bluuebunny/crossref_metadata_2025 huggingface dataset:
Chewing Gum in the Preoperative Fasting Period: An Analysis of De-Identified Incidents Reported to Webairs
Authors: Shanmugam S. , Goulding G. , Gibbs N. M. , Taraporewalla K. , Culwick M.
Published: January 2019

The role of preoperative fasting is well established in current anaesthetic practice with different guidelines for clear fluids and food. However, chewing gum may not be categorised as either food or drink by some patients, and may not always be specified in instructions given to patients about preoperative fasting. The aim of this paper was to review anaesthesia incidents involving gum chewing reported to webAIRS to obtain information on the risks, if any, of gum chewing during the preoperative fasting period. There were nine incidents involving chewing gum reported between late 2009 and early 2015. There were no adverse outcomes from the nine incidents other than postponement of surgery in three cases and cancellation in one. In particular, there were no reports of aspiration or airway obstruction. Nevertheless, there were five cases in which the gum was not detected preoperatively and was found in the patient's mouth either intraoperatively or postoperatively. These cases of undetected gum occurred despite patient and staff compliance with their current preoperative checklists. While the risk of increased gastric secretions related to chewing gum preoperatively are not known, the potential for airway obstruction if the gum is not detected and removed preoperatively is very real. We recommend that patients should be specifically advised to avoid gum chewing once fasting from clear fluids is commenced, and that a specific question regarding the presence of chewing gum should be added to all preoperative checklists.
Autocalibrating Pulse Contour Analysis based on Radial Artery Applanation Tonometry for Continuous Non-Invasive Cardiac Output Monitoring in Intensive Care Unit Patients after Major Gastrointestinal Surgery—A Prospective Method Comparison Study
Authors: Wagner J. Y. , Langemann M. , Schön G. , Kluge S. , Reuter D. A. , Saugel B.
Published: January 2019

The T-Line® system (Tensys® Medical Inc., San Diego, CA, USA) non-invasively estimates cardiac output (CO) using autocalibrating pulse contour analysis of the radial artery applanation tonometry–derived arterial waveform. We compared T-Line CO measurements (TL-CO) with invasively obtained CO measurements using transpulmonary thermodilution (TD-CO) and calibrated pulse contour analysis (PC-CO) in patients after major gastrointestinal surgery. We compared 1) TL-CO versus TD-CO and 2) TL-CO versus PC-CO in 27 patients treated in the intensive care unit (ICU) after major gastrointestinal surgery. For the assessment of TD-CO and PC-CO we used the PiCCO® system (Pulsion Medical Systems SE, Feldkirchen, Germany). Per patient, we compared two sets of TD-CO and 30 minutes of PC-CO measurements with the simultaneously recorded TL-CO values using Bland–Altman analysis. The mean of differences (± standard deviation; 95% limits of agreement) between TL-CO and TD-CO was −0.8 (±1.6; −4.0 to +2.3) l/minute with a percentage error of 45%. For TL-CO versus PC-CO, we observed a mean of differences of −0.4 (±1.5; −3.4 to +2.5) l/minute with a percentage error of 43%. In ICU patients after major gastrointestinal surgery, continuous non-invasive CO measurement based on autocalibrating pulse contour analysis of the radial artery applanation tonometry–derived arterial waveform (TL-CO) is feasible in a clinical study setting. However, the agreement of TL-CO with TD-CO and PC-CO observed in our study indicates that further improvements are needed before the technology can be recommended for clinical use in these patients.
Factors Predicting Successful Discontinuation of Continuous Renal Replacement Therapy
Authors: Katayama S. , Uchino S. , Uji M. , Ohnuma T. , Namba Y. , Kawarazaki H. , Toki N. , Takeda K. , Yasuda H. , Izawa J. , Tokuhira N. , Nagata I. ,   for the Japanese Society of Education for Physicians and Trainees in Intensive Care (JSEPTIC) Clinical Trial Group
Published: January 2019

This multicentre, retrospective observational study was conducted from January 2010 to December 2010 to determine the optimal time for discontinuing continuous renal replacement therapy (CRRT) by evaluating factors predictive of successful discontinuation in patients with acute kidney injury. Analysis was performed for patients after CRRT was discontinued because of renal function recovery. Patients were divided into two groups according to the success or failure of CRRT discontinuation. In multivariate logistic regression analysis, urine output at discontinuation, creatinine level and CRRT duration were found to be significant variables (area under the receiver operating characteristic curve for urine output, 0.814). In conclusion, we found that higher urine output, lower creatinine and shorter CRRT duration were significant factors to predict successful discontinuation of CRRT.
Evaluation of Hospital-Wide Computerised Decision Support in an Intensive Care Unit: An Observational Study
Authors: Santucci W. , Day R. O. , Baysari M. T.
Published: January 2019

We conducted an observational study with interviews in a 12-bed general/neurological intensive care unit (ICU) at a teaching hospital in Sydney, Australia, to determine whether hospital-wide computerised decision support (CDS) embedded in an electronic prescribing system is used and perceived as useful by doctors in an ICU setting. Twenty doctors were shadowed by the observer while on ward rounds (33.6 hours) and non-ward rounds (28 hours) in the ICU. These doctors were also interviewed to explore views of CDS. We found that computerised alerts were triggered frequently in the ICU (n=166, in 59% of orders), less than half of the alerts were read by doctors and only four alerts resulted in a medication order being changed. Pre-written orders were utilised frequently, however reference material was rarely accessed. Interviews with doctors revealed a willingness to use CDS features; however the primary barrier to use was lack of customisation for the ICU setting. Doctors working in the ICU triggered a high number of alerts when prescribing, 40% more alerts than doctors working on general wards of the same hospital. Certain procedures in place in the ICU (e.g. daily microbiology ward rounds) made many alerts redundant in this setting. Lack of customisation for the ICU led to dissatisfaction with CDS and infrequent use of some CDS features.
Survey of Anaesthetists' Practice of Sedation for Gastrointestinal Endoscopy
Authors: Leslie K. , Allen M. L. , Hessian E. , Lee A. Y-S.
Published: January 2019

We conducted a survey of Australian specialist anaesthetists about their practice of sedation for elective and emergency gastroscopy, endoscopic retrograde cholangiopancreatography (ERCP), and colonoscopy. A 24-item survey was emailed to 1,000 anaesthetists in August 2015. Responses were received from 409 anaesthetists (response rate = 41%) with responses from 395 anaesthetists analysed. Pulse oximetry and oxygen administration were routine for all procedures for all respondents. Blood pressure was routinely measured by most respondents during gastroscopy (elective = 88%; emergency = 97%), ERCP (elective = 99%; emergency = 99%) and colonoscopy (elective = 91%; emergency = 98%). The airway was routinely managed with jaw lift or oral or nasal airway by 99%, 76% and 97% of respondents during gastroscopy, ERCP and colonoscopy, whereas in emergency procedures endotracheal intubation was routine in 49%, 64% and 17% of procedures. Propofol was routinely administered by 99% of respondents for gastroscopy and 100% of respondents for ERCP and colonoscopy. A maximum depth of sedation in which patients were unresponsive to painful stimulation was targeted by the majority of respondents for all procedures except for elective gastroscopy. These results may be used to facilitate comparison of practice in Australia and overseas, and give an indication of compliance by Australian anaesthetists with the relevant Australian and New Zealand College of Anaesthetists guideline.
Systemic Anticoagulation Related to Heparin Locking of Non-Tunnelled Venous Dialysis Catheters in Intensive Care Patients
Authors: Bong Y. C. , Walsham J.
Published: January 2019

Heparin locking of venous dialysis catheters is routinely performed in intensive care to maintain catheter patency when the catheters are not being used. Leakage of heparin into the circulation can potentially cause systemic anticoagulation and may present a risk to intensive care patients. To assess the effect of 5000 units per millilitre heparin locking of non-tunnelled dialysis catheters on systemic anticoagulation, we performed a prospective observational study of ten intensive care patients receiving heparin locking of dialysis catheters in an adult tertiary intensive care unit between July and September 2015. Activated partial thromboplastin time (APTT) was measured prior to, and three minutes after, heparin locking of catheter lumens with the manufacturer's recommended locking volume to assess the effect on systemic anticoagulation. Heparin locking of venous dialysis catheters resulted in a significant rise in APTT ( P=0.002). The median rise was by 56 seconds (interquartile range 30–166.5). Following heparin locking, 80% of patients had APTT values within or above the range associated with therapeutic anticoagulation. Heparin locking of non-tunnelled venous dialysis catheters can cause systemic anticoagulation in intensive care patients and therefore poses a potential risk to patient safety.
Local Anaesthetic Toxicity after Bilateral Thoracic Paravertebral Block in Patients Undergoing Coronary Artery Bypass Surgery
Authors: Ho A. M.-H. , Karmakar M. K. , Ng S. K. , Wan S. , Ng C. S. H. , Wong R. H. L. , Chan S. K. C. , Joynt G. M.
Published: January 2019

We conducted a small pilot observational study of the effects of bilateral thoracic paravertebral block (BTPB) as an adjunct to perioperative analgesia in coronary artery bypass surgery patients. The initial ropivacaine dose prior to induction of general anaesthesia was 3 mg/kg, which was followed at the end of the surgery by infusion of ropivacaine 0.25% 0.1 ml/kg/hour on each side (e.g. total 35 mg/hour for a 70 kg person). The BTPB did not eliminate the need for supplemental opioids after CABG in the eight patients studied. Moreover, in spite of boluses that were within the manufacturer's recommendation for epidural and major nerve blocks, and an infusion rate that was only slightly higher than what appeared to be safe for epidural infusion, potentially toxic total plasma ropivacaine concentrations were common. We also could not exclude the possibility that the high ropivacaine concentrations were contributing to postoperative mental state changes in the postoperative period. Also, one patient developed local anaesthetic toxicity after the bilateral paravertebral dose. As a result, the study was terminated early after four days. The question of whether paravertebral block confers benefits in cardiac surgery remains unanswered. However, we believe that the bolus dosage and the injection rate we used for BTPB were both too high, and caution other clinicians against the use of these doses. Future studies on the use of BTPB in cardiac surgery patients should include reduced ropivacaine doses injected over longer periods.
Anaesthetic Management of Obese Parturients: What is the Evidence Supporting Practice Guidelines?
Authors: Eley V. A. , van Zundert A. A. J. , Lipman J. , Callaway L. K.
Published: January 2019

Increasing rates of obesity in western populations present management difficulties for clinicians caring for obese pregnant women. Various governing bodies have published clinical guidelines for the care of obese parturients. These guidelines refer to two components of anaesthetic care: anaesthetic consultation in the antenatal period for women with a body mass index (BMI) > 40 kg/m2 and the provision of early epidural analgesia in labour. These recommendations are based on the increased incidence of obstetric complications and the predicted risks and difficulties in providing anaesthetic care. The concept behind early epidural analgesia is logical—site the epidural early, use it for surgical anaesthesia and avoid general anaesthesia if surgery is required. Experts support this recommendation, but there is weak supporting evidence. It is known that the management of labour epidurals in obese women is complicated and that women with extreme obesity require higher rates of general anaesthesia. Anecdotally, anaesthetists view and apply the early epidural recommendation inconsistently and the acceptability of early epidural analgesia to pregnant women is variable. In this topic review, we critically appraise these two practice recommendations. The elements required for effective implementation in multidisciplinary maternity care are considered. We identify gaps in the current literature and suggest areas for future research. While prospective cohort studies addressing epidural extension (‘top-up’) in obese parturients would help inform practice, audit of local practice may better answer the question “is early epidural analgesia beneficial to obese women in my practice?”.
Speckle Tracking Echocardiography in the Critically Ill: Enticing Research with Minimal Clinical Practicality or the Answer to Non-Invasive Cardiac Assessment?
Authors: Orde S. , Huang S. J. , Mclean A. S.
Published: January 2019

Echocardiography is developing rapidly. Speckle tracking echocardiography is the latest semi-automatic tool that has potential to quantitatively describe cardiac dysfunction that may be unrecognised by conventional echocardiography. It is a non-Doppler, angle-independent, feasible and reproducible method to evaluate myocardial function in both non–critically ill and critically ill populations. Increasingly it has become a standard measure of both left and right ventricle function in specific patient groups, e.g. chemotherapy-induced cardiomyopathy or pulmonary hypertension. To date there are few studies in the critically ill, predominantly in sepsis, yet all describe dysfunction beyond standard measures. Other areas of interest include heart–lung interactions, right ventricle function and twist and torsion of the heart. A word of caution is required, however, in that speckle tracking echocardiography is far from perfect and is more challenging, particularly in the critically ill, than implied by many published studies. It takes time to learn and perform and most values are not validated, particularly in the critically ill. We should be cautious in accepting that the latest software used in cardiology cohorts will automatically be the answer in the critically ill. Even with these limitations the technology is enticing and results fascinating. We are uncovering previously undescribed dysfunction and although it currently is essentially a research-based activity, there is great promise as a clinical tool as echocardiography analysis becomes more automated, and potentially speckle tracking echocardiography could help describe cardiac function in critical illness more accurately than is possible with current techniques.
The Effects of Residual Pump Blood on Patient Plasma Free Haemoglobin Levels Post Cardiac Surgery
Authors: Schotola H. , Wetz A. J. , Popov A. F. , Bergmann I. , Danner B. C. , Schöndube F. A. , Bauer M. , Bräuer A.
Published: January 2019

At the end of cardiopulmonary bypass, there are invariably several hundred millilitres of residual pump blood in the reservoir, which can either be re-transfused or discarded. The objective of this prospective observational study was to investigate the quality of the residual pump blood, focusing on plasma free haemoglobin (pfHb) and blood cell counts. Fifty-one consecutive patients were included in the study. Forty-nine units of residual pump blood and 58 units of transfused red blood cell (RBC) concentrates were analysed. The mean preoperative pfHb of the patients was 0.057 ± 0.062 g/l, which increased gradually to 0.55 ± 0.36 g/l on arrival in the intensive care unit postoperatively. On the first postoperative day, the mean pfHb had returned to within the normal range. Our data showed that haemoglobin, haematocrit, and erythrocyte counts of residual pump blood were approximately 40% of the values in standardised RBC concentrates. Plasma free haemoglobin was significantly higher in residual pump blood compared to RBC concentrates, and nearly twice as high as the pfHb in patient blood samples taken contemporaneously. Our findings indicate that residual pump blood pfHb levels are markedly higher compared to patients' blood and RBC concentrates, but that its administration does not significantly increase patients' pfHb levels.
Anaesthetists' Experiences with the Early Labour Epidural Recommendation for Obese Parturients: A Qualitative Study
Authors: Eley V. A. , Callaway L. K. , van Zundert A. A. J. , Lipman J. , Gallois C.
Published: January 2019

Caring for obese pregnant women presents challenges for all medical professionals. Despite a lack of supporting evidence, expert opinion and international guidelines suggest early labour epidural insertion for obese women. Anecdotally this is not supported by all anaesthetists. This qualitative study explored the experiences of anaesthetists regarding early epidural analgesia in obese parturients, to answer the research question: Are anaesthetists consistent in how they apply early epidural analgesia in obese parturients? Personal in-depth interviews with 42 specialist anaesthetists working in south-east Queensland, Australia, were completed between February and April, 2015. Leximancer™ text analysis software applied a validated algorithm to the data to identify themes and concepts. The major themes were explored by the first author to answer the research question. Three major themes were identified: the demands associated with caring for obese women; concern regarding the anaesthetic technique used in obese women; and the importance of communication with obstetric staff. Disagreement regarding interpretation and application of early epidural analgesia was identified within this group of anaesthetists. These anaesthetists were inconsistent in how they interpreted and applied early epidural analgesia for obese parturients, with some questioning the validity of the practice. The combination of uncertainty, urgency and technical difficulty presented by obese parturients provoked anxiety in these clinicians, particularly the anticipation of unplanned general anaesthesia. Consistent anaesthetic practice could improve the implementation of early epidural analgesia in obese parturients.
A Comparative Study of Tracheal Diameter in Caucasian and Chinese Patients
Authors: Tai A. , Corke C. , Joynt G. M. , Griffith J. , Lunn D. , Tong P. W. Y.
Published: January 2019

Ethnicity may be considered a factor when considering what size endotracheal tube to insert. In particular it has been suggested that Chinese patients have a smaller tracheal diameter, justifying the selection of smaller endotracheal tubes. We systematically evaluated transverse tracheal diameters in Chinese and Caucasian patients, utilising archived computer tomography images. A convenience sample of 100 Caucasian patients from Australia was compared with 100 Chinese patients from Hong Kong. Patients over 18 years of age who had undergone a computerised tomography scan of the neck and thorax, and also had accurate body height and weight recorded, were studied. The mean transverse diameter of the trachea measured at three levels was similar between the Chinese and Caucasian patients. At the narrowest measurement point, the immediate subcricoid transverse diameter, the unadjusted mean difference between male Chinese and Caucasian patients was small (1 mm, standard deviation 0.83 mm, P=0.01), and similarly small between female Chinese and Caucasian patients (1.5 mm, standard deviation 0.8 mm, P <0.01). Multivariate analysis demonstrated only a small influence related to ethnicity (12% relative contribution to the overall variance [R2] of the model), but substantial influence of height (40%) and sex (41%). Our findings do not support the practice of routinely selecting a smaller endotracheal tube size for Chinese patients on the basis that there is a difference related to the Chinese ethnic phenotype. Considerations regarding choice of endotracheal tube size should rather focus on patient sex and height.
Accuracy of Dispersing Tramadol Capsules for Oral Administration in Young Children
Authors: Kluger M. , Penrose S. , Bjorksten A. R. , Chalkiadis G. A.
Published: January 2019

Tramadol is used in children aged <12 years for analgesia, particularly for those at risk of obstructive sleep apnoea undergoing adenotonsillectomy. The Australian Therapeutic Goods Administration have strongly recommended that oral tramadol drops (100 mg/ml) not be used in children <12 years because of the risk of inadvertent overdose. The total mass of drug in a 10 ml bottle is 1000 mg. The only alternative preparation available is a 50 mg capsule that requires dispersion of a capsule's contents should smaller doses be required. The accuracy of this preparation has not been assessed. Twenty surgical ward nurses were asked to prepare a 15 mg dose of tramadol from a 50 mg capsule. The dose was within ±5% of 15 mg in 13 cases (65%) and within ±10% in 19 cases (95%) (range 13.9–17.1 mg). Despite the dose variability of this method of preparing tramadol, we consider it sufficiently accurate for clinical use. We also consider it safe, as even at the highest dose prepared, the variability would be unlikely to contribute to clinically significant side-effects or toxicity. Moreover, the maximal dose that could be administered is limited to the size of the capsule (50 mg).
Improved Hospital Mortality with a Low MET Dose: The Importance of a Modified Early Warning Score and Communication Tool
Authors: Mullany D. V. , Ziegenfuss M. , Goleby M. A. , Ward H. E.
Published: January 2019

Rapid response systems have been mandated for the recognition and management of the deteriorating patient. Increasing medical emergency team (MET) dose may be associated with improved outcomes. Large numbers of MET calls may divert resources from the program providing the service unless additional personnel are provided. To describe the implementation and outcomes of a multifaceted rapid response system (RRS) in a teaching hospital, we conducted an observational study. The RRS consisted of the introduction of a MET together with 1) redesign of the ward observation chart with the vital sign variables colour-coded to identify variation from normal; 2) mandated minimum frequency of vital sign measurement; 3) three formal levels of escalation based on the degree of physiological instability as measured by a modified early warning score (MEWS); 4) COMPASS© education and e-learning package with a two-hour face-to-face small group tutorial; 5) practise in escalation and communication using the ISBAR (Identify Situation, Background, Assessment, Response/Recommendation) communication tool. The primary outcome measures were all-cause hospital mortality rate and hospital standardised mortality ratio (HSMR) compared to peer hospitals calculated by the Health Round Table. There were 161,153 separations and 1,994 hospital deaths from July 2008 to December 2012. The MET call rate was 11.3 per 1000 separations in 2012. There was a decline in all-cause hospital mortality from 13.8 to 11 deaths/1000 separations. The HSMR decreased from 95.7 in 2008 to 66 in the second half of 2012 (below the three standard deviation control limit). A low MET dose may be associated with improved hospital mortality when combined with a MEWS and an intervention to improve communication.
Anaesthesia on the Western Front-Perspectives a Century Later
Authors: Mcdonald J. M.
Published: January 2019

This year, 2016, marks the centenary of some of the worst battles of World War I. It Is timely to reflect on the experiences of those who lived through those events, and the significant effects on the development of that occurred as a result. War has been a catalyst that has accelerated the development of medicine and surgery throughout history. The challenges of the Western Front, with its massive numbers of injured, saw progress In the understanding and management of trauma and shock, and significant Improvement in the provision of anaesthesia and the training of anaesthesia providers. The result was Increased anaesthetic safety for the civilian population after the war and further development of anaesthesia and resuscitation as a specialised area of medicine.
Left Ventricular Outflow Tract Obstruction—be Prepared!
Authors: Evans J. S. , Huang S. J. , McLean A. S. , Nalos M.
Published: January 2019

The current trend to treat hypotension in critically ill patients is to place a greater emphasis on inotropic support and less on fluid resuscitation in order to limit the potential harm from fluid overload. This combination may trigger left ventricular outflow tract obstruction (LVOTO) in susceptible patients. Although LVOTO is classically described in patients with hypertrophic cardiomyopathy it has been reported in other conditions including septic shock, apical ballooning syndrome, myocardial infarction, respiratory failure, and post valvular surgery. It is more common in the elderly, females, and in patients with hypertension, diabetes, and chronic vascular disease because of predisposing anatomical conditions such as left ventricular hypertrophy, small left ventricle size, sigmoid septum and alterations in the positions of the aortic and mitral valve annular planes. The onset of LVOTO is largely unpredictable due to a complex interplay between preload, afterload, heart rhythm and rate in susceptible patients. The consequences of missing this treatable condition may lead to life-threatening hypotension refractory to, or exacerbated by, a further increase in inotropic support. Dynamic LVOTO should be considered in any hypotensive intensive care patient. Echocardiography is perhaps the best tool to assess LVOTO and its underlying pathophysiology in the critically ill. Detection of LVOTO is a relatively simple task using a combination of two-dimensional, M-mode and spectral Doppler imaging by an operator alert to the possible diagnosis.
Haptoglobin and Free Haemoglobin during Cardiac Surgery—is there a Link to Acute Kidney Injury?
Authors: Wetz A. J. , Richardt E. M. , Schotola H. , Bauer M. , Bräuer A.
Published: January 2019

Acute kidney injury (AKI) is frequently observed after cardiac surgery (CS) with cardiopulmonary bypass (CPB). Multiple mechanisms underlie this phenomenon, including CPB-dependent haemolysis. Haemoglobin is released during haemolysis, and free haemoglobin (frHb) causes tubular cell injury after exceeding the binding capacity of haptoglobin (Hp). The objective of this study was to investigate the influence of perioperative changes in frHb and Hp levels on the incidence of CS-associated (CSA) AKI. After receiving local ethics committee approval and obtaining informed consent from our patients, we analysed the data pertaining to 154 patients undergoing CPB surgery. We recorded frHb and Hp concentrations pre-, intra- and postoperatively and defined AKI using the Kidney Disease Improving Global Outcomes (KDIGO) classification. We observed that frHb levels increased significantly during surgery and then decreased at ten hours thereafter and that Hp levels decreased during surgery and remained at low levels until the first postoperative day. We noted a moderate negative correlation between frHb and Hp levels. AKI was identified in 45.5% of patients; however, there was no significant difference in frHb or Hp levels between patients with and without AKI. We did not observe a relationship between frHb or Hp levels and CSA AKI and thus could not confirm the hypothesis that patients with higher baseline Hp concentrations experience a lower incidence of AKI than patients with lower baseline Hp concentrations.
Evaluating Team-based Inter-professional Advanced Life Support Training in Intensive Care—a Prospective Observational Study
Authors: Brewster D. J. , Barrett J. A. , Gherardin E. , O'Neill J. A. , Sage D. , Hanlon G.
Published: January 2019

Recent focus on national standards within Australian hospitals has prompted a focus on the training of our staff in advanced life support (ALS). Research in critical care nursing has questioned the traditional annual certification of ALS competence as the best method of delivering this training. Simulation and team-based training may provide better ALS education to intensive care unit (ICU) staff. Our new inter-professional team-based advanced life support program involved ICU staff in a large private metropolitan ICU. A prospective observational study using three standardised questionnaires and two multiple choice questionnaire assessments was conducted. Ninety-nine staff demonstrated a 17.8% (95% confidence interval 4.2–31, P=0.01) increase in overall ICU nursing attendance at training sessions. Questionnaire response rates were 93 (94%), 99 (100%) and 60 (61%) respectively; 51 (52%) staff returned all three. Criteria were assessed by scores from 0 to 10. Nurses reported improved satisfaction with the education program (9.4 to 7.1, P <0.001), as well as improvement in role understanding (8.7 and 9.1 versus 7.9 and 8.2, P <0.001) and confidence (8.4 and 8.8 versus 7.4 and 7.8, P <0.001) during ALS provision (outside ICU and inside ICU) following the course when compared to before the program. Doctors' only statistically significant improvement was in their confidence in ALS provision outside ICU (8.7 versus 8.1, P=0.04). The new program cost approximately an extra $16,500 in nursing salaries. We concluded that team-based, inter-professional ALS training produced statistically significant improvements in nursing attendance, satisfaction with ALS education, confidence and role understanding compared to traditional ALS training.
Rational Clinical Pathology Assessment in the Intensive Care Unit
Authors: Rachakonda K. S. , Parr M. , Aneman A. , Bhonagiri S. , Micallef S.
Published: January 2019

Blood tests are ordered on a daily basis in intensive care units (ICU). There are no widely accepted guidelines for testing requirements. This study investigated the impact on ICU laboratory test costs of a multi-strategy change in practice involving routine blood testing. A single centre, prospective, interventional study using historical controls was undertaken to investigate the impact of ICU specialist authorisation of high-volume routine tests on ICU laboratory test costs. Prior to commencement of the study, ICU nursing and junior ICU doctors were able to order tests. During the six-month intervention period, the ICU specialists authorised routine blood tests. Adverse events related to not performing blood tests were also recorded. Overall ICU laboratory test costs decreased by 12.3% over the six months (P=0.0022 versus historical control) with a mean compliance of 51% with the test authorisation protocol. The costs of frequently ordered tests (classified as high-volume) decreased by 20% (P=0.0022 versus historical control). These accounted for an average of 54 ± 3% of the overall ICU blood test costs (blood gas analyses 17%, simple chemistry tests consisting of electrolytes, liver function, calcium, phosphate, magnesium 14%, coagulation 12% and full blood count 11%). Two protocol-related adverse events were recorded and judged as minor and were resolved by ordering tests during the day. No adverse patient outcomes resulted from these two events. Blood testing authorisation by an ICU specialist was associated with significant cost savings in ICU and no adverse patient outcomes.
Effect of Nicotine Replacement Therapy on Mortality, Delirium, and Duration of Therapy in Critically Ill Smokers: A Systematic Review and Meta-Analysis
Authors: Ng K. T. , Gillies M. , Griffith D. M.
Published: January 2019

Nicotine replacement therapy is widely used in critically ill smokers and its effect on delirium, mortality and duration of intensive care unit (ICU) admission is unknown. The aims of this review were to determine whether the management of nicotine withdrawal with nicotine replacement therapy reduces delirium, mortality or length of stay in critically ill smokers in ICU. The primary outcome was incidence of author-defined ICU delirium. Secondary outcomes were ICU or hospital mortality, ICU-free days at day 28, and ICU or hospital length of stay. We conducted a systematic review and meta-analysis of the data sources MEDLINE, EMBASE, CINAHL, and the Cochrane Database of Systematic Reviews for randomised controlled trials and observational studies. Clinical trials, observational studies and systematic reviews comparing nicotine replacement therapy with placebo or no treatment were included. Case reports, case series, non-systematic reviews and studies that involved children were excluded. Eight studies were eligible (n=2,636) for inclusion in the data synthesis. In a meta-analysis of observational studies, nicotine replacement therapy was associated with increased delirium (three studies; n=908; I2=0%; finite element method: odds ratio 4.03 [95% confidence interval 2.64, 6.15]; P <0.001). There was no difference in ICU mortality (three studies; n=1,309; P=0.10, I2=44%; finite element method: odds ratio 0.58; 95% confidence intervals 0.31– 1.10) and hospital mortality or 28-day ICU-free days. In the absence of high-quality data, nicotine replacement therapy cannot currently be recommended for routine use to prevent delirium or to reduce hospital or ICU mortality in critically ill smokers.
Administration of Anaesthetic Triggering Agents to Patients Tested Malignant Hyperthermia Normal and Their Relatives in New Zealand: An Update
Authors: Frei D. , Stowell K. M. , Langton E. E. , McRedmond L. , Pollock N. A. , Bulger T. F.
Published: January 2019

Testing for malignant hyperthermia in New Zealand involves two tests—in vitro contracture testing of excised lateral quadriceps muscle and DNA analysis. In vitro contracture testing is regarded as the gold standard in malignant hyperthermia diagnosis but several publications have questioned the reliability of a normal result. Analysis of 479 anaesthetic records in 280 patients or their descendants throughout New Zealand who had tested negative for malignant hyperthermia, demonstrated there was no evidence of malignant hyperthermia episodes in this group who had been administered anaesthetic triggering agents. A wide range of anaesthetics were used over the study period. Analysis of each anaesthetic record was undertaken using the malignant hyperthermia grading scale which determines the likelihood that an anaesthetic event represents a malignant hyperthermia episode. Confirmation of the negative results was further supported by normal DNA analysis of patients in 48% of anaesthetics. There are advantages to using inhalational agents in certain situations and although demonstrating a zero risk of a malignant hyperthermia episode is not statistically possible, evidence in this large series suggests that the risk of an episode in these patients is extremely low and may be negligible. We suggest that anaesthetic triggering agents can be used safely in patients with normal in vitro contracture tests, and in their descendants.
A Retrospective Observational Study of Patients with Dilated Cardiomyopathy Undergoing Non-Cardiac Surgery
Authors: Cook K. A. , MacIntyre P. A. , McAlpine J. R.
Published: January 2019

The perioperative risks and factors associated with adverse cardiac outcomes in patients with dilated cardiomyopathy undergoing non-cardiac surgery are unknown. Interrogation of the Nelson Hospital transthoracic echocardiogram database identified 127 patients with dilated cardiomyopathy who satisfied the study criteria and underwent non-cardiac surgery between June 1999 and July 2013. Demographic and clinical data along with postoperative death within 30 days or a major adverse cardiac event were retrieved and analysed. The mean age was 75.9 years. Seventy-one percent of the patients had severe impairment of left ventricular function and 35% had a severely dilated left ventricle. A major adverse cardiac event occurred in 18.1% of patients and 5.5% of patients died within 30 days of surgery. Increased surgical risk and absence of cerebrovascular disease were associated with adverse outcome (P <0.001, P <0.05, respectively). Forty-three and a half percent (43.5%) of patients undergoing high-risk surgery had an adverse outcome compared to 36.1% and 5.9% for moderate and low-risk surgery, respectively. A major adverse cardiac event was observed in 26.7% of patients with cardiovascular disease compared to 9.8% of patients without cardiovascular disease. We were unable to exclude an influence of other potential risk factors due to the retrospective observational nature of the study. These findings highlight a potential increase in complications with moderate or high surgical risk, whilst are reassuring in demonstrating the relative safety of low-risk surgery in this group of high-risk patients.
Dexmedetomidine-Associated Hyperthermia: A Retrospective Cohort Study of Intensive Care Unit Admissions between 2009 and 2016
Authors: Grayson K. E. D. , Tobin A. E. , Lim D. T. K. , Reid D. E. , Ghani M.
Published: January 2019

Dexmedetomidine-associated hyperthermia has not been previously studied. Analysis is warranted to determine whether this potentially dangerous complication is more prevalent than previously realised. We aimed to examine the association between dexmedetomidine and temperature ≥39.5°C, including patient characteristics, temporality and potential risk factors. We conducted a retrospective cohort study of all intensive care unit (ICU) admissions between 1 July 2009 and 31 May 2016 in a tertiary ICU in Australia. Temperature data was available for 9,782 ICU admissions. Dexmedetomidine was given intravenously to 611 (6.3%) patients at a dose of 0 to 1.5 g/kg/hour. Temperatures ≥39.5°C were recorded in 341 (3.5%) patients. Overall hospital mortality was 10.8% for all admissions and 29.3% for patients with temperatures ≥39.5°C. Dexmedetomidine exposure was more frequent in patients with temperature recordings ≥39.5°C compared to those with temperatures <39.5°C, 11.94% versus 2.94% (odds ratio [OR] 4.49; 95% confidence intervals [CI] 3.37, 5.92; P <0.001). The association was stronger for patients post-open heart surgery (OHS) with temperatures ≥39.5°C (OR 12.9; 95% CI 5.01, 31.62; P <0.001). Multivariate analysis showed an independent association between dexmedetomidine and a temperature ≥39.5°C in two particular patient groups: OHS (OR 2.72; 95% CI 1.1, 6.9; P <0.001), and obesity (OR 3.44; 95% CI 1.5, 7.9; P <0.001). Dexmedetomidine exposure is associated with an increased risk of hyperthermia. Possible risk factors are open heart surgery and obesity.
Liquid Ventilation
Authors: Leonard R. C.
Published: January 2019

This review describes the development of ventilation using perfluorocarbon liquids, and relates the remarkable physical properties of these compounds to their probable mechanisms of action in clinical disease.
Depth of Central Venous Catheter Insertion in Adults: An Audit and Assessment of a Technique to Improve Tip Position
Authors: Chalkiadis G. A. , Goucke C. R.
Published: January 2019

A technique of subclavian vein catheterization is described, tailored to the individual patient, to reduce the risk of right atrial placement with central venous catheter (CVC) insertion. Using data gathered retrospectively for Quality Improvement purposes, CVC tip location was assessed. The standard technique used in our cardiac anaesthesia unit at that time was to insert all CVCs to a depth of 15 cm from the skin. We then compared CVC tip location using a new “tailored” technique. The tailored method involved measuring the distance from the skin at which venepuncture occurred and using this distance to determine depth of CVC insertion. Using the tailored technique significantly decreases the frequency with which CVC tips enter the right atrium (P<0.001). An advantage of the tailored technique is that the distance between the most proximal and the distal ports of multi-lumen CVCs is taken into consideration, reducing the risk of extravasation via the proximal port.
An Evaluation of a New Analyser for Inhaled Nitric Oxide Administration
Authors: Carter B. , Holt M. , Tibballs J. , Hochmann M. , Osborne A.
Published: January 2019

We examined the ability of a new combined nitric oxide (NO)/nitrogen dioxide (NO2) electrochemical analyser (PrinterNOx, Micro Medical Limited, Chatham, Kent, England) to measure NO and NO2 concentrations.

The PrinterNOx was compared to a chemiluminescence analyser (42H, Thermo Environmental Instruments Inc, Franklin MA, U.S.A.). NO and NO2 were generated in a standard ventilator circuit using a paediatric ventilator (900C, Siemens Elema, Sweden) connected to an artificial lung (260li, TTL Test Lung, Michigan Instruments, MI, U.S.A.). Forty-four paired NO measurements ranging from 2.56 ppm to 74.6 ppm and 50 paired NO2 measurements ranging from 0.0 ppm to 5.39 ppm were obtained.

For the measurement of NO the PrinterNOx showed a tendency to overestimate the chemiluminescence analyser. Regression analysis showed a close relationship between the two analysers with r2=0.9981 and a regression equation of y=1.1658 x +0.0197. In the more clinically important range of 0-25 ppm, r2 increased to 0.9996 with a regression equation of y=1.1984 x -0.4657. Conversely the PrinterNOx underestimated the chemiluminescence analyser for the measurement of NO2. The regression equation describing this relationship was y=0.879 x -0.0447 (r2=0.9993).

We conclude that the PrinterNOx is of sufficient accuracy to be of clinical use in the administration of NO.
Intrathecal Pethidine: Pharmacology and Clinical Applications
Authors: Kee W. D. Ngan
Published: January 2019

Pethidine is the only member of the opioid family that has clinically important local anaesthetic activity in the dose range normally used for analgesia. Pethidine is unique as the only opioid in current use that is effective as the sole agent for spinal anaesthesia. In lower doses, intrathecal pethidine is also an effective analgesic for treating pain in labour. This paper reviews the pharmacology of intrathecal pethidine and clinical experience reported to date. Articles reviewed include those identified by a Medline search using keywords “intrathecal” or “spinal anaesthesia/ anesthesia” and “pethidine” or “meperidine”. Reference lists from identified papers were scrutinized to identify further relevant articles.
Contamination of Propofol Infusions in the Intensive Care Unit: Incidence and Clinical Significance
Authors: Webb S. A. R. , Roberts B. , Breheny F. X. , Golledge C. L. , Cameron P. D. , Van Heerden P. V.
Published: January 2019

Epidemics of bacteraemia and wound infection have been associated with the infusion of bacterially contaminated propofol administered during anaesthesia. We conducted an observational study to determine the incidence and clinical significance of administration of potentially contaminated propofol to patients in an ICU setting. One hundred patients received a total of 302 infusions of propofol. Eighteen episodes of possible contamination of propofol syringes were identified, but in all cases contamination was by a low-grade virulence pathogen. There were no episodes of clinical infection or colonization which could be attributed to the administration of contaminated propofol. During the routine use of propofol to provide sedation in ICU patients the risk of nosocomial infection secondary to contamination of propofol is extremely low.
Comfort and Safety in Eye Surgery under Local Anaesthesia
Authors: Bosman Y. K. , Krige S. J. , Edge K. R. , Newstead J. , Dutoit P. W.
Published: January 2019

The study consisted of two parts:

1. The standard system in use at our hospital for gas delivery under the drapes during eye surgery under local anaesthesia was compared with one incorporating a venturi.

2. The oxygen concentration at the operation site was measured with three methods of draping using the two systems.

Twenty-three patients and thirty-one volunteers from the operating room staff were subjected to operating conditions and gas concentrations and certain vital signs measured using both systems. The subjective response of the volunteers, none of whom had blocks or premedication, was noted.

The burden of rebreathing seen with a significant proportion of cases using 6 l/min of fresh gas flow was not seen when the venturi system was used. The safety from fire hazard using 26% oxygen and diathermy was demonstrated with occlusive and free draping.
Anaesthesia Circuits, Humidity Output, and Mucociliary Structure and Function
Authors: Branson R. D. , Campbell R. S. , Davis K. , Porembka D. T.
Published: January 2019

We compared the effects of humidity delivered by the circle system at low fresh gas flows (FGF) with a conventional two-limb and coaxial circuit on the structure and function of the tracheobronchial epithelium in dogs. Animals were anaesthetized and mechanically ventilated using an anaesthesia ventilator to maintain normocarbia. Group I (control) animals received a FGF equal to the required minute ventilation mimicking an open circuit technique. Group II and III animals had FGF set at 20% of the required minute ventilation. Group II used a two-limb circuit and Group III used a coaxial circuit. Relative humidity and temperature of inspired gases were measured at baseline and hourly afterwards. In the first experiment, biopsies of the tracheobronchial tree were obtained bronchoscopically at baseline and then hourly for six hours. Microscopic examination of these samples allowed calculation of mean ciliary length. In the second experiment, tracheal mucus flow velocity (TMFV) was measured at baseline and hourly afterward, using a cinebroncho-fibrescopic method.

Delivered absolute humidity was greatest with low FGF and the coaxial circuit, followed by low FGF and a conventional circuit, and high FGF (15±1.4 vs 9±0.8 vs 5±0.4 mg H2O, P<0.01) after two hours. Mean cilia length (μ m) and TMFV (mm/min) fell during the first hour in all three groups. At hour two TMFV returned to baseline in Group III and was significantly greater than Groups I and II (0.8±0.4 vs 8.6±1.1 vs 15.4±2.1, P<0.001). Mean ciliary length demonstrated a similar pattern with reductions from baseline in all three groups for the first two hours. Groups II and III had an increase in cilia length beginning at hour three and were both significantly greater than Group I at hours 3 through 6 (1.3±0.5 vs 3.2±1.1 vs 4.2±0.8, P <0.001).

Alterations in tracheobronchial structure and function result from exposure to dry gases and are amplified by the duration of exposure. Our findings suggest a minimum of 12 to 15 mg H2O/l is necessary to prevent these alterations. In this study, the combination of low FGF and a coaxial anaesthesia circuit reached this minimum threshold more quickly than a conventional two-limb circuit.