The assessment of sniff nasal inspiratory pressure in patients with Duchenne muscular dystrophy in China.

OBJECTIVE: Progressive weakness of respiratory muscles remains one of the leading causes of death among patients with Duchenne muscular dystrophy (DMD). Currently, there are few pulmonary function data among Chinese DMD patients. This study was carried out to evaluate the sniff nasal inspiratory pressure (SNIP) change among a group of Chinese DMD patients, and compare it with the SNIP value of patients with neuromuscular disorders in other countries. METHODS: SNIP data were collected in three research groups that consists of 581 subjects: 125 DMD boys who have taken steroid (Age 5.0-13.3, DMD-steroid group), 145 DMD steroid-naive boys (Age 5.0-13.9, DMD-nonsteroid group), and 311 healthy controls (Age 5.0-14.0, Control group). RESULTS: The SNIP for DMD-nonsteroid group, DMD-steroid group and Control group were: 56.5 (±14.3) cm H2O,66.4 (±15.5) cm H2O and 78.9 (±21.5) respectively. The SNIP in the DMD-nonsteroid group became significantly different from that of the healthy controls since age 7.0-8.9. The significant difference of SNIP between DMD-steroid group and DMD-nonsteroid group at age 7.0-10.9. The peak value of SNIP in the DMD-nonsteroid group appeared at age 8.7, and decreased dramatically thereafter, while in DMD-steroid group and the Control group peaked at 10.2 years and 12.2 years respectively. There was a bit difference between SNIP in this group and that in previous researches which may be due to geographical distribution and ethnic backgrounds. CONCLUSION: This study strengthens the previous findings that SNIP can be used to evaluate respiratory dysfunction during the early stage of young patients with neuromuscular disorders, and demonstrates that steroid is effective in slowing the decrease of SNIP in this group of Chinese DMD boys.

Low cost of pulmonary ventilation in American alligators (Alligator mississippiensis) stimulated with doxapram.

To determine the costs of pulmonary ventilation without imposing severe oxygen limitations or acidosis that normally accompany exposures to hypoxia or hypercapnia, we opted to pharmacologically stimulate ventilation with doxapram (5 and 10 mg kg(-1)) in alligators. Doxapram is used clinically to alleviate ventilatory depression in response to anaesthesia and acts primarily on the peripheral oxygen-sensitive chemoreceptors. Using this approach, we investigated the hypothesis that pulmonary ventilation is relatively modest in comparison to resting metabolic rate in crocodilians and equipped seven juvenile alligators with masks for concurrent determination of ventilation and oxygen uptake. Doxapram elicited a dose-dependent and up to fourfold rise in ventilation, primarily by increasing ventilatory frequency. The accompanying rise in oxygen uptake was very small; ventilation in resting animals constitutes no more than 5% of resting metabolic rate. The conclusion that pulmonary ventilation is energetically cheap is consistent with earlier studies on alligators where ventilation was stimulated by hypoxia or hypercapnia.

Optimization of dual-energy xenon-computed tomography for quantitative assessment of regional pulmonary ventilation.

OBJECTIVE: Dual-energy x-ray computed tomography (DECT) offers visualization of the airways and quantitation of regional pulmonary ventilation using a single breath of inhaled xenon gas. In this study, we sought to optimize scanning protocols for DECT xenon gas ventilation imaging of the airways and lung parenchyma and to characterize the quantitative nature of the developed protocols through a series of test-object and animal studies. MATERIALS AND METHODS: The Institutional Animal Care and Use Committee approved all animal studies reported here. A range of xenon/oxygen gas mixtures (0%, 20%, 25%, 33%, 50%, 66%, 100%; balance oxygen) were scanned in syringes and balloon test-objects to optimize the delivered gas mixture for assessment of regional ventilation while allowing for the development of improved 3-material decomposition calibration parameters. In addition, to alleviate gravitational effects on xenon gas distribution, we replaced a portion of the oxygen in the xenon/oxygen gas mixture with helium and compared gas distributions in a rapid-prototyped human central-airway test-object. Additional syringe tests were performed to determine if the introduction of helium had any effect on xenon quantitation. Xenon gas mixtures were delivered to anesthetized swine to assess airway and lung parenchymal opacification while evaluating various DECT scan acquisition settings. RESULTS: Attenuation curves for xenon were obtained from the syringe test-objects and were used to develop improved 3-material decomposition parameters (Hounsfield unit enhancement per percentage xenon: within the chest phantom, 2.25 at 80 kVp, 1.7 at 100 kVp, and 0.76 at 140 kVp with tin filtration; in open air, 2.5 at 80 kVp, 1.95 at 100 kVp, and 0.81 at 140 kVp with tin filtration). The addition of helium improved the distribution of xenon gas to the gravitationally nondependent portion of the airway tree test-object, while not affecting the quantitation of xenon in the 3-material decomposition DECT. The mixture 40% Xe/40% He/20% O2 provided good signal-to-noise ratio (SNR), greater than the Rose criterion (SNR > 5), while avoiding gravitational effects of similar concentrations of xenon in a 60% O2 mixture. Compared with 100/140 Sn kVp, 80/140 Sn kVp (Sn = tin filtered) provided improved SNR in a swine with an equivalent thoracic transverse density to a human subject with a body mass index of 33 kg/m. Airways were brighter in the 80/140 Sn kVp scan (80/140 Sn, 31.6%; 100/140 Sn, 25.1%) with considerably lower noise (80/140 Sn, coefficient of variation of 0.140; 100/140 Sn, coefficient of variation of 0.216). CONCLUSION: To provide a truly quantitative measure of regional lung function with xenon-DECT, the basic protocols and parameter calibrations need to be better understood and quantified. It is critically important to understand the fundamentals of new techniques to allow for proper implementation and interpretation of their results before widespread usage. With the use of an in-house derived xenon calibration curve for 3-material decomposition rather than the scanner supplied calibration and a xenon/helium/oxygen mixture, we demonstrate highly accurate quantitation of xenon gas volumes and avoid gravitational effects on gas distribution. This study provides a foundation for other researchers to use and test these methods with the goal of clinical translation.

Minimum effective volume of local anesthetic for shoulder analgesia by ultrasound-guided block at root C7 with assessment of pulmonary function.

BACKGROUND AND OBJECTIVES: This study was performed to determine the minimum effective volume of ropivacaine 0.75% required to produce effective shoulder analgesia for an ultrasound (US)-guided block at the C7 root level with assessment of pulmonary function. METHODS: Using the Dixon and Massey up-and-down method study design, 20 patients scheduled for elective open shoulder surgery under combined general anesthesia and continuous interscalene brachial plexus block were included. Initial volume of ropivacaine 0.75% was 6 mL; block success or failure determined a 1-mL decrease or increase for the subsequent patient, respectively. General anesthesia was standardized. A continuous infusion of ropivacaine 0.2% was started at a rate of 6 mL/hr at 2 hrs after completion of surgery. Ventilatory function was assessed using spirometry, and movement of the hemidiaphragm was assessed by US. RESULTS: The minimum effective volume of local anesthetic in 50% and 95% of the patients was 2.9 mL (95% confidence interval, 2.4-3.5 mL) and 3.6 mL (95% confidence interval, 3.3-6.2 mL), respectively. Ventilatory function and hemidiaphragmatic movement was not reduced up to and including 2 hrs after completion of surgery, but 22 hrs after start of the continuous infusion of ropivacaine 0.2%, ventilatory function and hemidiaphragmatic movement were significantly reduced (P < 0.001). CONCLUSIONS: The minimum effective volume of local anesthetic for shoulder analgesia for a US-guided block at the C7 root level in 50% and 95% of the patients was 2.9 and 3.6 mL, respectively. Pulmonary function was unchanged until 2 hrs after completion surgery, but reduced 22 hrs after start of a continuous infusion of ropivacaine 0.2%.

No evidence for the development of acute tolerance to analgesic, respiratory depressant and sedative opioid effects in humans.

It is widely accepted that chronic opioid therapy is associated with the development of pharmacological tolerance. More controversial is the question as to whether acute opioid administration can result in "acute tolerance." The aim of this double-blind, placebo-controlled study in thirty-six healthy human volunteers was to examine whether a 3-h intravenous infusion delivering two different but clinically relevant doses of the mu-opioid receptor agonist remifentanil would result in tolerance to analgesic, respiratory depressant and/or sedative opioid effects. The blood remifentanil concentration versus opioid effect relationship was determined before and after the 3-h infusion. Tolerance was inferred if the potency of remifentanil was significantly lower after the 3-h infusion. Opioid analgesia was assessed with the aid of the cold pressor test and models of electrical and heat pain. Respiratory depression was assessed by measuring arterial pCO2 and minute ventilation. Subjective sedation scores were assessed on a visual analogue scale. Mixed effects modeling was used to relate the steady-state blood remifentanil concentration to each pharmacodynamic assessment. Neither dose of remifentanil produced detectable tolerance to any of the measured opioid effects following a 3-h infusion. The study was adequately powered to detect a decrease in potency of 5-24% for analgesia, 20-48% for respiratory depression, and 32% for sedative effects. These results suggest that short-term administration of clinically useful doses of remifentanil is not associated with the development of significant tolerance to analgesic, respiratory depressant, or sedative opioid effects.

Assessment of the antiobstructive effect of fexofenadine on nasal allergy challenge in patients with seasonal allergic rhinitis.

The oral administration of fexofenadine 120 mg daily is a common treatment of seasonal allergic rhinitis (SAR). It reduces the H1 receptor-mediated symptoms, such as sneezing, pruritus, and nasal secretion as well as non-nasal symptoms such as conjunctivitis. The objective was to assess the effect of fexofenadine on nasal symptoms (such as nasal obstruction) in seasonal allergic rhinitis. A placebo-controlled, double-blind, randomized, cross-over study was performed which yielded evidence that two-week therapy with fexofenadine 120 mg daily in patients with SAR also relieves nasal obstruction and congestion. The parameters of nasal obstruction were evaluated by means of rhinoscopy, a subjective symptom score, and active anterior rhinomanometry. The subjective evaluation of nasal obstruction/congestion as recorded by the patient every 15 minutes for 4.5 hours after nasal allergen provocation showed a significant difference of the AUC (p = 0.025) between fexofenadine and placebo with a 12.8% lower obstruction after fexofenadine. The swelling of the nasal mucosa, which was assessed by rhinoscopy for 4.5 hours after nasal allergen provocation, was 21% lower after treatment with fexofenadine (p = 0.041). In this double-blind, placebo-controlled trial, subjective patient ratings as well as objective investigator assessments demonstrate the anti-obstructive effect of fexofenadine in nasal allergen challenge.

Effect of atorvastatin on energy expenditure and skeletal muscle oxidative metabolism at rest and during exercise.

Statins are associated with adverse effects in skeletal muscle. This study tested the hypothesis that atorvastatin would increase the respiratory exchange ratio (RER) at rest and during exercise. Twenty-eight healthy subjects (mean age 52 years) were enrolled in a double-blind, placebo-controlled, randomized study of the effects of atorvastatin (40 mg/day) on whole body energetics over 8 weeks. Ventilatory gas exchange measurements, at rest and during bicycle ergometry, were used to assess muscle oxidative metabolism. Thirteen subjects from each treatment arm completed the study. Eight weeks of atorvastatin lowered plasma low-density lipoprotein cholesterol concentration but had no effect on resting or submaximal energy expenditure, RER, or calculated fatty acid oxidation rates. Atorvastatin did not affect maximal exercise oxygen consumption or the anaerobic threshold. Eight weeks of atorvastatin therapy was not associated with alterations in substrate oxidation, or muscle oxidative function at rest, or during exercise in healthy adults.

Non-invasive assessment of airway responsiveness in healthy and allergen-sensitised cats by use of barometric whole body plethysmography.

This study aimed at determining whether airway responsiveness (AR) tests performed by use of barometric whole body plethysmography (BWBP) were repeatable in cats and to what extent AR was affected by the nebulization protocol used, the age of the animals, the inflammatory status of the airways and prior bronchodilator treatment. Repeatability of AR was tested on two occasions in 30 healthy cats. The concentration of carbachol inducing a 300% increase of the enhanced pause (Penh)--an estimator of airflow limitation--was calculated (C-Penh300) and did not differ significantly between the two tests (0.035+/-0.017% compared to 0.034+/-0.016%) and was significantly and positively correlated. The comparison between rapidly and slowly increasing carbachol concentrations was performed in ten healthy cats and showed a significantly lower C-Penh300 (%) when slowly increasing concentrations were used (0.037+/-0.013% compared to 0.039+/-0.015%, P<0.05). A significant age-related increase of C-Penh300 was evidenced by performing AR tests in 15 healthy cats at 12, 18, 24 and 30 months (12 months: 0.026+/-0.008%, 18 months: 0.031+/-0.009%, 24 months: 0.038+/-0.01%, 30 months: 0.043+/-0.014%, P<0.05). C-Penh300 significantly decreased in 12 Ascaris suum-sensitised cats after allergen exposure (0.026+/-0.016% compared to 0.033+/-0.016%, P<0.05) and was negatively correlated with the granulocyte percentage of bronchoalveolar lavage fluid (r=-0.36, P<0.01). Compared with a placebo inhalation, pre-treatment with inhaled salbutamol significantly increased C-Penh300 in four healthy cats (0.093+/-0.021% compared to 0.036+/-0.004%, P<0.05). This study provides evidence that AR determination by use of BWBP is promising as non-invasive indicator of lower airway inflammation or for monitoring response to bronchodilator treatment.

Adjustable maintenance dosing with budesonide/formoterol compared with fixed-dose salmeterol/fluticasone in moderate to severe asthma.

BACKGROUND: Current asthma guidelines recommend that patients are educated to adjust their medication according to their asthma severity using physician-guided self-management plans. However, many patients take a fixed dose of their controller medication and adjust their reliever medication according to asthma symptoms. OBJECTIVES: This study examined whether asthma control improved if patients adjusted the maintenance dose of budesonide/formoterol (Symbicort Turbuhaler* 160/4.5 microg) according to asthma severity compared with traditional fixed dosing (FD) regimens. METHODS: Symptomatic patients with asthma (n = 658, mean symptom score 1.5, mean inhaled corticosteroids 735 microg/day, mean forced expiratory volume in 1 second [FEV(1)] 84% predicted) were randomised after 2 weeks' run-in to either: budesonide/formoterol adjustable maintenance dosing (AMD), budesonide/formoterol FD or salmeterol/fluticasone (Seretide Diskus dagger 50/250 microg) FD. In a 4-week double-blind period, both budesonide/formoterol AMD and FD groups received two inhalations twice daily (bid) and salmeterol/fluticasone FD patients received one inhalation bid. In the following 6-month open extension, both FD groups continued with the same treatment. Patients in the AMD group with well-controlled asthma stepped down to one inhalation bid; others continued with two inhalations bid. All AMD patients could increase to four inhalations bid for 7-14 days if symptoms worsened. All patients used terbutaline or salbutamol for symptom relief throughout. The primary variable was the odds of achieving a well-controlled asthma week (WCAW). RESULTS: The odds ratio for achieving a WCAW did not differ between the FD regimens; however, during the open period, budesonide/formoterol AMD increased the odds of achieving a WCAW vs. budesonide/formoterol FD (odds ratio 1.335; 95% CI: 1.001, 1.783; p = 0.049) despite a 15% reduction in average study drug use. Budesonide/formoterol AMD patients had a lower exacerbation rate over the study: 40% lower vs. salmeterol/fluticasone FD (p = 0.018); 32% lower vs. budesonide/formoterol FD (NS). During the double-blind period, there were no clinically relevant differences between the budesonide/formoterol FD and salmeterol/fluticasone FD groups. Budesonide/formoterol AMD patients used less reliever medication in the open extension: 0.58 vs. 0.92 occasions/day for budesonide/formoterol FD (p = 0.001) and 0.80 occasions/day for salmeterol/fluticasone FD (p = 0.011). CONCLUSIONS: Adjustable maintenance dosing with budesonide/formoterol provides more effective asthma control by reducing exacerbations and reliever medication usage compared with fixed-dose salmeterol/fluticasone.

Maximal ventilation assessment in healthy calves.

In order to define a reliable method for estimating maximal ventilation in cattle, 12 healthy calves underwent a rebreathing trial and injections of increasing doses of lobeline, a respiratory analeptic. The effects of these tests on the main ventilatory parameters (tidal volume, VT; respiratory frequency, fRand minute volume,.VE) recorded during the 15 s of maximal response were studied and compared. The sharp rise in.VE(4.8 times higher than the resting value) observed during the rebreathing trial was mainly due to an increase in VT. This rise in ventilation was the highest ever reported in calves. Lobeline dose-dependently enhanced ventilation up to a threshold dose of 0.25 mg/kg, which always produced a maximal response. This maximal response (3.7 times higher than the resting value), reflecting both an increase in fR and VT, was reproducible at an interval of 12 h and was highly correlated with that observed during the rebreathing trial (R = 0.98, P< 0.001). These results suggest that: (1) rebreathing trial is a reliable method to induce and measure maximal ventilation in calves; and (2) lobeline administration (0.25 mg/kg) is a reliable means of accurately estimating this variable. Lobeline administration, unlike the rebreathing trial, is safe and easy to standardize, and the test therefore seems to be the preferred way of studying maximal ventilation in calves.

Nasal resistance--a reliable assessment of nasal patency?

This study was undertaken to determine the distribution of nasal resistance in a healthy white population. One hundred subjects without nasal complaints were selected for the investigation. The test subjects were divided into two groups on the basis of anterior rhinoscopy. Group 1 included 60 subjects with rhinoscopically normal noses. Group 2 included 40 subjects with rhinoscopically abnormal noses. The pressure-flow data were recorded via active anterior mask rhinomanometry. The analogue pressure and flow signals were sampled and digitized by a computer system according to the time averaging method. Nasal resistance was calculated according to the recommendations of the International Committee on Standardization of Rhinomanometry. The normality of unilateral nasal resistance data distributions was assessed by the Kolmogorov-Smirnov Goodness of Fit Test at inspiratory and expiratory corresponding pressures of 50 Pa, 75 Pa, 100 Pa, and 150 Pa. The distributions of the calculated total resistance data were estimated at inspiratory and expiratory reference pressures of 75 Pa and 100 Pa. The data distributions of the two groups were compared using the Mann-Whitney U-test. Distributions for unilateral resistance were frequently found to deviate from normality. The distributions of total nasal resistance data never showed significant deviation from normality. More non-normal distributions were observed in Group 2 than in Group 1. Significant differences were determined between the two sub-groups for the non-decongested data. The entire group of subjects was homogeneous for the decongested data. The subjective assessment of nasal patency appeared not to be a sufficient criterion for the selection of subjects for normative studies in rhinomanometry. The presence of anatomical abnormalities and the influence of the nasal cycle could be responsible for the skewness of nasal resistance data in the normative studies in rhinomanometry.

Correlations between subjective sensation of nasal patency and rhinomanometry in both unilateral and total nasal assessment.

The correlation between rhinomanometry and subjective sensation of nasal obstruction was studied. Patients assessed their nasal airway patency using a visual analogue scale (VAS). The VAS results and rhinomanometry correlated better when unilateral nasal obstruction was evaluated compared to total nasal evaluation. When rhinomanometric data were divided into four clinically relevant grades of obstruction (very patent, normal, obstructed and very obstructed) and the quartiles of the VAS results were compared to these, the agreement was good or fairly good in 75-85% of cases. A similar result was also encountered when, in an experimental study, 30 individuals were asked to breathe through four artificial nose models with a varying inner diameter of 9-3 mm. Again, most subjects assessed these models logically, but in 11% of the cases the subject assessed the narrowest tube as patent or the widest tube as very obstructed. Our results prove the necessity of having some sort of objective method to evaluate nasal patency; if we rely only on the patient's sensation, we may get a misleading picture of his nasal function.

Assessment of reversibility of airflow obstruction.

The application of the forced oscillation technique to assess reversibility of airflow obstruction was compared with that of indices of forced expiration and plethysmographic airway resistance (Raw). In 125 patients with airflow obstruction, we measured total respiratory resistance (Rrs) and reactance (Xrs), Raw and specific airway conductance (sGaw), maximal flow-volume curves and forced expiratory volume in 1 s (FEV1), before and 30 min after 2 x 20 micrograms salbutamol by MDI. Salbutamol induced significant change in mean value of all measured indices. The changes in impedance data consisted of decrease in mean value and of negative frequency dependence of Rrs, an increase in Xrs with slight decrease of its positive frequency dependence. Multivariate analysis of differences between pre- and postbronchodilator values showed that the single indices with the greatest sensitivity to detect the effect of salbutamol were, in decreasing order, (1) in relative change (% baseline value): Raw, Rrs at 6 Hz (Rrs6), forced vital capacity (FVC), FEV1, and (2) in absolute change: FVC, sGaw or Raw, Rrs6, FEV1, maximal expiratory flow (MEF50). The effect of salbutamol was described best in (1) by a combination of Raw and FVC and in (2) by sGaw and FVC. For individual detection of bronchodilator effect, threshold values were calculated from mean reproducibility of the three baseline values of the various indices, attempting to estimate whether response to a bronchodilator is statistically significant. The greatest number of significant responses were observed for Raw, sGaw, FEV1, and FVC in that succession, Rrs6 being markedly less sensitive. This discrepancy is due to the lack of Rrs6 response to bronchodilators in patients with severe airway obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Steroid trials in the assessment of reversibility of air flow limitation: a survey of current clinical practice of chest physicians.

To evaluate how steroid trials are currently used in the assessment of reversibility of air flow limitation, a postal questionnaire was sent to 355 consultant members of the British Thoracic Society working in England and Wales; 253 questionnaires were returned (71% response rate). Two respondents did not undertake steroid trials; of the remaining 251, 75% prescribed 30-40 mg oral prednisolone, with the commonest treatment period being 2 weeks. A high dose steroid inhaler was sometimes used as an alternative by 31% of respondents. Although 71% of respondents made lung function measurements on several occasions before starting steroids and 76% made measurements during treatment, 78% assessed patients on only one occasion at the end of the trials to ascertain its outcome. Weight, blood pressure and glycosuria were measured less frequently after the steroid treatment compared to the pre-trial period. Blood glucose and serum electrolytes were infrequently measured both before and after treatment. Wide variations exist in steroid trial regimens and current practice may neither provide definitive evidence of treatment benefit nor an adequate safeguard for patients against potential side-effects.

Comparison of the constant flow and occlusion methods for assessment of bronchoconstriction in guinea-pigs.

Assessments of total respiratory compliance (C) and conductance (G) with the constant inspiratory flow and the occlusion methods were compared in the basal state and during histamine or serotonin induced bronchoconstriction in 22 normal, anaesthetized, paralysed, mechanically ventilated guinea-pigs. In the basal state, no significant difference was found between the C and G values measured by both methods. During drug-induced bronchoconstriction, small but significant differences were observed between the respiratory parameters measured by the two methods, and expressed as the percentage ratio (R) to the corresponding basal values (respectively RCCF and RCOC, and RGCF and RGOC). This discrepancy, which was independent of the drug and of the dose, was probably attributable to a modification of the visco elastic properties of the lung due to either the mechanical ventilation or the infused drug. Nevertheless, this study demonstrates that both methods can be considered as equivalent for bronchoconstriction assessment because very strong correlations were found between RCCF and RCOC (r = 0.96, p less than 0.001) and between RGCF and RGOC (r = 0.97, p less than 0.001), and because the slopes of the linear relationships were not significantly different from unity in both cases.

Respiratory mechanics for assessment of histamine bronchopulmonary reactivity in guinea pigs.

In the course of bronchial challenge, bronchopulmonary response assessment requires pleural pressure measurement. This measurement, mostly obtained in guinea pigs by a pleural catheter, is difficult to perform in anaesthetized paralysed ventilated animals needing periodical large inflations. The aim of this study was to demonstrate that the pulmonary response to intravenous histamine can be correctly appreciated from the respiratory response. In twelve anaesthetized paralysed mechanically ventilated guinea pigs, pulmonary and respiratory compliances (CL and Crs), were measured together with pulmonary and respiratory conductances (GL and Grs), using the method proposed by Rossi et al. (J. Appl. Physiol. 58: 1849-1858, 1985). Pulmonary and total respiratory mechanics were compared in the basal state, and at the end of a 5 min histamine infusion (100 ng.kg-1.sec-1). Pulmonary and respiratory compliances under histamine (HCL and HCrs), as well as pulmonary and respiratory conductances under histamine (HGL and HGrs), were expressed as a percentage of the corresponding basal values. Highly significant correlations were found between HCL and HCrs on the one hand (r = 0.98, P less than 0.001), and HGL and HGrs on the other (r = 0.97, P less than 0.001). We conclude that, in guinea pigs, the response of the total respiratory system to histamine infusion provides a simple and accurate assessment of the pulmonary response.

Assessment of nasal airway patency: a comparison of four methods.

Two established methods (active posterior and passive anterior rhinomanometry) and 2 new methods (peak nasal inspiratory flow rate and apparent nasal volume) were used in 12 volunteers to assess the patency of the nasal airways under each of 4 conditions (baseline, post-exercise, nasal histamine and nasal cocaine). All methods showed the congestant effect of histamine but the peak nasal inspiratory flow and apparent nasal volume techniques were more sensitive to the 'decongesting' manoeuvres, (exercise and cocaine). Useful objective quantitative data on the patency of the nasal airways and its changes in response to stimuli can be obtained by simple, cheap and readily available techniques. Subjective sensation is a poor guide to the state of patency of the nasal airways.

Assessment of the correlation of rhinometry with the symptoms and signs of allergic rhinitis in children.

The measurement of nasal patency by anterior rhinometry is a potentially useful tool in evaluating patients with various forms of rhinitis. This study measured both nasal air flow by anterior rhinometry and symptom/sign scores in 49 children with perennial allergic rhinitis. We found that anterior rhinometry in children is (1) a simple, rapid procedure, (2) well accepted by the pediatric patient, and (3) a valid technique for objectively assessing and quantifying the somewhat subjective parameters that physicians traditionally follow for allergic rhinitis.