Sleeping Beauty? Developmental Timing, Sleep, and the Circadian Clock in Caenorhabditis elegans.

The genetics toolkit is pretty successful in drilling down into minutiae. The big challenge is to integrate the information from this specialty as well as those of biochemistry, physiology, behavior, and anatomy to explain how fundamental biological processes really work. Sleep, the circadian clock and development all qualify as overarching processes that encompass levels from molecule to behavior as part of their known mechanisms. They overlap each other, such that understanding the mechanisms of one can lead to insights into one of the others. In this essay, we consider how the experimental approaches and findings relating to Caenorhabditis elegans development and lethargus on one hand, and to the circadian clock and sleep in higher organisms on the other, could complement and enhance one another.

[Osteoporosis detection using cone-beam computed tomography]. / Osteoporoseerkennung mittels digitaler Volumentomographie.

BACKGROUND: Osteoporosis is still underdiagnosed in Germany. OBJECTIVES: Is it possible to detect osteoporosis on the basis of a cone-beam computed tomography image of the mandible and several measuring methods? MATERIALS AND METHODS: Sixteen cone-beam computed tomography (CBCT) images from patients of the dental clinic at the University of Ulm were reinvestigated. When the CBCT images were processed the subjects were at least 55 years old, and the mandible was completely mapped on the image. Furthermore, a dual-energy X­ray absorptiometry scan or a CT bone mineral density test was required for every subject. The subjects were divided into an osteoporosis group and a control group. The computed tomography mental index (CTMI), the computed tomography mandibular index superior (CTI[S]) and the computed tomography mandibular index inferior (CTI[I]) were deployed for comparison of the groups. In the first instance a comparison of the osteoporosis and control groups was made for both male and female subjects. Subsequently, only the images of the female subjects were compared to each other. RESULTS: A possibility for osteoporosis can be expressed at CTMI values located < 3.0 mm. As well for CTI(S) < 0.18 and CTI(I) < 0.23. There arises a 66.7 % sensitivity and 70 % specificity for the mixed subject group and an 80 % sensitivity and 57.1 % specificity for the female subject group for CTMI and CTI(S). Furthermore, there are 50.0 % sensitivity and 70 % specificity for the mixed subject group and 60.0 % sensitivity and 57.1 % specificity for the female subject group for the CTI(I). CONCLUSION: CTMI, CTI(S) and CTI(I) are only suitable for osteoporosis detection to a limited extent.

Assessment of apical periodontitis by MRI: a feasibility study.

PURPOSE: The purpose of this clinical feasibility study was to evaluate the applicability of magnetic resonance imaging (MRI) for the assessment of apical periodontitis in direct comparison with cone beam CT (CBCT). MATERIALS AND METHODS: 19 consecutive patients (average age 43 ±â€Š13 years) with 34 lesions in total (13 molars, 14 premolars and 7 front teeth) were enrolled in this feasibility study. Periapical lesions were defined as periapical radiolucencies (CBCT) or structural changes in the spongy bone signal (MRI), which were connected with the apical part of a root and with at least twice the width of the periodontal ligament space. The location and dimension of the lesions were compared between MRI and CBCT. RESULTS: While mainly mineralized tissue components such as teeth and bone were visible with CBCT, complimentary information of the soft tissue components was assessable with MRI. The MRI images provided sufficient diagnostic detail for the assessment of the main structures of interest. Heterogeneous contrast was observed within the lesion, with often a clear enhancement close to the apical foramen and the periodontal gap.  No difference for lesion visibility was observed between MRI and CBCT. The lesion dimensions corresponded well, but were slightly but significantly overestimated with MRI. A heterogeneous lesion appearance was observed in several patients. Four patients presented with a well circumscribed hyperintense signal in the vicinity of the apical foramen. CONCLUSION: The MRI capability of soft tissue characterization may facilitate detailed analysis of periapical lesions. This clinical study confirms the applicability of multi-contrast MRI for the identification of periapical lesions. KEY POINTS: MRI can be applied for the identification of periapical lesions without ionizing radiation exposure. MRI might facilitate more detailed characterization of periapical lesions. MRI might provide more accurate lesion dimensions as X-ray-based methods.

Intraoral radiology in general dental practices - a comparison of digital and film-based X-ray systems with regard to radiation protection and dose reduction.

PURPOSE: The purpose of this study was to gain insight into the distribution and application of digital intraoral radiographic techniques within general dental practices and to compare these with film-based systems in terms of patient dose reduction. MATERIALS AND METHODS: 1100 questionnaires were handed out to general dental practitioners. Data was analyzed with respect to the type of system by using descriptive statistics and nonparametric tests, i.e. Kruskal-Wallis, Mann-Whitney and chi-square test (SPSS 20). RESULTS: 64% of the questioned dentists still use film-based radiology, 23% utilize storage phosphor plate (SPP) systems and 13% use a charge-coupled device (CCD). A strong correlation between the number of dentists working in a practice and the use of digital dental imaging was observed. Almost 3/4 of the film users work with E- or F-speed film. 45% of them refuse to change to a digital system. The use of lead aprons was popular, while only a minority preferred thyroid shields and rectangular collimators. A fourfold reduction of exposure time from D-speed film to CCD systems was observed. Due to detector size and positioning errors, users of CCD systems take significantly more single-tooth radiographs in total. Considering the number of radiographs per patient, there is only a slight tendency towards more X-rays with CCD systems. Up to image generation, digital systems seem to be as or even more difficult to handle than film-based systems, while their handling was favored after radiographic exposure. CONCLUSION: Despite a slight increase of radiographs taken with CCD systems, there is a significant dosage reduction. Corresponding to the decrease in exposure time, the patient dose for SPP systems is reduced to one half compared to film. The main issues in CCD technology are positioning errors and the size of the X-ray detectors which are difficult to eliminate. The usage of radiation protection measures still needs to be improved. KEY POINTS: ► Responsible use of digital intraoral radiology results in a significant dose reduction in everyday practice. ► The ALARA principle is only achieved by strict implementation of dose-reducing methods. ► The efforts to use dose-reducing devices must be increased.

Assessment of the effective doses from two dental cone beam CT devices.

OBJECTIVES: This study compares the effective dose for different fields of view (FOVs), resolutions and X-ray parameters from two cone beam CT units: the KaVo 3D (three-dimensional) eXam and the KaVo Pan eXam Plus 3D (KaVo Dental, Biberach, Germany). METHODS: Measurements were made using thermoluminescent dosemeter chips in a radiation analog dosimetry head and neck phantom. The calculations of effective doses are based on the ICRP 60 and ICRP 103 recommendations of the International Commission on Radiological Protection. RESULTS: Effective doses from the 3D eXam ranged between 32.8 µSv and 169.8 µSv, and for the Pan eXam Plus effective doses ranged between 40.2 µSv and 183.7 µSv; these were measured using ICRP 103 weighting factors in each case. The increase in effective dose between ICRP 60 and ICRP 103 recommendations averaged 157% for all measurements. CONCLUSIONS: Effective doses can be reduced significantly with the choice of lower resolutions and mAs settings as well as smaller FOVs to avoid tissues sensitive to radiation being inside the direct beam. Larger FOVs do not necessarily lead to higher effective doses.

Ultrashort echo time (UTE) MRI for the assessment of caries lesions.

OBJECTIVE: Direct in vivo MRI of dental hard tissues by applying ultrashort echo time (UTE) MRI techniques has recently been reported. The objective of the presented study is to clinically evaluate the applicability of UTE MRI for the identification of caries lesions. METHODS: 40 randomly selected patients (mean age 41 ± 15 years) were enrolled in this study. 39 patients underwent a conventional clinical assessment, dental bitewing X-ray and a dental MRI investigation comprising a conventional turbo-spin echo (TSE) and a dedicated UTE scan. One patient had to be excluded owing to claustrophobia. In four patients, the clinical treatment of the lesions was documented by intraoral pictures, and the resulting volume of the cavity after excavation was documented by dental imprints and compared with the MRI findings. RESULTS: In total, 161 lesions were identified. 157 (97%) were visible in the UTE images, 27 (17%) in the conventional TSE images and 137 (85%) in the X-ray images. In total, 14 teeth could not be analysed by MR owing to artefacts caused by dental fillings. All lesions appear significantly larger in the UTE images as compared with the X-ray and TSE images. In situ measurements confirm the accuracy of the lesion dimensions as observed in the UTE images. CONCLUSION: The presented data provide evidence that UTE MR imaging can be applied for the identification of caries lesions. Although the current data suggest an even higher sensitivity of UTE MRI, some limitations must be expected from dental fillings.

Quality assurance in digital dental radiography--justification and dose reduction in dental and maxillofacial radiology.

OBJECTIVE: To evaluate the implementation of quality assurance requirements for digital dental radiography in routine clinical practice. The results should be discussed by radiation protection authorities in the context of the relevant legal requirements and current debates on radiation protection. MATERIALS AND METHODS: Two hundred digital dental radiographs were randomly selected from the digital database of the Department of Dentistry's Dental and Maxillofacial Surgery Clinic, Ulm University, and evaluated for various aspects of image quality and compliance with radiographic documentation requirements. The dental films were prepared by different radiology assistants (RAs) using one of two digital intraoral radiographic systems: Sirona Heliodent DS, 60 kV, focal spot size: 0.7 mm (group A) or KaVo Gendex 765 DC, 65 kV, focal spot size: 0.4 mm (group B). RESULTS: Radiographic justification was documented in 70.5% of cases, and the radiographic findings in 76.5%. Both variables were documented in the patient records as well as in the software in 14% of cases. Clinical documentation of the required information (name of the responsible dentist and radiology assistant, date, patient name, department, tube voltage, tube current, exposure time, type of radiograph, film size, department and serial number of the dental radiograph) was 100% complete in all cases. Moreover, the department certified according to DIN ISO 9001:2008 specifications demonstrated complete clinical documentation of radiographic justifications and radiographic findings. The entire dentition was visible on 83% of the digital films. The visible area corresponded to the target region on 85.7% of the digital dental radiographs. Seven to 8.5% of the images were classified as "hypometric" or "hypermetric". CONCLUSIONS: This study indicates that improvements in radiology training and continuing education fordentists and dental staff performing x-ray examinations are needed to ensure consistent high quality of digital dental radiography. Implementation of internal radiological quality assurance programs, as required by public law in Germany since 2010 (SGB V), would appear prudent.

Comparison of cone beam computed tomography scans with and without simulation of head motion.

PURPOSE: To test for differences in image quality between 3D volumetric datasets acquired by cone beam computed tomography (CBCT) with and without simulation of head motion by visual analysis of individual image sections and by comparison of scan-based distance and Hounsfield unit (HU) measurements. MATERIALS AND METHODS: A total of 200 volumetric datasets were acquired with and without remote-controlled, simulated movement of a human cadaver head using the KaVo 3D eXam CBCT system. RESULTS: The "Landscape 8 x 8 cm Slide" mode provided a sufficient field of view at a low radiation dose. All datasets showed reproducible results. Our analysis showed that the level of image quality and image detail increased with increasing resolution. Linear distance measurements and HU measurements in the cone beam CT scans acquired without simulation of head motion were absolutely comparable to those obtained with head motion simulation. CONCLUSIONS: There is no practical difference in image quality between CBCT scans acquired with and without head motion if no long-term change in head position occurs during the acquisition process. Slight head movement has no clinically relevant effect on the geometric accuracy or visual image quality of cone beam CT scans.

Antibiotic resistance testing of the total implant-associated micro-flora and its pure isolates.

OBJECTIVE: The aim of the present study was to examine antibiotic resistant strains among the implant-associated microorganisms in vitro, first as mixed cultures and again as pure isolates for resistance to one of five antibiotics. METHODS: Samples were taken with sterile paper points from the deepest pocket of one implant per patient (n = 24) to culture the total oral micro-flora. The samples were streaked on agar (Schaedler or BHI) and incubated for 7 d in an anaerobic atmosphere. All colonies were rinsed off the plates, aliquots were added to top-agar. Susceptibility against antibiotics (ampicillin, ampicillin + sulbactam, azithromycin and penicillin, moxifloxacin) was determined using the Etest. Resistant strains were picked, purified and characterized, and the Etests were repeated with a selection of the pure isolates. RESULT: The majority of the mixed cultures (67 - 100 %) showed complete antibiotic resistance. No association with clinical parameters like pocket depth, bleeding on probing or insertion of implants into transplanted bone could be found. Smoking and the surface of the implant also had no influence. 23 % of the 597 resistant colonies contained only yeasts, mostly isolated from irradiated tumour patients. Of the 458 resistant bacteria, the majority were Gram-positive cocci or rods. Staphylococci and M. micros were detected occasionally. The resistance for the 138 selected pure isolates was in most cases lower than for the total micro-flora, irrespective of the antibiotic. CONCLUSIONS: The higher resistance of the total flora might be explained by synergistic interactions between its members.

Development of a new micro-endoscope for odontological application.

PURPOSE: Development and introduction of a new micro-endoscope called Visio Scope for multidiscipline use in dentistry. METHODS: During the development of the new micro-endoscope called Visio Scope testings in the following dental disciplines were performed: endodontics, periodontology, implantology, periapical surgery, prosthodontics, and laser treatment. In this first report, flexible micro-endoscopes with an external diameter of 1.0 mm as well as of 0.34 mm were used. RESULTS: There is a significant improvement in all tested disciplines concerning handling and flexibility, verification of radiologically not detectable findings. In this context, the endoscope has proved itself clearly superior to conventional optical aids, above all the surgical microscope. The working canal facilitates specific application of medication and irrigation solutions. CONCLUSIONS: The Visio Scope allows visual control of the extent of the bone defect and enables optical control after removal of concrements and granulation tissue, before possible regenerative measures. Root fractures and furcation invasion can be reliably documented. Optical control guarantees preoperative and postoperative success of treatment.

Quantitative and qualitative differences in morphological traits revealed between diploid Fragaria species.

BACKGROUND AND AIMS: The aims of this investigation were to highlight the qualitative and quantitative diversity apparent between nine diploid Fragaria species and produce interspecific populations segregating for a large number of morphological characters suitable for quantitative trait loci analysis. METHODS: A qualitative comparison of eight described diploid Fragaria species was performed and measurements were taken of 23 morphological traits from 19 accessions including eight described species and one previously undescribed species. A principal components analysis was performed on 14 mathematically unrelated traits from these accessions, which partitioned the species accessions into distinct morphological groups. Interspecific crosses were performed with accessions of species that displayed significant quantitative divergence and, from these, populations that should segregate for a range of quantitative traits were raised. KEY RESULTS: Significant differences between species were observed for all 23 morphological traits quantified and three distinct groups of species accessions were observed after the principal components analysis. Interspecific crosses were performed between these groups, and F2 and backcross populations were raised that should segregate for a range of morphological characters. In addition, the study highlighted a number of distinctive morphological characters in many of the species studied. CONCLUSIONS: Diploid Fragaria species are morphologically diverse, yet remain highly interfertile, making the group an ideal model for the study of the genetic basis of phenotypic differences between species through map-based investigation using quantitative trait loci. The segregating interspecific populations raised will be ideal for such investigations and could also provide insights into the nature and extent of genome evolution within this group.

[Scintigraphic demonstration of aspiration in long-term ventilation patients with tracheotomy]. / Szintigraphischer Nachweis der Aspiration bei langzeitbeatmeten Patienten mit Tracheotomie.

The main complication of enteral feeding in prolonged mechanical ventilation via tracheostomy is the subsequent aspiration pneumonia. We used a scintigraphic method for the detection of enteral feeding aspiration and compared the results with clinical evidence of aspiration. The study population consisted of 62 consecutive tracheotomised patients (16 females, age: 64.1 +/- 11.1 years). The swallowing test was done in an upright or semirecumbent body position with the patients spontaneously breathing. The standard feed consisted of a liquid, semiliquid and solid meal which was labelled by 100 MBQ 99 TC. Scintigraphic aspiration (SA) was defined as positive if radioactivity was detected in the bronchial system. Clinical aspiration (CA) was defined as positive if there was cough, choking and distress after swallowing; furthermore, when receiving enteral feeding during suctioning or bronchoscopy. Both clinically significant aspiration (CA) and scintigraphic aspiration (SA) were found to be identical in 10 of 62 (16%) patients. CA, but not SA: 4/62 (6.5%). SA, but not CA (Subclinical aspiration): 4/62 (6.5%). Nor CA neither SA: 44/62 (71%) patients. Radiolabelled feed can be used as a feasible marker to detect aspiration. The test is a useful screening test and strategy to minimize aspiration. The scintigraphic method failed to identify all tracheotomised patients with clinically significant aspiration. However, scintiscanning did suggest that some patients had subclinical aspiration.

[Daytime mechanical ventilation in chronic ventilatory insufficiency]. / Nichtinvasive Beatmung am Tag bei Patienten mit chronisch ventilatorischer Insuffizienz.

BACKGROUND: Nocturnal hypoventilation is associated with chronic ventilatory insufficiency (CVI). Noninvasive mechanical ventilation (NIV) performed overnight relieves symptoms of hypoventilation and improves daytime blood gases in CVI. In order to test whether the efficacy of NIV depends on its being applied during sleep we conducted a prospective case controlled study comparing daytime mechanical ventilation (DV) in awake patients with nocturnal mechanical ventilation (NV) given in equal quantities. PATIENTS AND METHODS: We enrolled 34 clinically stable patients (age: 56.1 +/- 12.1 years, 20 female) with CVI due to both restrictive lung and chest wall disorders and neuromuscular disease. Using a prospective case-control design, matched subjects were allocated alternately to DV and NV. RESULTS AND CONCLUSIONS: There were no significant differences between the groups in the improvement of the measured parameters; (e.g. PaCO2; DV: from 57.6 +/- 4.3 to 44.0 +/- 4.6 mm Hg, NV: from 55.5 +/- 3.5 to 45.0 +/- 4.1 mm Hg, p < 0.0001). We conclude that in many respects, when compared to NV, DV in awake patients is equally effective for the treatment of CVI.

Blood transfusion and lung function in chronically anemic patients with severe chronic obstructive pulmonary disease.

OBJECTIVE: To study in anemic patients with chronic obstructive pulmonary disease (COPD) whether blood transfusion reduces minute ventilation and work of breathing (WOB). DESIGN: We prospectively evaluated the minute ventilation and WOB in 20 anemic adults (hemoglobin of <11 g/dL). Ten patients had severe COPD and ten patients were without lung disease. Measurements were made before and after receiving red blood cell transfusion; post-transfusion measurements were made 24 to 36 hrs after the last transfusion. SETTING: The study was performed in the intensive care unit of a tertiary referral center for home mechanical ventilation and for patients considered difficult to wean from mechanical ventilation. PATIENTS: Twenty clinically stable patients (12 female, eight male) with chronic anemia were studied. Ten patients with COPD (mean forced expiratory volume in 1 sec: 0.55+/-0.1 [SD] L) were compared with ten patients without lung disease. All participants had adequate renal and left ventricular function. INTERVENTIONS: Patients received 1 unit of packed red blood cells for each g/dL that their hemoglobin value was less than an arbitrarily defined target value of 11.0 to 12.0 g/dL. Each unit was transfused over 2 hrs and < or =3 units in total was given. MEASUREMENTS AND MAIN RESULTS: Esophageal pressure was measured from a catheter which was positioned in the middle of the esophagus. Flow was measured using a pneumotachygraph connected to a mouthpiece while a nose clip closed the nostrils during the measurements. From these data, respiratory rate, minute ventilation, and inspiratory resistive WOB were computed. Arterial blood gas values, oxygen saturation, hemoglobin, and hematocrit were also measured, and oxygen content was calculated before and 24 to 36 hrs after transfusion. In patients with COPD, hemoglobin increased from 9.8+/-0.8 to 12.3+/-1.1 g/dL due to a mean transfusion of 2.2+/-0.4 (SD) units of red blood cells. There was a reduction in the mean minute ventilation from 9.9+/-1.0 to 8.2+/-1.2 L/min (p < .0001); correspondingly, WOB decreased from 1.03+/-0.24 to 0.85+/-0.21 WOB/L (p< .0001). The capillary P(CO2) increased from 38.1+/-6.0 to 40.7+/-6.8 torr (5.1+/-0.8 to 5.8+/-0.9 kPa) (p < .05). Similarly, capillary P(O2) changed from 56.9+/-8.9 to 52.8+/-7.0 torr (7.6+/-1.2 to 7.0+/-0.9 kPa) (p < .05). In anemic patients without lung disease, minute ventilation, WOB, and the capillary blood gas values did not change after increase of the hemoglobin by a similar degree. CONCLUSIONS: We conclude that red blood cell transfusion in anemic patients with COPD leads to a significant reduction of both the minute ventilation and the WOB. In these patients, transfusion may be associated with unloading of the respiratory muscles, but it may also result in mild hypoventilation.

[Predictive value of laryngoscopy with reference to the severity of obstructive sleep apnea]. / Prädiktiver Wert der Laryngoskopie hinsichtlich des Schweregrades schlafbezogener obstruktiver Atemstörungen.

The diagnosis of sleep-related breathing disorders is based primarily upon targeted history-taking and upon night-time polysomnography. Diagnostic measures should be completed by laryngopharyngoscopy (LPS). Frequently in cases of relevant obstructive sleep-related breathing disorders, a collapse of the pharyngeal lumen may be detected already in the waking state: either during spontaneous breathing or through adequate provocation (snoring manoeuvre). Furthermore, endoscopy of the upper airways will yield indirect clues as to nocturnal snoring and possible obstructive apnoeas. Although the predictive value of LPS regarding the degree of obstructive sleep-related breathing disorders seems low compared with polysomnography, it appears reasonable to perform it to exclude further relevant ENT findings. With LPS, local and regional obstacles of the kind of the intended positive pressure ventilation (narrowing of the nasal ducts, septum deviation and hyperplasia of the turbinates) are demonstrable which may warrant surgical correction. LPS, which has a low complication rate, facilitates interdisciplinary cooperation in the care for patients suffering from obstructive sleep-related breathing disorders.

[Anemia increases work of breathing in patients with lung disease]. / Anämie steigert die Atemarbeit bei Patienten mit Lungenerkrankung.

BACKGROUND: Pulmonary diseases with marked disorders in gas exchange or chronic overload of the respiratory pump needs increased ventilatory requirements. Additionally in these patients anemic may aggravate the ventilatory load. We thereby evaluated whether in these patients treatment of anemia (red blood cell transfusion: RBCT) leads to an improvement of the ventilatory load in comparison to the anemic patients without pulmonary disease. PATIENTS AND METHODS: We examined 21 patients with an anemia (Hb < 11 g%, 12 men). Fifteen patients had a pulmonary disease (group A), 6 patients suffered from anemia without pulmonary disease (group B). Subsequently within 8 hours the patients got 2 to 3 RBCT. We studied the patients on the day of admission and 24 to 36 hours after transfusion. The patients kept bed rest for spontaneous breathing 1 hour prior to the actual examination without supplemental oxygen. Hemoglobin, hematocrit, respiratory rate, respiratory minute volume and arterial blood gases were measured. On the following day we repeated the same procedures. RESULTS AND CONCLUSIONS: Anemia in patients with an increased ventilatory requirement causes an additional increase of work of breathing. In these patients-in contrast to patients without compromised lungs-2.2 red blood cell transfusions lead to an impressive reduction of VE (about 20%) and correspondingly also to a reduction of WOB.

[Increased physical activity due to intermittent self-ventilation in chronic respiratory insufficiency]. / Zunahme der körperlichen Aktivität infolge intermittierender Selbstbeatmung bei chronisch ventilatorischer Insuffizienz.

BACKGROUND: Nocturnal mechanical ventilation (NMV) can reduce symptoms of hypoventilation and improve gas exchange in patients with chronic respiratory failure but there is no data concerning the impact of nocturnal mechanical ventilation on daily activity. We prospectively measured daily activity as judged by total steps per day. PATIENTS AND METHODS: Thirty stable patients (17 men, mean age 55.2 years, pCO2: 62.3 +/- 9.0 mmHg) with chronic respiratory failure. DIAGNOSIS: Kyphoscoliosis (n = 11), COLD (n = 7), neuromuscular diseases (n = 6), post-tbc sequelae (n = 6). Applying a pedometer over a 7 day period before and 3 months after initiating nocturnal mechanical ventilation the steps per day were counted. We also obtained arterial blood gases and applied the St. George's Respiratory Questionnaire (scoring range from 0 = complete health to 100 = worst possible). RESULTS AND CONCLUSIONS: The daily activity in patients with hypercapnic respiratory failure as judged by the total amount of steps per day increased by 120% after 3 months of nocturnal mechanical ventilation (from 1606.9 +/- 1341.3 to 3535 +/- 1813.8 steps per day, p < 0.0001). This was associated with a significant improvement in daytime blood gases and quality of life (QoL) as judged by questionnaire (total score: from 61.3 +/- 14.9 to 48.3 +/- 18.7, p = 0.0006). However no correlation between steps per day and QoL was found.

Endoscopic placement of a tracheal oxygen catheter: a new technique.

OBJECTIVE: In patients with chronic obstructive pulmonary disease (COPD), intratracheal oxygen insufflation (ITO) is an established therapeutic approach. We developed a new endoscopic technique of intratracheal catheter placement. The aim of this pilot study was to demonstrate its short-term feasibility in acutely extubated patients with moderate to severe COPD who require oxygen therapy. DESIGN: A guide wire was inserted through a nasally passed bronchoscope and was positioned such that its tip was placed intratracheally. Using a "Seldinger technique", the tracheal catheter was then inserted over the wire to a point 2-3 cm proximal to the carina and positioned under direct vision from the bronchoscope inserted through the contralateral nose. After catheter insertion, the guide wire was removed. The patients scored catheter-associated local discomfort using a visual analogue scale. In a randomly assigned, crossover design, the effectiveness of the endoscopically (e) inserted ITO catheter was assessed by measuring the capillary blood gases, respiratory rate (RR), tidal volume (Vt) and minute ventilation (MV) after 1 h breathing room air without eITO and 1 h after eITO (flow: 3 l/min). MEASUREMENTS AND RESULTS: The eITO catheter was placed in all patients without complications and with only minimal discomfort in two patients (spontaneously reversible cough). Compared to breathing room air, capillary O2 pressure increased (from 54.7 +/- 9.4 to 82.8 +/- 21.8 mmHg) whereas Vt (from 458.7 +/- 86.8 to 358.3 +/- 75.1 ml) and MV (from 7.7 +/- 1.5 to 5.5 +/- 1.1 l/ min) decreased significantly (each p < 0.0001) with eITO in all patients. The capillary CO2 pressure and RR did not change. CONCLUSIONS: Acutely extubated patients in whom oxygen therapy is indicated may profit from eITO. This new technique works immediately and is thus an effective short-term intervention of potential value in the intensive care unit.

Evaluation of a movement detector to measure daily activity in patients with chronic lung disease.

This study was designed to evaluate the performance of movement detectors (pedometers) in measuring daily activity of patients with chronic lung disease. Three groups of subjects were studied: group 1: 25 patients with stable nonhypercapnic chronic obstructive pulmonary disease (COPD) (forced expiratory volume in one second (FEV1) = 47+/-9% predicted) studied twice, one month apart; group 2: 25 patients with chronic respiratory failure studied before and three months after nasal nocturnal mechanical ventilation; and group 3: 25 normal healthy subjects studied once. The median level of activity in the healthy subjects (group 3) was three times greater than in either group of patients (groups 1 and 2). Activity levels were not correlated with age, sex or employment status. The repeatability of the activity counts in the nonhypercapnic COPD patients was high (intraclass correlation coefficient=0.94) and in these patients activity correlated significantly with FEV1 (r=0.54, p=0.006). In the respiratory failure patients, daytime arterial carbon dioxide pressure (Pa,CO2) improved following nasal nocturnal mechanical ventilation (NMV) (pre NMV: 8.5+/-1.2 kPa; post NMV: 6.2+/-0.5 kPa), health status improved (p<0.004) and daily movement count doubled (p<0.0001). This increase correlated with change in Pa,CO2 (r-0.53, p=0.006), but not with improved health status. We conclude that motion detectors may provide repeatable measures of daily activity that are related to physiological impairment and improvement following treatment. Activity counts appear to be complementary to estimates of exercise limitation obtained using health questionnaires.

Daytime mechanical ventilation in chronic respiratory insufficiency.

Chronic respiratory insufficiency (CRI) is associated with nocturnal hypoventilation. Treatment with noninvasive mechanical ventilation (NIMV) performed overnight relieves symptoms of hypoventilation and improves daytime blood gases in CRI. In order to test whether the efficacy of NIMV depends on it being applied during sleep, we conducted a prospective case-controlled study comparing daytime mechanical ventilation (dMV) in awake patients with nocturnal mechanical ventilation (nMV) given in equal quantities. We enrolled 34 clinically stable patients (age 56.1+/-12.1 yrs, 20 females, 14 males) with CRI due to restrictive lung and chest wall disorders and neuromuscular disease. Using a prospective case-control design, matched subjects were allocated alternately to dMV and nMV. After 1 month of NIMV there was considerable symptomatic improvement in both dMV and nMV patients. There were no significant differences between groups in the improvement in daytime arterial carbon dioxide tension (Pa,CO2) (dMV from 7.5+/-0.6 to 5.7+/-0.6 kPa; nMV from 7.2+/-0.5 to 5.8+/-0.5 kPa, p<0.0001) and during the unassisted spontaneous night-time ventilation in terms of transcutaneous Pa,CO2 (dMV from 8.4+/-1.2 to 6.6+/-0.7 kPa; nMV from 8.2+/-1.2 to 6.8+/-0.5 kPa, p<0.0001). We conclude that in many respects, when compared to nocturnal mechanical ventilation, daytime mechanical ventilation in awake patients is equally effective at reversing chronic respiratory insufficiency. Since long-term safety issues were not addressed in this study, we recommend that nocturnal mechanical ventilation should remain the modality of choice for noninvasive mechanical ventilation.