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Cardiopulmonary exercise testing (CPET) objectively informs preoperative risk stratification prior to major surgery. CPET facilities are resource intensive and therefore more cost-effective triage methods are desirable for scalability. We tested two dynamic CPET parameters (end-tidal CO2 (PetCO2) and heart rate (HR)) to early phase exercise and resting diffusion capacity (DLCO) as potential point of care assessments that could be used outside of formal CPET testing facilities.We conducted a retrospective cohort study including 84 patients who underwent CPET prior to elective major abdominal cancer surgery. Data were analysed for PetCO2 and HR in response to early phase (2 minutes) exercise as well as resting DLCO against postoperative complications and two-year survival. Complications were classified according to Clavien-Dindo score into less severe and severe (CDIIIb) grades. Optimal cut points for predicting outcomes were determined using the Youden index of receiver operating characteristic (ROC) curves. Multivariate regression modeling including both logistic and Cox proportional-hazards model adjusted to age and comorbidity burden to analyse the association between the selected parameters and postoperative outcomes.PetCO2, in response to two minutes of loaded exercise was higher in survivors than in non-survivors (median (IQR) 40.0 (4.2) mmHg vs. 34.5 (5.2) mmHg, p0.001). There was no association between chronotropic response and postoperative outcome. The optimal cut point for predicting postoperative complications and survival was 38 mmHg and 37.1 mmHg for PetCO2, respectively. Low PetCO2 was associated with considerably lower odds of survival (OR 0.12; 95% CI 0.03, 0.47; p=0.003) and additionally increased odds of severe postoperative complications (OR 6.77; 95% CI 1.45, 38.4; p=0.019). Reduced age-predicted DLCO%80% was associated with increased mortality (HR 5.27; 95% CI 1.09, 25.5; p=0.039).Assessment of DLCO at rest and dynamic assessment of PetCO2 during the early phase of exercise may potentially be developed as inexpensive point of care triage tools to scale objective preoperative risk assessment.

Background Preoperative risk stratification is used to derive an optimal treatment plan for patients requiring cancer surgery. Patients with reversible risk factors are candidates for prehabilitation programmes. This pilot study explores the impact of preoperative covariates of comorbid disease (Charlson Co-morbidity Index), preoperative serum biomarkers, and traditional cardiopulmonary exercise testing (CPET)-derived parameters of functional capacity on postoperative outcomes after major colorectal cancer surgery. Methods Consecutive patients who underwent CPET prior to colorectal cancer surgery over a 2-year period were identified and a minimum of 2-year postoperative follow-up was performed. Postoperative assessment included: Clavien-Dindo complication score, Comprehensive Complication Index, Days at Home within 90 days (DAH-90) after surgery, and overall survival. Results The Charlson Co-morbidity Index did not discriminate postoperative complications, or overall survival. In contrast, low preoperative haemoglobin, low albumin, or high neutrophil count were associated with postoperative complications and reduced overall survival. CPET-derived parameters predictive of postoperative complications, DAH-90, and reduced overall survival included measures of VCO2 kinetics at anaerobic threshold (AT), peakVO2 (corrected to body surface area), and VO2 kinetics during the post-exercise recovery phase. Inflammatory parameters and CO2 kinetics added significant predictive value to peakVO2 within bi-variable models for postoperative complications and overall survival (P < 0.0001). Conclusion Consideration of modifiable ‘triple low’ preoperative risk (anaemia, malnutrition, deconditioning) factors and inflammation will improve surgical risk prediction and guide prehabilitation. Gas exchange parameters that focus on VCO2 kinetics at AT and correcting peakVO2 to body surface area (rather than absolute weight) may improve CPET-derived preoperative risk assessment.

Ventriculo-meningitis (VM) is an important complication of external ventricular drains (EVDs) in neurosurgical patients. Consequences include increased morbidity, mortality, and duration of hospital stay. Early diagnosis of EVD-associated VM allows earlier treatment intervention. The cell index (CI) may provide a simple measure that overcomes the limitations of isolated cerebrospinal fluid (CSF) parameters and other diagnostic tests, allowing earlier prediction of VM.All patients admitted to a tertiary hospital and requiring EVD insertion during 2015 and 2016 were assessed for inclusion in this retrospective case-control study. Patients with a known or suspected intracranial infection were excluded. Of the 186 patients who underwent EVD insertion, 95 patients were included in the final cohort. Data pertaining to patient characteristics and laboratory indices were extracted from health records and the microbiology laboratory database. The CI was calculated as the ratio of temporally related CSF leukocytes/erythrocytes to peripheral blood leukocytes/erythrocytes. Data from patients with microbiologically confirmed VM were analyzed in comparison with those not developing VM during the course of their stay. Categorical and continuous variables with skewed distributions were analyzed by Chi square and Mann-Whitney tests, respectively.EVD-associated VM developed in 7.4% of patients. The highest CSF CI (within 3 days prior to diagnosis of VM or at any time for those not developing VM) differed significantly between the two groups (16; IQR 10.8-48.5 vs. 3.3; IQR 1.0-12.8, respectively; p = .046). The area under the receiver operating characteristic curve (AUROC) for the highest CI was 0.727 (95% confidence interval [CI] 0.526-0.929; p = .027). A CI of 10.4 provided a sensitivity and specificity of 80.5% and 70.5%, respectively, for the early diagnosis of VM.In neurosurgical patients with an EVD, the CSF CI significantly predicted the development of VM.

The Duke Activity Status Index (DASI), a patient-administered questionnaire, is used to quantify functional capacity in patients undergoing cancer surgery. This retrospective cohort study assessed whether the DASI was accurate in predicting peak oxygen consumption (pVO2) that was objectively measured using cardiopulmonary exercise testing (CPET) in 43 consecutive patients scheduled for elective major cancer surgery at a tertiary cancer centre. The primary outcome measured the limits of agreement between DASI-predicted pVO2 and actual measured pVO2. The study population was elderly (median 63 years, interquartile range 18), 58% were male, with the majority having intraabdominal cancer surgery. Although the DASI scores were statistically related to the measured pVO2 (N = 43, adjusted R2 = 0.20, p = 0.002), both the bias (8 ml kg− 1 min− 1) and 95% limits of agreement (19.5 to − 3.4 ml kg− 1 min− 1) between the predicted and measured pVO2 were large. Using some of the individual components, recalibrating the intercept and regression coefficient of the total DASI score did not substantially improve its ability to predict the measured pVO2. In summary, both the limits of agreement and bias between the measured and DASI-predicted pVO2 were substantial. The DASI-predicted pVO2 based on patient’s assessment of their functional status could not be considered a reliable surrogate of measured pVO2 during CPET for the population of patients pending major cancer surgery and cannot, therefore, be used as a triage tool for referral to CPET centres for objective risk assessment.

Background Anaesthetists use dexamethasone principally for its anti-emetic effect. The purpose of this study was to characterize the effects of a single intraoperative dose of dexamethasone on cellular and metabolic components of the immune system in patients undergoing laparoscopic surgical procedures. Methods In this prospective double-blind trial, female patients undergoing elective major laparoscopic surgery were randomized to receive saline (Control group, n=16) or dexamethasone 4 mg (Dexamethasone group, n=16) i.v. after the induction of anaesthesia. Inflammatory markers and immune cell counts were examined at 24 and 48 h and 6 weeks after surgery. The changes from baseline preoperative values were compared between groups using a Mann–Whitney U-test, and linear mixed models were used to validate the findings. Results No differences in concentrations of serum glucose and interleukin-6 were observed between groups after surgery. The increase in C-reactive protein concentration at 24 h after surgery was greater in the control group [median (interquartile range), 33 (25–65) vs 17 (7–26) mg dl−1; P=0.018]. Extensive changes in the counts of white cells, including most lymphocyte subsets, were observed 24 h after surgery, and dexamethasone appeared to attenuate most of these changes. Changes at 48 h and 6 weeks did not differ between groups. Conclusions In female patients undergoing elective laparoscopic gynaecological surgery, dexamethasone administration appears to attenuate inflammation and to alter immune cell counts at 24 h, with no effects identified after this time. The importance of these changes for postoperative immune function is unknown. Trial registration Australia and New Zealand Clinical Trials Registry (ACTRN12608000340336).

SUMMARY Aim It is uncertain whether hypocalcaemia is associated with an increased risk of bleeding. This study assessed the dose-related relationship between ionised calcium concentrations and in vitro clot strength measured by maximum amplitude (MA) on the thromboelastograph (TEG). Methods A total of 610 patients who were at risk of bleeding or had active bleeding between 2010 and 2014 were considered in this retrospective cohort study. A scatter plot with Pearson correlation coefficient (r) and multiple linear regression was used to assess the dose-related relationship between ionised calcium concentrations and MA on the TEG. Results The mean ionised calcium of the patients was 1·10 mmol L−1 (interquartile range: 1·04–1·17) and 235 (38·5%) of them had hypocalcaemia (1 mmol L−1, during critical bleeding is recommended.

Haemodynamic monitoring is a vital part of daily practice in anaesthesia and intensive care. Although there is evidence to suggest that goal-directed therapy may improve outcomes in the perioperative period, which haemodynamic targets we should aim at to optimise patient outcomes remain elusive and controversial. This review highlights the pitfalls in commonly used haemodynamic targets, including arterial blood pressure, central venous pressure, cardiac output, central venous oxygen saturation and dynamic haemodynamic indices. Evidence suggests that autoregulation in regional organ circulation may change either due to chronic hypertension or different disease processes such as traumatic brain injury, cerebrovascular ischaemia or haemorrhage; this will influence the preferred blood pressure target. Central venous pressure can be influenced by multiple pathophysiological factors and, unless central venous pressure is very low, it is rarely useful as a predictor for fluid responsiveness. Central venous oxygen saturation can be easily increased by a high arterial oxygen tension, making it useless as a surrogate marker of good cardiac output or systemic oxygen delivery in the presence of hyperoxaemia. Many dynamic haemodynamic indices have been reported to predict fluid responsiveness, but they all have their own limitations. There is also insufficient evidence to support that giving fluid until the patient is no longer fluid responsive can improve patient-centred outcomes. With the exception in the context of preventing contrast-induced nephropathy, large randomised controlled studies suggest that excessive fluid treatment may prolong duration of mechanical ventilation without preventing acute kidney injury in the critically ill.

The 'weekend' effect is a controversial theory that links reduced staffing levels, staffing seniority and supportive services at hospitals during 'out-of-office hours' time periods with worsening patient outcomes. It is uncertain whether admitting elective surgery patients to intensive care units (ICU) during 'out-of-office hours' time periods mitigates this affect through higher staffing ratios and seniority.Over a 3-year period in Western Australia's largest private hospital, this retrospective nested-cohort study compared all elective surgical patients admitted to the ICU based on whether their admission occurred 'in-office hours' (Monday-Friday 08.00-18.00 hours) or 'out-of-office hours' (all other times). The main outcomes were surgical complications using the Dindo-Clavien classification and length-of-stay data.Of the total 4363 ICU admissions, 3584 ICU admissions were planned following elective surgery resulting in 2515 (70.2%) in-office hours and 1069 (29.8%) out-of-office hours elective ICU surgical admissions. Out-of-office hours ICU admissions following elective surgery were associated with an increased risk of infection (P = 0.029), blood transfusion (P = 0.020), total parental nutrition (P0.001) and unplanned re-operations (P = 0.027). Out-of-office hours ICU admissions were also associated with an increased hospital length-of-stay, with (1.74 days longer, P0.0001) and without (2.8 days longer, P0.001) adjusting for severity of acute and chronic illnesses and inter-hospital transfers (12.3 versus 9.8%, P = 0.024). Hospital mortality (1.2 versus 0.7%, P = 0.111) was low and similar between both groups.Out-of-office hours ICU admissions following elective surgery is common and associated with serious post-operative complications culminating in significantly longer hospital length-of-stays and greater transfers with important patient and health economic implications.

Cardiac surgery is increasingly performed on elderly patients with multiple comorbid conditions, but the determinants of the relationship between cost and survival time after cardiac surgery for patients with a serious cardiac condition remain uncertain. Using the long-term outcome data of a cohort study on adult cardiac surgical patients, the relationship between cost and survival time after cardiac surgery from a hospital service perspective was determined. The total cost for each patient was estimated by the costs of the surgical procedures, intra-aortic balloon pump utilisation, operating theatre utilisation, blood products, intensive care unit stay and cumulative hospital stay up to a median follow-up time of 30 months. Of the 2131 patients considered in this study, a total cost >A$100,000 per life-year after cardiac surgery was observed only in 171 patients (8.0%, 95% confidence interval 6.9 to 9.3%). Age, Charlson Comorbidity Index and EuroSCORE were all related to the cost per life-year after cardiac surgery, but EuroSCORE (odds ratio 1.26 per score increment, 95% confidence interval 1.18 to 1.35, P=0.001) was, by far, the most important determinant and explained 32% of the variability in cost per life-year after cardiac surgery. Patients with a high EuroSCORE were associated with a substantially longer length of intensive care unit stay and cumulative hospital stay, as well as a shorter survival time after cardiac surgery compared to patients with a lower EuroSCORE. Of all the subgroups of patients examined, only patients with a EuroSCORE >5 were consistently associated with a cost >A$100,000 per life-year (cost per life-year $183,148, 95% confidence interval 125, 394 to 240, 902).

The aim of this paper was to explore the issue of consent when considering the use of a life saving but not necessarily restorative surgical intervention for severe traumatic brain injury. A previous study has investigated the issue amongst 500 healthcare workers by using a two-part structured interview to assess opinion regarding decompressive craniectomy for three patients with varying injury severity. A visual analogue scale was used to assess the strengths of their opinions both before and after being shown objective outcome data. Opinions were assessed in a number of scenarios, one of which was that the participants themselves were the injured party. The implication, which was clearly stated, was whether they would provide consent for the procedure to be performed. The study demonstrated that participants were relatively risk aversive in regards to survival with severe disability especially when the injury was severe and there was high probability of that outcome occurring. This finding was not however universal and a minority of participants would provide consent even when the possibility of survival with severe disability was very high. The obvious difficulty comes when considering consent in patients who are unable to express their wishes. In order to address this issue we propose a model of consent based on a balance of the various factors that seem to be of material relevance. These include the severity of the injury, the willingness or otherwise to accept survival with severe disability and the willingness to “risk” the possibility of an unacceptable outcome in order to achieve an acceptable outcome.

The association of deficiency in total body iron with an increased risk of reactive thrombocytosis is well known, but whether functional iron deficiency' is also associated with reactive thrombocytosis is unknown. This retrospective case-control study assessed the relationships between functional iron deficiency, reactive thrombocytosis and risk of thromboembolism. A total of 150 patients with reactive thrombocytosis (platelet count >400 × 109/I) and 343 controls (platelet count >400 × 109/I) were selected from the hospital laboratory database system. Patients with haematological disease or recent chemotherapy were excluded. Reactive thrombocytosis, infection, and an elevated C-reactive protein (CRP) concentration were all significantly more common in patients with functional iron deficiency than in those without functional iron deficiency (all P

Summary Standard cardiorespiratory monitoring may fail to detect occult tissue ischaemia. This study assessed whether a near infra-red spectroscopy tissue oxygen saturation monitor (InSpectra™) could detect progressive peripheral tissue ischaemia and whether hyperoxia may confound tissue oxygen saturation measurement. Tissue oxygen and arterial oxygen saturations were measured continuously in 30 healthy volunteers, first during a period of progressive increase in inspired oxygen concentration and subsequently during two periods of low- and high-pressure limb ischaemia. Increasing inspired oxygen concentration was associated with a small increase in mean (SD) tissue oxygen saturation of 5.3 (7.1) %, reaching a plateau between 30% and 40% inspired oxygen. The rate and magnitude of decreases in tissue oxygen saturations were greater during high- than low-pressure ischaemia with a mean (SD) desaturation rate of 3.3 (0.9) vs 1.8 (0.8) %.min-1 (p < 0.01). The dose-related association and lack of confounding by hyperoxia suggest that tissue oxygen saturation monitoring may be a useful adjunct to detect occult ischaemia.

Background Recent evidence suggests that neuraxial and regional anaesthesia may influence the progression of the underlying malignant disease after surgery. Methods This retrospective cohort study assessed whether neuraxial anaesthesia would affect the progression of cervical cancer in 132 consecutive patients who were treated with brachytherapy in a tertiary cancer centre in Australia. Results Age, American Society of Anesthesiologists status, International Federation of Gynecologists and Obstetricians (FIGO) cancer staging, invasion into the uterus, tumour volume, and tumour cell types were not significantly different between patients who received neuraxial and general anaesthesia during their first brachytherapy treatment. The use of neuraxial anaesthesia during the first brachytherapy was not associated with a reduced risk of local or systemic recurrence [hazard ratio (HR) 0.95, 95% confidence interval (CI) 0.54–1.67; P=0.863], long-term mortality from tumour recurrence (HR 1.46, 95% CI 0.75–2.84; P=0.265), or all-cause mortality (HR 1.46, 95% CI 0.81–2.61; P=0.209), after adjusting for other prognostic factors. Tumour recurrence and long-term survival were only significantly associated with the tumour cell type, tumour volume, and FIGO tumour staging. Sensitivity analyses using proportions of all brachytherapy sessions performed under neuraxial anaesthesia also did not show any beneficial effects of neuraxial anaesthesia on tumour recurrence and long-term survival. Conclusions Using neuraxial anaesthesia during brachytherapy for patients with cervical cancer was not associated with a reduced risk of tumour recurrence and mortality when compared with general anaesthesia.

IntroductionDiffuse axonal injury (DAI) detected on magnetic resonance imaging (MRI) may be useful to predict outcome after traumatic brain injury (TBI).MethodsThis study compared the ability of the International Mission for Prognosis and Analysis of Clinical Trials (IMPACT) prognostic model with DAI on MRI, to predict 18 months neurological outcome in 56 patients who had required a decompressive craniectomy after TBI.Of the 56 patients included in the study (19 scans occurred within 14 days; median time for all patients 24 days, interquartile range 14–42), 18 (32%) had evidence of DAI on the MRI scans. The presence of DAI on the MRI diffusion-weighted (DW), T2*-weighted-gradient echo and susceptibility-weighted (SWI) sequences was associated with an increased risk of unfavourable outcome at 18 months compared to those without DAI (44% vs. 17%, difference=27%, 95% confidence interval 2.4%–46.7%; p=0.032), particularly when brainstem was involved. However, neither the grading (I to IV) nor the number of brain regions with DAI was as good as the IMPACT model in discriminating between patients with unfavourable and favourable outcome (area under the receiver-operating-characteristic curve: 0.625 and 0.621 vs 0.918, respectively; pConclusionThe prognostic significance of DAI on MRI may, in part, be captured by the IMPACT prognostic model. More research is needed before MRI should be routinely used to prognosticate outcomes of patients with TBI requiring decompressive craniectomy.

Background Critical illness leading to prolonged length of stay (LOS) in an intensive care unit (ICU) is associated with significant mortality and resource utilization. This study assessed the independent effect of ICU LOS on in-hospital and long-term mortality after hospital discharge. Methods Clinical and mortality data of 22 298 patients, aged 16 yr and older, admitted to ICU between 1987 and 2002 were included in this linked-data cohort study. Cox's regression with restricted cubic spline function was used to model the effect of LOS on in-hospital and long-term mortality after adjusting for age, gender, acute physiology score (APS), maximum number of organ failures, era of admission, elective admission, Charlson's co-morbidity index, and diagnosis. The variability each predictor explained was calculated by the percentage of the χ2 statistic contribution to the total χ2 statistic. Results Most hospital deaths occurred within the first few days of ICU admission. Increasing LOS in ICU was not associated with an increased risk of in-hospital mortality after adjusting for other covariates, but was associated with an increased risk of long-term mortality after hospital discharge. The variability on the long-term mortality effect associated with ICU LOS (2.3%) appeared to reach a plateau after the first 10 days in ICU and was not as important as age (35.8%), co-morbidities (18.6%), diagnosis (10.9%), and APS (3.6%). Conclusions LOS in ICU was not an independent risk factor for in-hospital mortality, but it had a small effect on long-term mortality after hospital discharge after adjustment for other risk factors.

Healthcare utilisation can affect quality of life and is important in assessing the cost‐effectiveness of medical interventions. A clinical database was linked to two Australian state administrative databases to assess the difference in incidence of healthcare utilisation of 19 921 patients who survived their first episode of critical illness. The number of hospital admissions and days of hospitalisation per patient‐year was respectively 150% and 220% greater after than before an episode of critical illness (assessed over the same time period). This was the case regardless of age or type of surgery (i.e. cardiac vs non‐cardiac). After adjusting for the ageing effect of the cohort as a whole, there was still an unexplained two to four‐fold increase in hospital admissions per patient‐year after an episode of critical illness. We conclude that an episode of critical illness is a robust predictor of subsequent healthcare utilisation. Refereed/Peer-reviewed

Diagnosis of bloodstream infections in critically ill patients is difficult. This case control study involved a total of 22 patients with confirmed bloodstream infections and 44 concurrent controls from an intensive care unit in Western Australia. We aimed to assess whether eosinopenia and C-reactive protein are useful markers of bloodstream infections in critically ill patients. The patients with bloodstream infections had a more severe disease and a longer length of intensive care unit (10.7 vs 4.0 days, P=0.001) and hospital stay (40.9 vs 17.9 days, P=0.015) than the controls. Univariate analyses showed that C-reactive protein (area under the receiver operating characteristic curve 0.847, 95% confidence internal (CI) 0.721 to 0.973), eosinophil counts (area under the receiver operating characteristic curve 0.849, 95% CI 0.738 to 0.961) and fibrinogen concentrations (area under the receiver operating characteristic curve 0.730, 95% CI 0.578 to 0.882) were significant markers of bloodstream infections. C-reactive protein concentration was, however, the only significant predictor in the multivariate analysis (odds ratio 1.21 per 10 mgH increment, 95% CI 1.01 to 1.39, P=0.007). C-reactive protein concentration appears to be a better marker of bloodstream infections than eosinopenia in critically ill patients. A large prospective cohort study is needed to assess whether eosinopenia is useful in addition to C-reactive protein concentrations as a marker of bloodstream infections.

The burgeoning problem of obesity is seen most profoundly in older populations. Despite the dramatic increase in bariatric surgery rates over the last 20 years, weight reduction surgery is largely restricted to younger patients.This retrospective, longitudinal, self-matched, population-based cohort study assessed the incidence and outcomes of all patients undergoing bariatric surgery who were ≥55 years old in Western Australia between 2007 and 2011. The mean preoperative and post-operative follow-up periods were 2.5 years and 3.4 years, respectively.Of the 12 062 bariatric surgical operations recorded during the study period, 2179 (18.1%) were performed in patients aged ≥55 years old. Older bariatric patients were statistically more likely to require longer hospital admissions (2.85 versus 2.65 days, P0.001), have post-operative complications (12.0 versus 6.3%, P0.001) and require intensive care admissions (8.2 versus 4.3%, P = 0.001) compared to patients55 years old. However, both 30-day (no deaths in the older cohort) and long-term mortality rates (1.07 versus 0.42 deaths per 1000 patient-years, P = 0.10) remained relatively low. All-cause long-term hospitalization rates were also significantly reduced (P0.001) after bariatric surgery for patients who were older than 55 years compared to before surgery.Despite older age being associated with a higher risk of complications and longer hospital stays, there was a reduction in subsequent overall hospitalizations for older patients after bariatric surgery, suggesting that bariatric surgery may still confer health benefits to carefully selected obese older patients who cannot achieve weight loss by other means.

Background Optimal thromboprophylaxis after cardiac surgery is uncertain. This systematic review aimed to define the incidence and risk factors for deep vein thrombosis ( DVT ), fatal and nonfatal pulmonary embolism ( PE ), and assess whether venous thromboembolism ( VTE ) prophylaxis was effective in reducing VTE without complications after cardiac surgery. Methods and Results Two reviewers independently searched and assessed the quality and outcomes of randomized, controlled trials ( RCT s) and observational studies on VTE after cardiac surgery in the MEDLINE , EMBASE , and Cochrane controlled trial register (1966 to December 2014). Sixty‐eight studies provided data on VTE outcomes or complications related to thromboprophylaxis after cardiac surgery. The majority of the studies were observational studies (n=49), 16 studies were RCT s, and 3 were meta‐analyses. VTE prophylaxis was associated with a reduced risk of PE (relative risk [ RR ], 0.45; 95% confidence interval [ CI ], 0.28–0.72; P =0.0008) or symptomatic VTE ( RR , 0.44; 95% CI , 0.28–0.71; P =0.0006) compared to the control without significant heterogeneity. Median incidence (interquartile range) of symptomatic DVT , PE , and fatal PE were 3.2% (0.6–8.1), 0.6% (0.3–2.9), and 0.3% (0.08–1.7), respectively. Previous history of VTE , obesity, left or right ventricular failure, and prolonged bed rest, mechanical ventilation, or use of a central venous catheter were common risk factors for VTE . Bleeding or cardiac tamponade requiring reoperation owing to pharmacological VTE prophylaxis alone, without systemic anticoagulation, was not observed. Conclusions Unless proven otherwise by adequately powered RCT s, initiating pharmacological VTE prophylaxis as soon as possible after cardiac surgery for patients who have no active bleeding is highly recommended.

Trauma patients are at a high risk of both bleeding and thromboembolism. This study assessed whether conventional coagulation blood tests were reliable predictors of an increased in vitro thrombotic and bleeding tendency of trauma and non-trauma patients. Conventional coagulation blood tests and thromboelastographs of 63 trauma and 63 randomly selected, critically ill non-trauma patients were compared. Increased in vitro thrombotic and bleeding tendencies were defined by a maximum amplitude >72 mm or an angle >74° on the thromboelastograph and a maximum amplitude < 54 mm or an angle 9 /l) and low fibrinogen concentrations (1.5) and activated Partial Thromboplastin Time (>40 seconds) were, however, not significantly associated with an increased in vitro thrombotic or bleeding tendency. In conclusion, in vitro thrombotic tendency was more common than bleeding tendency in critically ill trauma and non-trauma patients. Platelet counts and fibrinogen concentrations were better predictors of increased in vitro thrombotic and bleeding risks than International Normalized Ratio or activated Partial Thromboplastin Time.

Two alternative approaches for transcatheter aortic valve implantation (TAVI) exist for patients unsuitable for the transfemoral approach; the transapical and the transaortic approaches. It is unclear as to which approach has superior short-term outcomes. A systematic review and meta-analysis was performed to answer this question. Mortality was equivalent in the 2 groups. There was a trend toward a lower rate of stroke in the transaortic group (0.9% vs 2.1%) but this was not statistically significant. Conversion to surgical aortic valve replacement, paravalvular leak, pacemaker requirement, and major bleeding occurred at equivalent rates.

There continues to be considerable amount of interest in decompressive craniectomy however its use is controversial. It is technically straightforward however it is not without significant complications and although there is currently unequivocal evidence available that it can be a life saving intervention, evidence that outcome is improved over and above standard medical therapy is less forthcoming. This narrative review considers the current role of decompressive craniectomy in the management of neurological emergencies and focuses on four specific questions, namely; (i) Is the decompressive craniectomy a life saving procedure? (ii) Does decompressive craniectomy improve outcome? (iii) Are there any risks associated with decompressive craniectomy? (iv) How do patients feel about their eventual outcome? Finally the future directions for the use of decompressive craniectomy are explored.

Given the considerable interest in the use of evidence-based medicine to guide clinical practice, it is surprising that the results of a recent randomized controlled trial have been met with such a limited response. The DECompressive CRAniectomy study investigators have recently published the results of a landmark trial in neurosurgery, comparing early decompressive craniectomy with standard medical therapy in patients who developed intracranial hypertension after diffuse closed traumatic brain injury (TBI). This is the first ever randomized controlled trial investigating the surgical management of adult patients with severe TBI. The trial clearly demonstrated that early decompression did not provide clinical benefit; however, rather than having a significant impact on clinical practice, it has been almost uniformly criticized. While there were some problems with randomization and crossover, we feel that the trial has been somewhat misinterpreted and in this article we address some of the key issues.

The rule of rescue describes the powerful human proclivity to rescue identified endangered lives, regardless of cost or risk. Deciding whether or not to perform a decompressive craniectomy as a life-saving or ‘rescue’ procedure for a young person with a severe traumatic brain injury provides a good example of the ethical tensions that occur in these situations. Unfortunately, there comes a point when the primary brain injury is so severe that if the patient survives they are likely to remain severely disabled and fully dependent. The health resource implications of this outcome are significant. By using a web-based outcome prediction model this study compares the long-term outcome and designation of two groups of patients. One group had a very severe injury as adjudged by the model and the other group a less severe injury. At 18 month follow-up there were significant differences in outcome and healthcare requirements. This raises important ethical issues when considering life-saving but non-restorative surgical intervention. The discussion about realistic outcome cannot be dichotomised into simply life or death so that the outcome for the patient must enter the equation. As in other ‘rescue situations’, the utility of the procedure cannot be rationalised on a mere cost–benefit analysis. A compromise has to be reached to determine at what point either the likely outcome would be unacceptable to the person on whom the procedure is being performed or the social utility gained from the rule of rescue intervention fails to justify the utilitarian value and justice of equitable resource allocation.

Furosemide, a potent loop diuretic, is frequently used in different stages of acute kidney injury, but its clinical roles remain uncertain. This review summarises the pharmacology of furosemide, its potential uses and side effects, and the evidence of its efficacy. Furosemide is actively secreted by the proximal tubules into the urine before reaching its site of action at the ascending limb of loop of Henle. It is the urinary concentrations of furosemide that determine its diuretic effect. The severity of acute kidney injury has a significant effect on the diuretic response to furosemide; a good 'urinary response' may be considered as a 'proxy' for having some residual renal function. The current evidence does not suggest that furosemide can reduce mortality in patients with acute kidney injury. In patients with acute lung injury without haemodynamic instability, furosemide may be useful in achieving fluid balance to facilitate mechanical ventilation according to the lung-protective ventilation strategy.

Citrate, as an anticoagulant for continuous renal replacement therapy in critically ill patients, has some potential advantages over heparin, including a prolonged dialysis filter life and reduced risk of bleeding. The key parameter involved in monitoring the adequacy and safety of citrate anticoagulation during continuous renal replacement therapy pertains to the ionised and total plasma calcium levels. We report a case of severe systemic hypocalcaemia during continuous renal replacement therapy with citrate anticoagulation resulting from relentless sequestration of calcium due to undiagnosed evolving rhabdomyolysis. Although excessive systemic citrate accumulation can also cause hypocalcaemia, this complication was not observed in our patient. While an acceptable lower limit of ionised calcium remains unknown, severe rhabdomyolysis needs to be considered when a patient's ionised calcium levels are not responsive to standard calcium replacement therapy during continuous renal replacement therapy using citrate anticoagulation in critically ill patients.

Methicillin-resistant Staphylococcus aureus (MRSA) infection is an increasing threat to critically ill patients in many intensive care units. MRSA bacteraemia is an extreme form of MRSA infection and is a significant cause of morbidity and mortality. This case control study aimed to assess the risk factors and outcomes of MRSA bacteraemia compared to methicillin-susceptible Staphylococcus aureus (MSSA) bacteraemia. A total of 21 MRSA bacteraemia and 60 randomly selected MSSA bacteraemia episodes, admitted to the intensive care unit at Royal Perth Hospital between 1997 and 2007, were considered. There was a suggestion that hospitalisation within the preceding six months (P=0.087) and residence in a long-term care facility (P=0.065) were associated with a higher risk of MRSA bacteraemia. MRSA bacteraemia was more often treated with antibiotics to which the pathogen was not susceptible in vitro (38.1% vs 0%, P=0.001), resulting in a longer duration of fever (median 7.0 vs 2.0 days, P=0.009) and bacteraemia (mean 3.2 vs 0.6 days, P=0.005) and a higher incidence of metastatic seeding of infection (52.4% vs 21.7%, P=0.012) as compared to MSSA bacteraemia. While in-hospital mortality between MRSA and MSSA was similarly high (47.6% vs 38.3% for MRSA and MSSA respectively, P=0.607), a significant proportion of the patients who had MRSA bacteraemia died within five years of hospital discharge (36.4%, hazard ratio 26.0, 95% confidence interval 1.90 to 356.7, P=0.015). Infections contributed to 75% of the deaths after hospital discharge in patients who had an episode of MRSA bacteraemia. MRSA bacteraemia carries a much worse long-term prognosis than MSSA bacteraemia and that could be explained by recurrent MRSA infections and residual confounding.

Intravenous magnesium has been used to prevent and treat many different types of cardiac arrhythmia. It has diverse electrophysiological actions on the conduction system of the heart; including prolonging sinus node recovery time, and reducing automaticity, atrioventricular nodal conduction, antegrade and retrograde conduction over an accessory pathway, and His-ventricular conduction. Intravenous magnesium can also homogenise transmural ventricular repolarisation. Because of its unique and diverse electrophysiological actions, intravenous magnesium has been reported to be useful in preventing atrial fibrillation and ventricular arrhythmias after cardiac and thoracic surgery; in reducing the ventricular response in acute onset atrial fibrillation, including for patients with Wolff-Parkinson-White syndrome; in the treatment of digoxin induced supraventricular and ventricular arrhythmias, multifocal atrial tachycardia, and polymorphic ventricular tachycardia or ventricular fibrillation from drug overdoses. Intravenous magnesium is, however, not useful in monomorphic ventricular tachycardia and shock-resistant ventricular fibrillation. Large randomised controlled studies are needed to confirm whether intravenous magnesium can improve patient centre outcomes in different cardiac arrhythmias.

This study aimed to describe the patient characteristics and prehospital factors associated with an ICU admission from the ED. There is a paucity of information about the early recognition of critical illness by paramedics; especially in the Australian prehospital setting.

Dear Editor, We read with interest the recent paper published in Acta Neurochirurgica by Li et al. [14]. In this paper, the authors have compared the outcome of craniotomy versus decompressive craniectomy in patients who have had an acute subdural hematoma evacuated. This is a well-written paper that addresses the important and topical issue of the role of decompressive craniectomy in the management of patients with severe traumatic brain injury and the authors should be congratulated. We would however, like to raise a few issues for further discussion. In the first instance, the authors concluded that “This is the first time that the CRASH head injury prediction model has been applied in a cohort of patients with traumatic ASDH”. This statement was incorrect. A review of the recent literature published in Acta Neurochirurgica would not support this statement [8]. Indeed, a wider review of the literature would reveal that this methodology has been used in a number of studies not only when considering evacuation of a mass lesion but also in the context of diffuse cerebral swelling [5, 6]. In our previous work, we stratified patients according to injury severity using a method that is similar to the standard method by which a prediction model is calibrated [2]. By comparing the predicted risk of an unfavorable outcome with the observed outcomewe can actually see differences between the predicted and observed risks of unfavorable outcomes across the full spectrum of severity of illness, rather than just the overall difference by the standardized morbidity ratio. Secondly, we can see from their results that the patients who had decompressive craniectomy were significantly sicker than the patients who had had a craniotomy.We would recommend the authors conduct a multivariable analysis to assess whether decompressive craniectomy was better than craniotomy, after adjusting for the CRASH-predicted risks of unfavorable outcome. Although the confidence interval of the two standardized morbidity ratios overlapped with one another, this did not confirm that these two estimates were statistically different. Because the standardized morbidity ratios between the groups appeared different, the authors should analyze the differences in their standardized morbidity ratio by a formal statistical testing before concluding that they were not different. Finally, this study was underpowered to detect a difference in outcomes between the two groups. At the very least, the risk of a type II error should be emphasized and any extrapolation of the negative results should be taken with extreme caution. Unfortunately, the authors did not highlight this important limitation in their discussion of the limitations of the study. Notwithstanding these issues, we would agree with the authors that one of the major confounding issues when interpreting the results of the many studies that have investigated the role of decompressive craniectomy is the failure to adjust for initial injury severity. Using the CRASH model to stratify patients according to injury severity provides an objective assessment of outcome (Fig. 1) and while we would agree with the CRASH collaborators that the use of this model should only be used to support and not replace clinical judgment, we feel that it can provide supportive S. Honeybul (*) : C. R. P. Lind Department of Neurosurgery, Sir Charles Gairdner Hospital and Royal Perth Hospital, Perth, Western Australia, Australia e-mail: stephen.honeybul@health.wa.gov.au

Methods: Acute admissions, excluding those managed entirely by theEmergencyDepartmentor aday treatment area, to a400-bed tertiary referral hospital between01/01/2008and31/12/2011were identified from administrative data. Data for the first admission by each patient was merged with emergency call (Respond Medical Emergency Team or Respond Blue) data. Outcomes were hospital discharge destination and death, either in hospital or notified to the hospital, in the six months following the date of admission. Results: There were 43,385 admission episodes. During 1208 (2.8%) of these one or more medical emergency calls occurred. Median time to the first call was 3.2 days (IQR 1.2–9.0) and 91 (8%) involved cardiac arrest. Emergency call patients more often died in hospital (22% vs. 1%, P

Optimising perioperative haemodynamic status may reduce postoperative complications. In this prospective prevalence study, we investigated the associations between standard haemodynamic parameters and a low central venous oxygen saturation (ScvO2) in patients after major surgery. A total of 201 patients requiring continuous arterial and central venous pressure monitoring after major surgery were recruited. Simultaneous arterial and central venous blood gases, haemodynamic and biochemical data and perfusion index were obtained from patients at a single time-point within 24 hours of surgery. A low ScvO2 (2) and carbon dioxide tensions (PaCO2) were all associated with a low ScvO2 in the univariate analyses. In the multivariate analysis, only a higher perfusion index (odds ratio [OR] 0.87, 95% confidence interval [CI] 0.78 to 0.98), PaO2 (OR 0.98 per mmHg increment, 95% CI 0.97 to 0.99) and PaCO2 (OR 0.88 per mmHg increment, 95% CI 0.82 to 0.95) and a lower central venous pressure (OR 1.14 per mmHg increment, 95% CI 1.04 to 1.25) were significantly associated with a reduced risk of a low ScvO2, all in a linear fashion. In conclusion, PaO2, PaCO2, perfusion index and central venous pressure were significant predictors of a low ScvO2 in patients after major surgery including cardiac surgery, suggesting that ScvO2 should always be interpreted with the arterial blood gases and that liberal perioperative fluid therapy aiming at a high central venous pressure may be detrimental in optimising ScvO2.

Summary Bariatric surgery is a rapidly growing and dynamic discipline necessitating a specialised anaesthetic approach coordinating high-risk patients with appropriate postoperative intensive care (ICU) support. The relationship between the anaesthetic and ICU utilisation after bariatric surgery is poorly understood. All adult bariatric surgery patients admitted to any ICU over a five-year period between 2007 and 2011 in Western Australia were identified from hospital admission records and cross-referenced against the Western Australian Department of Health Data Linkage Unit database. During the study period 12,062 patients underwent bariatric surgery with 581 (4.8%) patients admitted to ICU immediately following surgery. The mean preoperative ASA score was 3.3 (standard deviation 1.1) with 76.9% of patients assessed by their anaesthetist for the first time on the day of surgery. Blood pathology (75%) and ECG (46.3%) were the most common preoperative investigations. Intraoperatively, 2.1% of patients had a grade 4 intubation with only 3.4% of patients requiring video-assisted intubation. Despite being deemed at high risk, 23.6% of patients were managed with 20 Gauge or smaller intravenous access. Anaesthetic complications were extremely uncommon (0.5% of all bariatric cases) but accounted for 9.7% of all postoperative ICU admissions. Smoking history, but not body mass index ( P=0.46), was the only significant prognostic factor for respiratory or airway-related anaesthetic complications ( P=0.012). In summary, the anaesthesia management of bariatric surgery varied widely in Western Australia, with smoking as the only significant preoperative risk factor for respiratory or airway-related anaesthesia complications.

Continuous haemodiafiltration (CVVHDF) is the main form of renal replacement therapy in critically ill patients with severe acute kidney injury. Clotting of the dialysers during CVVHDF is frequent, because most patients with acute kidney injury have an increased risk of bleeding and cannot be systemically anticoagulated. Using data from a randomised controlled trial comparing the efficiency of CVVHDF by placing the dialysis catheter tip at the right atrium or superior vena cava, this study assessed the patient factors associated with an increased risk of frequent clotting of the dialysers-defined by >1 dialysers clotted per day of CVVHDF. Of the 94 patients included in this study, a higher body mass index, a higher platelet count and a lower International Normalized Ratio were associated with an increased risk of frequent clotting of dialysers in the univariate analyses. Use of aspirin or clopidogrel, causes of acute kidney injury and daily dose of unfractionated heparin used were not significantly associated with the risk of frequent clotting of dialysers. In the multivariate parsimony model, only a high body mass index (odds ratio 1.06 per point increment, 95% confidence interval 1.01 to 1.13; P=0.036) and a high platelet count (odds ratio 1.84 per 100x10(9)/l increment, 95% confidence interval 1.17 to 2.91; P=0.009), both in a relatively linear fashion, were independently associated with an increased risk of frequent clotting of dialysers. Optimising the position of the tip of the dialysis catheter may be particularly important for patients with a high body mass index and platelet count in order to reduce frequent clotting of dialysers during CVVHDF.