JOURNAL WATCH MAY 2009
1 Modern rapidly degradable hydroxyethyl starches: current concepts. Anesth Analg. 2009 May;108(5):1574-82. Review.
It has been hard to miss the hype associated with Voluven marketing. Voluven is the third generation 130/0.4 hydroxyethyl starch (HES) colloid available in Australia. The author of this article states that specific funding from a pharmaceutical company did not support this review. However, the small print shows that Fresenius Kabi and B. Braun have supported him in the past, which are the companies responsible for most of the HES solutions available internationally. Remarkably, despite the persuasive undertone of the article in favour of HES colloids, it does not present a strong evidence base on which to base these recommendations. There is a striking absence of well-conducted studies and accurate data to support the use of the newer HES (lower MW & lower molar substitution than older preparations). The best evidence currently available appears to be based on a reduction in harm, rather than evidence of benefit. The newest generation HES solutions may have improved, but not completely resolved, the well documented adverse effects of older solutions including: coagulation defects, renal dysfunction, potential for allergy (as stated in the article: “no data on the incidence of anaphylactic reactions after IV administration of the last generation of HES are available”), accumulation & pruritus. Of note, voluven is presented in a saline-based rather than a balanced (plasma-like) solution recommended by some experts. The ‘safe’ dose and most appropriate clinical indications are yet to be determined. It becomes obvious that more questions than answers remain about the most appropriate fluid choices even without exploring all the alternative colloids available (gelatin/albumin/dextran-based) or the unresolved crystalloid vs colloid controversy (SAFE, Finfer, NEJM, 2004). It wasn’t that long ago that haemaccel was the colloid of choice…
Take home message: To achieve a rational perspective about new drugs or fluids, it is not adequate to rely on promotional material. Current evidence with regard to third generation HES, such as voluven, suggest that it appears to be safe but should be used with caution in some patient groups.
For related reading this month: Morgan TJ et al. Equivalent metabolic acidosis with four colloids and saline on ex vivo haemodilution. Anaesth Intensive Care. 2009 May;37(3):407-414.
2 Anaesthesia and right ventricular failure. Anaesth Intensive Care. 2009 May;37(3):370-85.
This paper presents an articulate account of the causes, pathophysiology and anaesthetic considerations relevant to right ventricular failure. Severe right ventricular dysfunction +/-pulmonary hypertension is obviously a daunting perioperative morbidity especially for the non-cardiac anaesthetist, which obviously makes this article a potentially valuable resource. The author relates the basic physiology of RVF to the clinical setting and provides a comprehensive review of the pharmacology that needs to be considered both from the anaesthetic perspective and for management of the challenging haemodynamics. Haemodynamic aims include maintenance of RV preload & contractility, avoidance of increases in PVR and decreases in MAP. The author emphasizes that the key haemodynamic signs of RV failure are an increased CVP and a decreased CO, and these parameters better reflect RV function than PAP. Likewise, RV dysfunction may be a more significant perioperative risk factor than the severity of PH and the key haemodynamic sign of a therapeutic response to inhaled pulmonary vasodilator therapy is not a reduction in PA pressures but a decrease in CVP and increase in CO. Significant increases in PVR may push the RV to the limit of the compensatory reserve & can be associated with profound RV decompensation, ischaemia and refractory cardiovascular collapse, especially if MAP is simultaneously reduced.
Take home message: RV dysfunction is a significant cause of mortality in patients with severe pulmonary hypertension undergoing non-cardiac surgery. Minimizing PVR and maintaining MAP are of central importance in the prevention of RV decompensation, which is characterized by a rising CVP & falling CO.
See also: February Journal Watch (7)
3 P6 acustimulation effectively decreases postoperative nausea and vomiting in high-risk patients. Br J Anaesth. 2009 May;102(5):620-5
Acustimulation of P6: an antiemetic alternative with no risk of drug-induced side-effects. Br J Anaesth. 2009 May;102(5):585-7 Editorial.
This prospective, observer-blind RCT investigated the efficacy of 24-continuous P6 acustimulation (n=101) or sham stimulation (n=99) in reducing PONV in a high-risk population. The P6 acupuncture point is on the flexor side of the wrist & acustimulation is electrical stimulation of acupuncture points. The study concluded that the incidence of PONV and need for rescue therapy was significantly lower in the intervention vs sham group: 33% vs 63% for PONV and that acustimulation provided a RR reduction of 50-60% if 3 or more Apfel risk factors were present (female, non-smoker, history of PONV/motion sickness, opioid analgesia). This is an impressive finding when one considers that the relative reduction of PONV with well-established drug treatments is approximately 25%. Of note the incidence of PONV in both groups was high and all patients had at least 2 risk factors, however the P6 acustimulation significantly reduced only nausea, not retching or vomiting, if patients had 3 or less risk factors. Study findings may be less generalizable because many anaesthetists would not use the study anaesthesia regimen with a population at high risk of PONV. The absence of PONV drug prophylaxis, use of N20/volatile gas mix, analgesic regimen consisting only of potent opioids and absence of multimodal analgesia or a regional technique (such as TAP blocks) are all factors that have been proven to contribute to PONV incidence, are modifiable and possibly even raises ethical questions about the conduct of the study. Limitations of this study include absence of a power analysis or discussion of methods for calculating sample size. The accompanying editorial (by Apfel) queries the subgroup analysis given the smallish sample size. It also emphasizes the common, but not always clinically relevant, side effects of conventional PONV drug treatments.
Take home message: The emerging evidence that P6 acustimulation may assist in reducing the incidence of PONV in high risk populations definitely seems worth pursuing given the virtual absence of side effects and few contraindications (i.e. implanted electrical devices.)
4 Reduction in intraoperative bacterial contamination of peripheral intravenous tubing through the use of a novel device. Anesthesiology. 2009 May;110(5):978-85. [Article]
Reducing perioperative infection is as simple as washing your hands. Anesthesiology. 2009 May;110(5):959-60 [Article]
This simple but elegant study reinforces the importance of basic interventions to improve outcomes (see also Safe Surgery Saves Lives, NEJM, Jan, 2009). Efficacy of hand hygiene was assessed via a controlled before and after study (n=114). The control group (n=58; blinded to study outcomes) was observed and hand hygiene decontamination (HHDEs) episodes recorded. The treatment group (n=53) was given a hand sanitation device that recorded each use and alarmed at 6-minute intervals to prompt hand hygiene. Data collected for both groups included bacterial cultures of 2 sites on the anaesthesia machine & the intravenous stopcock from each patient as well as surveillance of health-care associated infections (HCAIs) for 30 days postoperatively. The treatment group showed a 27-fold increase in hourly HHDEs. This was associated with statistically significant reductions in contamination of intravenous stopcocks (32% to 8%; OR 0.17) and HCAI (17% to 4%; OR 0.19). Intraoperative transmission of multidrug resistant organisms to intravenous stopcocks occurred in 3 cases in the control group and 2 of these 3 patients later died in ICU. In contrast, no multidrug resistant bacterial (0/53) were recovered in the stopcocks of the treatment group. Limitations include exclusion of 3 patients from final analysis and lack of randomization in the study design. However, as emphasized by the accompanying editorial, the results of this study are alarming and indicate that we need to recognize that anaesthetists maybe directly contributing to HCAI and unknowingly exposing our patients to harm. Instead of submitting to perceived inevitability of sub-optimal outcomes, we need to embrace the evidence that exists to change clinical practice. Lack of compliance with hand & workspace hygiene is potentially negligent at best. Increasing hand hygiene is certainly an easier undertaking than the widespread (? evidence-based) VRE protocols.
Take home message: Although a relatively unglamorous topic, simple improvements in the anaesthetic workspace and hand hygiene of anaesthetists has been demonstrated to markedly reduce intraoperative patient transmission of potentially pathogenic bacterial organisms which may ultimately reduce the burden of health-care associated infections.
For related reading this month: Neustein SM et al. Infection control practices by the anesthesiologist. Anesthesiology. 2009 May;110(5):1191; author reply 1191-2
5 Optimal perfusion during cardiopulmonary bypass: an evidence-based approach. Anesth Analg. 2009 May;108(5):1394-417. Review.
Cardiopulmonary bypass in 2009: achieving and circulating best practices. Anesth Analg. 2009 May;108(5):1368-70. Editorial:
The author of this coherent and comprehensive review has made an effort to summarize the evidence supporting or refuting the use of specific physiological goals during CPB with particular consideration given to the components of the bypass circuit. The discussion includes the science (or lack thereof) behind management of mean arterial blood pressure, oxygen delivery (pump flow, haematocrit values), temperature and acid-base strategy. In addition, the author attempts to make rational recommendations about circuit components including the blood pump, surface coating, oxygenator, reservoirs, cardiotomy suction & arterial line filters. Although there is mention of blood conservation strategies, the ongoing issue of optimal haemostatic therapies for bypass is not explored. This review adds to other published recommendations for bypass management: Shann, J Thorac & Cardiovasc Surgery, 2006; Hogue, A&A, 2006; Ferris, Ann Thorac Surg, 2007. The accompanying editorial commends the author on a ‘substantial and timely’ review and draws attention to the ongoing research commitment required in the quest to provide ’risk free CPB’.
Take home message: CPB remains a relatively high-risk undertaking, however there is a relative absence of definitive answers & consensus about the optimal management of bypass. Available evidence suggests that the physiological goals & targets should be individualized and considered on a case-by-case basis in response to the patient’s risk profile for adverse outcomes (i.e. CNS, POCD, renal, coagulation or other organ dysfunction).
For related reading this month: Billings FT et al. Transcatheter aortic valve implantation: anesthetic considerations. Anesth Analg. 2009 May;108(5):1453-62. Review. Hoover LR et al. Jugular venous oxygenation during hypothermic cardiopulmonary bypass in patients at risk for abnormal cerebral autoregulation: influence of alpha-Stat versus pH-stat blood gas management. Anesth Analg. 2009 May;108(5):1389-93. Couture P et al. Effects of anesthetic induction in patients with diastolic dysfunction. Can J Anaesth. 2009 May;56(5):357-365 Jakobsen CJ et al. High thoracic epidural analgesia improves left ventricular function in patients with ischemic heart. Acta Anaesthesiol Scand. 2009 May;53(5):559-64. Editorial Ricksten SE. Does thoracic epidural analgesia improve systolic and diastolic functions by improved myocardial oxygenation in patients with coronary artery disease? Acta Anaesthesiol Scand. 2009 May;53(5):556-8 Ranucci M et al. Living without aprotinin: the results of a 5-year blood saving program in cardiac surgery. Acta Anaesthesiol Scand. 2009 May;53(5):573-80
6 Reversal of profound neuromuscular block by sugammadex administered three minutes after rocuronium: a comparison with spontaneous recovery from succinylcholine. Anesthesiology. 2009 May;110(5):1020-5. [Article]
This is a drug company sponsored (Schering-Plough) RCT (n=110) comparing time to partial spontaneous recovery from a dose of suxamethonium (1 mg/kg) to reversal of rocuronium (1.2 mg/kg) with sugammadex (16 mg/kg). The study concluded that mean times to recovery of T1 to 10% and T1 to 90% after reversal of profound high-dose rocuronium induced neuromuscular block with sugammadex (4.4 and 6.2 mins respectively) was significantly faster than spontaneous recovery from suxamethonium (7.1 and 10.9 mins respectively). Perhaps more importantly, 87% of patients (47/54) showed T4/T1 TOF recovery to 0.9 6.1 mins after rocuronium-sugammadex administration. The discussion states that the timing of sugammadex administration, 3 mins after rocuronium was selected to imitate a real-life situation in which two attempts to intubate have failed and there is an unexpected requirement for immediate restoration of neuromuscular function. However, it is important to note that the endpoints reported (T1 10% & 90%) only measure partial neuromuscular recovery and could actually translate to differing levels of block, and potential for spontaneous respiratory effort, for deplolarising vs non-depolarising relaxants (minimal fade with suxamethonium.) The possible implications of this are unfortunately absent from the discussion so all we know is that the TOF 0.9 after sugammadex reversal (average 5.3 mins after roc), as reported above is likely to correspond to effective spontaneous ventilation but what would be the measured suxamethonium equivalent? It is also important to consider that, despite exclusions of most patients with organ dysfunction, there was a wide range of times to recovery after both sugammadex & suxamethonium reversal (maximum recovery times to T1 90% 13.6 & 16.2 mins respectively). Finally, 16 mg/kg would be a very expensive dose of sugammadex at current costings. Other selling points are going to be required (i.e. prevention of life-threatening suxamethonium related adverse effects, reduced incidence of postoperative residual curarisation (PORC) & PORC consequences, improvements to theatre efficiency, reliable rescue of CICV) to justify the cost of sugammadex especially when one considers the results of a recent systematic review ((Perry, Cochrane database, 2008) that concluded that suxamethonium creates excellent intubation conditions more reliably than rocuronium (including high dose) and should still be used as a first line muscle relaxant for RSI.
Take home message: This study shows that in most healthy patients, reversal of rocuronium (1.2 mg/kg) with sugammadex (16 mg/kg) can be achieved in approximately 6 mins to a level compatible with adequate spontaneous ventilation, presuming that other hypnotic agents are not preventing return of ventilation. Spontaneous recovery from a dose of suxamethonium is expected in approximately 10 mins in most healthy patients. This would only be a clinically relevant difference in the setting of a difficult airway if difficulties in ventilation were also encountered. However, available evidence does not suggest that either drug should be expected to reliably rescue a CICV situation (within the golden 5 minutes) in a predicted difficult airway when maintenance of spontaneous ventilation may be a safer option (significant range in reversal times even in the setting of a small sample).
See also: March Journal Watch (6); February Journal Watch (8)
7 Tattered threads. Anesth Analg. 2009 May;108(5):1361-3 Editorial
Perioperative analgesia: what do we still know? Anesth Analg. 2009 May;108(5):1364-7 Editorial.
Paired editorials in A and A examine the impact of the identification of fraudulent published research based on data fabricated by Dr. Scott Reuben. So far, twenty-one articles and abstracts spanning 15 years on investigation have been identified. Most relate to investigation of the role of NSAIDs, opioids, pregabalin and multimodal analgesic regimens as well as chronic pain research. The editorial by White attempts to summarise what remains established knowledge relating to perioperative analgesia and concludes that the benefits of COX-2 inhibitors is still evident in the acute setting but the ability of a multimodal preemptive regimen remains unproven as do novel routes of administration of NSAIDs and some other analgesics. The ultimate clinical effects of NSAIDs relating to bone fusion need further investigation and will be of great interest to our orthopaedic colleagues.
Take home message: The unprecedented withdrawal of 21 fraudulent articles from the anaesthetic literature, many of which suggested benefits with specific analgesic perioperative regimens will have significant impact on what was considered established knowledge, particularly relating to the efficacy of NSAIDs, including their potential adverse impact on bone healing.
8 When you need to know: the Obstetric Anaesthesia Scientific Evidence Project. Anaesth Intensive Care. 2009 May;37(3):351-3. Editorial
This editorial is intended to inform the Australasian anaesthesia community about a resource that the Obstetric Anaesthesia SIG has developed. It is a web-based resource that is accessed via the ANZCA website (ANZCA website-fellows-SIG-obstetric anaesthesia-scientific evidence guidelines) and aims to give an overview of the scientific evidence relevant to core obstetric topics. It is set up in a similar format to the Acute Pain Management Guidelines: Scientific Evidence. It is an evolving initiative and currently includes guidelines on the management of pre-eclampsia, regional analgesia for labour hypotension during LUSCS, aspiration prophylaxis & oral intake during labour.
Take home message: The recently developed scientific guidelines for obstetric anaesthesia available on the ANZCA website is likely to become a very useful resource, especially for the occasional obstetric anaesthetist.
For related reading this month: Gist RS et al. Amniotic fluid embolism. Anesth Analg. 2009 May;108(5):1599-602. Review.
9 Prediction of neurological outcome using bispectral index monitoring in patients with severe ischemic-hypoxic brain injury undergoing emergency surgery. Myles PS et al. Anesthesiology. 2009 May;110(5):1106-15.
Local investigators have used a prospective case-series (n=25) to examine the utility of BIS as a predictor of irreversible neurological injury in patients who suffered an ischaemic-hypoxic insult and required emergency surgery. Patients were deemed eligible for the study if they had suffered an acute arrest, major hypovolaemia or brain trauma and there was a subjective assessment from the anaesthetist involved that the patient had a high probability of severe irreversible brain injury. The study concluded that BIS more reliably indicated neurological outcome than either clinical judgment or pupillary responses (better sensitivity/specificity/PPV/NPV). An abnormal BIS (persistently low and /or EEG burst-suppression not explained by hypnotic drug administration) was associated with a 6.6 fold increased risk (CI 1.7-36.4) of poor neurological outcome and a normal BIS was associated with a fivefold increased probability of a good neurologic outcome. The incidence of poor neurological outcome (severe disability or death) was 68% (17/25). Overall, outcome (assessed by GCS) was predictably poor with 1 survivor severely disabled, 4 moderately disabled and 4 making a good recovery. Factors that may limit generalizability of the results of this study are the definition of a ‘normal BIS’. Both brain injury & anaesthetic drugs can lower BIS values so, in order for the anaesthetist to interpret an abnormal BIS, they must have adequate familiarity with BIS and expected response to hypnotic drugs to enable them to recognize abnormally low levels of BIS & unexpected burst suppression ratios. In addition, the author emphasizes that artifacts can result in a misleading BIS (hypothermia, EMG activity, electrical interference) and appraisal of the raw EEG is recommended. Furthermore, BIS was not designed as a monitor of brain injury so prognosis after serious hypoxic-ischaemic injury should not be determined solely on the information provided by BIS. Study power is limited by size of the study however this is always going be a challenge in this population given the requirement for surgery peri-arrest is a relatively rare event.
Take home message: In a patient who has suffered an acute neurological ischaemic-hypoxic insult, there is emerging evidence that ‘normal’ BIS parameters should encourage ongoing resuscitative effort. Also, in conjunction with established practices (neurologic evaluation, imaging), BIS may provide additional useful prognostic information in suspected irreversible brain injury.
10 Transfusion for trauma: civilian lessons from the battlefield? Anaesthesia. 2009 May;64(5):469-72 Editorial
This editorial discusses the rationale for the civilian adoption of a military-style massive transfusion protocol. Although the author acknowledges that circumstances and resources are different in the civilian setting, the specific coagulopathy of trauma is similar. Emphasis is placed on the fact that outcomes in survivable major trauma are determined very early and that the efforts should directed at stopping the bleeding rather than replacing the loss. The advantages of high ratio FFP:RBC transfusions are discussed as well as the emerging evidence for use of point of care coagulation testing such as thromoboelastography to direct therapy. For those interested in massive transfusion associated with trauma, the reference list includes some interesting recent papers.
Take home message: Evidence from massive transfusion in military trauma suggests that the most effective way to manage coagulopathy is early control of ongoing blood loss and administration of clotting factors in a similar ratio to red cells.
For related reading this month:
Tanaka KA et al. Blood coagulation: hemostasis and thrombin regulation. Anesth Analg. 2009 May;108(5):1433-46. Review. Mackman N. The role of tissue factor and factor VIIa in hemostasis. Anesth Analg. 2009 May;108(5):1447-52. Review. Gibbs NM. Point-of-care assessment of antiplatelet agents in the perioperative period: a review. Anaesth Intensive Care. 2009 May;37(3):354-369.
11 Postoperative neurocognitive dysfunction in elderly patients after xenon versus propofol anesthesia for major noncardiac surgery: a double-blinded randomized controlled pilot study. Anesthesiology. 2009 May;110(5):1068-76.
This small pilot RCT (n=101) attempted to explore the difference in incidence of POCD with propofol or xenon based anaesthesia for major non-cardiac surgery (>2 hrs). The incidence of POCD was remarkably high: Day 1, 6 and 30 was 44%/12%/6% and 50%/18%/12% for xenon & propofol respectively. The study was unable to demonstrate statistically significant differences in the substantial incidence of POCD between groups. However, the sample size calculation was based on the assumption that xenon would decrease the incidence of POCD by 2/3, which is obviously hopeful at best. Although many centers are currently researching POCD, conclusions are limited by the difficulties & lack of agreement in appropriate assessment of baseline cognitive function, the definition of POCD and the methods used to quantify it (neuropsychological testing). Notable features were the average age of patients was only 72 (65-83), there was no control group to assess test learning effect, 11% of original sample were lost to follow-up and all patients were premedicated with 0.07-0.1 mg/kg midazolam. It is possible that emphasizing only the agent used to achieve general anaesthesia is an oversimplification of the many insults encountered in the perioperative period (i.e. surgery, anaesthesia, pain, stress, haemodynamic instability, biochemical derangements and fluid shifts) and that other factors may be more important than the choice of anaesthetic agent i.e. perioperative haemodynamic goals or total sedative/analgesic doses, which were not reported in this study. Xenon does possess many attractive properties as an anaesthetic agent, including neuroprotection in animal studies, but it is very expensive and not available in Australia. Clearly, there is much work to be done in this area and it is impossible to draw definitive conclusions from this small pilot study (Type II error cannot be excluded).
Take home question: The incidence of POCD has been shown to be 26% at 1 week and 10% after 3 months (Moller, Lancet, 1998) and patients with POCD are at increased risk of death in the first year after surgery (Monk, Anesthesiology, 2008). Do you mention the incidence of POCD during informed consent for general anaesthesia to patients aged 60 yrs and older who are having major non-cardiac surgery? How many of the risks you do discuss routinely are as common as POCD in this age group?
For related reading this month: Baranov D et al. First International Workshop on Anesthetics and Alzheimer's Disease. Consensus statement: First International Workshop on Anesthetics and Alzheimer's disease. Anesth Analg. 2009 May;108(5):1627-30.
12 Perioperative beta-blockade: time to change the paradigm? Acta Anaesthesiol Scand. 2009 May;53(5):553-5. Editorial
This editorial attempts to give an unbiased perspective of the current role of perioperative beta blockade based on recent evidence including the POISE study (POISE study group, Lancet, 2008) and other recent evidence including a metaanalysis published in the Lancet (Bangalore, 2008) and contrasts this data to recommendations in the AHA guidelines (Fleisher, J Am Coll Cardiol, 2007). The discussion includes reference to the lower risk of MI but increased risk of mortality and CVA in the intervention (metoprolol) arm of the POISE study and the increased risk of predictable side effects of high-dose beta-blocker therapy: bradycardia & hypotension. The authors also mention the features of the POISE study design that limit the conclusions which can be drawn which include the high dose of metoprolol used (200 mg daily), the fact that beta blockade was only started immediately prior to surgery, continued for 30 days post-operatively and exclusion of the patient group that may benefit from beta-blockade the most, i.e. those patients who were already planned for perioperative beta-blocker therapy or taking beta blockers pre-operatively (obviously because of perceived benefits with the therapy.)
Take home message: It is not safe to assume that high-dose, routine beta-blockade taken for 30 days post-operatively is a safe intervention for every patient undergoing major non-cardiac surgery. However, there is evidence to suggest beta-blockade for a period of time may benefit subgroups of patients at risk of perioperative MI. A considered decision should be made on a case-by-case basis and, ideally, the response to therapy should be regularly reviewed and the dose should be titrated to pre-determined haemodynamic targets in a setting where there is adequate monitoring and resources to treat unfavourable haemodynamics if necessary.
13 Perioperative mortality risk score using pre- and postoperative risk factors in older patients. Story DA et al. Anaesth Intensive Care. 2009 May;37(3):392-398.
Local investigators have developed a risk score for post-operative mortality: the Perioperative Mortality risk score (POM). They used a derivation cohort from a previous study of patients aged >70 years (n=1012; McNicol, MJA, 2007) and then used a separate cohort (n=256) to validate the score. Overall mortality in both cohorts was 6%. The three preoperative factors and identified were: Age, ASA & Albumin and three postoperative factors: unplanned ICU, systemic Inflammation (considers temperature, WCC, RR, HR, positive blood culture) & acute renal Impairment. Scores and mortality were <5=1%, 5 to 9.5=7% and ≥10=26%. The C-statistic for the POM score (combining preoperative & postoperative elements) was 0.8, p<0.001 compared to 0.75, p<0.02 if only preoperative factors were included. This is comparable to previously developed risk scores (Aust, Ann Surg, 2005). The authors feel that the value of bedside risk scores include their ability in assisting in the informed consent process, determining if surgery is appropriate, planning critical care and giving patients and families progressive updates on likely prognosis. Limitations of the POM score include that it is only possible to calculate the full score day 5 post-operatively and is does not include consideration of surgical complexity and urgency. The study also underscores a fact that is sometimes difficult to fully appreciate as an anaesthetist: a successful surgical result requires patient survival for the perioperative period (i.e. at least 30 days), not just the operation.
Take home message: The perioperative mortality score, as developed by local investigators, may assist in bedside progressive risk assessment and management during the perioperative period.
Other articles of potential specific interest: Woodward LJ et al. Ankylosing spondylitis: recent developments and anaesthetic implications. Anaesthesia. 2009 May;64(5):540-8.
Fathi AR et al. Patent foramen ovale and neurosurgery in sitting position: a systematic review. Br J Anaesth. 2009 May;102(5):588-96 Koscielniak-Nielsen ZJ et al. A comparison of ultrasound-guided supraclavicular and infraclavicular blocks for upper extremity surgery. Acta Anaesthesiol Scand. 2009 May;53(5):620-6. Malik MA et al. Tracheal intubation in patients with cervical spine immobilization: a comparison of the Airwayscope, LMA CTrach, and the Macintosh laryngoscopes. Br J Anaesth. 2009 May;102(5):654-61 Thong SY et al. Evaluation of the airway in awake subjects with the McGrath® videolaryngoscope. Anaesth Intensive Care. 2009 May;37(3):497-503. Morris C et al. Anaesthesia in haemodynamically compromised emergency patients: does ketamine represent the best choice of induction agent? Anaesthesia. 2009 May;64(5):532-9. Subramaniam B et al. Continuous perioperative insulin infusion decreases major cardiovascular events in patients undergoing vascular surgery: a prospective, randomized trial. Anesthesiology. 2009 May; 110(5):970-7.
Disclaimers:
1 Best attempts are made to include articles representative of recent publications but no attempt is made to include every important article.
2 The commentary with take home message is only one of many possible opinions/interpretations of the literature.