A review of ASA physical status - historical perspectives and modern developments.

The American Society of Anesthesiologists (ASA) physical status is a tool commonly used to classify a patient's physical fitness before surgery. Since its introduction in 1941 it has undergone very few modifications to improve its reliability and to eliminate subjectivity, despite vast changes in both surgical and anaesthetic technique. We present the history of the ASA physical status and review the literature on its applicability to contemporary anaesthetic practice.

Implications of deranged activated partial thromboplastin time for anaesthesia and surgery.

Bleeding during and after surgery ranges from trivial to fatal. Bleeding is in part determined by the patient's coagulation status. The UK National Institute for Health and Care Excellence recommends a pre-operative clotting test for patients with a history of abnormal bleeding. Anaesthetists are familiar with the prothrombin time assay, used to monitor warfarin effect, but anaesthetists may be less familiar with the activated partial thromboplastin time (APTT), which tests the function of the 'intrinsic' clotting pathway. The activated partial thromboplastin time may be prolonged due to contamination, anticoagulant therapy, clotting factor deficiencies, lupus anticoagulant or acquired inhibitors of specific clotting factors. A prolonged activated partial thromboplastin time should lead to: further testing to exclude heparin contamination or therapy, mixing studies to identify factor deficiencies and if necessary dynamic studies, such as the dilute Russell's viper venom time and the Actin FS-activated partial thromboplastin time, to identify direct factor inhibitors. These tests identify abnormalities and their implications for bleeding, helping anaesthetists and haematologists to manage haemostasis for individual patients.

Zirconia toughened mica glass ceramics for dental restorations.

OBJECTIVE: The objective of the present study is to understand the role of yttria stabilized zirconia (YSZ) in achieving the desired spectrum of clinically relevant mechanical properties (hardness, elastic modulus, fracture toughness and brittleness index) and chemical solubility of mica glass ceramics. METHODS: The glass-zirconia mixtures with varying amounts of YSZ (0, 5, 10, 15 and 20wt.%) were ball milled, compacted and sintered to obtain pellets of glass ceramic-YSZ composites. Phase analysis was carried out using X-ray diffraction and microstructural characterization with SEM revealed the crystal morphology of the composites. Mechanical properties such as Vickers hardness, elastic modulus, indentation fracture toughness and chemical solubility were assessed. RESULTS: Phase analysis of sintered pellets of glass ceramic-YSZ composites revealed the characteristic peaks of fluorophlogopite (FPP) and tetragonal zirconia. Microstructural investigation showed plate and lath-like interlocking mica crystals with embedded zirconia. Vickers hardness of 9.2GPa, elastic modulus of 125GPa, indentation toughness of 3.6MPa·m1/2, and chemical solubility of 30µg/cm2 (well below the permissible limit) were recorded with mica glass ceramics containing 20wt.% YSZ. SIGNIFICANCE: An increase in hardness and toughness of the glass ceramic-YSZ composites with no compromise on their brittleness index and chemical solubility has been observed. Such spectrum of properties can be utilised for developing a machinable ceramic for low stress bearing inlays, onlays and veneers.

Cerebroprotective potential of resveratrol through anti-oxidant and anti-inflammatory mechanisms in rats.

Oxidative stress and inflammation are two important pathological mechanisms involved in cerebral ischemia and reperfusion injury. In pathological conditions such as cerebral infarction, the free radical production is greater than that of elimination by endogenous anti-oxidant system, by this undesirable effect brain is highly injured. Resveratrol is reported to have anti-oxidant and anti-inflammatory, athero-protective activities. Therefore, the aim of the present study is to evaluate the therapeutic potential of resveratrol against cerebral infarction induced by ischemia and reperfusion injury in Wistar rats. Bi-common carotid occlusion followed by 4 h reperfusion model was used to induce cerebral infarction. Percent infarction, oxidative stress markers (malondialdehyde, catalase, superoxide dismutase) and inflammatory markers (myeloperoxidase, TNF-α, IL-6, ICAM-1 and IL-10) were measured. TNF-α, IL-6, IL-10, and intracellular adhesive molecule-I (ICAM-1) levels were quantified by enzyme-linked immunosorbent assay (ELISA). Resveratrol produced significant dose-dependent reduction in percent cerebral infarct volume. At resveratrol 20 mg/kg dose, there was a significant reduction in oxidative stress and inflammatory markers like malondialdehyde, TNF-α, IL-6, myeloperoxidase and ICAM-I and in contrast there was a significant increase in anti-oxidants and anti-inflammatory markers like superoxide dismutase, catalase and IL-10 levels. Resveratrol showed significant cerebroprotective action mediated by anti-oxidant and anti-inflammatory mechanisms.

Evaluation of a decision support system to predict preoperative investigations.

BACKGROUND: We have developed the 'Optimising Surgical Care and Assessment Record' (OSCAR), a clinical decision support system, to help nurses in predicting necessary preoperative investigations before surgery. OSCAR applies the hospital's protocols, which are based on the National Institute for Health and Clinical Excellence guidelines, to the patient's medical history and surgical details before recommending required investigations. METHODS: We selected case notes of 50 patients randomly from the OSCAR system that were recorded between October 2006 and January 2007. To form a reference standard, these case histories were anonymized and then sent to 10 consultant anaesthetists across the country. They were asked to study the case history and choose which tests they would carry out and which they would not. Then we have evaluated OSCAR's ability to predict the necessary investigations and the nurses' judgement, in comparison with the reference standard. RESULTS: OSCAR's ability to identify which investigations should be carried out, that is, its sensitivity, was 91.5% and its ability to identify which investigations not to carry out, that is, its specificity, was 82.7%. OSCAR was consistent in predicting investigations for differing severities of surgery, for ASA grade and gender. We were unable to demonstrate any overall difference between OSCAR and the nurse's ability to predict preoperative investigations. When combining the nurse's predictions with OSCAR's recommendations, an even greater sensitivity of 98.2% could be achieved. CONCLUSIONS: OSCAR's prediction algorithm cannot replace the nurse's judgement, but it can be used as a supplementary decision aid to promote consistency and improve accuracy.

Reduced perception of pain in schizophrenia: its relevance to the clinical diagnosis of compartment syndrome.

An atypical presentation of compartment syndrome is reported in a chronic schizophrenic patient with a closed upper tibial fracture. The features of this case and a review of the literature pertaining to pain perception in this group of patients are presented to raise clinical awareness of this combination of disorders, which may lead to delayed treatment of a surgical emergency, consequent on lack of development of classic symptoms in these patients. We suggest continuous intracompartmental pressure monitoring, even in awake schizophrenic patients with injuries at risk of compartment syndrome.

Alcohol-associated admissions to an adult intensive care unit: an audit.

BACKGROUND AND OBJECTIVE: Excessive alcohol consumption is a major cause for premature death and preventable ill health in the whole population. We set out to audit admissions to the intensive care unit (ICU) of our large teaching hospital with respect to alcohol-related admissions. METHODS: A prospective audit was conducted into alcohol-associated admissions to our university hospital adult ICU over 12 months. The following data were collected for each patient admitted: age, gender, diagnosis and amount of alcohol consumption, APACHE II score, and the probability of death. RESULTS: Patients with definite alcohol consumption constituted 39.1% (124 patients) of all admissions (317 patients) to the ICU. In Group 1 (89 patients), the admission was directly associated with alcohol consumption, which included heavy alcohol consumption. Group 2 (35 patients) consisted of 'social drinkers'; and Group 3 was composed of patients who denied any alcohol intake. Group 1 had a high median APACHE II score of 19 (range 4-35) and a significantly higher mortality rate (41.6%) than Group 3 (18.4%, P < 0.001) or the entire sample studied (23.7%, P < 0.001). The results also demonstrated an incidence of pneumonia of 29.2% (26 patients) in alcohol-associated admissions compared with 22.8% (eight patients) in Group 2 and 21.8% (19 patients) in Group 3. Trauma admissions amounted to 11.4% of the patients studied (24/211 patients), 17 (70.8%) of whom were directly associated with alcohol and it included 11 pedestrians. CONCLUSIONS: Alcohol may play a major role in the admission and mortality of ICU patients. Further investigations are warranted because our sample size is so small.