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1.  Remifentanil added to sufentanil-sevoflurane anesthesia suppresses hemodynamic and metabolic stress responses to intense surgical stimuli more effectively than high-dose sufentanil-sevoflurane alone 
BMC Anesthesiology  2015;15(1):3.
Background
Even extremely high-doses of the potent opioid, sufentanil, cannot reliably suppress stress responses to intense surgical stimuli such as sternotomy. The chemically related opioid remifentanil with its different pharmacokinetics and binding affinities for delta- and kappa-opioid receptors might be more effective in attenuating these responses.
Methods
ASA I-III patients scheduled for a surgical procedure with sternotomy under balanced anesthesia (sevoflurane and sufentanil 3 μg.kg-1 bolus, 0.017 μg.kg-1.min-1 infusion) were randomized into two groups. Patients in the study group were supplemented with remifentanil (2 μg.kg-1 bolus, 2–7 μg.kg-1.min-1 infusion) starting ten minutes before sternotomy. Heart rate, arterial blood pressures, cardiac index, ejection fraction, systemic vascular resistance index (SVRI), total body oxygen uptake (VO2) and electric dermal response were measured and compared between the groups.
Results
62 patients were studied (study group 32, control group 30). Systolic and mean arterial blood pressures, SVRI, VO2 and skin conductance increased during sternotomy and sternal spread in the control group but not in the study group. Systolic blood pressure increase: 7.5 ± 19 mmHg vs. -3.4 ± 8.9 (p = 0.005); VO2 increase: 31 ± 46% vs. -0.4 ± 32%; incidence of systolic blood pressure increase greater than 15 percent: 20% vs. 3% (p = 0.035) (control vs. study group).
Conclusion
High-dose remifentanil added to sevoflurane-sufentanil anesthesia suppresses the sympathoadrenergic response to sternotomy and sternal spread better than high-dose sufentanil alone.
Trial registration
Clinical Trial number: DRKS00004327, August 31, 2012
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2253-15-3) contains supplementary material, which is available to authorized users.
doi:10.1186/1471-2253-15-3
PMCID: PMC4322556  PMID: 25670917
Sternotomy; Stress response; Remifentanil; Intraoperative hypertension; Oxygen uptake
2.  Proteomic Selection of Immunodiagnostic Antigens for Trypanosoma congolense 
Animal African Trypanosomosis (AAT) presents a severe problem for agricultural development in sub-Saharan Africa. It is caused by several trypanosome species and current means of diagnosis are expensive and impractical for field use. Our aim was to discover antigens for the detection of antibodies to Trypanosoma congolense, one of the main causative agents of AAT. We took a proteomic approach to identify potential immunodiagnostic parasite protein antigens. One hundred and thirteen proteins were identified which were selectively recognized by infected cattle sera. These were assessed for likelihood of recombinant protein expression in E. coli and fifteen were successfully expressed and assessed for their immunodiagnostic potential by ELISA using pooled pre- and post-infection cattle sera. Three proteins, members of the invariant surface glycoprotein (ISG) family, performed favorably and were then assessed using individual cattle sera. One antigen, Tc38630, evaluated blind with 77 randomized cattle sera in an ELISA assay gave sensitivity and specificity performances of 87.2% and 97.4%, respectively. Cattle immunoreactivity to this antigen diminished significantly following drug-cure, a feature helpful for monitoring the efficacy of drug treatment.
Author Summary
Animal African Trypanosomosis (AAT) is a set of diseases whereby animals are infected with single-cell parasites that replicate in their bloodstream. The disease in cattle results in weight-loss and death, and AAT is a significant veterinary problem for sub-Saharan Africa. One of the principal trypanosome species responsible for AAT in cattle is Trypanosoma congolense and, although there are drug-treatments for these infections, current diagnostic methods are impractical for field use. Our aim was to discover protein molecules from the parasite to which infected animals make antibodies, to then make these proteins in bacteria and to subsequently demonstrate that they can be used to detect antibodies in cattle serum, thus diagnosing AAT. To discover the diagnostic proteins, we dissolved parasites in a detergent solution and applied them to beads coated with antibodies from infected cattle and to beads coated with antibodies from un-infected cattle. We then compared the proteins bound to each and selected those proteins that were at least 100-fold enriched by the infected cattle antibodies. We refined this list, according to practical and performance considerations, and settled on one protein, called Tc38630. Testing Tc38630 with cattle sera showed that it can detect about nine out of ten AAT infections.
doi:10.1371/journal.pntd.0002936
PMCID: PMC4055490  PMID: 24922510
3.  The effect of changing the sequence of cuff inflation and device fixation with the LMA-Supreme® on device position, ventilatory complications, and airway morbidity: a clinical and fiberscopic study 
BMC Anesthesiology  2014;14:2.
Background
The conventional sequence when using supraglottic airway devices is insertion, cuff inflation and fixation. Our hypothesis was that a tighter fit of the cuff and tip could be achieved with a consequently lower incidence of air leak, better separation of gastrointestinal and respiratory tracts and less airway morbidity if the device were first affixed and the cuff then inflated.
Methods
Our clinical review board approved the study (public registry number DRKS00003174). An LMA Supreme® was inserted into 184 patients undergoing lower limb arthroscopy in propofol-remifentanil anaesthesia who were randomly assigned to either the control (inflation then fixation; n = 92) or study group (fixation then inflation; n = 92). The cuff was inflated to 60 cmH2O. The patients’ lungs were ventilated in pressure-controlled mode with 5 cmH2O PEEP, Pmax to give 6 ml kg-1 tidal volume, and respiratory rate adjusted to end-tidal CO2 of 4.8 and 5.6 kPa. Correct cuff and tip position were determined by leak detection, capnometry trace, oropharyngeal leak pressure, suprasternal notch test, and lube-tube test. Bowl and cuff position and the presence of glottic narrowing were assessed by fiberscopic examination. Postoperative dysphagia, hoarseness and sore throat were assessed with a questionnaire. Ventilatory impairment was defined as a tidal volume < 6 ml kg-1 with Pmax at oropharyngeal leak pressure, glottic narrowing was defined as an angle between the vocal cords under 16 degrees.
Results
The incidence of incorrect device position (18% vs. 21%), failed ventilation (10% vs. 9%), leak pressure (24.8 vs. 25.2 cmH2O, p = 0.63), failed lube-tube test (16.3% vs. 17.6%) and glottic narrowing (19.3% vs. 14.1%, p = 0.35) was similar in both groups (control vs. study, resp.). When glottic narrowing occurred, it was more frequently associated with ventilatory impairment in the control group (77% vs. 39%; p = 0.04). Airway morbidity was more common in the control group (33% vs. 19%; p < 0.05).
Conclusions
Altering the sequence of cuff inflation and device fixation does not affect device position, oropharyngeal leak pressures or separation of gastrointestinal and respiratory tracts. It reduces the incidence of glottic narrowing with impaired ventilation and also perioperative airway morbidity.
doi:10.1186/1471-2253-14-2
PMCID: PMC3890616  PMID: 24387685
Supraglottic airway; Insertion sequence; Malposition; Endoscopic evaluation; Glottic narrowing; Ventilatory impairment; Airway morbidity
4.  Can breathing circuit filters help prevent the spread of influenza A (H1N1) virus from intubated patients? 
Introduction: In March 2010, more than 213 countries worldwide reported laboratory confirmed cases of influenza H1N1 infections with at least 16,813 deaths. In some countries, roughly 10 to 30% of the hospitalized patients were admitted to the ICU and up to 70% of those required mechanical ventilation. The question now arises whether breathing system filters can prevent virus particles from an infected patient from entering the breathing system and passing through the ventilator into the ambient air.
We tested the filters routinely used in our institution for their removal efficacy and efficiency for the influenza virus A H1N1 (A/PR/8/34).
Methods: Laboratory investigation of three filters (PALL Ultipor® 25, Ultipor® 100 and Pall BB50T Breathing Circuit Filter, manufactured by Pall Life Sciences) using a monodispersed aerosol of human influenza A (H1N1) virus in an air stream model with virus particles quantified as cytopathic effects in cultured canine kidney cells (MDCK).
Results: The initial viral load of 7.74±0.27 log10 was reduced to a viral load of ≤2.43 log10, behind the filter. This represents a viral filtration efficiency of ≥99.9995%.
Conclusion: The three tested filters retained the virus input, indicating that their use in the breathing systems of intubated and mechanically ventilated patients can reduce the risk of spreading the virus to the breathing system and the ambient air.
doi:10.3205/dgkh000209
PMCID: PMC3746606  PMID: 23967395
influenza virus A (H1N1); pandemic; viral spread; heat and moisture exchanger
5.  Randomized comparison of the i-gel™, the LMA Supreme™, and the Laryngeal Tube Suction-D using clinical and fibreoptic assessments in elective patients 
BMC Anesthesiology  2012;12:18.
Background
The i-gel™, LMA-Supreme (LMA-S) and Laryngeal Tube Suction-D (LTS-D) are single-use supraglottic airway devices with an inbuilt drainage channel. We compared them with regard to their position in situ as well as to clinical performance data during elective surgery.
Methods
Prospective, randomized, comparative study of three groups of 40 elective surgical patients each. Speed of insertion and success rates, leak pressures (LP) at different cuff pressures, dynamic airway compliance, and signs of postoperative airway morbidity were recorded. Fibreoptic evaluation was used to determine the devices’ position in situ.
Results
Leak pressures were similar (i-gel™ 25.9, LMA-S 27.1, LTS-D 24.0 cmH2O; the latter two at 60 cmH2O cuff pressure) as were insertion times (i-gel™ 10, LMA-S 11, LTS-D 14 sec). LP of the LMA-S was higher than that of the LTS-D at lower cuff pressures (p <0.05). Insertion success rates differed significantly: i-gel™ 95%, LMA-S 95%, LTS-D 70% (p <0.05). The fibreoptically assessed position was more frequently suboptimal with the LTS-D but this was not associated with impaired ventilation. Dynamic airway compliance was highest with the i-gel™ and lowest with the LTS-D (p <0.05). Airway morbidity was more pronounced with the LTS-D (p <0.01).
Conclusion
All devices were suitable for ventilating the patients’ lungs during elective surgery.
Trial registration
German Clinical Trial Register DRKS00000760
doi:10.1186/1471-2253-12-18
PMCID: PMC3434115  PMID: 22871204
Laryngeal mask airway; Leak pressure; Laryngeal Tube
6.  Effects of pulmonary acid aspiration on the lungs and extra-pulmonary organs: a randomized study in pigs 
Critical Care  2012;16(2):R35.
Introduction
There is mounting evidence that injury to one organ causes indirect damage to other organ systems with increased morbidity and mortality. The aim of this study was to determine the effects of acid aspiration pneumonitis (AAP) on extrapulmonary organs and to test the hypothesis that these could be due to circulatory depression or hypoxemia.
Methods
Mechanically ventilated anesthetized pigs were randomized to receive intrabronchial instillation of hydrochloric acid (n = 7) or no treatment (n = 7). Hydrochloric acid (0.1 N, pH 1.1, 2.5 ml/kg BW) was instilled into the lungs during the inspiratory phase of ventilation. Hemodynamics, respiratory function and computer tomography (CT) scans of lung and brain were followed over a four-hour period. Tissue samples of lung, heart, liver, kidney and hippocampus were collected at the end of the experiment.
Results
Acid instillation caused pulmonary edema, measured as increased extravascular lung water index (ELWI), impaired gas exchange and increased mean pulmonary artery pressure. Gas exchange tended to improve during the course of the study, despite increasing ELWI. In AAP animals compared to controls we found: a) cardiac leukocyte infiltration and necrosis in the conduction system and myocardium; b) lymphocyte infiltration in the liver, spreading from the periportal zone with prominent areas of necrosis; c) renal inflammation with lymphocyte infiltration, edema and necrosis in the proximal and distal tubules; and d) a tendency towards more severe hippocampal damage (P > 0.05).
Conclusions
Acid aspiration pneumonitis induces extrapulmonary organ injury. Circulatory depression and hypoxemia are unlikely causative factors. ELWI is a sensitive bedside parameter of early lung damage.
doi:10.1186/cc11214
PMCID: PMC3681347  PMID: 22380702
7.  Acute effects of intracranial hypertension and ARDS on pulmonary and neuronal damage: a randomized experimental study in pigs 
Intensive Care Medicine  2011;37(7):1182-1191.
Purpose
To determine reciprocal and synergistic effects of acute intracranial hypertension and ARDS on neuronal and pulmonary damage and to define possible mechanisms.
Methods
Twenty-eight mechanically ventilated pigs were randomized to four groups of seven each: control; acute intracranial hypertension (AICH); acute respiratory distress syndrome (ARDS); acute respiratory distress syndrome in combination with acute intracranial hypertension (ARDS + AICH). AICH was induced with an intracranial balloon catheter and the inflation volume was adjusted to keep intracranial pressure (ICP) at 30–40 cmH2O. ARDS was induced by oleic acid infusion. Respiratory function, hemodynamics, extravascular lung water index (ELWI), lung and brain computed tomography (CT) scans, as well as inflammatory mediators, S100B, and neuronal serum enolase (NSE) were measured over a 4-h period. Lung and brain tissue were collected and examined at the end of the experiment.
Results
In both healthy and injured lungs, AICH caused increases in NSE and TNF-alpha plasma concentrations, extravascular lung water, and lung density in CT, the extent of poorly aerated (dystelectatic) and atelectatic lung regions, and an increase in the brain tissue water content. ARDS and AICH in combination induced damage in the hippocampus and decreased density in brain CT.
Conclusions
AICH induces lung injury and also exacerbates pre-existing damage. Increased extravascular lung water is an early marker. ARDS has a detrimental effect on the brain and acts synergistically with intracranial hypertension to cause histological hippocampal damage.
Electronic supplementary material
The online version of this article (doi:10.1007/s00134-011-2232-2) contains supplementary material, which is available to authorized users.
doi:10.1007/s00134-011-2232-2
PMCID: PMC3127009  PMID: 21544692
ABI; ARDS; ELWI; CT scan; Organ dysfunction
8.  Effect of buspirone on thermal sensory and pain thresholds in human volunteers 
Background
Buspirone is a partial 5-HT1A receptor agonist. Animal studies have shown that modulation of serotoninergic transmission at the 5-HT1A receptor can induce analgesia in acute pain models. However, no studies have been published so far on the effects of serotonin receptor agonists on pain perception in humans.
Methods
The effects of buspirone (30 mg p.o.) on thermal sensory and pain thresholds were investigated in twelve female volunteers (26 ± 2 yrs) in a prospective, randomized, double-blind, double-dummy, placebo-controlled study with morphine (10 mg i.v.) as positive control.
Results
Morphine significantly increased the heat pain detection threshold (ΔT: placebo 1.0°C and 1.3°C, p < 0.05) at 60 minutes. Buspirone caused mild sedation in six participants at 60 minutes, but was without effect on any of the measured parameters.
Conclusion
Buspirone in the maximal recommended dose was without significant effect on thermal pain. However, as it is only a partial agonist at the 5-HT1A receptor and also acts on other receptor types, the negative results of the present study do not rule out a possible analgesic effect of more specific 5-HT1A receptor agonists.
doi:10.1186/1472-6904-9-12
PMCID: PMC2698897  PMID: 19480657

Results 1-8 (8)