Baseline parameters for rotational thromboelastometry (ROTEM®) in healthy women undergoing elective caesarean delivery: A prospective observational study in Australia

Formal reference ranges for rotational thromboelastometry (ROTEM®) in pregnancy have not been obtained in the recommended minimum sample size of 120. This prospective observational study aimed to establish baseline parameters in an Australian population of women undergoing elective caesarean delivery. The secondary aim was to compare these reference ranges with those from prior studies and the manufacturer.Women undergoing elective caesarean delivery at term were included if they were at term, with normal body mass index and had no conditions affecting coagulation. ROTEM® reference ranges were derived by calculating the 2.5 and 97.5 percentiles for INTEM/EXTEM/FIBTEM amplitude at 5 minutes (A5), amplitude at 15 minutes (A15), coagulation time (CT), maximum clot firmness (MCF), and clot formation time (CFT).Of 202 women screened, 132 met the inclusion criteria, having a mean age of 32.7 ± 5.0 years and median body mass index of 23.8 kg/m (interquartile range 21.5-26.4). The reference ranges for selected ROTEM® parameters were as follows: FIBTEM A5 (13-28 mm), FIBTEM CT (40-74 s), FIBTEM MCF (16-34 mm), EXTEM A5 (39-66 mm), EXTEM CT (43-69 s), INTEM A5 (38-63 mm).ROTEM® reference ranges for women with uncomplicated term pregnancies were reported as per the International Federation of Clinical Chemistry. The FIBTEM MCF and FIBTEM/EXTEM/INTEM amplitudes were higher in comparison to the manufacturer's reference ranges for the non-obstetric population. The EXTEM CT was shorter than the non-obstetric reference ranges. These ranges show an increase in coagulability during normal pregnancy compared to the non-pregnant reference ranges

Acute Kidney injury following liver transplantation: a systematic review of published predictive models

Acute kidney injury (AKI) is a frequent postoperative complication amongst liver transplant recipients and is associated with increased morbidity and mortality. This systematic review analysed the existing predictive models, in order to solidify current understanding. Articles were selected for inclusion if they described the primary development of a clinical prediction model (either an algorithm or risk score) to predict AKI post liver transplantation. The database search yielded a total of seven studies describing the primary development of a prediction model or risk score for the development of AKI following liver transplantation. The models span thirteen years of clinical research and highlight a gradual change in the definitions of AKI, emphasising the need to employ standardised definitions for subsequent studies. Collectively, the models identify a diverse range of predictive factors with several common trends. They emphasise the impact of preoperative renal dysfunction, liver disease severity and aetiology, metabolic risk factors as well as intraoperative variables including measures of haemodynamic instability and graft quality. Although several of the models address postoperative parameters, their utility in predictive modelling seems to be of questionable relevance. The common risk factors identified within this systematic review provide a minimum list of variables, which future studies should address. Research in this area would benefit from prospective, multisite studies with larger cohorts as well as the subsequent internal and external validation of predictive models. Ultimately, the ability to identify patients at high risk of post-transplant AKI may enable early intervention and perhaps prevention

Intraoperative cuff pressure measurements of supraglottic airway devices in the operating theatre : a prospective audit

Introduction : Supraglottic airway devices (SADs) are used for airway management for an estimated half of surgical patients worldwide in preference to endotracheal tubes. Intracuff pressure (P-INTRACUFF) measurement of SADs, is a monitoring parameter that may be overlooked in daily anesthetic practice. Correct intracuff pressures, with a recommended range of 40 to 60 cmH(2)O, are important from a clinical perspective to ensure adequate ventilation and to avoid complications due to cuff hypoinflation or hyperinflation. P(INTRACUFF )may be measured with a dedicated measuring device or by widely used estimation techniques such as manual palpation of the cuff, listening to the disappearance of an audible air leak or injection of a standard volume of air into the cuff via the pilot balloon. These estimation methods do not allow quantification of the P-INTRACUFF value to ensure an exact value at the recommended level.Methods : A prospective single-centre audit of P-INTRACUFF of 191 elective and emergency surgery patients with an SAD was performed measuring P-INTRACUFF values with a calibrated handheld cuff manometer following induction of anesthesia.Results : At the commencement of surgery, only 38.2% of the patients had a P-INTRACUFF within the recommended range, with measurements exceeding the upper limit of 60 cmH(2)O for 62 patients (32.5%). While 29.3% showed values of underinflation, patients who had a size 4 SAD were 3 times more likely to have a P(INTRACUFF )less than the lower limit of 40 cmH(2)O, compared to patients with a size 5 SAD (P=0.012). Patients who had a silicone SAD were 2.8 times more likely to have an inadequate P-INTRACUFF, compared to Polyvinyl Chloride SADs.Conclusions : Our results confirm the need for accurate measurement of SAD P-INTRACUFF using a cuff manometer to provide exact intracuff pressure measurements instead of subjective methods

Evaluation of perioperative predictors of acute kidney injury post orthotopic liver transplantation

Acute kidney injury (AKI) is a common complication following orthotopic liver transplantation. It is associated with increased morbidity and mortality, as well as increased healthcare costs. The aetiology of AKI post liver transplantation is multifactorial and understanding these factors is pivotal in developing risk stratification and prevention strategies. This study aims to investigate the preoperative and intraoperative factors that may be associated with AKI in patients undergoing liver transplantation at the Princess Alexandra Hospital, Brisbane, Queensland. In our study, retrospective data of 97 consecutive orthotopic liver transplantations performed between January 2009 and August 2012 were recorded. Univariate and multivariate analyses were performed to investigate the preoperative and intraoperative risk factors for the development of AKI in this cohort. In the cohort of 97 patients who underwent orthotopic liver transplantation, 24 patients (25%) developed postoperative AKI. Univariate analysis demonstrated that high preoperative body mass index and intraoperative noradrenaline use were both associated with AKI. Multivariate analysis demonstrated that high body mass index, high Model for End-stage Liver Disease score and intraoperative noradrenaline use were associated with AKI. Overall mortaility was 4.1% during the study period and was not significantly different between the two groups. The high incidence of AKI following liver transplantation in this study cohort highlights the importance of this issue. This study has identified several potential pre- and intraoperative risk factors, providing a focus for patient surveillance and future research