Slag dusts from Kabwe (Zambia): Contaminant mineralogy and oral bioaccessibility.

The former Pb-Zn mining town of Kabwe in central Zambia is ranked amongst the worst polluted areas both in Africa and in the world. The fine dust particles from the ISF and Waelz slags deposited in Kabwe represent a health risk for the local population. Here, we combined a detailed multi-method mineralogical investigation with oral bioaccessibility testing in simulated gastric fluid (SGF; 0.4 M glycine, pH 1.5, L/S ratio of 100, 1 h, 37 °C) to evaluate the risk related to the incidental dust ingestion. The slag dust fractions contain up to 2610 mg/kg V, 6.3 wt% Pb and 19 wt% Zn. The metals are mainly bound in a slag glass and secondary phases, which formed during the slag weathering or were windblown from nearby tailing stockpiles (carbonates, Fe and Mn oxides, phosphates, vanadates). The bioaccessible fractions (BAFs) are rather high for all the main contaminants, with the BAF values generally higher for the ISF slags than for the Waelz slags: Pb (24-96%), V (21-100%) and Zn (54-81%). The results clearly indicate the potential risks related to the incidental slag dust ingestion. Even when a conservative value of the dust daily intake (100 mg/day) is considered, the daily contaminant intake significantly exceeds the tolerable daily intake limits, especially for Pb â‰« V > Zn. At higher ingestion rates, other minor contaminants (As, Cd) also become a health risk, especially for children. The slag heaps in Kabwe should be fenced to prevent local people entering and should be covered to limit the dust dispersion.

Indications for General versus Local Anesthesia during Carotid Endarterectomy.

BACKGROUND AND STUDY AIMS: Both general anesthesia (GA) and local anesthesia (LA) are used in our department for carotid endarterectomy. The decision of which anesthetic technique to use during surgery is made on an individual basis. The aim of our study was to analyze the reasons for using GA or LA. MATERIAL AND METHODS: The reasons that led to the selection of either GA or LA were analyzed retrospectively in a group of 409 patients. RESULTS: GA was used in 304 patients (74%) and LA in 105 patients (26%). The reasons for a preference for GA were clopidogrel use (88 patients), patient preference (80), increased risk of shunt insertion (43), unfavorable anatomical conditions (41), surgeon preference (21), simultaneous carotid endarterectomy and cardiac surgery (18), emergent carotid endarterectomy (12), and sleep apnea syndrome (1). The reasons for selecting LA were internal comorbidities (46 patients), patient preference (39), unavailability of intraoperative electrophysiologic monitoring (15), and pacemaker (5). CONCLUSION: GA is the dominant choice for carotid endarterectomy in our department because of its prevailing benefits and its preference among neurosurgeons and patients. However, in some subgroups of patients, LA is preferable. An optimal approach is therefore an individual indication for both anesthesia techniques.

Cognitive impairment measured by event-related potentials during early and late postoperative period following intravenous or inhalation anaesthesia.

OBJECTIVE: This study investigated modification in cognitive function following inhalation (IA) and total intravenous (TIVA) anaesthesia measured using auditory ERPs (Event Related Potentials). METHODS: Auditory ERPs examination with N1, P3a and P3b component registration was carried out one day before surgery (D-1) and on the first (D+1), sixth (D+6) and 42nd (D+42) days after surgery. Results were compared between two anaesthetic groups. RESULTS: On D+1, N1 latency was increased in the IA group. A significant reduction was observed in amplitude of the P3a component on D+6, which persisted up to D+42 for both IA and TIVA groups. A reduction in the amplitude of P3b on D+1 with normalization by D+6 was found in both groups as well. CONCLUSIONS: Intravenous and inhalation anaesthesia lead to similar changes in cognitive function as determined by ERPs, both during the early and late postoperative periods. It cannot be clearly confirmed whether the observed effects are due to anaesthesia or other unmonitored perioperative factors. SIGNIFICANCE: Post anaesthetic changes represent a subclinical impairment; nevertheless, they represent a potential risk for subsequent development of cognitive difficulties.

Urgent extracranial-intracranial bypass in the treatment of acute hemodynamic ischemic stroke: case report.

Extracranial-intracranial (EC-IC) bypass surgery is performed to allow flow augmentation in selected cases of occlusive cerebrovascular disease. The majority of EC-IC bypasses are described as an elective procedure in the prevention of hemodynamic ischemic stroke. There is only limited and controversial experience of superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis performed under urgent circumstances as a treatment of acute cerebral ischemia. We describe a unique case of a 75-year-old patient presenting with acute progressive hemodynamic ischemia after carotid endarterectomy (CEA), which developed contralaterally to the performed CEA in the region of chronic internal carotid artery (ICA) occlusion. Urgent performance of a standard STA-MCA bypass rapidly improved the cerebral hemodynamic and had an excellent therapeutic effect. The patient had recovered completely within 4 weeks of surgery. The role of urgent EC-IC bypass for stroke treatment is discussed.

The impact of general versus local anesthesia on early subclinical cognitive function following carotid endarterectomy evaluated using P3 event-related potentials.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is detected in 25% of patients undergoing carotid endarterectomy (CEA). The mechanism of POCD is poorly understood, but it is believed that general anesthesia (GA) itself may contribute significantly to POCD. The aim of our prospective study was to compare, with the aid of event-related potentials, the impact of general anesthesia (GA) and local anesthesia (LA) on POCD in patients undergoing CEA. METHODS: Sixty patients were included in this study and were divided into two groups: CEA was performed in 30 patients placed under GA (total intravenous anesthesia), herein the GA group, while 30 patients underwent CEA under LA (cervical plexus block), herein LA group. Cognitive outcome was assessed with the use of auditory event-related potentials (ERPs), P3 response. The measurements were taken before surgery (pre-op) and on the first (1.post-op) and the sixth postoperative days (6.post-op). RESULTS: Preoperative cognitive functions did not differ significantly between the two groups. A significant decrease in P3 amplitude was found on the first postoperative day (1.post-op) in the GA group (p = 0.0005), but normalization of P3 amplitude was detected at the second postoperative measurement (6.post-op). The patients operated on under local anesthesia (LA group) showed stable P3 amplitudes in all three measurements. No significant changes in P3 latencies were observed in either group. There were no significant differences between the two groups regarding demographic characteristics, preoperative and postoperative clinical condition, percentage significance of carotid artery stenosis, duration of carotid cross-clamping or in the frequency of shunt use (zero frequency for both groups). CONCLUSIONS: Our study showed that general anesthesia, used for patients undergoing CEA, negatively influenced cognitive function during the immediate period after surgery (the first postoperative day). However, by the sixth postoperative day, this cognitive impairment was no longer being detected. POCD occurring shortly after carotid endarterectomy is the result of general anesthesia, which is probably an independent evoking factor in itself. The cognitive deficit recorded only during the immediate postoperative period, is not a negative effect of GA but merely a side-effect and thus GA should not be considered inferior to LA for use during CEA.

[The impact of neuroprotection on brain metabolism during carotid endarterectomy]. / Vliv neuroprotekce na mozkové metabolické parametry pri karotické endarterektomii.

BACKGROUND: The primary objective of this study was to evaluate the impact of neuroprotection, administered during carotid endarterectomy, on brain metabolism. The secondary objective was to assess the impact on clinical outcome of the resulting changes to brain metabolism. METHODS: A total of 35 patients underwent carotid endarterectomy with prophylactic combined neuroprotection (Sendai cocktail: Manitol, Phenhydan, Solumedrol, Tokoferol; Cerebrolysin; fraction of inspired oxygen (FiO2) = 1, middle arterial pressure (MAP) = 100 mm Hg, total intravenous anaesthesia--TIVA). The influence of neuroprotection on brain metabolism (S100B, glycaemia, lactate, pH, jugular vein bulb oxygen saturation--SvjO2) was evaluated. Metabolic parameters were acquired from the jugular bulb during surgery, just before unclamping of the vessel. The clinical outcome was evaluated by NIHSS (National Institutes of Health Stroke Scale). There were 35 patients in the control group who where operated on without any neuroprotection. The results from both groups of patients were compared and statistically analyzed. RESULTS: Postoperative NIHSS did not change in any patients in either group. An intraoperative shunt was not inserted in any patients in either group. In the group with neuroprotection there were significantly higher levels of S100B (median 0.117 vs. 0.088; p < 0.0182), lactate (median 1.92 vs. 1.020; p < 0.0006), glycaemia (median 9.5 vs. 8.2; p < 0.0243), and SvjO2 (median 0.79 vs. 0.65; p < 0.0001). There were no postoperative changes to NIHSS in either group. CONCLUSIONS: Neuroprotection administered before carotid endarterectomy influences some parameters of brain metabolism both positively and negatively, but with no impact on clinical outcome.