arm ) was measured via a radial arterial catheter. Transthoracic echocardiography was used to measure left ventricular end diastolic area and volume as well as the diameter of the inferior vena cava. The P_arm and echocardiographic variables were measured before and after administration of 500 mL 0.9% NaCl over 10 minutes. Changes were analysed by paired t test, Pearson's correlation and multiple linear regression.

RESULTS

P_arm increased overall from 22 ± 5 mm Hg to 25 ± 6 mm Hg (mean difference 3.0 ± 4.5 mm Hg, P = 0.002) following the fluid bolus with corresponding increases in arterial pressure and echocardiographic variables. Variability in the direction of the P_arm response reflected concomitant changes in vascular compliance. Only weak correlations were observed between changes in P_arm and inferior vena cava diameter indexed to body surface area (R²  = 0.29, P = 0.01).

CONCLUSION

Preoperative measurements of P_arm increased following acute expansion of the intravascular volume. Echocardiography demonstrated poor correlation with P_arm .

Does the addition of fentanyl to ketamine improve haemodynamics, intubating conditions or mortality in emergency department intubation: A systematic review

BACKGROUND

Ketamine is an induction agent frequently used for general anaesthesia in emergency medicine. Generally regarded as haemodynamically stable, it can cause hypertension and tachycardia and may cause or worsen shock. The effects of ketamine may be improved by the addition of fentanyl to the induction regime. We conducted a systematic review to identify evidence with regard to the effect of adding fentanyl to an induction regime of ketamine and a paralysing agent on post-induction haemodynamics, intubating conditions and mortality.

METHODS

We conducted a search of the Cochrane library, EMBASE, MEDLINE, PROQUEST, OpenGrey and clinical trial registries. Prominent authors were contacted in order to identify additional literature pertinent to the research question. Studies were included if they pertained to intubation of adult patients in the prehospital or emergency department environments and included an induction regime of ketamine and a paralysing agent, with at least one outcome measure of haemodynamics, intubating conditions or mortality. Search results were reviewed by two investigators independently, adjudicated by a third investigator where disagreement occurred.

RESULTS

One observational study was identified that partially answered the research question.

DISCUSSION

Only one observational study was identified that partially answered the research question. This paper demonstrated that the use of fentanyl as a pretreatment increases the incidence of post-induction hypotension, a phenomenon that was seen with propofol, midazolam and ketamine. The difference in hypotension between these agents was not statistically significant. The impact of this on patient-orientated outcomes is unclear.

FentAnyl or placebo with KeTamine for emergency department rapid sequence intubation: The FAKT study protocol

BACKGROUND

Some critically ill patients require rapid sequence intubation in the emergency department, and ketamine is one sedative agent employed, due to its relative haemodynamic stability. Tachycardia and hypertension are frequent side effects, and in less stable patients, shock can be unmasked or exacerbated. The use of fentanyl as a co-induction agent may lead to a smoother haemodynamic profile post-induction, which may lead to reduced mortality in this critically ill cohort. This randomised controlled trial aims to compare the effect of administering fentanyl vs placebo in a standardised induction regimen with ketamine and rocuronium on (a) the percentage of patients in each group with a systolic blood pressure outside the range of 100-150 mm Hg within 10 minutes of induction, (b) the laryngoscopic view, and (c) 30-day mortality.

METHODS/DESIGN

Three hundred patients requiring rapid sequence intubation in participating emergency departments will be randomised to receive either fentanyl or placebo (0.9% saline) in addition to ketamine and rocuronium according to a standardised, weight-based induction regimen. The primary outcome measure is the percentage of patients in each group with a systolic blood pressure outside the range of 100-150 mm Hg within 10 minutes of induction. Secondary outcome measures include the laryngoscopic view, percentage of first pass success, 30-day mortality and number of ventilator-free days at 30 days.

DISCUSSION

The effect of adding fentanyl to an induction regimen of ketamine and rocuronium will be evaluated, both in terms of post-intubation physiology, the effect on intubating conditions, and 30-day mortality.

Is cerebrovascular autoregulation associated with outcomes after major noncardiac surgery? A prospective observational pilot study

BACKGROUND

Studies have identified multiple risk factors for development of cognitive decline after surgery. Impaired cerebrovascular autoregulation may be a contributor to postoperative cognitive decline.

METHODS

One hundred and forty patients admitted for major elective noncardiac surgery were recruited. Near-infrared spectroscopy was used to calculate the tissue oxygenation index of dynamic autoregulation (TOx). The primary endpoint was Day 3 cognitive recovery as assessed using the Postoperative Quality of Recovery Scale. The secondary endpoint was a combined major adverse event of death, acute myocardial infarction, cardiac arrest, stroke, pulmonary embolism, sepsis, and acute kidney injury at Day 30.

RESULTS

Higher optimal TOx values, signifying impaired autoregulation, were associated with worse outcomes. Patients who cognitively recovered at Day 3 (n = 47) had lower optimal TOx values (TOx_opt ) than patients who did not recover (n = 22): 0.06 (0.24) vs 0.18 (0.16) (mean [SD]), P = 0.02. Patients who did not suffer a major adverse event (n = 102) had lower TOx_opt than patients who did (n = 17): 0.09 (0.21) vs 0.20 (0.27), P = 0.04. When dichotomized as having impaired or intact autoregulation based on TOx_opt levels, a value of TOx_opt ≥0.1 correctly identified 72.7% of patients who did not cognitively recover, OR 3.3 (1.1-9.9) (Odds ratio, [95% CI]), P = 0.03. TOx_opt ≥0.1 correctly identified 82.4% of patients who suffered a major adverse event, OR 4.7 (1.3-17.2), P = 0.02.

CONCLUSIONS

In older and higher risk patients having major noncardiac surgery, impaired cerebrovascular autoregulation was associated with failure of cognitive recovery in the early postoperative period and with 1-month mortality and morbidity.

Evidence for the effectiveness of chlorhexidine bathing and health care-associated infections among adult intensive care patients: a trial sequential meta-analysis

Background

Health care associated infections (HAI) among adults admitted to the intensive care unit (ICU) have been shown to increase length of stay, the cost of care, and in some cases increased the risk of hospital death (Kaye et al., J Am Geriatr Soc 62:306-11, 2014; Roberts et al., Med Care 48:1026-35, 2010; Warren et al., Crit Care Med 34:2084-9, 2006; Zimlichman et al., JAMA Intern Med 173:2039-46, 2013). Daily bathing with chlorhexidine gluconate (CHG) has been shown to decrease the risk of infection in the ICU (Loveday et al., J Hosp Infect 86:S1-S70, 2014). However, due to varying quality of published studies, and varying estimates of effectiveness, CHG bathing is not universally practiced. As a result, current opinion of the merit of CHG bathing to reduce hospital acquired infections in the ICU, is divergent, suggesting a state of ‘clinical equipoise’.

This trial sequential meta-analysis aims to explore the current status of evidence for the effectiveness of chlorhexidine (CHG) bathing, in adult intensive care patients, to reduce hospital acquired infections, and address the question: do we need more trials?

Methods

A systematic literature search was undertaken to identify trials assessing the effectiveness of chlorhexidine bathing to reduce risk of infection, among adult intensive care patients. With particular focus on: (1) Blood stream infections (BSI); (2) Central Line Associated Blood Stream Infections (CLABSI); (3) Multi-Resistant Drug Organism (MRDO); (4) Ventilator Associated Pneumonia; and, Catheter Associated Urinary Tract Infections (CAUTI). Only randomised-control or cluster randomised cross-over trials, were include in our analysis. A Trial Sequential Analysis (TSA) was used to describe the current status of evidence for the effectiveness of chlorhexidine (CHG) bathing, in adult intensive care patients, to reduce hospital acquired infections.

Results

Five trials were included in our final analysis - two trials were individual patient randomised-controlled, and the remaining cluster-randomised-crossover trials. Daily bathing with CHG was estimated to reduce BSI in the ICU by approximately 29% (Der-Simonian and Laird, Random-Effects.

(DL-RE) Incidence Rate Ratio (IRR) = 0.71, 95% confidence interval (CI) 0.51, 0.98); reduce CLABSI in the ICU by approximately 40% (DL-RE IRR = 0.60, 95% CI 0.34, 1.04); reduce MDRO in the ICU by approximately 18% (DL-RE IRR = 0.82, 95% CI 0.69, 0.98); no effect in reducing VAP in the ICU (DL-RE IRR = 1.33, 95% CI 0.81, 2.18); and, no effect in reducing CAUTI in the ICU (DL-RE IRR = 0.77, 95% CI 0.52, 1.15). Upper (superiority) monitoring boundaries from TSA were not crossed for all five specific infections in the ICU.

Conclusion

Routine bathing with CHG does not occur in the ICU setting, and TSA suggests that more trials are needed to address the current state of ‘clinical equipoise’. Ideally these studies would be conducted among a diverse group of ICU patients, and to the highest standard to ensure generalisability of results.

Communication with Families Regarding Organ and Tissue Donation after Death in Intensive Care (COMFORT): a multicentre before-and-after study

OBJECTIVE

To implement a best-practice intervention offering deceased organ donation, testing whether it increased family consent rates.

DESIGN

A multicentre before-and-after study of a prospective cohort compared with pre-intervention controls.

SETTING

Nine Australian intensive care units.

PARTICIPANTS

Families and health care professionals caring for donor-eligible patients without registered donation preferences or aged ≤ 16 years.

INTERVENTION

A multicomponent intervention including offers of deceased organ donation from specially trained designated requesters using a structured conversation separate to end-of-life discussions.

MAIN OUTCOME MEASURE

Proportion of families consenting to organ donation.

RESULTS

Consent was obtained in 87/164 cases (53%) during the intervention period compared with 14/25 cases (56%) pre-intervention (P = 0.83). The odds ratio (OR) of obtaining consent during the intervention period relative to preintervention was 1.13 (95% CI, 0.48-2.63; P = 0.78). During the intervention period, designated requesters obtained consent in 55/98 cases (56%), compared with 32/66 cases (48%) in which the medical team managing patient care raised donation (P = 0.34). Factors independently associated with increased consent were: family-raised organ donation (OR, 4.34; 95% CI, 1.79-10.52; P = 0.001), presence of an independent designated requester (OR, 3.84; 95% CI, 1.35- 10.98; P = 0.012), and multiple donation conversations per case (OR, 3.35; 95% CI, 1.93-5.81; P < 0.001). Consent decreased when patients were of non-Christian religion (OR, 0.18; 95% CI, 0.04-0.91; P = 0.038) and end-of-life and donation meetings were separate (OR, 0.38; 95% CI, 0.16-0.89; P = 0.026).

CONCLUSION

Implementation of a multicomponent intervention did not increase consent rates for organ donation, although some components of the intervention exerted significant effect.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12613000815763. ClinicalTrials.gov: NCT01922310.

Daily intra-abdominal pressure, Sequential Organ Failure Score and fluid balance predict duration of mechanical ventilation

BACKGROUND

Elevated intra-abdominal pressure (IAP) is a common occurrence in mechanically ventilated patients in the intensive care unit (ICU). This study was undertaken to determine the relationship between IAP, pulmonary compliance and the duration of mechanical ventilation.

METHODS

A prospective study of 220 consecutively enrolled mechanically ventilated patients admitted to a mixed surgical-medical ICU in a tertiary referral hospital. The IAP was measured at least twice daily, benchmarked against consensus guidelines. Dynamic pulmonary compliance was calculated together with admission Acute Physiology and Chronic Health Evaluation (APACHE III) score and daily Sequential Organ Failure Assessment (SOFA) score.

RESULTS

No relationship between highest IAP for the day and pulmonary compliance (P = 0.61) was found. For each 5 mm Hg increase in IAP, the risk of remaining intubated increased 19% (HR = 1.19, 95% CI: 0.98-1.44); for each standard deviation increase in SOFA score (3.7 points), the risk of remaining intubated increased by 14% (HR = 1.14, 95% CI: 0.98-1.33); and for each 1 L increase in fluid balance, the risk of remaining intubated increased by 11% (HR = 1.11, 95% CI: 1.04-1.19). A nomogram was developed to predict the probability of extubation based on daily highest IAP for the day, SOFA score and fluid balance.

CONCLUSION

IAPs did not correlate with pulmonary compliance in critically ill patients. Increased IAP was associated with a longer duration of mechanical ventilation. A nomogram integrating daily IAP, SOFA score and fluid balance may be used to predict the duration of mechanical ventilation.