Design and evaluation of an eye tracking support system for the scrub nurse.

BACKGROUND: The availability of an increasing number of medical devices in the digital operating room has led to increased interaction demands of the surgical staff. To counteract the risk of bacterial contamination induced by device interactions, touchless interaction techniques are required. Support systems based on eye tracking enable interaction while maintaining sterility and freeing the hands to manipulate surgical instruments. METHODS: A system using eye tracking glasses was developed. In an evaluation, participants completed tasks using gaze gestures. Three use cases were evaluated in an intraoperative setup. System performance, user acceptance, and workload were measured. RESULTS: The system was evaluated in a laboratory environment with 26 participants. The precision of the gaze gesture recognition is 97.9%, and the true positive rate is 98.5%. The participants rated the system useful and were satisfied. CONCLUSIONS: Touchless interaction ensures sterility, although the increasing availability of medical devices in the operating room.

Auditory display as feedback for a novel eye-tracking system for sterile operating room interaction.

PURPOSE: The growing number of technical systems in the operating room has increased attention on developing touchless interaction methods for sterile conditions. However, touchless interaction paradigms lack the tactile feedback found in common input devices such as mice and keyboards. We propose a novel touchless eye-tracking interaction system with auditory display as a feedback method for completing typical operating room tasks. Auditory display provides feedback concerning the selected input into the eye-tracking system as well as a confirmation of the system response. METHODS: An eye-tracking system with a novel auditory display using both earcons and parameter-mapping sonification was developed to allow touchless interaction for six typical scrub nurse tasks. An evaluation with novice participants compared auditory display with visual display with respect to reaction time and a series of subjective measures. RESULTS: When using auditory display to substitute for the lost tactile feedback during eye-tracking interaction, participants exhibit reduced reaction time compared to using visual-only display. In addition, the auditory feedback led to lower subjective workload and higher usefulness and system acceptance ratings. CONCLUSION: Due to the absence of tactile feedback for eye-tracking and other touchless interaction methods, auditory display is shown to be a useful and necessary addition to new interaction concepts for the sterile operating room, reducing reaction times while improving subjective measures, including usefulness, user satisfaction, and cognitive workload.

Reduced effect of intravenous antibiotic treatment on sinonasal markers in pulmonary inflammation.

BACKGROUND: Chronic bacterial rhinosinusitis is a common feature in Cystic fibrosis (CF) as mucociliary clearance in the sinonasal compartment is impaired. Aim of the present prospective study was to compare dynamics of inflammatory markers in the upper and lower airways (UAW/LAW) during systemic antibiotic therapy. METHODS: Nasal lavage and sputum of 16 CF-patients receiving an IV-antibiotic treatment against Pseudomonas aeruginosa and/ or Staphylococcus aureus were collected before and during treatment (median after 7.5 days). Cytological changes, DNA concentration, and inflammatory markers interleukin (IL)-4, IL-8, IL-13 and Myeloperoxidase (MPO) were assessed in samples from both airway compartments. RESULTS: Total cell count declined significantly in LAW-samples but not in UAW. Although MPO and IL-8 decreased significantly in both airway compartments, this was considerably more pronounced for LAW (median decrease MPO: LAW=9.8-fold vs UAW=1.75-fold, respectively; IL-8: LAW=3-fold vs UAW=1.9-fold, respectively). DISCUSSION: This is the first publication demonstrating substantially lower effects of IV-antibiotic treatment on sinonasal than on pulmonary inflammatory markers. Consequently, our findings highlight limitations of systemic antibiotic treatment to control infection in the sinonasal compartment. Primarily, we attribute this to the paranasal sinus ́ structure: these hollow organs, which in bacterial sinusitis are frequently filled with pus, mucoeceles and polyps, are not reached effectively by systemic antibiotic treatment.

Source and destination memory in face-to-face interaction: A multinomial modeling approach.

Arguing that people are often in doubt concerning to whom they have presented what information, Gopie and MacLeod (2009) introduced a new memory component, destination memory: remembering the destination of output information (i.e., "Who did you tell this to?"). They investigated source (i.e., "Who told you that?") versus destination memory in computer-based imagined interactions. The present study investigated destination memory in real interaction situations. In 2 experiments with mixed-gender (N = 53) versus same-gender (N = 89) groups, source and destination memory were manipulated by creating a setup similar to speed dating. In dyads, participants completed phrase fragments with personal information, taking turns. At recognition, participants decided whether fragments were new or old and, if old, whether they were listened to or spoken and which depicted person was the source or the destination of the information. A multinomial model was used for analyses. Source memory significantly exceeded destination memory, whereas information itself was better remembered in the destination than in the source condition. These findings corroborate the trade-off hypothesis: Context is better remembered in input than in output events, but information itself is better remembered in output than in input events. We discuss the implications of these findings for real-world conversation situations.

Protease-antiprotease imbalances differ between Cystic Fibrosis patients' upper and lower airway secretions.

BACKGROUND: Balanced levels of proteases and anti-proteases are essential in host defense systems. In CF patients' lungs, elevated protease/anti-protease-ratios contribute to damage of airway tissue and premature death with the inherited disease. Little is known about upper airway protease equilibrium in CF. METHODS: Neutrophil elastase (NE), Secretory leukocyte protease inhibitor (SLPI), matrix metalloproteinase (MMP)9, tissue inhibitors of metalloproteinase (TIMP)1, cathepsin S (CTSS) and the corresponding cellular distribution were assessed in the nasal lavage (NL) and sputum of 40 CF patients. RESULTS: Concentrations of all proteases and anti-proteases were markedly higher in sputum than in NL (NE: 10-fold, SLPI: 5000-fold). Interestingly, the NE/SLPI ratio was 726-fold higher in NL compared to sputum, while the MMP9/TIMP1 ratio was 4.5-fold higher in sputum compared to NL. DISCUSSION: This first study to compare protease/anti-protease networks of CF upper and lower airways by NL and sputum reveals substantial differences between both compartments' immunological responses. This finding may have implications for sinonasal and pulmonary treatment, possibly leading to new therapeutic approaches.

Dynamics of soluble and cellular inflammatory markers in nasal lavage obtained from cystic fibrosis patients during intravenous antibiotic treatment.

BACKGROUND: In cystic fibrosis (CF) patients, the upper airways display the same ion channel defect as evident in the lungs, resulting in chronic inflammation and infection. Recognition of the sinonasal area as a site of first and persistent infection with pathogens, such as Pseudomonas aeruginosa, reinforces the "one-airway" hypothesis. Therefore, we assessed the effect of systemic antibiotics against pulmonary pathogens on sinonasal inflammation. METHODS: Nasal lavage fluid (NLF) from 17 CF patients was longitudinally collected prior to and during elective intravenous (i.v.) antibiotic treatment to reduce pathogen burden and resulting inflammation (median treatment time at time of analysis: 6 days). Samples were assessed microbiologically and cytologically. Cytokine and chemokine expression was measured by Cytometric Bead Array and ELISA (interleukin (IL)-1ß, IL-6, IL-8, MPO, MMP9, RANTES and NE). Findings were compared with inflammatory markers from NLF obtained from 52 healthy controls. RESULTS: Initially, the total cell count of the NLF was significantly higher in CF patients than in controls. However after i.v. antibiotic treatment it decreased to a normal level. Compared with controls, detection frequencies and absolute concentrations of MPO, IL-8, IL-6 and IL-1ß were also significantly higher in CF patients. The detection frequency of TNF was also higher. Furthermore, during i.v. therapy sinonasal concentrations of IL-6 decreased significantly (P = 0.0059), while RANTES and MMP9 levels decreased 10-fold and two-fold, respectively. PMN-Elastase, assessed for the first time in NFL, did not change during therapy. CONCLUSIONS: Analysis of NLF inflammatory markers revealed considerable differences between controls and CF patients, with significant changes during systemic i.v. AB treatment within just 6 days. Thus, our data support further investigation into the collection of samples from the epithelial surface of the upper airways by nasal lavage as a potential diagnostic and research tool.

Non-invasive assessment of upper and lower airway infection and inflammation in CF patients.

BACKGROUND: The upper (UAW) and lower (LAW) airways of patients with cystic fibrosis (CF) have the same ion-channel defects, but little is known about similarities and differences in host immunological responses at the two levels. AIM: Identification and comparison of both levels' pathogen colonization and resulting immunological host responses. METHODS: The UAW and LAW of 40 CF patients were non-invasively assessed by nasal lavage and induced sputum. Pathogen colonization, cytology, and the concentrations of inflammatory mediators (TNF-α, MPO, matrix metalloprotease (MMP)-9, tissue inhibitor of metalloprotease (TIMP)-1, regulated upon activation, normal T-cell expressed and presumably secreted (RANTES), and interleukin (IL)-1ß, -5, -6, -8, and -10) were measured. RESULTS: Inflammatory responses were more pronounced in the LAW than the UAW. Pseudomonas aeruginosa LAW colonization is accompanied by a significantly enhanced neutrophil (PMN)-dominated response (P = 0.041) and IL-8 concentration (P = 0.01) not observed in P. aeruginosa UAW colonization. In contrast, sinonasal P. aeruginosa colonization resulted in elevated RANTES (P = 0.039) and reduced MMP-9 (P = 0.023) and TIMP-1 (P = 0.035) concentrations. Interestingly, LAW P. aeruginosa colonization was associated with reduced sinonasal concentrations of MMP-9 (P = 0.01) and TIMP-1 (P = 0.02), a finding independent of UAW colonization for MMP-9. CONCLUSION: CF UAW and LAW show distinct inflammatory profiles and differentiated responses upon P. aeruginosa colonization. Assessment of UAW colonization and MMP-9 are predictive of chronic pulmonary colonization with P. aeruginosa. Thus, this linkage between CF UAW and LAW can provide new clinical and scientific implications.

Influences of nasal lavage collection-, processing- and storage methods on inflammatory markers--evaluation of a method for non-invasive sampling of epithelial lining fluid in cystic fibrosis and other respiratory diseases.

BACKGROUND: Non-invasive sampling of airway epithelial-lining-fluid by nasal lavage (NL) is an emerging method to monitor allergy, infection and inflammation in patients with respiratory diseases. However, the influences of collection-, processing- and storage-methods have not been sufficiently evaluated and standardized. METHODS: Influences of repeated NL, centrifugation setups, repeated freezing and thawing, and protease inhibitors on mediator concentration were evaluated in healthy controls and CF patients, which serve as a model for chronic bacterial infection and inflammation. Polymorphonuclear leukocyte elastase (NE)/myeloperoxidase (MPO)/interleukin (IL)-1/IL-6/IL-8 and tumour necrosis factor alpha (TNF) concentrations were measured using ELISA and Multiplex Bead-Arrays. RESULTS: NL-repetition within 0.5-4h markedly decreased NE, IL-8 and MPO-concentrations for up to 70%. NL centrifugation up to 250×g for cellular differentiation did not significantly influence mediator concentration in native and processed NL fluid. NL freezing and thawing markedly decreased IL-8 and MPO concentrations by up to 50% while NE remained stable. In contrast to preceding reports, storing at -70°C for ≥5 years led to significantly reduced mediator concentrations in NL compared to contemporary analyses, being most pronounced for IL-1ß, IL-6 and TNFa. Storing of samples in the presence of protease inhibitors led to an increase in marker concentration for IL-8 (+27%) and MPO (+15%) even after one year of storage. CONCLUSIONS: NL is an easy and robust technique for inflammation monitoring of the upper airways. For the first time we have shown that diagnostic NL should be performed only once daily to get comparable results. Whereas NL-fluid can be stored unprocessed at -70°C for cytokine analysis over 1-2 years with protease inhibitors supporting stability, ≥5 years storage as well as repeated freezing and thawing should be avoided.