A Multicenter, Open-Label, Randomized Controlled Trial of a Conservative Fluid Management Strategy Compared With Usual Care in Participants After Cardiac Surgery: The Fluids After Bypass Study.

OBJECTIVES: There is little evidence to guide fluid administration to patients admitted to the ICU following cardiac surgery. This study aimed to determine if a protocolized strategy known to reduce fluid administration when compared with usual care reduced ICU length of stay following cardiac surgery. DESIGN: Prospective, multicenter, parallel-group, randomized clinical trial. SETTING: Five cardiac surgical centers in New Zealand conducted from November 2016 to December 2018 with final follow-up completed in July 2019. PATIENTS: Seven-hundred fifteen patients undergoing cardiac surgery; 358 intervention and 357 usual care. INTERVENTIONS: Randomization to protocol-guided strategy utilizing stroke volume variation to guide administration of bolus fluid or usual care fluid administration until desedation or up to 24 hours. Primary outcome was length of stay in ICU. Organ dysfunction, mortality, process of care measures, patient-reported quality of life, and disability-free survival were collected up to day 180. MEASUREMENTS AND MAIN RESULTS: Overall 666 of 715 (93.1%) received at least one fluid bolus. Patients in the intervention group received less bolus fluid (median [interquartile range], 1,000 mL [250-2,000 mL] vs 1,500 mL [500-2,500 mL]; p < 0.0001) and had a lower overall fluid balance (median [interquartile range], 319 mL [-284 to 1,274 mL] vs 673 mL [38-1,641 mL]; p < 0.0001) in the intervention period. There was no difference in ICU length of stay between the two groups (27.9 hr [21.8-53.5 hr] vs 25.6 hr [21.9-64.6 hr]; p = 0.95). There were no differences seen in development of organ dysfunction, quality of life, or disability-free survival at any time points. Hospital mortality was higher in the intervention group (4% vs 1.4%; p = 0.04). CONCLUSIONS: A protocol-guided strategy utilizing stroke volume variation to guide administration of bolus fluid when compared with usual care until desedation or up to 24 hours reduced the amount of fluid administered but did not reduce the length of stay in ICU.

Prominent eustachian valve: An uncommon cause of a common problem during extracorporeal membrane oxygenation support.

Suck down events in an extracorporeal membrane oxygenation (ECMO) circuit, due to vein wall being suctioned onto the cannula inflow ports, lead to low circuit flows. These low flow states can be reversed with fluid administration. We present a patient with a prominent eustachian valve (EV) which was encountered while managing the patient on ECMO post lung transplantation for pleuroparenchymal fibroelastosis. We hypothesize that presence of a prominent EV can induce suck down events and needs to be recognized in the differential diagnosis of this problem. This case adds to the literature to increase the awareness of this rare but significant problem.

Nonocclusive mesenteric infarction after cardiac surgery: potential biomarkers.

BACKGROUND: Nonocclusive mesenteric ischemia can cause intestinal infarction but the diagnosis is challenging. This prospective study evaluated three plasma biomarkers of intestinal infarction after cardiac surgery. MATERIALS AND METHODS: Patients were recruited after cardiac surgery if they required laparotomy (with or without intestinal resection) for suspected nonocclusive mesenteric ischemia. Plasma levels of D-lactate, intestinal fatty acid-binding protein (i-FABP), and smooth muscle actin (SMA) before laparotomy were measured. RESULTS: Twenty patients were recruited (68 ± 9 y, EuroSCORE: 8.7 ± 2.8, mortality 70%). A positive laparotomy (n = 13) was associated with no change in D-lactate (P = 0.95), decreased i-FABP (P = 0.007), and increased SMA (P = 0.01). All patients with high SMA had a positive laparotomy. A subgroup analysis was undertaken in the eight patients who required multiple laparotomies. D-lactate increased between the two laparotomies in nonsurvivors (n = 4). Plasma i-FABP (P = 0.008) and SMA (P = 0.036) significantly decreased after the bowel resection, regardless of survival outcome. CONCLUSIONS: None of the biomarkers were accurate enough to reliably diagnose intestinal infarction. However, all patients with high values of SMA developed intestinal infarction, thus warranting further investigation. An increasing D-lactate after intestinal resection suggests impending death.

Floor covering and surface identification for assistive mobile robotic real-time room localization application.

Assistive robotic applications require systems capable of interaction in the human world, a workspace which is highly dynamic and not always predictable. Mobile assistive devices face the additional and complex problem of when and if intervention should occur; therefore before any trajectory assistance is given, the robotic device must know where it is in real-time, without unnecessary disruption or delay to the user requirements. In this paper, we demonstrate a novel robust method for determining room identification from floor features in a real-time computational frame for autonomous and assistive robotics in the human environment. We utilize two inexpensive sensors: an optical mouse sensor for straightforward and rapid, texture or pattern sampling, and a four color photodiode light sensor for fast color determination. We show how data relating floor texture and color obtained from typical dynamic human environments, using these two sensors, compares favorably with data obtained from a standard webcam. We show that suitable data can be extracted from these two sensors at a rate 16 times faster than a standard webcam, and that these data are in a form which can be rapidly processed using readily available classification techniques, suitable for real-time system application. We achieved a 95% correct classification accuracy identifying 133 rooms' flooring from 35 classes, suitable for fast coarse global room localization application, boundary crossing detection, and additionally some degree of surface type identification.

Stakeholder views addressing the development and uptake of powered wheelchair assistive technology.

PURPOSE: The objective of this research is to identify stakeholder views with regard to the development of effective powered wheelchair assistive technologies more suited to the user and carer needs, whilst also meeting the requirements for other stakeholders, such that developers can be better guided towards producing solutions which have a better chance of getting to the market place and hence to the end user. METHOD: A questionnaire was designed to collect the views of all stakeholders and circulated to a statistically representative number of them. The question rating data were then checked for correlation between groups, and within groups, to establish validity. RESULTS: The 74 stakeholders across the eight classes who responded had a good correlation between each other, with a cross class "Pearson's correlation" ranging between 0.7 and 0.95, and the "Fleiss's Kappa reliability of agreement" within each class ranging between 0.07 and 0.36. CONCLUSIONS: This research has identified that all stakeholders should be involved in the development of the technology and that some may benefit in 'role-reversal' to help understand user problems and stakeholder concerns more clearly. Cost was a significant barrier to the uptake of appropriate technology, and training of users and carers was a major issue. Furthermore, development should not increase user isolation and the impact on the user must be monitored for 'quality of life'. Technical support and training should be given to the user and their carers, and equipment must be adaptive to meet the changing needs of the user. Implications for Rehabilitation Improved acceptance and use of technology by the user and their carers. Reduced rejection of appropriate provision. Improved mobility and interaction with others. Improved quality of life for users and carers.

Design and statistical analysis plan for a trial comparing a conservative fluid management strategy with usual care in patients after cardiac surgery: the FAB study.

BACKGROUND: Cardiac surgery is one of the most frequently performed major surgical procedures. Following surgery, haemodynamic instability and prevention of organ dysfunction may be treated in the intensive care unit (ICU) with intravenous fluid, inotropes and vasopressors. In other surgical groups, liberal intravenous fluid administration and a positive fluid balance have been associated with adverse outcomes and increased risk of morbidity and mortality. There is a paucity of evidence to guide intravenous fluid administration in cardiac surgery patients. We have previously shown that a protocol-guided strategy avoiding unnecessary fluid administration significantly reduces fluid loading. OBJECTIVE: To present the design and statistical analysis plan for a randomised controlled trial comparing a conservative fluid management strategy to usual care in patients after cardiac surgery. METHODS: We designed a prospective, multicentre, parallel-group, randomised controlled trial - the FAB (Fluids After Bypass) study. A total of 700 patients undergoing cardiac surgery using cardiopulmonary bypass who have a European System for Cardiac Operative Risk Evaluation (EuroSCORE) II ≥ 0.9 will be enrolled in this study and randomly allocated to a protocol-guided strategy using stroke volume variation to guide administration of bolus fluid or to usual care fluid administration in a 1:1 ratio, stratified by centre. Study treatment will be administered from post-operative admission to the ICU until de-sedation or for a 24-hour period (whichever is shorter). The primary outcome is ICU length of stay. Secondary endpoints include quality of life and disability-free survival at 3 and 6 months after surgery, and process-of-care, physiological and safety measures. CONCLUSION: This trial aims to determine whether a protocol-guided strategy that avoids unnecessary fluid administration reduces ICU length of stay and improves outcomes in higher-risk adults undergoing cardiac surgery.

Is the New Zealand Early Warning Score useful following cardiac surgery?

AIMS: The rate of medical emergency team (MET) calling among post-cardiac surgery patients is unknown. We set out to determine what the call frequency would be if MET activation occurred in every instance that the early warning score (EWS) breached our local threshold, what the outcome was for these patients and what the calling rate might be if the proposed New Zealand EWS (NZEWS) system was implemented with 100% adherence. METHODS: The clinical records of 400 consecutive post-cardiac surgery patients were examined. The number of times a patient's EWS reached the threshold which mandated a call to the MET was determined, as was the actual rate of calling, the occurrence of inpatient death and re-admission to the intensive care unit (ICU). The rate of calling was then determined using the NZEWS, and with a routine modification to the heart rate score. RESULTS: There were 73 occasions (MET events) where the EWS reached the MET calling threshold. The MET was only called twice. There were no inpatient deaths and 12 ICU re-admissions in the study cohort. Nine ICU re-admissions were preceded by a MET event, two by cardiac arrest and one had neither. Re-scoring with NZEWS yielded 53 events. Eight of the 12 ICU admissions were preceded by a NZEWS event. CONCLUSIONS: The rate of MET triggering EWS in patients post-cardiac surgery is high at 182/1,000 admissions. Using NZEWS could reduce the MET calling rate without significant risk to patient safety.

Feature determination from powered wheelchair user joystick input characteristics for adapting driving assistance.

Background: Many powered wheelchair users find their medical condition and their ability to drive the wheelchair will change over time. In order to maintain their independent mobility, the powered chair will require adjustment over time to suit the user's needs, thus regular input from healthcare professionals is required. These limited resources can result in the user having to wait weeks for appointments, resulting in the user losing independent mobility, consequently affecting their quality of life and that of their family and carers. In order to provide an adaptive assistive driving system, a range of features need to be identified which are suitable for initial system setup and can automatically provide data for re-calibration over the long term. Methods: A questionnaire was designed to collect information from powered wheelchair users with regard to their symptoms and how they changed over time. Another group of volunteer participants were asked to drive a test platform and complete a course which represented manoeuvring in a very confined space as quickly as possible. Two of those participants were also monitored over a longer period in their normal home daily environment. Features, thought to be suitable, were examined using pattern recognition classifiers to determine their suitability for identifying the changing user input over time. Results: The results are not designed to provide absolute insight into the individual user behaviour, as no ground truth of their ability has been determined, they do nevertheless demonstrate the utility of the measured features to provide evidence of the users' changing ability over time whilst driving a powered wheelchair. Conclusions: Determining the driving features and adjustable elements provides the initial step towards developing an adaptable assistive technology for the user when the ground truths of the individual and their machine have been learned by a smart pattern recognition system.

Finding the red flags: Swallowing difficulties after cardiac surgery in patients with prolonged intubation.

PURPOSE: This retrospective audit set out to identify referral rates, swallowing characteristics, and risk factors for dysphagia and silent aspiration in at-risk patients after cardiac surgery. Dysphagia and silent aspiration are associated with poorer outcomes post cardiac surgery. METHODS: One hundred ninety patients who survived cardiac surgery and received more than 48 hours of intubation were included. Preoperative, perioperative, and postoperative information was collected. RESULTS: Forty-one patients (22%) were referred to speech-language pathology for a swallowing assessment. Twenty-four of these patients (13%) underwent instrumental swallowing assessment, and silent aspiration was observed in 17 (70% of patients diagnosed as having dysphagia via instrumental assessment). Multilogistic analysis revealed previous stroke (P < .05), postoperative stroke (P < .001), and tracheostomy (P < .001) independently associated with dysphagia. The odds ratio for being diagnosed as having pneumonia, if a patient was diagnosed as having dysphagia, was 3.3. CONCLUSIONS: Patients identified with dysphagia after cardiac surgery had a high incidence of silent aspiration and increased risk of pneumonia. However, referral rates were low in this at-risk patient group. Early identification and ongoing assessment and appropriate management of dysphagic patients by a speech-language pathologist are strongly recommended.

Bedside placement of an endobronchial valve to aid invasive ventilation and weaning from extracorporeal membrane oxygenation.

A bronchopleural fistula (BPF) is a life-threatening complication of cardiothoracic surgery and acute illness. There is no consensus on how best to treat a BPF. Recently, endobronchial one-way valves, designed for bronchoscopic lung volume reduction in emphysema, have been used to treat BPFs. We describe the use of an endobronchial oneway valve, placed at the bedside via flexible bronchoscopy, to treat a BPF in a patient with hypoxic respiratory failure, supported by extracorporeal membrane oxygenation (ECMO), secondary to pneumonia. We believe that this is the first published description of this technique being used in a patient needing ECMO support.

The accuracy of multidetector computed tomography in the diagnosis of non-occlusive mesenteric ischaemia in patients after cardiovascular surgery.

OBJECTIVE: To determine the accuracy of multidetector computed tomography (MDCT) in the diagnosis of nonocclusive mesenteric ischaemia (NOMI) among patients after cardiovascular surgery. DESIGN, SETTING AND PARTICIPANTS: A retrospective review of 38 patients in a cardiothoracic intensive care unit who underwent MDCT examination before laparotomy for suspected NOMI between January 2001 and December 2012. INTERVENTION AND MAIN OUTCOME MEASURES: The MDCT studies were examined independently by three radiologists, who were asked to make a determination on the presence or absence of NOMI. The radiological diagnosis was compared against the surgical and/or histological outcome to determine the diagnostic accuracy of MDCT. RESULTS: The sensitivity and specificity of MDCT in the diagnosis of NOMI were 96% and 33%-60%, respectively. The positive and negative likelihood ratios and diagnostic odds ratio were 1.43-2.39, 0.072-0.13 and 11-33.2, respectively. The inter-rater agreement was 68%, with a Fleiss κ of 0.43. CONCLUSIONS: MDCT has high sensitivity but lacks specificity in the diagnosis of NOMI. Its main value is in selection of patients for non-operative management, at least in the short-to-medium term.

Resuscitation for major trauma.

Disability from traumatic injury is on the increase worldwide. Dogma rather than scientific evidence has tended to be responsible for determining the treatment of major trauma victims. Evidence is now beginning to emerge, however, questioning the dogma, and suggesting that different treatment options may yield better outcomes. This review examines the recent literature in resuscitation for major trauma.