The effect of sleep deprivation and disruption on DNA damage and health of doctors.

Observational studies have highlighted the detrimental health effects of shift work. The mechanisms through which acute sleep deprivation may lead to chronic disease have not been elucidated, but it is thought that increased DNA damage or decreased repair can lead to disease. The objective of this study was to examine the effects of acute sleep deprivation on DNA damage. This was a cross-sectional observational study on 49 healthy, full-time doctors. Baseline blood was sampled from each participant after three consecutive days of adequate sleep. Participants (n = 24) who were required to work overnight on-site had additional blood sampled on a morning after acute sleep deprivation. DNA damage and expression of DNA repair genes were quantified. Information on health, working patterns and sleep diaries were collected. Independent t-tests were used to compare differences between groups and standardised mean differences expressed as Cohen's d. Overnight on-site call participants had lower baseline DNA repair gene expression and more DNA breaks than participants who did not work overnight (d = 1.47, p = 0.0001; and 1.48, p = 0.0001, respectively). In overnight on-site call participants, after acute sleep deprivation, DNA repair gene expression was decreased (d = 0.90, p = 0.0001) and DNA breaks were increased (d = 0.87, p = 0.0018). Sleep deprivation in shift workers is associated with adverse health consequences. Increased DNA damage has been linked to the development of chronic disease. This study demonstrates that disrupted sleep is associated with DNA damage. Furthermore, larger prospective studies looking at relationships between DNA damage and chronic disease development are warranted, and methods to relieve, or repair, DNA damage linked to sleep deprivation should be investigated.

An international survey evaluating factors influencing the use of total intravenous anaesthesia.

The purpose of this study was to evaluate factors influencing the use of propofol-based total intravenous anaesthesia (TIVA)since despite TIVA being a well-established technique, it is used far less frequently than volatile anaesthesia. Questions were formulated after reviewing the literature for perceived disadvantages of TIVA and meeting with a focus group consisting of both senior and junior anaesthestists from our department. Once the survey had been formulated, specialist anaesthetists from professional colleges and societies from several countries were invited to complete the survey on an electronic web-based platform to allow evaluation of the respondent's rating of the importance of a range of factors in their decision not to use TIVA for a particular case. Basic descriptive statistics were determined using SPSS statistical software, while graphical depictions of data were handled using R for statistical analysis. A total of 763 survey responses were included in the final analysis and stratified according to the frequency of TIVA use. Among the infrequent users, issues such as additional effort, institutional preference, lack of real-time monitoring of propofol concentration, risk of missing drug delivery failure and increased turnaround time were among the top reasons mentioned. Interestingly, these issues were considered far less important among the frequent users when not choosing TIVA. We concluded that frequent and infrequent users respond quite differently to similar technical TIVA-related factors. Non-technical factors may play an important role in the infrequent user's decision not to use TIVA for a particular case.

The effect of remifentanil on propofol requirements to achieve loss of response to command vs. loss of response to pain.

When providing total intravenous anaesthesia, careful selection of end-points is required in titrating dose to effect during induction. Although propofol and remifentanil have predominantly different pharmacodynamic effects, they are seen to interact in achieving loss of consciousness and analgesia. To highlight these differences, we performed a double-blind, randomised controlled trial, comparing one group of patients receiving propofol alone (n = 42) with another group receiving remifentanil plus propofol (n = 46) as a target-controlled infusion of remifentanil (Minto; 3 ng.ml-1 ). Propofol was also titrated using a target-controlled infusion (Marsh effect model) to produce loss of response to tactile and vocal stimuli, and subsequently to loss of response to pain. The effect-site concentration of propofol at which 50% of patients lost tactile/verbal response was 2.9 µg.ml-1 in the propofol only group and 2.4 µg.ml-1 in the remifentanil with propofol group. In contrast, loss of pain response occurred at 4.4 µg.ml-1 in the propofol group, and 2.7 µg.ml-1 in the remifentanil with propofol group, with correspondingly lower bispectral index values. Judicious use of analgesia in total intravenous anaesthesia can have a propofol-sparing effect and potentially minimise the suppression of brain electrical activity. .

Contrast induced nephropathy in vascular surgery.

Contrast induced nephropathy (CIN) is traditionally associated with outpatient imaging studies. More recently, patients afflicted with vascular pathologies are increasingly undergoing endovascular treatments that require the use of iodinated contrast media (CM) agents, thus placing them as risk of developing CIN. As perioperative physicians, anaesthetists should be aware of the risk factors and measures that might minimize acute kidney injury caused by CM. This review evaluates recent data regarding preventive measures against CIN and where possible, places the evidence in the context of the patient receiving endovascular surgical treatment. Measures including the use of peri-procedural hydration, N-acetylcysteine, statins, remote ischaemic preconditioning, renal vasodilators and renal replacement therapy and the use of alternatives to iodinated contrast agents are discussed. It should be noted that most of the available data regarding CIN are from non-surgical patients.