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Biomedical subjects

P G Djupesland

Publications and source records attributed to P G Djupesland.

At least 19 recordsLinked to original sources
PubMed2001

Gas and dust exposure in underground construction is associated with signs of airway inflammation.

Exposure to gases and dust may induce airway inflammation. It was hypothesized that heavy construction workers who had been exposed to dust and gases in underground construction work for 1 yr, would have early signs of upper and lower airway inflammation, as compared to outdoor workers. A study group comprising 29 nonsmoking underground concrete workers (mean +/- SD age 44+/-12 yrs), and a reference group of 26 outdoor concrete workers (39+/-12 yrs) were examined by acoustic rhinometry, nasal and exhaled nitric oxide spirometry and a questionnaire on respiratory symptoms. Exposure measurements were carried out. The underground workers had higher exposure to total and respirable dust, alpha-quartz and nitrogen dioxide than the references (p<0.001). The occurrence of respiratory symptoms was higher in the underground workers than in the references (p<0.05). Exhaled nitric oxide (NO) (geometric mean+/-SEM) was higher in the underground workers than in the references (8.4+/-1.09 versus 5.6+/-1.07 parts per billion (ppb), p = 0.001), whereas spirometric values were comparable. The underground workers had smaller nasal cross-sectional area and volume than the references, and more pronounced increases after decongestion (p<0.001). To conclude the exposure in underground construction may cause nasal mucosal swelling and increased levels of exhaled nitric oxide, indicating signs of upper and lower airway inflammation.

Airway Obstruction↗
PubMed2001

A new method for the remote collection of nasal and exhaled nitric oxide.

STUDY OBJECTIVES: The present study introduces a method that has been developed to improve the remote collection and transportation of gas samples from the nose and lungs. DESIGN: Assessment of agreement between two methods of clinical measurements. SETTING: Noninvasive exhaled gas measurement at a respiratory research laboratory. PARTICIPANTS: Ten nonsmoking adult volunteers (median age, 44 years; age range, 33 to 53 years; men, 6; women, 4) were recruited. MEASUREMENTS AND RESULTS: Exhaled nitric oxide (ENO) and nasal nitric oxide (NNO) outputs were measured directly (on-line) and remotely (off-line). With the velum closed, lung air was exhaled at fixed flows (ie, 6, 8, and 10 L/min) (ENO) or room-air was aspirated through the nose in series at one fixed flow (ie, 5 to 8 L/min) (NNO). The off-line nitric oxide (NO) measurements were achieved by a gas collection tube system, which consisted of a flow control unit, a tube reservoir with one-way valves at both ends, and an interrupter valve allowing the trapping of gas inside the tube and eliminating the inclusion of "dead space." After clamping, the reservoir may store and transport the gas samples for delayed analysis. The coefficient of variation of three consecutive NO measurements was < 3% for both on-line and off-line ENO and NNO. The correlations between on-line and off-line measurements in both ENO and NNO outputs were high (r = 0.99; R(2) = 0.99), and, unlike previous studies using bag-collection, the ENO outputs for on-line and off-line measurements were in good agreement (Bland-Altman test) at all flows tested. CONCLUSIONS: The tube gas collection system eliminates the dead space and contamination during the gas sampling and permits the cost-effective and reliable off-line collection of both nasal and exhaled gas samples.

Adult↗
PubMed2001

Accuracy of acoustic rhinometry.

OBJECTIVES: The objective of this study was to evaluate the ability of acoustic rhinometry (AR) (Rhin2100, Rhinometrics, Lynge, Denmark) to accurately determine the dimensions (cross-sectional areas and volumes) of the curved and complex slit-like geometry of the nasal airway. MATERIALS AND METHODS: A plastic model representing the replicate of a decongested nasal airway was produced by stereolithographic techniques from a 3-D MRI-scan. The exact dimensions of this model was determined from a high resolution CT-scan. Dimensions perpendicular to the curved course of the acoustic pathway were compared with dimensions inferred from parallel sections. The impact of sound loss to the paranasal sinuses and the ability to detect posterior volume changes was tested in the same model. RESULTS: The error in volume determination was < 14% for the MCA and < 8% for the volumes, whereas the error reached 52% for dimensions calculated from parallel sections in the coronal plane. The influence of the simulated maxillary sinuses depend primarily on the size of the ostia and may represent an important source of error for posterior measurements, in particular after decongestion. CONCLUSIONS: The accuracy of acoustically derived dimensions of the 3-D model depend on the orientation of the planes used to calculate the dimensions of the model. Volume estimates based on the smallest cross-sectional areas in points along the acoustic pathway correlate well with acoustically derived volumes, whereas single cross-sectional areas are more susceptible to error. Sound leakage to patent sinus ostia reduce the accuracy of posterior measurements.

Acoustics↗
PubMed2000

Computational simulation of accumulation of expired air in the infant cot.

Accumulation and re-breathing of CO2 in expired air has been suggested as one possible explanation for the strong association between prone sleeping position and sudden infant death syndrome (SIDS). This preliminary study applying a modern computational fluid dynamics (CFD) program to simulate the aerodynamics in an infant cot supports the idea that accumulation of expired air may occur in the prone position. The literature dealing with the potential association between re-breathing of accumulated CO2 and SIDS is briefly reviewed.

Air↗
PubMed2000

Necrotizing fascitis of the head and neck--report of three cases and review of the literature.

Necrotizing fasciitis (NF) of the head and neck is a rare but potentially life-threatening soft tissue infection primarily affecting the superficial fascial planes. It is caused by group A streptococci or by a synergistic combination of aerobe and anaerobe micro-organisms. If proper treatment is delayed, the infection may cause extensive necrosis of overlying skin, extend to deeper planes and produce severe systemic toxicity. Recent reviews suggest that cervical and facial NF should be considered separate clinical entities with different clinical features and prognosis. In both, early diagnosis with prompt, aggressive surgical and medical treatment is essential to a successful outcome. Three cases of NF of the neck secondary to peritonsillar/parapharyngeal infections are presented and the main characteristics of 117 well-characterized cases of cervical and facial NF are reviewed.

Adult↗
PubMed2000

Unilateral nasal nitric oxide measurement after nasal surgery.

This study was designed to validate and standardize a method for unilateral nasal nitric oxide (NO) measurement. Fourteen healthy volunteers and 11 patients who had undergone unilateral medial maxillectomy were enrolled. Nasal NO was measured unilaterally by means of a dual pump system, and bilateral nasal NO was measured by aspirating air through the nasal airway in series. The median unilateral NO output was 195 nL/min on the surgical side and 291 nL/min on the contralateral, surgically untreated side (p = .006). The NO output was not significantly different between nostrils in the control group (p = .82). With the bilateral technique, there was no significant difference between the surgery group and the healthy-subjects group (p = .72). The unilateral nasal NO technique is sensitive in determining unilateral differences in nasal NO production. The NO outputs from the nostrils were similar in normal subjects regardless of the nasal cycle, but were significantly lower on the operated side in the unilateral nasal surgery group.

Adult↗
PubMed1999

[Nitric oxide in the nose and paranasal sinuses--respiratory tract physiology in a new perspective].

Nitric oxide (NO) has important functions in a variety of physiological and pathophysiological processes in the body, including vasoregulation, haemostasis, neurotransmission, immunity and respiration. The discovery of surprisingly high concentrations of NO in the nasal airway and paranasal sinuses has important implications for the understanding of airway physiology. The high NO levels in the nasal and paranasal airways contribute to the first line defence against microorganisms. Furthermore, autoinhalation of nasal NO may improve pulmonary function and other remote physiological processes. This airborne messenger system represents a new physiological concept of potential clinical importance. However, NO, like several other mediators, has a dualistic function. Airway NO levels are increased in airway inflammations, such as asthma and allergic rhinitis, but is reduced in cystic fibrosis and other conditions with ciliary dysfunction, sinusitis and after exposure to tobacco and alcohol. Consequently, NO may prove valuable as a non-invasive marker in the diagnosis and monitoring of airway pathologies.

Humans↗
PubMed1999

Aerodynamic influences on nasal nitric oxide output measurements.

Nitric oxide (NO) concentration in aspirated nasal air is flow-dependent. Nasal NO outputs calculated from steady-state plateaux at flows < 1 l/min are substantially smaller than those at flows > 2 l/min. This study aimed to determine the differences in NO output as calculated from the NO concentration plateaux in aspirated nasal air, resulting from different aspiration flows. Nasal NO was determined by chemiluminescent analysis of air obtained from the nasal passages in series during velopharyngeal closure in 8 healthy adults (flows: 0.2-3.7 l/min) and 5 with symptomatic allergic rhinitis (flows: 0.2-3.7 l/min). Mean NO output in the healthy subjects was stable at approximately 315 nl/l/min at flows of 0.2-0.7 l/min, and increased to a second steady output level of approximately 400 nl/l/min (+28%, p < 0.0001) at more physiological flow rates of 2.7 l/min and higher. The symptomatic subjects had substantially higher NO output at all flows (p < 0.001) (709.3 nl/min at 3.7 l/min) than the non-allergic subjects. The flow dependency of the nasal NO output may be explained by failure at low flows for the air stream to penetrate the peripheral parts of the complex nasal passages, and by the presence of a laminar flow regime in which a marginal lamina would tend to insulate the main stream from the mucosa. Thus, previously reported NO outputs obtained at low flows may underestimate nasal NO output compared to output at higher and more physiological transnasal airflow rates, thus affecting interpretation of results.

Adult↗
PubMed1999

Aspiration flow optimized for nasal nitric oxide measurement.

The aim of the present study was to evaluate some of the factors which may influence the reliability of nasal NO measurements, and to optimize methods suitable for children and adults. Nasal nitric oxide (NO) output was determined by chemiluminescent analysis of aspirated samples in 16 adults and 6 children. With the velopharyngeal aperture closed, stable NO levels were obtained at flows ranging form 0.9 to 6.2 L/min. NO output averaged 401.0 +/- 145.4 nL/min./M2 in 6 children, 338.2 +/- 92.3 in 7 adult females and 268.6 +/- 70.2 in 9 adult males. Nasal NO output was independent of flow provided a stable plateau of NO value was reached. In this study, the optimal range of flows was 3.2-5.2 L/min. in adults and 2.2-3.2 L/min. in children. This enables selection of the most favorable flow to be chosen for individual subjects and situations.

Adult↗
PubMed1999

Does nasal nitric oxide come from the sinuses?

OBJECTIVE: The purpose of this study was to assess nitric oxide (NO) output by the nose and sinuses. METHOD: In one volunteer, the osteomeatal complex and sphenoethmoidal recess were occluded to isolate the nose from the sinuses. The antrum and frontal sinus were each punctured by two catheters and irrigated with air at constant flow. Nitric oxide output and its rate of accumulation in the absence of air flow were measured in each sinus and in the adjacent nasal cavity. RESULTS: Prior to ostial occlusion, NO output in the nose was 96 nL/min. It decreased by 12% after blockage of all of the ostia. In the isolated sinuses, it was 190 nL/min (antrum) and 68 nL/min (frontal). After 5 minutes stagnation; NO concentration [NO] rose in the occluded sinuses to 24,700 nL/L in the antrum and 22,300 nL/L in the frontal sinus. In the nose, it increased to 29,000 nL/L. When the period of stagnation was prolonged in the frontal sinus, the [NO] reached a plateau. NO output and accumulation were not altered in the nose or either sinus by opening their ostia. In the antrum and frontal sinus, lidocaine reduced NO output and the rate of NO accumulation, but not in the nose. CONCLUSIONS: In this volunteer, 88% of nasal NO was derived from the nose itself. Nitric oxide exchange between the frontal sinus, antrum, and nose was negligible. In the absence of air flow, [NO] rose to a plateau in the nose and frontal sinus. Lidocaine inhibited NO output in the sinuses but not the nose.

Humans↗
PubMed1998

Nasal airway dimensions and lung function in awake, healthy neonates.

Possible relations between nasal airway dimensions and measures of lung function are not well established. It has been suggested that a major part of airway resistance is found in the nose. However, little is known about the shape of tidal flow volume (TFV) loops in relation to nasal caliber. We therefore investigated whether lung function assessed by tidal breathing in healthy newborn infants was affected by nasal airway dimensions. Nasal airway dimensions were measured in 17 healthy newborn babies (mean age, 2.7 days) by acoustic rhinometry before and immediately after lung function measurements. Lung function was evaluated by TFV loops and passive respiratory mechanics (single-breath occlusion technique), first with both nostrils open, and subsequently immediately after occlusion of the larger of the two nostrils, causing at least a 50% reduction in nasal minimum cross-sectional area (MCA). Neither the TFV expiratory ratios (time and volume to reach peak flow to total time and volume, respectively [t(PTEF)/t(E) and V(PTEF)/V(E), respectively]), nor resistance or compliance of the total respiratory system differed significantly regardless of whether one or both nostrils were open. With one nostril closed there were no significant effects on any of the measured lung function parameters. We conclude that in healthy awake neonates reducing the cross-sectional area of nasal dimensions by 50% does not affect TFV loops or passive respiratory mechanics.

Humans↗
PubMed1998

Changes in nasal airway dimensions in infancy.

Thirty-nine infants, previously examined as neonates, were re-examined at 1 year of age with continuous wide-band noise acoustic rhinometry using a specific probe optimized for infants, to determine the dimensional growth and maturation of nasal airway geometry in otherwise healthy infants. During the first year of life, the acoustically determined dimensions of the nasal airways increased significantly. The total minimal cross-sectional area increased by 67% (0.21 cm2-->0.35 cm2), the volume of the anterior 4 cm of the nasal airway by 36% (1.80 cm3-->2.44 cm3) and the distance to the minimum cross-sectional area by 19% (0.78 cm-->0.93 cm). The rhinometric values of male infants were significantly larger than those of females. However, after adjusting for the significantly larger anthropometric values of males, the difference disappeared, indicating that it was mainly due to body size and not directly to gender. A highly significant correlation (r=0.44, p < 0.006) was observed between the minimum cross-sectional area and head circumference, which anatomically are the most closely related rhinometric and anthropometric values. Furthermore, when differentiating between infants with or without signs of nasal congestion during the fortnight preceding the rhinometric evaluation, a reduction in the total volume of the anterior 4 cm (17% p <0.02) and minimum cross-sectional area (12%, ns) was observed after adjustment. We conclude that the optimized acoustic rhinometric probe is a useful investigative modality, permitting studies of upper airway physiology of healthy and diseased infants.

Acoustics↗
PubMed1998

Technical abilities and limitations of acoustic rhinometry optimised for infants.

The objective of this model study was to validate in detail the technical capabilities as well as the limitations of a new rhinometric probe optimised for infants in order to improve reliability of measurements and reduce the risk of misleading conclusions. The repeatability was excellent (CV < 0.6%) and the reproducibility was high (CV% < 4%) provided the ambient conditions were fairly stable. The repeatability declined when external noise levels were above 60 dB SPL, and variation in temperature and pressure reduce reproducibility. The accuracy of the minimum cross-sectional area (MCA) as well as the volume corresponding to the nasal cavity in infants (VOL4), was acceptable (% error < 12%) as long as the MCA was larger than 30-40% of the probe dimensions and the cross-sectional area of the cavity posterior to the MCA did not exceed the MCA by a factor of more than 3-4. Variation in the position of the MCA within the anterior 2 cm has minimal influence on the posterior measurements provided the shape and length of the MCA are unaltered. Rods inserted into the tubular model to simulate the slit-like shape of the nasal passage did not reduce the accuracy, which is essential to the clinical value of acoustic rhinometry. Recommendations and guidelines designed to enhance the reliability of acoustic measurements in infants are presented.

Acoustics↗
PubMed1997

Nasal airway dimensions in term neonates measured by continuous wide-band noise acoustic rhinometry.

The nasal airways of 94 healthy term infants (37-42 weeks gestational age) were examined by continuous wide-band noise acoustic rhinometry under standardized conditions on the second or third day postpartum. Validation of the flexible infant probe on tubular plastic models with dimensions similar to the nasal cavity of newborn infants showed a correlation coefficient of 0.98. The mean and standard deviation (SD) of the total minimal cross-sectional area (TMCA), the distance from the nostril to the MCA (DMCA) and the total volumes between the nostril and 45 mm into the nasal cavity (TVOL45) were 0.20 +/- 0.05 cm2, 0.76 +/- 0.29 cm and 2.14 +/- 0.39 cm3 respectively. In general, both anthropometric and rhinometric mean values were higher in males (n = 52) compared to females (n = 42), and the difference was statistically significant for TMCA and head circumference. We conclude that the technical properties, small size and flexible tube of the miniprobe make it uniquely suited for objective assessment of the nasal airways in infants and small children. The RHIN 2000/2100 miniprobe (S.R. Electronics Aps, Lynge, Denmark) is the first infant probe commercially available, making standardization and comparison of results easier.

Acoustics↗
PubMedDate not supplied

Nitric oxide in the nasal airway: a new dimension in otorhinolaryngology.

The discovery that the gas nitric oxide (NO) is an important signaling molecule in the cardiovascular system earned its Nobel prize in 1998. NO has since been found to play important roles in a variety of physiologic and pathophysiologic processes in the body including vasoregulation, hemostasis, neurotransmission, immune defense, and respiration. The surprisingly high concentrations of NO in the nasal airway and paranasal sinuses has important implications for the field of otorhinolaryngology. NO provides a first-line defense against micro-organisms through its antiviral and antimicrobial activity and by its upregulation of ciliary motility. Nasal treatments such as polypectomy, sinus surgery, removal of hypertrophic adenoids and tonsils, and treatment of allergic rhinitis may alter NO output and, therefore, the microbial colonization of the upper airways. Nasal surgery aimed at relieving nasal obstruction may do the same but would also be expected to improve pulmonary function in patients with asthma and upper airway obstruction. NO output rises in a number of conditions associated with chronic airway inflammation, but not all of them. Concentrations are increased in asthma, allergic rhinitis, and viral respiratory infections, but reduced in sinusitis, cystic fibrosis, primary ciliary dysfunction, chronic cough, and after exposure to tobacco and alcohol. Therefore, NO, similar to several other inflammatory mediators, probably subserves different functions as local conditions dictate. At present, it seems that the measurement of NO in the upper airway may prove valuable as a simple, noninvasive diagnostic marker of airway pathologies. The objective of this review is to highlight some aspects of the origin, physiology, and functions of upper airway NO, and to discuss the particular methodological problems that result from the complex anatomy.

Humans↗