Showing papers in "BJA: British Journal of Anaesthesia in 2010"

Effect of anaesthetic technique and other perioperative factors on cancer recurrence

Abstract: Surgical excision is the mainstay of treatment for potentially curable solid tumours. Metastatic disease is the most important cause of cancer-related death in these patients. The likelihood of tumour metastases depends on the balance between the metastatic potential of the tumour and the anti-metastatic host defences, of which cell-mediated immunity, and natural killer cell function in particular, is a critical component. It is increasingly recognized that anaesthetic technique and other perioperative factors have the potential to effect long-term outcome after cancer surgery. Surgery can inhibit important host defences and promote the development of metastases. Anaesthetic technique and drug choice can interact with the cellular immune system and effect long-term outcome. The potential effect of i.v. anaesthetics, volatile agents, local anaesthetic drugs, opiates, and non-steroidal anti-inflammatory drugs are reviewed here. There is particular interest at present in the effect of regional anaesthesia, which appears to be beneficial. Retrospective analyses have shown an outcome benefit for paravertebral analgesia for breast cancer surgery and epidural analgesia for prostatectomy. Blood transfusion, pain, stress, and hypothermia are other potentially important perioperative factors to consider.

When does acute pain become chronic

Abstract: The transition from acute to chronic pain appears to occur in discrete pathophysiological and histopathological steps. Stimuli initiating a nociceptive response vary, but receptors and endogenous defence mechanisms in the periphery interact in a similar manner regardless of the insult. Chemical, mechanical, and thermal receptors, along with leucocytes and macrophages, determine the intensity, location, and duration of noxious events. Noxious stimuli are transduced to the dorsal horn of the spinal cord, where amino acid and peptide transmitters activate second-order neurones. Spinal neurones then transmit signals to the brain. The resultant actions by the individual involve sensory-discriminative, motivational-affective, and modulatory processes in an attempt to limit or stop the painful process. Under normal conditions, noxious stimuli diminish as healing progresses and pain sensation lessens until minimal or no pain is detected. Persistent, intense pain, however, activates secondary mechanisms both at the periphery and within the central nervous system that cause allodynia, hyperalgesia, and hyperpathia that can diminish normal functioning. These changes begin in the periphery with upregulation of cyclo-oxygenase-2 and interleukin-1β-sensitizing first-order neurones, which eventually sensitize second-order spinal neurones by activating N-methyl-d-aspartic acid channels and signalling microglia to alter neuronal cytoarchitecture. Throughout these processes, prostaglandins, endocannabinoids, ion-specific channels, and scavenger cells all play a key role in the transformation of acute to chronic pain. A better understanding of the interplay among these substances will assist in the development of agents designed to ameliorate or reverse chronic pain.

Anaesthetists' non-technical skills

Abstract: This review presents the background to the development of the anaesthetists' non-technical skills (ANTS) taxonomy and behaviour rating tool, which is the first non-technical skills framework specifically designed for anaesthetists. We share the experience of the anaesthetists who designed ANTS in relation to applying it in a department of anaesthesia, using it in a simulation centre, and the process of introducing it to the profession on a national basis. We also consider how ANTS is being applied in relation to training and research in other countries and finally, we discuss emerging issues in relation to the introduction of a non-technical skills approach in anaesthesia.

Critical incident reporting and learning

Abstract: The success of incident reporting in improving safety, although obvious in aviation and other high-risk industries, is yet to be seen in health-care systems. An incident reporting system which would improve patient safety would allow front-end clinicians to have easy access for reporting an incident with an understanding that their report will be handled in a non-punitive manner, and that it will lead to enhanced learning regarding the causation of the incident and systemic changes which will prevent it from recurring. At present, significant problems remain with local and national incident reporting systems. These include fear of punitive action, poor safety culture in an organization, lack of understanding among clinicians about what should be reported, lack of awareness of how the reported incidents will be analysed, and how will the reports ultimately lead to changes which will improve patient safety. In particular, lack of systematic analysis of the reports and feedback directly to the clinicians are seen as major barriers to clinical engagement. In this review, robust systematic methodology of analysing incidents is discussed. This methodology is based on human factors model, and the learning paradigm which emphasizes significant shift from traditional judicial approach to understanding how 'latent errors' may play a role in a chain of events which can set up an 'active error' to occur. Feedback directly to the clinicians is extremely important for keeping them 'in the loop' for their continued engagement, and it should target different levels of analyses. In addition to high-level information on the types of incidents, the feedback should incorporate results of the analyses of active and latent factors. Finally, it should inform what actions, and at what level/stage, have been taken in response to the reported incidents. For this, local and national systems will be required to work in close cooperation, so that the lessons can be learnt and actions taken within an organization, and across organizations. In the UK, a recently introduced speciality-specific incident reporting system for anaesthesia aims to incorporate the elements of successful reporting system, as presented in this review, to achieve enhanced clinical engagement and improved patient safety.

Efficacy and safety of paravertebral blocks in breast surgery: a meta-analysis of randomized controlled trials

Abstract: Background Thoracic paravertebral blocks (PVBs) are successfully performed for pain management after breast surgery. The aim of the present quantitative systematic review was to assess the efficacy and adverse events of PVB in women undergoing breast surgery. Methods The systematic search, data extraction, critical appraisal, and pooled analysis were performed according to the PRISMA statement. The relative risk (RR), mean difference (MD), and their corresponding 95% confidence intervals (CIs) were calculated using the RevMan® statistical software for dichotomous and continuous outcomes, respectively. Pain scores were converted to a scale ranging from 0 (no pain) to 10 (worst pain). Results Fifteen randomized controlled trials (published between 1999 and 2009) including 877 patients met the inclusion criteria. There was a significant difference in worst postoperative pain scores between PVB and general anaesthesia (GA) at Conclusions There is considerable evidence that PVB in addition to GA or alone provide a better postoperative pain control with little adverse effects compared with other analgesic treatment strategies.

Impaired functional capacity is associated with all-cause mortality after major elective intra-abdominal surgery

Abstract: capacity. † Ischaemic heart disease is the only clinical indicator associated with mortality after major surgery. † Patients with no cardiac risk factors are equally at risk from impaired functional capacity. Background. Studies of preoperative cardiopulmonary exercise testing (CPET) have shown that a reduced oxygen uptake at anaerobic threshold (AT) and elevated ventilatory equivalent for carbon dioxide (VE/VCO2) were associated with reduced short- and medium-term survival after major surgery. The aim of this study was to determine the relative values of these, and also clinical risk factors, in identifying patients at risk of death after major intra-abdominal, non-vascular surgery.

Early childhood general anaesthesia exposure and neurocognitive development

Abstract: Summary A great deal of concern has recently arisen regarding the safety of anaesthesia in infants and children. There is mounting and convincing preclinical evidence in rodents and non-human primates that anaesthetics in common clinical use are neurotoxic to the developing brain in vitro and cause long-term neurobehavioural abnormalities in vivo . An estimated 6 million children (including 1.5 million infants) undergo surgery and anaesthesia each year in the USA alone, so the clinical relevance of anaesthetic neurotoxicity is an urgent matter of public health. Clinical studies that have been conducted on the long-term neurodevelopmental effects of anaesthetic agents in infants and children are retrospective analyses of existing data. Two large-scale clinical studies are currently underway to further address this issue. The PANDA study is a large-scale, multisite, ambi-directional sibling-matched cohort study in the USA. The aim of this study is to examine the neurodevelopmental effects of exposure to general anaesthesia during inguinal hernia surgery before 36 months of age. Another large-scale study is the GAS study, which will compare the neurodevelopmental outcome between two anaesthetic techniques, general sevoflurane anaesthesia and regional anaesthesia, in infants undergoing inguinal hernia repair. These study results should contribute significant information related to anaesthetic neurotoxicity in children.

To continue or discontinue aspirin in the perioperative period: a randomized, controlled clinical trial

Abstract: Background: Major adverse cardiac events (MACEs) are a common cause of deathafter non-cardiac surgery. Despite evidence for the benefitof aspirin for secondary prevention, it is often discontinuedi ...

Pharmacological prevention of sevoflurane- and desflurane-related emergence agitation in children: a meta-analysis of published studies

Abstract: the pooled odds ratio (OR) and 95% confidence interval. I 2 statistics were used to assess statistics heterogeneity and the funnel plot and the Begg‐Mazumdar test to assess bias. Results. Thirty-seven articles were found which included a total of 1695 patients in the intervention groups and 1477 in the control ones. Midazolam and 5HT3 inhibitors were not found to have a protective effect against EA [OR¼0.88 (0.44, 1.76); OR¼0.39 (0.12, 1.31), respectively], whereas propofol [OR¼0.21 (0.16, 0.28)], ketamine [OR¼0.28 (0.13, 0.60)], a2adrenoceptors [OR¼0.23 (0.17, 0.33)], fentanyl [OR¼0.31 (0.18, 0.56)], and peroperative analgesia [OR¼0.15 (0.07, 0.34)] were all found to have a preventive effect. Subgroup analysis according to the peroperative analgesia given does not affect the results. Conclusions. This meta-analysis found that propofol, ketamine, fentanyl, and preoperative analgesia had a prophylactic effect in preventing EA. The analgesic properties of these drugs do not seem to have a role in this effect. Br J Anaesth 2010; 104: 216‐23

Complications of peripheral nerve blocks

Abstract: Summary Complications of peripheral nerve blocks are fortunately rare, but can be devastating for both the patient and the anaesthesiologist. This review will concentrate on current knowledge about peripheral nerve injury secondary to nerve blocks, complications from continuous peripheral nerve catheter techniques, and local anaesthetic systemic toxicity.

Dose adjustment of anaesthetics in the morbidly obese

Abstract: Anaesthesiologists must be prepared to deal with pharmacokinetic and pharmacodynamic (PD) differences in morbidly obese individuals. As drug administration based on total body weight can result in overdose, weight-based dosing scalars must be considered. Conversely, administration of drugs based on ideal body weight can result in a sub-therapeutic dose. Changes in cardiac output and alterations in body composition affect the distribution of numerous anaesthetic drugs. With the exception of neuromuscular antagonists, lean body weight is the optimal dosing scalar for most drugs used in anaesthesia including opioids and anaesthetic induction agents. The increased incidence of obstructive sleep apnoea and fat deposition in the pharynx and chest wall places the morbidly obese at increased risk for adverse respiratory events secondary to anaesthetic agents, thus altering the PD properties of these drugs. Awareness of the pharmacology of the commonly used anaesthetic agents including induction agents, opioids, inhalation agents and neuromuscular blockers is necessary for safe and effective care of morbidly obese patients.

Effect of preoperative multimedia information on perioperative anxiety in patients undergoing procedures under regional anaesthesia

Abstract: Background Provision of preoperative information can alleviate patients' anxiety. However, the ideal method of delivering this information is unknown. Video information has been shown to reduce patients' anxiety, although little is known regarding the effect of preoperative multimedia information on anxiety in patients undergoing regional anaesthesia. Methods We randomized 110 patients undergoing upper or lower limb surgery under regional anaesthesia into the study and control groups. The study group watched a short film (created by the authors) depicting the patient's in-hospital journey including either a spinal anaesthetic or a brachial plexus block. Patients' anxiety was assessed before and after the film and 1 h before and within 8 h after their operation, using the Spielberger state trait anxiety inventory and a visual analogue scale. Results There was no difference in state and trait anxiety between the two groups at enrolment. Women had higher baseline state and trait anxiety than men (P=0.02). Patients in the control group experienced an increase in state anxiety immediately before surgery (P Conclusions Preoperative multimedia information reduces the anxiety of patients undergoing surgery under regional anaesthesia. This type of information is easily delivered and can benefit many patients.

Cell salvage as part of a blood conservation strategy in anaesthesia

Abstract: Summary The use of intraoperative cell salvage and autologous blood transfusion has become an important method of blood conservation. The main aim of autologous transfusion is to reduce the need for allogeneic blood transfusion and its associated complications. Allogeneic blood transfusion has been associated with increased risk of tumour recurrence, postoperative infection, acute lung injury, perioperative myocardial infarction, postoperative low-output cardiac failure, and increased mortality. We have reviewed the current evidence for cell salvage in modern surgical practice and examined the controversial issues, such as the use of cell salvage in obstetrics, and in patients with malignancy, or intra-abdominal or systemic sepsis. Cell salvage has been demonstrated to be safe and effective at reducing allogeneic blood transfusion requirements in adult elective surgery, with stronger evidence in cardiac and orthopaedic surgery. Prolonged use of cell salvage with large-volume autotransfusion may be associated with dilution of clotting factors and thrombocytopenia, and regular laboratory or near-patient monitoring is required, along with appropriate blood product use. Cell salvage should be considered in all cases where significant blood loss (>1000 ml) is expected or possible, where patients refuse allogeneic blood products or they are anaemic. The use of cell salvage in combination with a leucocyte depletion filter appears to be safe in obstetrics and cases of malignancy; however, further trials are required before definitive guidance may be provided. The only absolute contraindication to the use of cell salvage and autologous blood transfusion is patient refusal.

Analgesia and functional outcome after total knee arthroplasty: periarticular infiltration vs continuous femoral nerve block

Abstract: Background Capacity to ambulate represents an important milestone in the recovery process after total knee arthroplasty (TKA). The purpose of this study was to determine the analgesic effect of two analgesic techniques and their impact on functional walking capacity as a measure of surgical recovery. Methods Forty ASA II–III subjects undergoing TKA were enrolled in a randomized, double-blind, single-centre study receiving 48 h postoperative analgesia with either periarticular infiltration of local anaesthetic (Group I) or continuous femoral nerve block (Group F). Breakthrough pain relief was achieved with patient-controlled analgesia (PCA) morphine. The main outcome was postoperative morphine consumption. Early (postoperative days 1–3) and late (6 weeks) functional walking capacity (2 and 6 min walk tests, 2MWT and 6MWT, respectively), degree of physical activity (CHAMPS), health-related quality of life (SF-12), and clinical indicators of knee function (WOMAC, Knee Society evaluation, and range of motion) were measured. Results Patients in Group F used the PCA less ( P =0.02) to achieve adequate analgesia. Postoperative 2MWT was similar in both groups ( P =0.27). Six weeks after surgery, recovery of 6MWT, physical activity, and knee function were significantly improved in Group F ( P Conclusions Femoral block is associated with lower opioid consumption and a better recovery at 6 weeks than periarticular infiltration. Early postoperative activity measures (2MWT and walking time) were proved to be possible indicators of knee function recovery at 6 weeks after surgery.

Role of fibrinogen in trauma-induced coagulopathy

Abstract: Coagulation defects related to severe trauma, trauma-induced coagulopathy (TIC), have a number of causal factors including: major blood loss with consumption of clotting factors and platelets, and dilutional coagulopathy after administration of crystalloids and colloids to maintain blood pressure. In addition, activation of the fibrinolytic system or hyperfibrinolysis, hypothermia, acidosis, and metabolic changes can also affect the coagulation system. All of these directly affect fibrinogen polymerization and metabolism. Other bleeding-related deficiencies usually develop later in massive bleeding related to severe multiple trauma. In major blood loss, fibrinogen reaches a critical value earlier than other procoagulatory factors, or platelets. The question of the critical threshold value is presently the subject of heated debate. A threshold of 100 mg dl(-1) has been recommended, but recent clinical data have shown that at a fibrinogen level of <150-200 mg dl(-1), there is already an increased tendency to peri- and postoperative bleeding. A high fibrinogen count exerts a protective effect with regard to the amount of blood loss. In multiple trauma patients, priority must be given to early and effective correction of impaired fibrin polymerization by administering fibrinogen concentrate.

Sepsis and the heart

Abstract: Septic shock, the most severe complication of sepsis, accounts for ∼10% of all admissions to intensive care. Our understanding of its complex pathophysiology remains incomplete but clearly involves stimulation of the immune system with subsequent inflammation and microvascular dysfunction. Cardiovascular dysfunction is pronounced and characterized by elements of hypovolaemic, cytotoxic, and distributive shock. In addition, significant myocardial depression is commonly observed. This septic cardiomyopathy is characterized by biventricular impairment of intrinsic myocardial contractility, with a subsequent reduction in left ventricular (LV) ejection fraction and LV stroke work index. This review details the myocardial dysfunction observed in adult septic shock, and discusses the underlying pathophysiology. The utility of using the regulatory protein troponin for the detection of myocardial dysfunction is also considered. Finally, options for the management of sepsis-induced LV hypokinesia are discussed, including the use of levosimendan.

Influence of steep Trendelenburg position and CO(2) pneumoperitoneum on cardiovascular, cerebrovascular, and respiratory homeostasis during robotic prostatectomy.

Abstract: Background The steep (40°) Trendelenburg position optimizes surgical exposure during robotic prostatectomy. The goal of the current study was to investigate the combined effect of this position and CO2 pneumoperitoneum on cardiovascular, cerebrovascular, and respiratory homeostasis during these procedures. Methods Physiological data were recorded during the whole surgical procedure in 31 consecutive patients who underwent robotic endoscopic radical prostatectomy under general anaesthesia. Heart rate, mean arterial pressure, central venous pressure, Spo2, Pe′co2, PPlat, tidal volume, compliance, and minute ventilation were monitored and recorded. Arterial samples were obtained to determine the arterial-to-end-tidal CO2 tension gradient. Continuous regional cerebral tissue oxygen saturation (Scto2) was determined by near-infrared spectroscopy. Results Although patients were in the Trendelenburg position, all variables investigated remained within a clinically acceptable range. Cerebral perfusion pressure (CPP) decreased from 77 mm Hg at baseline to 71 mm Hg (P=0.07), and Scto2 increased from 70% to 73% (P Conclusions The combination of the prolonged steep Trendelenburg position and CO2 pneumoperitoneum was well tolerated. Haemodynamic and pulmonary variables remained within safe limits. Regional cerebral oxygenation was well preserved and CPP remained within the limits between which cerebral blood flow is usually considered to be maintained by cerebral autoregulation.

Urgent surgery in patients with a recently implanted coronary drug-eluting stent: a phase II study of ‘bridging’ antiplatelet therapy with tirofiban during temporary withdrawal of clopidogrel

Abstract: Background Patients with a recently implanted coronary drug-eluting stent (DES) who need urgent surgery are at increased risk of surgical bleeding unless clopidogrel is discontinued beforehand, but clopidogrel discontinuation has been associated with a high rate of adverse events due to stent thrombosis. This pilot study tested the hypothesis that the i.v. perioperative administration of the short-acting antiplatelet agent tirofiban allows the safe withdrawal of clopidogrel without increasing the rate of surgical bleeding. Methods Phase II study with a Simon two-stage design. Results Thirty patients with a recently implanted DES [median (range) 4 (1–12) months] and high-risk characteristics for stent thrombosis underwent urgent major surgery or eye surgery. Clopidogrel was to be withdrawn 5 days before surgery, and tirofiban started 24 h later, continued until 4 h before surgery, and resumed 2 h after surgery until oral clopidogrel was resumed. The use of aspirin was decided by the surgeon. There were no cases of death, myocardial infarction, stent thrombosis, or surgical re-exploration due to bleeding during the index admission, with a risk estimate of 0–11.6% (one-tail 97.5% CI). There was one case of thrombolysis in myocardial infarction (TIMI) major and one of TIMI minor bleeding in the postoperative phase; another four patients were transfused without meeting the TIMI criteria for major or minor bleeding. Conclusions In patients with a recently implanted DES and high-risk characteristics for stent thrombosis needing urgent surgery, a ‘bridging strategy' using i.v. tirofiban may allow temporary withdrawal of oral clopidogrel without increasing the risk of bleeding.

Fifteen years of ultrasound guidance in regional anaesthesia: Part 1

Abstract: Ultrasound guidance for regional anaesthesia has gained enormous popularity in the past decade. The use of ultrasound guidance for many regional anaesthetic techniques is common in daily clinical practice, and the number of practitioners using it is increasing. However, alongside the enthusiasm, there should be a degree of informed scepticism. The widespread use of the various techniques of ultrasound-guided regional blocks without adequate training raises the danger of malpractice and subsequent impaired outcome. Adequate education in the use of regional block techniques under ultrasound guidance is essential. This review article addresses ultrasound guidance for regional anaesthesia, and is divided into two parts because of the size of the topic and the number of issues covered. This first part includes a review and preview of ultrasound guidance in regional anaesthesia and discusses all aspects of ultrasound for regional anaesthesia with a focus on recent technical developments, the positive implications in economics, further potential advantages (e.g. detection of anatomical variants, painless performance of blocks) and education. It also attempts to define a ‘gold standard' in regional anaesthesia with the most recent findings in adequate volumes of local anaesthetics for peripheral nerve blocks. This standard should include an extraneural needle position, a high success rate, and wide application of ultrasound guidance in regional anaesthesia. The second part describes the impact of ultrasound on the development of nerve block techniques in the past 5 yr.

Tranexamic acid in hip fracture surgery: a randomized controlled trial

Abstract: Background Hip fracture surgery may be associated with substantial blood loss. This study was designed to assess the efficacy and safety of the use of tranexamic acid in hip fracture surgery for the reduction of erythrocyte transfusion. Methods The study pertains to a randomized double-blind study with blinded adjudication of outcomes. Patients requiring surgery for an isolated hip fracture of less than 48 h received saline or tranexamic acid 15 mg kg−1 given at skin incision and 3 h later. Primary efficacy outcome was erythrocyte transfusion from surgery up to day 8. Transfusion was administered according to a standardized protocol (Hb Results Fifty-seven patients were randomized to tranexamic acid and 53 to placebo. The rate of erythrocyte transfusion was 42% with tranexamic acid and 60% with placebo (P=0.06). Preoperative haemoglobin value, age, and type of surgery were risk factors for erythrocyte transfusion independent of treatment group. The probability of vascular events at 6 weeks was 16% in the tranexamic acid group and 6% in the placebo group (P=0.10). A meta-analysis combining this study with previous trials showed that tranexamic acid significantly reduced erythrocyte transfusion in hip fracture surgery although efficacy was lower than that observed in hip or knee arthroplasty. Conclusions In hip fracture surgery, tranexamic acid reduces erythrocyte transfusion but may promote a hypercoagulable state. Thus, further evaluation of safety is required before recommending the off-label use of tranexamic acid.

Recovery of fibrinogen after administration of fibrinogen concentrate to patients with severe bleeding after cardiopulmonary bypass surgery

Abstract: Background. Normalization of plasma fibrinogen levels may be associated with satisfactory haemostasis and reduced bleeding. The aim of this retrospective study was to assess fibrinogen recovery parameters after administration of fibrinogen concentrate (Haemocomplettan w P) to patients with diffuse bleeding in cardiovascular surgery. Data on transfusion and patient outcomes were also collected. Methods. Patient characteristic and clinical data were obtained from patient records. Results of the thromboelastometry (FIBTEM w ) and of the standard coagulation tests, including plasma fibrinogen level, measured before surgery, before and after haemostatic therapy, and on the following day, were retrieved from laboratory records. Results. Thirty-nine patients receiving fibrinogen concentrate for diffuse bleeding requiring haemostatic therapy after cardiopulmonary bypass were identified. The mean fibrinogen concentrate dose administered was 6.5 g. The mean fibrinogen level increased from 1.9 to 3.6 g litre 21 (mean increment of 0.28 g litre 21 per gram of concentrate administered); maximum clot firmness increased from 10 to 21 mm. The mean fibrinogen increase was 2.29 (SD 0.7) mg dl 21 per mg kg 21 bodyweight of concentrate administered. Thirty-five patients received no transfusion of fresh-frozen plasma (FFP) or platelet concentrate after receiving fibrinogen concentrate; the remaining four patients received platelet concentrate intraoperatively. Eleven patients received platelets, FFP, or both during the first postoperative day. No venous thromboses, arterial ischaemic events, or deaths were registered during hospitalization. Conclusions. In this retrospective study, fibrinogen concentrate was effective in increasing plasma fibrinogen level, and contributed to the correction of bleeding after cardiovascular surgery. Br J Anaesth 2010; 104: 555‐62

Postoperative residual curarization from intermediate-acting neuromuscular blocking agents delays recovery room discharge

Abstract: Background Postoperative residual curarization (PORC) [train-of-four ratio (T4/T1) Methods At admission to the PACU, neuromuscular transmission was assessed by acceleromyography (stimulation current: 30 mA) in 246 consecutive patients. The potential consequences of PORC-induced increases in PACU length of stay on PACU throughput were estimated by application of a validated queuing model taking into account the rate of PACU admissions and mean length of stay in the joint system of the PACU plus patients recovering in operation theatre waiting for PACU beds. Results PACU length of stay was significantly longer in patients with T4/T1 Conclusions PORC is associated with a delayed PACU discharge. The magnitude of the effect is clinically significant. In our system, PORC increases the chances of patients having to wait to enter the PACU.

Adding ketamine to morphine for intravenous patient-controlled analgesia for acute postoperative pain: a qualitative review of randomized trials

Abstract: In experimental trials, ketamine has been shown to reduce hyperalgesia, prevent opioid tolerance, and lower morphine consumption. Clinical trials have found contradictory results. We performed a review of randomized, double-blinded clinical trials of ketamine added to opioid in i.v. patient-controlled analgesia (PCA) for postoperative pain in order to clarify this controversy. Our primary aim was to compare the effectiveness and safety of postoperative administered ketamine in addition to opioid for i.v. PCA compared with i.v. PCA with opioid alone. Studies were identified from the Cochrane Library 2003, MEDLINE (1966-2009), and EMBASE (1980-2009) and by hand-searching reference lists from review articles and trials. Eleven studies were identified with a total of 887 patients. Quality and validity assessment was performed on all trials included using the Oxford Quality Scale with an average quality score of 4.5. Pain was assessed using visual analogue scales or verbal rating scales. Six studies showed significant improved postoperative analgesia with the addition of ketamine to opioids. Five studies showed no significant clinical improvement. For thoracic surgery, the addition of ketamine to opioid for i.v. PCA was superior to i.v. PCA opioid alone. The combination allows a significant reduction in pain score, cumulative morphine consumption, and postoperative desaturation. The benefit of adding ketamine to morphine in i.v. PCA for orthopaedic or abdominal surgery remains unclear. Owing to huge heterogeneity of studies and small sample sizes, larger double-blinded randomized studies showing greater degree of homogeneity are required to confirm these findings.

Recognizing and managing a malignant hyperthermia crisis: guidelines from the European Malignant Hyperthermia Group

Abstract: Survival from a malignant hyperthermia (MH) crisis is highly dependent on early recognition and prompt action. MH crises are very rare and an increasing use of total i.v. anaesthesia is likely to make it even rarer, leading to the potential risk of reduced awareness of MH. In addition, dantrolene, the cornerstone of successful MH treatment, is unavailable in large areas around the world thereby increasing the risk of MH fatalities in these areas. The European Malignant Hyperthermia Group collected and reviewed all guidelines available from the various MH centres in order to provide a consensus document. The guidelines consist of two textboxes: Box 1 on recognizing MH and Box 2 on the treatment of an MH crisis.

Use of albumin: an update

Abstract: Human albumin (HA) is widely used for volume replacement or correction of hypoalbuminaemia. The value of HA in the clinical setting continues to be controversial, and it is unclear whether in today's climate of cost consciousness, there is still a place for such a highly priced substance. It is therefore appropriate to update our knowledge of the value of HA. With the exception of women in early pregnancy, there appears to be few indications for the use of HA to correct hypovolaemia. Some studies of traumatic brain injury and intensive care patients suggest negative effects on outcome and organ function of (hyperoncotic) HA. Modern synthetic colloids appear to be a cheaper alternative for maintaining colloid oncotic pressure. The value of using HA to correct hypoalbuminaemia has not been clearly justified. Theoretical and pharmacological benefits of HA, such as oxygen radical scavenging or binding of toxic substances, have not as yet been shown to have beneficial clinical consequences. Experimental data from cell lines or animals do not appear to mimic the clinical setting. Convincing data justifying the use of HA either for treating hypovolaemia or for correcting hypoalbuminaemia are still lacking. A restricted use of HA is recommended.

Labour analgesia and obstetric outcomes

Abstract: Summary Neuraxial analgesic techniques are the gold standards for pain relief during labour and delivery. Despite the increased use and known benefits of neuraxial labour analgesia, there has been significant controversy regarding the impact of neuraxial analgesia on labour outcomes. Review of the evidence suggests that effective neuraxial labour analgesia does not increase the rate of Caesarean delivery, even when administered early in the course of labour; however, its use is associated with a prolonged second stage of labour. Effective second-stage analgesia might also be associated with an increased rate of instrumental vaginal delivery.

Beyond monitoring: distributed situation awareness in anaesthesia

Abstract: Situation awareness (SA) is one of the essential non-technical skills for effective and safe practice in high-risk industries, such as healthcare; yet, there is limited research of its significance in anaesthetic practice. In this paper, we review this scant research that focuses on SA as patient monitoring alone and advocate for a more comprehensive view of SA in anaesthetic practice and training that extends beyond monitoring, namely, a distributed cognition approach. We identify further factors influencing anaesthetists' SA and provide a case that resulted in an anaesthetic fatality to illustrate the application of an alternative view of SA in anaesthesia. Distributed SA in anaesthetic practice provides the foundation for further research that may in turn influence the teaching and assessment of this important non-technical skill.

Influence of obesity on propofol pharmacokinetics: derivation of a pharmacokinetic model

Abstract: Background The objective of this study was to develop a pharmacokinetic (PK) model to characterize the influence of obesity on propofol PK parameters. Methods Nineteen obese ASA II patients undergoing bariatric surgery were studied. Patients received propofol 2 mg kg−1 bolus dose followed by a 5–20–40–120 min, 10–8–6–5 mg kg−1 h−1 infusion. Arterial blood samples were withdrawn at 1, 3, 5 min after induction, every 10–20 min during propofol infusion, and every 10–30 min for 2 h after stopping the propofol infusion. Arterial samples were processed by high-performance liquid chromatography. Time–concentration data profiles from this study were pooled with data from two other propofol PK studies available at http://www.opentci.org. Population PK modelling was performed using non-linear mixed effects model. Results The study involved 19 obese adults who contributed 163 observations. The pooled analysis involved 51 patients (weight 93 sd 24 kg, range 44–160 kg; age 46 sd 16 yr, range 25–81 yr; BMI 33 sd 9 kg m−2, range 16–52 kg m−2). A three-compartment model was used to investigate propofol PK. An allometric size model using total body weight (TBW) was superior to all other models investigated (linear TBW, free fat mass, lean body weight, normal fat mass) for all clearance parameters. Variability in V2 and Q2 was reduced by a function showing a decrease in both parameters with age. Conclusions We have derived a population PK model using obese and non-obese data to characterize propofol PK over a wide range of body weights. An allometric model using TBW as the size descriptor of volumes and clearances was superior to other size descriptors to characterize propofol PK in obese patients.