Next-generation of instrumental odour monitoring system (IOMS) for the gaseous emissions control in complex industrial plants.

Odour emissions from complex industrial plants may cause potential impacts on the surrounding areas. Consequently, the validation of effective tools for the control of the associated environmental pressures, without hindering economic growth, is strongly needed. Nowadays, senso-instrumental methods by using Instrumental Odour Emissions Systems (IOMSs) is among the most attractive tool for the continuous monitoring of environmental odours, allowing the possibility of obtaining real-time information to support the decision-making process and proactive approach. The systems complexity and scarcity of real data limited their wider full-scale employment. The study presents an advanced prototype of IOMS for the continuous classification and quantification of the odours emitted in ambient air by complex industrial plants, to continuously control the plants emissions with backwards approach. The IOMS device was designed and optimized and included the system for the automatic control of the conditions inside the measurement chamber. The designed operational procedures were presented and discussed. Results highlighted the influence of temperature and air flow rate for the measurement repeatability. Accurate prediction model was created and optimized and resulted able to distinguish 3 different industrial odour sources with accuracy approximately equal to 96%. The models were optimized thanks to the software features, which allowed to automatically apply the designed statistical procedures on the identified dataset with different pre-processing approach. The usefulness of having a fully-developed and user-friendly flexible system that allowed to select and automatically compare different settings options, including the different feature extraction methods, was demonstrated in order to identify the best prediction model.

Open repair for ruptured abdominal aortic aneurysm: is it possible to predict survival?

The aim of the study was to determine variables that could be used to predict survival in patients with ruptured abdominal aortic aneurysm (RAAA) and to assess the accuracy of the Glasgow Aneurysm Score (GAS) and the Acute Physiology Chronic Health Evaluation II (APACHE-II). From January 1998 to July 2006, 103 patients underwent operations for RAAA. For each patient, 44 variables were retrospectively recorded in a database. Data were analyzed with univariate and multivariate methods. In the univariate analysis significant predictors of death were hypotension (p=0.001), preexisting peripheral vascular disease (p<0.001), renal insufficiency (p=0.037), chronic obstructive pulmonary disease (p=0.028), level of HCO(3)(-) (p<0.001), intraperitoneal rupture (p=0.001), blood transfused (p<0.001), cardiac complications (p<0.001), and APACHE-II score (p=0.001). Multivariate analysis confirmed statistical significance for coexisting peripheral vascular disease (p<0.001), diastolic blood pressure at admission <60 mm Hg (p=0.039), APACHE-II score >18.5 (p=0.025), HCO(3)(-) <21 mg/dL (p<0.001), and intraperitoneal rupture of the aneurysm (p=0.011) as predictors of death. Results of the study suggested that different factors can be helpful in identifying those patients whose operative risk is prohibitive. APACHE-II, contrary to GAS, is an accurate system to predict postoperative death after repair for RAAA.

Tracheal esophageal combitube: a useful airway for morbidly obese patients who cannot intubate or ventilate.

The tracheal esophageal combitube has been successfully used in many difficult airway circumstances. We report the dramatic case of a morbidly obese patient with a well-known difficult airway who was successfully rescued from a cannot ventilate-cannot intubate situation in our critical care unit by using the tracheal esophageal combitube. Surgical tracheostomy was performed while she was mechanically ventilated through the tracheal esophageal combitube. The tracheal esophageal combitube is a very important device that should be kept available in all cases of morbidly obese airway management.

Activity of GH/IGF-I axis in trauma and septic patients during artificial nutrition: different behavior patterns?

The aim of this study was to compare several parameters of GH/IGF-I axis activity in septic and trauma patients during Intensive Care Unit (ICU) stay. To this goal, 13 patients with sepsis (SEP) and 16 with trauma (TRA) were studied. Thirty-three adult subjects (AS) were studied as controls. Serum IGF-I and -II, IGFBP-1, -2 and -3, GH and GHBP levels were studied on day 1, 3, 5 and 7 after ICU admission, during comparable artificial nutrition in SEP and TRA and basally in AS. In 5 patients with SEP and 6 with TRA, the GH response to GHRH was evaluated on day 3. On ICU day 1, IGF-I and -II and IGFBP-3 in SEP were lower (p<0.05) than in TRA which, in turn, were lower (p<0.01) than in AS. IGF-I increased (p<0.05) both in SEP and TRA, but, on ICU day 7, those in SEP persisted lower than in TRA, which became similar to those in AS. IGF-II levels increased (p<0.05) in SEP only, persisting lower (p<0.05) than in TRA. On ICU day 1, GH in SEP and TRA were similar and did not vary until day 7, overlapping those in AS. The GH response to GHRH in SEP and TRA was similar and lower (p<0.01) than in AS. These findings indicate that IGF-I activity is impaired more in septic than in trauma patients. Reduced IGF-I activity probably reflects peripheral GH resistance though basal and GHRH-induced GH levels were not increased in these conditions.

A single institution's experience (1982-1999) with plasma-exchange therapy in patients with fulminant hepatic failure.

Fulminant hepatic failure is a rare, but often fatal complication of acute viral hepatitis. This condition, in absence of orthotopic liver transplantation (OLTx) surgery, is associated with a high mortality rate, despite the improvement of general intensive care. Plasma-exchange (PEx) therapy has been long used to treat FHF, in particular by removing toxic substances and correcting the severe coagulopathy. In this study we describe our experience with PEx treatment of FHF, beginning in 1982. Seventy patients affected with FHF due to various causes (HBV = 40; cryptogenic/non-A, non-E = 15; Amanita phalloides = 8; other = 7) were treated with PEx (altogether 348 sessions). Overall survival rate, comprising patients undergoing OLTx, was 51%, a little higher than what we observed in patients (N = 49) treated solely by PEx, i.e., 41%. The best outcome predictor was FHF aetiology, owing to the good survival rate in patients with Amanita phalloides intoxication and the very poor prognosis of patients suffering from cryptogenic/non-A, non-E FHF. Moreover, the marked increase in prothrombin time and alpha-fetoprotein levels after 48 hours from admission was associated with a good prognosis, whereas the patient's age and coma grade were not clearly predictive of survival. Additionally, lymphocyte subpopulation, resulting in a CD4/CD8 ratio lower than 1.0 along with CD8 activation with HLA-DR strong expression, were associated with a high rate of mortality and morbidity. Our data indicate that PEx therapy can improve survival in patients with sufficient residual capacity of liver regeneration. Moreover, the identification of certain prognostic factors may be useful for the rational planning of therapeutic strategy in FHF.

Relationship between central venous pressure and bioimpedance vector analysis in critically ill patients.

OBJECTIVE: To assess the relationship between central venous pressure values and bioelectrical impedance vector analysis (BIVA), which may be used as complementary methods in the bedside monitoring of fluid status. DESIGN: Cross-sectional evaluation of a consecutive sample. SETTING: Intensive care unit of a university hospital. PATIENTS: One hundred and twenty-one consecutive Caucasian, adult patients of either gender, for whom routine central venous pressure measurements were available. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Central venous pressure values and impedance vector components (i.e., resistance and reactance) were determined simultaneously. Total body water predictions were obtained from regression equations according to either conventional bioimpedance analysis or anthropometry (Watson and Hume formulas). Variability of total body water predictions was unacceptable for clinical purposes. Central venous pressure values significantly and inversely correlated with individual impedance vector components (r2 = .28 and r2 = .27 with resistance and reactance, respectively), and with both vector components together (R2 = .31). Patients were classified in three groups according to their central venous pressure value: low (0 to 3 mm Hg); medium (4 to 12 mm Hg); and high (13 to 20 mm Hg). Three BIVA patterns were considered: vectors within the target (reference) 75% tolerance ellipse (normal tissue hydration); long vectors out of the upper pole of the target (dehydration); and short vectors out of the lower pole of the target (fluid overload). The agreement between BIVA and central venous pressure indications was good in the high central venous pressure group (93% short vectors), moderate in the medium central venous pressure group (35% normal vectors), and poor in low central venous pressure group (10% long vectors). CONCLUSIONS: Central venous pressure values correlated with direct impedance measurements more than with total body water predictions. Whereas central venous pressure values >12 mm Hg were associated with shorter impedance vectors in 93% of patients, indicating fluid overload, central venous pressure values <3 mm Hg were associated with long impedance vectors in only 10% of patients, indicating tissue dehydration. The combined evaluation of intensive care unit patients by BIVA and central venous pressure may be useful in therapy planning, particularly in those with low central venous pressure in whom reduced, preserved, or increased tissue fluid content can be detected by BIVA.

Low IGF-I levels are often uncoupled with elevated GH levels in catabolic conditions.

Increased GH together with decreased IGF-I levels pointing to peripheral GH insensitivity in critically ill patients have been reported by some but not by other authors. To clarify whether elevated GH levels are coupled with low IGF-I levels in all catabolic conditions, basal GH and IGF-I levels were evaluated in patients with sepsis (SEP, no.=13; age [mean+/-SE]=59.2+/-1.2 yr), trauma (TRA, no.=16; age=42.3+/-3.4 yr), major burn (BUR, no.=26; age=52.8+/-4.2 yr) and post-surgical patients (SUR, no.=11; age=55.0+/-4.7 yr) 72 hours after ICU admission or after cardiac surgery. GH and IGF-I levels were also evaluated in normal subjects (NS, no.=75; age=44.0+/-1.5 yr), in adult hypopituitaric patients with severe GH deficiency (GHD, no.=54; age=44.8+/-2.3 yr), in patients with liver cirrhosis (LC, no.=12; age=50.4+/-2.8 yr) and in patients with anorexia nervosa (AN, no.=19; age=18.7+/-0.8 yr). Basal IGF-I and GH levels in GHD were lower than in NS (68.6+/-6.4 vs 200.9+/-8.7 microg/l and 0.3+/-0.1 vs 1.4+/-0.2 microg/l; p<0.01). On the other hand, AN and LC showed IGF-I levels (70.4+/-9.1 and 52.4+/-10.5 microg/l) similar to those in GHD while GH levels (10.0+/-2.8 and 7.9+/-2.1 microg/l) were higher than those in NS (p<0.01). IGF-I levels in SEP (84.5+/-8.8 microg/l) were similar to those in GHD, AN and LC and lower than those in NS (p<0.01). IGF-I levels in BUR (105.2+/-10.9 microg/l) were lower than in NS (p<0.01) but higher than those in GHD, AN, LC and SEP (p<0.01). On the other hand, in TRA (162.8+/-17.4 microg/l) and SUR (135.0+/-20.7 microg/l) IGF-I levels were lower but not significantly different from those in NS and clearly higher than those in GHD, AN, LC, SEP and BUR. Basal GH levels in SEP (0.6+/-0.2 microg/l), TRA (1.8+/-0.5 microg/l), SUR (2.2+/-0.5 microg/l) and BUR (2.2+/-0.5 microg/l) were similar to those in NS, higher (p<0.05) than those in GHD and lower (p<0.01) than those in AN and LC. In conclusion, our data demonstrate that low IGF-I levels are not always coupled with elevated GH levels in all catabolic conditions. Differently from cirrhotic and anorectic patients, in burned and septic patients GH levels are not elevated in spite of very low IGF-I levels similar to those in panhypopituitaric GHD patients. These findings suggest that in some catabolic conditions peripheral GH insensitivity and somatotrope insufficiency could be concomitantly present.

Maintenance and recovery characteristics of sevoflurane anaesthesia in adult patients. A multicenter, randomized comparison with isoflurane.

BACKGROUND: The goal of the present multicenter, prospective, randomized clinical investigation was to compare the clinical efficacy and safety of sevoflurane and isoflurane during maintenance of and recovery from general anaesthesia in adult patients. METHODS: With the approval of the Ethical Committee and the patient informed consent, 143 ASA physical status I-II patients, aged 18-65 years, were randomized in order to receive either isoflurane (n = 71) or sevoflurane (n = 72) as the main general anaesthetic. After an oral diazepam (0.1-0.2 mg kg-1) and atropine (0.007-0.01 mg kg-1) premedication and a standardized intravenous induction, general anaesthesia was maintained by adjusting the end-tidal concentrations of the inhalational agent for the maintainance of cardiovascular stability. At the end of surgery the anaesthetic vapours were discontinued, and the neuromuscular block was reversed; the following times were recorded: time of eyes opening, time of command response and suitability for discharge from the recovery area. The occurrence of any untoward event was also recorded. Preoperatively and 24 hr after surgery, blood was collected in order to assess renal an hepatic functions. RESULTS: No differences in demography, duration of surgery, exposure to the inhalational agent and haemodynamic effects were observed between the two groups. Patients receiving sevoflurane showed shorter times for the achievement of extubation (median: 9 min versus 13 min, p = 0.002), eyes opening (median: 10 min versus 13 min, p = 0.002), command response (11 min versus 15 min, p = 0.002) and suitability for discharge from recovery room (median: 19 min versus 22 min, p < 0.05) than those receiving isofluorane. No intra- and intergroup differences were observed in pre- and post-operative laboratory testing of renal and hepatic function. DISCUSSION: We conclude that sevoflurane, when compared to isoflurane, provides a similarly safe maintenance but allows for a more rapid emergence from general anaesthesia.

Hangman's fracture in a paediatric patient: considerations for anaesthesia.

Cervical spine injuries are quite uncommon in children. When occurring, these lesions are of particular concern for the anaesthesiologist. This case refers to an hangman's fracture diagnosed in a four-month-old female infant, which probably occurred at birth. We describe the anaesthetic management adopted in this infant undergoing diagnostic procedures and conservative treatment. The problems related to airway control and the anaesthetic management utilized to diagnose and treat this unusual paediatric pathology are highlighted.

Respiratory depression following administration of low dose buprenorphine as postoperative analgesic after fentanyl balanced anaesthesia.

Opioids are among the most ancient and widely used drugs in anaesthesiology. The pharmacology of opioid analgesics and their receptors is a complex and not fully understood matter; even more complex are the interactions between different classes of opioids at both molecular and clinical levels. We want to report here a clinical observation to emphasize the importance of the theoretical basis of anaesthesiology. This paper contains a clinical observation of respiratory depression following the administration of buprenorphine as postoperative analgesic after balanced anaesthesia with fentanyl. The observed case is interpreted in the light of the pharmacokinetics and pharmacodynamics of the different classes of opioid drugs (agonists, agonists-antagonists, antagonists) and of the interactions with their respective receptors.

Spinal anesthesia in outpatient knee surgery: 22-gauge versus 25-gauge Sprotte needle.

Spinal anesthesia in day-care surgery is still controversial because of the possibility of postdural puncture headache (PDPH). The use of the Sprotte needle with a conical tip that spreads the dural fibers may reduce the incidence of PDPH. The aim of this study was to compare the 22-gauge and 25-gauge Sprotte needles with respect to PDPH and postoperative complaints in out-patients undergoing arthroscopy. The rate of spinal anesthesia failure and the feasibility of unilateral spinal anesthesia when using a low dose of anesthesia was also verified. For this randomized, prospective study, 234 patients undergoing elective arthroscopy were chosen. Patients were allocated randomly to have spinal anesthesia with either a 22-gauge or 25-gauge Sprotte needle. Dural puncture was performed with the patient in a lateral flexed decubitus position. After the injection of anesthetic solution (0.5-1.2 mL of 1% bupivacaine in 8% glucose) patients remained in the lateral decubitus position for 30 min. The time to regression of analgesia, time of micturition, and all postoperative complaints were recorded. The most frequent side effect was backache (10.2%) with a more frequent incidence in the group using the 22-gauge needle (14.5% and 5.9%, respectively). PDPH was recorded in only one patient (0.8%) in the group using the 22-gauge needle. The failure rate was 0.8%. Unilateral anesthesia was achieved in 88% of 213 patients. Our data indicate that the use of spinal block is a suitable technique in the ambulatory setting, with a low rate of unplanned hospital admission.(ABSTRACT TRUNCATED AT 250 WORDS)

Energy expenditure (EE) and substrate utilization (SU) in the perioperative period in orthotopic liver transplantation (OLTX).

12 patients were investigated with IC (Datex, Deltatrac) preoperatively and during the surgical procedure of OLTX, VO2, VCO2 were continuously measured and RQ, EE and SU were calculated considering the different periods of the procedure: preoperative resting EE: (PREE), anaesthesiological procedures (ANEE), liver preparation EE (LPEEE), liver removal EE (LREE), anhepatic phase EE (APEE), reperfusion, EE (RPEE) and end of operation EE (EOEE). EE were expressed as % respect value calculated with H.B. (Harris-Benedict) formula. Data were analyzed with Student T-test and p < 0.01** or < 0.05* PREE is typical in end stage liver disease with low RQ values and increased EE. Energy production depends on lipid utilization since liver gluconeogenesis and glycogen stores are impaired. Anesthesia reduces energy needs and production up to 50% of the preoperative values, reducing VO2 more than VCO2 and therefore an augmented RQ value over 1.0. SU analysis indicates an increased glucose and aminoacid utilization coupled with high nitrogen catabolism that continues in the postoperative period (from 0.08 0.01 gN/kg b.w. to 0.20 0.06 gN/kg b.w.). When the new liver is reperfused, VO2 increases more than VCO2 indicating the risk of reperfusion injury.

Prevalence of unsuspected myopathy in infants presenting for clubfoot surgery.

The objective of this study was an evaluation of the prevalence of myopathies in paediatric patients scheduled for orthopaedic surgery (clubfoot) performed under regional anaesthesia. Seventeen infants scheduled for lower limb orthopaedic surgery were studied to verify coexisting neuromuscular disorders with electromyography and muscle biopsy during surgery. All surgical procedures were performed under caudal block or spinal anaesthesia, associated with light general anaesthesia. No major cardiorespiratory, neurological or malignant hyperthermic complications (muscle rigidity, arrhythmias, hyperpyrexia) were observed. Combined neurological, electromyographic and biopsy studies showed a high rate of myopathic changes (70%). Performance of clubfoot surgery under light general anaesthesia with regional techniques was free from any problems. The high rate of myopathic changes (70%) observed in the muscle biopsies suggests that precautions should be taken with paediatric patients for clubfoot surgery and a regional anaesthesia technique with adequate monitoring may be helpful to prevent possible malignant hyperthermia related problems.