Total intravenous anaesthesia with propofol and remifentanil for elective neurosurgical procedures: An audit of early postoperative complications

Background and objectives: This was a prospective audit to assess the incidence and characteristics of early postoperative complications in the recovery room in extubated patients after elective neurosurgical procedures using propofol and remifentanil-based total intravenous anaesthesia. Methods: Vital signs (temperature, conscious level, respiratory rate, oxygen saturation, pulse and blood pressure) and postoperative complications (shivering, nausea, vomiting and cardiorespiratory) were analysed in 145 adult patients over a 1-yr period. Results: The overall shivering, postoperative nausea and vomiting and postoperative hypertension (systolic blood pressure more than 25% of the preoperative value) incidences were 30.3%, 16.6% and 35.2%, respectively. Fifty-one percent of the patients had at least one of the above complications. The complication rates were found to be widely different among various types of neurosurgery. The surgical procedures were divided into five groups: supratentorial craniotomy, posterior fossa craniotomy, intracranial vascular procedures, transphenoidal hypophysectomy and extracranial procedures. Median extubation time was similar in all groups and patients were fully conscious with no hypoxia in the recovery room. The intracranial vascular group had the highest shivering and postoperative nausea and vomiting rates (58.8% and 29.4%, respectively). In the supratentorial craniotomy group, 46% of the patients had hypertension. The overall complication rate (presence of any complications) was highest in the supratentfial craniotomy (55.4%), posterior fossa craniotomy (75%) and intracranial vascular (76.5%) groups. Shivering and overall complication rate was significantly related to the anaesthetic time (P ≤ 0.001 and 0.02, respectively). Conclusions: Despite the potential advantages of total intravenous anaesthesia in titratability, rapid return of consciousness and reduced respiratory complications, making it suitable for planned extubation at the end of neurosurgery, the postoperative complications of shivering, postoperative nausea and vomiting and hypertension were still high. © 2006 Copyright European Society of Anaesthesiology.published_or_final_versio

Source apportionment of ambient volatile organic compounds in major cities in Australia by positive matrix factorisation.

Source apportionment of the 6-daily, 24 h volatile organic compound (VOC) samples collected during 2003–2004 in Melbourne, Sydney and Brisbane was carried out using the Positive Matrix Factorisation software (PMF2). Fourteen C4-C10 VOCs were chosen for source apportionment. Biogenic emissions were not covered in this study because tracer VOCs such as isoprene were not measured. Five VOC source factors were identified, including the ‘evaporative / fuel distribution’ factor (contribute to 37% of the total mass of the 14 VOCs on average), the ‘vehicle exhaust / petrochemical industry’ factor (24%), the ‘biomass burning’ factor (13%), the ‘architectural surface coatings’ factor (5%) and the ‘other sources’ factor (14%). The relative contributions of the source factors to the ambient VOC concentration at the sampling sites were comparable to the relative emission loads of the local sources in Australian air emission inventories. The high contribution from evaporative emissions indicates that introduction of reduction measures for evaporative emissions could substantially reduce the VOC emissions in Australian cities. The total VOC mass and the contributions from vehicle related sources and biomass burning were higher in winter and autumn, while the contributions from surface coatings were higher in summer. © 2008, Clean Air Society of Australia and New Zealan

Activation kinetics of single P2X receptors

After the primary structure of P2X receptors had been identified, their function had to be characterized on the molecular level. Since these ligand-gated ion channels become activated very quickly after binding of ATP, methods with adequate time resolution have to be applied to investigate the early events induced by the agonist. Single-channel recordings were performed to describe conformational changes on P2X2, P2X4, and P2X7 receptors induced by ATP and also by allosteric receptor modifiers. The main results of these studies and the models of P2X receptor kinetics derived from these observations are reviewed here. The investigation of purinoceptors by means of the patch clamp technique following site-directed mutagenesis will probably reveal more details of P2X receptor function at the molecular level

Riparian buffers can help mitigate biodiversity declines in oil palm agriculture

Agricultural expansion is a primary driver of biodiversity decline in forested regions of the tropics. Consequently, it is important to understand the conservation value of remnant forests in production landscapes. In a tropical landscape dominated by oil palm (Elaeis guineensis), we characterized faunal communities across eight taxa occurring within riparian forest buffers, which are legally protected alongside rivers, and compared them to nearby recovering logged forest. Buffer width was the main predictor of species richness and abundance, with widths of 40–100 m on each side of the river supporting broadly equivalent levels of biodiversity as compared to logged forest. However, width responses varied markedly among taxa, and buffers often lacked forest-dependent species. Much wider buffers than are currently mandated are needed to safeguard most species. The largest biodiversity gains are achieved by increasing relatively narrow buffers. To provide optimal conservation outcomes in tropical production landscapes, we encourage policy makers to prescribe width requirements for key taxa and different landscape contexts

Macular thickness measurements in healthy Norwegian volunteers: an optical coherence tomography study

<p>Abstract</p> <p>Background</p> <p>Ethnic, intersubject, interoperator and intermachine differences in measured macular thickness seem to exist. Our purpose was to collect normative macular thickness data in Norwegians and to evaluate the association between macular thickness and age, gender, parity, and contraception status.</p> <p>Methods</p> <p>Retinal thickness was measured by Stratus Optical Coherence Tomography in healthy subjects. Mean macular thickness (MMT) was analyzed by repeated measures ANOVA with three dependent regional MMT-variables for interaction with age, gender, parity and oral contraception use. Exploratory correlation with age by the Pearson correlation test, both before and after stratification by gender was performed. Differences in MMT between older and younger subjects, between oral contraception users and non-users, as well as parous and nulliparous women were studied by post-hoc Student's t-tests.</p> <p>Results</p> <p>Central MMT in Norwegians was similar to values earlier reported in whites. MMT in central areas of 1 and 2.25 mm in diameter were higher in males than in females. In younger subjects (≤43 years) differences in MMT between genders were larger than in the mixed age group, whereas in older subjects (>43 years) the small differences did not reach the set significance level. No differences were found in minimal foveolar thickness (MMFT) between the genders in any age group.</p> <p>Mean foveal thickness (1 mm in diameter) was positively associated with age in females (r = 0.28, p = 0.03). MMFT was positively associated with age in all groups and reached significance both in females and in mixed gender group (r = 0.20, p = 0.041 and r = 0.26, p = 0.044 respectively).</p> <p>Mean foveal thickness and MMFT were significantly higher in parous than in nulliparous women, and age-adjusted ANOVA for MMFT revealed a borderline effect of parity.</p> <p>Conclusions</p> <p>Age and gender should be taken into consideration when establishing normal ranges for MMT in younger subjects. The gender difference in retinal thickness in young, but not older adults suggests a gonadal hormonal influence. The possible association between parity and retinal structure and its clinical relevance, should be studied further.</p

Large venous air embolism in the sitting position despite monitoring with transoesophageal echocardiography

A 49-year-old male with neurofibromatosis type II was scheduled for posterior fossa craniotomy and excision of a right acoustic neuroma and placement of an auditory brainstem implant in the sitting position. Intra-operatively, the patient was monitored with transoesophageal echocardiography which detected two major episodes of venous air embolism. Despite immediate treatment the patient's gas exchange progressively worsened during surgery and a chest X-ray showed extensive bilateral pulmonary infiltrates. The patient developed acute respiratory distress syndrome and required inotropic support in the intensive care unit. Although transoesophageal echocardiography allowed rapid detection of venous air embolism, there was no evidence of therapeutic benefit. © 2005 Blackwell Publishing Ltd.link_to_subscribed_fulltex

Postdural puncture tinnitus [10]

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Anesthetic management of Cesarean delivery in a patient with hypoplastic anemia and severe pre-eclampsia

Purpose: To describe the anesthetic management of Cesarean delivery in a patient with hypoplastic anemia and severe preeclampsia. Clinical features: A 28-yr-old parturient with a history of thrombocytopenia was admitted with signs of pre-eclampsia (blood pressure of 140/90 mmHg, heavy proteinuria and moderate bilateral ankle edema) at 25 weeks of gestation. Laboratory studies revealed pancytopenia (hemoglobin 6.4 g·L-1, white cell count 3.43 × 109·L-1, platelet count 20 × 109·L-1) and bone marrow biopsy showed hypoplastic anemia. As pre-eclampsia worsened, a Cesarean delivery was performed at 27 weeks with prophylactic platelet transfusion and meticulous blood pressure control. The procedure was uneventful, conducted under general anesthesia with an estimated blood loss of around 600 mL and a live female baby was delivered. Postoperatively her blood pressure and neurological symptoms improved but thrombocytopenia remained at discharge. Conclusions: Hypoplastic anemia is rare in pregnancy but it poses an increased risk for both mother and fetus. The mother is at risk of life-threatening episodes of bleeding and infection and a multidisciplinary team approach (obstetrician, anesthesiologist, hematologist and pediatrician) is essential. An accurate assessment of the hematological condition should be made and abnormalities corrected before surgery. Regional anesthesia may not be possible in this circumstance.link_to_subscribed_fulltex